Composite thermal electric gel preparation method, aerogel sensor and health monitoring system

Abstract

The invention discloses a composite thermal electric gel preparation method, an aerogel sensor and a health monitoring system.The composite thermal electric gel preparation method comprises the steps that a, MXene dispersion liquid is added into SWCNT dispersion liquid, and SWCNT / MXene mixed dispersion liquid is obtained; b, adding a water-absorbing polyurethane sponge into the SWCNT / MXene mixed dispersion liquid, carrying out cyclic treatment on the water-absorbing polyurethane sponge in the SWCNT / MXene mixed dispersion liquid by adopting an external stress and vacuum assistance mode, and introducing an SWCNT / MXene conductive network structure in a gradient manner; and c, carrying out vacuum drying on the polyurethane sponge into which the SWCNT / MXene conductive network structure is introduced, then repeatedly executing the step b, and then carrying out vacuum drying to obtain the SWCNT / MXene polyurethane composite thermal electric gel.

Description

Technical Field

[0001] The present invention relates to the technical field of thermoelectric materials, and more specifically to a method for preparing a composite thermoelectric gel, an aerogel sensor and a health monitoring system. Background Art

[0002] With the rapid development of the Internet of Things, artificial intelligence and wearable medical technology, the application demand for flexible electronic devices in the fields of human health monitoring, disease warning and personalized medicine is becoming increasingly urgent. Traditional medical sensors mostly rely on external power supply, and have bottleneck problems such as bulky size, limited endurance, and poor wearing comfort. Thermoelectric materials can directly convert the temperature difference between the body surface and the environment into electrical energy, providing an ideal solution for the development of lightweight, passive flexible health monitoring devices. Therefore, the construction of self-powered sensing materials based on thermoelectric materials is of great significance in the field of wearable medical electronics.

[0003] However, existing conventional inorganic thermoelectric materials (such as Bi 2 Te 3 , PbTe, etc.) are difficult to meet the mechanical adaptability and biosafety requirements of flexible devices due to their intrinsic brittleness, high processing temperature and heavy metal toxicity. Organic thermoelectric materials have attracted attention due to their good flexibility and solution processability, but their thermoelectric performance and thermal stability (long-term operating temperature <100°C) are significantly behind those of inorganic materials, making it difficult to meet the needs of wearable devices for high-sensitivity signal acquisition and tolerance to complex environments.

[0004] In recent years, people have found that by combining different materials, the performance advantages of different components can be integrated, and properties that a single material does not have can be exhibited. Carbon-based nanomaterials (such as carbon nanotubes and graphene) have excellent mechanical flexibility, which provides a new direction for the development of flexible thermoelectric materials. In order to synergistically improve the thermoelectric properties and mechanical adaptability of materials, researchers have tried to combine SWCNT and MXene. However, existing composite strategies are mostly limited to simple physical blending or layer-by-layer stacking to construct thin film materials. Problems such as high thermal conductivity and weak mechanical durability still restrict their practical application. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method for preparing a composite thermoelectric gel with high thermoelectric performance, high temperature resistance and excellent mechanical properties, an aerogel sensor and a health monitoring system.

[0006] In order to solve the above technical problems, according to one aspect of the present invention, a method for preparing a composite thermal electrical gel is provided, comprising:

[0007] a. Adding MXene dispersion to SWCNT dispersion to obtain SWCNT / MXene mixed dispersion;

[0008] b. Adding a water-absorbent polyurethane sponge to the SWCNT / MXene mixed dispersion, and cyclically treating the water-absorbent polyurethane sponge in the SWCNT / MXene mixed dispersion by applying external stress and vacuum assistance, so as to introduce a SWCNT / MXene conductive network structure in a gradient manner;

[0009] c. The polyurethane sponge after the SWCNT / MXene conductive network structure is introduced is vacuum dried, and then the above b is repeated, and then vacuum dried again to obtain the SWCNT / MXene@polyurethane composite thermoelectric gel.

[0010] The further technical solution is as follows: in said b, the water-absorbent polyurethane sponge in the SWCNT / MXene mixed dispersion is subjected to a circulation treatment by means of external stress and vacuum assistance, specifically comprising: applying stress to the water-absorbent polyurethane sponge in the SWCNT / MXene mixed dispersion for immersion treatment, and then placing it in a vacuum drying oven for vacuum circulation treatment.

[0011] The further technical solution is as follows: in the above b, applying stress to the water-absorbent polyurethane sponge in the SWCNT / MXene mixed dispersion specifically includes: pressing, bearing or twisting the water-absorbent polyurethane sponge in the SWCNT / MXene mixed dispersion.

[0012] Its further technical solution is: before the step a, it also includes: a1, adding single-walled carbon nanotubes into an alcohol solvent, and ultrasonically dispersing them to obtain a SWCNT dispersion.

[0013] The further technical solution is as follows: in the above a1, the mass of the single-walled carbon nanotubes is 6 mg-24 mg; and the ultrasonic dispersion time is 10-50 min.

[0014] A further technical solution is as follows: in a, the concentration of the MXene dispersion is 1 mg / mL-10 mg / mL; the mass fraction of the MXene is 0.5%, 3.5%, 5.2%, 10%, 19%, 26%, 32%, 41%, 52%, 66%, 74%, 85% or 90%.

[0015] Its further technical solution is: in said b, the shape of the water-absorbent polyurethane sponge is a cylinder, a cube, a cuboid or a quadrangular prism; the length, width and height of the water-absorbent polyurethane sponge are 0.5-5cm, 1-5cm and 0.5-5cm respectively; the number of the water-absorbent polyurethane sponges is 1-9.

[0016] Its further technical solution is: in said c, the vacuum drying temperature is 40-70°C.

[0017] In order to solve the above technical problems, according to another aspect of the present invention, an aerogel sensor is provided, which includes an aerogel-based sensor array, wherein the aerogel-based sensor array includes a plurality of SWCNT / MXene@polyurethane composite thermoelectric gels prepared by the above-mentioned composite thermoelectric gel preparation method, and the plurality of SWCNT / MXene@polyurethane composite thermoelectric gels are connected and assembled using the memristor principle, or, after the plurality of SWCNT / MXene@polyurethane composite thermoelectric gels are arranged in different regions, the SWCNT / MXene@polyurethane composite thermoelectric gels in each region are connected and assembled using the memristor principle.

[0018] To solve the above technical problems, the present invention also provides a health monitoring system, which includes an aerogel sensor, a data collector, a data processor, a voltage amplifier, an analog-to-digital converter and a buzzer connected in sequence, wherein the aerogel sensor is the above-mentioned aerogel sensor.

[0019] Compared with the prior art, the present invention controls the ratio of SWCNT and MXene through the synergistic strategy of "three-dimensional conductive network in-situ self-assembly-gradient interface strengthening", and realizes the controllable preparation of multi-scale structure, high-performance, high-temperature resistant SWCNT / MXene@polyurethane composite thermoelectric gel by means of stress-vacuum assisted cyclic treatment, that is, by adding a water-absorbent polyurethane sponge into a SWCNT / MXene mixed dispersion and cyclically treating the water-absorbent polyurethane sponge in the SWCNT / MXene mixed dispersion in an external stress and vacuum-assisted manner, so that the SWCNT / MXene mixed dispersion penetrates layer by layer from the outer layer to the inner layer of the water-absorbent polyurethane sponge, so that a SWCNT / MXene conductive network is gradiently introduced into the three-dimensional microporous structure of the water-absorbent polyurethane sponge to form a conductive network, and after vacuum drying, a SWCNT / MXene@polyurethane composite thermoelectric gel with low thermal conductivity, excellent mechanical properties, high flame retardancy of MXene, high electrical conductivity and high Seebeck coefficient of SWCNT is obtained, the preparation process is simple, environmentally friendly and low cost, and can be adapted to high temperature environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic flow chart of a specific embodiment of the method for preparing the composite thermoelectric gel of the present invention.

[0021] Figure 2 This is a scanning electron microscope image of the SWCNT / MXene@polyurethane composite thermoelectric gel in Example 3. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to more clearly understand the objectives, technical solutions and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0023] Reference Figure 1 , Figure 1 The process diagram of a specific embodiment of the method for preparing the composite thermoelectric gel of the present invention is shown in the figure. In the embodiment shown in the figure, the method for preparing the composite thermoelectric gel comprises:

[0024] S101, adding single-walled carbon nanotubes into an alcohol solvent, and performing ultrasonic dispersion to obtain a SWCNT dispersion.

[0025] In this step, a cell crusher can be used for ultrasonic dispersion, and the ultrasonic dispersion time can be 10-50 min, for example, 10 min, 15 min, 20 min, 30 min, 40 min or 50 min; the mass of the single-walled carbon nanotube (SWCNT) can be 6 mg-24 mg, for example, 6 mg, 12 mg, 14 mg, 17 mg, 19 mg or 24 mg; and the alcohol solvent is preferably an ethanol solvent.

[0026] S102, adding MXene dispersion to SWCNT dispersion to obtain SWCNT / MXene mixed dispersion.

[0027] In this step, the concentration of the MXene dispersion is 1 mg / mL-10 mg / mL, for example, 1 mg / mL, 2 mg / mL, 3 mg / mL, 5 mg / mL, 7 mg / mL, 10 mg / mL; the mass fraction of the MXene is 0.5%, 3.5%, 5.2%, 10%, 19%, 26%, 32%, 41%, 52%, 66%, 74%, 85% or 90%.

[0028] Preferably, after adding the MXene dispersion, ultrasonic dispersion can be continued through a cell crusher to accelerate the mixing of the solution.

[0029] S103, adding a water-absorbent polyurethane sponge to the SWCNT / MXene mixed dispersion, and cyclically treating the water-absorbent polyurethane sponge in the SWCNT / MXene mixed dispersion by means of external stress and vacuum assistance, so as to introduce a SWCNT / MXene conductive network structure in a gradient manner.

[0030] In this step, the use of external stress and vacuum assistance to circulate the water-absorbent polyurethane sponge in the SWCNT / MXene mixed dispersion specifically includes: applying stress to the water-absorbent polyurethane sponge in the SWCNT / MXene mixed dispersion for impregnation treatment, and then placing it in a vacuum drying oven for vacuum circulation treatment, that is, through the vacuum environment to assist the circulation impregnation treatment, the water-absorbent polyurethane sponge is promoted to be impregnated with the SWCNT / MXene mixed dispersion under vacuum, so that the SWCNT / MXene mixed dispersion penetrates layer by layer from the outer layer to the inner layer of the water-absorbent polyurethane sponge. Among them, the stress can be applied repeatedly for multiple times to fully carry out the impregnation treatment, the temperature in the vacuum drying oven is room temperature, and the number of vacuum environment assisted circulation treatments can be 1, 2, 3, 4, 5 or 6 times.

[0031] Preferably, applying stress to the water-absorbent polyurethane sponge in the SWCNT / MXene mixed dispersion specifically comprises: pressing, bearing or twisting the water-absorbent polyurethane sponge in the SWCNT / MXene mixed dispersion.

[0032] In the present invention, water-absorbent polyurethane sponges cut to a certain size, shape and number can be added to the SWCNT / MXene mixed dispersion, wherein the shape of the water-absorbent polyurethane sponge can be a cylinder, a cube, a cuboid or a quadrangular prism; the length, width and height of the water-absorbent polyurethane sponge can be 0.5-5 cm, 1-5 cm and 0.5-5 cm, respectively, for example, the length, width and height can all be 1 cm; the number of the water-absorbent polyurethane sponges can be 1-9, for example, the number can be 1, 3, 5, 7 or 9.

[0033] S104, vacuum drying the polyurethane sponge after introducing the SWCNT / MXene conductive network structure, and then repeating the above step S103, and then vacuum drying to obtain the SWCNT / MXene@polyurethane composite thermoelectric gel.

[0034] In the present invention, the polyurethane sponge after introducing the SWCNT / MXene conductive network structure is placed in a vacuum drying oven for vacuum drying. The vacuum drying temperature is 40-70°C, for example, 40°C, 50°C, 60°C or 70°C, to obtain a uniform, lightweight, porous and highly elastic SWCNT / MXene@polyurethane composite thermoelectric gel.

[0035] It can be seen that the preparation method of the composite thermoelectric gel of the present invention introduces a gradient of SWCNT with a high Seebeck coefficient and MXene with a high electrical conductivity into the three-dimensional microporous structure of a water-absorbent polyurethane sponge to form a three-dimensional conductive network, and obtains a uniform, lightweight, porous and highly elastic SWCNT / MXene@polyurethane composite thermoelectric gel, which retains the high electrical conductivity and high Seebeck coefficient of SWCNT and has the high flame retardancy of MXene. The multi-layer microporous structure of the polyurethane sponge can also reduce the thermal conductivity, and has excellent mechanical properties, strong mechanical durability, and temperature-pressure sensing characteristics, which synergistically realizes the advantages of each component in the SWCNT / MXene@polyurethane composite thermoelectric gel, and has the advantages of simple preparation process, environmental friendliness, low cost, etc. The instruments and equipment used are all conventional equipment, which are simple and safe to operate and easy to industrialize.

[0036] The preparation method of the composite thermal electrical gel of the present invention is described below in conjunction with specific embodiments:

[0037] Example 1

[0038] (1) At room temperature, 12 mg of single-walled carbon nanotubes were added to ethanol and ultrasonically dispersed for 20 min using a cell crusher to obtain a SWCNT / MXene mixed dispersion;

[0039] (2) Add 3 mg / mL of MXene dispersion to the SWCNT / MXene mixed dispersion obtained in step (1) above, with a mass fraction of MXene of 32%, and continue ultrasonic dispersion for 10 min;

[0040] (3) placing five cylindrical polyurethane sponges (diameter × height = 1 cm × 1 cm) in the above SWCNT / MXene dispersion;

[0041] (4) firstly apply external stress, press repeatedly, and immerse for 3 times (10 seconds each time), then place in a vacuum drying oven, and immerse in a vacuum environment for 2 times (1 minute each time), to obtain a polyurethane sponge with a SWCNT / MXene conductive network structure;

[0042] (5) The polyurethane sponge with the SWCNT / MXene conductive network structure introduced in step (4) is placed in a glass dish and dried at 60°C. After drying, the sponge is taken out and the operation of step (4) is repeated, and then dried at 60°C. This is repeated three times to obtain a SWCNT / MXene@polyurethane composite thermoelectric gel.

[0043] The thermoelectric properties of the SWCNT / MXene@polyurethane composite thermoelectric gel obtained according to the ratio of this embodiment are as follows: The Seebeck coefficient is 48.7μVK-1 , conductivity is 1.19Scm -1 , the power factor is 0.282μWm -1 K -2 .

[0044] Example 2

[0045] The method is similar to that of Example 1, and the specific steps are as follows:

[0046] (1) At room temperature, 17 mg of single-walled carbon nanotubes were added to ethanol and ultrasonically dispersed for 20 min using a cell crusher to obtain a SWCNT / MXene mixed dispersion;

[0047] (2) Add 3 mg / mL of MXene dispersion to the SWCNT / MXene mixed dispersion obtained in step (1) above, with a mass fraction of MXene of 32%, and continue ultrasonic dispersion for 10 min;

[0048] (3) placing five cylindrical polyurethane sponges (diameter × height = 1 cm × 1 cm) in the above SWCNT / MXene dispersion;

[0049] (4) firstly apply external stress, press repeatedly, and immerse for 5 times (10 seconds each time), then place in a vacuum drying oven, and immerse in a vacuum environment for 2 times (1 minute each time), to obtain a polyurethane sponge with a SWCNT / MXene conductive network structure;

[0050] (5) The polyurethane sponge with the SWCNT / MXene conductive network structure introduced in step (4) is placed in a glass dish and dried at 60°C. After drying, the sponge is taken out and the operation of step (4) is repeated, and then dried at 60°C. This is repeated three times to obtain a SWCNT / MXene@polyurethane composite thermoelectric gel.

[0051] The thermoelectric properties of the SWCNT / MXene@polyurethane composite thermoelectric gel obtained according to the ratio of this embodiment are as follows: The Seebeck coefficient is 52.2μVK -1 , conductivity is 1.34Scm -1 , power factor is 0.365μWm -1 K -2 .

[0052] Example 3

[0053] The method is similar to that of Example 2, except that the concentration of MXene in step (2) is changed to 5 mg / mL, and the number of vacuum cycle treatments in step (4) is changed to 3 times. The cross-sectional scanning electron micrograph of the SWCNT / MXene@polyurethane composite thermoelectric gel finally prepared in this example is shown in FIG. Figure 2 As shown, it can be known that the SWCNT / MXene@polyurethane composite thermoelectric gel is a three-dimensional porous network structure, and from the corresponding magnified cross-sectional scanning electron microscope image, it can be seen that MXene and SWCNT are evenly distributed. The thermoelectric properties of the SWCNT / MXene@polyurethane composite thermoelectric gel obtained in this embodiment are as follows: The Seebeck coefficient is 68.7μVK -1 , the conductivity is 1.11Scm -1 , the power factor is 0.524μWm -1 K -2 .

[0054] Example 4

[0055] The method is similar to that of Example 2, except that the size of the cylindrical polyurethane sponge in step (3) is changed. When the size of the cylindrical polyurethane sponge (diameter × height = 1 cm × 1 cm) in Example 2 is changed to diameter × height = 1 cm × 2 cm, the Seebeck coefficient of the prepared SWCNT / MXene@polyurethane composite thermoelectric gel is 63.2 μVK -1 , conductivity is 0.88Scm -1 , the power factor is 0.351μWm -1 K -2 When the size of the cylindrical polyurethane sponge (diameter × height = 1 cm × 1 cm) in Example 2 is changed to diameter × height = 2 cm × 1 cm, the Seebeck coefficient of the prepared SWCNT / MXene@polyurethane composite thermoelectric gel is 69.1 μVK -1 , conductivity is 1.15Scm -1 , the power factor is 0.549μWm -1 K -2 When the size of the cylindrical polyurethane sponge (diameter × height = 1 cm × 1 cm) in Example 2 is changed to diameter × height = 2 cm × 2 cm, the Seebeck coefficient of the prepared SWCNT / MXene@polyurethane composite thermoelectric gel is 63.2 μVK -1 , conductivity is 0.88Scm -1 , the power factor is 0.351μWm -1 K -2When the size of the cylindrical polyurethane sponge (diameter × height = 1 cm × 1 cm) in Example 2 is changed to diameter × height = 2 cm × 2.5 cm, the Seebeck coefficient of the obtained SWCNT / MXene@polyurethane composite thermoelectric gel is 57.5 μVK -1 , conductivity is 0.67Scm -1 , the power factor is 0.221μWm - 1 K -2 .

[0056] Example 5

[0057] The method is similar to that of Example 2, except that the shape and size of the polyurethane sponge in step (3) are changed. When the polyurethane sponge added in Example 2 is changed to a cubic polyurethane sponge (length × width × height = 1 cm × 1 cm × 1 cm), the Seebeck coefficient of the prepared SWCNT / MXene@polyurethane composite thermoelectric gel is 68.5 μVK -1 , conductivity is 1.01Scm -1 , the power factor is 0.474μWm -1 K -2 When the polyurethane sponge added in Example 2 is changed to a rectangular polyurethane sponge (length × width × height = 1 cm × 1 cm × 2 cm), the Seebeck coefficient of the prepared SWCNT / MXene@polyurethane composite thermoelectric gel is 60.2 μVK -1 , conductivity is 0.73Scm -1 , the power factor is 0.264μWm -1 K -2 When the polyurethane sponge added in Example 2 is replaced with a tetrahedral polyurethane sponge (length × width × height = 1 cm × 1 cm × 2 cm), the Seebeck coefficient of the obtained SWCNT / MXene@polyurethane composite thermoelectric gel is 60.3 μVK -1 , conductivity is 0.71Scm -1 , the power factor is 0.258μWm -1 K -2 .

[0058] Example 6

[0059] The method is similar to that of Example 2, except that the number of times step (4) is repeated in step (5) is changed. When the number of times step (4) is repeated in step (5) is changed to 2 times, the Seebeck coefficient of the prepared SWCNT / MXene@polyurethane composite thermoelectric gel is 60.1 μVK -1 , conductivity is 0.98Scm -1, the power factor is 0.354μWm -1 K -2 When the number of repetitions of step (4) in step (5) is changed to 4 times, the Seebeck coefficient of the obtained SWCNT / MXene@polyurethane composite thermoelectric gel is 65.9μVK -1 , conductivity is 1.23Scm -1 , the power factor is 0.534μWm -1 K -2 When the number of repetitions of step (4) in step (5) is changed to 5 times, the Seebeck coefficient of the prepared SWCNT / MXene@polyurethane composite thermoelectric gel is 58.4μVK -1 , conductivity is 1.31Scm -1 , the power factor is 0.447μWm -1 K -2 .

[0060] In summary, the present invention controls the ratio of SWCNT and MXene through the synergistic strategy of "three-dimensional conductive network in situ self-assembly-gradient interface strengthening", and uses stress-vacuum assisted cyclic treatment to achieve the controllable preparation of SWCNT / MXene@polyurethane composite thermoelectric gel with multi-scale structure, high performance (high conductivity and high Seebeck coefficient), and high temperature resistance.

[0061] In the present invention, when the SWCNT / MXene@polyurethane composite thermoelectric gel prepared according to Example 3 of the present invention is placed under a flame and burned, the flame retardant composite thermoelectric material maintains a stable structure under the flame, and the macrostructure after burning for 100 seconds is not much different from that before burning, with only a slight volume shrinkage as a whole, and an excellent flame retardant effect.

[0062] The present invention also provides an aerogel sensor, the aerogel sensor includes an aerogel-based sensor array, the aerogel-based sensor array includes a plurality of SWCNT / MXene@polyurethane composite thermoelectric gels prepared by the composite thermoelectric gel preparation method described in the above embodiment, the plurality of SWCNT / MXene@polyurethane composite thermoelectric gels are connected and assembled using the memristor principle, or the SWCNT / MXene@polyurethane composite thermoelectric gels are arranged in different regions and the SWCNT / MXene@polyurethane composite thermoelectric gels in each region are connected and assembled using the memristor principle. Based on the above design, the whole can be connected and assembled using the memristor principle, or it can be connected and assembled using the memristor principle after being divided into regions. The aerogel-based sensor array connected and assembled using the memristor principle after being divided into regions has a more flexible structure, good stability, and the signal changes on each SWCNT / MXene@polyurethane composite thermoelectric gel can be monitored in time. Understandably, the aerogel sensor of the present invention can monitor diabetic foot by relying on its high Seebeck coefficient, detect abnormal local temperature of the sole of the foot in time, and prevent ulcer formation; it can also monitor the status of athletes, record the temperature changes of their feet, and analyze the intensity and fatigue of exercise; and it can be combined with its high rebound characteristics, according to the temperature difference and pressure changes in different regions, evaluate the gait and the force of the sole of the foot, and can be used for rehabilitation training, monitoring the gait of patients and evaluating the progress of postoperative rehabilitation and posture correction gait abnormality detection, and assisting in correcting problems such as arch collapse and inward and outward eight. And because the aerogel sensor prepared by the present invention is also resistant to high temperatures, the insole can also monitor the sole temperature and gait in extreme environments, for example, for the health monitoring of high temperature workers: such as firefighters and smelting workers, real-time monitoring of foot temperature to prevent overheating injuries; it can also be used for outdoor extreme sports: such as desert hiking, high temperature competitions, monitoring foot temperature and exercise status, and warning of high temperature heatstroke risks.

[0063] It can be understood that the present invention also provides a health monitoring system, which includes an aerogel sensor, a data collector, a data processor, a voltage amplifier, an analog-to-digital converter and a buzzer connected in sequence, wherein the aerogel sensor is the aerogel sensor described in the above embodiment, the data collector can collect temperature, voltage, resistance, and capacitance signals, the data processor can display and process the generated electrical signals in real time, the voltage amplifier can realize signal amplification, the analog-to-digital converter is used to realize the conversion between electrical signals and digital signals, and the buzzer is used to issue an early warning when the set threshold is reached.

[0064] The following describes the operation of the health monitoring system of the present invention in conjunction with specific application scenarios:

[0065] Application Scenario 1

[0066] The SWCNT / MXene@polyurethane composite thermoelectric gel prepared in the above-mentioned embodiment 3 is encapsulated with conductive silver glue, copper foil and polyamide sub-film, and is connected and assembled using the regional memristor principle in combination with the monitoring part of the human body to form a wearable device. For example, if the sole of the foot is monitored, the assembled aerogel sensor of the corresponding shape is used as a wearable insole, and each aerogel-based sensor array in the aerogel sensor is connected to a data collector, so that the detected sensor information is collected by the data collector and processed by the data processor. When the preset warning threshold is exceeded, the voltage amplifier and the analog-to-digital converter are used to generate a warning signal. After that, the buzzer is driven for early warning. For example, the wearable insole is placed on a constant temperature bottom plate at a temperature of 32°C, and a cup of warm water at 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, 39°C, and 40°C is placed on the upper end of the wearable insole to simulate the slight temperature difference of the human foot. Under different temperature stimuli, the voltage changes can be quickly collected, and the generated voltages are 67.3μV, 133.8μV, 200.9μV, 270μV, 339μV, 405.5μV, 466.4μV, and 546μV, respectively, and the response time is extremely fast at 0.1s. The collected voltage changes can timely detect the abnormal temperature of the sole of the foot. When the preset warning threshold is 500μV, the generated voltage exceeds 500μV, and the buzzer is used for early warning. In addition, the exercise intensity and fatigue state can be analyzed according to the temperature changes of the foot.

[0067] Application Scenario 2

[0068] The SWCNT / MXene@polyurethane composite thermoelectric gel prepared in the above embodiment 3 is encapsulated with conductive silver glue, copper foil and polyamide sub-film, and is connected and assembled using the principle of regional memristor in combination with the human body monitoring part to form a wearable device. For example, the human body monitoring part is a special point in the foot where the human body sole contacts, such as the arch, heel, toe, etc. The heel, arch and toe of the sole are used in turn to accurately locate and stimulate each aerogel-based sensor array in the insole, and then the change in the resistance value of the corresponding sensor array is collected. When the insole sensor is stimulated by the heel, the change in resistance is recorded, and the resistance value detected when not stimulated is 1.95Ω, and the resistance value after stimulation is 0.32Ω. When collecting the change in resistance data, the response of the sensor is very rapid, and the response time can also reach 0.1s. When the sensor in the insole is stimulated by the arch, the change in resistance is also recorded, and the resistance value detected when not stimulated is 3.5Ω, and the resistance value after stimulation is 0.2Ω. The response time is also very rapid, reaching a response time of 0.1s. When the insole sensor is stimulated with the toes, the change in resistance is recorded. The resistance value is 2Ω before stimulation and 0.54Ω after stimulation. Similarly, the response time is very fast when collecting the change in resistance. By analyzing the collected resistance data, the alarm threshold can be set, which allows the medical staff to monitor the force of different parts of the patient's foot in real time, adjust the walking posture, optimize the landing method, and detect abnormal pressure distribution (such as flat feet or inversion feet) during rehabilitation training or disease prevention, so as to provide personalized health advice.

[0069] From the above, it can be seen that the aerogel sensor of the present invention has a high Seebeck coefficient (high sensitivity), high resilience and high temperature resistance. The constructed health monitoring system can be applied to human posture correction, body temperature monitoring, human rehabilitation training, athlete posture monitoring, and workers in high temperature scenes. It has practical application advantages in health monitoring and sports training.

[0070] The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Those skilled in the art can make various equivalent changes and improvements based on the above embodiments, and all equivalent changes or modifications made within the scope of the claims should fall within the protection scope of the present invention.

Claims

1. A method for preparing a composite thermoelectric gel, characterized in that: The composite thermal electrical gel preparation method comprises: a. Adding MXene dispersion to SWCNT dispersion to obtain SWCNT / MXene mixed dispersion; b. Adding a water-absorbent polyurethane sponge to the SWCNT / MXene mixed dispersion, and cyclically treating the water-absorbent polyurethane sponge in the SWCNT / MXene mixed dispersion by applying external stress and vacuum assistance, so as to introduce a SWCNT / MXene conductive network structure in a gradient manner; c. The polyurethane sponge after the SWCNT / MXene conductive network structure is introduced is vacuum dried, and then the above b is repeated, and then vacuum dried again to obtain the SWCNT / MXene@polyurethane composite thermoelectric gel.

2. The method for preparing the composite thermoelectric gel according to claim 1, characterized in that: In the above b, the water-absorbent polyurethane sponge in the SWCNT / MXene mixed dispersion is subjected to a circulation treatment by means of external stress and vacuum assistance, specifically comprising: applying stress to the water-absorbent polyurethane sponge in the SWCNT / MXene mixed dispersion for immersion treatment, and then placing it in a vacuum drying oven for vacuum circulation treatment.

3. The method for preparing the composite thermoelectric gel according to claim 2, characterized in that: In the above-mentioned step b), applying stress to the water-absorbent polyurethane sponge in the SWCNT / MXene mixed dispersion specifically includes: pressing, bearing or twisting the water-absorbent polyurethane sponge in the SWCNT / MXene mixed dispersion.

4. The method for preparing the composite thermoelectric gel according to claim 1, characterized in that: Before the step a, the method further includes: a1, adding single-walled carbon nanotubes into an alcohol solvent and performing ultrasonic dispersion to obtain a SWCNT dispersion.

5. The method for preparing the composite thermoelectric gel according to claim 4, characterized in that: In the above a1, the mass of the single-walled carbon nanotubes is 6 mg-24 mg; and the ultrasonic dispersion time is 10-50 min.

6. The method for preparing the composite thermoelectric gel according to claim 1, characterized in that: In a, the concentration of the MXene dispersion is 1 mg / mL-10 mg / mL; the mass fraction of the MXene is 0.5%, 3.5%, 5.2%, 10%, 19%, 26%, 32%, 41%, 52%, 66%, 74%, 85% or 90%.

7. The method for preparing the composite thermoelectric gel according to claim 1, characterized in that: In b, the shape of the water-absorbent polyurethane sponge is a cylinder, a cube, a cuboid or a quadrangular prism; the length, width and height of the water-absorbent polyurethane sponge are 0.5-5 cm, 1-5 cm and 0.5-5 cm respectively; the number of the water-absorbent polyurethane sponges is 1-9.

8. The method for preparing the composite thermoelectric gel according to claim 1, characterized in that: In the step c, the vacuum drying temperature is 40-70°C.

9. An aerogel sensor, characterized in that: The aerogel sensor includes an aerogel-based sensor array, which includes a plurality of SWCNT / MXene@polyurethane composite thermoelectric gels prepared by the composite thermoelectric gel preparation method according to any one of claims 1 to 8, wherein the plurality of SWCNT / MXene@polyurethane composite thermoelectric gels are connected and assembled using the memristor principle, or the plurality of SWCNT / MXene@polyurethane composite thermoelectric gels are arranged in different regions, and the SWCNT / MXene@polyurethane composite thermoelectric gels in each region are connected and assembled using the memristor principle.

10. A health monitoring system, characterized in that: It comprises an aerogel sensor, a data collector, a data processor, a voltage amplifier, an analog-to-digital converter and a buzzer which are connected in sequence, wherein the aerogel sensor is the aerogel sensor according to claim 9.

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