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CN-122013205-A - Near-atomic-scale electrolytic machining method based on interface self-assembled biological mask

CN122013205ACN 122013205 ACN122013205 ACN 122013205ACN-122013205-A

Abstract

The near-atomic-scale electrolytic machining process based on self-assembled biological mask includes the first hydroxylation pretreatment of the anode surface of workpiece, covering organic solvent phase containing phospholipid monomer onto the anode surface, introducing water phase electrolyte drop, and forming one layer of ultrathin, continuous and stable phospholipid supporting bilayer mask on the workpiece surface in situ with the molecular self-assembling driving force of the three-phase interface of oil-water-metal. Then, biological nano-channels are embedded in the bionic mask to construct a finite field ion transmission path. Finally, a precise pulse electric field is applied to drive electrolyte ions to be strictly limited in the nano channel and transmitted to the surface of the workpiece, and local anodic dissolution is initiated, so that the removal of the nano or near-atomic scale localized material is realized. The method solves the technical bottleneck that the high-quality phospholipid bilayer is difficult to prepare on the surface of the high-surface-energy metal, and provides a new way for ultra-precise electrolytic machining.

Inventors

  • XU ZHENGYANG
  • XIAO YOUPING

Assignees

  • 南京航空航天大学

Dates

Publication Date
20260512
Application Date
20260113

Claims (10)

  1. 1. A near-atomic-scale electrolytic machining method based on an interface self-assembled biological mask is characterized by comprising the steps of S1, in-situ forming of the interface self-assembled mask, covering an organic solvent phase containing phospholipid monomer on the surface of a workpiece anode subjected to hydroxylation pretreatment, introducing aqueous electrolyte droplets into the organic solvent phase to enable the aqueous electrolyte droplets, the organic solvent phase and the surface of the workpiece anode to form a three-phase interface, utilizing molecular self-assembled driving force at the three-phase interface to form a layer of supporting phospholipid bilayer serving as a dynamic mask on the surface of the workpiece anode in situ, S2, integrating a nano ion channel, namely embedding biological nano channels into the supporting phospholipid bilayer to form a finite ion transmission path, and S3, in-situ electrochemical machining, using the workpiece anode integrated with the biological nano channels as an electrode, applying a pulse electric field, driving electrolyte ions to be transmitted to the surface of the workpiece through the biological nano channels, and triggering local anode dissolution, so that near-atomic-scale localized material removal is realized.
  2. 2. The method according to claim 1, characterized in that in step S1 the contact time of the aqueous electrolyte droplets in the organic solvent phase with the surface of the workpiece anode is controlled to promote the formation of a continuous, intact layer of the supporting phospholipid bilayer.
  3. 3. The method according to claim 1, wherein the organic solvent phase is prepared by dissolving a phospholipid monomer in an organic solvent that is immiscible with the aqueous electrolyte, wherein the organic solvent is selected from the group consisting of a non-volatile organic solvent that is at least one of hexadecane, decane, tetradecane, squalene, and silicone oil.
  4. 4. A method according to claim 3, wherein the concentration of the phospholipid monomer in the organic solvent phase is from 5mg to 50mg/mL.
  5. 5. The method according to claim 1, wherein the hydroxylation pretreatment is performed by plasma treatment or ultraviolet treatment, and the mixed gas used in the plasma treatment contains an easy hydroxylation gas and an inert gas, and the hydroxyl group density of the anode surface of the workpiece is controlled by adjusting the plasma power and the treatment time.
  6. 6. The method of claim 1, wherein the biological nanochannel is an ion channel protein, an engineered polypeptide pore, or a biomimetic nanopore constructed based on DNA origami.
  7. 7. The method according to claim 1, characterized in that in step S1 successful formation of the mask is confirmed by monitoring the membrane capacitance or impedance change during formation of the supporting phospholipid bilayer.
  8. 8. The method of claim 7, wherein the monitoring process is performed in an electromagnetically shielded environment.
  9. 9. A near-atomic-scale electrochemical machining device for implementing the method according to any one of claims 1-8, comprising an electrolytic cell (1) containing a phospholipid-containing organic solution (8), a stage (5) arranged at the bottom of the electrolytic cell, a workpiece anode (7) arranged on the stage (5), a Faraday shielding box covered on the workpiece anode (7), a pipette cathode (2) arranged above the workpiece anode (7) through the Faraday shielding box (4), wherein the pipette cathode (2) and the workpiece anode (7) are respectively connected with an electrochemical workstation (3), the electrochemical workstation (3) applies a pulse electric field and monitors electric signals, and the pipette cathode (2) is used for controllably introducing liquid drops of the electrolyte (6) into the phospholipid-containing organic solution (8).
  10. 10. A workpiece, characterized in that its surface is formed with features of near atomic scale by the method of any of claims 1-8.

Description

Near-atomic-scale electrolytic machining method based on interface self-assembled biological mask Technical Field The invention relates to the field of electrochemical machining, in particular to a near-atomic-scale electrochemical machining method based on an interface self-assembled biological mask. Technical Field The support phospholipid bilayer serves as the basic scaffold for cell membranes and is considered to be an ideal mask material for near-atomic-scale electrolytic processing due to its inherent molecular-scale thickness (about 5 nm), excellent self-sealing properties, and natural compatibility with biological ion channel proteins. The core function is to serve as an ultrathin and insulating dynamic barrier, and limit the electrochemical reaction to the nanometer or even near atomic scale. However, the practical progress of this technology faces a fundamental challenge in how to efficiently and nondestructively prepare high quality support phospholipid bilayer on the surface of metal workpieces (particularly high surface energy metals commonly used in electrolytic processing) unsuitable for conventional film forming processes. Currently, classical methods of constructing supported phospholipid bilayer, such as vesicle fusion, solvent assisted and droplet contact methods, are strongly dependent on the nature of the substrate. Numerous studies (e.g., Mingeot-Leclercq M-P, Deleu M, Brasseur R, et al. Atomic force microscopy of supported lipid bilayers[J]. Nature Protocols, 2008, 3(10): 1654-1659.） show that vesicle fusion is effective on substrates such as mica, silicon oxide, silicon nitride and low surface energy metal gold, however, for high surface energy metal workpieces such as Fe, ni, cr, ti, al and alloys thereof widely used in electrolytic processing, vesicles are difficult to effectively break and spread into a uniform continuous phospholipid bilayer due to the extremely high interfacial energy barrier, even if a buffer such as Mg 2+、Ca2+ is added in the vesicle solution to promote vesicle breaking is very little effective on high surface energy metals and cannot realize complete or uniform breaking spreading, the core idea of Chinese inventions CN102749239A and CN105448698B is based on the vesicle fusion method to construct phospholipid membranes on specific support substrates (such as indium tin oxide conductive glass), and the problem of film formation of high surface energy metal workpieces cannot be solved. On the other hand, solvent assisted methods require a flowing electrolyte environment, which introduces uncontrollable factors for near atomic scale processing that seek localized precision, which is clearly disadvantageous. Whereas typical drop contact methods (such as Leptihn S, Castell O K, Cronin B, et al. Constructing droplet interface bilayers from the contact of aqueous droplets in oil[J]. Nature Protocols, 2013, 8(6): 1048-1057.） are generally applicable to hydrogels or moisture-rich substrates, they cannot migrate directly to the metal surface to achieve reliable support of the bilayer. In addition, although chinese invention CN113321815A explores the construction of stable phospholipid layers on the surface of MOF materials by chemical grafting, which forms self-assembled monolayers by n-octadecyl phosphate and combines with lecithin, etc., this process takes up to 24-28 hours, and introduces heterogeneous chemical components (e.g. cholesterol as stabilizer), whose complex interfacial chemistry may cause unpredictable interference to the subsequent electrochemical processing environment, and is difficult to meet the requirements of efficient and pure processing. The self-assembly behavior of phospholipid molecules at the interface is greatly controlled by interfacial energy and hydration. Studies show that (for example Ferhan A R, Yoon B K, Park S, et al. Solvent-assisted preparation of supported lipid bilayers[J]. Nature Protocols, 2019, 14(7): 2091-2118.）,, by creating a proper interfacial hydration environment, amphipathic phospholipid molecules can be spontaneously assembled under the drive of interfacial tension, the hydroxylation treatment of the metal surface is a key way for regulating and controlling the surface characteristics of the amphipathic phospholipid molecules and enhancing the adsorption of water molecules so as to create favorable film forming conditions, and hydroxyl (-OH) groups on the metal surface not only can change the interfacial energy, but also can provide a 'template' for orderly assembly of phospholipid molecules through specific interactions with metals. Therefore, based on self-assembly theory, energy minimization principle and surface hydroxyl chemistry, an innovative strategy is provided, and the aim is to solve the long-term difficult problem of nondestructive and rapid spreading of a phospholipid bilayer on the surface of a high-surface-energy metal workpiece. The method is focused on constructing an ideal interface for the functional