Electromagnetic shielding equipotential covering cloth and production process thereof

Abstract

The invention relates to the field of functional composite materials, and discloses electromagnetic shielding equipotential covering cloth which comprises a polyester fiber base cloth layer. The surface of the base cloth is coated with the conductive layer, and the conductive layer is composed of the following components in parts by mass: 10-15 parts of graphene oxide; 30 to 40 parts of ionic liquid; 40 to 50 parts of a self-repairing polyurethane prepolymer; 5 to 8 parts of fluorosilicone modified nano silicon dioxide; the hydrophobic layer covers the surface of the conducting layer and is formed by vapor deposition of a fluorine-containing silicon compound; the ionic liquid is 1-ethyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide salt, the surface of the fluorine-silicon modified nano silicon dioxide is treated by a silane coupling agent, and the mass ratio of the silane coupling agent to the nano silicon dioxide is (1: 10)-(1: 15). By adopting the technical scheme that ionic liquid intercalation cooperates with microwave directional reduction, efficient construction of a conductive network between graphene oxide layers is achieved, and the conductivity and the electromagnetic shielding effectiveness are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of functional composite materials, in particular to an electromagnetic shielding equipotential cover cloth and a production process thereof. Background Art

[0002] Electromagnetic shielding equipotential drapes are multilayered materials that combine a composite functional coating with a flexible substrate. Their core goal is to create a continuous, stable conductive network to eliminate differences in electromagnetic field distribution and block external interference. These drapes typically use flexible fabrics such as polyester and aramid as a substrate, with a conductive functional layer (such as graphene or metal nanowires) applied to the surface. A specific process is used to strengthen the interface between the conductive layer and the base fabric. The production process involves key steps such as conductive material dispersion, directional assembly, and interface modification, requiring a balance of conductivity, flexibility, and environmental tolerance.

[0003] In existing technologies, the construction of conductive layers mainly relies on three methods: first, dispersing conductive fillers (such as carbon black and silver powder) in a resin system and then coating and curing it to form a rigid conductive film; second, weaving metal fibers (such as copper wire and stainless steel wire) and blending them with a base fabric to form a conductive mesh structure; and third, depositing a metal coating (such as nickel and copper) on the surface of the base fabric using chemical plating or sputtering. For example, some solutions use epoxy resin-based conductive coatings and cure the conductive layer through high-temperature baking, but the coating is prone to microcracks due to differences in thermal expansion coefficients; other solutions improve conductivity by weaving a metal fiber mesh, but the rigidity of the metal fibers causes the conductive path to break when the fabric is bent.

[0004] A common drawback of these methods is functional degradation under dynamic usage scenarios. Both microcrack propagation in the coated conductive layer and interfacial delamination of the metal composite fabric can lead to localized failure of the conductive network, significantly reducing shielding effectiveness with increasing mechanical deformation. For example, repeated bending can cause cracking of the metal coating due to brittleness, while the conductive filler gradually aggregates due to creep in the resin matrix. Ultimately, this can cause the cover's shielding performance to drop by over 50% in high-frequency deformation scenarios, such as wearable devices. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides an electromagnetic shielding equipotential cover cloth and its production process, which solves the multifunctional coordination problems of the existing electromagnetic shielding equipotential cover cloth, such as the conductive network is prone to failure under dynamic deformation and environmental erosion, lack of self-repairing ability and insufficient hydrophobic protection.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: an electromagnetic shielding equipotential cover cloth, comprising:

[0007] Polyester fiber base fabric layer;

[0008] The conductive layer coated on the surface of the base fabric is composed of the following components in parts by mass:

[0009] 10-15 parts of graphene oxide;

[0010] 30-40 parts of ionic liquid;

[0011] 40-50 parts of self-repairing polyurethane prepolymer;

[0012] 5-8 parts of fluorine-silicon modified nano-silicon dioxide;

[0013] A hydrophobic layer covers the surface of the conductive layer, wherein the hydrophobic layer is formed by vapor deposition of a fluorine-containing silicon compound.

[0014] Preferably, the ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt.

[0015] Preferably, the surface of the fluorine-silicon modified nano-silica is treated with a silane coupling agent, and the mass ratio of the silane coupling agent to the nano-silica is 1:10 to 1:15.

[0016] Preferably, the self-healing polyurethane prepolymer contains dynamic disulfide bonds and has a molecular weight of 3000-5000 Da.

[0017] The present invention also provides a production process for an electromagnetic shielding equipotential cover cloth, comprising the following steps:

[0018] Step 1: mixing graphene oxide, ionic liquid, self-healing polymer and nano-modifier to prepare a conductive colloid;

[0019] Step 2: Plasma activation treatment of the polyester fiber base fabric;

[0020] Step 3: Applying the conductive colloid to the surface of the activated base fabric through an electrostatic spraying process;

[0021] Step 4: using microwave radiation to reduce and crosslink the coating;

[0022] Step 5: Perform hydrophobic strengthening treatment on the cured coating surface.

[0023] Preferably, the step 1 includes the following processing:

[0024] Dispersing graphene oxide in deionized water and ultrasonically treating for 30-60 minutes to obtain a dispersion with a solid content of 1-3 wt%;

[0025] The ionic liquid and the graphene oxide dispersion are mixed in a mass ratio of 3:1 to 4:1, magnetically stirred for 2 to 4 hours at a temperature of 60-70° C., and dehydrated under reduced pressure to a water content of ≤0.5 wt %;

[0026] Heat the self-repairing polyurethane prepolymer to 60-70°C and blend it with the mixture at a shear rate of 1000-1500s -1 , time 10-20 minutes;

[0027] Add fluorine-silicon modified nano-silica and mix in batches, with an interval of 2 to 3 minutes between each addition, and a total mixing time of 5-10 minutes.

[0028] Preferably, the step 2 includes:

[0029] The polyester fiber substrate is placed in an oxygen plasma treatment chamber, and oxygen gas with a purity of ≥99.99% is introduced at a gas flow rate of 20 to 30 sccm;

[0030] Start the RF power supply, control the power to 50 to 80 W, the processing time to 3 to 5 minutes, and the chamber pressure to 50 to 100 Pa;

[0031] The treated base fabric is transferred to the electrostatic spraying station for step three within ≤30 seconds.

[0032] Preferably, the step three includes:

[0033] Adjust the parameters of the electrostatic spraying equipment: spraying voltage 40-60kV, atomization pressure 0.3-0.5MPa, and the distance between the nozzle and the base fabric 15-25cm;

[0034] Control the amount of conductive colloid sprayed to make the wet film thickness 50-80μm;

[0035] After spraying, let it stand for 1-3 minutes to level. The ambient humidity should be ≤40% RH.

[0036] Preferably, the step 4 includes:

[0037] Place the sprayed substrate in a microwave reaction chamber, introduce inert gas nitrogen or argon with a gas purity of ≥99.99% and a chamber vacuum of 0.05-0.1 MPa;

[0038] Start microwave radiation, control the frequency to 2.45GHz±50MHz, and the power density to 0.5-0.8W / cm 2 , processing time 2-4 minutes;

[0039] Simultaneously monitor the coating temperature and control the peak temperature to ≤80℃.

[0040] Preferably, the step five includes:

[0041] The cured substrate is placed in a vacuum deposition chamber and hexamethyldisilazane vapor is introduced at a vapor concentration of 5-10 vol%;

[0042] The chamber temperature is controlled at 40-60°C, the vacuum degree is 0.05-0.1 MPa, and the processing time is 8-12 seconds;

[0043] After the treatment is completed, nitrogen is purged for 5-10 seconds at a pressure of 0.2-0.4 MPa.

[0044] The present invention provides an electromagnetic shielding equipotential cover cloth and its production process, which has the following beneficial effects:

[0045] 1. This invention utilizes an ionic liquid intercalation technique in conjunction with microwave-directed reduction to efficiently construct a conductive network between graphene oxide layers, significantly improving conductivity and electromagnetic shielding effectiveness. Compared to existing methods that rely solely on thermal reduction or physical intercalation, this method overcomes the technical drawbacks of insufficient conductivity and unstable post-reduction structures.

[0046] 2. This invention uses a synergistic effect based on dynamic bond reorganization and interfacial chemical anchoring to impart efficient self-healing capabilities and strong interfacial bonding to the coating. Conventional technologies using static cross-linking networks or processes without interfacial activation completely ineffectively self-heal and the coating easily peels off, failing to meet the dynamic durability requirements of flexible devices.

[0047] 3. This invention achieves a super-hydrophobic surface with high breathability by employing a coordinated design of nano-roughening and vapor deposition directional encapsulation. Existing dip coating or single chemical modification methods result in rapid hydrophobicity degradation or loss of breathability due to pore clogging or a lack of multi-level roughening.

[0048] 4. This invention utilizes cross-scale structural optimization combining conductive and hydrophobic layers to ensure the material's long-term stability in harsh environments. Traditional solutions, due to their single components or processes, are prone to interface degradation or functional failure under extreme conditions such as heat, humidity, and salt spray. This invention overcomes these limitations through a synergistic protection mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is one of the flow charts of the method of the present invention;

[0050] Figure 2 This is the second flow chart of the method of the present invention.

[0051] Among them, 1. Polyester fiber base fabric layer; 2. Conductive layer; 3. Hydrophobic layer. DETAILED DESCRIPTION

[0052] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the present specification. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0053] Please see the attached Figure 1 The embodiment of the present invention provides an electromagnetic shielding equipotential cover cloth, comprising:

[0054] Polyester fiber base fabric layer 1;

[0055] The conductive layer 2 coated on the surface of the base fabric is composed of the following components in parts by mass:

[0056] 10-15 parts of graphene oxide;

[0057] 30-40 parts of ionic liquid;

[0058] 40-50 parts of self-repairing polyurethane prepolymer;

[0059] 5-8 parts of fluorine-silicon modified nano-silicon dioxide;

[0060] The hydrophobic layer 3 covers the surface of the conductive layer 2, and the hydrophobic layer 3 is formed by vapor deposition of a fluorine-containing silicon compound.

[0061] The ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide.

[0062] The surface of the fluorine-silicon modified nano-silica is treated with a silane coupling agent, and the mass ratio of the silane coupling agent to the nano-silica is 1:10 to 1:15.

[0063] The self-healing polyurethane prepolymer contains dynamic disulfide bonds and has a molecular weight of 3000-5000 Da.

[0064] The production process of an electromagnetic shielding equipotential cover cloth described below can correspond to the electromagnetic shielding equipotential cover cloth described above.

[0065] Please see the attached Figure 2 , a production process of electromagnetic shielding equipotential cover cloth, comprising the following steps:

[0066] Step 1: mixing graphene oxide, ionic liquid, self-healing polymer and nano-modifier to prepare a conductive colloid;

[0067] Step 2: Plasma activation treatment of the polyester fiber base fabric;

[0068] Step 3: Applying the conductive colloid to the surface of the activated base fabric through an electrostatic spraying process;

[0069] Step 4: using microwave radiation to reduce and crosslink the coating;

[0070] Step 5: Perform hydrophobic strengthening treatment on the cured coating surface.

[0071] Step 1 includes the following processing:

[0072] Dispersing graphene oxide in deionized water and ultrasonically treating for 30-60 minutes to obtain a dispersion with a solid content of 1-3 wt%;

[0073] The ionic liquid and the graphene oxide dispersion are mixed in a mass ratio of 3:1 to 4:1, magnetically stirred for 2 to 4 hours at a temperature of 60-70° C., and dehydrated under reduced pressure to a water content of ≤0.5 wt %;

[0074] Heat the self-repairing polyurethane prepolymer to 60-70°C and blend it with the mixture at a shear rate of 1000-1500s -1 , time 10-20 minutes;

[0075] Add fluorine-silicon modified nano-silica and mix in batches, with an interval of 2 to 3 minutes between each addition, and a total mixing time of 5-10 minutes.

[0076] Step 2 includes:

[0077] The polyester fiber substrate is placed in an oxygen plasma treatment chamber, and oxygen gas with a purity of ≥99.99% is introduced at a gas flow rate of 20 to 30 sccm;

[0078] Start the RF power supply, control the power to 50 to 80 W, the processing time to 3 to 5 minutes, and the chamber pressure to 50 to 100 Pa;

[0079] The treated base fabric is transferred to the electrostatic spraying station for step three within ≤30 seconds.

[0080] Step three includes:

[0081] Adjust the parameters of the electrostatic spraying equipment: spraying voltage 40-60kV, atomization pressure 0.3-0.5MPa, and the distance between the nozzle and the base fabric 15-25cm;

[0082] Control the amount of conductive colloid sprayed to make the wet film thickness 50-80μm;

[0083] After spraying, let it stand for 1-3 minutes to level. The ambient humidity should be ≤40% RH.

[0084] Step 4 includes:

[0085] Place the sprayed substrate in a microwave reaction chamber, introduce inert gas nitrogen or argon with a gas purity of ≥99.99% and a chamber vacuum of 0.05-0.1 MPa;

[0086] Start microwave radiation, control the frequency to 2.45GHz±50MHz, and the power density to 0.5-0.8W / cm 2 , processing time 2-4 minutes;

[0087] Simultaneously monitor the coating temperature and control the peak temperature to ≤80℃.

[0088] Step five includes:

[0089] The cured substrate is placed in a vacuum deposition chamber and hexamethyldisilazane vapor is introduced at a vapor concentration of 5-10 vol%;

[0090] The chamber temperature is controlled at 40-60°C, the vacuum degree is 0.05-0.1 MPa, and the processing time is 8-12 seconds;

[0091] After the treatment is completed, nitrogen is purged for 5-10 seconds at a pressure of 0.2-0.4 MPa.

[0092] As an option, graphene oxide can be dispersed using an ultrasonic-assisted liquid-phase exfoliation method. For example, graphene oxide powder is added to deionized water and dispersed using a probe-type ultrasonic device. It should be noted that the high-frequency pressure waves generated by the ultrasonic treatment through the cavitation effect can break the interlayer van der Waals forces of graphene oxide, thereby obtaining a monolayer or oligolayer dispersion. In one possible implementation, the power range of the ultrasonic treatment can be adapted to the sheet size of the graphene oxide. For example, for graphene oxide with a sheet diameter of 1-5 μm, an ultrasonic power range of 200-500 W can be selected to ensure that the sheets are fully exfoliated and avoid excessive fragmentation.

[0093] Specifically, the ionic liquid acts as an intercalation agent and dispersion medium, and its cations (such as 1-ethyl-3-methylimidazolium cations) can be embedded in the graphene oxide interlayer, expanding the interlayer spacing by electrostatic repulsion. For example, after the ionic liquid and the graphene oxide dispersion are mixed in a predetermined mass ratio, intercalation exfoliation is achieved by magnetic stirring and heat treatment. It is understandable that the fluidity of the ionic liquid during magnetic stirring can promote the uniformity of the intercalation reaction, while the heating treatment (for example, 60-70°C) can reduce the viscosity of the system to accelerate mass transfer. It should be noted that the reduced pressure dehydration process is used to remove free water in the mixed system to prevent water volatilization during the subsequent curing process from causing pore defects in the coating, and the moisture content after dehydration needs to be controlled below a predetermined threshold.

[0094] As an option, the self-healing polyurethane prepolymer uses dynamic disulfide bonds as self-healing functional units. Specifically, disulfide bonds (-SS-) are introduced into the molecular chain of the prepolymer, which can achieve dynamic breakage and recombination through thiol-disulfide exchange reactions. In one possible implementation, the molecular weight range of the prepolymer is adapted to the rheological properties of the conductive colloid. For example, when the molecular weight is 3000-5000Da, both coating flexibility and dynamic bond mobility can be taken into account. It should be noted that after the prepolymer is heated to the softening point (for example, 60-70°C) and blended with the graphene oxide / ionic liquid system, an interpenetrating network structure can be formed under the action of shear force, in which the distribution density of the dynamic bonds is related to the shear rate and mixing time.

[0095] Exemplarily, fluorosilicone modified nano-silica is surface treated with a silane coupling agent to achieve hydrophobic functionalization. Specifically, the hydrolyzate of the silane coupling agent (e.g., KH-570) reacts with the hydroxyl groups on the surface of the nano-silica to form chemically bonded fluorosilicone segments. In one possible implementation, the mass ratio of the silane coupling agent to the nano-silica is controlled to be 1:10 to 1:15 to ensure a balance between the coverage of the surface modification and the hydrophobic properties. It should be noted that adding nano-silica in batches can avoid uneven dispersion caused by particle agglomeration. For example, three batches are added at intervals, combined with a shear mixing process (e.g., 1000-1500s -1 The uniform dispersion of nanoparticles was achieved by shearing rate.

[0096] It is understood that the component design of conductive colloids achieves functional synergy through the following mechanisms:

[0097] Conductive network construction: Ionic liquid intercalation exfoliates graphene oxide sheets to form three-dimensional interconnected conductive paths; microwave reduction process further restores the conjugated structure of graphene and improves carrier mobility.

[0098] Self-repairing ability: dynamic disulfide bonds undergo reversible breakage and recombination under thermal or mechanical stimulation, repairing microcracks in the conductive network and avoiding shielding effectiveness degradation caused by stress concentration.

[0099] Balance of hydrophobicity and breathability: Fluorosilicone-modified nano-silica constructs a micro-nano rough structure, combined with vapor-deposited fluorine-containing silicon compounds for directional encapsulation to form a low surface energy barrier while retaining breathable channels between base fabric fibers.

[0100] In this embodiment, the plasma activation process enhances the interfacial bonding between the polyester fiber base fabric and the conductive layer through high-energy particle bombardment and surface chemical modification. Specifically, the activation treatment aims to address the issues of insufficient bonding between the coating and the base fabric due to interfacial inertness and easy delamination under dynamic deformation in traditional processes.

[0101] Alternatively, the base fabric may be subjected to a solvent clean prior to plasma treatment to remove surface contaminants. For example, a polyester fiber base fabric is immersed in an acetone solution and ultrasonically assisted to remove residual release agent, grease, and dust from the surface. It should be noted that the polarity of acetone effectively dissolves non-polar organic contaminants, while ultrasonic cavitation accelerates the detachment of contaminants from the fiber surface. It is understood that the cleaned base fabric must be dried to remove any residual solvent and prevent solvent volatilization from interfering with the reaction atmosphere during plasma treatment.

[0102] In one possible implementation, plasma treatment uses radio frequency glow discharge technology to generate oxygen active species. Specifically, the base is placed in a vacuum chamber, high-purity oxygen is introduced as a reactive gas, and ionized by a radio frequency electric field to produce oxygen ions (O+), oxygen free radicals (O*), and high-energy electrons. It should be noted that the chemical activity of oxygen free radicals can trigger the following reactions:

[0103] Surface etching: High-energy particles bombard the polyester fiber surface, selectively etching the amorphous area and increasing the surface roughness (for example, the surface roughness Ra increased from 10nm to 50nm as observed by atomic force microscopy);

[0104] Chemical functionalization: Oxygen free radicals react with benzene rings or ester groups in the polyester molecular chain to generate polar functional groups such as carboxyl (-COOH) and hydroxyl (-OH) (for example, the O / C atomic ratio is detected to increase from 0.25 to 0.35 by X-ray photoelectron spectroscopy).

[0105] Exemplarily, the RF power, gas flow rate and treatment time are adapted to the base fabric material and the target activation degree. Preferably, the RF power range can be set to 50-80W to ensure sufficient ion energy but avoid excessive etching resulting in a decrease in fiber strength. It is understandable that controlling the oxygen flow rate to 20-30sccm can maintain a stable plasma density, and adjusting the chamber pressure (e.g., 50-100Pa) can optimize the mean free path of the active particles, thereby balancing the etching efficiency and uniformity. It should be noted that the treatment time needs to be adjusted according to the thickness of the base fabric. For example, for a base fabric with a thickness of 0.2-0.3mm, a treatment of 3-5 minutes can achieve a surface activation depth of about 50-100nm.

[0106] As an option, the treated base fabric needs to be transferred to the next process within a limited time to maintain surface activity. Specifically, the polar functional groups generated by plasma treatment will gradually be inactivated in the air due to physical adsorption of water molecules or pollutants. Exemplarily, under the condition of ambient humidity ≤60% RH, the half-life of the active sites on the surface of the base fabric is about 3-5 minutes. It is understandable that transferring the treated base fabric to the electrostatic spraying station within ≤30 seconds can make the polyurethane prepolymer amino group (-NH2) in the conductive colloid bond with the carboxyl group on the surface of the base fabric through hydrogen bonds and covalent bonds to form a strong interface anchor. It should be noted that the formation of interfacial chemical bonds can effectively inhibit the tendency of the coating to peel off under dynamic deformation such as bending and stretching.

[0107] It should be noted that the plasma activation process forms a synergistic effect with the subsequent electrostatic spraying and microwave curing steps:

[0108] Improved surface roughness: The micron-scale grooves formed by etching can increase the mechanical bite effect between the conductive colloid and the base fabric;

[0109] Chemical bonding enhancement: Polar functional groups and reactive groups (such as amino and epoxy groups) of polyurethane prepolymers form a covalent bond network to improve interfacial bonding strength;

[0110] Dynamic durability guarantee: Strengthen the interface bonding strength and the self-healing function of the conductive layer to prevent the conductive network from breaking due to interface peeling.

[0111] In this embodiment, the electrostatic spraying process achieves uniform deposition of the conductive colloid on the surface of the fabric and the construction of a functionally graded structure by means of an electric field drive and controlled atomization parameters. Specifically, this process aims to overcome the uneven coating thickness and conductive network breakage caused by gravity sag or capillary action in traditional coating methods, while also adapting to the rheological properties of the self-healing polyurethane prepolymer and the dispersion requirements of the nanoparticles.

[0112] As an option, the electrostatic spraying equipment controls the motion trajectory of the conductive colloid droplets by a high-voltage electrostatic field. Exemplarily, a 40-60kV DC voltage is applied between the nozzle and the base cloth so that the surface of the atomized droplets carries an electric charge (e.g., a positive charge), and the grounded base cloth surface forms an anti-phase electric field. It should be noted that the electric field force can offset the falling effect of gravity on the droplets, so that the droplets are oriented along the electric field lines and adsorbed to the base cloth surface, thereby reducing the coating accumulation in the edge area or insufficient coverage in the center area. It is understandable that the adjustment of the spraying voltage needs to adapt the conductivity of the colloid and the atomized particle size. For example, for ionic liquid-based colloids with higher conductivity, the voltage can be appropriately reduced to avoid the secondary charging of the droplets caused by corona discharge.

[0113] In one possible implementation, the setting of the atomization pressure and the nozzle spacing is used to optimize the droplet size distribution and deposition density. Specifically, the atomization pressure is controlled to 0.3-0.5MPa, and the colloid is broken into droplets of 10-30μm to ensure the balance of fusion and porosity between the droplets during monolayer deposition. It should be noted that too high an atomization pressure may cause the droplets to be too small (for example, <5μm), which is easily affected by airflow disturbances and affects the deposition accuracy; while too low a pressure may cause the droplets to be too large (for example, >50μm), causing sagging or drying shrinkage cracks. Preferably, the distance between the nozzle and the base cloth is set to 15-25cm to balance the electric field strength and the flight time of the atomized droplets, avoiding the "Faraday cage" effect (too thick coating in the edge area) caused by too close a distance or premature drying of the droplets caused by too far a distance.

[0114] Exemplarily, the wet film thickness of the conductive colloid is controlled to be 50-80 μm by the spraying amount. It should be noted that the wet film thickness needs to take into account the density and flexibility of the conductive layer after curing: too thin (for example, <30 μm) may cause discontinuity of the conductive network, while too thick (for example, >100 μm) is prone to cracking due to internal stress concentration. It is understandable that after spraying, standing for leveling for 1-3 minutes (ambient humidity ≤ 40% RH) can allow the droplets to fully merge and expel bubbles, while using gravity to cause the nano-silica particles to settle to the bottom of the coating, forming a gradient structure that is hydrophobic at the bottom and conductive at the top. Preferably, surface defects can be further eliminated by fine-tuning the base fabric level or assisting with vibration during the leveling process.

[0115] As an option, the fluorine-silicon modified nano-silica in the conductive colloid is enriched to the bottom of the coating during the leveling stage due to density differences. Specifically, the nanoparticles (density of about 2.2g / cm 3 ) in a colloidal medium (density about 1.1-1.3 g / cm 3 ) gradually sinks under the action of gravity, while the graphene oxide sheet (density of about 1.8g / cm 3 ) remains suspended due to the intercalation and exfoliation effect of the ionic liquid. It should be noted that the gradient distribution results in a micro-nano rough structure (created by stacked nanoparticles) at the bottom of the cured conductive layer, while retaining a continuous graphene oxide conductive network on the surface, thereby achieving a spatial separation between low surface energy and high conductivity during the subsequent deposition of the hydrophobic layer.

[0116] It should be noted that the electrostatic spraying process parameters (such as voltage, atomization pressure, and spraying amount) need to match the rheological properties of the conductive colloid (such as viscosity and thixotropy). For example, for colloids with higher viscosity (such as 2500-3000mPa·s), the atomization pressure can be appropriately increased to reduce the droplet size, or the spraying voltage can be increased to enhance the electric field driving force. It is understandable that during the spraying process, the wet film uniformity can be monitored in real time through online thickness detection (such as a laser thickness gauge), and the process parameters can be dynamically adjusted based on feedback to ensure that the coating thickness deviation is controlled within ±5%.

[0117] In this embodiment, the microwave reduction and cross-linking curing process simultaneously achieves the reduction of graphene oxide, cross-linking of the conductive network, and activation of the coating's self-healing properties through selective heating and dynamic bond reorganization. Specifically, this process aims to address the low efficiency, high energy consumption, and difficulty in directional activation of dynamic bonds associated with traditional thermal curing, while also adapting to the thermal stability limitations of flexible substrates.

[0118] As an option, microwave treatment uses the dielectric loss characteristics of ionic liquids to achieve local heating. Exemplarily, the sprayed substrate is placed in a microwave reaction chamber, and an inert gas (such as nitrogen or argon) is introduced to suppress the oxidation reaction. It should be noted that the microwave frequency is set to 2.45GHz±50MHz, which is adapted to the dielectric constant (ε'≈12-15) and loss factor (ε"≈5-8) of the ionic liquid, thereby generating local hot spots inside the coating. It is understandable that the polar ion pairs in the ionic liquid (such as [EMIM][TFSI]) are oriented and polarized under the alternating electric field, and the microwave energy is converted into thermal energy through molecular friction, which promotes the volatilization and partial reduction of the intercalant between the graphene oxide sheets.

[0119] In one possible implementation, microwave thermal effect promotes the partial removal of oxygen-containing functional groups (such as epoxy and hydroxyl groups) of graphene oxide, restoring sp 2 Conjugated structure. Specifically, the local temperature gradient (e.g., 60-80°C) generated by microwave heating can trigger the following reactions:

[0120] Intercalant volatilization: The ionic liquid partially evaporates under the action of heat, expanding the interlayer spacing of the graphene oxide sheets (the d-spacing measured by X-ray diffraction is reduced from 1.2nm to 0.4nm), forming a three-dimensional network with in-plane conductivity as the main and interlayer hopping conductivity as the auxiliary;

[0121] Partial reduction: The C / O atomic ratio of graphene oxide increases from 2.1 to 4.3 (determined by X-ray photoelectron spectroscopy), and the carrier mobility increases.

[0122] It should be noted that the dynamic disulfide bonds in the self-repairing polyurethane prepolymer undergo a thiol-disulfide exchange reaction under microwave thermal activation. For example, when the coating temperature reaches the dynamic bond activation energy threshold (e.g., 60-70°C), the disulfide bond (-SS-) breaks to form a thiol end group (-SH), which then recombine with the adjacent thiol or disulfide bond to release internal stress and repair microcracks. It is understandable that the rapid heating and cooling characteristics of microwave heating can avoid thermal degradation of the base fabric caused by long-term high temperature, while ensuring sufficient recombination of the dynamic bonds.

[0123] As an option, the microwave power density is controlled at 0.5-0.8 W / cm 2 , the treatment time is 2-4 minutes. Preferably, the power density setting needs to balance the heating efficiency and the thermal stability of the base fabric. For example, for a polyester base fabric with a thickness of 0.2-0.3 mm, the power density is 0.6 W / cm 2 The coating temperature can be kept below 80°C. It should be noted that real-time temperature monitoring is achieved through an infrared thermal imager or fiber optic sensor. When the monitored temperature exceeds the threshold, the microwave power output is automatically adjusted to prevent the base fabric from shrinking or melting.

[0124] Specifically, the introduction of an inert gas (e.g., nitrogen with a purity of ≥99.99%) is used to exclude oxygen and water vapor, preventing over-oxidation of the graphene oxide or irreversible breakage of dynamic bonds. Exemplarily, the chamber vacuum is controlled at 0.05-0.1 MPa to reduce the interference of gas thermal convection on the temperature distribution. It is understood that a vacuum environment can also accelerate the volatilization of the intercalation agent and promote the dense stacking of the graphene oxide sheets.

[0125] In this embodiment, the hydrophobic layer vapor deposition process uses directional adsorption and surface condensation reactions of fluorinated silicon compounds to create a low-surface-energy barrier on the conductive layer's surface, while preserving breathable channels between the base fabric fibers. Specifically, this process aims to address the issues of traditional hydrophobic coatings, such as reduced air permeability due to densification and easy peeling under dynamic deformation, while also forming a synergistic protective mechanism with the conductive layer's self-healing properties.

[0126] As an option, the hydrophobic layer uses hexamethyldisilazane (HMDS) as a deposition monomer. For example, HMDS vapor is introduced into the deposition chamber under vacuum conditions, allowing it to penetrate into the micro-nanopores on the surface of the conductive layer. It should be noted that the silicon-nitrogen bond (Si-N) in the HMDS molecule can undergo a condensation reaction with the silanol (Si-OH) on the surface of the fluorine-silicon-modified nano-silica in the conductive layer. The reaction formula is as follows:

[0127] Si-OH+(CH3)3Si-NH-Si(CH3)3→Si-O-Si(CH3)3+NH3↑;

[0128] It can be understood that the siloxane bonds (Si-O-Si) generated by the reaction anchor the methyl groups (-CH3) and fluorine silicon segments of HMDS to the surface of the conductive layer, forming a vertically arranged low surface energy structure.

[0129] In one possible implementation, the vapor deposition process achieves efficient reaction through the coordinated regulation of vacuum degree, temperature, and vapor concentration. Specifically, the cured substrate is placed in a vacuum chamber, evacuated to 0.05-0.1 MPa, and then HMDS vapor is introduced, with the vapor concentration controlled at 5-10 vol%. It should be noted that the vacuum environment can reduce the probability of collisions between gas molecules and extend the mean free path of HMDS molecules, thereby enhancing their penetration depth into the pores of the conductive layer. Preferably, the chamber temperature is set to 40-60°C to accelerate the condensation reaction rate but avoid thermal deformation of the substrate.

[0130] For example, the fluorine silicon segments (such as -CF3) of the HMDS molecules are driven by the minimization of surface energy during the vacuum adsorption process and spontaneously arrange themselves in an orientation perpendicular to the surface of the base fabric. It should be noted that this orientation arrangement can maximize the reduction of surface energy (for example, contact angle>160°), while cooperating with the nano-silica micro-nano rough structure at the bottom of the conductive layer (formed by the gradient sedimentation of step three) to construct the Cassie-Baxter hydrophobic state. It can be understood that the micro-nano rough structure reduces the solid-liquid contact area by trapping the air layer, and the low surface energy segments further inhibit the spreading of water droplets, thereby achieving superhydrophobic properties.

[0131] Alternatively, after deposition, physically adsorbed HMDS monomer can be removed by purging with high-pressure nitrogen. Specifically, the nitrogen purge pressure is controlled at 0.2-0.4 MPa, and the purge time is 5-10 seconds. It should be noted that if unreacted HMDS monomer remains on the coating surface, it may be slowly released during subsequent use and affect hydrophobic stability. The purge process effectively removes these free molecules. Preferably, the purge airflow is directed at a 45-60° angle to the substrate surface to enhance the release effect while avoiding damage to the deposited layer.

[0132] Example 1: High conductivity optimization example

[0133] Recipe parameters

[0134] Conductive layer composition:

[0135] Graphene oxide (GO): 14 parts;

[0136] Ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate, [BMIM][PF6]): 38 parts;

[0137] Self-repairing polyurethane prepolymer (containing dynamic disulfide bonds, molecular weight 4500Da): 42 parts;

[0138] Fluorosilicon modified nano-SiO2 (KH-550 grafting rate 88%): 6 parts.

[0139] Process parameters:

[0140] Step 1 (Preparation of conductive colloid):

[0141] Ultrasonic dispersion: GO was ultrasonically treated in deionized water for 50 min (power 450 W, frequency 40 kHz) with a solid content of 2.5 wt%;

[0142] Ionic liquid intercalation: GO dispersion was mixed with [BMIM][PF6] at a ratio of 3.2:1 and magnetically stirred for 3.5 h (temperature 65 °C, rotation speed 1100 rpm) and dehydrated to a water content of 0.4 wt%;

[0143] Prepolymer blending: prepolymer heated to 68 ° C, shear rate 1400s -1 Blend for 18 minutes;

[0144] Nano-SiO2 addition: Add in 4 batches (2.5 minutes interval), total mixing time 8 minutes.

[0145] Step 2 (Plasma Activation):

[0146] Oxygen plasma treatment: power 70 W, time 4.5 minutes, oxygen flow rate 25 sccm, transfer within 28 seconds after treatment.

[0147] Step 3 (electrostatic spraying):

[0148] The spraying voltage was 55 kV, the atomizing pressure was 0.45 MPa, the wet film thickness was 70 μm, and the leveling time was 2.5 minutes (humidity 35% RH).

[0149] Step 4 (microwave curing):

[0150] Microwave frequency 2.45 GHz, power density 0.75 W / cm 2 , treated for 3.5 minutes, peak temperature 78°C (argon protection, vacuum degree 0.07MPa).

[0151] Step 5 (hydrophobic treatment):

[0152] The HMDS vapor concentration was 7 vol%, the treatment time was 10 seconds (temperature 55° C., vacuum degree 0.09 MPa), and the nitrogen purge pressure was 0.35 MPa.

[0153] Example 2:

[0154] Recipe parameters:

[0155] Conductive layer composition:

[0156] Graphene oxide (GO): 11 parts;

[0157] Ionic liquid (1-hexyl-3-methylimidazolium tetrafluoroborate, [HMIM][BF4]): 32 parts;

[0158] Self-repairing polyurethane prepolymer (containing dynamic disulfide bonds, molecular weight 3500Da): 50 parts;

[0159] Fluorosilicon modified nano-SiO2 (KH-792 grafting rate 92%): 7 parts.

[0160] Process parameters:

[0161] Step 1 (Preparation of conductive colloid):

[0162] Ultrasonic dispersion: GO was ultrasonically treated for 35 min (power 350 W), with a solid content of 1.8 wt%;

[0163] Ionic liquid intercalation: GO and [HMIM][BF4] were mixed at a ratio of 3.8:1, stirred for 2 h (temperature 62°C, rotation speed 900 rpm), and dehydrated to a water content of 0.2 wt%;

[0164] Prepolymer blending: shear rate 1300s -1 Blending for 12 minutes (prepolymer temperature 63°C);

[0165] Nano-SiO2 addition: Add in 3 batches (3 minutes interval), total mixing time 7 minutes.

[0166] Step 2 (Plasma Activation):

[0167] Oxygen plasma treatment: power 55 W, time 3.2 minutes, oxygen flow rate 22 sccm, transfer time ≤ 25 seconds.

[0168] Step 3 (electrostatic spraying):

[0169] The spraying voltage was 45 kV, the atomization pressure was 0.35 MPa, the wet film thickness was 55 μm, and the leveling time was 1.5 minutes (humidity 25% RH).

[0170] Step 4 (microwave curing):

[0171] Microwave power density 0.55W / cm 2 , treated for 2.2 minutes, peak temperature 72°C (nitrogen protection, vacuum degree 0.06MPa).

[0172] Step 5 (hydrophobic treatment):

[0173] The HMDS vapor concentration was 9 vol%, the treatment time was 9 seconds (temperature 45° C.), and the purge pressure was 0.25 MPa.

[0174] Example 3:

[0175] Recipe parameters:

[0176] Conductive layer composition:

[0177] Graphene oxide (GO): 13 parts

[0178] Ionic liquid (1-propyl-3-methylimidazolium dicyanamide, [PMIM][DCA]): 36 parts;

[0179] Self-repairing polyurethane prepolymer (containing dynamic disulfide bonds, molecular weight 4800Da): 44 parts;

[0180] Fluorosilicon modified nano-SiO2 (KH-570 grafting rate 95%): 8 parts.

[0181] Process parameters:

[0182] Step 1 (Preparation of conductive colloid):

[0183] Ultrasonic dispersion: GO was ultrasonically treated for 55 min (power 480 W), with a solid content of 2.8 wt%;

[0184] Ionic liquid intercalation: GO and [PMIM][DCA] were mixed at a ratio of 3.6:1 and stirred for 4 h (temperature 68°C, rotation speed 1200 rpm) and dehydrated to a water content of 0.45 wt%;

[0185] Prepolymer blending: shear rate 1450s -1 Blending for 20 minutes (prepolymer temperature 67°C);

[0186] Nano-SiO2 addition: Add in 5 batches (2 minutes interval), total mixing time 9 minutes.

[0187] Step 2 (Plasma Activation):

[0188] Oxygen plasma treatment: power 75 W, time 4.8 minutes, oxygen flow rate 28 sccm, transfer time ≤ 28 seconds.

[0189] Step 3 (electrostatic spraying):

[0190] The spraying voltage was 58 kV, the atomization pressure was 0.48 MPa, the wet film thickness was 75 μm, and the leveling time was 2.8 minutes (humidity 38% RH).

[0191] Step 4 (microwave curing):

[0192] Microwave power density 0.7W / cm 2 , treated for 3.8 minutes, peak temperature 77°C (argon protection, vacuum degree 0.085MPa).

[0193] Step 5 (hydrophobic treatment):

[0194] The HMDS vapor concentration was 10 vol%, the treatment time was 12 seconds (temperature 58° C., vacuum degree 0.095 MPa), and the purge pressure was 0.38 MPa.

[0195] Comparative Example 1:

[0196] Compared with Example 1, the differences are: the ionic liquid [BMIM][PF6] is replaced by an equal amount of ethanol, and the ionic liquid intercalation step is omitted, and the rest are the same.

[0197] Comparative Example 2:

[0198] Compared with Example 1, the difference is that the microwave curing step is cancelled and replaced with hot air curing (120° C., 30 minutes), and the rest are the same.

[0199] Comparative Example 3:

[0200] Compared with Example 2, the difference is that the self-repairing polyurethane prepolymer is replaced by ordinary polyurethane (not containing dynamic disulfide bonds), and the rest are the same.

[0201] Comparative Example 4:

[0202] Compared with Example 2, the difference is that the oxygen plasma activation step is omitted and the untreated base fabric is directly sprayed, and the rest are the same.

[0203] Comparative Example 5:

[0204] Compared with Example 3, the difference is that the fluorine-silicon modified nano-SiO2 is removed (added amount is 0 parts), and the rest are the same.

[0205] Comparative Example 6:

[0206] Compared with Example 3, the difference is that the vacuum deposition hydrophobic treatment step is eliminated and HMDS solution dip coating (drying at room temperature) is used instead, and the rest are the same.

[0207] Experiment 1: Conductive Network Construction Effectiveness Test Instructions

[0208] Experimental purpose: To verify the necessity of ionic liquid intercalation and microwave reduction process for the formation of conductive network.

[0209] Experimental steps:

[0210] Sample preparation:

[0211] Example 1: Three groups of samples (numbered S1-1 to S1-3) were prepared according to the formulation and process of Example 1;

[0212] Comparative Example 1: The ionic liquid was replaced with ethanol to prepare three groups of samples (numbered C1-1 to C1-3);

[0213] Comparative Example 2: Microwave curing was eliminated and hot air curing (120°C / 30 minutes) was adopted to prepare three groups of samples (numbered C2-1 to C2-3).

[0214] Resistivity test:

[0215] The surface resistivity of each sample was measured three times using a four-probe tester (model: RTS-9) at 25° C. / 60% RH, and the average value was taken.

[0216] Shielding effectiveness test:

[0217] The electromagnetic shielding effectiveness was tested using a vector network analyzer (Keysight N5224B) at a frequency of 1 GHz according to ASTM D4935.

[0218] Oxygen content analysis:

[0219] X-ray photoelectron spectroscopy (XPS, model: Thermo Scientific K-Alpha) was used to detect the oxygen-carbon ratio (O / C) of the coating surface.

[0220] Table 1 Test Example 1 Experimental Data Table: Conductive Network Performance Comparison

[0221] Sample number Surface resistivity (Ω·cm) Shielding effectiveness (dB) XPS oxygen content (O / C) Example 1 S1-1 27.3 57.8 0.09 S1-2 29.1 56.2 0.11 S1-3 31.5 55.4 0.08 Comparative Example 1 C1-1 502.6 17.3 0.32 C1-2 489.2 15.8 0.35 C1-3 -(Coating peeling off) - - Comparative Example 2 C2-1 148.7 39.1 0.24 C2-2 162.3 37.6 0.27 C2-3 155.9 41.2 0.22

[0222] According to Table 1 above, we can see that:

[0223] This experiment verified the synergistic mechanism of ionic liquid intercalation and microwave selective reduction on the construction of conductive network by comparing the difference in conductive properties between Example 1 and Comparative Examples 1-2. In Example 1, the ionic liquid [BMIM][PF6] is thermally driven to penetrate into the interlayer of graphene oxide (GO), and its cations interact with the π-π interaction and hydrogen bonds of the GO sheets, expanding the interlayer spacing from the original 0.34nm to 0.9-1.1nm, forming a continuous three-dimensional conductive skeleton. At the same time, microwave radiation (2.45GHz) preferentially breaks the CO bond rather than the CC bond by targeted excitation of the molecular vibration energy of GO oxygen-containing groups (such as epoxy groups), reducing the oxygen content from the initial 32wt% to 8-11wt%, significantly improving the electron mobility of reduced graphene (rGO). This "intercalation expansion-directional reduction" dual-path mechanism makes Example 1 far superior to conventional solutions in resistivity (28Ω·cm) and shielding effectiveness (57dB).

[0224] The failure of Comparative Example 1 (resistivity > 500 Ω·cm) directly demonstrates the irreplaceable nature of ionic liquid intercalation: ethanol, lacking polar functional groups and interlayer forces, is unable to untie the GO stacking structure, leading to sheet agglomeration (average agglomerate size > 5 μm as measured by SEM) and disrupted electron transport. In Comparative Example 2, hot air curing, which uniformly applied heat to the entire coating, not only failed to selectively reduce GO (residual oxygen > 22 wt%) but also triggered thermal degradation of the polyurethane prepolymer (TGA showed a 12% increase in weight loss), reducing the efficiency of dynamic disulfide bond recombination and further exacerbating conductive network defects.

[0225] The matching of experimental data with theoretical models demonstrates that the novelty of this invention lies in resolving the contradiction between conductivity and stability through a coupled component-process approach: ionic liquid intercalation ensures the topological connectivity of the conductive network, while the localized energy input of microwaves achieves efficient GO reduction while avoiding thermal damage. This precise control results in a resistivity increase of only 9% in the conductive layer after aging for 1000 hours at 85°C / 85% RH, breaking through the environmental tolerance bottleneck of traditional flexible shielding materials.

[0226] Experiment 2: Comprehensive test description of self-repair and interface combination

[0227] Experimental purpose: To verify the synergistic effect of dynamic disulfide bond self-repairing network and plasma activation on interfacial binding force.

[0228] Experimental steps:

[0229] Sample preparation:

[0230] Example 2: Three groups of samples (numbered S2-1 to S2-3) were prepared according to the formulation and process of Example 2;

[0231] Comparative Example 3: The self-healing polyurethane was replaced with ordinary polyurethane (without dynamic bonds) to prepare three groups of samples (numbered C3-1 to C3-3);

[0232] Comparative Example 4: The plasma activation step was omitted, and three groups of samples (numbered C4-1 to C4-3) were prepared.

[0233] Scratch repair test:

[0234] A 50 μm wide scratch was made on the coating surface using a diamond probe (load 10 N) and then repaired by heating at 60 °C;

[0235] The repair efficiency was measured by laser confocal microscopy (Olympus LEXT OLS5000).

[0236] Peel strength test:

[0237] The 180° peeling method (ASTM D903) was used with a tensile rate of 50 mm / min, and the maximum peeling force was recorded.

[0238] Porosity analysis:

[0239] The coating cross section was observed using SEM (model: Hitachi SU8010), and the pore area ratio was calculated using ImageJ software.

[0240] Table 2 Experimental data of test case 2: comparison of self-repair and interface performance

[0241] Sample number Repair rate (%) Peel strength (N / cm) Porosity (%) Example 2 S2-1 96.5 3.2 1.8 S2-2 98.2 2.9 2.1 S2-3 94.3 3.4 3.0 (local bubbles) Comparative Example 3 C3-1 0 (not repaired) 1.5 4.7 C3-2 0 (not repaired) 1.3 5.2 C3-3 -(Coating brittle cracking) - 6.8 Comparative Example 4 C4-1 81.4 0.7 8.3 C4-2 79.6 0.9 7.5 C4-3 83.1 0.6 9

[0242] According to Table 2 above, we can see that:

[0243] This experiment reveals the synergistic mechanism of the dynamic disulfide network and plasma activation process by comparing the difference in self-repair performance and interfacial binding strength. In Example 2, the dynamic disulfide bond (-SS-) undergoes a thiol-disulfide exchange reaction when heated at 60°C (FTIR detected at 510 cm -1 The SS stretching vibration peak intensity at the base fabric decreased by 42%, prompting the rearrangement of polymer chain segments and achieving a scratch repair rate of >94%. At the same time, oxygen plasma treatment generates hydroxyl (-OH) and carboxyl (-COOH) groups on the surface of the base fabric, forming covalent urethane bonds with the isocyanate (-NCO) groups of the polyurethane prepolymer (XPS shows N1s binding energy of 399.8eV). The interfacial peel strength reaches 3.2N / cm, which is 4 times higher than traditional physical adsorption (van der Waals force). This "dynamic network reconstruction-chemical bonding" dual-path mechanism allows the material to maintain a complete conductive path after repeated bending (curvature radius of 2mm).

[0244] The complete failure (0% repair rate) of Comparative Example 3 demonstrates the crucial role of dynamic bonds: the permanently cross-linked network of conventional polyurethane cannot release internal stress through bond reorganization, resulting in a crack tip stress concentration factor (Kt) as high as 3.8 (FEA simulation results), leading to brittle fracture. In contrast, the unactivated base fabric of Comparative Example 4 has a surface energy of only 28 mN / m (contact angle 85°), and the coating relies solely on weak interfacial bonding. Cohesive failure occurs during peeling (SEM reveals a smooth fracture surface with no fiber attachment), and the porosity increases to 8.3% (from 1.8%), further reducing electromagnetic shielding effectiveness.

[0245] Experimental data and molecular dynamics (MD) simulations demonstrate that the novelty of this invention lies in resolving the conflict between mechanical durability and signal stability in flexible electronic devices by coupling dynamic bond topology reconstruction with interfacial chemical anchoring. This dynamic network maintains a resistance fluctuation of less than 5% after 100,000 bends, while plasma activation ensures interfacial stability (peel strength decay of less than 8%) in extreme humidity (95% RH), providing theoretical and technical support for the long-term reliable operation of wearable devices.

[0246] Experiment 3: Superhydrophobicity and Environmental Tolerance Test Instructions

[0247] Experimental purpose: To verify the synergistic effect of nano-SiO2 roughness and vapor deposition process on superhydrophobicity and durability.

[0248] Experimental steps:

[0249] Sample preparation:

[0250] Example 3: Three groups of samples (numbered S3-1 to S3-3) were prepared according to the formulation and process of Example 3;

[0251] Comparative Example 5: 3 groups of samples (numbered C5-1 to C5-3) were prepared by removing the fluorine-silicon modified nano-SiO2 (addition amount 0);

[0252] Comparative Example 6: The vacuum deposition process was eliminated and HMDS solution dip coating (room temperature drying) was used instead to prepare three groups of samples (numbered C6-1 to C6-3).

[0253] Hydrophobicity test:

[0254] A contact angle meter (model: OCA20, water drop volume 5 μL) was used to measure the static contact angle and rolling angle;

[0255] Water impact test: Deionized water was sprayed at a flow rate of 10 mL / s, and the time it took for the contact angle to decay to 120° was recorded.

[0256] Air permeability test:

[0257] According to ISO 9237, air permeability was measured using an air permeability meter (model: FX3300) (pressure difference 100 Pa).

[0258] Corrosion resistance test:

[0259] Salt spray test (5% NaCl solution, 35°C), record the time when the coating shows corrosion spots or peeling.

[0260] Table 3 Experimental data table of Test Example 3: Comparison of superhydrophobic performance and durability.

[0261]

[0262]

[0263] According to Table 3 above, we can see that:

[0264] This experiment reveals the synergistic mechanism of nano-SiO2 micro-nano rough structure and vapor deposition process through super hydrophobic performance and durability tests. In Example 3, fluorosilicon modified nano-SiO2 (contact angle 163°) forms a multi-level concave-convex structure on the fiber surface by electrostatic adsorption (SEM shows Ra = 1.8μm), combined with vacuum deposited hexamethyldisilazane (HMDS) for directional arrangement, and constructs a chemically inert layer in the fiber pores (XPS shows that Si-O-Si bonds account for 68%), so that the water droplets are in the Cassie-Baxter state (rolling angle <5°). The negative pressure environment (10Pa) of vapor deposition forces HMDS to cross-link deeply into the fiber to form a dense and breathable hydrophobic barrier (air permeability > 300L / m 2 ·s), and no chloride ion penetration was observed after 240 hours of salt spray corrosion (EDS detected Cl content < 0.1wt%).

[0265] The failure of Comparative Example 5 (contact angle <130°) proves that single chemical modification cannot achieve superhydrophobicity: the smooth surface without nano-SiO2 (Ra = 0.2μm) relies solely on fluorosilane to reduce the surface energy. The water droplets fall into the Wenzel state (rolling angle > 28°) due to capillary force, and Cl- in salt spray quickly erodes the interface through defects (Cl content 0.8wt%). The dip coating process of Comparative Example 6 blocks the pores of the base fabric (air permeability <90L / m 2 ·s), the disordered stacked HMDS layer (AFM shows a film thickness fluctuation of ±30nm) hydrolyzes under humidity (FTIR detects a 60% decrease in the Si-O-Si peak intensity), and the contact angle decays to below 100° within 24 hours, losing its protective function.

[0266] Experimental data agrees well with a modified Young-Laplace equation model, demonstrating that the superhydrophobicity of the present invention stems from a dual mechanism of "micro-nano water retention and chemical passivation": nano-SiO2 provides mechanical support against compression, while vapor deposition enables molecular-level directional encapsulation. These two mechanisms work together to maintain a contact angle >155° in extreme environments (-20°C ice crystal friction and 50°C sweat immersion). This resolves the conflict between mechanical strength and breathability inherent in traditional hydrophobic coatings, providing a new paradigm for flexible electronic packaging in harsh environments.

[0267] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An electromagnetic shielding equipotential cover cloth, characterized in that: include: Polyester fiber base fabric layer (1); A conductive layer (2) coated on the surface of a base fabric, wherein the conductive layer (2) is composed of the following components in parts by mass: 10-15 parts of graphene oxide; 30-40 parts of ionic liquid; 40-50 parts of self-repairing polyurethane prepolymer; 5-8 parts of fluorine-silicon modified nano-silicon dioxide; A hydrophobic layer (3) covers the surface of the conductive layer (2), wherein the hydrophobic layer (3) is formed by vapor deposition of a fluorine-containing silicon compound.

2. The electromagnetic shielding equipotential cover cloth according to claim 1, characterized in that: The ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt.

3. The electromagnetic shielding equipotential cover cloth according to claim 1, characterized in that: The surface of the fluorine-silicon modified nano-silica is treated with a silane coupling agent, and the mass ratio of the silane coupling agent to the nano-silica is 1:10 to 1:

15.

4. The electromagnetic shielding equipotential cover cloth according to claim 1, characterized in that: The self-repairing polyurethane prepolymer contains dynamic disulfide bonds and has a molecular weight of 3000-5000 Da.

5. A production process for an electromagnetic shielding equipotential cover cloth, according to the electromagnetic shielding equipotential cover cloth according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: mixing graphene oxide, ionic liquid, self-healing polymer and nano-modifier to prepare a conductive colloid; Step 2: Plasma activation treatment of the polyester fiber base fabric; Step 3: Applying the conductive colloid to the surface of the activated base fabric through an electrostatic spraying process; Step 4: using microwave radiation to reduce and crosslink the coating; Step 5: Perform hydrophobic strengthening treatment on the cured coating surface.

6. The production process of the electromagnetic shielding equipotential cover cloth according to claim 5, characterized in that: The step 1 includes the following processing: Dispersing graphene oxide in deionized water and ultrasonically treating for 30-60 minutes to obtain a dispersion with a solid content of 1-3 wt%; The ionic liquid and the graphene oxide dispersion are mixed in a mass ratio of 3:1 to 4:1, magnetically stirred for 2 to 4 hours at a temperature of 60-70° C., and dehydrated under reduced pressure to a water content of ≤0.5 wt %; Heat the self-repairing polyurethane prepolymer to 60-70°C and blend it with the mixture at a shear rate of 1000-1500s -1 , time 10-20 minutes; Add fluorine-silicon modified nano-silica and mix in batches, with an interval of 2 to 3 minutes between each addition, and a total mixing time of 5-10 minutes.

7. The production process of the electromagnetic shielding equipotential cover cloth according to claim 5, characterized in that: The second step includes: The polyester fiber substrate is placed in an oxygen plasma treatment chamber, and oxygen gas with a purity of ≥99.99% is introduced at a gas flow rate of 20 to 30 sccm; Start the RF power supply, control the power to 50 to 80 W, the processing time to 3 to 5 minutes, and the chamber pressure to 50 to 100 Pa; The treated base fabric is transferred to the electrostatic spraying station for step three within ≤30 seconds.

8. The production process of the electromagnetic shielding equipotential cover cloth according to claim 5, characterized in that: The step three includes: Adjust the parameters of the electrostatic spraying equipment: spraying voltage 40-60kV, atomization pressure 0.3-0.5MPa, and the distance between the nozzle and the base fabric 15-25cm; Control the amount of conductive colloid sprayed to make the wet film thickness 50-80μm; After spraying, let it stand for 1-3 minutes to level. The ambient humidity should be ≤40% RH.

9. The production process of the electromagnetic shielding equipotential cover cloth according to claim 5, characterized in that: The fourth step includes: Place the sprayed substrate in a microwave reaction chamber, introduce inert gas nitrogen or argon with a gas purity of ≥99.99% and a chamber vacuum of 0.05-0.1 MPa; Start microwave radiation, control the frequency to 2.45GHz±50MHz, and the power density to 0.5-0.8W / cm 2 , processing time 2-4 minutes; Simultaneously monitor the coating temperature and control the peak temperature to ≤80℃.

10. The production process of the electromagnetic shielding equipotential cover cloth according to claim 5, characterized in that: The step five includes: The cured substrate is placed in a vacuum deposition chamber and hexamethyldisilazane vapor is introduced at a vapor concentration of 5-10 vol%; The chamber temperature is controlled at 40-60°C, the vacuum degree is 0.05-0.1 MPa, and the processing time is 8-12 seconds; After the treatment is completed, nitrogen is purged for 5-10 seconds at a pressure of 0.2-0.4 MPa.

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