WO2008063134A1

WO2008063134A1 - Method of producing a pattern of discriminative wettability

Info

Publication number: WO2008063134A1
Application number: PCT/SG2006/000362
Authority: WO
Inventors: Nam Yong Kim; Y. Jackie Ying; Hua Zhang; Yong Yeow Lee; Kwong Joo Leck
Original assignee: Agency For Science, Technology And Research
Priority date: 2006-11-24
Filing date: 2006-11-24
Publication date: 2008-05-29

Abstract

The present invention relates to a method of producing a pattern of discriminative wettability on the surface of a substrate (2). The method includes patterning the surface of the substrate such that a plurality of accessible surface areas is defined. The method also includes depositing only on the plurality of accessible surface areas photocatalytic matter (4), and depositing on the entire surface oxidisable matter (5). The oxidisable matter (5) is of a wettability that differs from the wettability of the photocatalytic matter (4), and at least essentially inert to an exposure of electromagnetic radiation that is sufficient to cause the photocatalytic matter (4) to catalyse the oxidation of the oxidisable matter (5). The method further includes exposing the entire surface to electromagnetic radiation, such that the photocatalytic matter (4) catalyses the oxidation of such oxidisable matter (5) that is in contact therewith. Thereby the oxidisable matter (5) is removed from the plurality of surface areas and the photocatalytic matter (4) on these surface areas exposed, while the oxidisable matter (5) is at least essentially preserved on the remaining surface of the substrate.

Description

METHOD OF PRODUCING A PATTERN OF DISCRIMINATIVE WETTABILITY

FIELD OF THE INVENTION

[001] The present invention relates to a method of producing a pattern of discriminative wettability on the surface of a substrate.

BACKGROUND OF THE INVENTION

[002] Microarrays of biomaterials, consisting of either DNA, proteins or cells, have found widespread applications in disease diagnosis, pathogen detection, biomarker discovery and analysis of biomarker interaction. Often the scope and performance of bio-microarrays are determined by the quality of coatings employed for surface patterning. Patterned surfaces have been fabricated by many methods including micro-contact printing micro-fluidic lithography and conventional photolithography. [003] Using such methods, hydrophilic-hydrophobic micropatterns have also been obtained. Kanta et al. (Langmuir [2005] 21, 5790-5794) obtained a silica pattern on a titania surface by photolithography using a photoresist on the titania surface, followed by silica coating and subsequent heat exposure. However, the accurate removal of photoresist both by means of a photomask and a final thermal lift-off pose practical challenges. Japanese patent application 2005-003803 discloses a method of manufacturing hydrophobicity difference patterns by irradiating fluoroalkylsilane coated glass in the presence of an additional titanium oxide coated glass plate. In the method of this publication, the two surfaces are separated by a distance of less than 200 μm. A different approach of obtaining a micropattern generates a surface with silicon-hydrogen bonds (English abstract of international patent application WO 2006/046699). In some areas the silicon-hydrogen surface is then reacted with a water- repellent compound in a hydrosilylation reaction, while in other areas it is reacted to a hydrophilic area.

[004] Methods such as micro-contact printing and micro-fluidic lithography have limited practical applications due to several disadvantages. They lack for example reliability and consistency, particularly in industrial scale-up. Furthermore, the methods of micro- contact printing and micro-fluidic lithography are often incompatible with popular coating conditions, such as long exposure to organic solvents or high-temperature vapour-phase deposition. Similarly, conventional photolithographic methods for surface patterning limit the range of coating reagents and methods available due to the presence of photoresist films. In addition, the photoresist films could leave residual materials on the surface, which could interfere with subsequent surface coating. Most important of all, these patterned surfaces can be used only once in spite of the significant fabrication cost and time involved. [005] These methods are generally also cost intensive, so that it would be desirable to provide a micropattern, at least parts of which can be reused without the requirement to produce a new substrate with an entire new pattern.

[006] Furthermore the wettability properties of titanium oxide change upon storage, in particular after an exposure to irradiation such as UV light or storage under room light, hi an approach to avoid this disadvantage, Gu et al. (Angew. Chem. Int. Ed (2002) 41, 12, 2068- 2070) suggested the fabrication of a fluoroalkylsilane film on a titanium oxide surface followed by two repeated steps of replacing the fluoroalkylsilane film in selected areas by (1) polystyrene or silica spheres that are subsequently fluoridated, and (2) silica spheres.

[007] Accordingly, it is an object of the present invention to provide a method of pattern of discriminative wettability on a surface that avoids these disadvantages and that can be reused without the requirement of fabricating an entire new substrate.

SUMMARY OF THE INVENTION

[008] hi one aspect the present invention provides a method of producing a pattern of discriminative wettability on the surface of a substrate. The method includes providing a substrate. The method further includes patterning the surface of the substrate. By a respective patterning a plurality of accessible surface areas is defined. The method also includes depositing only on said plurality of accessible surface areas photocatalytic matter.

The method further includes depositing on the entire surface, including the plurality of accessible surface areas, oxidisable matter. The oxidisable matter is of a wettability that differs from the wettability of the photocatalytic matter. The oxidisable matter is furthermore at least essentially inert to an exposure of electromagnetic radiation that is sufficient to cause the photocatalytic matter to catalyse the oxidation of the oxidisable matter. The method also includes exposing the entire surface to electromagnetic radiation. As a result the photocatalytic matter catalyses the oxididation of such oxidisable matter that is in contact therewith. Thereby the oxidisable matter is removed from the plurality of surface areas. The photocatalytic matter on these surface areas is thereby exposed. Furthermore the oxidisable matter on the remaining surface of the substrate is at least essentially preserved. As a result a pattern of discriminative wettability is formed.

[009] By this method of the invention the remaining area of the surface is thus covered with oxidisable matter. The plurality of surface areas is covered with photocatalytic matter. According to some embodiments of the method of the invention the photocatalytic matter is removed by etching, thereby uncovering the plurality of surface areas and exposing the substrate surface in the respective surface areas. The surface can then be reused for e.g. depositing photocatalytic matter thereon.

[010] According to a particular embodiment, the method includes depositing on the entire surface, including the plurality of accessible surface areas, oxidisable matter that is hydrophobic. The hydrophobic oxidisable matter is of a lower wettability for water when compared to the photocatalytic matter. As indicated above, the hydrophobic oxidisable matter is at least essentially inert to an exposure of electromagnetic radiation that is sufficient to cause the photocatalytic matter to catalyse the oxidation of the hydrophobic oxidisable matter. As a result of exposing the entire surface to electromagnetic radiation the photocatalytic matter catalyses the oxididation of such hydrophobic oxidisable matter that is in contact therewith. Thereby the hydrophobic oxidisable matter is removed from the plurality of surface areas. The photocatalytic matter on these surface areas is thereby exposed. Furthermore the hydrophobic oxidisable matter on the remaining surface of the substrate is at least essentially preserved. As a result a pattern of discriminative hydrophobicity, and thereby of discriminative wettability, is formed.

[011] According to some embodiments, this method of the invention further includes depositing a substance, which may include a molecule with a linking moiety, on the photocatalytic matter that covers the plurality of surface areas. Depositing such matter may be used for immobilising a molecule on the plurality of surface areas, for example via a respective linking moiety.

[012] In another aspect the present invention provides a further method of producing a pattern of discriminative wettability on the surface of a substrate. This method also includes providing a substrate. The method further includes depositing on the entire surface of the substrate photocatalytic matter. Further, the method includes vapour coating the entire surface with oxidisable matter. The oxidisable matter is of a wettability that differs from the wettability of the photocatalytic matter. The oxidisable matter is furthermore at least essentially inert to an exposure of electromagnetic radiation that is sufficient to cause the photocatalytic matter to catalyse the oxidation of the oxidisable matter. The method further includes patterning the surface of the substrate. By a respective patterning a plurality of accessible surface areas is defined. The method also includes exposing only said plurality of accessible surface areas to electromagnetic radiation. As a result the photocatalytic matter catalyses the oxidation of such oxidisable matter that is in contact therewith. Thereby the oxidisable matter is removed from the plurality of surface areas. The photocatalytic matter on these surface areas is thereby exposed. Furthermore the oxidisable matter on the remaining surface of the substrate is at least essentially preserved. As a result a pattern of discriminative wettability is formed.

[013] In further aspect the present invention provides a further method of producing a pattern of discriminative wettability on the surface of a substrate. The method includes providing a substrate. The method further includes depositing on the entire surface of the substrate photocatalytic matter. Further, the method includes depositing on the entire surface oxidisable matter. The oxidisable matter is of a wettability that differs from the wettability of the photocatalytic matter. The oxidisable matter is furthermore at least essentially inert to an exposure of electromagnetic radiation that is sufficient to cause the photocatalytic matter to catalyse the oxidation of the oxidisable matter. The method further includes patterning the surface of the substrate. By a respective patterning a plurality of accessible surface areas is defined. The method also includes exposing only said plurality of accessible surface areas to electromagnetic radiation. As a result the photocatalytic matter catalyses the oxididation of such oxidisable matter that is in contact therewith. Thereby the oxidisable matter is removed from the plurality of surface areas. The photocatalytic matter on these surface areas is thereby exposed. Furthermore the oxidisable matter on the remaining surface of the substrate is at least essentially preserved. The method further includes at least essentially removing the photocatalytic matter by means of etching. Thereby the method includes at least essentially uncovering the plurality of surface areas of the substrate. Thereby the method also includes at least essentially preserving the oxidisable matter on the remaining surface of the substrate. As a result a pattern of discriminative wettability is formed.

[014] In yet a further aspect the invention relates to a pattern of discriminative wettability on the surface of a substrate, obtained by a method of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[015] The invention will be better understood with reference to the detailed description when considered in conjunction with the non-limiting examples and the accompanying drawings, in which:

[016] Figure 1 depicts a surface of a substrate (2) with a pattern of discriminative wettability, as well as schematic indications referring to methods of producing a respective pattern according to the present invention. The pattern includes surface areas of photocatalytic matter (4) and oxidisable matter (5).

[017] Figure 2A depicts a schematic representation of a method according to the present invention. The box depicts the basic steps of the method. I: On a surface (1) of a substrate (2) a plurality of accessible surface areas (3) is patterned, on which photocatalytic matter is to be deposited. II: Photocatalytic matter (4) is deposited on the respective surface areas. Ill: Since the photocatalytic matter (4) only covers the plurality of accessible surface areas, the remaining surface area of the substrate remains unaltered. IV: Hydrophobic oxidisable matter (5) is deposited on the surface (1). V: Both the previously unaltered surface of the substrate (2) and the photocatalytic matter (4) are covered with the hydrophobic oxidisable matter (5), which therefore covers the entire surface (1). VI: The entire surface covered with the hydrophobic oxidisable matter (5) is exposed to electromagnetic radiation. VII: As a result the photocatalytic matter (4) oxidises the hydrophobic oxidisable matter (5) that is in contact therewith, causing the removal of such hydrophobic oxidisable matter that covers the photocatalytic matter (4). VIII: Optionally the uncovered titanium oxide may be removed by etching. IX: Thereby the substrate surface (1) is uncovered in the plurality of surface areas and only the remaining surface area of the substrate remains covered by the hydrophobic oxidisable matter (5). X: As a further option, a substance that includes a molecule with a linking moiety (6) can be deposited on the plurality of surface areas. XI: Thereby the photocatalytic matter (4) is covered with such substance (6). XII: A target molecule (7) with an affinity for the linking moiety (6) can be deposited on the plurality of surface areas. XIII: As a result, the target molecule (7) is immobilised via the molecule with a linking moiety (6). The substance including a molecule with a linking moiety (6), as well as any target molecule (7) immobilised thereon, may be removed together with the titanium oxide by etching (VIII). Alternatively, the substance including a molecule with a linking moiety (6), including any target molecule (7) immobilised thereon, may be removed by exposing the entire surfaced to electromagnetic radiation (XIV). The uncovered titanium oxide may then be removed by etching (VIII). The hydrophobic oxidisable matter may also be removed, for example by means of an oxygen plasma (XV). [018] Fig. 2B depicts a schematic representation of exemplary methods of depositing photocatalytic matter (4) on the plurality of surface areas (cf. Fig. 2A). According to one method, there is placed a photomask (4) above the surface (1) of a substrate (2), to cover the remaining surface (I) of the substrate. II: Using a sputter photocatalytic matter (4) is deposited on the surface. Ill: Due to the use of the photomask the photocatalytic matter (4) only covers the plurality of surface areas (cf. Fig. 2A).

[019] Fig. 2C depicts a schematic representation of a further method according to the present invention. On a surface (1) there is deposited photocatalytic matter (2) using a sputter (I). Hydrophobic oxidisable matter (5) is deposited on the substrate (1) (II). A photomask (7) is placed above the hydrophobic surface (III), which is exposed to electromagnetic radiation (IV) via the photomask, causing the photocatalytic matter to catalyse the removal of hydrophobic oxidisable matter that covers the photocatalytic matter. Optionally the uncovered photocatalytic matter may be removed by etching (V), thereby exposing the substrate surface. [020] Figure 3 depicts examples of haloalkylsilanes that may be used as hydrophobic oxidisable matter in a method according to the invention.

[021] Figure 4 depicts advancing or receding contact angles of water on mixed anatase- amorphous titanium oxide surfaces subjected to different periods of UV irradiation. The uncertainty in contact angle measurement was ± 2°. [022] Figure 5A depicts a photograph of a glass chip with a surface that comprises a pattern of discriminative hydrophobicity. Stained aqueous solution (dark) is adsorbed only on the hydrophilic areas of the surface. Figure 5B shows a typical fluorescence image of a respectively patterned glass chip, where the wash solution (0.05 % Tween 20 in 50 mM Tris buffer containing 10 μM Fluorescein) is adsorbed only onto the hydrophilic glass areas. [023] Figure 6 depicts the adsorption and growth of HepG2 cells on hydrophilic areas of a surface produced according to a method of the invention, comprising pattern of discriminative hydrophobicity. Photos were taken on (A, D) day 1, (B, E) day 6, and (C, F) day 8, after the chip was seeded with 0.8 μl of HepG2 cells (20 cells/μl).

DETAILED DESCRIPTION OF THE INVENTION

[024] The present invention provides a method of producing a pattern of discriminative wettability on the surface of a substrate. Any surface may be used for the method of the invention, on which a selected photocatalytic matter and selected oxidisable matter can be deposited (see below). The surface may for instance be of any shape and material, as long as it is capable of accommodating a photocatalytic matter and oxidisable matter, and as long as it is compatible with the selected conditions for depositing and irradiating. Any desired substrate may be used. Generally, the substrate may for example be made of or comprise any material, as long as its surface is suitable for the method of the invention (see above). Typically the substrate is of a solid material. As an example, a suitable surface, including a surface of such a substrate, may comprise a metal, a metalloid, ceramics, a metal oxide, a metalloid oxide or oxide ceramics. Examples of suitable metalloids include, but are not limited to silicon, boron, germanium, antimony and composites thereof. Examples of suitable metals include, but are not limited to iron (e.g. steel), aluminium, gold, silver, chromium, tin, copper, titanium, zinc, aluminium, lead and composites thereof. A respective oxide of any of these metalloids and metals may be used as a metalloid oxide or metal oxide respectively. As an illustrative example, the surface may be of quartz or glass. As a further illustrative example, a silicon oxide or germanium oxide surface may be obtained by etching a silicon substrate or germanium substrate, respectively, with piranha solution, i.e. a mixture of sulphuric acid and hydrogen peroxide solution at a molar ratio of 7:3. Examples of ceramics include, but are not limited to, silicate ceramics, oxide ceramics, carbide ceramics or nitride ceramics.

[025] As indicated above, the surface of the substrate may be of any geometric properties. The surface may for example be at least essentially smooth. The surface may also be rough to any degree as long as it allows for the deposition of a selected photocatalytic matter and selected oxidisable matter. Where desired, the roughness of the surface may be altered. As an illustrative example, a metal oxide or metalloid oxide surface, e.g. a silicon oxide surface, may be ground by means of sand paper (Ferrari, M., et al. Applied Physics Letters (2006) 88, 203125-1 -203125-3). As a further illustrative example, the surface may be etched (cf. e.g. Cao, M. et al., J. Phys. Chem. B (2006) 110, 26, 13072-13075), for example using NaOH, KOH, a mixture of HF, HNO₃ and ethanol, a "buffered" HF solution containing NH₄F, or by ion bombardment using reactive ion etching, hi typical embodiments the surface is at least essentially homogenous. In some embodiments the surface is furthermore at least essentially flat. The surface may be polar or apolar, e.g. hydrophilic or hydrophobic. It may for instance be of different, similar or of the same hydrophobic properties when compared to the properties of the hydrophobic oxidisable matter used in the method of the present invention. [026] The method of the invention includes providing a substrate with a surface as described above and patterning the surface of the substrate such that a plurality of accessible surface areas is defined. Patterning the surface of the substrate usually includes selecting thereon a plurality of areas. On the plurality of surface areas photocatalytic matter is to be deposited as described below. The selected plurality of areas may include areas of any dimension and size. Some or all of the respective areas may be identical, similar or different in size and shape. In some embodiments all areas of the plurality of surface areas are identical. In some embodiments each area of the plurality of surface areas is of a maximal width in the plane of the surface that is that is below about 2 cm. As an example, the maximal width in the plane of the surface may be selected in the range of about 0.1 μm to about 5 cm, such as the range of about 1 μm to about 1 cm or the range of 10 μm to about to about 10 mm, for instance the range of about 100 μm to about 2000 μm. As an illustrative example, the maximal width in the plane of the surface may be about 10 μm to about 500 μm. In some embodiments some or all areas of the plurality of surface areas may be of a uniform width in the plane of the surface. An area of the plurality of surface areas may for instance be of the shape of a circle when viewed from above the respective surface. In other embodiments a respective area may include any number of widths in the plane of the surface. An area of the plurality of surface areas may for instance be of the shape of an egg, letters V, U, X or H, a triangle, a rectangle, a square, or any oligoedron. In some embodiments the areas of the plurality of surface areas define a micro pattern. In some embodiments any number of these areas, including all areas of the plurality of surface areas, is connected to form a continuous pattern, hi other embodiments any number of separate areas is arranged in such a way that as a whole they appear as a pattern.

[027] Patterning the surface of the substrate may furthermore include the use of additional matter in order to distinguish the selected plurality of areas from the remaining area of the surface. As an example, the remaining surface of the substrate may be covered with a mask, such as a photomask. It may in some embodiments be desired to select a photomask with an elastomeric film/coating of a selected thickness. Such a selection may for example be desired in order to improve the resolution of depositing photocatalytic matter on the surface of the substrate. An elastomeric film is likely to improve the contact between the mask and substrate and to minimize the diffusion of photocatalytic material between mask and substrate. It may furthermore be desired to apply additional pressure to further improve the contact. As another example, a photoresist may be deposited on the remaining surface of the substrate (cf. Fig. 2B for a graphic illustration). As yet a further example a plurality of stamps may be positioned above the plurality of accessible surface areas.

[028] The method of the invention further includes depositing only on the plurality of accessible surface areas photocatalytic matter. The term "photocatalytic matter" as used herein refers to any matter that fulfils the following two conditions. Firstly, photocatalytic matter is capable of catalysing a chemical reaction, such as an oxidation. Secondly, this capability is altered when exposed to electromagnetic radiation such as light. Photocatalytic matter may for instance be inactive when not exposed to electromagnetic radiation, but its capability of catalysing a chemical reaction is accelerated or induced upon being exposed to electromagnetic radiation. Photocatalytic matter may also be capable of catalysing a chemical reaction when not exposed to electromagnetic radiation, but the respective capability is partially or completely lost upon exposure to electromagnetic radiation. In typical embodiments, the photocatalytic matter becomes capable of catalysing a chemical reaction once exposed to electromagnetic radiation.

[029] A respective chemical reaction typically results in degrading chemical compounds and/or biological material. For the purpose of the method of the present invention the photocatalytic matter should at least be capable of assisting or starting a chemical reaction that can be exploited to degrade a desired hydrophilic compound (see below). For this purpose there is in some embodiments no additional reagent required, in particular in embodiments where the photocatalytic matter catalyses a degradation reaction itself (see the Examples below for an illustration). As an illustrative example, where titanium dioxide is used as the photocatalytic matter, an exposure to light, in particular UV light, causes the generation of active oxygen as a result of a photo redox reaction. The active oxygen is capable of oxidising matter in contact with or vicinity to the titanium dioxide. A standard method used in the art to assess the photocatalytic activity of matter of interest includes bringing 4-nitrophenol or rhodamine in vicinity or contact to the matter of interest, irradiating with e.g. UV light, and monitoring or determining the degradation of 4- nitrophenol or respectively rhodamine. Another standard method includes contacting water with the photocatalytic matter

[030] Any photocatalytic matter may be used in the method of the present invention that is capable of causing selected oxidisable matter to be at least essentially degraded (see below). The photocatalytic matter may for instance comprise a single photocatalytic compound, a mixture of photocatalytic compounds or a composite material of compounds that possesses photocatalytic activity. Two illustrative examples of a photocatalytic compound are a metal oxide and a metal sulphide. Examples of a metal oxide include, but are not limited to, a titanium oxide, a tin oxide, a lanthanum oxide, a tantalum oxide, a gadolinium oxide, a tungsten oxide, a nickel oxide, a copper oxide, a niobium oxide, a ruthenium oxide, a cerium oxide and any combination thereof. As three illustrative examples, a titanium oxide, in the following also abbreviated as TiO_x (in which x is typically 1 or 2), may be titanium dioxide, TiO₂ (in e.g. anatase or rutile forms), a niobium oxide may be Nb₂O₅, and a tantalum oxide may be Ta₂O₅. Three illustrative examples of a metal sulphide are zinc sulphide, ZnS, molybdenum sulphide, MoS₂, and cadmium sulphide, CdS. An illustrative example of a composite material of compounds that possesses photocatalytic activity is a mixed oxide of at least two metals. Examples of a mixed oxide of at least two metals include, but are not limited to, a zirconium/titanium oxide, a tantalum/titanium oxide, a silver/chromium oxide, a silver/molybdenum oxide, a silver/manganese oxide, a silver/tungsten oxide, a potassium/ cerium/tantalum oxide, a potassium/cerium/niobium oxide.

[031] The photocatalytic matter may be of any wettability. It may for example be of the same or a different wettability when compared to the surface of the substrate as provided in the method of the invention. In some embodiments the photocatalytic matter is hydrophilic.

[032] Where desired, the photocatalytic matter may also include a cocatalyst molecule such as platinum, palladium, ruthenium a ruthenium oxide, an iridium oxide or a nickel oxide. Likewise, a dopant such as iron, palladium or a platinum complex may be used where desired. Those skilled in the art will be aware of the fact that the photocatalytic activity of respective matter, e.g. a metal oxide, may to any degree depend on the state and form of the matter used, including the presence of surface defects. Gong et al. {Nature Materials (2006) 5, 665-670) have for instance characterised the atomic steps on the surface of anatase TiO₂, which may be used as the photocatalytic matter in a method of the present invention, and determined the stabilities of the respective oxide steps.

[033] The photocatalytic matter may be deposited by any means. In embodiments where the photocatalytic matter is a metal oxide or a mixture of metal oxides, it may for example be deposited by flame hydrolysis deposition (FHD), plasma enhanced chemical vapour deposition (PECVD), inductive coupled plasma enhanced chemical vapour deposition (ICP- CVD) or the sol-gel method. In some embodiments the photocatalytic matter is for example deposited by means of sputtering. In some embodiments the photocatalytic matter is deposited by means of the sol-gel process. As an illustrative example, a titanate sol may be generated by hydrolysis of tetrabutyl-titanate or tetrapropyl-titanate. Any suitable protocol, such as sol-gel protocols using acid-catalysed, base-catalysed and two-step acid-base catalysed procedures may be followed. In some embodiments the photocatalytic matter is deposited by means of chemical vapour decomposition. The respective deposition process, such as sputtering, a sol-gel process or a chemical vapour decomposition coating process used in the present invention can be performed according to any protocol.

[034] The photocatalytic matter deposited according to the method of the present invention may form any topography. It may for instance be deposited in form of a layer. A respective layer may be of any desired thickness. In typical embodiments, a respective thickness is selected in the range between about 1 and about 1000 nm, such as for example, 1.5 nm. In some embodiments the oxidisable matter forms a film on the surface. In one embodiment a respective film is a monolayer.

[035] Depositing the photocatalytic matter only on the plurality of accessible surface areas may be achieved by any means. Numerous methods of selectively depositing matter on a surface are established in the art. As an example, microcontact printing, microfluidic patterning, microfluidic lithography, cleaved edge overgrowth, or shadowed evaporation may be used. As a further example, a photoresist may be used in combination with e.g. lithography (involving irradiation with visible light, UV light or X-ray, including the use of a laser, with an ion beam, with an electron beam, or a scanning probe). In this way the remaining surface may be covered with a photoresist (see Fig. 2B, steps IIA and IIB). Following deposition of the photocatalytic matter (see Fig. 2B, step IIC), an exposure to an elevated temperature may cause the decomposition of the photoresist (see Fig. 2B, steps IIA and IIB), thus removing the photocatalytic matter in contact therewith ("lift-off). As a result, photocatalytic matter is removed from the remaining surface area(s). hi other embodiments an electron beam, fast iron bombardment, or laser microstructuring may be used to selectively remove photocatalytic matter from any area of the surface that is not selected or where it is not desired. As yet another example, a mask, such as a photomask, may be used both when patterning the surface of the substrate and when depositing photocatalytic matter, e.g. by means of sputtering (see above). A respective mask may cover the remaining surface of the substrate, thus preventing the deposition of photocatalytic matter thereon. A method of such an embodiment may include first covering the remaining surface of the substrate with a mask and subsequently depositing the photocatalytic matter on the surface. Thereby photocatalytic matter is deposited only on the plurality of accessible surface areas.

[036] The present method of the invention further includes depositing oxidisable matter on the entire surface. Any oxidisable matter may be used that can be deposited on the selected plurality of surface areas and that is capable of at least essentially withstanding a selected exposure to electromagnetic radiation that is sufficient to cause the photocatalytic matter to catalyse the oxidation of the oxidisable matter (see below). The oxidisable matter may for example be at least essentially inert to such an exposure of electromagnetic radiation. Furthermore, the oxidisable matter is of wettability that differs from the wettability of the photocatalytic matter. It may for instance be of a lower wettability for water when compared to the photocatalytic matter. As an illustrative example, the oxidisable matter may be characterised by an advancing contact angle (see below) for water that is at least 5° higher or 5° lower than the advancing contact angle for water of the photocatalytic matter. As an example, the oxidisable matter may have an advancing contact angle for water that is 10° higher than the advancing contact angle for water of the photocatalytic matter. As a further example, the oxidisable matter may have an advancing contact angle for water that is 10° lower than the advancing contact angle for water of the photocatalytic matter. In some embodiments the oxidisable matter is hydrophobic.

[037] Hydrophobic ("water-fearing") matter, has a tendency to separate from water. In contrast thereto, hydrophilic ("water-loving") matter generally contains molecules which can form dipole-dipole interactions with water molecules and thus have a high wettability for water (see also below). Usually hydrophobic matter is apolar and possesses an even distribution of electron density. A related term is the indication lipophilic ("fat-loving"). Lipophilic matter attracts non-polar organic compounds, such as oils, fats, or greases. It is understood that the terms "hydrophobic" and "lipophilic" are not synonymous. For example perfluorocarbon compounds are both hydrophobic and oleophobic, i.e. lack an affinity for oils. Such compounds accordingly have a tendency to separate from both water and hydrocarbons (though the latter to a lesser extent than from water).

[038] It is understood that the term "hydrophobic matter" refers to the state of respective matter after it has been deposited onto the surface. Before or during the process of depositing, the respective matter may in some embodiments be at least partially polar or include polar moieties. As an example, a molecule with a functional group containing a polar bond may provide apolar matter by a chemical reaction of the functional group with the surface. It is furthermore a known fact that the wettability of matter may change upon depositing and that from hydrophobic or hydrophilic characteristics of matter not necessarily a conclusion with respect to the hydrophobicity of a coating of such matter can be drawn. Accordingly, hydrophobic surfaces can be obtained by depositing onto the surface a material that is intrinsically hydrophilic. As an illustrative example, from poly(hydroxybutyrate-co- hydroxyvalerate), a hydrophilic material, a hydrophobic surface can be formed by electrospinning (see e.g. Zhu, M., et al., J. Mater. Sd. (2006) 41, 12, 3793-3797).

[039] Suitable oxidisable matter may for example include a wax such as paraffin wax, a fat (e.g. grease), an oil, a fatty acid, a silane, including an organofunctional silane such as a haloalkylsilane (see Fig. 3 for examples), a siloxane, a perfluoroalkane, a silazane, a stannane (in particular a tin-organic compound), a polymer such as a polysiloxane (silicone) and a composite of a polymer and inorganic particles.

[040] Typically, a silane used in a method according to the present invention includes at least one Si-Cl or Si-OR' bond, wherein R' may be any aliphatic, cycloaliphatic, aromatic, arylaliphatic, or arylcycloaliphatic moiety. As an illustrative example, a suitable silane may be a compound of the general formula (I): R^SiX-i-_m. In this formula m is an integer between 1 and 3. R¹ is an aliphatic, cycloaliphatic, aromatic, arylaliphatic, or arylcycloaliphatic hydrocarbyl group. In embodiments where m>l each R¹ moiety is independently selected, and X is an alkoxy group or Cl.

[041] As an illustrative example, in some embodiments a respective silane is a monoalkyltrichlorosilane (m=l) of general formula (Ia):

As indicated above, in this formula R¹ is an aliphatic, cycloaliphatic, aromatic, arylaliphatic, or arylcycloaliphatic hydrocarbyl group. Examples of a respective silane include, but are not limited to, trichloroethylsilane (Chemical Abstracts No. 115-21-9), trichlorooctylsilane (Chemical Abstracts No. 5283-66-9), trichlorocyclohexylsilane (CAS No. 98-12-4), (3,4,5,6- tetrafluoro-o-phenylene)bis[trichlorosilane] (CAS No. 4731-43-5), [5-([l,l'-biphenyl]-4- yloxy)pentyl]trichlorosilane (CAS No. 908373-00-2), trichloro[3-(2-naphthyl)propyl]-silane (CAS No. 18081-03-3), trichloro[[(triphenylsilyl)methyl]methyl]-silane (CAS No. 905601- 03-8), trichloro(2E)-2-pentenyl-silane (CAS No. 894071-79-5), trichloro(3-tricyclo- [3.3.1.13,7]dec-l-ylρropyl)-silane (CAS No. 52057-58-6), trichloro[2-(2-furyl)ethyl]silane (CAS No. 4607-99-2), trichloro[2,2^I:5^l,2":5^ll.2^III:5¹¹¹. 2""-quinquethiophen]-5-yl-silane (CAS No. 895570-04-4), trichloro(9-methyl-2-pentacenyl)-silane (CAS No. 895569-95-6), 1,10- decanediylbis[trichlorosilane] (CAS No. 52217-62-6) and trichloro[5-(trimethylsilyl)pentyl]- silane (CAS No. 892395-39-0). [042] As a further illustrative example, in some embodiments a respective silane is a dialkyldichlorosilane (m=2) of general formula (Ib):

Cl R¹— Si-Cl

R¹ As indicated above, in this formula R¹ and R¹ are independently selected aliphatic, cycloaliphatic, aromatic, arylaliphatic, or arylcycloaliphatic hydrocarbyl groups. Examples of a respective silane include, but are not limited to, dichlorodimethylsilane (CAS No. 75- 78-5), dichloromethylphenylsilane (CAS No. 149-74-6), dichloro(4-fluorophenyl)methyl- silane (CAS No. 1422-90-8), dichloroethenyl(phenylethynyl)-silane (CAS No. 95598-23-5), dichloromethyl[4-(phenylmethoxy)phenyl]silane (CAS No. 907586-51-0), dichloroethyl(4- methoxyphenyl)-silane (CAS No. 130952-94-2), dichloro[2-(3,5-dimethyltricyclo- [3.3.1.13,7]dec-l-yl)ethyl]methyl-silane (CAS No. 95601-39-1), dichloro[5-(l,l- dimethylethyl)-2-ethylidenecyclohexyl]methylsilane (CAS No. 130839-02-0), chloro[l- (dichloromethylsilyl)ethyl]dimethylsilane (CAS No. 95111-23-2) and l,3-bis[2- (dichloromethylsilyl)ethyl]-l,l,3,3-tetramethyldisiloxane (CAS No. 909864-81-9).

[043] As a further illustrative example, in some embodiments a respective silane is a trialkylmonochlorosilane (m=3) of general formula (Ic):

Cl R¹-Si-R¹"

R¹'

As indicated above, in this formula R¹, R¹ and R¹ are independently selected aliphatic, cycloaliphatic, aromatic, arylaliphatic, or arylcycloaliphatic hydrocarbyl groups. Examples of a respective silane include, but are not limited to, chlorotrimethylsilane (CAS No. 75-77- 4), chlorodecyldimethylsilane (CAS No. 38051-57-9), chlorotriphenylsilane (CAS No. 76- 86-8), trans- l-chloro-4-(l,l-dimethylethyl)-l-methyl-silacyclohexane (CAS No. 38109-31- 8), chloro(3-cycloρenten-l-ylmethyl)dimethylsilane (CAS No. 88710-89-8), chlorocyclo- hexyldiphenylsilane (CAS No. 76814-99-8), chloro-9H-fluoren-9-yl-bis(l-methylethyl)- silane (CAS No. 146086-17-1), (Moro[l l-[[(lJ-dimethyleihyl)dimethylsilyl]oxy]iindecyl]- dimethylsilane (CAS No. 910036-24-7), 5,7-dicWoro-5-methoxy-3,3,7-trimethyl-2-oxa- 3,5,7-trisilaoctane (CAS No. 146335-55-9) and l-chloro-l-heptyl-4-[2-(3,4,5-trifluoro- phenyl)ethyl]silane (CAS No. 220406-36-0).

[044] In some embodiments a respective silane is a haloalkylsilane. Such a haloalkylsilane may for instance be a fluoroalkylsilane. In some embodiments a respective fluoroalkylsilane is of general formula (II)

wherein n is an integer between 0 and 10. R to R are independently selected from the group consisting of H, F, Cl, aliphatic, cycloaliphatic, aromatic, arylaliphatic, and arylcycloaliphatic hydrocarbyl groups. At least one of R² to R⁶ is or includes F, and if n =0 at least one of R² to R⁴ is or includes F. R⁷ to R⁹ are independently selected aliphatic, cycloaliphatic, aromatic, arylaliphatic, or arylcycloaliphatic hydrocarbyl groups. Examples of a respective haloalkylsilane include, but are not limited to, triethoxy(heptafluoro- propyl)silane (Chemical Abstracts No. 874906-86-2), tributoxy(2,2-difluoroethyl)silane (Chemical Abstracts No. 4168-06-3), (2,2-difluoroethyl)trimethoxysilane (CAS No. 994-46- T), trimethoxy(l,l,2,2-tetrafluoroethyl)silane (CAS No. 356-49-0), trimethoxy(nonafluoro- butyl)-silane (CAS No. 84464-03-9), trimethoxy(undecafluoropentyl)silane (CAS No. 84464- 04-0), trimethoxy(pentadecafluoroheptyl)silane (CAS No. 84464-06-2), trimethoxy(trideca- fluorohexyl) silane (CAS No. 84464-05-1), (heptadecafluorooctyl)trimethoxysilane (CAS No. 88101-77-3), (heptafluoropropyl)trimethoxysilane (CAS No. 129051-17-8), 3,3,7,7- tetramethoxy-4-[l,2,2,2-tetrafluoro-l-(heptafluoropropoxy)ethyl]-6-[2,3,3,3-tetrafluoro-2- (heptafluoropropoxy)propyl]-2,8-dioxa-3,7-disilanonane (CAS No. 135179-25-8), tri- methoxy(pentatriacontafluoroheρtadecyl)silane (CAS No. 864979-41-9) and 7-[2-(2- aminoethoxy)ethoxy]-7-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)-3,6,8,l l-tetraoxa-7- silatridecane-l,13-diamine (CAS No. 887651-71-0).

[045] In some embodiments a respective fluoroalkylalkylsilane is of general formula (IH)

wherein n is an integer between 0 and 10. R to R are independently selected from the group consisting of H, F, Cl, aliphatic, cyclo aliphatic, aromatic, arylaliphatic, and arylcycloaliphatic hydrocarbyl groups. At least one of R² to R⁶ is or includes F, and if n =0 at least one of R² to R⁴ is or includes F. R⁷ to R⁹ are independently selected aliphatic, cycloaliphatic, aromatic, arylaliphatic, or arylcycloaliphatic hydrocarbyl groups. Examples of a respective haloalkylsilane include, but are not limited to, diethoxy(trifmoro- methyl)methylsilane (CAS No. 167408-24-4), dimethoxybis(trifluoromethyl)silane (CAS No. 173162-24-8), diethoxy[2,2,2-trifluoro-l,l-bis(trifluoromethyl)ethyl](trifiuoroethenyl)- silane (CAS No. 841313-62-0), dimethoxymethyl(2,2,2-trifluoro-l-methylethyl)silane (CAS No. 84442-94-4), (1,3,3,4,4, 5,5,6,6,7,7,8,8,9,9,9-hexadecafluorononyl)dimethoxymethyl- silane (CAS No. 879495-27-9), diethoxyethyl(3,3,4,4,4-pentafluorobutyl)-silane (CAS No. 144210-70-8), diethoxymethyl(2,2,2-trifluoro-l-methylethyl)silane (CAS No. 84442-93-3), (2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9, 9-heptadecafluorononyl)dimethoxymethylsilane (CAS No. 88123-40-4), ethyldimethoxy(tridecafluorohexyl)silane (CAS No. 146847-67-8), dimethoxy- methyl(2,2,3,3,4,4,5,5,6,6,7, 7,8,8,9,9,10,10,10-nonadecafluorodecyl)silane (CAS No. 143316-76- 1 ), 3,10-dimethoxy-3 , 10-bis(nonafluorobutyl)-2, 11 -dioxa-6-thia-3 , 10-disilado- decane (CAS No. 190390-92-2), dimethoxybis(nonafluorobutyl)silane (CAS No. 198219-88- 4), dimethoxymethyl(2,2,3,3,4,4,5,5,6,6,7,7,7-tridecafluoro-l-methylheρtyl)silane (CAS No. 339286-25-8), diethoxy(pentafiuorophenyl)(trifluoroethenyl)silane (CAS No. 561069-06-5), dimethoxymethyl(2,2,3 ,3 ,4,4,5,5,6,6,7,7,7-tridecafluoro- 1 -methyleneheptyl)silane (CAS No. 339286-26-9), (heneicosafluorodecyl)methylbis[(l-methylethenyl)oxy]silane (CAS No. 634911-27-6), diethoxy(pentafluoroρhenyl)(trifluoromethyl)silane (CAS No. 841313-54-0), diethoxybis(tridecafluorohexyl)silane (CAS No. 841313-59-5) and (1,3,3,4,4,5,5,6,6,7,7, 8,8,9,9,9-hexadecafluorononyl)dimethoxymethyl-silane (CAS No. 879495-27-9).

[046] In some embodiments a respective fluoroalkylsilane is of general formula (FV)

wherein n is an integer between 0 and 10. R² to R⁶ are independently selected from the group consisting of H, F, Cl, aliphatic, cycloaliphatic, aromatic, arylaliphatic, and arylcycloaliphatic hydrocarbyl groups. At least one of R² to R⁶ is or includes F, and if n =0 at least one of R² to R⁴ is or includes Fl. R⁷ to R⁹ are independently selected aliphatic, cycloaliphatic, aromatic, arylaliphatic, or arylcycloaliphatic hydrocarbyl groups. Examples of a respective haloalkylsilane include, but are not limited to, methoxydimethyl(pentadeca- fluoroheptyl)silane (CAS No. 855774-07-1), ethoxydimethyl(trifluorovinyl)silane (CAS No. 5674-84-0), ethoxytris(trifluoromethyl)silane (CAS No. 156514-86-2), ethoxydimethyl- (tridecafluorohexyl)silane (CAS No. 178317-29-8), dodecyloxy)methyl(l-methylethyl)- (pentafluorophenyl)silane (CAS No. 75943-76-9), ethoxydimethyl(3,3,3-trifluoropropyl)- silane (CAS No. 650-29-3), dibutylethoxy(3,3,3-trifluoropropyl)silane (CAS No. 1536-22-7), ethoxymethylbis(3,3,3-trifluoropropyl)silane (CAS No. 1549-63-9), 6-[[(l,l-dimethyl- ethyl)diphenylsilyl]oxy]-3-[[(3,3,4,4,5, 5,5-heptafluoropentyl)bis(l-methylethyl)silyl]oxy]- eicosanal (CAS No. 910248-04-3), 7-[3-cyclohexyl-l-[[(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10, 11,1 l,12,12,12-heneicosafluorododecyl)bis(l-methylethyl)silyl]oxy]propyl]-12-[dimethyl(l- methylethyl)silyl]-8-methyl-indolizino[l,2-b]quinolin-9(l lH)-one (CAS No. 340129-80-8) and l,l,l,15,15,15-hexafluoro-4,12-dimethyl-4,12-bis(3,3,3-trifluoropropyl)-5,8,l l-trioxa- 4,12-disilaρentadecane (CAS No. 19923-62-7).

[047] Any aliphatic, cycloaliphatic, aromatic, arylaliphatic or arylcycloaliphatic hydrocarbyl group included in the moieties R² to R⁹ in formulas (II) to (V) may include 1-3 heteroatoms, i.e. atoms that differ from carbon, selected from the group consisting of N, O,

S, Se and Si. Any two aliphatic hydrocarbyl groups of moieties R² to R⁶ in formulas (II) to

(V) may furthermore be connected so as to define an aliphatic or aromatic ring structure.

[048] Further examples of a suitable haloalkylsilane include, but are not limited to, chloropropylmethyldimethoxysilane, triethoxychlorobutylsilane, trichlorochloropropylsilane, dimethylchlorochloropropylsilane, (dichloromethyl)trimethylsilane, trimethyl(trichloro- methyl)silane, fluorooctylmethyldimethoxysilane, triethoxy(heptafluoropropyl)silane, dime- thylbis( 1 , 1 ,2,2-tetrafluoroethyl)-silane, (2-chloro- 1 , 1 ,2-trifluoro ethyl)trimethylsilane, dimethyl^ , 1 ,2,2,3 ,3 ,4,4-octafluorobutyl)(l , 1 ,2,2-tetrafluoroethyl)-silane, diethylbis(heptafluoro- propyl)silane, 4,4-diethyl-2,3-difluoro-l,l,l-triphenyl-l,4-disilahex-2-ene, trimethyl[l, 2,2,2- tetrafluoro- 1 -(trifluoromethyl)ethyl]-silane, ethynylbis(fluoromethyl)methyl-silane, (1,1 -di- fluoropropyl)dimethylphenylsilane, 5-chloro- 1 , 1 -dimethyl-silacyclopent-2-ene, (2-chloro- 3,3,3-trifluoropropyl)diethoxymethyl-silane, trimethoxy(tridecafluorohexyl)-silane, triethoxy(pentafluorophenyl)-silane, (heptadecafluorooctyl)dimethyl[9-(tricMorosilyl)- nonyl]-silane, diethoxymethyl(2,2₅2-trifluoro-l -methylethyl)-silane, triethoxy(pentafluoro- phenyl)silane, triethoxy(nonacosafluorotetradecyl)-silane, 1,1,1 -trimethoxy-3 ,5,5,5-tetra- methyl-3-(nonafluorobutyl)-trisiloxane and l,l,l,5,5,5-hexamethyl-3-(3,3,3-trichloropropyl)- 3-[(trimethylsilyl)oxy]-trisiloxane.

[049] An illustrative example of a tin-organic compound is an alkyl stannane, such as tetrapropyl-stannane, bis[4-(l , 1 -dimethylethyl)phenyl]dimethyl-stannane, chloro(4-hexyl- phenyl)dimethyl-stannane, 6-(tributylstannyl)-3-pyridinamine or 3-methyl-6-(4-pyridinyl- methyl)-8-(tributylstannyl)-quinoline. A further illustrative example of a tin-organic compound is a haloalkylstannane, such as dimethylbis(pentafluoroethyl)-stannane, triethyl- (trifluoroethenyl)-stannane, triphenyl(trifluoroethenyl)-stannane, tributyl(pentafluoroethyl)- tin, tributyl(trichloromethyl)-stannane or tributyl(l,2-difluoro-2-iodoethenyl)-stannane.

[050] As an illustrative example of a perfluoroalkane, tetrafluoromethane gas may be deposited on the surface by means of atmospheric radio frequency glow-discharge plasma deposition. For this purpose a mixture of tetrafluoromethane and hydrogen can be used in a carrier gas such as helium (Kim, S.H., et al., Langmuir (2005) 21, 26, 12213-12217). As a further example, plasma deposition by electrical discharge of tetrafluoromethane gas may be used (e.g. Woodward, I.S., et al. Plasma Chem. Plasma Process (2006) 26, 507-516).

[051] As a further illustrative example, a plasma of a perfluoroalkane, such as octafluorocyclobutan (C₄F₈), hexafluoroethane (C₂F₆) or tetrafluormethane (CF₄), may be used to form a perfluoroalkane-poryrner and to deposit it onto the surface. A respective polymer of controllable thickness may for instance be deposited on a surface using an inductively coupled plasma reactive ion etcher equipment as described by Kolari &

Hokkanen (Journal of Vacuum Science & Technology, A: Vacuum, Surfaces, and Films (2006), 24(4), 1005-1011).

[052] As yet a further example, a haloalkylsilane, for instance of general formula (V) may be deposited onto the surface:

wherein n is an integer between 0 and 10. R² to R⁶ are independently selected from the group consisting of H, F, Cl, aliphatic, cycloaliphatic, aromatic, arylaliphatic, and arylcycloaliphatic hydrocarbyl groups. At least one of R² to R⁶ is or includes F or Cl, and if n =0 at least one of R² to R⁴ is or includes F or Cl. R⁷ to R⁹ are independently selected aliphatic, cycloaliphatic, aromatic, arylaliphatic, or arylcycloaliphatic hydrocarbyl groups. Examples of a respective haloalkylsilane include, but are not limited to, [1,1,2,3,4,4,4- heptafluoro-3-(trifiuoromethyl)butyl]trimethylsilane (CAS No. 71126-99-3), trimethyl- (l,l,3,3,3-pentafluoroρropyl)silane (CAS No. 62281-41-8), (2,3,3,4,4,4-hexafluorobutyl)- trimethylsilane (CAS No. 309-20-6), ethyl(heptafluoropropyl)methylvinylsilane (CAS No. 678-64-8), ethylbis(heptafluoropropyl)methylsilane (CAS No. 754-54-1), 4-fluoro-3- (trimethylsilyl)-pyridine (CAS No. 116922-61-3), (l-chloro-3,3,3-trifluoropropyl)trimethyl- silane (CAS No. 3550-30-9), 2,2,5,5-tetramethyl-3,4-bis(trifluoromethyl)-2,5-disilahexane (CAS No. 7651-92-5), l-ethyl-4-fluoro-2-(l-naphthalenyl)-5-(trimethylsilyl)-lH-imidazole (CAS No. 906477-20-1), (2,6-difluoro-4-pentylphenyl)trimethylsilane (CAS No. 138871-45- 1) trimethyl[2,3,5,6-tetrafluoro-4-[[(tetrahydro-2H-pyran-2-yl)oxy]methyl]phenyl]-silane (CAS No. 122936-64-5), (3-chloropropyl)methyldipentylsilane (CAS No. 890711-62-3), (3,4-dichlorobutyl)ethyldimethylsilane (CAS No. 1591-13-5), (l-bromo-3,3,3-trichloro- l,2,2-trifluoropropyl)triethylsilane (CAS No. 2710-76-1), trimethyl(l,3,3-trichloropropyl)- silane (CAS No. 80058-72-6) and dimethyl(trichloromethyl)(l,l,2-trimethyl-2-proρenyl)- silane (CAS No. 81484-93-7).

[053] As another example, a siloxane may be deposited onto the surface. This may for instance be achieved by spin-coating a long-chain alkyl- or alkenyltrichlorosilane, such as octadecyltrichlorosilane, dodecyltrichlorosilane or ω-undecenyltrichlorosilane, onto the surface as described by e.g. Franzka et al. (Thin Solid Films (2005) 488, 124-131).

[054] As yet a further example, a polymer such as a poly(alkyl)pyrrole, poly(hydroxy- butyrate-co-valerate), phenyltris(trifluoromethyl)silane homopolymer (CAS No. 205814-01- 3) or polytetrafluoroethylene may be used as respective oxidisable matter. As an illustrative example, an electrochemical polymerisation of an alkylpyrrole (such as 1-n- octadecylpyrrole) may be carried out on the surface (see Yan, H. et al. Angew. Client. Int. Ed (2005) 44, 3453-3456). As a further illustrative example, by means of glow discharges a polymerisation of a perfluorocarbon compound such as tetrafluoro ethylene, may be carried out. By way of continuous plasma depositions, an obtained polymer such as polytetrafluoroethylene is deposited on a provided surface (see Favia, P., et al. Surface and Coatings Technology (2003), 169 ill '0, 609-612). As yet another example, a solution of poly(hydroxybutyrate-co-valerate) may be deposited onto a surface by means of electro spinning (Zhu, M., et al., 2006, supra). The deposition of other polymers on a surface is a standard technique well known in the art. As an illustrative example, polystyrene spheres may be deposited (Gu et al., 2002, supra).

[055] An example of a composite of a polymer and inorganic particles that may be used as oxidisable matter is a microsphere of calcium carbonate and polyvinylidenedifluoride

(PVDF). By dissolving PVDF in dimethyl formamide, adding 2 % of tridecafluorooctyl- triethoxysilane and a trace amount of diluted acetic acid, and subsequently adding calciumcarbonate particles in a ratio of 1:1 (PVDF/CaCO₃) a coating solution of polymer microspheres is obtained (Yan, L., et al., Journal of Materials Science Letters (2003) 22, 1713-1717). A further example of a composite of apolymer and inorganic particles are silica nanoparticles coated with a fiuorocarbon polymer. Such nanoparticles can be deposited on a surface by first dip coating the surface with silica nanoparticles and subsequently coating the surface with a respective polymer, such as FC735 (Ferrari, M., et al., 2006, supra).

[056] The oxidisable matter may be deposited by any means. Illustrative examples have already been given above. Furthermore, depending on the nature of the oxidisable matter used, other means of depositing the same may be applied, such as for example spin-coating, dip-coating, flame hydrolysis deposition, chemical vapour deposition (including plasma enhanced chemical vapour deposition, inductive coupled plasma enhanced chemical vapour deposition or hot filament chemical vapour deposition), physical vapour deposition (including plasma-assisted physical vapour deposition and electron beam physical vapour deposition), atomic layer deposition (including plasma-assisted atomic layer deposition), dense plasma focus deposition, pulsed laser deposition, the sol-gel process, thermoreactive diffusion deposition, or thermal diffusion deposition, where applicable. It may in some embodiments be desired to generate a thin layer of oxidisable matter on the substrate surface, for example a film. It can generally be expected that thin layer of oxidisable matter will produce a better quality/accuracy in patterning because the radicals generated from photocatalytic matter can only reach a limited distance.

[057] Accordingly, the oxidisable matter provides the entire surface, including the plurality of accessible surface areas, with a wettability that differs from the wettability of the photocatalytic matter. In some embodiments it also provides the entire surface with a wettability that differs from the wettability of the surface of the substrate, i.e. as provided before depositing any matter thereon. Thereby a surface with an at least essentially uniform wettability for water is produced. The wettability of the surface differs from the wettability of the photo catalytic matter, and in some embodiments also from the wettability of the surface of the substrate as such. As an illustrative example, the oxidisable matter may be hydrophobic, including for example superhydrophobic, for instance with a contact angle for water of more than 150°. Such hydrophobic oxidisable matter renders the entire surface, including the plurality of accessible surface areas, hydrophobic, in particular more hydrophobic than the photocatalytic matter. In such embodiments, a surface with a low wettability for water is thereby produced. A surface pattern may nevertheless in some embodiments be detectable, for example in terms of the topography of the surface.

[058] A common way of defining the wettability of a surface is the contact angle (also termed wetting angle) between a water droplet in thermal equilibrium on a horizontal surface, which is generally smooth and homogeneous, typically surrounded by a gas such as air. In this respect, a person skilled in the art will be aware of the fact that for contact angles above 90° an increasing roughness of a surface typically increases the hydrophobicity. For contact angles below 90° an increasing roughness of a surface typically increases the hydrophilicity. Where a water droplet is used, the contact angle θ is given by the angle between the interface of water droplet and the horizontal surface. Such a contact angle θ is a thermodynamic variable that depends on the interfacial tensions of the surfaces involved. It reflects the balance of forces exerted by an attraction of molecules within the water phase to each other versus the attraction or repulsion those droplet molecules experience towards the surface molecules.

[059] The most commonly used technique of determining the contact angle is the so called static or sessile drop method. The measurement usually involves a successive addition of water droplets until a plateau in the contact angle is reached. The value at a respective plateau is called the advancing contact angle. A further value that may be used to characterise a surface is the so called receding contact angle. It is measured when the contact point of a liquid droplet on a surface begins to change upon retracting the liquid of the droplet. The difference between advancing and receding contact angles can be taken as an indication as to the non-uniformity of the chemical and/or physical nature of a surface. Further means of determining the contact angle include the Wilhemly Plate method, the Captive Air Bubble method, the Capillary Rise method, and the Tilted-drop measurement.

[060] A contact angle θ of zero degrees results in wetting, while a contact angle θ between about 0 and about 90 degrees results typically in spreading of a water droplet, in particular at values in the range below about 45 degrees. Contact angles θ greater than about 90 degrees indicate the fluid tends to bead or shrink away from the solid surface. In some embodiments the hydrophobic oxidisable matter provides the surface, including the selected area thereof, with a wettability for water that can be characterised by an advancing contact angle θ of about 50 degrees or higher, such as about 90 degrees or higher or at least about 100 degrees or higher. It is furthermore understood that the contact angle is an indication of the hydrophobicity of a surface as compared to other surfaces. A surface with a higher contact angle (with respect to water) can therefore generally be taken to be of higher hydrophobicity than a surface with a lower contact angle.

[061] hi some embodiments (see also below) it may be desired to perform a simultaneous electrochemical and contact angle measurement. For this purpose a so called

Wilhelmy balance is known in the art, which records the total force acting on a surface as the latter is being moved vertically (for further details see e.g. Wang, X., et al. Langmuir (2006)

22, 9287-9294).

[062] The present method of the invention further includes exposing the entire surface to electromagnetic radiation. The respective radiation may be selected within any range of wavelengths of the electromagnetic spectrum. If desired, one distinct wavelength or a set of distinct wavelengths may be selected, or one or more defined regions of the electromagnetic spectrum. Examples of regions of the electromagnetic spectrum that may be chosen include, but are not limited to, visible light, ultraviolet light or infrared light. Visible light corresponds to a wavelength range of about 400 to about 700 nanometers, ultraviolet light corresponds to a wavelength range of about 30 to about 400 nanometers and infrared light corresponds to a wavelength range of about 700 nanometers to about 1 millimeter, hi some embodiments a wavelength is for instance selected within the near UV (380 to 200 nm), while in other embodiments it is for instance selected within the far UV (200 to 10 nM). As an example, the wavelength may be selected to be 300 nm or shorter, for instance 254 nm or

248 nm. Where desired, such UV light may also be pulsed. An illustrative example of a means of providing UV light of a respective wavelength of 248 nm is a KrF laser.

[063] The electromagnetic radiation may be of any intensity and the exposure of any length as long as it is sufficient to render the photocatalytic matter capable of catalysing the oxididation of the selected oxidisable matter (see above). Those skilled in the art will be aware of the fact that the required exposure time will depend on the power of the electromagnetic radiation used, hi typical embodiments where UV light is used as electromagnetic radiation, the energy density is of at least 50 mJ/cm², such as for example of at least 100 mJ/cm². Accordingly, the photocatalytic matter catalyses the oxidation of such oxidisable matter that is in contact therewith (see above).

[064] As a result, oxidisable matter that is in contact with photocatalytic matter is removed from the plurality of surface areas. Accordingly, only the remaining area of the surface retains, at least essentially, the wettability provided by the oxidisable matter. As an illustrative example the remaining area of the surface remains hydrophobic in embodiments where hydrophobic oxidisable matter is used. In contrast thereto, the photocatalytic matter in the plurality of surface areas is being exposed. This is due to the fact that exposing the surface to electromagnetic radiation shows little or no impact on the oxidisable matter that is not in contact with the photocatalytic matter. In the absence of matter with the catalytic properties described above, oxidation, including degradation of the oxidisable matter by electromagnetic radiation is very slow, so that, if at all, marginal or insignificant effects on the oxidisable matter are observed. Typically the oxidisable matter remains even entirely unaltered.

[065] hi some embodiments exposing the entire surface to electromagnetic radiation renders the photocatalytic matter hydrophilic. After exposure to the electromagnetic radiation a respective hydrophobic property of the photocatalytic matter may for example be a wettability that can be characterised by an advancing contact angle θ of about 90 degrees or lower, such as about 50 degrees or lower or about 25 degrees or lower. The advancing contact angle may for example be selected in the range of about 0 degrees to about 25 degrees. As an illustrative example, titanium dioxide becomes superhydrophilic upon irradiation. This effect is thought to be the result of surface oxygen vacancies, generated by irradiation. These oxygen vacancies are thought to lead to the adsorption of water molecules. As already indicated above, the hydrophilicity of the surface generated by irradiation may however not last for extended periods of time. Titanium dioxide that has been irradiated is for example known to become less hydrophilic upon storage in the absence of an inert gas atmosphere. Freshly generated mesoporous titanium dioxide films have for example been found to show contact angles of 10-15 ° (Yu, J., et al., New J. Chem. (2002) 26, 607-613). However, after storage in the dark for 3 months, contact angels of about 60 ° were determined. Upon irradiation with a 15 W 365 nm UV lamp contact angels dropped to below 5 ° (ibid.).

[066] According to a further method of the present invention photocatalytic matter is deposited on the entire surface of the substrate. According to this method, oxidisable matter, as described above, is vapour coated on the entire surface. In this method of the invention the surface of the substrate is also patterned as explained above. In contrast to the method described above, only the plurality of accessible surface areas is exposed to electromagnetic radiation. As explained above, the photocatalytic matter catalyses the oxidation of oxidisable matter that is in contact therewith. The oxidisable matter is thereby removed from the plurality of surface areas. As in the method described above, the photocatalytic matter on these surface areas is exposed and the oxidisable matter on the remaining surface of the substrate is at least essentially preserved. Accordingly, in this method there is also a pattern of discriminative wettability formed.

[067] In some embodiments, a method according to the invention further includes depositing a substance only on the plurality of surface areas, where photocatalytic matter is deposited. Any desired substance may be deposited. The substance may for instance be hydrophilic or hydrophobic. The substance may be deposited by any means, for example using a plasma process or a sol gel process (see above for further examples). In some embodiments the respective substance is deposited after the entire surface has been exposed to electromagnetic radiation (see above).

[068] hi some embodiments hydrophobic matter may for example be deposited as described above. In other embodiments a hydrophilic substance may for example be deposited on the surface. Examples of a suitable hydrophilic substance include, but are not limited to, a polymer, e.g. a polymer obtained from ethylene oxide or from an acrylate, a polycarbonate, a polyimide, silica, a polysaccharide (including hyaluronan, dextran and cellulose) or a glycosaminoglycan. As an illustrative example, silica may be desposited by means of the sol-gel method, e.g. by hydrolysing an alkoxysilane such as tetraethoxysilane. Plasma deposition of polymerised silicate films may likewise be carried out for depositing a silicate on the surface (e.g. Vasallo, E. et al., Surface & Coatings Technology (2006) 200, 3035-3040). As a further illustrative example, a hydrogel may be formed on the plurality of accessible surface areas by disposing a pregel-solution and subsequent spin-coating as described by Jakobs and Hanein {Colloids & Surfaces A: Physiochem. Eng. Aspects (2006) 290, 33-40). As yet another example, a thin liquid film that can undergo dewetting in water may be deposited, which may for example include octyl p-methoxycinnamate and octylsilyl titanium dioxide particles (see abstract of Ruroda, A. et al., Journal of Oleo Science (2006) 55, 6, 277). Thereby a further dewetting pattern can be formed within the existing wettability pattern of the surface. [069] In some embodiments the substance may include a molecule with a linking moiety. A respective substance may for example include functional groups that allow for the covalent attachment of a target molecule such as a protein or a nucleic acid molecule. Any molecule with a reactive moiety that is capable of undergoing a reaction with a corresponding moiety of an analyte molecule may be used. As an illustrative example, a linking molecule may be an aliphatic compound with a backbone of 4 - 50 carbon atoms, of which some may be exchanged by N, O, Si or S atoms, and a reactive functional group. Examples of reactive functional groups include, but are not limited to, aldehydes, carboxylic acids, esters, imido esters, anhydrides, acyl nitriles, acyl halides, semicarbazides, acyl azides, isocyanates, sulphonate esters, sulfonyl halides, or aryl halides, which may for example react with an amino group of a capture molecule, or alkyl sulphonates, aryl halides, acrylamides, maleimides, haloacetamides or aziridines, which may for example react with a thio group of a capture molecule or a carboxylic acid, an anhydride, an isocyanate, a phosphoramidite, a halotriazine, an acyl halide, an acyl nitrile, an alkyl halide, an alkyl sulphonate or a maleimide, which may for example react with a hydroxy group of a capture molecule.

[070] As an example, a silane or stannane may be used as the respective substance, which includes a respective functional group, such as an aldehyde moiety, an amino moiety or a thiol moiety. In embodiments where the molecule with a linking moiety is a silane, it may for example be a monomethoxysilane, a dimethoxysilane, a trimethoxysilane, a monochlorosilane, a dichlorosilane or a trichloroysilane. The respective silane may for instance include, such as be terminated with, an aldehyde, an amine, an epoxy or an anhydride moiety. Illustrative examples of a silane with an aldehyde moiety include trimethoxysilylbutyraldehyde (Chemical Abstracts No. 501004-24-6), triethoxy- silylbutyraldehyde (Chemical Abstracts No. 88276-92-0), 4-(triethoxysilyl)-l,3- cyclopentanedicarboxaldehyde (Chemical Abstracts No. 88276-92-0), l,3-4-(diethoxy- ethylsilyl)-cyclopentanedicarboxaldehyde (CAS-No 18544-91-7), 3-(trimethoxysilyl)- hexanedial (CAS-No 17874-10-1), 3-(diethoxymethylsilyl)-propanal (CAS-No 88276-87-3), 2-(trimethoxysilyl)-propanal (CAS-No 88276-91-9), 2-(diethoxymethylsilyl)-propanal (CAS-No 88276-88-4), 2-[2-(triethoxysilyl)ethyl]-3-thiophenecarboxaldehyde (CAS-No 351055-24-8). Illustrative examples of a silane with an amine moiety include 1- (trimethoxysilyl)-methanamine (CAS-No 71408-48-5), (aminopropyl)methyldiethoxysilane (CAS-No 3179-76-8), [(diethoxymethylsilyl)methyl]amine (CAS-No 18186-77-1), amino- methyltriethoxysilane (CAS-No 18306-83-7), α-aminobutyltrimethoxysilane (CAS-No 36394-66-8) and l-l-(trimethoxysilyl)-propanamine (CAS-No 112309-66-7). Illustrative examples of a silane with a thiol moiety include 2-(trimethoxysilyl)-ethanethiol (CAS-No 7538-45-6), 2-(dimethoxymethylsilyl)-ethanethiol (CAS-No 14857-98-8), l-(triethoxysilyl)- 1,2-ethanedithiol (CAS-No 32318-39-1), l,l-dimethoxy-silacyclopentane-3 -thiol (CAS-No 35932-31-1), and 5-mercaptopentyltriethoxysilane (CAS-No 63392-36-9). A respective silane or stannane may be deposited by any means (see also above). The surface may for instance be exposed to a silane or stannane solution or a silane or stannane vapour. As an illustrative example, a solution of (3-aminopropyl)dimethoxysilane in ethanol can provide amino groups for the coupling to molecules such as proteins (Klose, T, et al., Colloids and Surfaces B: Biointerfaces (2006) 51, 1-9). As another illustrative example, a solution of triethoxysilylbutyraldehyde in toluene/0.1% acetic acid can provide aldehyde groups that can likewise be used for subsequent coupling (see the Examples below).

[071] As a further illustrative example, chlorine-doped polypyrrole may be electrochemically deposited onto the surface (Sanghvi, A. et al., Nature Materials (2005) 4, 496-502). Peptides, oligonucleotides or oligosaccharides etc. can then react with the chlorine-groups on the surface to provide a moiety that can specifically bind to target matter, e.g. analytes such as peptides, proteins, oligonucleotides, nucleic acids or polysaccharides. Respective peptides may be selected by means of phage display (ibid.).

[072] As yet another example, a polymer with reactive amino groups may be deposited on the surface such as N-(2-hydroxypropyl)methacrylamide copolymers containing 4- nitrophenyl ester (using the monomer N-meth-acryloylglycylglycine) or thiazolidine-2- thione groups (using 3-(6-methacrylamidohexanoyl)thiazolidine-2-thione or 3-(N- methacryloylglycylglycyl)thiazolidine-2-thione monomers). The obtained polymers are capable of reacting with amino groups of lysine residues of proteins (see Subr, V et al., Biomacromolecules (2006) 7, 122-130).

[073] The present inventors have found that generally little or no deposition of the respective substance occurs on the hydrophobic matter. As an illustrative example, where a silane is used as oxidisable matter and a dense film thereof is formed on the surface of the substrate, no surface hydroxyl group is available for depositing e.g. a further silane on the respective dense film. Accordingly, depositing the substance only on the plurality of surface areas, i.e. where photocatalytic matter is deposited, does usually not require any means that prevents the deposition of the substance on the remaining surface.

[074] In some embodiments the linking moiety is a receptor molecule for a target molecule such as a protein, a nucleic acid, a polysaccharide or any combination thereof. In such embodiments the linking moiety and the target molecule may define a specific binding pair. Examples of a respective receptor molecule include, but are not limited to immunoglobulin, a mutein based on a polypeptide of the lipocalin family, a glubody, a protein based on the ankyrin or crystalline scaffold, an avimer, the T7 epitope, maltose binding protein, the HSV epitope of herpes simplex virus glycoprotein D, the hemagglutinin epitope, and the myc epitope of the transcription factor c-myc, an oligonucleotide, an oligosaccharide, an oligopeptide, biotin, dinitrophenol, digoxigenin and a metal chelator (cf. also below). As an illustrative example, a respective metal chelator, such as ethylenediamine, ethylenediaminetetraacetic acid (EDTA), ethylene glycol tetraacetic acid (EGTA), diethylenetriaminepentaacetic acid (DTPA), N,N-bis(carboxymethyl)grycine (also called nitrilotriacetic acid, NTA), l,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA), 2,3-dimercapto-l-propanol (dimercaprol), porphine or heme may be used in cases where the target molecule is a metal ion. As an example, EDTA forms a complex with most monovalent, divalent, trivalent and tetravalent metal ions, such as e.g. silver (Ag ), calcium (Ca²⁺), manganese (Mn²⁺), copper (Cu²⁺), iron (Fe³⁺), cobalt (Co³⁺) and zirconium (Zr⁴⁺), while BAPTA is specific for Ca²⁺. In some embodiments a respective metal chelator in a complex with a respective metal ion or metal ions defines the linking moiety. Such a complex is for example a receptor molecule for a peptide of a defined sequence, which may also be included in a protein. As an illustrative example, a standard method used in the art is the formation of a complex between an oligohistidine tag and copper (Cu²⁺), nickel (Ni²⁺), cobalt (Co²⁺), or zink (Zn²⁺) ions, which are presented by means of the chelator nitrilotriacetic acid (NTA).

[075] As already mentioned above, the linking moiety, which may be included into a respective molecule (including a macromolecule) of the substance before, during or after the substance has been deposited on the surface, may be converted into another linking moiety. This may for example be desired to obtain a linking moiety that has a chosen degree of specifity for selected target matter. The linking moiety may for instance be reacted with a receptor molecule for a target molecule. The receptor molecule and the target molecule define a specific binding pair (see above and below). By a respective reaction a complex, such as a coordinative complex, or a covalent bond may be formed. By forming such a complex or bond the previous linking moiety is being converted into another linking moiety. As an illustrative example, a respective method of the present invention may include contacting the surface of the substrate with a receptor molecule for a target molecule (see also above). The receptor molecule is capable of interacting with the linking moiety, such that a complex between the receptor molecule and the linking moiety is formed. The formation of this complex may, in some embodiments, result in, or be part of, the formation of a covalent bond. As a result, the receptor molecule is immobilised on the plurality of surface areas via the linking moiety. The linking moiety has in turn been converted into another linking moiety.

[076] Aldehyde, amino or thiol groups may for example be reacted with a peptide, protein, oligosaccharide, an oligonucleotide or any other molecule that has a desired specifity for a selected target molecule (see e.g. Sanghvi et al., 2005, supra, for a specific example). The resulting moiety may for instance be a moiety that is known in the art as an "affinity tag". Examples of such moieties include, but are not limited to biotin, dinitrophenol, digoxigenin, oligohistidine, polyhistidine, an immunoglobulin domain, maltose-binding protein, glutathione-S-transferase (GST), calmodulin binding peptide (CBP), FLAG'- peptide, the T7 epitope (Ala-Ser-Met-Thr-Gly-Gly-Gln-Gln-Met-Gly), maltose binding protein (MBP), the HSV epitope of the sequence Gln-Pro-Glu-Leu-Ala-Pro-Glu-Asp-Pro- Glu-Asp of herpes simplex virus glycoprotein D, the hemagglutinin (HA) epitope of the sequence Tyr-Pro-Tyr-Asp-Val-Pro-Asp-Tyr-Ala and the "myc" epitope of the transcription factor c-myc of the sequence Glu-Gln-Lys-Leu-Ile-Ser-Glu-Glu- Asp-Leu.

[077] As a further illustrative example, a respective moiety may also be an antibody, a fragment thereof or a proteinaceous binding molecule with antibody-like functions. Examples of (recombinant) antibody fragments are Fab fragments, Fv fragments, single- chain Fv fragments (scFv), diabodies or domain antibodies (Holt, LJ., et al., Trends Biotechnol. (2003), 21, 11, 484-490). An example of a proteinaceous binding molecule with antibody-like functions is a mutein based on a polypeptide of the lipocalin family (WO 03/029462, Beste et al., Proc. Natl. Acad. ScL USA (1999) 96, 1898-1903). Lipocalins, such as the bilin binding protein, the human neutrophil gelatinase-associated lipocalin, human Apolipoprotein D or glycodelin, posses natural ligand-binding sites that can be modified so that they bind to selected small protein regions known as haptens. Examples of other proteinaceous binding molecules are the so-called glubodies (see WO 96/23879), proteins based on the ankyrin scaffold (Mosavi, L.K., et al., Protein Science (2004) 13, 6, 1435-1448) or crystalline scaffold (WO 01/04144) the proteins described in Skerra, J MoI. Recognit. (2000) 13, 167-187, and avimers. Avimers contain so called A-domains that occur as strings of multiple domains in several cell surface receptors (Silverman, J, et al., Nature Biotechnology (2005) 23, 1556-1561). Where desired, a modifying agent may be used that further increases the affinity of the respective moiety for any or a certain form, class etc. of target matter.

[078] In some embodiments, in particular where the substance comprises a molecule with a linking moiety, the method further includes immobilising target matter, such as a target molecule, on the plurality of surface areas. This may for example be achieved via the linking moiety, whether by way of formation of a complex or by means of a covalent bond. Any matter may be the target matter and any molecule may likewise be selected as a target molecule. As an illustrative example, target matter may be an analyte that is included in a sample, for example a sample derived from human or non-human animals, plants, bacteria, viruses, spores, fungi, or protozoa, or from organic or inorganic material of synthetic or biological origin. A respective analyte may for instance be a protein, a nucleic acid molecule, a solvent molecule, a pesticide molecule, a saccharide molecule, an allergen, a hormone, a virus or a cell.

[079] In some embodiments a detectable marker may be coupled to a molecule with a linking moiety. This may for instance be carried out to monitor the deposition of the respective molecule with a linking moiety. The available linking moieties may be reacted to any degree. Using a low concentration or amount of a respective marker, a selected percentage of linking moieties may for example remain available for a reaction with a target molecule or for a conversion to another linking moiety (see above). A respective marker compound may also be included in a reagent used for the conversion of a linking moiety to another linking moiety. Such a marker may be an optically detectable label, a fluorophore, or a chromophore. Examples of suitable labels include, but are not limited to, an organic molecule, an enzyme, a radioactive, fluorescent, and/or chromogenic moiety, a luminescent moiety, a hapten, digoxigenin, biotin, a metal complex, a metal and colloidal gold. Accordingly a radioactive amino acid, fluorescein isothiocyanate, 5,6-carboxymethyl fluorescein, Texas red, nitrobenz-2-oxa-l,3-diazol-4-yl, coumarin, dansyl chloride, rhodamine, amino-methyl coumarin, Eosin, Erythrosin, BODIPY®, Cascade Blue®, Oregon Green®, pyrene, lissamine, xanthene, acridine, oxazines, phycoerythrin, Cy3, Cy3.5, Cy5, Cy5.5, and Cy7enzymes, alkaline phosphatase, soybean peroxidase, or horseradish peroxidase may serve as a few illustrative examples.

[080] It is recalled that the substance used in the present embodiments of the method of the invention, including any molecule with a linking moiety included therein, is deposited on the plurality of surface areas where photocatalytic matter has been deposited. Accordingly, the photocatalytic matter is in many embodiments capable of catalysing a reaction that results in the removal of the respective substance (cf. above). In such embodiments the present method of the invention may include a recycling step, during which the respective substance, including any potential target matter that may be bound thereto, is removed from the surface. In these embodiments the method may include exposing the entire surface to electromagnetic radiation as explained above. As a result the photocatalytic matter catalyses the oxidation of the respective substance that is in contact therewith. Thereby the substance is being removed from the plurality of surface areas. The hydrophobic matter on the remaining surface of the substrate is again at least essentially preserved.

[081] Where desired, for instance in order to avoid the inherent hydrophobicity change (see above for TiO_x) or the decomposition of a certain photocatalyst, the photocatalytic matter may be removed. This may for instance be achieved by means of etching. Etching may for example be performed using a Brønstedt base, such as metal hydroxide, or a Brønsted acid. As an illustrative example, where the photocatalytic matter is titanium oxide, a nitric acid/hydrofluoric acid mixture, hydrochloric acid or concentrated sulfuric acid may be used to remove the same. Examples of suitable metal hydroxides include, but are not limited to sodium hydroxide, NaOH, potassium hydroxide, KOH, lithium hydroxide, LiOH, and calcium hydroxide, CaOH. By removing the photocatalytic matter, e.g. by etching, the surface of the substrate in the plurality of surface areas is uncovered and hydrophobic matter on the remaining surface is at least essentially preserved. As an illustrative example, the photocatalytic matter may be more hydrophilic than the oxidisable matter, which may for instance be hydrophobic. In such embodiments an accurate removable of the photocatalytic matter by means of etching can for instance be achieved by dipping the surface of the substrate in an etching solution and removing it within in a couple of seconds. Thereafter the substrate may be left in air or in immiscible and inert liquid. An illustrative example of a respective immiscible and inert liquid is a perfluorocarbon liquid, e.g. if the solution if highly volatile. A respective procedure may be desired in order to minimize the degradation of the oxidisable matter due to extended exposure to an etching solution.

[082] Exposing the surface of the substrate by means of etching may for instance be desired where the substrate is intended to be used for electrical applications. As an example, those skilled in the art will appreciate that the methods according to the present invention allow the manufacture of switchable surface patterns. The substrate may for instance be or comprise indium-tin oxide glass. A layer of indium-tin oxide can be fabricated to serve as photocatalytic matter while being conductive, for example by way of an electron shower bombarding the respective surface as for instance described by Yumoto et al. {Thin Solid Films (1999) 345, 38-41). In other embodiments a layer of for example TiO_x may be deposited on top of indium-tin oxide. Patterning the surface of a respective substrate with areas of hydrophobic matter may be performed as described above, including subsequent etching of photocatalytic matter used. Thereby a pattern with a wettability contrast between the indium-tin oxide glass and the hydrophobic matter is obtained. Such a wettability contrast of a respective substrate surface can be switchable by means of electrowerting (see abstract of Chen, P., 232nd ACS National Meeting, San Francisco, Sept 10-14 2006, COLL- 556).

[083] According to a further method of the invention photocatalytic matter is deposited on the entire surface of the substrate (cf. also above). According to this method, oxidisable matter, as described above, is deposited on the entire surface. The oxidisable matter may be deposited by any means, as explained above, hi this method of the invention the surface of the substrate is also patterned as explained above. In this method of the invention only the plurality of accessible surface areas is exposed to electromagnetic radiation. As explained above, the photocatalytic matter catalyses the oxidation of oxidisable matter that is in contact therewith. The oxidisable matter is thereby removed from the plurality of surface areas. As described above, the photocatalytic matter on these surface areas is exposed and the oxidisable matter on the remaining surface of the substrate is at least essentially preserved. This method further includes at least essentially removing the photocatalytic matter by means of etching (see above). Thereby the plurality of surface areas of the substrate is at least essentially uncovered. The oxidisable matter on the remaining surface of the substrate is at least essentially preserved. Accordingly, in this method there is also a pattern of discriminative wettability formed.

[084] In order that the invention may be readily understood and put into practical effect, particular embodiments will now be described by way of the following non-limiting examples. EXAMPLES

Example 1: Generation of a pattern of TiO_Y and Heptadecafluoro-1,1.,2.,2- tetrahydrodecvDtriethoxysilane (FTES) on a glass surface

[085] The box in Fig. 2A illustrates the method used in the present example. Using this method, hydrophilic-hydrophobic micropatterns were generated on glass chips. A 4-inch glass wafer was diced to rectangular chips with dimensions of 38 mm x 18 mm. After cleaning with Piranha solution, V(H₂SO₄)A^(H₂O₂) = 7/3, at 110⁰C for 0.5 h, the chip was rinsed with Milli-Q H₂O and dried with N₂. Next, the glass chips were coated with TiO_x at room temperature or at 500 ⁰C using a home-made sputter via a mask with 100-2000 μm diameter through-holes (step II in Fig. 2A). This step produced patterned coatings of amorphous TiO_x or a mixture of anatase-amorphous TiO_x on the glass surface (Luca, D. J., Optoelectron. Adv. Mater. (2005) 7, 625). The power of Ti source was 200 W. The Ar and O₂ gas flows rates were 25.2 and 10.8 seem, respectively. The chamber pressure for sputtering was 2 mTorr. After removal from the sputter chamber, the TiO_x-coated glass chips were vapour-coated with FTES (Heptadecafluoro-l,l,2,2-tetrahydrodecyl)triethoxysilane (Gelest, Inc., Morrisville, PA) at 115 ⁰C for 2 h under 1 mTorr pressure to form a hydrophobic coating (step IV in Fig. 2A; Beck, M., et al., Microelectron. Eng. (2002) 61-62, 441). [086] Functioning as a photocatalyst, TiO_x can oxidise organic adsorbates under UV irradiation. The photo-cleaving of the FTES film on the TiO_x would change the surface property from hydrophobic to hydrophilic. Figure 4 shows the change in the contact angle of water on bulk FTES-coated, amorphous TiO_x-coated or mixed TiO_x-coated glass surfaces with increasing UV irradiation time (wavelength = 254 im, 120 mJ/cm², XL-1500 UV Crosslinker, Krackeler Scientific, Inc., Albany, NY). After 2 h of UV irradiation, the advancing angle changed from 119 ± 2° to 0°, suggesting complete removal of the hydrophobic FTES coating from the surface. During UV irradiation, the difference between advancing and receding angles increased dramatically before both angles approached 0°. This result was expected as the chemical non-uniformity of a surface would be greatest at the early phase of surface degradation (Brzoska, J. B., et al. Langmuir (1994) 10, 4367). Without a TiO_x coating layer, the contact angle of water on a FTES-coated glass would remain at 110±2°, regardless of the duration of UV irradiation, demonstrating the stability of the hydrophobic surface coating. [087] In order to generate hydrophilic-hydrophobic micropatterns, the FTES-coated TiO_x-patterned glass chip (mentioned above in step IV of Fig. 2A) was irradiated under UV for 2 h (step VI in Fig. 2A). This resulted in the exposure of fresh TiO_x on the hydrophilically patterned areas with minimal impact on the hydrophobically patterned areas. Example 2: Secondary coating using a silane

[088] The present example illustrates a further coating of a patterned surface generated as described in Example 1, as well as its recycling. This secondary coating corresponds to step X depicted in Fig. 2A. The additional coating of the hydrophilic surface was obtained by exposing the chip to a silane solution. The chip was exposed to 0.5 % triethoxysilylbutyraldehyde and 0.1 % acetic acid in toluene for 20 min. As a result, the bare TiO_x surface became modified with an aldehyde-terminated silane coating. The absence of contact angle changes on the hydrophobic surface suggests negligible effect of the secondary coating step on the hydrophobic surface. The secondary coating on the hydrophilic TiO_x patterns was conveniently recycled by exposing the entire chip to UV irradiation again as described above. Upon undergoing solution-phase silylation the secondary coating was generated again.

Example 3: Generation of a pattern of FTES on a glass surface

[089] The present example illustrates the removal and recycling of TiOy from a patterned surface generated as described in Example 1. This removal/recycling corresponds to step VIII depicted in Fig. 2A. A glass chip patterned with hydrophilic TiO_x was further processed to expose a bare glass surface. The TiO_x film on the chip was etched by dipping the chip in 45 % KOH. This was followed by 15 sec of incubation in air, and rinsing with H₂O. The resulting chip consisted of bare glass in the hydrophilic areas. Figure 4 A shows dark aqueous ink drops selectively adsorbed onto the hydrophilic areas (1.2 mm diameter) of the chip.

Example 4: Suitability for ELISA assays

[090] Hydrophilic-hydrophobic patterned glass chips are currently being examined for bio-microarray applications such as enzyme-linked immunosorbent assay (ELISA) and cell- based microarray. In a typical ELISA procedure, each hydrophilic spot functions as a well, where the immobilization of antibodies occurs. Between each step, the whole microarray is rinsed with a wash solution, such as in the present example 50 mM of Tris buffer with 0.05 % Tween 20. In order to retain individual control over each spot, it is essential to keep the hydrophobic areas dry to prevent cross-contamination between the hydrophilic spots. A patterned chip was dipped into a typical ELISA wash buffer (50 mM of Tris buffer with 0.05 % Tween 20) containing 10 μM Fluorescein, and removed immediately thereafter. As shown in the fluorescence microscopy image (Figure 4B), the fluorescent buffer was only noted on the hydrophilic spots with no visible wetting of the hydrophobic perfluorocarbon surface.

Example 5: Cell adsorption and growth

[091] The present example demonstrates that a chip with a patterned surface, obtained as described above, may be used to cultivate cells as well as to perform cell-based assays. The patterned surface exposing TiO_x or bare glass in the hydrophilic areas was examined for cell adsorption and growth. A chip patterned with 1.2 mm-diameter hydrophilic areas was prepared and sterilized by 25 kGy dose of γ irradiation or by autoclaving at 121 ⁰C for 20 min. The chip, placed within a sterile Petri dish, was seeded with 0.8 μl of HepG2 cells at a concentration of 2xl0⁴cells/mL) in cell culture medium (DMEM containing 1000 mg/L glucose, 10 % fetal bovine serum (FBS), 1 % penicillin/streptomycin) on the hydrophilic areas. The drops were covered with PFCL and the Petri dish placed in a cell culture incubator (37 ⁰C, 5 % CO₂). Proliferation of the HepG2 cells was monitored over 8 days (Figure 6). As shown in Figures 3B, C, E and F, cells were able to grow on the hydrophilic areas. Further modification of the hydrophilic glass areas with another silane coating following the same liquid silylation method mentioned above for TiO_x surface led to enhanced adsorption of biomolecules.

Example 6: Formation of a wettability pattern using a continuous TiO_Y layer

[092] This example illustrates a method depicted in Fig. 2C. Following this method, micropatterns are directly generated on the glass surface using a machined mask placed in between the sputter and the glass, to selectively deposit or block the formation of TiO_x layer on glass. A TiO_x layer was sputtered onto a glass chip (see above) using the customized Filtered Cathodic Vacuum Arc (FCVA) sputtering machine, manufactured by NanoFilm Technologies International Pte Ltd, under these conditions: DC Power 200W; Argon (25.2sccm); Oxygen (10.8sccm); room temperature or 500⁰C; Chamber pressure 2mTorr. The resulting patterned coatings are either of amorphous TiO_x or mixture of anatase/amorphous TiO_x, followed by vapour-coating of fluoroalkylsilane in a custom- designed vacuum oven manufactured by Diversified Vacuum Inc. (Suffolk, VA, USA). After the glass chips were sputtered with TiO_x at room temperature or 500⁰C for 1 min (step I in Fig. 2C) to form amorphous TiO_x or a mixture of anatase-amorphous TiO_x coating, FTES was vapor-coated at 115 ⁰C under vacuum to form a hydrophobic surface (step II in Fig. 2C). The FTES-coated TiO_x chips, covered with a photomask (with patterns of 100- 2000 μm, step III in Fig. 2C), were irradiated with UV for 2 h (step IV in Fig. 2C). Thereafter the chips were instantly dipped in 45 % KOH, followed by 15 sec of incubation in air (step V in Fig. 2C) to remove the exposed TiO_x patterns, resulting in patterned chips.

[093] In fabricating and using the patterned chips following Fig. 2C, several challenges had to be faced. First, a slow deterioration of the hydrophobic FTES coating at ambient atmosphere was observed, presumably due to the photocatalytic activity of the underlying TiO_x. Such deterioration of the hydrophobic surface was not observed for the coating formed on a bare glass surface. Secondly, it was difficult to recycle the patterned TiO_x substrates. To regenerate the hydrophilic spots exactly, the alignment of the chip with a photo-mask was critical. In a typical laboratory, precision alignment is not readily available; this might lead to non-uniform feature shapes due to misalignment after repeated UV irradiation. Thirdly, it was difficult to control the shape and size of the hydrophilic spots that exposed a bare glass surface. It was often observed that rapid etching of TiO_x by KOH resulted in the under- etching of the surrounding areas and the generation of hydrophilic spots of various shapes even after short etching.

[094] The listing or discussion of a previously published document in this specification should not necessarily be taken as an acknowledgement that the document is part of the state of the art or is common general knowledge.

[095] The inventions illustratively described herein may suitably be practiced in the absence of any element or elements, limitation or limitations, not specifically disclosed herein. Thus, for example, the terms "comprising", "including," containing", etc. shall be read expansively and without limitation. Additionally, the terms and expressions employed herein have been used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by exemplary embodiments and optional features, modification and variation of the inventions embodied therein herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention.

[096] The invention has been described broadly and genetically herein. Each of the narrower species and subgeneric groupings falling within the generic disclosure also form part of the invention. This includes the generic description of the invention with a proviso or negative limitation removing any subject matter from the genus, regardless of whether or not the excised material is specifically recited herein.

[097] Other embodiments are within the following claims. In addition, where features or aspects of the invention are described in terms of Markush groups, those skilled in the art will recognize that the invention is also thereby described in terms of any individual member or subgroup of members of the Markush group.

Claims

ClaimsWhat is claimed is:

1. A method of producing a pattern of discriminative wettability on the surface of a substrate, the method comprising:

• providing a substrate;

• patterning the surface of the substrate such that a plurality of accessible surface areas is defined; • depositing only on said plurality of accessible surface areas photocatalytic matter;

• depositing on the entire surface, including the plurality of accessible surface areas, oxidisable matter, wherein said oxidisable matter is

(i) of a wettability that differs from the wettability of the photocatalytic matter, and (ii) at least essentially inert to an exposure of electromagnetic radiation that is sufficient to cause the photocatalytic matter to catalyse the oxidation of said oxidisable matter;

• exposing the entire surface to electromagnetic radiation, such that said photocatalytic matter catalyses the oxidation of such oxidisable matter that is in contact therewith, thereby

(i) removing the oxidisable matter from the plurality of surface areas and thereby exposing the photocatalytic matter on these surface areas, and (ii) at least essentially preserving the oxidisable matter on the remaining surface of the substrate, thereby forming a pattern of discriminative wettability.

2. The method of claim 1 , wherein said oxidisable matter is characterised by an advancing contact angle for water that is at least 5° or 10° higher or 5° or 10° lower than the advancing contact angle for water of said photocatalytic matter.

3. The method of claims 1 or 2, wherein said photocatalytic matter is of a lower wettability for water than said oxidisable matter.

4. The method of any one of claims 1 - 3, wherein patterning the surface of the substrate such that a plurality of accessible surface areas is defined, is achieved by any one of: - covering the remaining surface of the substrate with a mask,

- depositing a photoresist on the remaining surface of the substrate, and

- positioning a plurality of stamps above said plurality of accessible surface areas.

5. The method of claim 4, comprising first covering the remaining surface of the substrate with a mask and subsequently depositing said photocatalytic matter on the surface, thereby depositing photocatalytic matter only on said plurality of accessible surface areas.

6. The method of claim 5, wherein said mask comprises a plurality of through-holes, thereby rendering said plurality of surface areas accessible.

7. The method of claim 6, wherein said mask is a photomask.

8. The method of any one of claims 1, 2, 4, 5 or 6, the method comprising:

• providing a substrate;

• depositing on the entire surface, including the plurality of accessible surface areas, hydrophobic oxidisable matter, wherein said hydrophobic oxidisable matter is

(i) of a lower wettability for water when compared to the photocatalytic matter, and (ii) at least essentially inert to an exposure of electromagnetic radiation that is sufficient to cause the photocatalytic matter to catalyse the oxidation of said hydrophobic oxidisable matter;

• exposing the entire surface to electromagnetic radiation, such that said photocatalytic matter catalyses the oxidation of such hydrophobic oxidisable matter that is in contact therewith, thereby

(i) removing the hydrophobic oxidisable matter from the plurality of surface areas and thereby exposing the photocatalytic matter on these surface areas, and (ii) at least essentially preserving the hydrophobic oxidisable matter on the remaining surface of the substrate, thereby forming a pattern of discriminative hydrophobicity, and thereby a pattern of discriminative wettability.

9. The method of claim 8, wherein said photocatalytic matter is hydrophilic.

10. The method of any one of claims 1 - 9, wherein said electromagnetic radiation is visible light or UV light.

11. The method of any one of claims 1 - 10, wherein depositing said oxidisable matter on the entire surface is achieved by vapour coating.

12. The method of any one of claims 1 - 11, wherein said photocatalytic matter forms a layer on said plurality of accessible surface areas.

13. The method of any one of claims 1 - 12, wherein each area of said plurality of surface areas is of a maximal width in the plane of the surface that is selected in the range of about 0.1 μm to about 1 cm.

14. The method of claim 13, wherein said maximal width is selected in the range of about 100 μm to about 2000 μm.

15. The method of any one of claims 1 - 14, wherein said oxidisable matter is of a wettability for water that differs from the wettability of the surface of said substrate.

16. The method of claim 15, wherein the surface of said substrate is characterised by an advancing contact angle for water that is at least 5° higher or 5° lower than the advancing contact angle for water of said oxidisable matter.

17. The method of claim 16, wherein said substrate surface is of a material selected from the group consisting of a metal, a metalloid, a metal oxide and a metalloid oxide.

18. The method of claim 17, wherein said metalloid oxide is silicon oxide.

19. The method of any one of claims 1 - 18, wherein said oxidisable matter provides said remaining surface area with a hydrophobicity that is characterised by an advancing contact angle of water of at least about 90°.

20. The method of claim 19, wherein said contact angle is at least 100 °.

21. The method of any one of claims 1 - 20, wherein said oxidisable matter forms a film on said remaining surface of the substrate.

22. The method of claim 21 , wherein said film is a monolayer.

23. The method of any one of claims 1 - 22, wherein said oxidisable matter comprises or consists of at least one of a wax, a fat, an oil, a fattic acid, a silane, a siloxane, a perfluoroalkane, a silazane, a stannane, a polymer and a composite of a polymer and inorganic particles.

24. The method of claim 23, wherein said silane is a compound of the general formula (I): R _U1SiX_4-I11 wherein m is an integer between 1 and 3, R¹ is an aliphatic, cycloaliphatic, aromatic, arylaliphatic, and arylcycloaliphatic hydrocarbyl group, wherein for m>l each R¹ moiety is independently selected, and X is an alkoxy group or Cl.

25. The method of claims 23 or 24, wherein said silane is a haloalkylsilane.

26. The method of claim 25, wherein said haloalkylsilane is a fluoroalkylsilane.

27. The method of claim 26, wherein said fluoroalkylsilane is selected from the group of general formulas consisting of formula (I)

formula (II)

and formula (III)

wherein R² to R⁶ are independently selected from the group consisting of H, F, aliphatic, cycloaliphatic, aromatic, arylaliphatic, and arylcycloaliphatic hydrocarbyl groups, wherein at least one of R to R is or comprises F, and if n =0 at least one of R to R⁴ is or comprises F,

R⁷ to R⁹ are independently selected from the group consisting of aliphatic, cycloaliphatic, aromatic, arylaliphatic, and arylcycloaliphatic hydrocarbyl groups, and n is an integer between 0 and 10.

28. The method of claim 25, wherein said haloalkylsilane is selected from the group consisting of dimethyldichlorosilane, triethoxybromopropylsilane, chloropropyl- methyldimethoxysilane, trimethoxyiodopropylsilane, triethoxyiodopropylsilane, triethoxychlorobutylsilane, trichlorochloropropylsilane, dimethylchlorochloropropyl- silane, (dichloromethyl)trimethylsilane, triethoxy(heptafluoropropyl)-silane, trimethyl-

(trichloromethyl)-silane, methyldichloroiodoundecylsilane, dimethylbis(l , 1 ,2,2-tetra- fluoroethyl)-silane, (2-chloro- 1 , 1 ,2-trifluoroethyl)trimethyl-silane, fluorooctylmethyl- dimethoxysilane, trimethoxy(tridecafiuorohexyl)-silane, dimethyl(l , 1 ,2,2,3 ,3 ,4,4-octa- fluorobutyl)(l,l,2,2-tetrafluoroethyl)-silane, bis(α,β-dibromostyryl)dimethyl-silane, bis(l,2-dibromoethenyl)dimethylsilane, diethylbis(heptafluoropropyl)-silane, (2- bromo- 1 ,2,2-trifluoroethyl)triethyl-silane, 4,4-diethyl-2,3-difluoro- 1,1,1 -triphenyl- 1 ,4- disilahex-2-ene, triethyl(l ,2,2,3 ,3 ,3 -hexafluoro- 1 -iodopropyl)-silane, trimethyl[ 1 ,2,2,2- tetrafiuoro- 1 -(trifluoromethyl) ethyl] -silane, ethynylbis(fluoromethyl)rnethyl-silane, (l,l-difluoropropyl)dimethylphenylsilane, (l,4-diiodo-2,3-diphenyl-l,3-butadiene-l,4- diyl)bis(trimethyl)-silane, triethoxy(nonacosafluorotetradecyl)-silane, (p- chlorophenyl)(iodomethyl)dimethyl-silane, triethoxy(pentafluorophenyl)-silane, dimethyl(iodomethyl)-3-trifluoromethylphenylsilane, [(chlorodimethylsilyl)- methyl](iodomethyl)dimethyl-silane, bis[dibromo(trimethylsilyl)methyl]dimethyl- silane, (2-chloro-3 ,3 ,3 -trifluoropropyl)diethoxymethyl-silane, diethoxymethyl(2,2,2- trifluoro-l-methylethyl)-silane, [(Z)-bromo[(2Z)-2-[chloro(trimethylsilyl)methylene]- cyclohexylidene]methyl]trimethyl-silane, 5-chloro- 1 , 1 -dimethyl-silacyclopent-2-ene, (heptadecafluoroocty^dimethyltθ-^chlorosily^nonylj-silane, 1,1,1 -trimethoxy-

3,5,5,5-tetramethyl-3-(nonafluorobutyl)-trisiloxane and l,l,l,5,5,5-hexamethyl-3- (3,3,3 -trichloropropyl)-3 - [(trimethylsilyl)oxy] -trisiloxane.

29. The method of any one of claims 1 - 28, wherein depositing said photocatalytic matter is achieved by means of sputtering.

30. The method of any one of claims 1 - 29, wherein said photocatalytic matter comprises a metal oxide or a metal sulphide.

31. The method of claim 30, wherein said metal oxide is at least one of a titanium oxide, a tin oxide, a lanthanum oxide, a tantalum oxide, a gadolinium oxide, a niobium oxide, and any combination thereof.

32. The method of claim 31 , wherein said titanium oxide is TiO₂.

33. The method of any one of claims 10 - 32, wherein the wavelength of said UV light is selected to be 300 nm or shorter.

34. The method of any one of claims 10 - 33, wherein the UV light is of at least 50 mJ/cm².

35. The method of claim 34, wherein the UV light is of at least 100 mJ/cm².

36. The method of any one of claims 1 - 35, wherein exposing the entire surface to electromagnetic radiation renders the photocatalytic matter hydrophilic.

37. The method of claim 36, wherein the hydrophilic property of the photocatalytic matter is characterised by an advancing contact angle of water of less than about 90°.

38. The method of claim 37, wherein said advancing contact angle is selected to be in the range of about 0° and about 25°.

39. The method of any one of claims 1 - 38, further comprising: depositing a substance only on said plurality of surface areas, where photocatalytic matter is deposited.

40. The method of claim 39, wherein said substance is deposited after said photocatalytic matter has been deposited on said plurality of surface areas and after the entire surface has been exposed to electromagnetic radiation.

41. The method of claims 39 or 40, wherein said substance differs in its wettability for water from the wettability for water of said oxidisable matter.

42. The method of claim 41 , wherein said substance comprises a hydrophilic compound.

43. The method of claim 42, wherein said hydrophilic compound is selected from the group consisting of a silicate, a silane and a stannane.

44. The method of claim 43, wherein depositing the silane only on said plurality of surface areas is achieved by exposing the entire surface to a silane solution, a stannane solution, to silane vapour or to stannane vapour.

45. The method of any one of claims 39 - 44, wherein said substance comprises a molecule with a linking moiety.

46. The method of claim 45, wherein said linking moiety is selected from the group consisting of an amino group, an aldehyde group, a thiol group, a carboxy group, an ester, an anhydride, a sulphonate, a sulphonate ester, an imido ester, a semicarbazide, a silyl halide, an epoxide, an aziridine, a phosphoramidite and a diazoalkane.

47. The method of claim 46, wherein said molecule with a linking moiety is a silane selected from the group consisting of a monomethoxysilane, a dimethoxysilane, a trirnethoxysilane, a monochlorosilane, a dichlorosilane and a trichloroysilane.

48. The method of claim 47, wherein said silane is triethoxysilylbutyraldehyde or (3- aminopropyl)dimethoxysilane.

49. The method of claim 45, wherein said linking moiety is a receptor molecule for a target molecule, wherein said linking moiety and said target molecule define a specific binding pair.

50. The method of any one of claims 45 - 48, further comprising: contacting the surface of the substrate with a receptor molecule for a target molecule, wherein (i) said receptor molecule and said target molecule define a specific binding pair and (ii) said receptor molecule is capable of forming a complex with said linking moiety, thereby immobilising said receptor molecule on said plurality of surface areas via said linking moiety.

51. The method of claim 50, wherein immobilising said receptor molecule on said plurality of surface areas is achieved by means of forming a covalent bond between said linking moiety and said receptor molecule.

52. The method of any one of claims 49 — 51, wherein the receptor molecule is selected from the group consisting of an immunoglobulin, a mutein based on a polypeptide of the lipocalin family, a glubody, a protein based on the ankyrin or crystalline scaffold, an avimer, the T7 epitope, maltose binding protein, the HSV epitope of herpes simplex virus glycoprotein D, the hemagglutinin epitope, and the myc epitope of the transcription factor c-myc, an oligonucleotide, an oligosaccharide, an oligopeptide, biotin, dinitrophenol, digoxigenin and a metal chelator.

53. The method of any one of claims 39 — 52, further comprising contacting the surface of the substrate with said target molecule, said target molecule and said receptor molecule defining a specific binding pair, such that said receptor molecule and said target molecule form a specific binding pair complex, thereby immobilising said target molecule on said plurality of surface areas,.

54. The method of any one of claims 49 — 53, wherein said target molecule is one of a protein, a nucleic acid, a polysaccharide and any combination thereof.

55. The method of any one of claims 39 — 54, further comprising exposing the entire surface to electromagnetic radiation, such that said photocatalytic matter catalyses the oxidation of said substance that is in contact therewith, thereby

(i) removing said substance from said plurality of surface areas, and

(ii) at least essentially preserving the oxidisable matter on the remaining surface of the substrate, , thereby at least essentially restoring the pattern of discriminative hydrophobicity as defined in claim 1.

56. The method of any one of claims 1 — 55, further comprising: at least essentially removing the photocatalytic matter by means of etching, thereby at least essentially uncovering the plurality of surface areas of the substrate and at least essentially preserving said oxidisable matter on the remaining surface of the substrate.

57. The method of claim 56, wherein said etching comprises an exposure of said selected region to a Brønstedt base or a Brønsted acid.

58. The method of claim 57, wherein said Brønstedt base is a metal hydroxide.

59. The method of claim 58, wherein said metal hydroxide is at least one of NaOH, KOH,

LiOH and CaOH.

60. A pattern of discriminative wettability on a surface, obtained by the method of any one of claims 1 - 59.

61. A method of producing a pattern of discriminative wettability on the surface of a substrate, the method comprising, the method comprising:

• providing a substrate;

• depositing on the entire surface of the substrate photocatalytic matter; • vapour coating the entire surface with oxidisable matter, wherein said oxidisable matter is

(i) of a wettability that differs from the wettability of the photocatalytic matter, and

(ii) at least essentially inert to an exposure of electromagnetic radiation that is sufficient to cause the photocatalytic matter to catalyse the oxidation of said oxidisable matter;

• patterning the surface of oxidisable matter on the substrate such that a plurality of accessible surface areas is defined; and

• exposing only said plurality of accessible surface areas to electromagnetic radiation, such that said photocatalytic matter catalyses the oxidation of such oxidisable matter that is in contact therewith, thereby

62. A method of producing a hydrophobic area on a surface, the method comprising: • providing a substrate;

• depositing on the entire surface of the substrate photocatalytic matter;

• depositing on the entire surface oxidisable matter, wherein said oxidisable matter is

• patterning the surface of oxidisable matter on the substrate such that a plurality of accessible surface areas is defined;

(i) removing the oxidisable matter from the plurality of surface areas and thereby exposing the photocatalytic matter on these surface areas, and

(ii) at least essentially preserving the oxidisable matter on the remaining surface of the substrate; and

• at least essentially removing the photocatalytic matter by means of etching, thereby at least essentially uncovering the plurality of surface areas of the substrate and at least essentially preserving said oxidisable matter on the remaining surface of the substrate, thereby forming a pattern of discriminative wettability.

63. The method of claims 61 or 62, wherein said oxidisable matter is hydrophobic and of a lower wettability for water when compared to said photocatalytic matter.

64. The method of any one of claims 61 - 63, wherein patterning the surface of oxidisable matter on the substrate such that a plurality of accessible surface areas is defined, is achieved by any one of covering the remaining surface of the substrate with a mask.