Precision polishing apparatus for multi-material probe and ultra-micro electrode and polishing method thereof

Abstract

The application provides a precision polishing instrument for a multi-material probe and a super micro electrode and a polishing method thereof, and belongs to the field of precision polishing instruments. The polishing problem of quartz and glass material probes and super micro electrodes is solved. The precision polishing instrument comprises a central control box, a belt, a polishing grinding disc, an electric linear sliding table, an electron microscope and an electronic display screen. A motor in the central control box is connected with the polishing grinding disc through the belt. Filter paper is fixed on the polishing grinding disc through a filter paper fixing device. The electric linear sliding table is fixed with a probe or a super micro electrode. The polishing grinding disc is located directly below the probe or the super micro electrode. A light source is installed on one side of the polishing grinding disc, and an electron microscope is installed on the other side. The electron microscope is connected with the electronic display screen. The electron microscope is used for observing the needle tip of the probe or the super micro electrode and the polishing condition, and the observed image is displayed on the high-definition electronic display screen in real time. The precision polishing of the micron probe and the precision polishing of the super micro electrode with a small RG ratio are realized.

Description

Technical Field

[0001] This invention belongs to the field of precision polishing instruments, and in particular relates to a precision polishing instrument and polishing method for multi-material probes and ultra-micro electrodes. Background Technology

[0002] Probes (or microelectrodes) play a crucial role in various fields, including electrochemical analysis, biosensors, nanoelectronics, and environmental monitoring. Precision polishing technology for electrode probes is a key technology in micro / nano fabrication, significantly contributing to ensuring the surface quality of microelectrodes, improving the accuracy of electrochemical measurements, and promoting the development of biomedical sensors. Traditional polishing methods include mechanical grinding, chemical mechanical polishing, and electrochemical polishing. These methods effectively remove surface roughness and defects, but may also introduce new surface damage or alter the geometry of the probe (or microelectrode). Therefore, developing more refined and controllable polishing techniques is essential for fabricating high-performance probes (or microelectrodes).

[0003] Precision polishing of probes (or microelectrodes) is applied in various fields. The Sutter BV-10 microelectrode polisher is a relatively mature and widely used technology on the market, but it still has some limitations in practical use: First, this device is usually only suitable for glass materials, and it is difficult to achieve effective polishing for materials with higher hardness, such as quartz; Second, it cannot polish microelectrodes with very small RG ratio requirements; In addition, the movement of the probe during polishing still depends on manual operation, making it difficult to eliminate errors introduced by human operation; Finally, the polishing condition of the probe (or microelectrode) tip can only be observed through an eyepiece during polishing, which is not only inconvenient, but also difficult to avoid eye fatigue caused by prolonged observation. Summary of the Invention

[0004] In view of this, in order to solve the polishing problem of quartz and glass probes and microelectrodes, this invention proposes a precision polishing instrument and polishing method for multi-material probes and microelectrodes.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a precision polishing instrument for multi-material probes and microelectrodes, comprising a central control box, a belt, a polishing disc, an electric linear slide, an electron microscope, and an electronic display screen. The motor in the central control box is connected to the polishing disc via a belt. Filter paper is fixed on the polishing disc by a filter paper holder. A probe or microelectrode is fixed under the electric linear slide. The polishing disc is located directly below the probe or microelectrode. A light source is installed on one side of the polishing disc, and an electron microscope is installed on the other side. The electron microscope is connected to the electronic display screen. The electron microscope is used to observe the tip of the probe or microelectrode and the polishing condition, and displays the observed image on the high-definition electronic display screen in real time.

[0006] Furthermore, an electrode clamp is installed on the side of the polishing disc, and the electrode clamp is connected to an ultramicroelectrode (carbon nanoelectrode is one type of ultramicroelectrode) and a nickel wire.

[0007] Furthermore, the central control box is equipped with a control circuit and a high impedance detector. The central control box body is equipped with a touch screen display for controlling the stepper motor of the electric linear slide. The control circuit is connected to the touch screen display, the high impedance detector and the stepper motor respectively. The high impedance detector is used to detect the impedance of the microelectrode to be ground.

[0008] Furthermore, the polishing disc includes, from top to bottom, an optical plane fixing disc, an optical plane one, a magnet adsorption upper disc, several weak magnets, a power transmission disc, an optical plane two, and a disc support column.

[0009] Furthermore, the optical plane fixing plate and the magnet adsorption plate are clamped together with bolts to secure the optical plane.

[0010] Furthermore, the upper plate and the power transmission plate are magnetically attached together by several weak magnets to achieve a soft connection, thus avoiding the impact of vibration on the polishing disc.

[0011] Furthermore, the power transmission disc is connected to a belt, which transmits kinetic energy to the power transmission disc, and then the kinetic energy is transferred to the polishing disc by magnetic attraction.

[0012] Furthermore, the second optical plane is fixed in the groove of the grinding disc support column with glue, and the thickness of the second optical plane is greater than the height of the groove.

[0013] Furthermore, the central control box includes a power switch, a grinding disc forward / reverse rotation button, a grinding disc speed display, a grinding disc speed regulator, and a grinding disc stop rotation button. The central control box body is equipped with these components. The grinding disc speed regulator is used to adjust the rotation speed of the polishing grinding disc, and the adjustable range of the polishing grinding disc speed is 0~200 r / min.

[0014] A method for polishing micron-sized probes using a precision polishing instrument applied to multi-material probes and ultramicro electrodes, specifically including the following steps:

[0015] (1) Fabrication of micron probes: Quartz capillaries are stretched into quartz micron probes using a laser drawing machine;

[0016] (2) Polishing of quartz micron probe: Wet the polishing disc with deionized water, wet the filter paper with deionized water and place it on the polishing disc, so that the filter paper is in complete contact with the polishing disc, turn on the argon gas, adjust the pressure to 0.2~0.3 MPa, insert the tail of the probe into the ventilation tube, and then place it in the groove of the probe holder;

[0017] (3) Set the electric linear slide to lower the probe until it just contacts the polishing wheel. Observe the probe tip and its image on the wheel on the electronic display screen. Then set the step distance of the probe according to the required polishing size. Under the condition that the wheel rotates stably at 30~60 r / min, the stepper motor of the electric linear slide will move the probe downward at a speed of 0~0.2 μm / s. After it moves down to the preset step distance, the remaining time is zeroed and the probe will stop moving down, and the polishing will end.

[0018] A method for polishing carbon nanoelectrodes using a precision polishing instrument for multi-material probes and ultramicroelectrodes, specifically including the following steps:

[0019] (1) Preparation of carbon nanotube electrode: quartz capillary is stretched into quartz nanotube by laser drawing machine, the air in the quartz nanotube is emptied and filled with liquefied petroleum gas, argon gas is introduced into the quartz capillary, and carbon nanotube electrode is obtained by heating with flame gun under this atmosphere.

[0020] (2) Polishing of carbon nanoelectrodes using impedance mode: First, fix the carbon nanoelectrode and nickel wire in the groove of the probe holder and connect the electrode clip. When the distance between the tip of the carbon nanoelectrode and its image is close to 5 μm, add a drop of 10 mmol L. -1 The KCl electrolyte solution is used to cover the carbon nanoelectrode and the tip of the nickel wire. Finally, under the condition that the grinding disc rotates stably at 30~60 r / min, the stepper motor of the electric linear slide moves the carbon nanoelectrode downward at a speed of 0~0.2 μm / s. The tip of the carbon nanoelectrode contacts the polishing disc and begins polishing. When the high impedance detector detects the impedance signal, it will immediately stop polishing and automatically return to its original position.

[0021] (3) Detection using carbon nanoelectrodes: at 1 mmol L -1 In an electrolyte solution of ferrocene methanol (FcMeOH) and 1 mol L⁻¹ KCl, a two-electrode system was used, with a carbon nanotube electrode as the working electrode and Ag / AgCl as the quasi-reference electrode. The cyclic voltammetric characteristics of the carbon nanotube electrode before and after polishing were tested.

[0022] According to the formula a = i / 4.64 nFDc ,in n It is the number of electrons transferred during the oxidation of FcMeOH. aIt is the radius of the carbon nanoelectrode. i It is the limiting diffusion current of the carbon nanoelectrode. F It is Faraday's constant. c It is the molar concentration of FcMeOH. D is the diffusion coefficient of FcMeOH, used to calculate the diameter of the polished carbon nanoelectrode.

[0023] Compared with the prior art, the advantages of the precision polishing instrument and polishing method for multi-material probes and ultramicroelectrodes described in this invention are:

[0024] (1) The present invention achieves precision polishing of micron probes, meets the polishing requirements of glass and quartz materials, and can prepare probes with diameters ≥10 μm.

[0025] (2) The impedance mode provided by the present invention achieves a small RG ratio (1.1~1.5), such as the precision polishing of glass-encapsulated metal microelectrodes and carbon microelectrodes, and the diameter range of microelectrodes that can be prepared is ≥5 nm.

[0026] (3) The high-precision electric linear slide equipped with the present invention can precisely control the up and down movement of the probe (or microelectrode), and the writing of the automation program realizes the automation of the polishing of the probe or microelectrode.

[0027] (4) The high-definition display provided with this invention allows the polishing process to be observed clearly in real time.

[0028] (5) The present invention combines diamond fiber abrasive paper to polish high-hardness probes, such as quartz materials.

[0029] (6) The grinding disc of the present invention uses two very flat optical planes in direct contact and is attracted together by a circular arrangement of weak magnets, which ensures that the grinding disc is relatively flat during rotation and avoids the influence of vibration on the grinding disc.

[0030] (7) The present invention uses a belt to transfer the kinetic energy of a small stepper motor to the grinding disc, thereby avoiding the interference of the vibration of the grinding disc on the polishing of the probe or the micro-electrode.

[0031] (8) The present invention achieves smooth movement of the probe by using a high-precision electric linear slide with a repeatability accuracy of less than ±1.5 μm, ensuring that the probe will not break during the movement.

[0032] (9) The impedance detection response time of the present invention is 1 ms. The system can detect and respond to the change in impedance in a very short time, reducing the delay in returning to the original state after the polishing of the microelectrode due to system delay.

[0033] (10) The present invention uses a 4K electron microscope to display on a high-definition screen, so as to clearly and intuitively observe the grinding of the needle tip in real time during the polishing process. Attached Figure Description

[0034] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0035] Figure 1 This is a three-dimensional structural schematic diagram of the electrode probe precision polishing instrument provided by the present invention;

[0036] Figure 2 This is an exploded view of the polishing disc provided by the present invention;

[0037] Figure 3 It is the electronic display interface of the precision polisher in manual mode, that is, the touch screen display interface;

[0038] Figure 4 This is a scanning electron microscope image of a polished quartz micrometer probe;

[0039] Figure 5 These are cyclic voltammetry diagrams of carbon nanoelectrodes before and after polishing.

[0040] In the diagram: 1-Electronic display screen; 2-Power switch; 3-Grinding disc forward / reverse rotation button; 4-Grinding disc speed display; 5-Grinding disc speed regulator; 6-Grinding disc stop rotation button; 7-Touchscreen display; 8-Belt; 9-Light source; 10-Stepper motor; 11-Electronic linear slide; 12-Probe holder; 13-Polishing disc; 14-Filter paper; 15-Filter paper holder; 16-Electrode clamp; 17-Electron microscope; 18-Optical plane fixing plate; 19-Optical plane one; 20-Magnet adsorption upper plate; 21-Weak magnet; 22-Power transmission plate; 23-Optical plane two; 24-Grinding disc support column. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other, and the described embodiments are only some embodiments of the present invention, not all embodiments.

[0042] See Figure 1-5This embodiment describes a precision polishing instrument for multi-material probes and microelectrodes, comprising a central control box, a belt 8, a polishing disc 13, an electric linear slide 11, an electron microscope 17, and an electronic display screen 1. The motor in the central control box is connected to the polishing disc 13 via the belt 8. Filter paper 14 is fixed to the polishing disc 13 by a filter paper holder 15. A probe or microelectrode is fixed below the electric linear slide 11. The polishing disc 13 is located directly below the probe or microelectrode. A light source 9 is installed on one side of the polishing disc 13, and the electron microscope 17 is installed on the other side. The electron microscope 17 is connected to the electronic display screen 1. The electron microscope 17 is used to observe the tip of the probe or microelectrode and the polishing condition, and displays the observed image on the high-definition electronic display screen 1 in real time.

[0043] An electrode clamp 16 is mounted on the side of the polishing disc 13, and the electrode clamp 16 is connected to the microelectrode and the nickel wire.

[0044] The central control box contains a control circuit and a high-impedance detector. A touchscreen display 7 is mounted on the central control box body, used to control the stepper motor 10 of the electric linear slide 11. The control circuit is connected to the touchscreen display 7, the high-impedance detector, and the stepper motor 10. The high-impedance detector detects the impedance of the microelectrode to be polished; polishing stops when an impedance signal is detected. The high-impedance detector is an instrument used to measure the impedance of high-impedance circuits or devices.

[0045] The probe is a nano- or micro-scale capillary structure used for material imaging.

[0046] Microelectrodes are micron-scale and smaller electrochemical devices used for high-sensitivity and high-resolution electrochemical measurements and research, including glass-encapsulated metal microelectrodes and carbon microelectrodes.

[0047] The RG ratio is the ratio of the outer diameter of the insulating layer of the microelectrode to the radius of the conductive region.

[0048] The electronic display screen 1 is used to monitor the precision polishing process of the probe or microelectrode in real time, ensuring the accuracy of the tip polishing.

[0049] The forward and reverse rotation button 3 of the grinding disc is used to adjust the forward and reverse rotation of the grinding disc.

[0050] The grinding disc speed regulator 5 is used to adjust the grinding disc speed, and the adjustable range of the grinding disc speed is 0~200 r / min.

[0051] The touchscreen display 7 provides the operator with an intuitive way to select the polishing mode (manual mode, impedance mode), control the stepper motor 10 to drive the probe (or microelectrode) to move up and down and the speed of movement by setting parameters, start and stop the polishing process, and also display the remaining polishing time and remaining distance in real time.

[0052] The belt 8 is used to transfer the kinetic energy of the small stepper motor in the central control box to the polishing disc 13 during polishing. The polishing disc 13 includes, from top to bottom, an optical plane fixing disc 18, an optical plane one 19, a magnetic adsorption upper disc 20, several weak magnets 21, a power transmission disc 22, another optical plane 18, and a disc support column 24. The optical plane fixing disc 18 and the magnetic adsorption upper disc 20 clamp the optical plane one 19 together with bolts. The magnetic adsorption upper disc 20 and the power transmission disc 22 are magnetically attracted together by several weak magnets 21 to achieve a soft connection, avoiding the impact of vibration on the polishing disc 13. The power transmission disc 22 is connected to the belt 8, and the kinetic energy is transferred to the power transmission disc 22 through the belt 8, and then transferred to the polishing disc 13 through magnetic adsorption. The second optical plane 23 is fixed in the groove of the grinding disc support column 24 with glue, and the thickness of the second optical plane 23 is greater than the height of the groove. That is, the second optical plane 23 fixed on the grinding disc support column 24 is in a convex state. This is to enable the first optical plane 19 and the second optical plane 23 to make direct contact and ensure that the polishing disc 13 is relatively flat during rotation.

[0053] The light source 9 can be adjusted to different illumination angles as needed, providing an excellent scene for real-time observation of the polishing process.

[0054] The high-precision electric linear slide 11 is a position adjustment structure for the probe or microelectrode. The stepper motor 10 controls the up and down movement of the probe or microelectrode, and the movement speed (0~2000 μm / s) is flexibly adjustable. The stepper motor 10 is controlled by a touch screen display.

[0055] The probe holder 12 is located at the bottom of the electric linear slide 11 and is used to fix the probe.

[0056] The polishing disc 13 is a circular disc-shaped tool used for polishing probes or ultra-micro electrodes. It is the core component of this invention, with a surface profile parameter of λ / 4@633 nm.

[0057] The matching filter paper 14 forms a uniform water film on the grinding disc through siphon action, and blocks the debris generated during the polishing process.

[0058] The electrode clip 16 is used to connect the microelectrode and the nickel wire in impedance mode (there are two modes in total, one manual mode and one impedance mode. The manual mode is suitable for polishing probes, and the impedance mode is suitable for polishing microelectrodes with a small RG ratio).

[0059] The electron microscope 17 is used to observe the tip of the probe or ultra-micro electrode and its polishing condition, and displays the observed images on the high-definition electronic display screen 1 in real time.

[0060] The working principle of the precision polishing instrument for multi-material probes and ultra-micro electrodes described in this invention is as follows:

[0061] The electrode probe precision polishing instrument uses wet grinding. The filter paper 14 used in conjunction with it forms a uniform water film on the polishing disc 13 through siphon effect, and blocks the debris generated during the polishing process.

[0062] The polishing disc 13 consists of two very flat optical planes in direct contact, which are held together by a circular arrangement of weak magnets to reduce vibration and ensure that the polishing disc 13 remains relatively flat during rotation.

[0063] The polishing disc 13 is equipped with diamond fiber abrasive paper on its surface. Driven by an adjustable speed (0~200 r / min) stepper motor, the polishing disc 13 can rotate evenly and stably, thereby polishing the probe or microelectrode tip into a plane and achieving precision polishing of the probe or microelectrode tip.

[0064] During polishing, the kinetic energy of a small stepper motor is transferred to the polishing disc 13 via belt 8. A stepper motor 10 with a repeatability accuracy of less than ±1.5 μm ensures smooth movement of the probe or microelectrode, preventing damage during movement. Polishing grinds the tip of the probe or microelectrode into a flat surface, achieving precision polishing of the probe or microelectrode tip.

[0065] In addition, in impedance mode, precision polishing of the microelectrode is achieved by monitoring the impedance change between the microelectrode and the nickel wire, at 10 mmol L... -1 In a potassium chloride (KCl) electrolyte solution, when a closed circuit is formed between the polished microelectrode and the nickel wire (the microelectrode is conductive), the expected polishing state is reached. At this point, the system can be stopped in time and the original microelectrode can be returned to prevent over-polishing.

[0066] The system can fabricate probes with diameters ≥10 μm. It also integrates an impedance mode to monitor the tip state during microelectrode polishing, allowing for timely stopping and reversion of the polishing process. Microelectrodes with diameters ≥5 nm can be fabricated. To improve operational convenience and observation clarity, the system is equipped with an electron microscope 17 and an electron display 1, enabling real-time monitoring of the polishing process and ensuring the precision of tip polishing. Furthermore, the system features an adjustable light source 9, allowing for adjustments to different illumination angles as needed, providing an excellent environment for real-time observation of the polishing process.

[0067] The present invention mainly solves the following four problems: (1) it cannot polish probes with high hardness, such as quartz material; (2) it lacks impedance mode and cannot polish microelectrodes with small RG ratio; (3) the movement of probes or microelectrodes depends on manual operation and cannot avoid human error; (4) it lacks display and can only be observed through eyepiece.

[0068] The key points and areas to be protected in this invention are:

[0069] (1) The grinding disc surface used for polishing electrode probes is made of two very flat optical planes in direct contact and are attracted together by a circular arrangement of weak magnets, which ensures the relative flatness of the grinding disc during rotation and avoids the influence of vibration on the grinding disc.

[0070] (2) Automated program: The high-precision electric linear slide allows the probe to move automatically and smoothly without breaking it during the movement. It can also stop working automatically after polishing is completed.

[0071] (3) Impedance mode for polishing of microelectrodes. The impedance detection response time is 1 ms. The system can detect and respond to the change in impedance in a very short time, reducing the delay in returning to the original state after the polishing of microelectrodes due to system delay.

[0072] Example 1:

[0073] A precision polishing method for a quartz probe, specifically including the following steps:

[0074] (1) Fabrication of micrometer probes: Quartz capillaries (inner / outer diameter: 0.7 / 1.0 mm) were stretched into quartz micrometer probes using a P-2000 laser drawing machine. Typical drawing parameters included: HEAT 702, FIL 4, VEL 30, DEL134, PUL 90. This process ultimately produced probes with an opening diameter of 5 μm.

[0075] (2) Polishing of the quartz micrometer probe (manual mode): Wet the polishing disc 13 with deionized water, fold the filter paper 14 to a suitable size (fold a 7cm diameter circular filter paper three times, the final size is approximately 2cm*7cm), wet it with deionized water and place it on the polishing disc 13. The filter paper 14 needs to be in complete contact with the polishing disc 13. The function of the filter paper 14 is to remove the debris generated by the polishing of the probe tip, and to form a water film on the surface of the polishing disc 13 to prevent the liquid level from being too high and affecting the observation and polishing effect. A uniform water film with a thickness of about 3~5 μm can be formed on the surface of the polishing disc 13 by rotating the polishing disc 13 under the action of the filter paper 14. Turn on the argon gas (the probe tail is connected to the argon gas venting tube), and adjust the pressure to 0.2~0.3 MPa. The purpose of purging the argon gas is to avoid debris from clogging the probe tip due to the siphon effect. Insert the probe tail into the venting tube and then place it in the groove of the probe holder 12.

[0076] (3) Setting the stepping distance of the stepper motor 10: Click the down button "﹀" on the touch screen display 7 to start the stepper motor 10 moving downwards. At this time, the stepping distance can be set to a larger value, such as 1000 μm, until the probe tip and its image on the polishing disc 13 can be observed on the electronic display screen 1. At this time, the stepping distance needs to be reduced to prevent the probe from directly contacting the polishing disc 13 and breaking the tip. At the same time, the microscope magnification needs to be continuously increased, and the probe tip and its image on the polishing disc 13 need to be kept on the electronic display screen 1. Adjust the magnification to 5x, which is the maximum magnification of the electron microscope 17. Click the electron microscope toolbar, select "05" in the calibration column, which corresponds to the scale under the 5x lens, and select "μm" as the unit. Mark the 20 μm position on the scale, measure the distance between this position and the probe tip, and then divide by a coefficient of 0.7 (this coefficient is determined by the tilt angle of the microscope to the plane). This is the step distance to be set. With the polishing disc 13 rotating stably (30~60 r / min), the stepper motor 10 slowly moves the probe downwards (0~0.2 μm / s). Click the "CW" button to start the polishing disc 13 rotating, and then click the start button "▶" to begin polishing. Once the remaining time reaches zero, the probe will stop moving downwards, and polishing will end.

[0077] Example 2:

[0078] A polishing method for precision carbon nanotube electrodes specifically includes the following steps:

[0079] Fabrication of carbon nanotube electrodes (CNEs): Quartz capillaries (inner / outer diameter: 0.7 / 1.0 mm) were stretched into quartz nanotubes using a P-2000 laser drawing machine. Typical drawing parameters included HEAT 702, FIL 4, VEL 33, DEL126, and PUL 85, yielding quartz nanotubes with diameters of 100–200 nm. The air in the quartz nanotubes was purged and the tubes were filled with liquefied petroleum gas (0.28 MPa). Argon gas (flow rate of 100 mL / min) was introduced into the quartz capillaries (inner / outer diameter: 1.5 / 2.2 mm), and the CNEs were obtained by heating with a flame gun (950 °C) for 20 s under this atmosphere.

[0080] CNE Polishing (Impedance Mode): First, fix the CNE and nickel wire in the groove of the probe holder 12 and connect the electrode clip 16. Then adjust the magnification of the electron microscope 17 and set the step distance. Click the down button "﹀" to start the stepper motor 10 to move downwards until the CNE tip and its image on the polishing disc 13 can be observed under the electron microscope 17. When the distance between the CNE tip and its image is close to 5 μm, add a drop of 10 mmol L. -1 The KCl electrolyte solution is used to cover the CNE and the tip of the nickel wire. Finally, under the condition that the polishing disc 13 rotates stably (30~60 r / min), the stepper motor 10 slowly moves the CNE downward (0~0.2 μm / s), and the tip of the CNE contacts the polishing disc 13 to start polishing. Polishing stops when the high impedance detector detects an impedance signal.

[0081] Detection of CNE: at 1 mmol / L -1 FcMeOH and 1 mol L -1 In a KCl electrolyte solution, a two-electrode system was used, with CNE as the working electrode and Ag / AgCl as the quasi-reference electrode. The cyclic voltammetric characteristics of CNE before and after polishing were tested. According to the formula... a = i / 4.64 nFDc ,in n It is the number of electrons transferred during the oxidation of FcMeOH ( n =1), a It is the radius of CNE. i It is the limiting diffusion current of CNE. F It is Faraday's constant ( F =96485 C / mol), c It is the molar concentration of FcMeOH. c =1×10 –3 mol L -1 ), D It is the diffusion coefficient of FcMeOH (D =7.6×10 -6 cm 2 The diameter of the polished CNE was calculated to be 694 nm ( / s).

[0082] The key points of using this invention are:

[0083] (1) The present invention uses a P-2000 laser drawing machine to draw quartz or glass capillary tubes (inner diameter / outer diameter: 0.7 / 1.0mm) into quartz or glass probes.

[0084] (2) The present invention uses a matching filter paper 14 to form a water film on the polishing disc 13 through siphon effect, and blocks the debris generated during the polishing process.

[0085] (3) In this invention, the tail of the probe is inserted into a gas tube filled with argon gas to avoid debris from clogging the tip of the probe due to the siphon effect. Note: The argon gas pressure should be 0.2~0.3 MPa.

[0086] (4) The present invention controls the probe to move downward by a high-precision electric linear slide 11 until the probe tip and its image on the polishing disc 13 are observed under an electron microscope 17.

[0087] (5) In this invention, the corresponding scale is selected in the control interface of the control system, the position of the target size is marked, the distance between the position and the probe tip is measured, and the distance is divided by a coefficient of 0.7 (which is determined by the tilt angle between the microscope and the plane). This calculation result is the stepping distance of the stepper motor 10.

[0088] (6) In this invention, while the polishing disc 13 is rotating stably, the stepper motor 10 slowly moves the probe downward until the polishing is finished.

[0089] The embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A precision polishing instrument for multi-material probes and ultra-micro electrodes, characterized in that: The system includes a central control box, a belt (8), a polishing disc (13), an electric linear slide (11), an electronic eyepiece microscope (17), and an electronic display screen (1). The motor in the central control box is connected to the polishing disc (13) via the belt (8). Filter paper (14) is fixed on the polishing disc (13) by a filter paper holder 15. A probe or microelectrode is fixed under the electric linear slide (11). The polishing disc (13) is located directly below the probe or microelectrode. A light source (9) is installed on one side of the polishing disc (13), and an electronic eyepiece microscope (17) is installed on the other side. The electronic eyepiece microscope (17) is connected to the electronic display screen (1). The electronic eyepiece microscope (17) is used to observe the tip of the probe or microelectrode and the polishing condition, and displays the observed image on the high-definition electronic display screen (1) in real time. The polishing disc (13) includes, from top to bottom, an optical plane fixing disc (18), an optical plane one (19), a magnet adsorption upper disc (20), several weak magnets (21), a power transmission disc (22), an optical plane two (23), and a disc support column (24). The optical plane fixing plate (18) and the magnetic adsorption plate (20) are clamped together with the optical plane one (19) by bolts, and the optical plane two (23) is fixed in the groove of the grinding disc support column (24) by glue, and the thickness of the optical plane two (23) is greater than the height of the groove. The upper plate (20) and the power transmission plate (22) are magnetically attracted together by several weak magnets (21) to achieve a soft connection, thus avoiding the impact of vibration on the polishing disc (13).

2. The precision polishing instrument for multi-material probes and ultra-micro electrodes according to claim 1, characterized in that: An electrode clamp (16) is mounted on the side of the polishing disc (13), and the electrode clamp (16) is connected to the microelectrode and the nickel wire.

3. The precision polishing instrument for multi-material probes and ultra-micro electrodes according to claim 2, characterized in that: The central control box is equipped with a control circuit and a high impedance detector. The central control box body is equipped with a touch screen display (7) for controlling the stepper motor (10) of the electric linear slide (11) to lift up and down. The control circuit is connected to the touch screen display (7), the high impedance detector and the stepper motor (10) respectively. The high impedance detector is used to detect the impedance of the microelectrode to be ground.

4. The precision polishing instrument for multi-material probes and ultra-micro electrodes according to claim 3, characterized in that: The power transmission disk (22) is connected to the belt (8), and the kinetic energy is transmitted to the power transmission disk (22) through the belt (8), and then the kinetic energy is transmitted to the polishing disk (13) through magnetic attraction.

5. The precision polishing instrument for multi-material probes and ultra-micro electrodes according to claim 1, characterized in that: The central control box includes a power switch (2), a grinding disc forward and reverse rotation button (3), a grinding disc speed display (4), a grinding disc speed regulator (5), and a grinding disc stop rotation button (6). The central control box body is equipped with a power switch (2), a grinding disc forward and reverse rotation button (3), a grinding disc speed display (4), a grinding disc speed regulator (5), and a grinding disc stop rotation button (6). The grinding disc speed regulator (5) is used to adjust the speed of the polishing grinding disc (13). The adjustable range of the polishing grinding disc (13) speed is 0~200 r / min.

6. A method for polishing a micrometer probe using a precision polishing instrument for multi-material probes and ultra-micro electrodes as described in any one of claims 1-5, characterized in that: Specifically, the following steps are included: (1) Fabrication of micron probes: Quartz capillaries are stretched into quartz micron probes using a laser drawing machine; (2) Polishing of quartz micro probe: Wet the polishing disc (13) with deionized water, wet the filter paper (14) with deionized water and place it on the polishing disc (13), so that the filter paper (14) is in complete contact with the polishing disc (13), turn on the argon gas, adjust the pressure to 0.2~0.3 MPa, insert the tail of the probe into the ventilation tube, and then place it in the groove of the probe holder (12); (3) Set the electric linear slide (11) to lower the probe to just contact the polishing disk. Observe the probe tip and its image on the polishing disk (13) on the electronic display screen (1). Under the condition that the disk rotates stably at 30~60 r / min, the stepper motor (10) of the electric linear slide (11) moves the probe downward at a speed of 0~0.2 μm / s. When it moves down to the preset step distance, the remaining time is zeroed, the probe will stop moving down, and the polishing will end.

7. A method for polishing carbon nanoelectrodes using a precision polishing instrument for multi-material probes and ultramicroelectrodes as described in any one of claims 1-5, characterized in that: Specifically, the following steps are included: (1) Preparation of carbon nanotube electrode: quartz capillary is stretched into quartz nanotube by laser drawing machine, the air in the quartz nanotube is emptied and filled with liquefied petroleum gas, argon gas is introduced into the quartz capillary, and carbon nanotube electrode is obtained by heating with flame gun under this atmosphere. (2) Polishing of carbon nanoelectrodes using impedance mode: First, fix the carbon nanoelectrode and nickel wire in the groove of the probe holder (12) and connect the electrode clip (16). When the distance between the tip of the carbon nanoelectrode and its image is close to 5 μm, add a drop of 10 mmol L. -1 KCl electrolyte solution is used to cover carbon nanoelectrodes and nickel wire tips; finally, under the condition that the grinding disc rotates stably at 30~60 r / min, the stepper motor of the electric linear slide (11) moves the carbon nanoelectrodes downward at a speed of 0~0.2 μm / s, and the carbon nanoelectrode tips contact the polishing grinding disc (13) to start polishing. When the high impedance detector detects the impedance signal, it will stop polishing in time and automatically return to the original position. (3) Detection using carbon nanoelectrodes: at 1 mmol L -1 FcMeOH and 1 mol L -1 In a KCl electrolyte solution, a two-electrode system was used, with a carbon nanotube electrode as the working electrode and Ag / AgCl as the quasi-reference electrode. The cyclic voltammetric characteristics of the carbon nanotube electrode before and after polishing were tested. According to the formula a = i / 4.64 nFDc ,in n It is the number of electrons transferred during the oxidation of FcMeOH. a It is the radius of the carbon nanoelectrode. i It is the limiting diffusion current of the carbon nanoelectrode. F It is Faraday's constant. c It is the molar concentration of FcMeOH. D is the diffusion coefficient of FcMeOH, used to calculate the diameter of the polished carbon nanoelectrode.

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