CN1110786A

CN1110786A - Ultramicro nm electrode and ultramicro sensor

Info

Publication number: CN1110786A
Application number: CN 94104755
Authority: CN
Inventors: 张学记; 周性尧; 张悟铭
Original assignee: Wuhan University WHU
Current assignee: Wuhan University WHU
Priority date: 1994-04-29
Filing date: 1994-04-29
Publication date: 1995-10-25
Anticipated expiration: 2014-04-29
Also published as: CN1040043C

Abstract

Ion beam etching technique is used to make up electrode with minimal size of 30 nm. The electrode features controllable size, molecule-class surface smoothness and high mechanical strength, so it may be used for measuring in single cell. A voltol insulating method is disclosed to make up nm-class disk electrode with excellent electrochemical performance. The electrode and its supporter are sealed in vacuum to avoid pollution. The nm-class ultramicro pH sensor is made up by chemical trimming of said electrode.

Description

Ultramicro nm electrode and ultramicro sensor

The invention discloses the manufacture method of a kind of nanoscale ultramicroelectrode and ultra micro sensor.Affiliated technical field is analytical chemistry, Electroanalytical Chemistry, electrochemical sensor.

The progress of nanometer ultramicroelectrode is unhappy, and its main cause is that the manufacturing technology difficulty of nanometer ultramicroelectrode is big, even make the nanometer ultramicroelectrode, also because of various reasons, major part can not be practical.People such as White [H.S.White et.al.; J.Phys.Chem.1987 91.3559] reported the electroded preparation method of nanoscale platinum; we [Zhang Xueji, open realize inscription, Zhou Xingyao, Wang Zhu " SCI " 1993,14(7) 927] carried out detailed preparation, characterization research to nanoscale gold ribbon electrode.People such as Penner [R.N.Penner et.al., Sci.1990,250,1180] have proposed to prepare the nanometer platinum disk electrode with the method that heating draws.Above-mentioned work is for certain basis has been laid in the theoretical research of nano-electrode.But though above-mentioned electrode is called nano-electrode, the size of entire electrode is bigger, and electrode is to be embedded in the big supporter, can not be used for micro-zone analysis, makes the application of electrode be subjected to great restriction.In addition, some manufacture craft (as the heating drawing) is difficult to guarantee the repeatability of electrode.Recently, people such as Ewing [A.G.Ewing et.al., Anal.Chem.1992.64.1368] etching carbon fiber in flame has made carbon nano-fiber electrode (about tip diameter 400nm), for nano-electrode has promoted a step forward in the application of microcell.But the success ratio that gets electrode with this legal system is low, can not make identical electrode.Coarse with the electrode surface that this method obtains, intensity difference both had been not suitable for doing theoretical research, also was difficult to practical application.Particularly be used for aspect the intracellular species analysis, kind electrode is just more powerless.

The objective of the invention is: adopt the ion beam etching law technology, preparation size is controlled, smooth surface, physical strength height, nanoscale ultra micro carbon fiber electrode that chemical property is good and other metal ultramicroelectrode; Proposition is cut the method for exposing the plane with eletrode tip again and is made the nanoscale disc electrode at the nanoscale post electrode surface electropolymerization 3-allyl catechol nanoscale insulation course that makes.Made the pH sensor at nanoscale electrode face finish polyaniline first.

Be the technical measures that realize that the object of the invention is taked:

1. the tip of ion beam bombardment carbon fiber makes nano level eletrode tip.During bombardment, experiment parameter: accelerating potential V _a=2000-8000kV, ion beam current I=0.1-20mA, changes target speed omega=5-85rpm, bombardment time t=2-20hr, vacuum tightness τ=0.05-0.0001Pa by glancing angle θ=10-35 °.

2. carbon fiber adopts sliver-powder conducting glue to be connected with the coaxial shielding line, connects the back and places 0.5-2hr down at 60-80 ℃.

3. adopt and under vacuum, heat,, avoided the pollution of electrode surface supporter glass capillary and carbon fiber or metal electrode involution.

4. adopt the method for electropolymerization 3-allyl catechol to carry out insulating.Experiment condition: electrolytic solution consists of: 0.05-0.2ml/L3-allyl catechol.1.0 * 10 ^-4-1.0 * 10 ^-6Mol/L phenol and 0.1-0.5mol/L butanols are dissolved in the methanol aqueous solution of 20-80%, use NH ₃H ₂O regulates pH to 8.5-10.0 scope.Polymerization current potential: 3.0-4.0V, polymerization time 5-15min, crosslinking temperature 120-250 ℃, crosslinking time 10-30min.

With the nano-electrode that the present invention makes, following advantage is arranged: 1. the electrode size that makes is controlled, and the minimum effectively tip that can make can reach 30nm.2. owing to adopt the ion beam bombardment technology, the atom of carbon fiber surface " is beaten " one by one, so the surface of carbon fiber has the smooth smoothness of molecular level, carbon fiber is needle-like backward by the tip and evenly increases slightly, and the electrode surface that makes cleans very much, the intensity height.So electrode has good electrochemical, can easily insert in the individual cells again and measure.Enter cell, both required the intensity height of electrode, require the smooth surface of electrode again, like this, sealing-in easily between cell membrane and electrode.3. success ratio height.Because be to adopt ion beam etching, various parameters all can strict be controlled, and have got rid of the artificial factors such as " skills " in the flame etching method.4. electrode favorable reproducibility.As long as the controlled variable unanimity will obtain the identical electrode of parameter.5. can produce in batches.Stepped a step of key for the commercialization of nano-electrode and nano-sensor.

The electrode that makes successfully inserts the only single neurocyte of 10 μ m of diameter first, and dynamically analyzes.On March 31st, 94, State Education Commission identified this project, thought to be in the first place in the world by beam-plasma lithographic technique and the prepared carbon nano-fiber ultramicroelectrode that the making of carbon fiber ultramicroelectrode is adopted first.This electrode successfully inserts in the single neurocyte again and tests, and this is an important breakthrough.Therefore, this achievement is in international most advanced level.

Description of drawings: Fig. 1 is the synoptic diagram of electrode.1 is carbon fiber among Fig. 1; 2 is insulation course; 3 is eletrode tip; 4 is carbon fiber and the most advanced and sophisticated faying face capillaceous of glass in the electrode; 5 is the contact of carbon fiber and lead; 6 is glass capillary, and 7 is lead, and 8 is epoxy resin.Fig. 2 makes the electromicroscopic photograph of electrode for the present invention.Fig. 3 is the electromicroscopic photograph of the electrode that makes with flame method.

Embodiment: the carbon fiber of the diameter 7 μ m that handle well with cleaning surfaces.With sliver-powder conducting glue it is connected with lead.Under 70 ℃, place 1hr, it is penetrated one at microscopically draw the carbon fiber that good kapillary (tip diameter is 10 μ m altogether) exposes about 10-100 μ m.Lead and kapillary behind fixed with epoxy resin, under vacuum capillary tip added heat-sealing and melts, and in ion beam current the carbon fiber tip is etched into nanoscale, concrete V parameter _a=4000kV, I=5mA, 0=15 ℃, ω=10rpm, t=10h, τ=0.0005Pa obtain the nano-pillar electrode.

At polymerization current potential V=3.5V, polymerization time t=10min, electrolytic solution form: 0.1mol/L3-allyl benzene diphenol, 100 * 10 with above-mentioned electrode ^-5Mol/L, phenol and 0.15mol/L butanols, solvent is 1: 1 methanol aqueous solution, transfer to pH=9.2 with ammoniacal liquor, obtain the nanoscale polymeric membrane, with this electrode secondary water, ethanol is supersound washing 5min respectively, crosslinked 20min under 140 ℃ cuts any with eletrode tip then and exposes the nanometer plate electrode in micromanipulation system.

Claims

1, a kind of method for making that adopts ibl fabrication techniques nanoscale ultramicroelectrode and decorated nanometer electrode surface to be made into ultra micro sensor, it is characterized in that: with the tip of little carbon fiber of ion beam bombardment nanoscale and metal ultramicroelectrode, make nano level eletrode tip, and at the nanoscale post electrode surface electropolymerization that makes the nano level insulation course of one deck 3-allyl catechol, again the eletrode tip incision is manifested the plane, and become nanoscale dish telegram, and nanoscale electrode face finish polyaniline is made the pH sensor; At last the nanoscale electrode of making is combined with telegram supporter, electrode material under straight sky; The minimum diameter of made electrode can reach 30nm.

2, by the described nanoscale electrode of claim 1, it is characterized in that: ion beam bombardment carbon fiber or metal tip, the parameter of selected ion beam is: accelerating potential V _a≤ 2000 to 8000KV, and ion beam current 〉=0.1 is to 20mA, and target speed omega 〉=5 are changeed to 85rpm to 35 ℃ in glancing angle θ 〉=10, and bombardment time t 〉=2 are to 20hr, and vacuum tightness τ 〉=0.0001 is to 0.005Pa;

3, by the described nanoscale electrode surface of claim 1 insulation course, it is characterized in that: the electrolytic solution of electropolymerization consists of 3-allyl catechol: 〉=0.05 to 0.2 mol, phenol 〉=1.0 * 10 ^-6To 1.0 * 10 ^-4Mol, butanols 〉=0.1 be to 0.5 mol, they are dissolved in 〉=20 to 80% methanol aqueous solution in, use NH ₃H ₂O regulates pH value to 〉=8.5 to 10.0 scopes; Polymerization current potential: 〉=3.0 to 4.0V; Polymerization time: 〉=5 to 15min; Crosslinking temperature: 〉=120 to 250 ℃; Crosslinking time: 〉=10 to 30min;

4, by claim 1,2 described nanoscale electrodes is characterized in that: adopt and heat under vacuum, supporter glass capillary and carbon fiber or metal electrode material involution.