A polystyrene microsphere-enhanced MXene-based flexible pressure sensing material, its preparation method and application

Abstract

This invention relates to a polystyrene microsphere-enhanced MXene-based flexible pressure sensing material, its preparation method, and its applications, belonging to the field of flexible sensing and nanomaterial preparation technology. This invention addresses the shortcomings of existing pure MXene-based flexible pressure sensing materials, such as low sensitivity, slow dynamic response, and small pressure response range. This invention uses MXene as a substrate and introduces modified microsphere-shaped polystyrene material to prepare a polystyrene microsphere-enhanced MXene-based flexible pressure sensing material. First, the surface of the polystyrene microspheres modified with a strong cationic polyelectrolyte solution exhibits positive charge, allowing for simple electrostatic assembly with MXene nanosheets to form a stable composite film. Second, thanks to the introduction of polystyrene microspheres, while ensuring the overall stability of the composite material, the stress within the structure is more concentrated, thereby significantly improving the pressure sensing performance.

Description

Technical Field

[0001] This invention belongs to the field of flexible sensing and nanomaterial preparation technology. Specifically, it relates to a polystyrene microsphere-enhanced MXene-based flexible pressure sensing material, its preparation method, and its application. Background Technology

[0002] Sensors play a crucial role in modern technology and daily life. Among them, pressure sensors are the most widely used, playing a vital role in industrial monitoring, healthcare, robotics, and wearable electronics. However, existing pressure sensing systems are mainly based on rigid sensing elements, which have drawbacks such as difficulty in conforming to complex curved surfaces and poor mechanical compatibility. Flexibility is an inevitable trend in the development of pressure sensors. Flexible pressure sensing materials, as the core of flexible pressure sensors, can convert external pressure stimuli into electrical signals according to specific rules, fundamentally determining the overall performance of flexible pressure sensors. Therefore, developing high-performance flexible pressure sensing materials is of great significance for promoting the development of flexible pressure sensors and their practical application in the entire field of flexible electronics.

[0003] MXenes, as two-dimensional transition metal carbon and / or nitrides, possess metallic conductivity, abundant surface functional groups, and good mechanical flexibility, making them promising for applications in flexible pressure sensing. However, pure MXenes materials are prone to problems such as layer stacking and overly dense structures, which limit their pressure-sensitive properties and response range. Summary of the Invention

[0004] This invention addresses the shortcomings of existing pure MXene-based flexible pressure sensing materials, such as low sensitivity, slow dynamic response, and small pressure response range, by providing a polystyrene microsphere-enhanced MXene-based flexible pressure sensing material, its preparation method, and its applications.

[0005] This invention introduces polystyrene microspheres into the MXenes system to construct a fine microstructure, which can synergistically improve the sensitivity, response range and mechanical adaptability of the material, thereby enhancing the practicality of MXenes materials in the field of flexible pressure sensing, and has important research value and application prospects.

[0006] To address the aforementioned technical problems, the present invention adopts the following technical solution: The purpose of this invention is to provide a method for preparing the above-mentioned polystyrene microsphere-enhanced MXene-based flexible pressure sensing material, comprising the following steps: Step 1: Pour lithium fluoride powder into dilute hydrochloric acid, stir under constant temperature heating until uniform, add MAX phase powder, stir under constant temperature heating to react, centrifuge, collect the precipitate, pour the precipitate into dilute sulfuric acid, stir, centrifuge and take the precipitate, wash with deionized water several times and centrifuge until neutral, collect the upper black liquor to obtain MXene colloidal solution. Step 2: Using a strong cationic polyelectrolyte, the surface of polystyrene microspheres is modified by electrostatic self-assembly technology to obtain surface-modified polystyrene microspheres; Step 3: Take an appropriate amount of MXene colloidal solution, dilute it with deionized water, and stir thoroughly to obtain an MXene dispersion. Then, add the modified polystyrene microspheres to the MXene dispersion, stir until uniform, load them onto the surface of a filter membrane through vacuum filtration, and vacuum dry to obtain the flexible pressure sensing material.

[0007] The method for preparing the MXene colloidal solution in step 1 is the modified minimum strength stratification method (MILD).

[0008] Further specifying, the purity of the lithium fluoride powder used in step 1 is 95%~99% (AR); preferably, the purity is 99% (AR).

[0009] Further specifying, the concentration of dilute hydrochloric acid used in step 1 is 7~11 mol / L; preferably 8~9 mol / L.

[0010] Further specifying, the mass ratio of lithium fluoride to hydrochloric acid used in step 1 is 1:14~15; preferably 1:14.5.

[0011] Further specifying, the constant temperature heating in step 1 is 30~50 ℃; preferably 35~38 ℃.

[0012] Further specifying, the stirring time in step 1 is 0.5~2.5 h; preferably 2 h.

[0013] Further specifying, the MAX phase powder in step 1 is a ternary layered carbon and / or nitride ceramic, wherein M represents a metal element, A represents a main group element, and X represents carbon and / or nitrogen; preferably Ti3AlC2.

[0014] Further specifying, in step 1, the mass ratio of MAX phase powder to lithium fluoride is 1:1.5~3; preferably 1:1.5~2.

[0015] Further specifying, the constant temperature heating in step 1 is 30~50 ℃; preferably 35~38 ℃.

[0016] Further specifying, the heating and stirring time in step 1 is 40~50 h; preferably 46~48 h.

[0017] Further specifying, the first centrifugation speed in step 1 is 4000~6000 rpm; preferably 4500~5500 rpm.

[0018] Further specifying, the first centrifugation time in step 1 is 5~15 min; preferably 5~8 min.

[0019] Further specifying, the concentration of dilute sulfuric acid used in step 1 is 2~3.5 mol / L; preferably 2.5 mol / L.

[0020] Further specifying, the mass ratio of dilute sulfuric acid to MAX phase powder used in step 1 is 18~23:1; preferably 23:1.

[0021] Further specifying, the stirring time in step 1 is 50~100 min; preferably 60~70 min.

[0022] Further specifying, the mass ratio of the first deionized water to MXene precipitate in step 1 is 3~10:1; preferably 5~8:1.

[0023] Further specifying, in step 1, the first wash with deionized water can be a hand-cranked wash, with a hand-cranking time of 3 to 10 minutes; preferably 5 to 7 minutes.

[0024] Further specifying, the second centrifugation speed in step 1 is 3000~6000 rpm; preferably 4500~5500 rpm.

[0025] Further specifying, the second centrifugation time in step 1 is 5~10 min; preferably 5~8 min.

[0026] Further specifying, the number of centrifugations in step 1 is 2 to 6 times; preferably 3 to 4 times.

[0027] Further specified, in step 1, the pH value of the supernatant is maintained at 6.5-8; preferably 7-7.5.

[0028] Further specifying, the mass ratio of the second deionized water to MXene precipitate in step 1 is 3~5:1; preferably 3~4:1.

[0029] Further specifying, the second wash with deionized water in step 1 can be a hand-shaking wash, with a shaking time of 4~10 minutes; preferably 5~8 minutes.

[0030] Further specifying, the third centrifugation speed in step 1 is 4000~6000 rpm; preferably 4500~5500 rpm.

[0031] Further specifying, the third centrifugation time in step 1 is 5~10 min; preferably 5~8 min.

[0032] Further specifying, the number of times the upper black liquor is collected in step 1 is 2 to 5 times; preferably 3 to 4 times.

[0033] Further specifying, the preparation method of polystyrene microspheres in step 2 is an improved dispersion polymerization method, specifically including the following steps: S1. Add PVP powder to the ethanol solution and stir thoroughly until homogeneous; S2. Add styrene to the solution prepared in step S1 and stir thoroughly until homogeneous; S3. Add AIBN powder to the solution prepared in step S2 and stir thoroughly until homogeneous; S4. The solution prepared in step S3 is heated at a constant temperature under a protective gas atmosphere and stirred thoroughly. S5. Centrifuge the solution prepared in step S4 to obtain a precipitate; S6. Wash the precipitate prepared in S5 with an appropriate amount of ethanol solution multiple times, centrifuge, and finally collect the precipitate. S7. The precipitate collected in S6 is heated and dried to collect the powder, which is polystyrene microsphere powder.

[0034] Furthermore, the mass fraction of the ethanol solution used in step S1 is 87%-91%; preferably 89%-90%.

[0035] Furthermore, the weight-average molecular weight (Mw) of the PVP powder used in step S1 is 58,000.

[0036] Furthermore, the mass ratio of PVP powder to ethanol solution used in step S1 is 1:30~40; preferably 1:35~40.

[0037] Furthermore, the stirring time in step S1 is 5 to 20 minutes; preferably 10 to 15 minutes.

[0038] Furthermore, the styrene used in step S2 has a purity of 99% or higher.

[0039] Furthermore, the mass ratio of styrene to PVP powder used in step S2 is 10~12:1; preferably 11~11.5:1.

[0040] Furthermore, the stirring time in step S2 is 5 to 30 minutes; preferably 10 to 20 minutes.

[0041] Furthermore, the purity of the AIBN powder used in step S3 is greater than or equal to 98%.

[0042] Furthermore, the mass ratio of AIBN powder to PVP powder used in step S3 is 1:8~12; preferably 1:8~10.

[0043] Furthermore, the stirring time in step S3 is 5 to 30 minutes; preferably 10 to 20 minutes.

[0044] Furthermore, the protective gas in step S4 is either nitrogen or argon; nitrogen is preferred.

[0045] Furthermore, the constant temperature heating in step S4 is 60~75 ℃; preferably 68~72 ℃.

[0046] Furthermore, the heating and stirring time in step S4 is 20-30 h; preferably 24-26 h.

[0047] Furthermore, the centrifugation speed in step S5 is 4000~6000 rpm; preferably 4500~5000 rpm.

[0048] Furthermore, the centrifugation time in step S5 is 5 to 15 minutes; preferably 5 to 10 minutes.

[0049] Furthermore, the mass fraction of the ethanol solution used in step S6 is 10% to 30%; preferably 20% to 25%.

[0050] Furthermore, the mass ratio of ethanol solution to precipitate used in step S6 is 15~25:1; preferably 15~20:1.

[0051] Furthermore, the centrifugation speed in step S6 is 4000~6000 rpm; preferably 4500~5000 rpm.

[0052] Furthermore, the centrifugation time in step S6 is 5 to 15 minutes; preferably 5 to 10 minutes.

[0053] Furthermore, the number of centrifugation cycles in step S6 is 2 to 5 times; preferably 3 to 4 times.

[0054] Furthermore, the precipitation heating and drying temperature in step S7 is 40~50 ℃; preferably 40~45 ℃.

[0055] Furthermore, the precipitate heating and drying time in step S7 is 3~6 h; preferably 3~5 h.

[0056] To further define the process, the surface modification of polystyrene microspheres in step 2 specifically includes the following steps: S21: Take an appropriate amount of ethanol solution, add polystyrene microspheres, and stir thoroughly to obtain a polystyrene microsphere ethanol solution; S22: Take an appropriate amount of ethanol solution, add a strong cationic polyelectrolyte solution, and stir thoroughly to obtain a surface modifier solution; S23: Slowly pour the surface modifier solution prepared in step S22 into the polystyrene microsphere ethanol solution prepared in S21, and stir thoroughly until homogeneous; S24: Centrifuge the solution prepared in S23 and collect the precipitate; S25: Use an appropriate amount of ethanol solution to wash the precipitate collected in step S24 multiple times with alcohol and centrifuge, collect the precipitate, which is the surface-modified polystyrene microsphere precipitate.

[0057] Furthermore, the mass fraction of the ethanol solution used in step S21 is 10% to 30%; preferably 20% to 25%.

[0058] Furthermore, the mass ratio of the ethanol solution to the polystyrene microspheres used in step S21 is 1000~2000:1; preferably 1500~2000:1.

[0059] Furthermore, the stirring time in step S21 is 5 to 20 minutes; preferably 10 to 15 minutes.

[0060] Furthermore, the mass fraction of the ethanol solution used in step S22 is 10% to 30%; preferably 20% to 25%.

[0061] Furthermore, in step S22, the mass ratio of ethanol solution to strong cationic polyelectrolyte solution is 1000~2000:1; preferably 1500~2000:1.

[0062] Furthermore, the strong cationic polyelectrolyte solution used in step S22 is a polydienedimethylammonium chloride solution with a concentration of 20 wt%.

[0063] Furthermore, the mass ratio of the strong cationic polyelectrolyte solution used in step S22 to the polystyrene microspheres used in step S31 is 1:1 to 1.2; preferably 1:1.

[0064] Furthermore, the stirring time in step S22 is 5 to 20 minutes; preferably 10 to 15 minutes.

[0065] Furthermore, in step S23, the mass ratio of the surface modifier solution to the polystyrene microsphere ethanol solution is 1:1 to 1.2; preferably 1:1 to 1.

[0066] Furthermore, the stirring time in step S23 is 0.5 to 2 hours; preferably 1 to 1.5 hours.

[0067] Furthermore, the centrifugation speed in step S24 is 4000~6000 rpm; preferably 4500~5000 rpm.

[0068] Furthermore, the centrifugation time in step S24 is 5 to 15 minutes; preferably 5 to 10 minutes.

[0069] Furthermore, the mass fraction of the ethanol solution used in step S25 is 10% to 30%; preferably 20% to 25%.

[0070] Furthermore, in step S25, the mass ratio of the precipitate to the ethanol solution is 1:100~400; preferably 1:150~300.

[0071] Furthermore, the number of alcohol washings in step S25 is 2 to 5 times; preferably 3 to 4 times.

[0072] Furthermore, the centrifugation speed in step S25 is 4000~6000 rpm; preferably 4500~5000 rpm.

[0073] Furthermore, the centrifugation time in step S25 is 5 to 15 minutes; preferably 5 to 10 minutes.

[0074] Further specifying, the concentration of the MXene colloidal solution used in step 3 is 8~15 mg / mL; preferably, the concentration of the MXene colloidal solution used in step S41 is 10 mg / mL.

[0075] Further specifying, the mass ratio of MXene colloidal solution to deionized water used in step 3 is 1:40~60; preferably 1:40~50.

[0076] Further specifying, the first stirring time in step 3 is 5~10 min; preferably 5~8 min.

[0077] Further specifying, the mass ratio of the MXene colloidal solution used in step 3 to the polystyrene microspheres used in step S21 is 50~200:1; preferably 100~150:1.

[0078] Further specifying, the second stirring time in step 3 is 2~4 h; preferably 2~3 h.

[0079] Further specifying, the filter membrane material used in step 3 is a mixed cellulose, polypropylene, or polytetrafluoroethylene; preferably a mixed cellulose.

[0080] Further specifying, the pore size of the filter membrane used in step 3 is 200~450 nm; preferably 220 nm.

[0081] Further specifying, the vacuum filtration time in step 3 is 2~12 h; preferably 6~8 h.

[0082] Further specifying, the vacuum drying temperature in step 3 is 25~45 ℃; preferably 30~40 ℃.

[0083] Further specifying, the vacuum drying time in step 3 is 2~6 h; preferably 3~4 h.

[0084] Another object of the present invention is to provide a polystyrene microsphere-based flexible pressure sensing material with enhanced sensitivity prepared by any of the above methods.

[0085] In addition, the use of polystyrene microsphere-enhanced MXene-based flexible pressure sensing materials prepared by any of the above methods is also provided, for the preparation of flexible pressure sensors for equipment pressure detection or human health monitoring.

[0086] This invention uses MXene, a material with excellent piezoresistive properties, as a substrate and prepares a polystyrene-based flexible pressure sensing material enhanced with polystyrene microspheres by introducing modified microspherical polystyrene material. First, the surface of the polystyrene microspheres modified with a strong cationic polyelectrolyte solution exhibits positive charge, allowing for simple electrostatic assembly with MXene nanosheets to form a stable composite film. Second, thanks to the introduction of polystyrene microspheres, while ensuring the overall stability of the composite material, the stress within the structure is more concentrated, thereby significantly improving the pressure sensing performance.

[0087] Compared with the prior art, the present invention has the following beneficial effects: The polystyrene microsphere-enhanced MXene-based flexible pressure sensing material prepared by this invention exhibits superior flexible pressure sensing performance. Within a wide pressure range of 0-20 kPa, the dynamic response reaches a maximum of over 835 (at 20 kPa), and the sensitivity reaches a maximum of 57.89 kPa⁻¹, representing improvements of 2826% and 1975% respectively compared to pure MXene material. This indicates that the polystyrene microspheres significantly enhance the flexible pressure sensing performance of the MXene material.

[0088] The polystyrene microsphere-enhanced MXene-based flexible pressure sensing material provided by this invention has a simple preparation process. It incorporates equipment such as a magnetic stirring heating oil bath, centrifuge, and drying oven, resulting in a high degree of automation and facilitating production and promotion.

[0089] The polystyrene microsphere-based MXene-based flexible pressure sensing material provided by this invention is suitable for small and medium-sized equipment. It can achieve high-sensitivity pressure detection without significantly increasing the equipment load. It can also be applied to human health or humanoid robot monitoring to sense activities such as heartbeat, swallowing, and bending.

[0090] For a deeper understanding of the features and technical content of this invention, please refer to the accompanying detailed description and drawings. It should be noted that the drawings are provided for illustrative purposes only and are not intended to limit the scope of the invention. Attached Figure Description

[0091] Figure 1 This is a schematic diagram of the process for preparing the polystyrene microsphere-enhanced MXene-based flexible pressure sensing material according to the present invention; Figure 2 This is a comparison diagram of the Zeta potentials of the polystyrene microspheres prepared in Example 1 before and after surface modification; Figure 3 SEM and TEM images of the polystyrene microsphere-enhanced MXene-based flexible pressure sensing material prepared in Example 1; Figure 4 Here is a schematic diagram and simulation mechanism diagram of the polystyrene microsphere-enhanced MXene-based flexible pressure sensing material prepared in Example 1; Figure 5 This is a schematic diagram of the flexible pressure sensor based on polystyrene microsphere-enhanced MXene material prepared according to the present invention and the sensing process.

[0092] Figure 6 This is a comparison chart of the pressure sensitivity of the polystyrene microsphere-enhanced MXene-based flexible pressure sensing materials prepared in Example 1 and the comparative example.

[0093] Figure 7 The graph shows the response and recovery time of the polystyrene microsphere-sensitized MXene-based flexible pressure sensing material prepared in Example 1. Detailed Implementation

[0094] The present invention will be described in detail below with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but should not be considered as limiting the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0095] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0096] Example 1: like Figure 1 As shown, the preparation of the polystyrene microsphere-enhanced MXene-based flexible pressure sensing material in this embodiment is carried out according to the following steps: S1: 4.8 g of lithium fluoride powder with a purity of 99% (AR) was poured into the lining of a reactor containing 60 mL of 9 mol / L dilute hydrochloric acid solution and stirred for 2 h under oil bath heating at 35 ℃.

[0097] S2: Add 3 g of Ti3AlC2 powder to the solution prepared in step S1 and stir for 48 h under oil bath heating at 35 ℃.

[0098] S3: Pour the solution prepared in step S2 into a centrifuge tube, centrifuge at 5000 rpm for 5 min, and collect the precipitate.

[0099] S4: Pour the precipitate collected in S3 into 60 mL of 2.5 mol / L dilute sulfuric acid solution and stir for 1 h.

[0100] S5: Pour the solution prepared in step S4 into two centrifuge tubes, shake by hand for 5 minutes, then place them in a centrifuge and centrifuge at 5000 rpm for 5 minutes. Discard the supernatant.

[0101] S6: Add about 30 mL of deionized water to each of the two centrifuge tubes containing the precipitate from S5, shake by hand for 5 min, centrifuge at 5000 rpm for 5 min, discard the supernatant, repeat 3 times, the pH of the supernatant is 7, discard the supernatant from the last time.

[0102] S7: Combine the precipitates from the two centrifuge tubes in S6 into one centrifuge tube, add 20 mL of deionized water, shake by hand for 5 min, centrifuge at 5000 rpm for 5 min, collect the upper black liquid, repeat three times to obtain MXene colloidal solution with a concentration of 10 mg / mL.

[0103] S8: Add 1.8 g of PVP to a three-necked flask containing 70 g of 20 wt% ethanol solution and stir for 15 min; then add 20 g of styrene and stir for 10 min; then add 0.2 g of AIBN powder and stir for 10 min.

[0104] S9: Heat and stir the S8 solution in a nitrogen atmosphere and an oil bath at 70 °C for 24 h.

[0105] S10: Take out the S9 solution, pour it into a centrifuge tube, centrifuge at 5000 rpm for 5 min, and discard the supernatant. Add 20 mL of 20 wt% ethanol solution to the precipitate, shake well, centrifuge at 5000 rpm for 5 min, discard the supernatant, and repeat 3 times to collect the precipitate. Heat and dry the precipitate at 45 ℃ for 4 h, and collect the powder, which is the polystyrene microsphere powder.

[0106] S11: Prepare two 30 g portions of 20 wt% ethanol solution. Add 20 mg of polystyrene microspheres to one portion to form the polystyrene microsphere ethanol solution; add 20 mg of 20 wt% polydimethylammonium chloride solution to the other portion to form the surface modifier solution. Stir each solution for 15 min. Slowly pour the surface modifier solution into the polystyrene microsphere ethanol solution and stir for 1 h.

[0107] S12: Pour the solution prepared in step S11 into a centrifuge tube, centrifuge at 5000 rpm for 5 min, and discard the supernatant. Add 20 mL of 20 wt% ethanol solution to the precipitate, shake well, centrifuge at 5000 rpm for 5 min, discard the supernatant, repeat 3 times, and collect the precipitate.

[0108] S13: Dissolve 2 mL of 10 mg / mL MXene colloidal solution in 100 mL of deionized water and stir for 5 min.

[0109] S14: Add the precipitate collected in step S12 to the solution in step S13 and stir for 2.5 h.

[0110] S15: The solution prepared in S14 was vacuum filtered using a mixed cellulose membrane with a pore size of 220 nm for 8 h to prepare a thin film.

[0111] S16: The membrane filtered in S15 is placed in a vacuum drying oven and heated at 40 ℃ for 3 h to obtain a polystyrene microsphere-enhanced MXene-based flexible pressure sensing material.

[0112] S17: Assemble the polystyrene microsphere-sensitized MXene-based flexible pressure sensing material obtained in step S16 into the following configuration: Figure 5 The flexible pressure sensor shown was tested using a Shanghai Chenhua Chi760E electrochemical workstation, and the results were obtained. Figure 6 and Figure 7 The performance of the flexible pressure sensor is shown.

[0113] Comparative example: The difference between this comparative example and the embodiment is that steps S8 to S12 and steps S14 to S16 are no longer performed. The solution prepared in step S13 is directly filtered and dried to produce a thin film and test it. The remaining process steps and parameter settings are the same as those in the embodiment.

[0114] Figure 2 The comparison of the Zeta potential before and after surface modification of PS microspheres is shown. As shown in the figure, the surface Zeta potential of pure polystyrene microspheres is -11.57 mV; after modification with polydimethylammonium chloride solution, the surface Zeta potential of the modified polystyrene microspheres is +10.63 mV. This fully demonstrates that after surface modification, the surface of polystyrene microspheres changes from electronegative (Zeta < 0) to electronegative (Zeta > 0), laying the foundation for subsequent composites of modified polystyrene microspheres with electronegative MXene nanosheets.

[0115] Figure 3 SEM and TEM images of a polystyrene microsphere-enhanced MXene-based flexible pressure sensing material are shown. From Figure 3 As can be clearly seen, after composite processing, polystyrene microspheres are distributed between MXene nanosheets. This not only avoids the stacking problem of MXene nanosheets but also improves the internal microstructure of MXene nanosheets, laying a structural foundation for enhancing flexible pressure sensing performance.

[0116] Figure 4 A schematic diagram and simulation mechanism diagram of the polystyrene microsphere-enhanced MXene-based flexible pressure sensing material are shown. As shown in the figure, the prepared polystyrene microsphere-enhanced MXene-based flexible pressure sensing film has good flexibility and can maintain its morphology after bending. Figure 4 The schematic diagram on the left vividly illustrates the internal microstructure of the polystyrene microsphere-enhanced MXene-based flexible pressure sensing material. Figure 4 The simulation diagram on the right shows that when the composite film is subjected to external pressure, it can not only maintain the stability of the overall structure of the film, but also adjust the stress distribution inside the film, achieve stress concentration, and thus improve the pressure sensitivity.

[0117] Figure 5 This paper illustrates the flexible pressure sensor based on polystyrene microsphere-enhanced MXene material prepared according to this invention, and a schematic diagram of the sensing process. The polystyrene microsphere-enhanced MXene material prepared according to this invention was selected as the flexible pressure sensing material. A flexible pressure sensor was fabricated by combining a flexible PET substrate and copper electrodes to complete subsequent sensing performance testing. The schematic diagram vividly illustrates the internal changes of the material during the sensing of external pressure.

[0118] Figure 6This study compares the flexible pressure sensing performance of polystyrene microsphere-enhanced MXene-based flexible pressure sensing materials with that of pure MXene materials. As shown in the figure, within a wide pressure range of 0-20 kPa, the dynamic response reaches a maximum of over 835 (at a pressure of 20 kPa), and the sensitivity reaches a maximum of 57.89 kPa⁻¹, representing improvements of 2826% and 1975% respectively compared to pure MXene materials. This demonstrates that polystyrene microspheres significantly enhance the flexible pressure sensing performance of MXene materials.

[0119] Figure 7 The response and recovery times of the polystyrene microsphere-enhanced MXene-based flexible pressure sensing material were demonstrated to be 46.9 ms and 49.8 ms, respectively, showing rapid pressure sensing response performance.

[0120] The specific embodiments of the present invention have been described in detail above. It should be noted that the present invention is not limited to the specific embodiments described above. Various modifications or alterations can be made by those skilled in the art without departing from the scope of protection defined by the claims, and all such modifications or alterations fall within the scope of the present invention.

Claims

1. A method for preparing a polystyrene microsphere-enhanced MXene-based flexible pressure sensing material, characterized in that, Includes the following steps: Step 1: Pour lithium fluoride powder into dilute hydrochloric acid, stir under constant temperature heating until uniform, add MAX phase powder, stir under constant temperature heating to react, centrifuge, collect the precipitate, pour the precipitate into dilute sulfuric acid, stir, centrifuge and take the precipitate, wash with deionized water several times and centrifuge until neutral, collect the upper black liquor to obtain MXene colloidal solution. Step 2: Using a strong cationic polyelectrolyte, the surface of polystyrene microspheres is modified by electrostatic self-assembly technology to obtain surface-modified polystyrene microspheres; Step 3: Take an appropriate amount of MXene colloidal solution, add deionized water to dilute it, stir thoroughly to obtain MXene dispersion, then add modified polystyrene microspheres to MXene dispersion, stir until uniform, load onto the filter membrane surface by vacuum filtration, and vacuum dry to obtain the flexible pressure sensing material.

2. The method according to claim 1, characterized in that, The concentration of the MXene colloidal solution is 8~15 mg / mL, and the mass ratio of MXene colloidal solution, strong cationic polyelectrolyte, and polystyrene microspheres is (100~150):1:

1.

3. The method according to claim 1, characterized in that, The strong cationic polyelectrolyte is polydienedimethylammonium chloride.

4. The method according to claim 1, characterized in that, Polystyrene microspheres are prepared according to the following method: PVP powder was added to the ethanol solution and stirred thoroughly. Styrene was added and stirred thoroughly. AIBN powder was added and stirred thoroughly. The mixture was heated at a constant temperature under a protective gas atmosphere with stirring. The mixture was then centrifuged. The precipitate was washed with alcohol and centrifuged multiple times. The precipitate was collected, dried, and polystyrene microspheres were obtained.

5. The method according to claim 4, characterized in that, The ethanol solution has a mass fraction of 87%-91%, the mass ratio of PVP powder to ethanol solution is 1:30-40, the mass ratio of styrene to PVP powder is 10-12:1, the mass ratio of AIBN powder to PVP powder is 1:8-12, and it is heated at a constant temperature of 60 ℃-75 ℃.

6. The method according to claim 1, characterized in that, Step 2 involves the following modifications: Polystyrene microspheres were added to the ethanol solution and stirred thoroughly to obtain a polystyrene microsphere ethanol solution. Add a strong cationic polyelectrolyte solution to an ethanol solution and stir thoroughly to obtain a surface modifier solution; Slowly pour the surface modifier solution into the polystyrene microsphere ethanol solution, stir thoroughly, centrifuge, collect the precipitate, and repeat the alcohol washing and centrifugation process several times to collect the precipitate.

7. The method according to claim 1, characterized in that, The filter membrane is made of a mixture of cellulose, polypropylene, or polytetrafluoroethylene.

8. The method according to claim 1, characterized in that, The pore size of the filter membrane is 200~450 nm.

9. A polystyrene microsphere-enhanced MXene-based flexible pressure sensing material prepared by the method of any one of claims 1-8.

10. An application of the polystyrene microsphere-sensitized MXene-based flexible pressure sensing material prepared by the method of any one of claims 1-8, for the preparation of flexible pressure sensors for equipment pressure detection or human health monitoring.

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