High-sensitivity pressure sensing aerogel material and preparation method thereof

Abstract

The application relates to the technical field of pressure-sensing aerogel materials, and discloses a high-sensitivity pressure-sensing aerogel material and a preparation method thereof.The method comprises the following steps: adding a high-molecular polymer into a solvent to prepare a prepared liquid A; adding cellulose nanofiber gel and functionalized carbon nanotubes into the prepared liquid A to disperse and obtain a prepared liquid B; diluting MXene stock solution to obtain a prepared liquid C; adding the prepared liquid C into the prepared liquid B, and alternately performing magnetic stirring and ultrasonic dispersion treatment to obtain a composite suspension precursor liquid; and performing directional temperature gradient freezing and freeze-drying to obtain a pressure-sensing aerogel material with a directional porous structure.The preparation process is simple, and no complex equipment is needed; the obtained aerogel has good structural orientation, compression resilience and pressure-sensing sensitivity, and can be applied to the field of pressure sensors such as motion and physiological signal detection.

Description

Technical Field

[0001] This invention relates to the field of gel materials technology, specifically to a highly sensitive pressure-sensing aerogel material and its preparation method. Background Technology

[0002] Pressure sensors, as crucial functional devices that convert external mechanical stimuli into electrical signals, have broad application prospects in wearable electronics, intelligent sensing systems, and other fields, particularly in monitoring human physiological signals, sensing motion states, and human-computer interaction. With the development of flexible electronics technology and intelligent wearable devices, higher demands are placed on pressure sensors in terms of sensitivity, stability, flexibility, and wearing comfort. Ideal pressure sensing materials not only need to have good response to weak pressure stimuli but should also maintain stable and repeatable signal output during repeated deformation and long-term use. However, existing pressure sensing materials still suffer from insufficient flexibility, poor wearing comfort, complex structures, or high manufacturing costs in practical applications, thus limiting their further application in the wearable field.

[0003] Aerogel materials, due to their low density, high porosity, and tunable three-dimensional porous structure, are considered a class of pressure sensing materials with promising applications. Their porous structure can undergo reversible deformation under external pressure, which is beneficial for stress transmission and signal response, thereby improving the material's pressure response performance. At the same time, aerogel materials typically possess strong structural designability and flexible fabrication methods, making them suitable for flexible and wearable pressure sensor devices. However, during repeated compression or long-term use, aerogel materials still suffer from insufficient structural stability and susceptibility to damage to the conductive network. How to improve their mechanical stability and signal reliability while maintaining high sensitivity remains a technical problem that needs to be solved in this field.

[0004] MXenes are a class of two-dimensional transition metal carbides or nitrides with high electrical conductivity, good flexibility, and abundant surface functional groups, showing great potential for application in constructing conductive aerogels and flexible sensing materials. When MXene nanosheets are assembled into a three-dimensional porous structure, they can form a conductive network, enabling the material to generate an electrical response under pressure. However, due to the relatively limited interaction forces between MXene nanosheets, they are prone to recombination during solvent removal or repeated deformation, leading to pore structure collapse and damage to conductive pathways, affecting the material's mechanical properties and sensing stability. Therefore, how to suppress MXene recombination and construct a structurally stable, conductive, and continuous porous framework is a key issue to consider in the preparation of MXene-based aerogel materials.

[0005] To improve the structural stability and overall performance of aerogel materials, researchers have attempted to construct multi-component systems by combining MXene with cellulose nanofibers, polymers, and one-dimensional conductive fillers. Cellulose nanofibers possess good flexibility and network support capabilities, providing skeletal support for the aerogel; polymers such as polyvinyl alcohol can enhance the system's bonding strength through hydrogen bonding; and one-dimensional conductive materials such as carbon nanotubes help construct multi-dimensional conductive pathways. However, the synergistic effects between different components and their influence on the microstructure and macroscopic properties of the aerogel still require further optimization. In particular, considering sensitivity, compression recovery, and long-term stability, a composite aerogel material with a simpler preparation process and controllable structure still needs to be developed.

[0006] Therefore, it is necessary to address the problems of structural stability and preparation complexity of existing pressure sensing aerogel materials, and to develop a high-sensitivity pressure sensing aerogel material and its preparation method, so as to obtain a porous aerogel material with more stable structure, more continuous conductive pathway and better flexibility, and provide a feasible material solution for applications such as pressure sensing and physiological signal detection. Summary of the Invention

[0007] To address the shortcomings of the existing technology, this invention provides a highly sensitive pressure-sensing aerogel material and its preparation method.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A method for preparing a highly sensitive pressure-sensing aerogel material includes the following steps: (1) Add the polymer to the corresponding solvent and stir continuously until it is completely dissolved to obtain a homogeneous polymer solution, which is used as prepreg A; (2) Add cellulose nanofiber gel and functionalized carbon nanotubes to the pre-prepared liquid A obtained in step (1), and mix and disperse them under magnetic stirring until a uniformly dispersed composite solution is formed to obtain pre-prepared liquid B. (3) Dilute the MXene stock solution with water and sonicate it at room temperature to obtain the pre-prepared solution C; (4) Add the pre-prepared liquid C obtained in step (3) to the pre-prepared liquid B obtained in step (2), and use alternating magnetic stirring and ultrasonic dispersion to fully mix the components and obtain a uniform composite suspension precursor liquid. (5) The composite suspension precursor liquid obtained in step (4) is frozen under a directional temperature gradient to form a frozen body with a directional pore structure. (6) The frozen body obtained in step (5) is freeze-dried to obtain a high-sensitivity pressure-sensing aerogel material.

[0009] The polymer in step (1) is at least one of polyvinyl alcohol and chitosan, and the solvent is water or a dilute acid aqueous solution.

[0010] The functionalized carbon nanotubes in step (2) are at least one of carboxylated carbon nanotubes, polydopamine-modified carbon nanotubes, or aminated carbon nanotubes.

[0011] In step (2), the mass ratio of cellulose nanofiber gel to functionalized carbon nanotubes is (400-600):(1-5).

[0012] In step (3), the concentration of MXene solution is 5-20 mg / mL, and the volume ratio of MXene stock solution to water is 1-10:1.

[0013] The mass ratio of MXene in step (3) to functionalized carbon nanotubes in step (2) is (5-15):1.

[0014] The alternating magnetic stirring and ultrasonic dispersion treatment in step (4) includes at least two magnetic stirrings and at least two ultrasonic dispersions, wherein the magnetic stirring speed is 300-500 rpm, the ultrasonic frequency is 20-40 kHz, and the treatment temperature is room temperature.

[0015] The directional temperature gradient in step (5) is achieved by placing the mold containing the composite suspension precursor liquid on a thermal bridge and setting a cold source and a heat source at both ends of the thermal bridge respectively; the cold source is liquid nitrogen and the heat source is room temperature water or a low temperature constant temperature medium.

[0016] In step (6), the temperature of the cold trap of the vacuum dryer is -100℃ to -60℃.

[0017] A highly sensitive pressure-sensing aerogel material was prepared using the method described above.

[0018] A composite aerogel material based on MXene, wherein the composite aerogel material is prepared by the above-described preparation method.

[0019] In the above-described scheme of the present invention, cellulose nanofibers possess a high aspect ratio, large specific surface area, and good flexibility, enabling them to construct a continuous and stable three-dimensional network framework in the system through fiber entanglement and interfacial interactions. Polyvinyl alcohol molecules are rich in hydroxyl groups, and chitosan is rich in hydroxyl and amino groups. After dissolving in a dilute acid medium, the molecular chains of chitosan can form hydrogen bonds and other interfacial interactions with the surface functional groups of polyvinyl alcohol, cellulose nanofibers, and MXene, thereby synergistically enhancing and regulating the flexibility of the three-dimensional framework. Functionalized carbon nanotubes, as one-dimensional conductive fillers, have surface functional groups that improve their dispersion stability in the precursor solution and enhance their interfacial bonding with cellulose nanofibers, polymers, and MXene. Functionalized carbon nanotubes act as bridges, enhancers, and conductive connections in the three-dimensional framework, facilitating the construction of a multi-dimensional conductive network composed of one-dimensional conductive pathways and two-dimensional conductive sheets. MXene nanosheets possess excellent electrical conductivity and good flexibility. Their surface is rich in functional groups, and the interfacial interactions with cellulose nanofibers, chitosan, and polyvinyl alcohol help suppress the re-aggregation of sheets during subsequent drying and improve the continuity and stability of the conductive network. During directional freezing, the introduction of a temperature gradient induces the components to align in a specific direction, forming a porous framework with an oriented structure. After freeze-drying, the ice crystal template is removed, thereby obtaining a composite aerogel material with an oriented porous structure.

[0020] The aforementioned three-dimensional porous network structure, constructed synergistically from multiple components, not only effectively suppresses the recombination behavior of MXene nanosheets during the drying process but also facilitates the formation of a continuous and stable conductive network within the aerogel. Through the skeletal support of cellulose nanofibers, the reinforcing effect of polyvinyl alcohol, and the multidimensional conductive pathways jointly constructed by carbon nanotubes and MXene, the composite aerogel material prepared in this invention can undergo reversible deformation under external pressure, accompanied by effective modulation of the conductive pathways, thereby generating a stable and repeatable electrical response, suitable for applications such as pressure sensing and physiological signal detection.

[0021] The beneficial effects of this invention are: (1) This invention utilizes the synergistic effect of cellulose nanofibers, polymers (such as polyvinyl alcohol, chitosan, etc.), carbon nanotubes and MXene, and optimizes the three-dimensional framework with polyhydroxy polymers to construct a structurally stable three-dimensional porous aerogel framework. This effectively suppresses the recombination behavior of MXene nanosheets and improves the structural stability and reliability of the material during repeated deformation.

[0022] (2) The composite aerogel material prepared by the present invention is lightweight, porous and has good compression recovery. It can produce obvious and repeatable electrical response under external pressure, and is suitable for pressure sensing and flexible sensor devices.

[0023] (3) The preparation method described in this invention has a relatively simple process flow and strong controllability, making it suitable for constructing composite aerogel materials with directional porous structures. This provides a material solution with stable performance and feasible preparation for the fields of flexible pressure sensing and physiological signal detection. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the copper bridge-Dewar flask temperature gradient freezing device used in the directional freezing process of this invention.

[0025] Figure 2 This is a scanning electron microscope image of the aerogel material prepared in Example 1 of the present invention.

[0026] Figure 3 This is a scanning electron microscope image of the aerogel material prepared in Example 2 of the present invention.

[0027] Figure 4 This is a scanning electron microscope image of the aerogel material prepared in Comparative Example 2 of the present invention.

[0028] Figure 5 This is a scanning electron microscope image of the aerogel material prepared in Comparative Example 3 of the present invention.

[0029] Figure 6 This is a scanning electron microscope energy dispersive spectroscopy (EDS) image of the aerogel material prepared in this invention.

[0030] Figure 7 This is a stress-strain curve of the aerogel material prepared in Example 1 of the present invention.

[0031] Figure 8 The current response diagram of the aerogel material prepared in Example 1 of the present invention is shown after continuous cycling for 1000s at 40% strain.

[0032] Figure 9 The current response diagram of the aerogel material prepared in Example 1 of this invention under strain of 5-80% is shown.

[0033] Figure 10 This is a graph showing the current response time and recovery time of the aerogel material prepared in Example 1 of the present invention.

[0034] Figure 11 This is a sensitivity curve data graph of the aerogel material prepared in Example 1 of the present invention.

[0035] Figure 12 The diagram shows the current response of the flexible pressure sensor constructed from the aerogel material prepared in Example 1 of this invention when detecting finger bending movements.

[0036] Figure 13The diagram shows the current response of the flexible pressure sensor constructed from the aerogel material prepared in Example 1 of this invention when detecting pulse physiological signals.

[0037] Figure 14 The diagram shows the current response of the flexible pressure sensor constructed from the aerogel material prepared in Example 1 of this invention when detecting nasal exhalation signals. Detailed Implementation

[0038] The invention will now be described in further detail with reference to specific embodiments, but it should not be construed as limiting the scope of the invention to the following embodiments.

[0039] This application describes some of the raw materials; all other raw materials not described are commercially available. Polyvinyl alcohol (PVA) has a molecular weight of 200,000 g / mol.

[0040] Chitosan, degree of deacetylation: 90%, viscosity: 50-200 mPa·s, provided by Suzhou Jiaye Biotechnology Co., Ltd.

[0041] Cellulose nanofiber gel, with a purity of ≥99% and a solid content of 1.2wt%.

[0042] Carboxylated carbon nanotubes, model XFS18, were provided by Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.

[0043] Aminated carbon nanotubes, model XFS14, were provided by Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.

[0044] The polydopamine-modified carbon nanotubes were provided by Xi'an Ruixi Biotechnology Co., Ltd.

[0045] The MXene stock solution is a commercially available aqueous dispersion provided by Jilin Yiyi Technology Co., Ltd., with a concentration of 10 mg / mL.

[0046] Example 1: A method for preparing a highly sensitive pressure-sensing aerogel material, comprising the following steps: (1) Weigh 5 mg of polyvinyl alcohol and add it to 2.0 mL of water. Heat the mixture to 95 °C under magnetic stirring at 120 rpm and continue stirring for 30 min until the polyvinyl alcohol is completely dissolved and becomes uniform and transparent. A polyvinyl alcohol solution is obtained. Weigh 2.5 mg of chitosan and add it to 1.2 mL of 1 wt% acetic acid aqueous solution. Stir the mixture at room temperature until the chitosan is fully dissolved to obtain a chitosan solution. Slowly add the chitosan solution to the polyvinyl alcohol solution and continue stirring at 300 rpm for 20 min at room temperature to mix it evenly to obtain composite pre-prepared liquid A. (2) Add 600 mg of TEMPO cellulose nanofiber gel and 3.6 mg of functionalized carbon nanotubes to the above composite prepreg A. The solid content of the TEMPO cellulose nanofiber gel is 1.2 wt%. Stir magnetically at 400 rpm for 25 min at room temperature, and then sonicate at 100 W and 25 kHz for 20 min to obtain prepreg B. The functionalized carbon nanotubes are carboxylated carbon nanotubes. (3) Take 2.4 mL of MXene stock solution with a mass concentration of 10 mg / mL, add 0.6 mL of water for dilution, and sonicate at room temperature with an ultrasonic power of 100 W and an ultrasonic frequency of 25 kHz for 40 min to obtain a uniformly dispersed MXene dispersion, i.e., pre-prepared solution C. (4) Add the pre-prepared liquid C obtained in step (3) to the pre-prepared liquid B obtained in step (2) and perform alternating dispersion treatment at room temperature. First, it is magnetically stirred at 360 rpm for 25 min, then ultrasonicated at 100 W ultrasonic power and 25 kHz ultrasonic frequency for 20 min. Then, it is magnetically stirred at 360 rpm for 25 min again, and then ultrasonicated at 100 W ultrasonic power and 25 kHz ultrasonic frequency for 20 min to obtain a uniformly dispersed composite suspension precursor liquid. (5) Pour the composite suspension precursor liquid obtained in step (4) into a silicone mold with dimensions of 2 cm × 2 cm × 2 cm, place the silicone mold on a copper bridge, the copper bridge spans between two Dewar flasks, one Dewar flask is filled with liquid nitrogen and the other Dewar flask is filled with room temperature water to form a temperature gradient at both ends of the copper bridge; under the action of this temperature gradient, the composite suspension precursor liquid is directionally frozen along the temperature gradient direction until the sample is completely frozen, and a frozen body with a directional pore structure is obtained. (6) The frozen body obtained in step (5) was placed in a cold trap at a temperature of -85°C for freeze-drying for 72 h. After the solvent was completely removed, a high-sensitivity pressure-sensing aerogel material was obtained.

[0047] Example 2: It is basically the same as Example 1, except that the mass ratio of polyvinyl alcohol and chitosan in step (1) is adjusted to 1:1.

[0048] Example 3: It is basically the same as Example 1, except that the mass ratio of polyvinyl alcohol and chitosan in step (1) is adjusted to 1:2.

[0049] Example 4: It is basically the same as Example 1, except that the functionalized carbon nanotubes in step (2) are aminated carbon nanotubes.

[0050] Example 5: It is basically the same as Example 1, except that the functionalized carbon nanotubes in step (2) are polydopamine-modified carbon nanotubes.

[0051] Comparative Example 1: It is basically the same as Example 1, except that carbon nanotubes without any functional group modification are directly added in step (2).

[0052] Comparative Example 2: Basically the same as Example 1, except that chitosan is not added in step (1): In step (1), 15 mg of polyvinyl alcohol is weighed and added to 2.0 mL of deionized water. The mixture is heated to 95°C under magnetic stirring at 120 rpm and stirred for 30 min until the polyvinyl alcohol is completely dissolved. After the system is cooled to room temperature, 1.2 mL of acetic acid aqueous solution with a mass fraction of 1 wt% is added and stirred at 300 rpm for 20 min at room temperature to make it evenly mixed and obtain pre-prepared liquid A. The remaining steps are the same as in Example 1.

[0053] Comparative Example 3: It is basically the same as Example 1, except that polyvinyl alcohol is not added in step (1): In step (1), 15 mg of chitosan is weighed and added to 1.2 mL of acetic acid aqueous solution with a mass fraction of 1 wt%, and stirred at room temperature until the chitosan is fully dissolved; then 2.0 mL of deionized water is added and stirred at 300 rpm at room temperature for 20 min to mix it evenly and obtain pre-prepared solution A. The remaining steps are the same as in Example 1.

[0054] Test Example 1: Sensitivity Test in Low Pressure Region: The pressure sensing performance of the aerogel materials prepared in Examples 1-5 and Comparative Examples 1-3 was tested. Each sample was cut into identical test samples, preferably 2.0 cm × 2.0 cm × 0.6 cm. Copper foil electrodes were attached to the upper and lower surfaces of the samples, and wires were led out using silver paste or copper conductive adhesive and connected to a digital source meter. Real-time current changes of the samples under different applied pressures were recorded under a 1 V DC bias.

[0055] The assembled sample was placed between the upper and lower pressure plates of a universal testing machine or dynamic mechanical loading platform. The pressure head was aligned with or larger than the sample's pressure area to ensure uniform force distribution. Tests were conducted at pressures of 0, 0.5, 1.0, 1.5, and 2.0 kPa; each pressure point was held for 10 seconds until the current signal stabilized. The current value was then read. Each sample group was tested in parallel at least three times, and the average value was taken. The results are shown in Table 1.

[0056] Table 1. Sensitivity test results in the low-pressure region.

[0057] As shown in Table 1, all samples exhibited a trend of gradually increasing relative current change rate with increasing pressure in the low-pressure region, indicating that the composite aerogel material prepared in this invention has relatively stable electrical response capabilities in the low-pressure range. The comparison of Examples 1-3 shows that the polyvinyl alcohol / chitosan blending ratio has a significant impact on the low-pressure response performance. A higher proportion of polyvinyl alcohol resulted in better sample sensitivity, indicating that an appropriate amount of chitosan is beneficial for enhancing interfacial interactions; however, excessive chitosan weakens the flexibility of the framework and the effective modulation of conductive paths.

[0058] The comparison of Examples 1, 4, and 5 further demonstrates that the surface groups of functionalized carbon nanotubes have a significant impact on sensing performance. Aminated carbon nanotubes and polydopamine-modified carbon nanotubes are superior to carboxylated carbon nanotubes, indicating that stronger interfacial bonding and conductive bridging are beneficial for improving low-pressure response. Comparative results show that the response performance of unfunctionalized carbon nanotubes and the single polymer system is lower than that of the composite system, indicating that the composite of polyvinyl alcohol and chitosan, as well as the surface functionalization of carbon nanotubes, contribute to the construction of a more stable three-dimensional conductive network, thereby improving the pressure sensing performance of the material.

[0059] Test Example 2: To verify the structural characterization and comprehensive performance testing of the composite aerogel material of the present invention, performance tests were conducted on the aerogel samples prepared in the examples and comparative examples. The obtained aerogel samples were approximately 2cm × 2cm × 0.6cm in size and were directly used for subsequent structural characterization and mechanical and electrical performance testing.

[0060] The microstructure of the aerogel was observed using a scanning electron microscope (SEM, Hitachi Regulus 8230) to analyze its internal porous structure and layered arrangement characteristics. The results are shown in [Figure number missing]. Figures 2 to 6 .

[0061] In the mechanical property testing, the aerogel samples were placed on a universal testing machine (ZhiQu ZQ-990L) and subjected to compression tests and cyclic compression tests at a compression rate of 150 mm / min at room temperature to obtain the stress-strain curves and cyclic stability of the material. The mechanical property test results are shown in […]. Figure 7 The results for electrical response stability, response under different strains, response recovery time, and sensitivity are shown in [reference needed]. Figure 8-11 .

[0062] In the electrical performance testing, the aerogel sample was connected to silver wires at both ends via copper conductive adhesive. The source meter's wires were then connected to a digital source meter (Keithley 2450) via the silver wires. Current changes under different pressures were recorded at 1 V DC voltage to calculate the relative current change rate and pressure sensitivity. Human motion / physiological signal detection results are shown below. Figure 12-14 .

[0063] Test results show that the composite aerogel pressure sensor has a sensitivity of up to 360 kPa in a low pressure range of 0-3000 Pa. -1 The sensitivity is approximately 80 kPa in the higher pressure range of 3000-9000 Pa. -1 It exhibits good pressure response characteristics.

[0064] Furthermore, aerogel samples were cut into small sizes of approximately 0.5 cm × 0.5 cm × 0.2 cm, connected to silver wires with copper conductive adhesive, and encapsulated with a PU film to construct a flexible pressure sensor device. This device can be used for detecting human physiological signals, such as monitoring dynamic pressure signals like finger flexion, pulse signals, and exhalation.

[0065] Experimental results show that the composite aerogel prepared by this invention has good compression resilience, stable electrical response and high pressure sensing sensitivity, and is suitable for the field of flexible pressure sensors.

Claims

1. A method for preparing a highly sensitive pressure-sensing aerogel material, characterized in that, Includes the following steps: (1) Add the polymer to the corresponding solvent and stir continuously until it is completely dissolved to obtain a homogeneous polymer solution, which is used as prepreg A; (2) Add cellulose nanofiber gel and functionalized carbon nanotubes to the pre-prepared liquid A obtained in step (1), and mix and disperse them under magnetic stirring until a uniformly dispersed composite solution is formed to obtain pre-prepared liquid B. (3) Dilute the MXene stock solution with water and sonicate it at room temperature to obtain the pre-prepared solution C; (4) Add the pre-prepared liquid C obtained in step (3) to the pre-prepared liquid B obtained in step (2), and use alternating magnetic stirring and ultrasonic dispersion to fully mix the components and obtain a uniform composite suspension precursor liquid. (5) The composite suspension precursor liquid obtained in step (4) is frozen under a directional temperature gradient to form a frozen body with a directional pore structure. (6) The frozen body obtained in step (5) is freeze-dried to obtain a high-sensitivity pressure-sensing aerogel material.

2. The method for preparing the high-sensitivity pressure-sensing aerogel material according to claim 1, characterized in that: The polymer in step (1) is at least one of polyvinyl alcohol and chitosan, and the solvent is water or a dilute acid aqueous solution.

3. The method for preparing the high-sensitivity pressure-sensing aerogel material according to claim 1, characterized in that: The functionalized carbon nanotubes in step (2) are at least one of carboxylated carbon nanotubes, polydopamine-modified carbon nanotubes, or aminated carbon nanotubes.

4. The method for preparing the high-sensitivity pressure-sensing aerogel material according to claim 1, characterized in that: In step (2), the mass ratio of cellulose nanofiber gel to functionalized carbon nanotubes is (400-600):(1-5).

5. The method for preparing the high-sensitivity pressure-sensing aerogel material according to claim 1, characterized in that: In step (3), the concentration of MXene solution is 5-20 mg / mL, and the volume ratio of MXene stock solution to water is 1-10:

1.

6. The method for preparing the high-sensitivity pressure-sensing aerogel material according to claim 1, characterized in that: The mass ratio of MXene in step (3) to functionalized carbon nanotubes in step (2) is (5-15):

1.

7. The method for preparing the high-sensitivity pressure-sensing aerogel material according to claim 1, characterized in that: The alternating magnetic stirring and ultrasonic dispersion treatment in step (4) includes at least two magnetic stirrings and at least two ultrasonic dispersions, wherein the magnetic stirring speed is 300-500 rpm, the ultrasonic frequency is 20-40 kHz, and the treatment temperature is room temperature.

8. The method for preparing the high-sensitivity pressure-sensing aerogel material according to claim 1, characterized in that: The directional temperature gradient in step (5) is achieved by placing the mold containing the composite suspension precursor liquid on a thermal bridge and setting a cold source and a heat source at both ends of the thermal bridge respectively; the cold source is liquid nitrogen and the heat source is room temperature water or a low temperature constant temperature medium.

9. The method for preparing the high-sensitivity pressure-sensing aerogel material according to claim 1, characterized in that: In step (6), the temperature of the cold trap of the vacuum dryer is -100℃ to -60℃.

10. A highly sensitive pressure-sensing aerogel material, characterized in that, It is prepared by the preparation method described in any one of claims 1-9.

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