Self-adhesive multifunctional aerogel / hydrogel composite material for plant sensing and preparation method thereof

Abstract

The invention discloses a self-adhesion multifunctional aerogel / hydrogel composite material for plant sensing and a preparation method thereof. The aerogel / hydrogel composite wetting gradient is constructed, and stable voltage output under a low-humidity condition is realized by using good adhesion and wettability of the hydrogel. Meanwhile, MXene nanosheets and MoS2 are introduced into the hydrogel to serve as components of a glucose response synergistic functional material, and synergistic perception of environment humidity and biomolecule concentration is achieved. The constructed aerogel / hydrogel composite sensing device has multiple functions of wet electricity generation, self-adhesion capability, glucose response, strain sensing and the like, and shows wide application potential in complex environment and multi-mode signal monitoring.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flexible wearable electronic devices, in particular to a self-adhesive multifunctional plant sensing aerogel / hydrogel composite material and a preparation method thereof. BACKGROUND

[0002] With the continuous progress of sustainable development and intelligent monitoring technology, wet electrogeneration as a new self-powered technology has shown great application potential in the field of flexible electronics and biosensors. Wet electrogeneration system utilizes the moisture in the environment to drive charge separation and transport, providing energy for sensors and wireless devices. However, existing wet electrogeneration materials perform poorly in low humidity environments, mainly due to their low water capture capacity and ion migration performance, which limits the generation of electrical energy, which seriously affects the application of wet electrogeneration technology in complex and variable environments. Therefore, improving the wet electrogeneration capacity of materials in low humidity conditions has become a key challenge for the widespread application of wet electrogeneration technology.

[0003] To solve the above problems, researchers have proposed a strategy of combining hydrogel with aerogel to optimize the performance of the wet electrogeneration system. Zhao et al. proposed a MENG based on MXene aerogel and polyacrylamide (PAM) organic hydrogel double-layer structure. The device utilizes the hydrophilicity and negative surface charge of MXene aerogel, as well as the excellent water retention and structural stability of PAM hydrogel, achieving continuous and stable power generation in the relative humidity range of 20% to 95%. In addition, in another study, Zhao et al. adopted a vertical structure of polymer aerogel combined with hydrogel, further improving the voltage output and wet electrogeneration performance of the material in low humidity conditions. Through this composite structure design, not only the stable output of the wet electrogeneration system in low humidity is enhanced, but also the adhesion and deformation adaptability of the aerogel on complex biological interfaces are improved, providing a new solution for the integration of wet electrogeneration and multi-modal sensor devices. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a self-adhesive multifunctional plant sensing aerogel / hydrogel composite material and a preparation method thereof to overcome the shortcomings of the prior art. The method combines electrospinning, directional freeze-drying and cyclic freeze-thaw technology, and the obtained CA / PVA / PANa / MXene / MoS2 aerogel / hydrogel composite material has special gradient wet structure, high conductivity, glucose responsiveness, tensile responsiveness and excellent wet electrogeneration performance.

[0005] To achieve the above-mentioned application purposes, the technical scheme adopted by the present application is as follows: a CA / PVA / PANa / MXene / MoS2 aerogel / hydrogel composite self-powered sensing material and a preparation method thereof, comprising the following steps:

[0006] (1) Synthetically preparing MXene nanosheets, the method comprising the following steps:

[0007] (1.1) Adding lithium fluoride into a concentrated hydrochloric acid solution and stirring until the lithium fluoride is completely dissolved;

[0008] (1.2) Slowly adding titanium aluminum carbide powder into the lithium fluoride / hydrochloric acid etching solution and stirring at 40-50°C for 20-24 hours to obtain a stable suspension;

[0009] (1.3) Washing the suspension of step (1.2) by circulating centrifugation with deionized water until the supernatant pH≥6;

[0010] (1.4) Vacuum-assisted filtering the product of step (1.3) with deionized water as the medium, and then dispersing it in deionized water and ultrasonicating in an ice bath to obtain a Ti3C2TX MAX aqueous suspension;

[0011] (1.5) Centrifuging the suspension obtained in step (1.4), collecting the suspension in a centrifuge tube, placing it in a -90 to -45°C refrigerator, and then freeze-drying to obtain MXene nanosheets.

[0012] (2) Weighing different cellulose acetate (CA) powders and dissolving them in a solvent, stirring until uniform, and storing for later use;

[0013] (3) Using electrospinning technology to prepare nanofiber membranes from the spinning solution of step (2), and then placing them in an oven for drying and storing for later use;

[0014] (4) Dissolving and dispersing the dried MXene nanosheets of step (1) in deionized water and ultrasonicating, and then using an ultrasonic crusher for further homogenization and dispersion to obtain an MXene dispersion;

[0015] (5) Adding the dried nanofiber membranes of step (3) to deionized water and homogenizing and dispersing using a homogenizer to obtain a short nanometer dispersion;

[0016] (6) Mixing the MXene dispersion of step (4) with the short nanometer dispersion of step (5) and further dispersing using an ultrasonic crusher to obtain an MXene / short nanofiber mixed dispersion;

[0017] (7) Adding polyvinyl alcohol (PVA) dropwise to the mixed dispersion of step (6), stirring until uniform, and then placing it in a -90 to -45°C refrigerator for vertical directional freezing, and then freeze-drying to obtain a cellulose acetate nanofiber composite conductive aerogel primary product.

[0018] (8) The nanofiber composite conductive aerogel obtained in step (7) is placed in a vacuum drying oven, and heated and cross-linked for 3-5 hours to obtain a nanofiber composite conductive aerogel sensing material.

[0019] (9) An MXene and molybdenum disulfide (MOS2) uniform dispersion solution is prepared by ultrasonic configuration, and PVA and sodium phytate (PANa) are added and heated and stirred until uniformly mixed.

[0020] (10) The mixed solution obtained in step (9) is subjected to freeze-thaw cycle treatment in a-80℃ refrigerator, and after being frozen for a certain period of time, it is thawed, and this cycle is repeated several times to promote the cross-linking of the hydrogel.

[0021] (11) The aerogel prepared in step (8) is combined with the hydrogel prepared in step (10) to prepare a CA / PVA / PANa / MXene / MoS2 aerogel / hydrogel composite self-powered sensing material.

[0022] Further, the concentration of hydrochloric acid in step (1.1) is 8-12 moles per liter.

[0023] Further, the time for adding titanium aluminum carbide to the lithium fluoride / hydrochloric acid etching solution in step (1.2) is controlled to be 6-12 minutes.

[0024] Further, the rotation speed for the cycle centrifugal washing in step (1.3) is 3000-4000 rmp.

[0025] Further, the filter membrane used in the vacuum-assisted filtration process in step (1.4) is a hydrophilic PVDF polyvinylidene fluoride membrane (diameter range 50-90 mm, pore size range 200-250 nm) produced by Haishan Xindong Plastic Technology Co., Ltd.

[0026] Further, the ice bath ultrasonic in step (1.4) is performed using an ultrasonic disruptor, and the ultrasonic power is 200-240 W.

[0027] Further, the freeze-drying in step (1.5) is performed at-90 to-45℃ and a pressure of 2-100 Pa, and the freeze-drying time is 24-48 hours.

[0028] Further, the mass fraction of CA in step (2) is 16wt%, and the solvent is a mixed solution of acetone and N,N-dimethylacetamide.

[0029] Further, the concentration of MXene dispersion solution in step (4) is 4-12 mg / mL, preferably 10 mg / mL.

[0030] Further, the ultrasonic time in step (4) is 20-40 minutes; the breaking power of the ultrasonic breaking instrument is 240 W, and the time is 30-40 minutes.

[0031] Further, the concentration of the CA nanofiber dispersion liquid in step (5) is 0.5 wt%, the rotation speed of the homogenizer is 12000 rmp, and the time is 10-15 minutes.

[0032] Further, the MXene dispersion liquid and the CA short nanometer dispersion liquid are mixed in a volume ratio of 1:1 in step (6).

[0033] Further, the mass ratio of PVA to CA in step (7) is 1:2.

[0034] Further, the directional freezing and freeze-drying method in step (7) is as follows: the MXene / PVA / short nanofiber mixed solution is poured into a self-made mold (wherein the bottom is a copper plate, and the periphery is a polytetrafluoroethylene tube with a diameter of 1-2 cm). The mold after pouring the solution is placed in a refrigerator at-90 to-45℃ for 20-24h. Subsequently, it is placed in a freeze dryer under the conditions of 2-100 Pa, -90 to-45℃ for continuous freeze-drying for 40-50h, and a composite conductive aerogel is preliminarily obtained.

[0035] Further, the heating crosslinking temperature in step (8) is 120-150℃.

[0036] Further, the MXene concentration in step (9) is 1-2 mg / mL, the MOS2 concentration is 0.2-0.5 mg / mL, and the PVA addition amount is 6-10 wt%.

[0037] The mass ratio of PVA to PANa is in the range of 3:1-4:1.

[0038] Further, the optimal freeze-thaw cycle number in step (9) is 2-3 times, the freezing time is 2-4h, and the thawing time is 30-90 minutes.

[0039] The present application has the beneficial technical effects of:

[0040] By constructing a multifunctional gradient structure aerogel and hydrogel composite material, not only the performance bottleneck of traditional wet electricity generation is broken through, but also a new solution is provided for the application in the fields of intelligent agriculture, environmental monitoring and biosensors. In the future, by further optimizing the sensor performance and structure design, the system is expected to be widely used in plant health monitoring and precision agriculture, and has important scientific value and practical significance.

[0041] (1) The composite hydrogel with PVA as the matrix combined with MXene and MoS2 is prepared, and the structural stability and mechanical properties are enhanced by freeze-thaw cycle method. At the same time, the hydrogel layer plays a role in continuously supplying water and effectively transmitting to the aerogel layer in the device, solving the problem of unstable voltage output in low humidity environment.

[0042] (2) The hydrogel endows the material with excellent interface adaptability and self-adhesion performance, which can be stably attached to various complex surfaces without relying on external adhesives, providing a good foundation for subsequent biological attachment and wearable applications.

[0043] (3) The device can monitor multi-modal signals such as plant mechanical deformation and glucose response in real time, and respond sensitively to plants under stress such as strong light irradiation and salt stress. The performance of the sensor in glucose detection is highly consistent with commercial instruments, showing its wide application potential in biological sensors and food detection fields. This technology provides an innovative technical path and reliable support for intelligent agriculture and plant health monitoring. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor. Among them:

[0045] Figure 1 The CA / PVA / PANa / MXene / MoS2 aerogel / hydrogel composite sensing device wet electricity generation performance comparison chart prepared for Example 1, Example 2 and Comparative Example; wherein Figure a is the voltage output comparison of fiber membrane based sensing device, aerogel based sensing device and aerogel / hydrogel composite sensing device in low humidity environment; Figure b is the voltage output of aerogel, hydrogel and aerogel / hydrogel composite material in low humidity environment; Figure c is the voltage output of the aerogel / hydrogel composite sensing device under different humidity.

[0046] Figure 2 The glucose sensing performance test chart of the CA / PVA / PANa / MXene / MoS2 aerogel / hydrogel composite sensing device prepared by using Example 2 of the present application; wherein Figure a is the glucose response sensing mechanism of the aerogel / hydrogel composite sensing device; Figure b is the glucose response comparison of PVA, PVA-MXene and PVA-MXene-MoS2 hydrogel; Figure c is the glucose response curve of different concentrations; Figure d is the glucose response fitting curve of different concentrations; Figure e is the C-V curve under different scanning rates; Figure f is the fitting curve under different scanning rates.

[0047] Figure 3 Figure is a strain sensing performance test diagram of the CA / PVA / PANa / MXene / MoS2 aerogel / hydrogel composite sensing device prepared by the embodiment 2 of the present application; wherein figure a is the resistance response curve of the sensing device under different tensile stress; figure b is the resistance response change fitting curve of the sensing device under different tensile stress; figure c is the resistance response cycle stability test under different tensile stress; figure d is the resistance response cycle stability test under different tensile rate.

[0048] Figure 4 Figure is an adhesion performance test diagram of the CA / PVA / PANa / MXene / MoS2 aerogel / hydrogel composite sensing device prepared by the embodiment 2 of the present application; wherein figure a is a real object diagram of the gas sensor adhering to the surface of different plants; figure b is the adhesion force test of the sensor adhering to different material objects.

[0049] Figure 5 Figure is an electrical signal response diagram of the CA / PVA / PANa / MXene / MoS2 aerogel / hydrogel composite sensing device testing plant glucose prepared by the embodiment 2 of the present application.

[0050] Figure 6 Figure is a resistance response diagram of the CA / PVA / PANa / MXene / MoS2 aerogel / hydrogel composite sensing device testing plant growth signal prepared by the embodiment 2 of the present application; wherein figure a is a schematic diagram of the aerogel / hydrogel composite sensing device monitoring the growth of soybean under healthy / salt stress; figure b is the resistance change curve of the growth of soybean under healthy / salt stress; figure c is the length change of the sensor attachment part of the growth of soybean under healthy / salt stress. DETAILED DESCRIPTION

[0051] In order to better understand the above-mentioned purposes, features and advantages of the present application, the specific embodiments of the present application will be described in detail below in combination with the drawings and specific embodiments.

[0052] The structures, proportions, sizes, etc. shown in the drawings of the specification are only used to cooperate with the content disclosed in the specification, to be understood and read by those skilled in the art, and do not have technical significance to limit the conditions that can be implemented by the present application. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effect and purpose that can be produced by the present application, should still fall within the scope of the technical content disclosed by the present application. Meanwhile, the terms such as "upper", "lower", "front", "rear", "middle" etc. cited in the specification are only for the convenience of clear description, and are not used to limit the scope of the present application. The change or adjustment of the relative relationship, without substantially changing the technical content, is also considered as the scope of the present application.

[0053] Second, the term "one embodiment" or "an embodiment" as may appear in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive or alternative embodiments.

[0054] Embodiment 1

[0055] The MXene / CA / PVA aerogel sensing material and a preparation method thereof, comprising the following steps:

[0056] (1) Synthetically preparing MXene nanosheets, the method comprising the following steps:

[0057] (1.1) Take 15.4 mL of 11.7 mol / L concentrated hydrochloric acid solution, add deionized water to 20 mL to prepare a 9 mol / L hydrochloric acid solution, and reserve for later use.

[0058] (1.2) Weigh 1.6 g of lithium fluoride and dissolve it in the concentrated hydrochloric acid solution described in step (1.1), stir to ensure complete dissolution of lithium fluoride, and prepare a LiF / HCl etching solution.

[0059] (1.3) Slowly add 1 g of titanium aluminum carbide powder to the LiF / HCl etching solution described in step (1.2), and magnetically stir (550 rpm) at 40°C for 24 hours to obtain a stable suspension.

[0060] (1.4) Perform cyclic centrifugal washing (3500 rpm, 5 minutes per time) on the suspension described in step (1.3) with deionized water until the supernatant pH≥6.

[0061] (1.5) Vacuum-assisted filtration (deionized water as medium, about 1 L used) of the product described in step (1.3) is performed, wherein the filter membrane is a PVDF membrane with a pore size of 220 nm, and then it is dispersed in deionized water and ultrasonically treated in an ice bath for 1 hour (240 W power) to obtain a Ti3C2TX MAX aqueous suspension.

[0062] (1.6) Centrifuge the suspension obtained in step (1.5) (3500 rpm, 5 minutes), collect the suspension in the centrifuge tube, freeze in a-80°C refrigerator, and then freeze-dry at-90°C and 2 Pa pressure for 24 hours to obtain MXene nanosheets.

[0063] (2) Weigh 3.2 g of CA powder and dissolve it in 16.8 g of a mixed solution of acetone and N,N-dimethylacetamide, stir to dissolve thoroughly, and prepare a 16 wt% CA spinning solution, and reserve for later use.

[0064] (3) The CA spinning solution of step (2) is spun in a high-voltage electrostatic field with a voltage of 20 kV, wherein the distance from the needle tip to the receiving roller is 20 cm, the pushing speed of the spinning solution is 1 mL / h, and a non-woven fabric is selected as the receiving material. The ambient temperature is 25±2°C, and the relative humidity is maintained at 60±5%. After collecting the CA nanofiber membrane, it is placed in a 50°C drying oven for 24 hours.

[0065] (4) 200 mg of the dried MXene nanosheet of step (1) is dissolved and dispersed in 20 mL of deionized water and ultrasonicated for 30 minutes, and then further homogenously dispersed using an ultrasonic crusher (240 W power, 30 minutes) to obtain a MXene dispersion;

[0066] (5) 0.1 g of the dried CA nanofiber membrane of step (3) is cut into small pieces (1*1 cm) and added to 10 mL of deionized water, and then homogenized at 12000 rpm for 15 minutes using a homogenizer to obtain a CA short nanodispersion;

[0067] (6) The MXene dispersion of step (4) and the CA short nanodispersion of step (5) are mixed, and further dispersed using an ultrasonic crusher (240 W power, 30 minutes) to obtain a CA-MXene mixed dispersion;

[0068] (7) 50 mg of PVA is added dropwise to the mixed dispersion of step (6), stirred uniformly, and then transferred to a self-made mold, and placed in a -80°C refrigerator for 24 h. Subsequently, it is placed in a freeze dryer under the conditions of 2-100 Pa and -90°C for continuous freeze-drying for 48 h, and a composite conductive aerogel is obtained.

[0069] (8) The composite conductive aerogel of step (7) is placed in a vacuum drying oven, heated and crosslinked at 145°C for 3 hours to obtain a CA / MXene / PVA composite conductive aerogel sensing material.

[0070] Example 2

[0071] A CA / PVA / PANa / MXene / MoS2 aerogel / hydrogel composite self-powered sensing material and a preparation method thereof:

[0072] (1) MXene nanosheets are synthesized and prepared according to the method of step (1) in Example 1.

[0073] (2) 3.2 g of CA powder is dissolved in 16.8 g of a mixed solution of acetone and N,N-dimethylacetamide, thoroughly stirred and dissolved, and configured into a 16wt% CA spinning solution, which is uniformly stirred and stored for use.

[0074] (3) The CA spinning solution described in step (2) is spun in a high-voltage electrostatic field with a voltage of 20 kV, wherein the distance from the needle tip to the receiving roller is 20 cm, the pushing speed of the spinning solution is 1 mL / h, and a non-woven fabric is selected as the receiving material. The ambient temperature is 25±2°C, and the relative humidity is maintained at 60±5%. After collecting the CA nanofiber membrane, it is placed in a 50°C drying oven for 24 hours.

[0075] (4) 200 mg of the dried MXene nanosheet solution described in step (1) is dissolved and dispersed in 20 mL of deionized water and ultrasonicated for 30 minutes, followed by further homogenization dispersion using an ultrasonic crusher (240 W power, 30 minutes) to prepare a MXene dispersion liquid;

[0076] (5) 0.1 g of the dried CA nanofiber membrane described in step (3) is cut into small pieces (1*1 cm) and added to 10 mL of deionized water, and a homogenizer is used to homogenize at 12000 rpm for 15 minutes to prepare a CA short nanodispersion liquid;

[0077] (6) The MXene dispersion liquid and the CA short nanodispersion liquid described in steps (4) and (5) are mixed, and further dispersed using an ultrasonic crusher (240 W power, 30 minutes) to prepare a CA-MXene mixed dispersion liquid;

[0078] (7) 50 mg of PVA is added dropwise to the mixed dispersion liquid described in step (6), stirred uniformly, and then transferred to a self-made mold, and placed in a -80°C refrigerator for 24 h. Subsequently, it is placed in a freeze dryer under the conditions of 2-100 Pa and -90°C for continuous freeze-drying for 48 h, and a preliminary composite conductive aerogel is obtained.

[0079] (8) The composite conductive aerogel described in step (7) is placed in a vacuum drying oven, heated and crosslinked at 145°C for 3 hours to obtain a CA / MXene / PVA composite conductive aerogel sensing material.

[0080] (9) A uniform dispersion liquid with a concentration of 1 mg / mL of MXene and a concentration of 0.5 mg / mL of MOS2 is prepared by ultrasonic configuration, and PVA and PANa are added and heated and stirred until uniformly mixed.

[0081] (10) The mixed solution described in step (9) is subjected to freeze-thaw cycle treatment in a -80°C refrigerator, and after freezing for a certain time at low temperature, it is thawed, and this cycle is repeated twice, thereby promoting the crosslinking of the hydrogel to form.

[0082] (11) The aerogel prepared in step (8) is combined with the hydrogel prepared in step (10) to prepare a CA / PVA / PANa / MXene / MoS2 aerogel / hydrogel composite self-powered sensing material.

[0083] Comparative Example:

[0084] The sensing material, which is consistent with the raw materials and preparation parameters used in Example 2 but does not composite the aerogel and hydrogel material, is compared with the material of the application in structure and performance, including the following steps:

[0085] (1) Synthesis and preparation of MXene nanosheets, the method is consistent with step (1) in Example 1.

[0086] (2) Prepare a uniform dispersion of MXene with a concentration of 1 mg / mL and MOS2 with a concentration of 0.5 mg / mL by ultrasonic, then add PVA and PANa and heat and stir until mixed evenly.

[0087] (3) The mixed solution described in step (2) is subjected to freeze-thaw cycle treatment in a -80°C refrigerator, and after freezing for a certain time at low temperature, it is thawed, and the cycle is repeated twice, thereby preparing a hydrogel layer conductive sensing material.

[0088] Test Example:

[0089] Humid electrogeneration performance test: record the parameters of the aerogel / hydrogel composite sensing device prepared in Examples 1-2 and Comparative Example, then use a static electricity meter (model 6514, KEITHLEY, USA) to place the prepared sensor in a sealed glass container, and connect it to the static electricity meter through alligator clips. The humidity flow of different humidity is provided by a self-made moisture circulation humidity control system. The environmental humidity is controlled by adjusting the ratio of humid nitrogen (water vapor) flow and dry nitrogen flow, and the relative humidity is monitored by a hygrometer.

[0090] Glucose sensing performance test: use an electrochemical workstation (model CHI660E, Shanghai Chenhua Company) to test the glucose response performance. Assemble the CA / PVA / PANa / MXene / MoS2 aerogel / hydrogel composite sensing device prepared in Example 2 with conductive fabric, etc. to prepare a simple device, clamp the two ends of the device with alligator clips and connect them to the electrochemical workstation, and use a three-electrode system to test the cyclic voltammetry curve.

[0091] Tensile sensing performance test: use a precision digital bridge (model TH2830, Changzhou Tonghui Electronics Co., Ltd.) combined with a universal testing machine to test the tensile strain sensing performance. Assemble the CA / PVA / PANa / MXene / MoS2 aerogel / hydrogel composite sensing device prepared in Example 2 with conductive fabric, etc. to prepare a simple device, clamp the two ends of the device with alligator clips and connect them to the digital bridge, and observe and record the changes in conductivity and resistance response of the material.

[0092] It should be noted that the above examples are only used to illustrate the technical solutions of the present application but not to limit the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that there are still many improvements and modifications that can be made without departing from the spirit and scope of the technical solutions of the present application, and all these improvements and modifications should be encompassed in the scope of the claims of the present application.

Claims

1. A self-adhesive multifunctional plant sensing aerogel / hydrogel composite material and a method for preparing the same, characterized by, The preparation method comprises the following steps: (1) Synthesis of MXene nanosheets: lithium fluoride is slowly added to a concentrated hydrochloric acid solution and stirred uniformly, aluminum carbide powder is slowly added thereto, and stirring is performed at 40-50°C for 20-24 hours to obtain a suspension, the suspension is subjected to cyclic centrifugal washing (until the supernatant pH is greater than or equal to 6), then the precipitate is subjected to vacuum-assisted filtration and dispersed in deionized water for ultrasonic treatment, the suspension is collected after centrifugation, and is frozen and freeze-dried to obtain MXene nanosheets, which are stored for later use; (2) Cellulose acetate powder is weighed and dissolved in a corresponding solvent to obtain a uniform spinning solution, which is stored for later use; (3) The spinning solution in step (2) is prepared into a nanofiber membrane by using an electrospinning technology, and then placed in an oven for drying, which is stored for later use; (4) The dried MXene nanosheets in step (1) are dissolved and dispersed in deionized water and subjected to ultrasonic treatment, and then subjected to further homogeneous dispersion by using an ultrasonic crusher to obtain a MXene dispersion liquid; (5) The dried nanofiber membrane in step (3) is added to deionized water, and subjected to homogeneous dispersion by using a homogenizer to obtain a short nanometer dispersion liquid; (6) The MXene dispersion liquid in step (4) is mixed with the short nanometer dispersion liquid in step (5), and subjected to further dispersion by using an ultrasonic crusher to obtain a MXene / short nanofiber mixed dispersion liquid; (7) Polyvinyl alcohol (PVA) is added dropwise to the mixed dispersion liquid in step (6), stirred uniformly, and then placed in a refrigerator with a temperature range of -90 to -45°C for vertical directional freezing, and then freeze-dried to obtain a cellulose acetate nanofiber composite conductive aerogel primary product. (8) The nanofiber composite conductive aerogel in step (7) is placed in a vacuum drying oven, heated and crosslinked for 3-5 hours to obtain a nanofiber composite conductive aerogel sensing material. (9) The MXene and MOS2 uniform dispersion liquid is configured by ultrasonic, and PVA and PAN are added a Post-heating stirring until mixed evenly. (10) The mixed solution in step (9) is subjected to freeze-thaw cycle treatment in a -80°C refrigerator, and after being frozen for a certain period of time at low temperature, it is thawed, and this cycle is repeated for multiple times, so as to promote the crosslinking of the hydrogel. (11) The aerogel prepared in step (8) is combined with the hydrogel prepared in step (10) to prepare a CA / PVA / PANa / MXene / MoS2 aerogel / hydrogel composite self-powered sensing material.

2. The production method according to claim 1, characterized by, In step (1), the concentration of the hydrochloric acid is 8-12 moles per liter, the time for adding titanium aluminum carbide to the lithium fluoride / hydrochloric acid etching solution is controlled to be 6-12 minutes, the centrifugal washing speed of the suspension is 3000-4000 rpm, the filter membrane used for vacuum-assisted filtration is a hydrophilic PVDF polyvinylidene fluoride membrane (diameter range: 50-90 mm, pore size range: 200-250 am) produced by Haishan Xindongfang Plastic Technology Co., Ltd., and the freeze-drying is performed at -90 to -45°C and a pressure of 2-100 Pa, and the freeze-drying time is 24-48 hours.

3. The preparation method according to claim 1, characterized in that, The concentration of the MXene dispersion liquid in step (4) is 4-12 mg / mL; the ultrasonic time of MXene is 20-40 minutes; the crushing power of the ultrasonic crusher is 200-240 W, and the time is 30-40 minutes.

4. The preparation method according to claim 1, characterized in that, The concentration of the CA nanodispersion liquid in step (6) is 0.3-0.6 wt%, the rotation speed of the homogenizer is 10,000-12,000 rpm, and the time is 10-15 minutes.

5. The preparation method according to claim 1, characterized in that, In step (7), the MXene dispersion liquid and the short nanodispersion liquid are mixed in a volume ratio range of 1:1-2:

1.

6. The method of claim 1, wherein, In step (8), the mass ratio of PVA to CA is in the range of 1:1-1:

2.

7. The preparation method according to claim 1, characterized in that, In step (7), the directional freezing and freeze-drying method is as follows: the MXene / PVA / short nanofiber mixed solution is poured into a self-made mold (wherein the bottom is a copper plate, and the four sides are polytetrafluoroethylene tubes with a diameter of 1-2 cm). The mold after pouring the solution is placed in a refrigerator at -90 to -45°C for 20-24 h. Subsequently, it is placed in a freeze dryer under the conditions of 2-100 Pa, -90 to -45, and continuously freeze-dried for 40-50 h, and a composite conductive aerogel is preliminarily obtained.

8. The method of claim 1, wherein, The heating crosslinking temperature in step (8) is in the range of 120-150°C.

9. The preparation method according to claim 1, in step (9), the concentration of MXene is 1-2 mg / mL, the concentration of MOS2 is 0.2-0.5 mg / mL, the addition amount of PVA is 6-10 wt%, and the mass ratio of PVA to PANa is in the range of 3:1-4:

1.

10. The preparation method according to claim 1, in step (9), the optimal freeze-thaw cycle number is 2-3 times, the freezing time is 2-4 h, and the thawing time is 30-90 minutes.

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