Flexible temperature sensor with high sensitivity and quick response and preparation method thereof

Abstract

The invention discloses a flexible temperature sensor with high sensitivity and quick response and a preparation method thereof. A temperature sensitive layer formed by compounding four materials is arranged in the middle, and PDMS embedded with liquid metal is used as a heat conduction layer and is distributed on the upper side and the lower side of the temperature sensitive layer. According to the temperature sensitive layer, a conductive network is formed by reduced graphene oxide and manganese dioxide, the sensitivity is improved, aramid 1313 and a thermoplastic polyester elastomer are used as substrates to provide thermal stability, the flexibility and the film-forming property of the film are ensured, and better sensitivity can be obtained. For the packaged heat conduction layer, the liquid metal tiny liquid drops after ultrasonication are fused with PDMS with stable and good performance, the liquid metal tiny liquid drops are embedded into the PDMS, the PDMS completely wraps liquid metal particles, and the situation that the resistance is greatly changed due to the fact that the heat conduction layer and the temperature-sensitive layer are connected in series is prevented. According to the invention, under the condition that the temperature is slightly changed, the numerical value of the specific change can be accurately and rapidly reflected without external interference.

Description

Technical Field

[0001] The present invention relates to the field of flexible temperature sensors, and in particular to a flexible temperature sensor with high sensitivity and rapid response and a preparation method thereof. Background Art

[0002] Driven by demand in numerous fields, including healthcare, biomimetic robotics, and prosthetics, flexible sensors have rapidly developed in recent years and demonstrated significant potential for application. Temperature is a common vital sign of the human body and many other organisms, providing insights into their movement and health. Furthermore, measuring temperature is essential for compensating for the temperature data missing from other sensor types, such as biochemical sensors. Thermistor-type flexible temperature sensors typically utilize a polymer substrate to support their flexibility and enhance mechanical properties, with conductive materials as fillers to create a conductive network. These sensors are among the most widely reported and widely used flexible temperature sensors, offering advantages such as high sensitivity, good resolution, ease of integrated manufacturing, and inexpensive, widely available materials. However, flexible temperature sensors generally suffer from poor repeatability and susceptibility to external influences, complicating data processing, reducing sensing accuracy, and even leading to device failure. Operating in complex environments can even damage the sensor. Two approaches are currently underway to address this low repeatability: mixing polymers with different melting points, with the low-temperature polymer facilitating temperature sensing and the high-temperature polymer maintaining structural stability; and using high-aspect-ratio conductive fillers, such as carbon nanotubes, to create a more stable conductive network. These methods can only improve the resistivity repeatability to a limited extent and do not fundamentally solve the problem of being easily affected by external factors.

[0003] To eliminate the influence of external factors on the temperature sensor, polydimethylsiloxane (PDMS), with its stable chemical properties and excellent physical properties, is used to encapsulate the sensor, effectively isolating it from the internal and external environments. However, the encapsulated flexible sensor becomes thicker, resulting in a delayed response time. To obtain accurate data more quickly, the temperature sensor also needs to have good fast response and recovery times. This requires the encapsulation material to have high thermal conductivity to improve heat transfer efficiency, low modulus to fill the tiny gap between the temperature sensor and the skin, and insulation properties to ensure the normal operation of the sensor without interference. Based on these considerations, the design of a new flexible temperature sensor is of great significance. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a flexible temperature sensor with high sensitivity and fast response and a preparation method thereof.

[0005] In a first aspect, the present invention provides a method for preparing a flexible temperature sensor with high sensitivity and fast response, which is achieved through the following technical solutions.

[0006] A method for preparing a flexible temperature sensor with high sensitivity and fast response, comprising the following steps:

[0007] S1. Preparation of Temperature Sensitive Layer

[0008] a. Dimethylacetamide and LiCl are mixed and stirred uniformly, wherein the mass ratio of dimethylacetamide to LiCl is 1:0.01-1:0.05; then the aramid fiber is added and stirred uniformly at high temperature; then the thermoplastic polyester elastomer is added and stirred at high temperature until completely dissolved, wherein the mass ratio of aramid fiber to thermoplastic polyester elastomer is 0.3:0.1-0.3:0.15; the mass ratio of dimethylacetamide to aramid fiber is 1:0.1-1:0.15;

[0009] b. The reduced graphene oxide and MnO2 were uniformly dispersed in a dimethylacetamide solution by ultrasonic treatment, wherein the mass ratio of reduced graphene oxide to MnO2 was 0.24:0.06-0.24:0.08;

[0010] c. The solutions obtained in step a and step b are mixed and stirred at high temperature; in the mixed solution, the mass ratio of aramid fiber and reduced graphene oxide is 0.3:0.18-0.3:0.24;

[0011] d. The solution obtained in step c was annealed at -0.085MPa for 2-4h and mechanically scraped into a 0.08-0.13mm film, and the temperature-sensitive layer was obtained after annealing.

[0012] S2. Preparation of thermally conductive packaging layer

[0013] a. Preparation of tiny liquid metal particles

[0014] Ⅰ. Mixing a gallium-indium alloy with anhydrous methanol and subjecting it to ultrasonic treatment to obtain a gallium-based liquid metal slurry; wherein the mass ratio of the gallium-indium alloy to the anhydrous methanol is 1:4-1:5;

[0015] Ⅱ. The gallium-based liquid metal slurry is centrifuged at 500-600 rpm for 60-90 seconds, the supernatant is retained, and the supernatant is further centrifuged at 900-1000 rpm for 90-100 seconds, and then the supernatant is removed and dried to obtain tiny liquid metal particles;

[0016] b. Preparation of PDMS / EGaIn layer

[0017] The tiny liquid metal particles obtained in step S2a are added to a polydimethylsiloxane solution and stirred evenly. A curing agent is then added, and the solution is placed in a vacuum environment of -0.085 MPa for a period of time. A 0.06-0.1 mm thin film is prepared by a mechanical doctor blade method, and annealing is performed to obtain a thermally conductive encapsulation layer; wherein the mass ratio of the tiny liquid metal particles to the polydimethylsiloxane is 1:1-1.1:1;

[0018] S3. Assembly

[0019] The temperature sensitive layer obtained in step S1 is placed in the middle, and the heat conductive packaging layers obtained in step S2 are distributed on the upper and lower sides of the temperature sensitive layer to form a three-layer structure.

[0020] Furthermore, in step S1a, dimethylacetamide and LiCl are stirred at 60-65° C. for 30-60 minutes; after the aramid fiber is added, stirring is continued at 90-95° C. for 2-3 hours; after the thermoplastic polyester elastomer is added, stirring is continued at 90-95° C.

[0021] Furthermore, in step S1c, the solutions obtained in step a and step b are mixed and stirred at 80-85° C. for 2-3 hours.

[0022] Furthermore, in step S1d, the annealing treatment conditions are: annealing at 60-80°C under -0.085 MPa for 1-2 hours.

[0023] Furthermore, in step S2aⅠ, the ultrasonic treatment conditions are: ultrasonic treatment at a power of 500-600 W for 10-15 minutes, and the ultrasonic treatment process is carried out in an ice water bath.

[0024] Furthermore, in step S2aⅡ, the drying conditions are: vacuum drying at room temperature for 6-8 hours.

[0025] Furthermore, in step S2b, the tiny liquid metal particles are mixed with polydimethylsiloxane and stirred at room temperature for 6-8 hours.

[0026] Furthermore, in step S2b, a curing agent is added and then treated in a vacuum environment for 4-6 hours.

[0027] Furthermore, in step S2b, the annealing treatment conditions are: annealing at 60-80°C under -0.085 MPa vacuum conditions for 1-2 hours.

[0028] In a second aspect, the present invention provides a flexible temperature sensor with high sensitivity and fast response, which is achieved through the following technical solutions.

[0029] A flexible temperature sensor with high sensitivity and fast response prepared by the above preparation method.

[0030] This application has the following beneficial effects.

[0031] The sensor of the present invention has high sensitivity and can quickly respond to temperature changes. It can accurately and quickly reflect the specific value of the temperature change even when the temperature is slightly different, without external interference. The present invention can be used not only on humans but also on animals and in various scenarios requiring temperature monitoring, indicating the impact of small temperature changes and preventing the harm caused by them. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the structure of the flexible temperature sensor of the present invention;

[0033] Figure 2 This is a scanning electron microscope image of the flexible temperature sensor of the present invention, wherein (A) is an electron microscope image of the temperature sensitive layer; (B) is an electron microscope image of the heat conductive layer;

[0034] Figure 3 The following are performance test results of the flexible temperature sensor of the present invention, including: (A) a schematic diagram of the heat transferred by liquid metal particles of different sizes; (B) a schematic diagram of heat transfer with and without a thermally conductive layer; (C) a sensitivity curve of the flexible temperature sensor; (D) a graph showing the response time required for heating liquid metal with different contents to different temperatures; (E) a graph showing the response time required for heating to different temperatures when the liquid metal content is 50 wt%; (F) a graph showing the results of cycling the sensor at 35-40°C; (G) a graph showing the change in sensor resistivity when the temperature changes by 0.5°C; and (H) a performance comparison with other temperature sensors.

[0035] Figure 4 The following are test results of the flexible temperature sensor of the present invention in terms of its resistance to external forces: (A) a schematic diagram of the principle of the sensor's resistance to external forces; (B) a diagram showing the sensitivity of the sensor at different lengths; (C) a diagram showing the sensitivity of the sensor at different pressures; (D) a diagram showing the sensitivity of the sensor at different bending angles; (E) a diagram showing the repeatability of the sensor with and without encapsulation; (F) a diagram showing the sensitivity of the sensor in different humidity environments; and (G) a diagram showing the temperature change of the sensor with and without liquid metal encapsulated in a small light bulb when operating underwater.

[0036] Figure 5Graphs showing the thermal conductivity test results of the flexible temperature sensor of the present invention, including: (A) infrared thermal imaging of the skin-sensor interface without a liquid metal PDMS thermal conductive layer; (B) infrared thermal imaging of the skin-sensor interface with a liquid metal PDMS thermal conductive layer; (C) thermal contact performance of the skin temperature sensor with and without liquid metal during exercise; (D) thermal contact performance of the skin temperature sensor with a liquid metal thermal conductive layer during exercise; (E) thermal contact performance of the skin temperature sensor without a liquid metal thermal conductive layer during exercise; (F) temperature curves measured by the dual sensors at different LED power levels; and (G) maximum temperatures measured by the dual sensors at different LED power levels.

[0037] Figure 6 The flexible temperature sensor of the present invention monitors the temperature of mouse wounds, including: (A) a diagram of the monitoring system; (B) a diagram of the cell survival rate of mouse wounds after placement of the temperature sensor; (C) a diagram of wound size over seven days with and without the temperature sensor; (D) a section comparison of proliferating cells in mouse wounds; (E) a diagram of wound size over seven days between the control and model groups; and (F) a curve showing changes in mouse wounds over seven days.

[0038] Figure 7 Figures 1 and 2 show the results of machine learning demonstrating that the flexible temperature sensor of the present invention can be used in actual products. These figures include (A) a flowchart showing the array can be used in actual products through machine learning; (B) a graph showing the resistivity change of each unit when recognizing different gestures; and (C) a graph showing the resistivity change curves of each unit in the array when sensing different temperatures. DETAILED DESCRIPTION

[0039] The present invention adjusts the thermal expansion coefficient (TEC) to be close to zero, thereby preventing the shape from shrinking or expanding with temperature changes, improving the low reproducibility of the resistivity of the thermal resistance flexible temperature sensor, and maintaining a stable state. The present invention places a temperature-sensitive layer composed of four materials in the middle position, and PDMS embedded with liquid metal is distributed as a heat-conducting layer on the upper and lower layers of the temperature-sensitive layer, with a total of three-layer structure. The shape and size of both can be adjusted according to the use environment and conditions. Specifically, the temperature-sensitive layer is composed of a conductive network of reduced graphene oxide (rGO) and manganese dioxide (MnO2) to improve sensitivity, and uses aramid 1313 (Nomex) and thermoplastic polyester elastomer (TPU) as a substrate to provide thermal stability, ensure film flexibility and film-forming properties, and through this design, a better sensitivity TCR≈-1.1%℃ can also be obtained. -1For the encapsulated thermal conductive layer, this application fuses the ultrasonically crushed liquid metal droplets with the stable PDMS, embedding them into the liquid metal droplets. The PDMS completely wraps the liquid metal particles, preventing the thermal conductive layer and the temperature sensitive layer from being connected in series and causing a large change in resistance. When the thickness is 0.1mm, it can ensure excellent flexibility and good thermal conductivity, and obtain a good response time (0.6s), laying a good foundation for flexible temperature sensors to monitor temperature.

[0040] The invention is further described below with reference to the accompanying drawings and examples. Unless otherwise specified, the experimental methods used in the present invention are conventional methods, and the experimental equipment, materials, reagents, etc. used can be purchased from relevant material sales companies.

[0041] A method for preparing a flexible temperature sensor with high sensitivity and fast response, comprising the following steps:

[0042] 1) Preparation method of temperature sensitive layer:

[0043] A) Add 2 g of DMAC (dimethylacetamide) and 0.1 g of LiCl into a beaker and heat with stirring at 60°C for 30 minutes;

[0044] B) adding 0.3 g of Nomex (Hubei Tengdi New Materials Co., Ltd., 6 mm aramid 1313) and heating and stirring at 95° C. for 2 hours;

[0045] C) Add 0.1 g of TPU (Wanhua Chemical Group Co., Ltd., molecular weight 100,000) to the solution and continue heating and stirring at 95°C until completely dissolved;

[0046] D) 0.24 g rGO (Suzhou Carbon Graphene Technology Co., Ltd., multilayer rGO) and 0.06 g MnO2 were completely and uniformly dispersed in 2 g DMAC solution by ultrasonic treatment;

[0047] E) mixing the two solutions together, heating and stirring at 80° C. for 2 hours until the mixture is uniform;

[0048] F) Place in a vacuum for 2 hours to remove the dissolved air;

[0049] G) The film was scraped into a 0.1 mm film by mechanical blade coating, and then placed in a vacuum oven for annealing at 80°C for 1 hour.

[0050] 2) Preparation method of thermal conductive packaging layer:

[0051] Preparation of tiny liquid metal particles: LM (gallium-based liquid metal) particles were prepared by dissolving 2.5 g of Egalin eutectic alloy (gallium-indium alloy) (Yuxin Alloy Co., Ltd., 16°C) in 10 g of anhydrous methanol in a 10 ml centrifuge tube. Ultrasonic treatment was performed at a power of 500 W for 10 minutes in an ultrasonic cell disruption system (Biosafer 650-92, Nanjing Biosafer Co.), during which the centrifuge tube was placed in an ice-water bath. The resulting LM slurry was centrifuged at 500 rpm for 60 seconds. The supernatant was retained and centrifuged at 1000 rpm for another 90 seconds, and then the supernatant was carefully removed. The mixture was vacuum dried at room temperature for 6 hours.

[0052] Preparation of the PDMS / EGaIn layer: 2.5g of the obtained liquid metal particles were added to 2.5g of PDMS solution and stirred at room temperature for 6 hours to ensure uniform dispersion of the particles. 0.25g of a curing agent (hydrogenated silicone oil crosslinker) was then added and stirred thoroughly. The mixture was placed under vacuum for 6 hours and then mechanically coated into a 0.1mm film. The film was then annealed in a vacuum oven at 80°C for 6 hours.

[0053] 3) Assembly

[0054] The temperature sensitive layer is placed in the middle position, and the heat conductive packaging layers are distributed on the upper and lower sides of the temperature sensitive layer to form a three-layer structure.

[0055] The flexible temperature sensor of the present invention uses PDMS as the base of the encapsulation layer, which makes the temperature sensor have excellent conformability and hydrophobicity, can be in contact with the skin in a comfortable manner for a long time, and can prevent various impurities from entering the sensor and corroding the sensor. It can also effectively resist the influence of deformation such as deformation and pressure.

[0056] Next, the performance of the flexible temperature sensor prepared in this application is tested.

[0057] (1) Figure 1 This is a schematic diagram of the temperature sensor structure. The sensor has a three-layer structure, and each element is clearly marked.

[0058] (2) Figure 2 (A) and (B) show high-magnification microscopic views of the temperature-sensitive layer and the thermally conductive encapsulation layer, along with elemental distribution maps. Sample preparation begins with spraying a conductive layer onto the sample surface. After placing the sample on a stage, the sample is characterized using a high-resolution electron microscope and then analyzed using energy dispersive spectroscopy for elemental distribution. The results clearly show the uniform and distinct distribution of elements such as C, Mn, Ga, and In.

[0059] (3) Figure 3(A) and 3(B) are schematic diagrams of the heat conduction principle of the liquid metal encapsulation layer. Figure 3 (C) is the sensitivity of the sensor, which can be expressed as TCR≈-1.1%℃-1,R 2 = 0.99488. This is obtained by fixing it on a heating stage and measuring the change in resistance while changing the temperature of the heating stage. The sensitivity is quite good. Figure 3 (D) The prepared temperature sensors with different liquid metal contents are placed on a heating table with adjustable temperature, and heated from 20°C to 30°C, 40°C, and 50°C. The resistance change is measured using a high-precision LCR at a frequency of 1kHz, thereby recording the response time. It can be seen that the response time is shorter when the liquid metal content is 50wt% and 60wt%. Figure 3 (E) is the sensor of liquid metal content with the shortest response time. It is heated from 20℃ to different temperatures and its response time is recorded. As the temperature difference becomes larger, its response time also increases accordingly. Figure 3 (F) The sensor with the best performance was cycled multiple times at 35°C and 40°C to observe its resistance change. It can be seen that its performance remains stable even after multiple cycles. Figure 3 (G) is to change the temperature in a small range, each time increasing by 0.5℃, and then measure its resistance change at the same time. It can be observed that the resistance of the sensor has a step-by-step change each time the temperature changes, indicating that it can well detect the temperature change of 0.5℃. Figure 3 (H) The sensor in this work is compared with other sensors and it is found that its sensing performance is good.

[0060] (4) Figure 4 (A) is a schematic diagram of the principle of the temperature sensor resisting external force. Figure 4 (B) Changing its length and measuring its sensitivity, its sensitivity does not change much; Figure 4 (C) Applying different pressures to the prepared temperature sensor and measuring its sensitivity, the sensitivity also changes slightly under different pressures; Figure 4 (D) The sensor is bent and its sensitivity is measured at different bending angles. It can be seen that the bending angles have little effect on the sensitivity of the temperature sensor. Figure 4 (E) Two sets of sensors (one with an encapsulation layer and one without) were subjected to multiple cycles of heating, and the sensitivity changes after different heating cycles were measured. The figure shows that the sensor with the encapsulation layer maintained relatively good sensitivity after multiple heating cycles. Figure 4 (F) The sensor is placed in different humidity environments to measure whether its sensitivity changes. Changes in ambient humidity cannot affect the internal sensitivity through the packaging layer. Figure 4(G) Small light bulbs were encapsulated in a sensor containing a liquid metal encapsulation layer and a sensor without a liquid metal encapsulation layer. The two groups of small light bulbs were placed underwater at the same time, powered on and off, and their thermal conductivity was compared. The results showed that the sensor with liquid metal had better thermal conductivity.

[0061] (5) Figure 5 Figures 5(A) and 5(B) are schematic diagrams comparing heat transfer with and without temperature sensors embedded with liquid metal. The encapsulation layer with liquid metal transfers heat faster. The two sets of sensors are attached to the skin. The temperature of a person changes during activity. Infrared imaging is used to record the temperature after each exercise session, after 10 minutes, 20 minutes, 30 minutes of exercise, and after 30 minutes of rest. Figure 5 (C) shows the temperatures recorded by the two sets of sensors and the skin temperature. As the skin temperature increases, the temperatures sensed by the two sets of sensors also increase, but the results show that the temperature of the sensor with liquid metal encapsulation layer is closer to the skin temperature. Figure 5 (D) and 5(E) encapsulate the LED bulb into two sets of sensors, making them work at different powers, and their temperatures will also produce different changes. Similarly, infrared imaging is used to record the images of the two sets after heating for different times. Figure 5 (F) is the temperature change recorded by the sensor when the small bulb is heated at different powers. Figure 5 (G) is the highest temperature recorded by the two sets of sensors when the small bulb is heated at different powers. It can be seen from the chart that the temperature of the sensor with liquid metal encapsulation layer is closer to the temperature of the small bulb itself.

[0062] (6) Figure 6 (A) is the structure diagram of the temperature monitoring system. Figure 6 (B) shows the cell survival rates of three groups of mice (one group is a blank control group, one group is pure PDMS, and the last group is attached with sensors). It can be seen that the cell survival rates of the three groups of mice are similar, and the sensor does not affect the survival of mouse cells; Figure 6 (C) A temperature sensor was attached to the surface of the mouse wound as part of a temperature monitoring system, and the wound conditions of two groups of mice (blank group and sensor-attached group) were recorded using a camera. Figure 6 (D) The cell sections of the mice were stained, and the survival status of the cells in the two control groups was observed under an optical microscope. It can be seen that during the wound healing process of the mice, the temperature sensor did not affect the cell survival in the wound. Figure 6(E) shows the seven-day changes in wound area in the control group and the model group. The wounds of the mice gradually cooled down to normal body temperature during the healing process. The change in wound temperature caused the resistance of the temperature sensor to change. The detection system collected the resistance change signal and transmitted it to the mobile terminal, which was finally processed into a temperature signal for display. After comparison, the mice with temperature sensors even recovered faster, indicating that the sensor helps the mice recover from their wounds. Figure 6 (F) The sensor records temperature changes during wound healing in mice. The results show that the temperature sensor monitors temperature changes without affecting the survival rate of mouse cells and can even accelerate wound healing.

[0063] (7) Figure 7 (A) combines individual temperature sensor modules into an array, and can use machine learning to combine the signals of a finger passing through the array into a database for classification, recognition, storage, and output as different letters (such as Figure 7 (B)), and then use these letters in actual scenarios. Figure 7 (C) By placing water of different temperatures in a culture dish and letting it identify the temperature, we can see its sensitivity to temperature. After a series of machine learning, it can be applied to actual scenarios to achieve results in temperature monitoring.

[0064] The embodiments of this specific implementation method are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a flexible temperature sensor with high sensitivity and fast response, characterized by: The following steps are involved: S1. Preparation of Temperature Sensitive Layer a. Dimethylacetamide and LiCl are mixed and stirred uniformly, wherein the mass ratio of dimethylacetamide to LiCl is 0.01:1-0.05:1; then the aramid fiber is added and stirred uniformly at high temperature; then the thermoplastic polyester elastomer is added and stirred at high temperature until completely dissolved, wherein the mass ratio of the aramid fiber to the thermoplastic polyester elastomer is 0.3:0.1-0.3:0.15; the mass ratio of dimethylacetamide to the aramid fiber is 1:0.1-1:0.15; b. The reduced graphene oxide and MnO2 were uniformly dispersed in a dimethylacetamide solution by ultrasonic treatment, wherein the mass ratio of reduced graphene oxide to MnO2 was 0.24:0.06-0.24:0.08; c. The solutions obtained in step a and step b are mixed and stirred at high temperature; in the mixed solution, the mass ratio of aramid fiber and reduced graphene oxide is 0.3:0.18-0.3:0.24; d. The solution obtained in step c was annealed at -0.085MPa for 2-4h and mechanically scraped into a 0.08-0.13mm film, and the temperature-sensitive layer was obtained after annealing. S2. Preparation of thermally conductive packaging layer a. Preparation of tiny liquid metal particles Ⅰ. Mixing a gallium-indium alloy with anhydrous methanol and subjecting it to ultrasonic treatment to obtain a gallium-based liquid metal slurry; wherein the mass ratio of the gallium-indium alloy to the anhydrous methanol is 1:4-1:5; Ⅱ. The gallium-based liquid metal slurry is centrifuged at 500-600 rpm for 60-90 seconds, the supernatant is retained, and the supernatant is further centrifuged at 900-1000 rpm for 90-100 seconds, and then the supernatant is removed and dried to obtain tiny liquid metal particles; b. Preparation of PDMS / EGaIn layer The tiny liquid metal particles obtained in step S2a are added to a polydimethylsiloxane solution and stirred evenly. A curing agent is then added, and the solution is placed in a vacuum environment of -0.085 MPa for a period of time. A 0.06-0.1 mm thin film is prepared by a mechanical doctor blade method, and annealing is performed to obtain a thermally conductive encapsulation layer; wherein the mass ratio of the tiny liquid metal particles to the polydimethylsiloxane is 1:1-1.1:1; S3. Assembly The temperature sensitive layer obtained in step S1 is placed in the middle, and the heat conductive packaging layers obtained in step S2 are distributed on the upper and lower sides of the temperature sensitive layer to form a three-layer structure.

2. The method for preparing a flexible temperature sensor with high sensitivity and fast response according to claim 1, characterized in that: In step S1a, dimethylacetamide and LiCl are stirred at 60-65° C. for 30-60 minutes; after adding the aramid fiber, stirring is continued at 90-95° C. for 2-3 hours; after adding the thermoplastic polyester elastomer, stirring is continued at 90-95° C.

3. The method for preparing a flexible temperature sensor with high sensitivity and fast response according to claim 1, characterized in that: In step S1c, the solutions obtained in step a and step b are mixed and stirred at 80-85° C. for 2-3 hours.

4. The method for preparing a flexible temperature sensor with high sensitivity and fast response according to claim 1, characterized in that: In step S1d, the annealing treatment conditions are: annealing at 60-80°C under -0.085 MPa for 1-2 hours.

5. The method for preparing a flexible temperature sensor with high sensitivity and fast response according to claim 1, characterized in that: In step S2aⅠ, the ultrasonic treatment conditions are: ultrasonic treatment at a power of 500-600 W for 10-15 minutes, and the ultrasonic treatment process is carried out in an ice water bath.

6. The method for preparing a flexible temperature sensor with high sensitivity and fast response according to claim 1, characterized in that: In step S2aⅡ, the drying conditions are: vacuum drying at room temperature for 6-8 hours.

7. The method for preparing a flexible temperature sensor with high sensitivity and fast response according to claim 1, characterized in that: In step S2b, the tiny liquid metal particles are mixed with polydimethylsiloxane and stirred at room temperature for 6-8 hours.

8. The method for preparing a flexible temperature sensor with high sensitivity and fast response according to claim 1, characterized in that: In step S2b, after adding the curing agent, the mixture is treated under vacuum for 4-6 hours.

9. The method for preparing a flexible temperature sensor with high sensitivity and fast response according to claim 1, characterized in that: In step S2b, the annealing treatment conditions are: annealing at 60-80°C for 1-2 hours under a vacuum condition of -0.085 MPa.

10. A flexible temperature sensor with high sensitivity and fast response prepared by the preparation method according to any one of claims 1 to 9.

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