Near-atomic scale electrochemical machining product co-removal methods, systems, and applications

Abstract

This invention discloses a method for the coordinated removal of products from near-atomic-scale electrochemical machining, along with its system apparatus and applications. The core of this method lies in the synergistic use of chemical complexation, pulsed electric field modulation, and interfacial electrostatic repulsion to proactively address the problem of product blockage within near-atomic-scale machining channels. Specifically, by adding a strong complexing agent to the electrolyte, the metal ions generated during machining are converted in situ into soluble complexed anions. A composite waveform, including an anodic pulse during machining, a zero-potential intermittent period during diffusion, and a reverse cathode pulse during impurity removal, provides dual impurity removal momentum through diffusion and electromigration. Simultaneously, the inner wall of the ion channel protein is negatively modified to reduce product transport resistance and adsorption through electrostatic repulsion. The synergistic effect of these three mechanisms enables effective and continuous product management without compromising machining locality. Correspondingly, this invention also provides a dedicated machining system for implementing this method and its application in the machining of easily passivated metal materials.

Description

Technical Field

[0001] This invention belongs to the interdisciplinary field of precision micro-nano manufacturing technology, electrochemical processing and nanotechnology, and specifically relates to a method for the coordinated removal of products from near-atomic scale electrochemical processing, as well as its system device and application. Background Technology

[0002] As device feature sizes continue to shrink towards the nanometer and atomic scales, the development of corresponding ultra-precision machining technologies has become an urgent need in cutting-edge manufacturing fields. Electrochemical machining technology, due to its advantages such as no heat-affected zone and no tool wear, has shown potential in the fabrication of micro and nanostructures. However, when the machining scale shrinks to the near-atomic level, a long-neglected but crucial problem becomes apparent: the effective removal of reaction products. In existing micro-nano electrochemical machining technologies such as mask electrolysis and micro-electrochemical wire cutting, for example, the schemes disclosed in Chinese patents CN114985853B and CN115592218B, product removal mainly relies on forced convection or scouring in the micrometer-level machining gap. This macroscopic flow method completely fails at the submicrometer, especially nanometer, scale because strong liquid flow disrupts the localization of the machining process, and the viscous resistance is extremely high in the extremely confined space, making it almost impossible to establish effective convection. Products can only be removed by slow diffusion, which easily accumulates in the machining area, leading to a decrease in machining accuracy or even complete termination due to hydroxide precipitation.

[0003] For more sophisticated techniques such as scanning electrochemical microscopy, mass transfer primarily relies on diffusion. While this avoids flow interference, the inherent randomness and slowness of the diffusion process not only limit processing speed but also lead to blurred reaction zone boundaries, making it difficult to achieve clear nanoscale profiles. Furthermore, for easily passivated metals such as nickel and titanium, the metal cations generated during dissolution readily form dense hydroxide passivation films near the processing point. Traditional solutions involve using high-concentration, highly corrosive electrolytes or high-flow-rate rinsing, as disclosed in Chinese patents CN105364236B and CN107470727B. However, this fundamentally contradicts the localization and environmental friendliness required for high-precision machining.

[0004] The applicant initially proposed using a biomimetic confined ECM method to fundamentally solve the localization problem. The biomimetic approach involves using fixed-size biological nanopores (such as α-hemolysin pores) as electrolyte channels, embedding them into a supporting phospholipid bilayer to construct a "confined electrolyte" environment, theoretically achieving atomic-level processing resolution. However, this technical approach pushes the product removal problem of micro / nano ECM to its extreme: within the extremely confined space with pore sizes close to the atomic scale, convection completely fails, and mass transfer relies solely on diffusion and electromigration. The high concentration of metal ions generated during processing cannot disperse quickly, and their concentration at the channel outlet instantly reaches saturation, rapidly forming hydroxide precipitates that clog the channels. Existing methods in micro / nano ECMs to promote removal, such as forced convection and high-speed flushing, are completely ineffective here, and simple pulse parameter adjustments cannot address the chemical-thermodynamic nature of precipitation formation. Therefore, the problem of product blockage within ion channels has become the most critical bottleneck restricting the development of atomic-scale ECM technology. Summary of the Invention

[0005] Technical Problem Solved: Addressing the challenge in existing near-atomic scale electrochemical machining technologies where reaction products easily aggregate and precipitate within nanoscale machining channels, leading to channel blockage and consequently, process interruptions or precision degradation, this paper provides a method for the coordinated removal of products from near-atomic scale electrochemical machining, along with its system apparatus and applications. This method aims to suppress precipitation formation at its source by synergistically integrating chemical transformation, electrical driving, and interface regulation, providing multiple active driving forces for product removal, thereby ensuring stable and controllable near-atomic scale electrochemical dissolution machining.

[0006] Technical Solution: A method for the coordinated removal of products from near-atomic-scale electrochemical machining, comprising the following steps: providing a workpiece anode and constructing a phospholipid bilayer insulating mask on its surface; placing the workpiece anode with the phospholipid bilayer on its surface in an electrolyte, wherein the electrolyte contains a strong complexing agent at a concentration of 1 mM to saturation and an ion channel protein, wherein the strong complexing agent is ethylenediaminetetraacetic acid or citrate, and the inner wall of the ion channel protein is negatively charged; applying a composite pulse voltage waveform to the working electrode using a pulsed power supply, wherein the waveform sequentially includes: a machining period anode pulse with an amplitude of 100 mV to 500 mV and a pulse width of 10 ns to 1 µs; a diffusion period zero-potential interval with a duration of 1 to 5 times the pulse width of the machining period anode pulse; and a removal period cathode reverse pulse with an amplitude of 1.5 to 3 times the amplitude of the machining period anode pulse and a pulse width of 50 ns to 1 µs.

[0007] The aforementioned strong complexing agent is ethylenediaminetetraacetic acid (EDTA), and its concentration in the electrolyte is 1 mM to 10 mM.

[0008] The aforementioned ion channel proteins are MspA protein, α-hemolysin protein, or their functional analogs, with a pore size ranging from 0.5 nm to 15 nm.

[0009] The pulse width of the anode pulse during the processing period is 100 ns, the duration of the zero potential interval during the diffusion period is 200 ns, and the amplitude of the cathode reverse pulse during the impurity removal period is -500 mV with a pulse width of 500 ns.

[0010] The aforementioned ion channel proteins are genetically engineered MspA proteins or α-hemolysin proteins, whose inner walls are negatively charged under processing conditions. They are used to form processing channels in electrolytic processing and to repel negatively charged complexed anionic products.

[0011] A near-atomic-scale electrochemical machining system (model: PARSTATVERSASCAN, USA, additional configurations are subject to change below) for implementing the method includes: an electrolytic cell unit for containing an electrolyte containing a strong complexing agent and ion channel proteins; a working electrode unit including a workpiece as an anode and a tool electrode as a cathode, wherein a phospholipid bilayer insulating mask is constructed on the anode surface of the workpiece; a pulse power supply unit (model: AWG70000B, Tektronix, USA) connected to the working electrode unit for outputting the composite pulse voltage waveform; a control system connected to the pulse power supply unit for setting and regulating the parameters of the waveform; and a current monitoring unit (model: MSO22, SMU 2600B, Tektronix, USA; DLPCA-100, FEMTO, Germany) for real-time monitoring of the current signal within the machining channel and feeding it back to the control system.

[0012] The aforementioned current monitoring unit includes a source meter with fA-level accuracy and a transimpedance gain of 10. 5 V / A-10 9 Transimpedance amplifiers and high-speed oscilloscopes.

[0013] The above method is applied to near-atomic scale processing of easily passivated metal materials, wherein the easily passivated metal material is nickel, titanium, or their alloy.

[0014] A method for near-atomic scale electrolytic machining using the system includes the following steps: providing a workpiece anode with a phospholipid bilayer on its surface; placing the workpiece anode in an electrolyte containing a strong complexing agent and ion channel proteins; setting the pulse power supply to output the composite pulse voltage waveform through a control system; starting the machining process, monitoring the current signal in real time and dynamically adjusting the pulse parameters to continuously discharge the reaction products under the synergistic effect of concentration gradient, electromigration force, and electrostatic repulsion force.

[0015] The aforementioned phospholipid bilayer is formed by self-assembly of the anode in a phosphate buffer containing dioleoylphosphatidylcholine.

[0016] Technical Principle: First, this invention alters the reaction pathway through chemical regulation. A sufficient amount of strong complexing agent is pre-added to the electrolyte. Its key role is to immediately bind with the target metal atoms during the electrochemical dissolution, transforming the metal cations, which readily combine with hydroxide ions in aqueous solution to form precipitates, into stable, soluble complex anions. This step fundamentally inhibits the formation of solid hydroxide precipitates from a chemical thermodynamic perspective, eliminating the main source of blockage and serving as a prerequisite for the effectiveness of all subsequent removal measures. Second, a time-sequential pulsed electric field provides active transport force. A composite pulse waveform containing specific processing, diffusion, and impurity removal phases is used to spatiotemporally program the mass transfer process. After localized dissolution and formation of complex anions during the processing phase, the diffusion phase begins. At this point, the electric field is zero, and the extremely high local concentration gradient formed during this phase drives the product to spontaneously diffuse into the low-concentration bulk solution. Immediately following, during the impurity removal phase, a cathode pulse of opposite polarity is applied. The electric field force induces directional electromigration of the negatively charged complex anions, actively pushing them out of the channel. This relay design, driven by concentration gradient diffusion and reverse electromigration, constitutes an active pumping cycle, solving the problem of low efficiency with passive diffusion alone. Finally, interface engineering is used to reduce transport resistance for synergistic effect. The inner wall of the ion channel protein is functionalized to give its surface a net negative charge under processing conditions. This modification generates a continuous electrostatic repulsion between the inner wall and the similarly negatively charged complexed anionic products. This repulsion plays a dual synergistic role: first, it prevents the adsorption and retention of product ions on the channel wall, avoiding local narrowing or blockage caused by adsorption accumulation; second, it is equivalent to applying an additional outward repulsive force on the transport path, consistent with the direction of the diffusion driving force and electromigration force, thereby significantly reducing the overall resistance of ion movement within the nanochannel and improving the overall efficiency of the aforementioned pumping cycle.

[0017] Beneficial Effects: This invention achieves a shift from passive response to proactive prevention and management through the coupling and mutual enhancement of three methods: chemical regulation, synergistic electrochemical parameters, and interface engineering. At the chemical regulation level, adding sufficient strong complexing agents to the electrolyte allows for in-situ binding with metal ions generated during dissolution, transforming them from cations prone to hydroxide precipitation into stable, soluble complex anions. This chemical transformation cuts off the thermodynamic path of precipitation formation at the source of the reaction, representing the most fundamental solution to the blockage problem. However, chemical transformation alone is insufficient to ensure the effective removal of products from the extremely narrow nanochannels. Therefore, this invention designs a composite pulsed voltage waveform encompassing processing, diffusion, and impurity removal phases, providing a time-sequential and proactive kinetic driving force for the removal of soluble complex anions. During the diffusion phase following processing, a zero-potential interval creates a time window for the product to diffuse outwards based on its concentration gradient; in the subsequent impurity removal phase, the applied cathode reverse pulse exerts a directional pushing force on the negatively charged complex anions towards the outside of the channel through electromigration, significantly accelerating their removal rate. This pulsed design, combining diffusion traction and electromigration, constitutes an active pumping mechanism for product expulsion. The effectiveness of chemical and pulsed regulation further benefits from the synergy of interface engineering techniques. By negatively modifying the inner wall of the ion channel protein, it generates a continuous electrostatic repulsion with the negatively charged complexed anionic product in the processing environment. This repulsion significantly reduces the adsorption probability of product ions on the channel inner wall, preventing local blockage caused by adsorption accumulation; on the other hand, it provides a lubricating effect for ion transport, reducing the resistance to its movement along the channel, allowing concentration gradient diffusion and electromigration to proceed more smoothly. Thus, chemical regulation alters the intrinsic properties of the product, creating the premise for utilizing electromigration and electrostatic repulsion; pulsed regulation provides the spatiotemporal driving force for expulsion; and interface modification optimizes the transport microenvironment, ensuring the efficiency of the expulsion process. These three are not simply superimposed, but constitute an interlocking and interdependent organic whole, and the overall technical effect produced by their synergistic effect far exceeds the level achievable by any single method. This synergistic mechanism enables long-term, stable, and reliable processing while maintaining near-atomic-scale localization, greatly promoting the practical application of this precision manufacturing technology. Furthermore, this synergistic strategy is designed based on the physicochemical nature of product transport. By adjusting the type of complexing agent, pulse parameters, and modification methods, it can be adapted to the processing of various easily passivated metal materials, demonstrating good versatility and scalability. Attached Figure Description

[0018] Figure 1 This is a schematic diagram illustrating the principle of the product co-discharge method described in this invention during the processing.

[0019] Figure 2This is a schematic diagram showing the relative positions of ion channel proteins under different excitation frequencies.

[0020] Figure 3 This is a schematic diagram showing the relative positions of ion channel proteins under the same excitation frequency but different phase angles.

[0021] Figure 4 This is a three-dimensional structural diagram of the MspA ion channel protein and a schematic diagram of the interface engineering modification sites.

[0022] Figure 5 This is a schematic diagram of the diffusion process of reaction products during the diffusion phase in a composite pulse waveform.

[0023] Figure 6 This is a schematic diagram of the process by which reaction products in the impurity removal period of a composite pulse waveform are removed under the action of reverse electromigration.

[0024] Figure 7 A high-resolution transmission electron microscope image of a nickel nanopore with a diameter of 1 nm produced by electrolytic processing.

[0025] Figure 8 This is a comparison of the gene sequences of the MspA ion channel protein after and before the mutation.

[0026] Figure 9 The images show gel electrophoresis and high-resolution electron micrographs of the MspA ion channel protein after its mutation and purification.

[0027] Figure 10 This is a high-resolution transmission electron microscope image of nickel nanopores without the use of synergistic control electrolytic processing.

[0028] Figure 11 The current-time decay curve for electrolytic processing without synergistic control is shown.

[0029] Figure 12 This is a schematic diagram of the three-dimensional structure of wild-type α-hemolysin (α-HL) protein.

[0030] Figure 13 A high-resolution TEM image of the cross-section of processed titanium metal. Detailed Implementation

[0031] The specific implementation process of the present invention will be described in detail below with reference to the accompanying drawings.

[0032] To achieve the above objectives, this invention proposes a new paradigm of synergistic regulation. Its core idea is to abandon the passive approach to blockage and instead actively intervene and optimize from three aspects—reaction source, process driving force, and transport environment—through the organic combination of chemical regulation, electroparameter synergy, and interface engineering, forming a systematic solution.

[0033] Specifically, the present invention provides the following technical solution: a method for removing products from near-atomic-scale electrochemical processing of ion channel proteins, characterized in that the method includes the following synergistically implemented steps:

[0034] Chemical regulation steps: Add sufficient strong complexing agent to the electrolyte. This complexing agent can form stable, soluble negatively charged complexed anions with the target processed metal ions, thereby avoiding the formation of insoluble hydroxide precipitates from the chemical pathway.

[0035] Electrical parameter coordination steps: Processing is performed using pulse voltages with a specific waveform, which includes an anodic pulse period for metal dissolution, an intermittent period for product diffusion driven by concentration gradient, and an optional cathode reverse pulse period for actively expelling residual products by applying electric field force. An active "pumping" effect is generated through timing control.

[0036] Interface engineering steps: The inner wall of the near-atomic scale processing channel is modified to give it a net negative charge, thereby generating electrostatic repulsion with the negatively charged complexed anionic products, reducing their transport resistance and adsorption probability within the channel; wherein, the chemical regulation step, the electrical parameter synergy step, and the interface engineering step work together to achieve efficient and continuous product discharge and ensure stable processing.

[0037] Correspondingly, the present invention also provides a system for implementing the above method. The system includes: an electrolytic cell unit for containing an electrolyte containing a specific concentration of a strong complexing agent; a working electrode unit including a workpiece as an anode and a tool electrode as a cathode, the end of the tool electrode having the near-atomic-scale processing channel integrated thereon; a pulse power supply unit connected to the working electrode unit and configured to output a composite waveform comprising a processing-phase anode pulse, a diffusion-phase zero-potential interval, and a discharge-phase cathode reverse pulse; and a control system connected to the pulse power supply unit for precisely setting and independently controlling various parameters of the composite waveform, including the amplitude and width of the anode pulse, the duration of the diffusion phase, and the amplitude, width, and application timing of the cathode reverse pulse.

[0038] Anode pretreatment steps: The anode is first degreased, washed with water, and dried, and then treated with argon-hydrogen mixed gas (volume ratio 96:4) plasma. Dioleoylphosphatidylcholine (DOPC) phospholipid monomer (concentration 10 mg / mL) is dissolved in phosphate buffer (electrolyte) at pH 7.4. The anode is immersed in the electrolyte for 5-10 minutes, and a phospholipid bilayer insulating mask is formed on the anode surface through self-assembly.

[0039] Example 1

[0040] The system of this invention mainly includes an electrolytic cell unit, a working electrode unit, a pulse power supply unit, a current monitoring unit, and a control system. The electrolytic cell unit contains a 0.5 mol / L NaCl electrolyte with a molar concentration of 1 mM EDTA strong complexing agent 7 and gene-edited MspA ion channel protein 5, wherein the inner wall amino acids 3, 4, and 6 of the MspA ion channel protein 5 are modified to negatively charged glutamate. The working electrode unit includes metallic nickel as the workpiece anode 1 and a tool electrode as the cathode, with a phospholipid bilayer insulating mask disposed on the workpiece anode 1. The pulse power supply unit is connected to the working electrode, with the negative terminal connected to the tool electrode and the positive terminal connected to the metal (nickel) anode 1. It outputs a composite waveform containing an anode pulse during the processing phase, a zero-potential interval during the diffusion phase, and a cathode reverse pulse during the impurity removal phase. The width of the anode pulse during the processing phase is set to the desired value; in this experiment, the pulse width is 100 ns, and the duration of the diffusion phase is twice the width of the anode pulse. The anode pulse amplitude is 250 mV, and the amplitude of the cathode reverse pulse during the impurity removal phase is 2.0 times the amplitude of the anode pulse during the processing phase, with a pulse width of 500 nanoseconds. The current monitoring unit is a source meter with fA-level accuracy and a transimpedance gain of 10. 5 A transimpedance amplifier and a high-speed oscilloscope (V / A) are used to acquire the current signal within the ion channel. The control system, connected to the power pulse unit and the current monitoring unit, precisely sets and independently adjusts various parameters of the aforementioned composite waveform based on the obtained signals, including the amplitude and width of the anode pulse during the processing phase, the duration of the zero potential during the diffusion phase, and the amplitude, width, and application timing of the cathode reverse pulse during the impurity removal phase.

[0041] refer to Figures 1 to 9 The process of removing products during the near-atomic-scale electrolytic machining of 1nm nickel metal pores using this invention mainly includes the following steps:

[0042] Step 1: Connect an ultra-short pulse power supply with workpiece anode 1 as the positive electrode and tool cathode as the negative electrode.

[0043] Step 2: During processing, the applied anodic pulse (amplitude 250mV, pulse width 100ns) causes the nickel metal at anode 1 to undergo an electrochemical dissolution reaction under the influence of the electric field. The nickel ions generated during processing bind to the strong EDTA complexing agent 7 in the electrolyte, forming a high concentration of metal complex anions 8 at the ion channel outlet. Utilizing the ion concentration difference and electromigration between the inside and outside of MspA ion channel protein 5, the metal complex anions 8 are slowly diffused into the bulk solution, and the ultrashort pulse power supply is immediately shut off.

[0044] Step 3: During the diffusion phase, the applied voltage is zero or close to zero. Due to the high concentration gradient of complexed anions 8 formed during the processing phase, the complexed anions 8 actively diffuse towards the low-solubility bulk electrolyte. Using site-directed mutagenesis, specific amino acid residues on the inner wall of the MspA ion channel protein 5 are replaced with negatively charged glutamate residues. Figure 8 A comparison of the amino acid sequence of MspA ion channel protein 5 (SEQ ID NO.1 after gene mutation) with the amino acid sequence of MspA ion channel protein 5 (SEQ ID NO.2 before mutation) is presented. Figure 9 Gel electrophoresis and high-resolution electron microscopy images of the mutated MspA ion channel protein during isolation and purification are presented, showing that the inner wall of the channel exhibits negative charge under the pH conditions of the processing electrolyte. Under the influence of charge repulsion, the randomly diffused complexed anion 8 moves away from the inner wall of the ion channel, preventing the complexed anion 8 from adsorbing onto the inner wall.

[0045] Step 4: During the impurity removal phase, a reverse cathode pulse (amplitude -500mV, pulse width 500ns) is applied. Under the influence of the electric field, the complexed anion 8 electromigrates towards the tool cathode. Due to the combined effects of electrostatic repulsion and electromigration, the complexed anion 8 during the diffusion and impurity removal phases is difficult to adsorb onto the inner wall of the ion channel, reducing its transport resistance and adsorption probability within the channel, and is rapidly expelled from the MspA ion channel protein.

[0046] Step 5: At the same time, the current monitoring unit collects the current signal of the ion channel during the processing and feeds the signal back to the control system. The control system adaptively adjusts the output parameters of the pulse power supply unit according to the changes in the signal.

[0047] Step 6: After the predetermined time is reached, the processing is completed, and the processing result is as follows. Figure 7 As shown, the pore size is approximately 1 nm.

[0048] Example 2

[0049] This comparative example aims to demonstrate that if only simple DC voltage processing is used, and the electrolyte does not contain additives that can complex metal ions (i.e., the “chemical regulation” and “pulse regulation” methods of this invention are missing), near-atomic scale processing will cause the processing to stop momentarily due to product blockage.

[0050] System configuration: A 0.5 mol / L pure sodium chloride (NaCl) aqueous solution is used. This electrolyte does not contain any complexing agents (such as EDTA); the ion channel protein used is wild-type MspA protein without any electrical modifications, whose inner wall charge state is a natural property, and no "interfacial electrostatic repulsion" mechanism is introduced; the processing power supply is a simple DC regulated power supply, outputting a constant +0.4V anode voltage, completely lacking the "processing-diffusion-impurity removal" complex pulse waveform described in this invention.

[0051] Processing and Failure Phenomena: Within an extremely short time (on the order of milliseconds) after energization, a momentary current peak can be observed through the current monitoring unit, indicating that the anodic dissolution reaction of nickel has begun. This current peak then rapidly decays, dropping to an extremely low level close to zero within seconds, for example, at... Figure 11 During the reaction, the current dropped sharply after about 4 seconds, quickly reaching zero, and no related processing traces were detected in the TEM. Figure 10 This phenomenon indicates that the conductivity of the processing channel has decreased sharply, and the reaction has almost stopped.

[0052] Example 3:

[0053] A deep hole less than 10 nanometers deep and less than 5 nanometers in diameter is machined on the surface of titanium. Titanium is highly passivable, and the Ti produced during machining... 4+ A dense TiO2 passivation film will rapidly form, causing the processing to terminate immediately. This embodiment achieves stable and continuous nanomachining of titanium alloys through a synergistic strategy.

[0054] System configuration and parameter details: Electrolyte: 1.0 mol / L sodium citrate (C6H5Na3O7) aqueous solution. Citrate ions are Ti... 4+ It is a strong complexing agent that can form stable and soluble [Ti(C6H5O7)3]. 10- Complexing anions. Ion channel protein: using wild-type α-hemolysin (α-HL) protein ( Figure 12 The amino acid sequence of the titanium metal is shown in SEQ ID NO.3. The naturally occurring amino acid residues on its inner wall (such as aspartic acid and glutamic acid) provide sufficient negative charge at neutral pH. Pulse parameters: Processing phase: Anode pulse, amplitude +0.5 V, pulse width 100 ns. Diffusion phase: Zero potential interval, duration 300 ns. Impurity removal phase: Cathode reverse pulse, amplitude -1.0 V, pulse width 150 ns. Information on the processing depth of the titanium metal was obtained through fibrillation cross-section sampling. The processing depth was 5-8 nm. The TEM images of the processed cross-section are shown below. Figure 13 As shown.

[0055] Detailed workflow and principles of the synergistic excretion method:

[0056] 1. Chemical complexation: Under a high anodic overpotential of +0.5V, titanium dissolves to form Ti. 4+ The citrate ions in the electrolyte immediately complex with it, forming a strongly negatively charged [Ti(C6H5O7)3] 10- This move fundamentally prevented Ti from... 4+ It reacts with water to form a TiO2 passivation film, transforming the uncontrollable passivation reaction into a controllable dissolution-complexation reaction.

[0057] 2. Pulsed Electric Field Regulation: After processing, the concentration of the complex at the channel opening increases sharply. During the diffusion phase (300 ns), relying on the large concentration gradient formed, the complexed anions diffuse into the low-concentration bulk solution. During the impurity removal phase, a -1.0V cathode pulse generates a strong electromigration force, driving the negatively charged titanium-citric acid complex to migrate rapidly out of the channel. This pulse design creates a sufficient time window and driving force for the removal of highly reactive titanium dissolution products, preventing their accumulation at the channel opening.

[0058] 3. Interfacial electrostatic repulsion: The negative charge of the α-HL protein's inner wall generates a strong electrostatic repulsion force between it and the strongly negatively charged titanium-citric acid complex. This repulsion effectively prevents the adsorption or retention of larger complex anions on the channel inner wall, ensuring unobstructed transport pathways.

Claims

1. A method for the coordinated removal of products from near-atomic-scale electrochemical processing, characterized in that, A workpiece anode is provided, and a phospholipid bilayer insulating mask is constructed on its surface; the workpiece anode with the phospholipid bilayer constructed on its surface is placed in an electrolyte; By synergistically employing chemical complexation, pulsed electric fields, and interfacial electrostatic repulsion, the mass transfer process within the processing channel is actively managed. Specifically, this includes: adding a sufficient amount of strong complexing agent to the electrolyte to convert metal ions generated during the anodic dissolution of the workpiece into soluble negatively charged complexed anions in situ; applying a composite pulsed voltage waveform encompassing the processing phase, diffusion phase, and impurity removal phase, where localized anodic dissolution is performed during the processing phase, the diffusion phase utilizes the concentration gradient to drive the outward diffusion of products, and the impurity removal phase accelerates the removal of retained products through the electromigration effect of the cathode reverse pulse; and simultaneously, negatively modifying the inner wall of the ion channel protein to reduce the transport resistance and adsorption probability of negatively charged complexed anions within the channel through electrostatic repulsion.

2. The method according to claim 1, characterized in that, The strong complexing agent is a compound capable of forming stable, soluble complex anions with the target metal ions; and its concentration in the electrolyte is sufficient to complex all or most of the target metal ions generated during the processing in real time.

3. The method according to claim 1, characterized in that, The parameters of the composite pulse voltage waveform are configured to satisfy the following: the duration of the diffusion period is sufficient to allow the product to diffuse significantly by means of the concentration gradient; and the parameters of the cathode reverse pulse during the impurity removal period are sufficient to effectively remove the negatively charged complexed anion product through electromigration.

4. The method according to claim 1, characterized in that, The processing channels formed by the ion channel protein or its functional analogues are sized to allow the passage of electrolyte ions and the complexed anion products.

5. The method according to claim 1, characterized in that, The electrostatic repulsion method includes modifying the inner wall of the processing channel to make it exhibit the same electrical properties as the product ions in the processing environment.

6. A near-atomic-scale electrochemical machining system for implementing the method of any one of claims 1 to 5, characterized in that, include: An electrolytic cell unit for containing an electrolyte, wherein a strong complexing agent and ion channel proteins are added to the electrolyte; The working electrode unit includes a workpiece as an anode and a tool electrode as a cathode, wherein a phospholipid bilayer insulating mask is constructed on the anode surface of the workpiece; A pulse power supply unit, connected to the working electrode unit, is used to output the composite pulse voltage waveform; A control system, connected to the pulse power supply unit, is used to set and regulate the parameters of the waveform; The current monitoring unit is used to monitor the current signal in the processing channel in real time and feed it back to the control system.

7. The system according to claim 6, characterized in that, The current monitoring unit includes a source meter with fA-level accuracy and a transimpedance gain of 10. 5 -10 9 Transimpedance amplifiers and high-speed oscilloscopes with a voltage of V / A.

8. The application of the method according to any one of claims 1 to 5 in near-atomic scale processing of easily passivated metallic materials, characterized in that, The easily passivated metal material is copper, iron, aluminum, chromium, nickel, titanium, or an alloy thereof.

9. A method for near-atomic-scale electrolytic processing using the system described in claim 6 or 7, characterized in that, Includes the following steps: A workpiece anode with a phospholipid bilayer on its surface is provided; the workpiece anode is placed in an electrolyte containing a strong complexing agent and ion channel proteins; The composite pulse voltage waveform is output by setting the pulse power supply through the control system. Once the processing is started, the current signal is monitored in real time and the pulse parameters are dynamically adjusted to ensure that the reaction products are continuously discharged under the synergistic effect of concentration gradient, electromigration force and electrostatic repulsion force.

10. The system or method according to claim 6 or 9, characterized in that, The phospholipid bilayer is formed by immersing the anode in a phosphate buffer containing dioleoylphosphatidylcholine, artificial phospholipids, natural phospholipids, or block polymers.

Images