Surface conductive type self-repairable airplane discharge brush and preparation method thereof

Abstract

The application discloses a surface conductive type self-repairable airplane discharge brush and a preparation method thereof. The discharge brush comprises, from inside to outside, an insulating base material core rod, a micro-channel network arranged in the surface layer of the insulating base material core rod, a conductive repair liquid filled in the micro-channel network, a separation layer coated on the surface of the micro-channel network, a conductive continuous layer arranged on the separation layer, an inner layer heat shrink tube wrapped on the outside of the conductive continuous layer, and an outer layer heat shrink tube wrapped on the outside of the inner layer heat shrink tube. The surface conductive continuous layer and the built-in micro-channel repair liquid network are cooperated to make the discharge brush automatically seep and solidify the conductive repair liquid under capillary action when cracks are generated on the surface conductive layer, so that the conductive path is recovered, the self-repairing ability of the discharge brush is given, the problem that the existing discharge brush cannot be repaired and can only be replaced as a whole is solved, the service life is significantly prolonged, and the maintenance cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of aircraft electrostatic protection technology, and in particular to a surface-conductive self-healing aircraft discharge brush and its preparation method. Background Technology

[0002] Aircraft discharge brushes are electrostatic discharge devices installed on the pointed ends of aircraft wings, tail fins, and other similar components. Their core function is to continuously release static electricity generated during flight through friction with air and clouds, preventing static buildup from interfering with avionics and reducing the risk of lightning strikes. If static electricity cannot be released in time, accumulated charge can ignite fuel vapors, interfere with critical electronic equipment such as navigation and communication systems, and even damage composite material structures like radomes, seriously threatening flight safety. Therefore, discharge brushes are a key component in aircraft airworthiness certification.

[0003] Existing aircraft discharge brushes are typically made of carbon fiber composite materials and installed at locations such as the aircraft's trailing edge. Their structure is mostly a two-piece, replaceable design, with the conductor located inside the discharge brush and encased in an insulating layer. This structure has the following problems: When discharge brushes are subjected to impacts, aerodynamic particle erosion, or other external damage during use, the conductive path may break or be damaged, causing the brush to lose its electrostatic discharge function. Since existing discharge brushes lack self-repair capabilities, they must be replaced entirely after such damage, making on-site repair impossible. This not only increases airline maintenance costs and spare parts inventory pressure but may also cause flight delays due to waiting for replacement brushes, impacting operational efficiency. The problem of untimely spare parts supply is particularly pronounced for aircraft operating routes to remote areas.

[0004] Furthermore, while there are existing reports on self-healing conductive coatings, they are mostly applied in general materials fields, and the repair mechanism typically relies on pre-embedded microcapsules. When used in aircraft discharge brushes, this approach has the following drawbacks: microcapsules are difficult to distribute uniformly during the molding of the brush's slender rod-like structure, and once a capsule ruptures, the area loses its ability to repair itself, failing to meet the requirements of aerospace devices for repeated damage repair and high reliability. Additionally, existing self-healing conductive coatings only address the restoration of conductivity, without addressing the damage repair of the discharge brush substrate structure. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a surface-conductive, self-healing aircraft discharge brush and its preparation method. This invention constructs a synergistic structure of a surface conductive layer and a built-in microchannel repair fluid network. When the surface conductive layer is damaged and cracks occur, the conductive repair fluid automatically seeps out and solidifies under capillary action, restoring the conductive pathway. This endows the discharge brush with self-healing capabilities, solving the problem that existing discharge brushes cannot be repaired and must be replaced entirely, significantly extending service life and reducing maintenance costs.

[0006] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution: This invention provides a surface-conductive, self-healing aircraft discharge brush, comprising, from the inside out: Insulating substrate core rod; A microchannel network is formed inside the surface layer of the insulating substrate core rod, and the microchannel network is filled with a conductive repair fluid. An isolation layer is disposed on the surface of the microchannel network to enclose the conductive repair fluid within the microchannel network. A conductive continuous layer is disposed on the isolation layer and is a continuous conductive thin film layer covering the microchannel network; The inner heat shrink tubing covers the outside of the conductive continuous layer; The outer heat shrink tubing covers the outside of the inner heat shrink tubing.

[0007] Furthermore, the wall thickness of the inner heat shrink tubing is set to form part of the damage triggering threshold. Only when damage penetrates the inner heat shrink tubing and the conductive continuous layer from the outside to the inside and extends to the microchannel network, the conductive repair fluid is triggered to penetrate into the crack caused by the damage through capillary action.

[0008] Furthermore, the distance between the top of the microchannel network and the bottom of the conductive continuous layer is 50-100 μm.

[0009] Furthermore, the design parameters of the microchannel network are as follows: The channel depth is 0.3-0.5mm; The channel width is 100-200μm; The grid spacing is 2-5mm.

[0010] Furthermore, the conductive repair solution comprises the following components in parts by weight: Polyurethane prepolymer with isocyanate end groups, 60-70 parts; Nano silver wire, 15-25 parts; Diluent, 10-14 parts; Latent curing agent, 3-5 parts; The conductive repair liquid is liquid at room temperature with a viscosity of 50-200 mPa·s. It undergoes moisture solidification upon contact with moisture in the air, forming a conductive polymer network.

[0011] Furthermore, the insulating substrate core rod is made of polyetherimide or modified polyetherimide containing dynamic disulfide bonds. When the modified polyetherimide is used, the mass fraction of the disulfide bonds is 8%-12%.

[0012] Furthermore, when the insulating substrate core rod is made of modified polyetherimide containing dynamic disulfide bonds, under heating conditions of 80-120°C, the broken disulfide bonds undergo a reversible exchange reaction, realizing the self-healing of microcracks in the substrate, forming a dual protection with the conductive repair liquid for repairing the conductive function.

[0013] Furthermore, the microchannel network is made by a thermoforming process, and its shape is distributed in a grid or spiral pattern below the surface of the insulating substrate core rod.

[0014] Furthermore, when the damage penetrates the inner heat-shrink tubing and the conductive continuous layer and extends to the microchannel network, the conductive repair fluid penetrates upward into the crack under capillary action, solidifies upon contact with moisture in the air, and repairs the conductive pathway; the microchannel network covers the entire surface of the discharge brush in a grid pattern, and can trigger repair multiple times.

[0015] Another aspect of the present invention provides a method for preparing a surface-conductive self-healing aircraft discharge brush, comprising the following steps: The insulating substrate core rod is prepared using polyetherimide or modified polyetherimide; A microchannel network is formed inside the surface layer of the insulating substrate core rod; Fill the microchannel network with conductive repair fluid; An isolation layer is coated on the surface of the microchannel network filled with the conductive repair fluid to enclose the conductive repair fluid within the microchannel network; A conductive solution is coated on the isolation layer, and after curing, a conductive continuous layer is formed, which covers the microchannel network. An inner heat-shrink tubing is wrapped around the outside of the conductive continuous layer; An outer heat shrink tubing is wrapped around the inner heat shrink tubing.

[0016] The beneficial effects of this invention are as follows: (1) In this invention, the microchannel network is set below the conductive continuous layer, and the conductive repair fluid has the shortest path to penetrate the crack from the channel; the inner heat shrink tube is wrapped around the outside of the conductive continuous layer, and its wall thickness limits the additional thickness required for the damage to penetrate from the outer surface to the microchannel network. This means that the conductive repair fluid is only triggered to penetrate the crack upward for repair when the damage penetrates the inner heat shrink tube and the conductive continuous layer and extends to the microchannel network. This effectively prevents the conductive repair fluid from being wasted due to minor damage and ensures that the conductive repair fluid is reserved for deep damage that truly affects the conductivity.

[0017] (2) The microchannel network in this invention covers the entire surface of the discharge brush in a grid pattern. Regardless of where the damage occurs, there is a reserve of repair fluid below or in the adjacent area, eliminating repair blind spots. When the same location is damaged again and the damage extends to adjacent grid channels, the closed structure (isolation layer) of the adjacent channel is destroyed, and the conductive repair fluid penetrates into the new damaged area through capillary action, enabling the discharge brush to have multiple self-repair capabilities. Furthermore, the conductive repair fluid in this invention solidifies at room temperature after contact with moisture in the air, restoring the conductive path without the need for heating or external triggering conditions.

[0018] (3) The five-layer structure in this invention works synergistically in terms of spatial layout and physical function. The conductive continuous layer is set on the outer surface of the insulating substrate core rod and the microchannel network is opened inside the surface layer of the insulating substrate core rod, forming a direct correspondence between the damage and the repair source; the inner heat shrink tube limits the triggering interval between the microchannel network opening and the conductive continuous layer, and its binding force exerts a squeezing effect on the repair fluid, which is superimposed with the capillary effect of the microchannel itself, driving the conductive repair fluid into the crack; when the insulating substrate core rod is made of modified polyetherimide containing dynamic disulfide bonds, the reversible exchange reaction of disulfide bonds in the substrate under heating conditions realizes the self-healing of microcracks in the substrate, which, together with the repair of the conductive function by the conductive repair fluid, acts on the two dimensions of substrate structure and conductive pathway, respectively, complementing each other in terms of the repair object and forming dual protection. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the cross-sectional structure of the surface conductive self-healing aircraft discharge brush of the present invention.

[0020] In the figure, 10: insulating substrate core rod; 20: microchannel network; 30: isolation layer; 40: conductive continuous layer; 50: inner heat shrink tubing; 60: outer heat shrink tubing. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] The present invention provides a surface conductive self-healing aircraft discharge brush, which includes, from the inside out, an insulating substrate core rod 10, a microchannel network 20, an isolation layer 30, a conductive continuous layer 40, an inner heat shrink tubing 50, and an outer heat shrink tubing 60.

[0023] The insulating substrate core rod 10, which serves as the structural support for the discharge brush, is made of polyetherimide. Polyetherimide has a glass transition temperature of approximately 215°C and exhibits excellent high-temperature resistance, mechanical strength, and flame-retardant properties, meeting the environmental requirements for use in aerospace devices.

[0024] Preferably, the insulating substrate core rod 10 is made of modified polyetherimide containing dynamic disulfide bonds. The dynamic disulfide bonds endow the substrate with self-healing capabilities under specific conditions. To ensure a balance between self-healing capability and material mechanical properties, the mass fraction of disulfide bonds in the modified polyetherimide is preferably 8%-12%. When the insulating substrate core rod 10 develops microcracks due to external force or fatigue, under heating conditions of 80-120°C, the broken disulfide bonds undergo a reversible exchange reaction. That is, after the molecular chain motion is activated, the disulfide bonds on different chains re-pair to form new cross-linked connections, the molecular chains re-entangle, the cracks are healed, and the mechanical properties of the substrate can be restored to 80%-95% of the original material.

[0025] The microchannel network 20 is formed inside the surface layer of the insulating substrate core rod 10, and is distributed in a grid or spiral pattern below the surface of the core rod to store the conductive repair fluid. For example, the design parameters of the microchannel network 20 are as follows: channel depth 0.3-0.5 mm, channel width 100-200 μm, and grid spacing 2-5 mm.

[0026] The microchannel network 20 is preferably prepared by a thermoforming process. Specifically, the polyetherimide substrate is heated above its glass transition temperature to soften its surface. Pressure is applied to the softened surface using a mold pre-processed with a mesh-like or spiral micro-protrusion structure. After cooling below the glass transition temperature to re-harden and shape the substrate, it is demolded, and the microchannels are permanently formed inside the surface layer of the insulating substrate core 10. This process precisely controls the channel depth, width, and spacing through the mold, ensuring batch production consistency of the channel dimensions.

[0027] The conductive repair solution is filled within the microchannel network 20. It is liquid at room temperature, with a preferred viscosity of 50-200 mPa·s to ensure good flowability and capillary penetration within the microchannels. Exemplarily, the conductive repair solution comprises the following components in parts by weight: 60-70 parts of a polyurethane prepolymer with isocyanate end groups, 15-25 parts of silver nanowires, 10-14 parts of a diluent, and 3-5 parts of a latent curing agent. The diluent is selected from at least one of reactive or inactive diluents; the reactive diluent has both viscosity-reducing and curing-participating functions, preferably propyl carbonate or propylene oxide butyl ether; the inactive diluent is selected from at least one of anhydrous xylene or ethyl acetate. The latent curing agent is a moisture-activated latent curing agent, selected from one or more of aldehyde imines, ketimines, or oxazolidine compounds.

[0028] The conductive repair solution undergoes moisture curing upon contact with airborne moisture. The curing mechanism is as follows: the isocyanate end groups in the polyurethane prepolymer react with water molecules in the environment to generate amines and carbon dioxide. The amines further react with the isocyanates to form urea bonds. As the urea bond cross-linking network is established, the conductive repair solution gradually loses its fluidity and solidifies into a polyurethane-urea copolymer with a three-dimensional network structure. Simultaneously, the silver nanowires dispersed in the conductive repair solution are embedded in the polymer matrix and come into contact with each other, forming continuous conductive pathways, thereby restoring conductivity while repairing cracks. This curing mechanism has mild reaction conditions and can be completed at room temperature, making it suitable for the maintenance of aircraft discharge brushes.

[0029] An isolation layer 30 is coated on the surface of the microchannel network 20, encapsulating the conductive repair fluid within the microchannel network 20. The isolation layer 30 is an extremely thin, inert coating that only serves to isolate the conductive solution during the preparation process. Its thickness is extremely thin (micrometer level), and it has no load-bearing capacity. When the crack extends to this point, it is easily penetrated and destroyed, and does not constitute a barrier to the leakage of the repair fluid.

[0030] A conductive continuous layer 40 is disposed above the isolation layer 30 and is a continuous conductive thin film layer covering the microchannel network 20. This layer is formed by coating a conductive solution onto the isolation layer 30 and allowing it to cure to form a continuous conductive film. The microchannel network 20 is disposed below the conductive continuous layer 40, minimizing the path for the conductive repair fluid to penetrate the crack. The conductive continuous layer 40 serves both as a daily electrostatic discharge function and as an essential path for crack propagation; its fracture is a critical step in triggering repair.

[0031] An inner heat-shrink tubing 50 is wrapped around the conductive continuous layer 40. The wall thickness of the inner heat-shrink tubing 50 is set to constitute part of the damage triggering threshold, that is, its wall thickness to a certain extent defines the additional thickness required for damage to penetrate from the outer surface to reach the microchannel network 20. For example, the distance between the top of the channel of the microchannel network 20 and the bottom of the conductive continuous layer 40 is preferably 50-100 μm.

[0032] The wall thickness ensures that minor everyday scratches are insufficient to trigger the release of the repair fluid due to the barrier effect of the inner heat-shrink tubing 50. This effectively prevents the conductive repair fluid from being wasted due to minor damage, ensuring that the conductive repair fluid is reserved for deeper damage that truly affects conductivity. Only when the damage penetrates the inner heat-shrink tubing 50, the conductive continuity layer 40, and the insulating layer 30, and extends to the microchannel network 20, is the conductive repair fluid triggered to penetrate into the crack caused by the damage triggered by capillary action. This creates a mechanical trigger threshold at the structural level that requires no external sensors.

[0033] In addition, the tightening force of the inner heat shrink tubing 50 can exert a radial compression effect on the underlying structure. This compression force, combined with the capillary effect of the microchannel itself, drives the conductive repair fluid to actively enter the crack gap, thereby improving the filling speed and completeness of the conductive repair fluid.

[0034] The outer heat shrink tubing 60 covers the outside of the inner heat shrink tubing 50, providing weather-resistant protection for the discharge brush and ensuring that the internal functional layers are protected from direct environmental factors such as ultraviolet radiation, humidity, and salt spray during flight and ground parking.

[0035] The self-healing mechanism and synergistic effect of the surface-conductive self-healing aircraft discharge brush of the present invention are as follows: When the discharge brush is subjected to impact, aerodynamic particle erosion, or other external force damage during use, the damage extends from the outside in. If the damage only involves the outer heat-shrink tubing 60, it does not affect the discharge function. However, if the damage penetrates the inner heat-shrink tubing 50, the conductive continuous layer 40, and the isolation layer 30, and extends to the microchannel network 20, the closed structure of the microchannel network 20 is disrupted. The conductive repair fluid stored within it penetrates upwards into the crack gap under the combined action of capillary action and the extrusion pressure of the inner heat-shrink tubing 50. Simultaneously, the crack formed by the damage extends from the outer surface to the microchannel network 20, and moisture from the ambient air enters along the crack channels, contacting the isocyanate end groups in the seeping conductive repair fluid and initiating moisture curing. The cured polyurethane-urea copolymer matrix embeds silver nanowires, forming a conductive pathway within the crack and restoring the electrostatic discharge function of the discharge brush.

[0036] The microchannel network 20 covers the entire surface of the discharge brush in a grid pattern, ensuring that repair fluid is stored beneath or in the vicinity of any damage, eliminating repair blind spots. When the same location is damaged again and the damage extends to adjacent grid channels, the closed structure of the adjacent channels is disrupted, and conductive repair fluid seeps into the new damaged area through capillary action, enabling the discharge brush to have multiple self-repair capabilities.

[0037] The aforementioned effects are achieved through the synergistic cooperation of the six-layer structure in terms of spatial layout and physical function. The conductive continuous layer 40 is disposed above the isolation layer 30, forming a direct correspondence between the damage and repair source with the microchannel network 20. During the preparation process, the isolation layer 30 isolates the conductive solution from the conductive repair fluid. Due to its extreme thinness and brittleness, it is instantly penetrated when damage is triggered, without hindering the seepage of the repair fluid. The inner heat-shrink tubing 50 limits the trigger threshold with its wall thickness and promotes the delivery of the repair fluid with its binding force. When the insulating substrate core rod 10 is made of modified polyetherimide containing dynamic disulfide bonds, the substrate can achieve structural self-healing of microcracks in the substrate through a reversible exchange reaction of disulfide bonds under heating conditions of 80-120℃. This, along with the functional self-repair of the conductive pathway by the conductive repair fluid, acts on both the substrate structure and conductive function, complementing each other in terms of the repair object and triggering conditions, thus forming dual protection.

[0038] The preparation method of the above-mentioned surface conductive self-healing aircraft discharge brush includes the following steps: preparing an insulating substrate core rod 10 using polyetherimide or modified polyetherimide; heating the insulating substrate core rod 10 to above the glass transition temperature, hot-pressing it with a mold having a micro-protrusion structure, and forming a microchannel network 20 inside the surface layer of the insulating substrate core rod 10 after cooling and demolding; filling the microchannel network 20 with a conductive repair liquid; coating an isolation layer 30 on the surface of the microchannel network 20 filled with the conductive repair liquid to seal the conductive repair liquid inside the microchannel network 20; coating a conductive solution on the isolation layer 30, and after curing, forming a conductive continuous layer 40 that covers the microchannel network 20; wrapping an inner heat shrink tubing 50 around the conductive continuous layer 40; and wrapping an outer heat shrink tubing 60 around the inner heat shrink tubing 50 to obtain the final product.

[0039] The present invention will be further described below through specific embodiments.

[0040] Example

[0041] The discharge brush in this embodiment consists of six layers from the inside out: an insulating substrate core rod 10, a microchannel network 20, an insulating layer 30, a conductive continuous layer 40, an inner heat-shrink tubing 50, and an outer heat-shrink tubing 60. The insulating substrate core rod 10 is made of modified polyetherimide containing dynamic disulfide bonds, with a disulfide bond mass fraction of 10%. The core rod has a diameter of 6 mm and a length of 200 mm. The microchannel network 20 is formed inside the surface layer of the core rod through a hot-pressing process. Specifically, the core rod is heated to 220°C to soften its surface, and pressure is applied using a mold with a grid-like micro-protrusion structure on its surface. After holding the pressure and cooling to room temperature, the mold is removed, thus forming a grid-like microchannel network 20 with a depth of 0.4 mm, a width of 150 μm, and a grid spacing of 3 mm below the surface of the core rod. The microchannel network 20 is filled with a conductive repair fluid, which has a viscosity of 120 mPa·s at room temperature. This fluid is formulated with 65 parts by mass of a polyurethane prepolymer containing isocyanate end groups, 20 parts by mass of silver nanowires, 12 parts by mass of a diluent (propyl carbonate), and 3 parts by mass of a latent curing agent (aldecimid latent curing agent Aldirez A). An isolation layer 30 is coated onto the surface of the microchannel network 20 filled with the conductive repair fluid, sealing the fluid within the network. A conductive continuous layer 40, approximately 30 μm thick, is formed by coating and curing a conductive solution (polyurethane-based conductive silver paste) on top of the isolation layer 30. An inner heat-shrink tubing 50, with a wall thickness of 80 μm, is wrapped around the conductive continuous layer 40 after heat shrinking and tightly adhering to its surface. An outer heat-shrink tubing 60 is then wrapped around the inner heat-shrink tubing 50 to provide weather protection.

[0042] When the discharge brush of this embodiment encounters external impact or particle erosion during service, the damage extends from the outside in. If the damage is limited to the outer heat-shrink tubing 60, the discharge function is unaffected. When the damage penetrates the outer heat-shrink tubing 60, the inner heat-shrink tubing 50, the conductive continuous layer 40, and the isolation layer 30 and extends to the microchannel network 20, the closed structure of the microchannel network 20 is disrupted. The conductive repair fluid stored within it, driven by capillary action and the radial binding force of the inner heat-shrink tubing 50, permeates upwards into the crack gap from the microchannel. Simultaneously, the crack extends from the outer surface of the discharge brush to the microchannel network 20, forming an air inlet channel. Water molecules in the ambient air diffuse along this channel into the crack interior, contacting the isocyanate end groups in the exudated repair fluid and initiating a moisture-curing crosslinking reaction. The repair fluid gradually cures into a polyurethane-urea copolymer matrix at room temperature. The silver nanowires are embedded in the cured matrix and overlap to form a continuous conductive network, thereby repairing the conductive pathway at the break in the conductive continuous layer 40 and restoring the electrostatic discharge function of the discharge brush. Because the microchannel network 20 covers the entire mandrel surface in a grid pattern, regardless of where the damage occurs axially or circumferentially in the discharge brush, there is a reserve of repair fluid below or near the grid nodes. When the same location is damaged again and the damage extends to adjacent grid channels, the closed structure of the adjacent channels is disrupted, and the conductive repair fluid penetrates into the new damaged area through capillary action, giving the discharge brush multiple self-healing capabilities. When the substrate develops microcracks due to long-term fatigue or external force, heating the discharge brush to 100°C and holding it at that temperature for 45 minutes causes a reversible exchange reaction of the dynamic disulfide bonds in the modified polyetherimide, and the molecular chains re-entangle, healing the microcracks in the substrate and restoring the mechanical properties to more than 90% of their original state. This complements the moisture-curing conductive repair of the conductive repair fluid in terms of repair target and triggering conditions, forming a dual protection.

[0043] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0044] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A surface-conductive, self-healing aircraft discharge brush, characterized in that, From the inside out, the following are included: Insulating substrate core rod; A microchannel network is formed inside the surface layer of the insulating substrate core rod, and the microchannel network is filled with a conductive repair fluid. An isolation layer is disposed on the surface of the microchannel network to enclose the conductive repair fluid within the microchannel network. A conductive continuous layer is disposed on the isolation layer and is a continuous conductive thin film layer covering the microchannel network; The inner heat shrink tubing covers the outside of the conductive continuous layer; The outer heat shrink tubing covers the outside of the inner heat shrink tubing.

2. The surface-conductive self-healing aircraft discharge brush according to claim 1, characterized in that, The wall thickness of the inner heat shrink tubing is set to form part of the damage triggering threshold. Only when damage penetrates the inner heat shrink tubing and the conductive continuous layer from the outside to the inside and extends to the microchannel network, the conductive repair fluid is triggered to penetrate into the crack caused by the damage through capillary action.

3. The surface-conductive self-healing aircraft discharge brush according to claim 1 or 2, characterized in that, The distance between the top of the microchannel network and the bottom of the conductive continuous layer is 50-100 μm.

4. The surface-conductive self-healing aircraft discharge brush according to claim 1, characterized in that, The design parameters of the microchannel network are as follows: The channel depth is 0.3-0.5mm; The channel width is 100-200μm; The grid spacing is 2-5mm.

5. The surface-conductive self-healing aircraft discharge brush according to claim 1, characterized in that, The conductive repair solution comprises the following components in parts by weight: Polyurethane prepolymer with isocyanate end groups, 60-70 parts; Nano silver wire, 15-25 parts; Diluent, 10-14 parts; Latent curing agent, 3-5 parts; The conductive repair liquid is liquid at room temperature with a viscosity of 50-200 mPa·s. It undergoes moisture solidification upon contact with moisture in the air, forming a conductive polymer network.

6. The surface-conductive self-healing aircraft discharge brush according to claim 1, characterized in that, The insulating substrate core rod is made of polyetherimide or modified polyetherimide containing dynamic disulfide bonds. When the modified polyetherimide is used, the mass fraction of the disulfide bonds is 8%-12%.

7. The surface-conductive self-healing aircraft discharge brush according to claim 6, characterized in that, When the insulating substrate core rod is made of modified polyetherimide containing dynamic disulfide bonds, the broken disulfide bonds undergo a reversible exchange reaction under heating conditions of 80-120°C, realizing the self-healing of microcracks in the substrate, forming a dual protection with the conductive repair liquid for repairing the conductive function.

8. The surface-conductive self-healing aircraft discharge brush according to claim 1, characterized in that, The microchannel network is made by a thermoforming process and is distributed in a grid or spiral shape below the surface of the insulating substrate core rod.

9. The surface-conductive self-healing aircraft discharge brush according to claim 1, characterized in that, When damage penetrates the inner heat-shrink tubing and the conductive continuous layer and extends to the microchannel network, the conductive repair fluid penetrates upward into the crack under capillary action, solidifies upon contact with moisture in the air, and repairs the conductive pathway; the microchannel network covers the entire surface of the discharge brush in a grid pattern, and can be triggered for repair multiple times.

10. A method for preparing a surface-conductive self-healing aircraft discharge brush according to any one of claims 1-9, characterized in that, Includes the following steps: The insulating substrate core rod is prepared using polyetherimide or modified polyetherimide; A microchannel network is formed inside the surface layer of the insulating substrate core rod; Fill the microchannel network with conductive repair fluid; An isolation layer is coated on the surface of the microchannel network filled with the conductive repair fluid to enclose the conductive repair fluid within the microchannel network; A conductive solution is coated on the isolation layer, and after curing, a conductive continuous layer is formed, which covers the microchannel network. An inner heat-shrink tubing is wrapped around the outside of the conductive continuous layer; An outer heat shrink tubing is wrapped around the inner heat shrink tubing.

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