High-fineness stretchable flexible fabric circuit and preparation method thereof

Abstract

The invention belongs to the technical field of flexible circuits, and particularly relates to a high-fineness stretchable flexible fabric circuit and a preparation method thereof. The method comprises the steps that liquid metal micro-droplets are prepared through ultrasonic waves, and monomers are connected and modified to the surfaces of the liquid metal micro-droplets through groups such as hydroxyl and sulfydryl; uniformly dispersing the monomer-modified liquid metal micro-droplets, a monomer, a photoinitiator, a cross-linking agent, a diluent and the like in ethanol; treating the photoetched fabric by using oxygen plasma; soaking the fabric subjected to oxygen plasma treatment in liquid metal photoetching slurry, placing the fabric on a photoetching platform, performing double-sided ultraviolet exposure based on a required circuit pattern, and using ethanol and deionized water as developing liquid to obtain a fabric circuit pattern. And sintering the fabric circuit pattern to obtain a conductive path. The stretchable flexible fabric circuit with complex patterns and high precision can be simply and conveniently prepared on various fabrics, and the conductive stability is excellent.

Description

Technical Field

[0001] The present invention belongs to the technical field of intelligent electronic fabrics, and in particular relates to a high-precision stretchable flexible fabric circuit and a preparation method thereof. Background Art

[0002] In recent years, as an important direction for the development of future electronic devices, flexible wearable electronic products have gradually developed towards high integration and multifunctionality, and their application prospects are broad. Among them, electronic fabrics have the advantages of adapting to complex deformations, breathability and moisture conduction, and are considered to be an important development direction in the wearable field. Constructing high-precision, stretchable and highly conductive pathways in electronic fabrics is the key to achieving functional integration and practical applications of electronic fabrics. However, how to achieve high flexibility and breathability of the conductive pathway of the fabric, and how to withstand complex deformations such as bending, twisting and stretching, has always been an important challenge in the field of electronic fabrics.

[0003] At present, fabric circuits are mainly prepared by printing technology and textile technology. Printing technology such as screen printing and inkjet printing can quickly and easily prepare complex circuits, but because the fabric substrate is difficult to spread completely flat during the printing process, and the conductive ink is easy to diffuse along the porous fabric fibers, it is easy to cause low circuit accuracy. Traditional textile technology integrates conductive yarns into fabrics through knitting and embroidery methods. The process is simple, and the prepared fabric circuits can not only retain the flexibility and air permeability of the fabric, but also have good mechanical stability. However, this technology has high requirements on the mechanical strength and flexibility of the conductive yarn, and has poor compatibility with standard electronic manufacturing processes, and it is difficult to achieve complex circuits with high precision. Invention patent CN116261274A discloses a method of using a magnetron sputtering method to plate a metal film on both surfaces of an elastic fabric, and preparing a flexible conductive path on the fabric by photolithography technology. The fabric circuit has good flexibility and water washability. However, this method is only applicable to nylon yarns with good heat resistance, and its application range is limited. The paper "Well-defined in-textile photolithography towards permeable textile electronics" Nature Communications 2024, 15, 887 reported that conductive metal patterns were prepared in fabrics by in-fabric photolithography. The study used copper as the conductive material, which can maintain good conductivity when the fabric undergoes basic deformations such as bending and twisting, but cannot withstand tensile deformation and its application scenarios are also very limited.

[0004] Therefore, it is of great significance to establish a method for constructing high-precision and stretchable textile circuits on a variety of fabrics to meet the requirements of electronic textiles for conductive stability under complex deformation conditions such as stretching, bending, and twisting. Summary of the invention

[0005] The purpose of the present invention is to provide a flexible fabric circuit with high precision and good stretchability and a preparation method thereof, so as to solve the technical problem that traditional printing textile technology is difficult to prepare complex pattern circuits on the fabric surface and cannot meet the complex deformation requirements such as stretching, bending, and twisting.

[0006] The high-definition stretchable flexible fabric circuit provided by the present invention modifies the surface of liquid metal micro-droplets with photocurable monomers, and obtains a slurry that can be applied to fabric photolithography by compounding the modified liquid metal micro-droplets, photocurable monomers, photoinitiators, cross-linking agents, etc.; and prepares high-definition stretchable flexible fabric circuits by double-sided photolithography technology. The specific preparation steps are as follows:

[0007] (1) preparing liquid metal microdroplets modified by photocurable monomers; preparing liquid metal microdroplets in a solvent by an ultrasonic cell crusher, and modifying the monomers on the surface of the liquid metal microdroplets by hydroxyl groups; the liquid metal used is a eutectic gallium-indium alloy; the specific process is as follows:

[0008] (a) 300-600 mg of eutectic gallium-indium alloy and 10-15 mL of anhydrous ethanol are placed in a glass bottle, and the glass bottle is immersed in an ice-water mixture. Then, the probe of an ultrasonic cell pulverizer is inserted into the glass bottle and maintained below the liquid level in the glass bottle, and ultrasonicated until the solution in the glass bottle changes from a clear and transparent state to a light gray state;

[0009] (b) adding 20-40 mg of photocurable monomer 4-hydroxybutyl acrylate (4-HBA) into the glass bottle and continuing ultrasonication until the solution in the glass bottle changes from light gray to dark gray;

[0010] (c) placing the glass bottle in an ultrasonic cleaning apparatus and allowing the hydroxyl groups in the photocurable monomer 4-HBA to fully react with the gallium oxide shell of the liquid metal microdroplets;

[0011] (d) pouring the solution in the glass bottle into a centrifuge tube, centrifuging it in a centrifuge, pouring out the supernatant, and leaving the precipitate; placing the precipitate in the centrifuge tube in a freeze dryer to dry it, thereby obtaining liquid metal microdroplets modified by a photocurable monomer;

[0012] (2) Preparing liquid metal photolithography slurry: uniformly dispersing liquid metal droplets modified with photocurable monomers, photocurable monomers, photoinitiators, crosslinking agents, diluents, etc. in ethanol to obtain liquid metal photolithography slurry; the specific process of preparing the liquid metal photolithography slurry is as follows:

[0013] Add 300-500 mg of the liquid metal microdroplets modified with the photocurable monomer obtained in step (1) and 0.2-0.5 mL of anhydrous ethanol into a light-proof glass bottle (e.g., a brown glass bottle), and place in an ultrasonic cleaner for uniform dispersion;

[0014] Then, 2-5 mmol of photocurable monomer 4-HBA, 0.01-0.03 mmol of photoinitiator, 0.001-0.003 mmol of crosslinker and 30-50 mg of diluent are added in sequence; a magnetic stirrer is placed and stirred on a magnetic stirrer for 12-20 hours to obtain a liquid metal photolithography slurry that can be used for photolithography on fabrics;

[0015] (3) first treating the fabric to be photolithographically processed with oxygen plasma to enhance the adhesion of the liquid metal photolithography slurry on the fabric surface;

[0016] (4) immersing the oxygen plasma-treated fabric in a liquid metal photolithography slurry, taking it out and placing it on a photolithography platform, placing it between two mask plates for double-sided ultraviolet exposure, and using ethanol and deionized water as developer for development to obtain a high-definition, stretchable flexible fabric circuit pattern;

[0017] (5) Sintering the high-definition, stretchable flexible fabric circuit pattern to obtain a conductive path, i.e., a high-definition, stretchable flexible fabric circuit.

[0018] In step (1), the size of the liquid metal micro-droplets modified by the photocurable monomer is 200 to 500 μm.

[0019] In the step (1):

[0020] In step (a), the glass bottle is immersed in the ice-water mixture until the liquid level of the ice-water mixture reaches 1 / 2 to 2 / 3 of the glass bottle; then the probe of the ultrasonic cell pulverizer is kept at the lower 1 / 2 to 2 / 3 of the liquid level in the glass bottle; the ultrasonic power is set to 45% to 70%, and the ultrasonic time is 5 to 10 minutes;

[0021] In step (c), the glass bottle is placed in an ultrasonic cleaner for 15 to 30 hours;

[0022] In step (b), ensure that the liquid level of the ice-water mixture is at 1 / 2 of the glass bottle; then set the ultrasonic power to 45% to 70% and the ultrasonic time to 25 to 40 minutes;

[0023] In step (d), centrifuge at 3000 r / min for 5 to 25 min; and dry in a freeze dryer for 5 to 10 h.

[0024] In the step (2), the photoinitiator is trimethylbenzoyl-diphenylphosphine oxide (TPO), the crosslinking agent is one or more of trimethylolpropane triacrylate (TMPTMA) and polyethylene glycol dimethacrylate (PEGDA), and the diluent is polyethylene glycol (PEG).

[0025] In the step (3), the specific process of treating the fabric to be photoetched with oxygen plasma is as follows:

[0026] The fabric is placed in an oxygen plasma cleaning machine, the vacuum pressure value is set to 900 Pa, the radio frequency power is 100-180 W, and the processing time is 2-10 minutes; the fabric is one of polyester, nylon and cotton.

[0027] In the step (4), the soaking time is 5 to 10 seconds.

[0028] In the step (4), the specific process of performing photolithography on the photolithography platform is as follows:

[0029] The soaked fabric is laid flat on the mask plate and fixed at the four corners, and then another mask plate with the same pattern is placed on it, positioned and fixed through the positioning holes to obtain a fabric and mask plate combination; a photolithography light source is placed on the fabric and mask plate combination, and exposed for 15 to 30 seconds; the fabric and mask plate combination is turned over and exposed again for 15 to 30 seconds;

[0030] The mask is a tungsten sheet, contains a circuit pattern, and is provided with positioning holes; the wavelength of the photolithography light source is 350-390nm;

[0031] After the exposure is completed, the fabric is taken out from the two masks, placed in a glass dish, and poured with developer; the glass dish is placed in an ultrasonic cleaner and treated at room temperature for 30 to 50 seconds; after being taken out, it is naturally air-dried to obtain a high-precision, stretchable flexible fabric circuit pattern.

[0032] In the step (4), the developer is a mixed solution of anhydrous ethanol and deionized water in a volume ratio of 1:1 to 2:1.

[0033] In the step (5), the sintering is mechanical sintering by pressurization and friction. The outer shell of the liquid metal droplets modified by the photocurable monomer is broken during the sintering process, and the internal liquid metal flows out to form a conductive path, and finally a conductive path on the fabric is obtained.

[0034] In the present invention, the stretchable flexible fabric circuit prepared by the above method has a minimum circuit width of 100 μm and a resistance of 5 to 10 Ω, and has good stretchability, flexibility and mechanical stability.

[0035] The advantages of the present invention are:

[0036] The present invention uses liquid metal as the conductive material, which can fully meet the conductive stability of the fabric during common deformation processes such as bending, twisting, and stretching;

[0037] The fabric circuit of the present invention has high fineness, good flexibility, good stretchability, excellent conductive stability and other characteristics, and has important application value in the field of intelligent electronic fabrics;

[0038] The preparation process of the invention is simple, the conditions are mild, and it can be applied to a variety of fabrics and has universal applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Flow chart for the preparation of high-precision stretchable flexible fabric circuits.

[0040] Figure 2 Comparison of liquid metal photolithography materials before and after sintering. The left picture shows the state before sintering, when the photolithography pattern is insulated; the right picture shows the state after sintering, when a conductive path is formed.

[0041] Figure 3 This is an optical microscope image of a highly precise stretchable flexible fabric circuit.

[0042] Figure 4 This is a physical picture of a high-precision stretchable flexible fabric circuit.

[0043] Figure 5 The resistance stability of high-definition stretchable flexible fabric circuits when stretched at different ratios.

[0044] Figure 6 The resistance stability of high-definition stretchable flexible textile circuits during cyclic stretching.

[0045] Figure 7 The resistance stability of high-definition stretchable flexible fabric circuits during cyclic bending. DETAILED DESCRIPTION

[0046] In order to more clearly explain the purpose and technical solutions of the embodiments of the present invention, the technical solutions in the embodiments of the present invention are now described in detail, but it does not mean that the present invention is limited to the specific embodiments. For experimental processes where the conditions are not specifically indicated in the following embodiments, conventional methods and conditions shall prevail, or they shall be carried out according to the selection of the product instructions.

[0047] The reagents used in the following examples were purchased from Shanghai Bid Pharmaceutical Technology Co., Ltd. All the equipment in the following examples are conventional equipment that can be purchased commercially.

[0048] Example 1

[0049] A method for preparing a high-precision stretchable flexible fabric circuit, the specific preparation process is as follows:

[0050] Step 1: Preparation of liquid metal microdroplets modified by photocurable monomers: 300 mg of eutectic gallium-indium alloy and 10 mL of anhydrous ethanol were placed in a 20 mL glass bottle, and the glass bottle was immersed in an ice-water mixture, and the liquid level of the ice-water mixture reached 1 / 2 of the glass bottle. The probe of the ultrasonic cell crusher was inserted into the glass bottle, and the probe was kept at the lower 2 / 3 of the liquid level in the glass bottle. The ultrasonic power was set to 45% and the ultrasonic time was 5 min. After that, 30 mg of photocurable monomer 4-HBA was added to the glass bottle, and the liquid level of the ice-water mixture was ensured to be at 1 / 2 of the glass bottle. The ultrasonic power was set to 55% and the ultrasonic time was 25 min, so that the solution in the glass bottle changed from light gray to dark gray. After placing the glass bottle in an ultrasonic cleaner for 20 hours, the solution was poured into a centrifuge tube, placed in a centrifuge and centrifuged at 3000 r / min for 10 minutes, and the supernatant was poured out. Finally, the precipitate in the centrifuge tube was placed in a freeze dryer and dried for 5 hours to obtain liquid metal microdroplets modified by photocurable monomers.

[0051] Step 2: Prepare liquid metal photolithography slurry: Add 300 mg of liquid metal droplets modified by photocurable monomers and 0.2 mL of anhydrous ethanol to a 2 mL brown glass bottle, keep it away from light, and place it in an ultrasonic cleaner for uniform dispersion. Then add 2 mmol 4-HBA, 0.01 mmol TPO, 0.002 mmol TMPTMA and 30 mg PEG in sequence. Add a magnetic stirrer and stir it on a magnetic stirrer for 12 hours.

[0052] Step 3: Treat the photoetched fabric with oxygen plasma: Place the nylon fabric in an oxygen plasma cleaning machine, set the vacuum pressure value to 900 Pa, the radio frequency power to 150 W, and the treatment time to 5 min.

[0053] Step 4: Photolithography to obtain flexible fabric circuit pattern: Soak the nylon fabric in the photolithography slurry for 5 seconds and lay it flat on the mask, then place another mask with the same pattern on it, position and fix it through the positioning holes to obtain a fabric and mask composite. Place a light source with a wavelength of 390nm on the fabric and mask composite and expose it for 15 seconds; flip the fabric and mask composite and expose it again for 15 seconds. After that, take the fabric out of the two masks, place it in a glass dish, and pour a mixed solution of anhydrous ethanol and deionized water in a volume ratio of 1:1 as a developer. Place the glass dish in an ultrasonic cleaner and treat it at room temperature for 30 seconds. After taking it out, let it air dry naturally to obtain a flexible fabric circuit pattern.

[0054] Step 5: Sintering the flexible fabric circuit pattern: Place the PET sheet on top of the fabric circuit pattern obtained by photolithography, use a metal rod to roll over the PET sheet, apply pressure and shear force to the fabric circuit pattern part, so that the shell of the liquid metal micro-droplet breaks, and the liquid metal inside flows out to form a continuous conductive path.

[0055] Step 6: Apply different strains to the high-precision stretchable flexible fabric circuit to test its stability under different strains. Figure 5 As shown, the resistance change rate of the fabric circuit is less than 1.2% under 50%, 100%, 150%, 200%, and 250% strain. The above test results show that the high-precision stretchable flexible fabric circuit has excellent conductive stability under different degrees of deformation.

[0056] Example 2

[0057] A method for preparing a high-precision stretchable flexible fabric circuit, the specific preparation process is as follows:

[0058] Step 1: Preparation of liquid metal microdroplets modified by photocurable monomers: 450 mg of eutectic gallium-indium alloy and 12 mL of anhydrous ethanol were placed in a 20 mL glass bottle, and the glass bottle was immersed in an ice-water mixture, and the liquid level of the ice-water mixture reached 2 / 3 of the glass bottle. Insert the probe of the ultrasonic cell crusher into the glass bottle, and keep the probe at the lower 1 / 2 of the liquid level in the glass bottle. Set the ultrasonic power to 55% and the ultrasonic time to 10 min. After that, add 20 mg of photocurable monomer 4-HBA to the glass bottle, and ensure that the liquid level of the ice-water mixture is at 2 / 3 of the glass bottle. Set the ultrasonic power to 60% and the ultrasonic time to 25 min, so that the solution in the glass bottle changes from light gray to dark gray. After placing the glass bottle in an ultrasonic cleaner for 24 hours, pour the solution into a centrifuge tube, place it in a centrifuge and centrifuge it at 3000 r / min for 25 minutes, and pour out the supernatant. Finally, the precipitate in the centrifuge tube was placed in a freeze dryer and dried for 10 h to obtain liquid metal microdroplets modified with photocurable monomers.

[0059] Step 2: Prepare liquid metal photolithography slurry: Add 400 mg of liquid metal droplets modified by photocurable monomers and 0.4 mL of anhydrous ethanol to a 2 mL brown glass bottle, keep it away from light, and place it in an ultrasonic cleaner for uniform dispersion. Then add 3 mmol 4-HBA, 0.02 mmol TPO, 0.001 mmol PEGDA and 40 mg PEG in sequence. Add a magnetic stirrer and stir on a magnetic stirrer for 12 hours.

[0060] Step 3: Treat the photoetched fabric with oxygen plasma: Place the polyester fabric in an oxygen plasma cleaning machine, set the vacuum pressure value to 900 Pa, the radio frequency power to 180 W, and the treatment time to 2 min.

[0061] Step 4: Photolithography to obtain flexible fabric circuit pattern: Soak the nylon fabric in the photolithography slurry for 5 seconds and lay it flat on the mask, then place another mask with the same pattern on it, position and fix it through the positioning holes to obtain a fabric and mask composite. Place a light source with a wavelength of 350nm on the fabric and mask composite and expose it for 30 seconds; flip the fabric and mask composite and expose it again for 30 seconds. After that, take the fabric out of the two masks, place it in a glass dish, and pour a mixed solution of anhydrous ethanol and deionized water in a volume ratio of 1:1 as a developer. Place the glass dish in an ultrasonic cleaner and treat it at room temperature for 45 seconds. After taking it out, let it air dry naturally to obtain a flexible fabric circuit pattern.

[0062] Step 5: Sintering the flexible fabric circuit pattern: Place the PET sheet on top of the fabric circuit pattern obtained by photolithography, use a metal rod to roll over the PET sheet, apply pressure and shear force to the fabric circuit pattern part, so that the shell of the liquid metal micro-droplet breaks, and the liquid metal inside flows out to form a continuous conductive path.

[0063] Step 6: The high-precision stretchable flexible fabric circuit is cyclically stretched 30,000 times at 20% strain, and then its resistance value is tested. The results are as follows: Figure 6 As shown, the resistance change rate of the fabric circuit is less than 1.1%, reflecting good cyclic stretching stability.

[0064] Example 3

[0065] A method for preparing a high-precision stretchable flexible fabric circuit, the specific preparation process is as follows:

[0066] Step 1: Preparation of liquid metal microdroplets modified by photocurable monomers: 600 mg of eutectic gallium-indium alloy and 15 mL of anhydrous ethanol were placed in a 20 mL glass bottle, and the glass bottle was immersed in an ice-water mixture, and the liquid level of the ice-water mixture reached 2 / 3 of the glass bottle. The probe of the ultrasonic cell crusher was inserted into the glass bottle, and the probe was kept at the lower 2 / 3 of the liquid level in the glass bottle. The ultrasonic power was set to 55% and the ultrasonic time was 8 min. After that, 40 mg of photocurable monomer 4-HBA was added to the glass bottle, and it was ensured that the liquid level of the ice-water mixture was at 2 / 3 of the glass bottle. The ultrasonic power was set to 70% and the ultrasonic time was 40 min, so that the solution in the glass bottle changed from light gray to dark gray. After placing the glass bottle in an ultrasonic cleaner for 24 hours, the solution was poured into a centrifuge tube, placed in a centrifuge and centrifuged at 3000 r / min for 5 minutes, and the supernatant was poured out. Finally, the precipitate in the centrifuge tube was placed in a freeze dryer and dried for 7 hours to obtain liquid metal microdroplets modified by photocurable monomers.

[0067] Step 2: Prepare liquid metal photolithography slurry: Add 500 mg of liquid metal droplets modified by photocurable monomers and 0.5 mL of anhydrous ethanol to a 2 mL brown glass bottle, keep it away from light, and place it in an ultrasonic cleaner for uniform dispersion. Then add 5 mmol 4-HBA, 0.03 mmol TPO, 0.0015 mmol PEGDA, 0.0015 mmol TMPTMA and 50 mg PEG in sequence. Add a magnetic stirrer and stir it on a magnetic stirrer for 12 hours.

[0068] Step 3: Treat the photoetched fabric with oxygen plasma: Place the nylon fabric in an oxygen plasma cleaning machine, set the vacuum pressure value to 900 Pa, the radio frequency power to 100 W, and the treatment time to 10 min.

[0069] Step 4: Photolithography to obtain flexible fabric circuit pattern: Soak the nylon fabric in the photolithography slurry for 5 seconds and lay it flat on the mask, then place another mask with the same pattern on it, position and fix it through the positioning holes to obtain a fabric and mask composite. Place a light source with a wavelength of 375nm on the fabric and mask composite and expose it for 20 seconds; flip the fabric and mask composite and expose it again for 20 seconds. After that, take the fabric out of the two masks, place it in a glass dish, and pour a mixed solution of anhydrous ethanol and deionized water in a volume ratio of 2:1 as a developer. Place the glass dish in an ultrasonic cleaner and treat it at room temperature for 45 seconds. After taking it out, let it air dry naturally to obtain a flexible fabric circuit pattern.

[0070] Step 5: Sintering the flexible fabric circuit pattern: Place the PET sheet on top of the fabric circuit pattern obtained by photolithography, use a metal rod to roll over the PET sheet, apply pressure and shear force to the fabric circuit pattern part, so that the shell of the liquid metal micro-droplet breaks, and the liquid metal inside flows out to form a continuous conductive path.

[0071] Step 6: The high-precision stretchable flexible fabric circuit is bent 30,000 times at 150° to test its resistance change. The results show that the resistance change rate of the fabric circuit is less than 1.1% ( Figure 7 ), showing excellent bending resistance and flexibility.

[0072] The advantage of the present invention is that liquid metal and photocurable monomers are used as functional slurries, and the low melting point, high conductivity, good fluidity and stretchability of liquid metal are utilized, combined with fabric double-sided photolithography technology, so that high-precision fabric circuits with stretchability, flexibility and mechanical stability can be prepared on the surfaces of various fabrics.

[0073] Although the above methods are illustrated and described as a series of structures for simplicity of explanation, it should be understood and appreciated that these methods are not specifically limited because according to one or more embodiments, some structures may occur in different orders and / or concurrently with other actions from those illustrated and described herein or not illustrated and described herein but understandable to those skilled in the art.

[0074] The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein, but should be granted the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a high-definition stretchable flexible fabric circuit, characterized in that: The specific preparation steps are as follows: (1) preparing liquid metal microdroplets modified by photocurable monomers; preparing liquid metal microdroplets in a solvent by an ultrasonic cell crusher, and modifying the monomers on the surface of the liquid metal microdroplets by hydroxyl groups; the liquid metal used is a eutectic gallium-indium alloy; the specific process is as follows: (a) 300-600 mg of eutectic gallium-indium alloy and 10-15 mL of anhydrous ethanol are placed in a glass bottle, and the glass bottle is immersed in an ice-water mixture. Then, the probe of an ultrasonic cell pulverizer is inserted into the glass bottle and maintained below the liquid level in the glass bottle, and ultrasonicated until the solution in the glass bottle changes from a clear and transparent state to a light gray state; (b) adding 20-40 mg of photocurable monomer 4-hydroxybutyl acrylate (4-HBA) into the glass bottle and continuing ultrasonication until the solution in the glass bottle changes from light gray to dark gray; (c) placing the glass bottle in an ultrasonic cleaning apparatus and allowing the hydroxyl groups in the photocurable monomer 4-HBA to fully react with the gallium oxide shell of the liquid metal microdroplets; (d) pouring the solution in the glass bottle into a centrifuge tube, centrifuging it in a centrifuge, pouring out the supernatant, and leaving the precipitate; placing the precipitate in the centrifuge tube in a freeze dryer to dry it, thereby obtaining liquid metal microdroplets modified by a photocurable monomer; (2) Preparing liquid metal photolithography slurry: uniformly dispersing liquid metal droplets modified with photocurable monomers, photocurable monomers, photoinitiators, crosslinking agents, and diluents in ethanol to obtain liquid metal photolithography slurry; the specific process of preparing the liquid metal photolithography slurry is as follows: Add 300-500 mg of the liquid metal microdroplets modified with the photocurable monomer obtained in step (1) and 0.2-0.5 mL of anhydrous ethanol into a light-proof glass bottle (e.g., a brown glass bottle), and place in an ultrasonic cleaner for uniform dispersion; Then, 2-5 mmol of photocurable monomer 4-HBA, 0.01-0.03 mmol of photoinitiator, 0.001-0.003 mmol of crosslinker and 30-50 mg of diluent are added in sequence; a magnetic stirrer is placed and stirred on a magnetic stirrer for 12-20 hours to obtain a liquid metal photolithography slurry that can be used for photolithography on fabrics; (3) first treating the fabric to be photolithographically processed with oxygen plasma to enhance the adhesion of the liquid metal photolithography slurry on the fabric surface; (4) immersing the oxygen plasma-treated fabric in a liquid metal photolithography slurry, taking it out and placing it on a photolithography platform, placing it between two mask plates for double-sided ultraviolet exposure, and using ethanol and deionized water as developer for development to obtain a high-definition, stretchable flexible fabric circuit pattern; (5) Sintering the high-definition, stretchable flexible fabric circuit pattern to obtain a conductive path, i.e., a high-definition, stretchable flexible fabric circuit.

2. The preparation method according to claim 1, characterized in that: In the step (1): In step (a), the glass bottle is immersed in the ice-water mixture until the liquid level of the ice-water mixture reaches 1 / 2 to 2 / 3 of the glass bottle; then the probe of the ultrasonic cell pulverizer is kept at the lower 1 / 2 to 2 / 3 of the liquid level in the glass bottle; the ultrasonic power is set to 45% to 70%, and the ultrasonic time is 5 to 10 minutes; In step (c), the glass bottle is placed in an ultrasonic cleaner for 15 to 30 hours; In step (b), ensure that the liquid level of the ice-water mixture is at 1 / 2 of the glass bottle; then set the ultrasonic power to 45% to 70% and the ultrasonic time to 25 to 40 minutes; In step (d), centrifuge at 3000 r / min for 5 to 25 min; and dry in a freeze dryer for 5 to 10 h.

3. The preparation method according to claim 1, characterized in that: In the step (2), the photoinitiator is trimethylbenzoyl-diphenylphosphine oxide TPO, the crosslinking agent is one or more of trimethylolpropane triacrylate TMPTMA and polyethylene glycol dimethacrylate PEGDA, and the diluent is polyethylene glycol PEG.

4. The preparation method according to claim 1, characterized in that: In the step (3), the specific process of treating the fabric to be photoetched with oxygen plasma is as follows: Place the fabric in an oxygen plasma cleaning machine, set the vacuum pressure to 900 Pa, the radio frequency power to 100-180 W, and the treatment time to 2-10 min; The fabric is one of polyester, nylon and cotton.

5. The preparation method according to claim 1, characterized in that: In the step (4), the soaking time is 5 to 10 seconds.

6. The preparation method according to claim 5, characterized in that: In the step (4), the specific process of performing photolithography on the photolithography platform is as follows: The soaked fabric is laid flat on the mask plate and fixed at the four corners, and then another mask plate with the same pattern is placed on it, positioned and fixed through the positioning holes to obtain a fabric and mask plate combination; a photolithography light source is placed on the fabric and mask plate combination, and exposed for 15 to 30 seconds; the fabric and mask plate combination is turned over and exposed again for 15 to 30 seconds; The mask is a tungsten sheet, contains a circuit pattern, and is provided with positioning holes; the wavelength of the photolithography light source is 350-390nm; After the exposure is completed, the fabric is taken out from the two masks, placed in a glass dish, and poured with developer; the glass dish is placed in an ultrasonic cleaner and treated at room temperature for 30 to 50 seconds; after being taken out, it is naturally air-dried to obtain a high-precision, stretchable flexible fabric circuit pattern.

7. The preparation method according to claim 6, characterized in that: In the step (4), the developer is a mixed solution of anhydrous ethanol and deionized water in a volume ratio of 1:1 to 2:

1.

8. The preparation method according to claim 1, characterized in that: In the step (5), the sintering is mechanical sintering by pressurization and friction. The outer shell of the liquid metal droplets modified by the photocurable monomer is broken during the sintering process, and the internal liquid metal flows out to form a conductive path, and finally a conductive path on the fabric is obtained.

9. The high-definition stretchable flexible fabric circuit obtained by the preparation method according to any one of claims 1 to 8, wherein the minimum circuit width can reach 100 μm and the resistance is 5 to 10 Ω.

Images