A polystyrene / graphene oxide microsphere, a strain sensing fabric and a preparation method

Abstract

The application discloses a polystyrene / graphene oxide microsphere, a strain sensing fabric and a preparation method, the microsphere preparation method is that cationic surfactant is added into a polystyrene microsphere solution, then graphene oxide solution is added after mixing, and PS / GO microspheres are obtained through stirring; the preparation method of the strain sensing fabric comprises pretreatment, immersion, preparation of a conductive elastic fabric and preparation of a fabric strain sensor. Through cationic modification, the application loads graphene oxide on the surface of the polystyrene microsphere, then combines the polystyrene microsphere on the elastic fabric, reduces PS / GO into PS / rGO through a green reducing agent ascorbic acid to prepare conductive microspheres, and the elastic fabric is endowed with conductivity to prepare a flexible strain sensor. The prepared conductive microspheres have good dispersibility and size stability, and the prepared fabric strain sensor has a wide strain range of 0-90%, and the maximum sensitivity can reach 10.44.

Description

Technical Field

[0001] This invention belongs to the field of functional microspheres and functional fabrics, specifically relating to a polystyrene / graphene oxide microsphere, a strain-sensing fabric, and a preparation method thereof. Background Technology

[0002] Conductive polymer composites have spearheaded technological revolutions in aerospace, electronic materials, energy materials, sensors, and many civilian materials. Developing high-performance, multi-purpose conductive composites plays a crucial role in societal progress and development. Polystyrene (PS) microspheres are among the most widely used commercial polymers due to their ease of processing, relatively good chemical resistance, low density, and high performance / price ratio. However, their poor conductivity limits their application in electronic products. Graphene oxide is considered one of the main derivatives of graphene. Abundant oxygen-containing functional groups on graphene oxide can serve as binding components or sites for nanoparticles, while the wrinkled overall shape can effectively prevent nanoparticle aggregation to a certain extent, while simultaneously imparting good conductivity to the nanoparticles. Therefore, an effective method is needed to overcome the poor conductivity of polystyrene microspheres and to uniformly disperse graphene oxide within polystyrene microspheres, reducing them to form highly conductive polymer composite microspheres.

[0003] In recent years, with the development of technology, intelligent wearable devices, electronic skin, human-computer interaction, soft robots, and personalized health monitoring devices have begun to enter people's lives. To meet these needs, flexible and stretchable sensors have received widespread attention due to their lightweight and wide detection range. Fabric-based sensors, with their small size, high adhesion to the object being measured, flexibility, and stretchability, have become a current research hotspot. Therefore, providing a method for preparing conductive microspheres and applying them to elastic fabrics to create fabric strain-sensing fabrics with high sensitivity, good stability, and a wide strain sensing range is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a polystyrene / graphene oxide microsphere, a strain-sensing fabric, and a preparation method thereof.

[0005] The objective of this invention is achieved through the following technical solution: a method for preparing polystyrene / graphene oxide microspheres, characterized in that a cationic surfactant is added to a polystyrene microsphere solution, and after mixing, a graphene oxide solution is added, wherein the mass of the added graphene oxide is 1-20% of the mass of the polystyrene microspheres, and the mixture is stirred to obtain PS / GO microspheres; wherein the cationic surfactant is one or more of dodecyl dimethyl benzyl ammonium chloride, hexadecyl trimethyl ammonium chloride, octadecyl trimethyl ammonium bromide, or dodecyl pyridine ammonium chloride.

[0006] Furthermore, the preparation method of the polystyrene microspheres is as follows: using styrene as the reactant monomer, azobisisobutyronitrile as the catalyst, and polyvinylpyrrolidone as the stabilizer, the reaction is carried out in a reaction medium of ethanol and water for 4 to 8 hours, with the volume ratio of ethanol to water being 2 to 9:1. After the reaction is completed, the solution is centrifuged and washed to obtain polystyrene microspheres.

[0007] Further, the preparation method of the graphene oxide is as follows: using graphene as raw material, mixing it evenly and stirring it in an acid solution, then cooling and diluting it with distilled water, centrifuging it and washing the solid to obtain graphene oxide; wherein, the acid is at least one of concentrated sulfuric acid, concentrated nitric acid, concentrated hydrochloric acid or perchloric acid.

[0008] A polystyrene / graphene oxide microsphere was prepared using the method described above.

[0009] A method for preparing a strain-sensing fabric, comprising the following steps: S1. Pretreatment: Place the elastic fabric in a Soxhlet extractor containing acetone to wash away the organic matter on the elastic fabric, heat to 60-80℃, and after the temperature stabilizes, reflux for 1.5-2.5h to obtain the pretreated elastic fabric. S2. Impregnation: The pretreated elastic fabric from step S1 is impregnated in an aqueous solution of the polystyrene / graphene oxide microspheres described in claim 3, and ultrasonically treated for 30-60 minutes, then dried. S3. Preparation of conductive elastic fabric: The dried elastic fabric is placed in an aqueous solution containing ascorbic acid, heated to 70-100℃, and ultrasonically reacted for 2-4 hours to reduce the polystyrene / graphene oxide microspheres on the elastic fabric to PS / rGO conductive microspheres and then dried to make the elastic fabric a conductive elastic fabric. S4. Fabrication of a fabric strain sensor: Two copper wires are connected to the two ends of a dry, conductive elastic fabric to fabricate a strain sensor fabric.

[0010] Furthermore, the concentration of ascorbic acid in the aqueous solution containing ascorbic acid is 0.01-1%.

[0011] Furthermore, the mass percentage concentration of the polystyrene / graphene oxide microsphere aqueous solution is 1-10%.

[0012] The strain-sensing fabric prepared by the above method.

[0013] This invention has the following advantages: It discloses a polystyrene / graphene oxide microsphere, a strain-sensing fabric, and its preparation method. Graphene oxide is loaded onto the surface of polystyrene microspheres through cationic modification, and then these microspheres are bonded to an elastic fabric. Conductive microspheres are prepared by reducing PS / GO to PS / rGO using ascorbic acid, a green reducing agent, and this process imparts conductivity to the elastic fabric, thus creating a flexible strain sensor. The prepared conductive microspheres exhibit good dispersibility and dimensional stability, and the fabric strain sensor has a wide strain range of 0-90%, with a maximum sensitivity of 10.44. This invention not only overcomes the poor conductivity of polystyrene microspheres but also uses green chemical reagents to reduce graphene oxide to prepare conductive microspheres. Furthermore, the fabric strain sensor can detect a wide strain range and has high sensitivity. Attached Figure Description

[0014] Figure 1 Conductivity curves of fabric strain sensors with different GO contents in Examples 1-5 of this invention; Figure 2 Scanning electron microscope image of the surface morphology of PS / GO polymer microspheres prepared in this invention; Figure 3 The image shows the surface morphology of the PS / rGO conductive polymer microspheres prepared in this invention using a scanning electron microscope. Figure 4 Scanning electron microscope (SEM) images of the fabric strain sensor before (a, b) and after (c, d) fabric strain sensor prepared according to the present invention. Figure 5 This is the curve showing the relationship between the relative resistance change and strain of the fabric strain sensor of the present invention; Figure 6 This is a periodic test curve showing the relative resistance change of the flexible fabric sensor of the present invention under different tensile strains. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments. The scope of protection of the present invention is not limited to the following description: Example 1: A method for preparing a strain-sensing fabric, comprising the following steps: S1. Pretreatment: Place the elastic fabric in a Soxhlet extractor containing acetone to clean the organic matter on the elastic fabric, heat to 60°C, and reflux for 1.5 hours after the temperature stabilizes to obtain a clean pretreated elastic fabric. S2. Impregnation: S21. Preparation of graphene oxide: Graphene is used as raw material, mixed evenly and stirred in concentrated sulfuric acid solution, then cooled and diluted with distilled water. After centrifugation, the solid is washed to obtain graphene oxide. S22. Preparation of polystyrene / graphene oxide microspheres: using styrene as the reactant monomer, azobisisobutyronitrile as the catalyst, and polyvinylpyrrolidone as the stabilizer, the reaction was carried out in a reaction medium of ethanol and water for 4 hours with a volume ratio of ethanol to water of 2:1. After the reaction was completed, the solution was centrifuged and washed to obtain polystyrene microspheres. S23. Preparation of polystyrene / graphene oxide microspheres: A cationic surfactant is added to a polystyrene microsphere solution, and after mixing, a graphene oxide solution is added. The mass of graphene oxide added is 1% of the mass of the polystyrene microspheres. The mixture is stirred to obtain PS / GO microspheres; wherein, the cationic surfactant is dodecyl dimethyl benzyl ammonium chloride. S24. The pretreated elastic fabric from step S1 is immersed in an aqueous solution of polystyrene / graphene oxide microspheres and ultrasonically treated for 30 minutes. After completion, it is dried. The mass percentage concentration of the aqueous solution of polystyrene / graphene oxide microspheres is 1%. S3. Preparation of conductive elastic fabric: The dried elastic fabric is placed in an aqueous solution containing ascorbic acid, wherein the concentration of ascorbic acid in the aqueous solution is 0.01%, the temperature is raised to 70°C, and the reaction is ultrasonic for 2 hours to reduce the polystyrene / graphene oxide microspheres on the elastic fabric to PS / rGO conductive microspheres and then dried to make the elastic fabric a conductive elastic fabric. S4. Fabrication of a fabric strain sensor: Two copper wires are connected to the two ends of a dry, conductive elastic fabric to fabricate a strain sensor fabric.

[0016] Example 2: A method for preparing a strain-sensing fabric, comprising the following steps: S1. Pretreatment: Place the elastic fabric in a Soxhlet extractor containing acetone to clean the organic matter on the elastic fabric, heat to 80°C, and reflux for 2.5 hours after the temperature stabilizes to obtain a clean pretreated elastic fabric. S2. Impregnation: S21. Preparation of graphene oxide: Using graphene as raw material, it is mixed evenly and stirred in a mixed solution of concentrated nitric acid and concentrated hydrochloric acid, then cooled and diluted with distilled water. After centrifugation, the solid is washed to obtain graphene oxide. S22. Preparation of polystyrene / graphene oxide microspheres: using styrene as the reactant monomer, azobisisobutyronitrile as the catalyst, and polyvinylpyrrolidone as the stabilizer, the reaction was carried out in a reaction medium of ethanol and water for 8 hours with a volume ratio of ethanol to water of 9:1. After the reaction was completed, the solution was centrifuged and washed to obtain polystyrene microspheres. S23. Preparation of polystyrene / graphene oxide microspheres: A cationic surfactant is added to a polystyrene microsphere solution, and after mixing, a graphene oxide solution is added. The mass of graphene oxide added is 20% of the mass of the polystyrene microspheres. The mixture is stirred to obtain PS / GO microspheres. The cationic surfactant is a mixture of hexadecyltrimethylammonium chloride and octadecyltrimethylammonium bromide. S24. The pretreated elastic fabric from step S1 is immersed in a polystyrene / graphene oxide microsphere aqueous solution and ultrasonically treated for 60 minutes. After completion, it is dried. The polystyrene / graphene oxide microsphere aqueous solution has a mass percentage concentration of 10%. S3. Preparation of conductive elastic fabric: The dried elastic fabric is placed in an aqueous solution containing ascorbic acid, wherein the concentration of ascorbic acid in the aqueous solution is 1%, the temperature is raised to 100°C, and the reaction is ultrasonic for 4 hours to reduce the polystyrene / graphene oxide microspheres on the elastic fabric to PS / rGO conductive microspheres and then dried to make the elastic fabric a conductive elastic fabric. S4. Fabrication of a fabric strain sensor: Two copper wires are connected to the two ends of a dry, conductive elastic fabric to fabricate a strain sensor fabric.

[0017] Example 3: A method for preparing a strain-sensing fabric, comprising the following steps: S1. Pretreatment: Place the elastic fabric in a Soxhlet extractor containing acetone to clean the organic matter on the elastic fabric, heat to 70°C, and reflux for 2 hours after the temperature stabilizes to obtain a clean pretreated elastic fabric. S2. Impregnation: S21. Preparation of graphene oxide: Graphene is used as a raw material, mixed evenly and stirred in an acid solution, then cooled and diluted with distilled water. After centrifugation, the solid is washed to obtain graphene oxide; wherein, the acid is a mixture of concentrated sulfuric acid, concentrated hydrochloric acid and perchloric acid. S22. Preparation of polystyrene / graphene oxide microspheres: using styrene as the reactant monomer, azobisisobutyronitrile as the catalyst, and polyvinylpyrrolidone as the stabilizer, the reaction was carried out in a reaction medium of ethanol and water for 5 h with a volume ratio of ethanol to water of 5:1. After the reaction was completed, the solution was centrifuged and washed to obtain polystyrene microspheres. S23. Preparation of polystyrene / graphene oxide microspheres: A cationic surfactant is added to a polystyrene microsphere solution, and after mixing, a graphene oxide solution is added. The mass of graphene oxide added is 10% of the mass of the polystyrene microspheres. The mixture is stirred to obtain PS / GO microspheres. The cationic surfactant is a mixture of dodecyl dimethyl benzyl ammonium chloride, hexadecyl trimethyl ammonium chloride, and dodecyl pyridine ammonium chloride. S24. The pretreated elastic fabric from step S1 is immersed in an aqueous solution of polystyrene / graphene oxide microspheres and ultrasonically treated for 45 minutes. After completion, it is dried. The mass percentage concentration of the aqueous solution of polystyrene / graphene oxide microspheres is 5%. S3. Preparation of conductive elastic fabric: The dried elastic fabric is placed in an aqueous solution containing ascorbic acid, wherein the concentration of ascorbic acid in the aqueous solution is 0.5%, the temperature is raised to 85°C, and the reaction is ultrasonic for 3 hours to reduce the polystyrene / graphene oxide microspheres on the elastic fabric to PS / rGO conductive microspheres and then dried to make the elastic fabric a conductive elastic fabric. S4. Fabrication of a fabric strain sensor: Two copper wires are connected to the two ends of a dry, conductive elastic fabric to fabricate a strain sensor fabric.

[0018] The following experiments illustrate the beneficial effects of this invention: Example 1 (1) Dissolve 10g of polyvinylpyrrolidone in a mixture of 80g of anhydrous ethanol and 20g of water, then transfer the solution to a three-necked flask and raise the temperature to 65°C. Add 25g of styrene monomer containing 0.8g of azobisisobutyronitrile dropwise, raise the temperature to 70°C, and polymerize at 70°C for 8 hours with stirring. After the reaction is complete, centrifuge the emulsion sample at 6000 rpm for 5 minutes to obtain polystyrene (PS) microspheres.

[0019] (2) Weigh 1g of graphite powder and dissolve 50ml of concentrated sulfuric acid in a three-necked flask. Slowly add 9g of KMnO4 in an ice-water bath and stir. Heat the apparatus to 40℃ and stir for 1h. Slowly add 150ml of deionized water, then heat to 95℃ and stir for 15min. After cooling to room temperature, add 500ml of water and 15ml of H2O2 (30%). Use a high-speed centrifuge at 3000 rpm for 5 minutes to obtain a precipitate. Then add a large amount of deionized water. After the precipitate floats up, let it stand. Repeat the steps several times to obtain graphene oxide.

[0020] (3) Take 1g of polystyrene microspheres prepared in step (1) and disperse them in 30ml of deionized water. Add octadecyltrimethylammonium bromide, a cationic surfactant with a mass fraction of 1% of polystyrene microspheres. Stir for 15 minutes to make the surface positively charged. Add 0.01g of graphene oxide prepared in step 2 and stir for 1h to prepare PS / GO microspheres.

[0021] (4) Place the pretreated elastic polyester-spandex fabric in a PS / GO microsphere solution and ultrasonically disperse it for 2 hours so that PS / GO can be adsorbed onto the elastic fabric. After completion, place it in an oven to dry.

[0022] (5) Add 0.01g of ascorbic acid solution and disperse it in 30ml of deionized water. Place the elastic fabric prepared in step (4) in the solution and heat it to 90℃. The reaction time is 2h. After the reaction is completed, dry it to obtain conductive elastic fabric.

[0023] (6) Connect the two copper wires to the two ends of the dry conductive elastic fabric prepared in step (5) to obtain the fabric strain sensor made of conductive microspheres.

[0024] Example 2 (1) Dissolve 10g of polyvinylpyrrolidone in a mixture of 80g of anhydrous ethanol and 20g of water, then transfer the solution to a three-necked flask and raise the temperature to 65°C. Add 20g of styrene monomer containing 0.6g of azobisisobutyronitrile dropwise, raise the temperature to 70°C, and polymerize at 70°C for 8 hours with stirring. After the reaction is complete, centrifuge the emulsion sample at 6000 rpm for 5 minutes to obtain polystyrene (PS) microspheres.

[0025] (2) Weigh 1g of graphite powder and dissolve it in 40ml of concentrated sulfuric acid in a three-necked flask. Slowly add 8g of KMnO4 in an ice-water bath and stir. Heat the apparatus to 40℃ and stir for 1h. Slowly add 150ml of deionized water, then heat to 95℃ and stir for 15min. After cooling to room temperature, add 500ml of water and 12ml of H2O2 (30%). Use a high-speed centrifuge at 3000 rpm for 5 minutes to obtain a precipitate. Then add a large amount of deionized water. After the precipitate floats up, let it stand. Repeat the steps several times to obtain graphene oxide.

[0026] (3) Take 1g of polystyrene microspheres prepared in step (1) and disperse them in 30ml of deionized water. Add octadecyltrimethylammonium bromide, a cationic surfactant with a mass fraction of 2% of polystyrene microspheres. Stir for 15 minutes to make the surface positively charged. Add 0.05g of graphene oxide prepared in step 2 and stir for 1h to prepare PS / GO microspheres.

[0027] (4) Place the pretreated elastic polyester-spandex fabric in a PS / GO microsphere solution and ultrasonically disperse it for 2 hours so that PS / GO can be adsorbed onto the elastic fabric. After completion, place it in an oven to dry.

[0028] (5) Add 0.02g of ascorbic acid solution and disperse it in 30ml of deionized water. Place the elastic fabric prepared in step (4) in the solution and heat it to 90℃. The reaction time is 2h. After the reaction is completed, dry it to obtain conductive elastic fabric.

[0029] (6) Connect the two copper wires to the two ends of the dry conductive elastic fabric prepared in step (5) to obtain the fabric strain sensor made of conductive microspheres.

[0030] Example 3 (1) Dissolve 10g of polyvinylpyrrolidone in a mixture of 80g of anhydrous ethanol and 20g of water, then transfer the solution to a three-necked flask and raise the temperature to 65°C. Add 15g of styrene monomer containing 0.4g of azobisisobutyronitrile dropwise, raise the temperature to 70°C, and polymerize at 70°C for 8 hours with stirring. After the reaction is complete, centrifuge the emulsion sample at 6000 rpm for 5 minutes to obtain polystyrene (PS) microspheres.

[0031] (2) Weigh 1g of graphite powder and dissolve 30ml of concentrated sulfuric acid in a three-necked flask. Slowly add 7g of KMnO4 in an ice-water bath and stir. Heat the apparatus to 40℃ and stir for 1h. Slowly add 150ml of deionized water, then heat to 95℃ and stir for 15min. Cool to room temperature and add 500ml of water and 10ml of H2O2 (30%). Use a high-speed centrifuge at 3000 rpm for 5 minutes to obtain a precipitate. Then add a large amount of deionized water. After the precipitate floats up, let it stand. Repeat the steps several times to obtain graphene oxide.

[0032] (3) Take 1g of polystyrene microspheres prepared in step (1) and disperse them in 30ml of deionized water. Add octadecyltrimethylammonium bromide, a cationic surfactant with a mass fraction of 3% of polystyrene microspheres. Stir for 15 minutes to make the surface positively charged. Add 0.1g of graphene oxide prepared in step 2 and stir for 1h to prepare PS / GO microspheres.

[0033] (4) Place the pretreated elastic polyester-spandex fabric in a PS / GO microsphere solution and ultrasonically disperse it for 2 hours so that PS / GO can be adsorbed onto the elastic fabric. After completion, place it in an oven to dry.

[0034] (5) Add 0.03g of ascorbic acid solution and disperse it in 30ml of deionized water. Place the elastic fabric prepared in step (4) in the solution and heat it to 90℃. The reaction time is 2h. After the reaction is completed, dry it to obtain conductive elastic fabric.

[0035] (6) Connect the two copper wires to the two ends of the dry conductive elastic fabric prepared in step (5) to obtain the fabric strain sensor made of conductive microspheres.

[0036] Example 4 (1) Dissolve 10g of polyvinylpyrrolidone in a mixture of 80g of anhydrous ethanol and 20g of water, then transfer the solution to a three-necked flask and raise the temperature to 65°C. Add 15g of styrene monomer containing 0.4g of azobisisobutyronitrile dropwise, raise the temperature to 70°C, and polymerize at 70°C for 8 hours with stirring. After the reaction is complete, centrifuge the emulsion sample at 6000 rpm for 5 minutes to obtain polystyrene (PS) microspheres.

[0037] (2) Weigh 1g of graphite powder and dissolve 30ml of concentrated sulfuric acid in a three-necked flask. Slowly add 7g of KMnO4 in an ice-water bath and stir. Heat the apparatus to 40℃ and stir for 1h. Slowly add 150ml of deionized water, then heat to 95℃ and stir for 15min. Cool to room temperature and add 500ml of water and 10ml of H2O2 (30%). Use a high-speed centrifuge at 3000 rpm for 5 minutes to obtain a precipitate. Then add a large amount of deionized water. After the precipitate floats up, let it stand. Repeat the steps several times to obtain graphene oxide.

[0038] (3) Take 1g of polystyrene microspheres prepared in step (1) and disperse them in 30ml of deionized water. Add octadecyltrimethylammonium bromide, a cationic surfactant with a mass fraction of 3% of polystyrene microspheres. Stir for 15 minutes to make the surface positively charged. Add 0.15g of graphene oxide prepared in step 2 and stir for 1h to prepare PS / GO microspheres.

[0039] (4) Place the pretreated elastic polyester-spandex fabric in a PS / GO microsphere solution and ultrasonically disperse it for 2 hours so that PS / GO can be adsorbed onto the elastic fabric. After completion, place it in an oven to dry.

[0040] (5) Add 0.03g of ascorbic acid solution and disperse it in 30ml of deionized water. Place the elastic fabric prepared in step (4) in the solution and heat it to 90℃. The reaction time is 2h. After the reaction is completed, dry it to obtain conductive elastic fabric.

[0041] (6) Connect the two copper wires to the two ends of the dry conductive elastic fabric prepared in step (5) to obtain the fabric strain sensor made of conductive microspheres.

[0042] Example 5 (1) Dissolve 10g of polyvinylpyrrolidone in a mixture of 80g of anhydrous ethanol and 20g of water, then transfer the solution to a three-necked flask and raise the temperature to 65°C. Add 10g of styrene monomer containing 0.2g of azobisisobutyronitrile dropwise, raise the temperature to 70°C, and polymerize at 70°C for 8 hours with stirring. After the reaction is complete, centrifuge the emulsion sample at 6000 rpm for 5 minutes to obtain polystyrene (PS) microspheres.

[0043] (2) Weigh 1g of graphite powder and dissolve 30ml of concentrated sulfuric acid in a three-necked flask. Slowly add 6g of KMnO4 in an ice-water bath and stir. Heat the apparatus to 40℃ and stir for 1h. Slowly add 150ml of deionized water, then heat to 95℃ and stir for 15min. Cool to room temperature and add 500ml of water and 8ml of H2O2 (30%). Use a high-speed centrifuge at 3000 rpm for 5 minutes to obtain a precipitate. Then add a large amount of deionized water. After the precipitate floats up, let it stand. Repeat the steps several times to obtain graphene oxide.

[0044] (3) Take 1g of polystyrene microspheres prepared in step (1) and disperse them in 30ml of deionized water. Add octadecyltrimethylammonium bromide, a cationic surfactant with a mass fraction of 3% of polystyrene microspheres. Stir for 15 minutes to make the surface positively charged. Add 0.2g of graphene oxide prepared in step 2 and stir for 1h to prepare PS / GO microspheres.

[0045] (4) Place the pretreated elastic polyester-spandex fabric in a PS / GO microsphere solution and ultrasonically disperse it for 2 hours so that PS / GO can be adsorbed onto the elastic fabric. After completion, place it in an oven to dry.

[0046] (5) Add 0.04g of ascorbic acid solution and disperse it in 30ml of deionized water. Place the elastic fabric prepared in step (4) in the solution and heat it to 90℃. The reaction time is 2h. After the reaction is completed, dry it to obtain conductive elastic fabric.

[0047] (6) Connect the two copper wires to the two ends of the dry conductive elastic fabric prepared in step (5) to obtain the fabric strain sensor made of conductive microspheres.

[0048] The fabric strain sensors obtained in Examples 1-5 were subjected to conductivity tests. Figure 1 It can be seen that the conductivity of the fabric strain sensor varies from small to large under different GO weight ratios of 1%, 5%, 10%, 15%, and 20%, reaching its optimum at 15% GO. The sharp increase in conductivity with increasing GO content is due to excessively high GO content. Therefore, further characterization of the conductive microspheres with 15% GO content and the fabric strain sensor will be conducted next. Figure 2 The appearance morphology of PS / GO polymer microspheres with a GO content of 15% was analyzed, and it was found that GO was completely coated on the surface of PS microspheres and interconnected with each other.

[0049] Figure 3 The surface morphology of PS / rGO conductive microspheres with a GO content of 15% was analyzed, and it was found that after reduction, rGO still coated the surface of PS microspheres and formed a conductive network.

[0050] Figure 4 The appearance morphology of the strain fabric sensor with 15% GO content was analyzed. It was found that the fabric surface was smooth and flat before the conductive microspheres were treated (a, b). After the conductive microspheres were treated, obvious PS / rGO microspheres could be found on the fabric surface, and the conductive microspheres were interconnected to form a conductive network.

[0051] Figure 5The fabric dynamic resistance tester can be used to measure the real-time sensitivity of a strain sensor for fabric with 15% GO content during dynamic deformation, obtaining the trend of fabric resistance value changing with tensile deformation. From the tensile degree of 0-90%, the graph shows that the maximum ΔR / R0 is directly proportional to the applied strain, indicating excellent fabric strain sensing performance with high strain coefficient and linearity.

[0052] Figure 6 The fabric dynamic resistance tester can be used to measure the periodic test of the relative resistance change of a strain sensor with 15% GO content under different tensile strains. The figure shows that during the periodic tensile process of 5%-90%, the resistance change of the strain sensor ∆R / R0 is the same when the strain is applied and removed. Moreover, after the strain is removed, the resistance value can be restored to the original resistance value, which has good cycle stability.

[0053] As demonstrated by the above experimental examples, this invention provides a strain-sensing fabric and its preparation method. The method not only produces polymer microspheres with good conductivity, but also allows for the fabrication of a strain sensor with high flexibility, high sensitivity, and a wide strain range by treating the polymer microspheres onto the fabric. This fabric strain sensor overcomes the brittleness and bulkiness of traditional metal or semiconductor strain sensors, and possesses great potential in fields such as smart clothing and health monitoring.

[0054] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, are covered within the scope of protection of the present invention.

Claims

1. A method for preparing a strain-sensing fabric, characterized in that, It includes the following steps: S1. Pretreatment: Place the elastic fabric in a Soxhlet extractor containing acetone to clean the organic matter on the elastic fabric, heat to 60-80℃, and after the temperature stabilizes, reflux for 1.5-2.5h to obtain the pretreated elastic fabric. S2. Impregnation: The pretreated elastic fabric from step S1 is impregnated in an aqueous solution of polystyrene / graphene oxide microspheres and ultrasonically treated for 30–60 min, then dried; the mass percentage concentration of the polystyrene / graphene oxide microsphere aqueous solution is 1–10%. The preparation method of the polystyrene / graphene oxide microspheres is as follows: A cationic surfactant is added to a polystyrene microsphere solution, and after mixing, a graphene oxide solution is added. The mass of graphene oxide added is 1-20% of the mass of the polystyrene microspheres, and the mixture is stirred to obtain PS / GO microspheres. The cationic surfactant is octadecyltrimethylammonium bromide. The amount of cationic surfactant added is 1%, 2%, or 3% of the mass of the polystyrene microspheres. S3. Preparation of conductive elastic fabric: The dried elastic fabric is placed in an aqueous solution containing ascorbic acid, heated to 70-100℃, and ultrasonically reacted for 2-4 hours to reduce the polystyrene / graphene oxide microspheres on the elastic fabric to PS / rGO conductive microspheres. The fabric is then dried to transform it into a conductive elastic fabric. The concentration of ascorbic acid in the aqueous solution is 0.01-1%. S4. Fabrication of a fabric strain sensor: Two copper wires are connected to the two ends of a dry, conductive elastic fabric to prepare a strain sensor fabric.

2. The method for preparing a strain-sensing fabric as described in claim 1, characterized in that, The polystyrene microspheres are prepared by: using styrene as the reactant monomer, azobisisobutyronitrile as the catalyst, and polyvinylpyrrolidone as the stabilizer, reacting in a reaction medium of ethanol and water for 4-8 hours, with a volume ratio of ethanol to water of 2-9:

1. After the reaction, the solution is centrifuged and washed to obtain polystyrene microspheres.

3. The method for preparing a strain-sensing fabric as described in claim 1, characterized in that, The method for preparing the graphene oxide is as follows: graphene is used as a raw material, mixed evenly and stirred in an acid solution, then cooled and diluted with distilled water, and the solid is washed after centrifugation to obtain graphene oxide; wherein the acid is at least one of concentrated sulfuric acid, concentrated nitric acid, concentrated hydrochloric acid or perchloric acid.

4. The strain-sensing fabric prepared by any one of the preparation methods described in claims 1-3.

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