Preparation method and application of thermosensitive composite temperature sensor

Abstract

The invention relates to the technical field of temperature sensors, in particular to a preparation method and application of a thermosensitive composite temperature sensor, and the preparation method comprises the following steps: 1, synthesizing MXene; step 2, preparing a thermosensitive composite material; step 3, preparing the thermosensitive temperature sensing yarn or fabric; 4, packaging the modified cashmere yarn or cashmere fabric; the application range of the temperature sensor is widened; not only is the production cost remarkably reduced, but also the uniformity and stability of the composite material on the substrate are ensured, and feasibility is provided for large-scale industrial production; the environment adaptability and the long-term service life of the sensor are greatly improved, the design breaks through the limitation that a traditional flexible temperature sensor is prone to being interfered by the environment and is fast in performance attenuation, and technical guarantee is provided for high-reliability intelligent textiles.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature sensors, and in particular to a preparation method and application of a thermally sensitive composite temperature sensor. Background Art

[0002] As a key device for sensing and measuring temperature changes, temperature sensors have broad application prospects in the fields of smart wearable devices, environmental monitoring, and medical health. However, many temperature sensors, such as the temperature sensor structure disclosed in the invention patent with announcement number CN102165296B and the temperature sensor and method for manufacturing the temperature sensor disclosed in the invention patent with announcement number CN106323495B, can detect temperature.

[0003] However, during use, it was found that existing temperature sensors still have many limitations in terms of performance, flexibility and application scope. Their thermal response performance and mechanical stability are usually poor, which makes it difficult to meet the actual needs of smart textiles. Therefore, there is an urgent need for the preparation method and application of thermosensitive composite temperature sensors to improve the above problems. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method of applying a thermosensitive composite material to a flexible substrate of cashmere fiber, which takes into account functionality and flexibility. The unique softness, ductility and adaptability of cashmere fiber enable the sensor to fit complex curved surfaces or dynamic motion scenes, meet the flexibility and comfort requirements of smart wearable devices, and thus broaden the application scope of the temperature sensor; the thermosensitive composite material is coated on the flexible cashmere substrate by an impregnation method, and the sensor is prepared by encapsulation with a sealing material. Compared with the traditional complex and cumbersome sensor preparation process, the process of the present invention is simple and easy to operate, which not only significantly reduces the production cost, but also ensures the uniformity and stability of the composite material on the substrate, and provides feasibility for large-scale industrial production; by adding a sealing material with good air permeability and high chemical stability on the surface of the sensor, the core functional layer of the sensor is effectively protected from the influence of external humidity, oxidation and other factors, and the environmental adaptability and long-term service life of the sensor are greatly improved. This design breaks through the limitations of traditional flexible temperature sensors that are susceptible to environmental interference and fast performance decay, and provides a preparation method and application of thermosensitive composite temperature sensors with technical guarantee for high-reliability smart textiles.

[0005] The method for preparing the thermosensitive composite temperature sensor of the present invention comprises the following steps: Step 1: Synthesis of MXene: Common fluoride salts are selected to react with hydrochloric acid to generate hydrofluoric acid, and the MAX phase (Ti3AlC2) is added to the hydrofluoric acid. The Al layer in the MAX phase (Ti3AlC2) is etched by hydrofluoric acid to become MXene (Ti3C2Tx). The etched MXene (Ti3C2Tx) has a negative charge on the surface, which is more likely to attract Li + , further expanding the interlayer spacing of MXene, removing by-products, dispersing the resulting precipitate in deionized water, and subjecting it to ultrasonic treatment to obtain a MXene dispersion; Step 2: Preparation of thermosensitive composite material: The thermosensitive material is dissolved in deionized water in a certain proportion to obtain a transparent solution, a certain amount of the solution is measured and slowly injected into the Mxene dispersion and continuously shaken to ensure uniformity, to obtain a thermosensitive composite material dispersion; Step 3: Preparation of thermosensitive temperature sensing yarn or fabric: The cashmere yarn or cashmere fabric is cut to a reasonable size, cleaned and dried, and the cleaned and dried cashmere yarn is immersed in the prepared thermosensitive composite material dispersion, and appropriate pressure is applied to make the thermosensitive composite material better adhere to the cashmere yarn or cashmere fabric, so as to obtain a modified cashmere yarn or cashmere fabric with good conductive properties; Step 4: Packaging of modified cashmere yarn or cashmere fabric: The modified cashmere yarn or cashmere fabric is encapsulated using a sealing material with good air permeability and high chemical stability, and the coverage is ensured to be uniform and free of bubbles. After curing, the preparation of the Mxene-based thermal-sensitive composite temperature sensor is completed.

[0006] Preferably, in step 1, by-products are removed by centrifugation.

[0007] Preferably, in the step 2, a certain amount of the solution is slowly injected into the Mxene dispersion and continuously shaken, and then the Mxene dispersion is ultrasonically treated for 10 minutes.

[0008] Preferably, the thermosensitive material includes an organic thermosensitive agent and a liquid crystal thermosensitive material; The organic thermosensitizer includes at least one of spiropyrans, substituted ethylenes, fluoranes, and triarylmethanes; The liquid crystal thermosensitive material refers to cholesteric liquid crystal. When the wavelength of the incident light is consistent with the optical wavelength of the liquid crystal, the liquid crystal displays light of a specific color, namely, selective light scattering of the liquid crystal. The pitch of the cholesteric liquid crystal is highly dependent on temperature. The wavelength of the selective light scattering changes greatly with temperature changes. When the temperature rises, the color changes from red, orange, yellow, green to purple, and when the temperature drops, it changes from purple to red.

[0009] Preferably, in step three, the cashmere yarn or cashmere fabric is cleaned with ethanol solution and deionized water, dried at 60° C. for 4 hours to complete cleaning, and then immersed in a thermosensitive composite material dispersion, immersed for 5 minutes and then dried at room temperature, and immersed 5-8 times to ensure excellent conductivity.

[0010] Preferably, the sealing material in step 4 is at least one of polyurethane (TPU) or Ecoflex silicone rubber. After being adjusted to a suitable viscosity, a scraper or special equipment is used to evenly apply the sealing material on the surface of the modified cashmere yarn or cashmere fabric to ensure full coverage and avoid bubbles or unevenness. After the application is completed, the device is placed in a suitable temperature and environment to cure for 24 hours.

[0011] Preferably, the prepared thermosensitive composite temperature sensor is stored under low-temperature dry and oxygen-isolated conditions, and the sensor is packaged in a vacuum sealed bag or container to further reduce the contact between oxygen and moisture and isolate it from the influence of the external environment.

[0012] The application of the thermosensitive composite temperature sensor of the present invention can be made into knitted hats, underwear, scarves, gloves, handbags, etc. by weaving, knitting, braiding, etc., and can be cut and applied to corresponding clothing or fabrics; It can be used for wearable thermal comfort textiles with temperature sensing function, and has great application potential in health monitoring, sports tracking, personalized medicine and other fields. For example, close-fitting clothing for the elderly or children can provide timely warning of changes in body temperature through temperature color display; competition clothing for athletes, clothing for outdoor workers or people in high-latitude areas, fashionable color-changing hats and handbags, etc.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. Applying thermosensitive composite materials to the flexible substrate of cashmere fiber takes into account both functionality and flexibility. The unique softness, ductility and adaptability of cashmere fiber enable the sensor to fit complex curved surfaces or dynamic motion scenes, meeting the flexibility and comfort requirements of smart wearable devices, thereby broadening the application scope of temperature sensors; 2. The thermosensitive composite material is coated on the flexible cashmere substrate by the dipping method, and the sensor is prepared by encapsulating it with a sealing material. Compared with the traditional complicated and cumbersome sensor preparation process, the process of the present invention is simple and easy to operate, which not only significantly reduces the production cost, but also ensures the uniformity and stability of the composite material on the substrate, providing feasibility for large-scale industrial production; 3. By adding sealing materials with good air permeability and high chemical stability to the surface of the sensor, the core functional layer of the sensor is effectively protected from external factors such as humidity and oxidation, greatly improving the environmental adaptability and long-term service life of the sensor. This design breaks through the limitations of traditional flexible temperature sensors that are easily affected by environmental interference and have fast performance degradation, and provides technical support for high-reliability smart textiles. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the thermal-sensitive composite temperature sensor prepared by the present invention; Figure 2 It is a schematic diagram of the process structure of the preparation method of the thermosensitive composite temperature sensor of the present invention. DETAILED DESCRIPTION

[0015] In order to facilitate understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0016] Example 1 like Figure 1 and Figure 2 As shown, the preparation method and application of the thermal composite temperature sensor include the following steps: Prepare MXene dispersion: take 5g Ti3AlC2 powder, add 50mL 6mol / L hydrochloric acid solution and 1.6g lithium fluoride (LiF), stir at room temperature for 24h, so that lithium fluoride reacts with hydrochloric acid to generate hydrofluoric acid to selectively etch the Al layer in Ti3AlC2. After the reaction is completed, remove by-products by centrifugation, and repeatedly wash with deionized water until the pH value is close to 6. Disperse the obtained precipitate in deionized water and ultrasonically treat for 30min to obtain a MXene dispersion with a concentration of 2g / L. Cashmere yarn with a diameter of 20 μm and a length of 15 cm was taken as a flexible substrate. It was first cleaned with an ethanol solution for 10 minutes, then rinsed with deionized water and dried at 60°C for 4 hours. Pre-cleaning was completed for use. When preparing the thermosensitive composite material, 0.5 g of spiropyran and 0.5 g of cholesteric liquid crystal were dissolved in 20 mL of deionized water, stirred until uniform, and then slowly added to the prepared 50 mL of MXene dispersion with a concentration of 2 g / L. Ultrasonic treatment was performed for 10 minutes to ensure uniform dispersion. Subsequently, the clean and dry cashmere yarn was immersed in the prepared thermosensitive composite material dispersion, taken out after each immersion for 5 minutes, and dried at room temperature. This process was repeated 6 times. After each drying, pressure was applied with a roller pressing device to enhance adhesion. Finally, a 10 wt% polyurethane (TPU) solution was evenly coated on the yarn using a scraper to ensure uniform coverage and no bubbles. It was cured at 50°C for 24 hours to prepare a highly sensitive flexible temperature sensor.

[0017] Example 2 like Figure 1 and Figure 2 As shown, the preparation method and application of the thermal composite temperature sensor include the following steps: To prepare a MXene dispersion, 5 g of Ti3AlC2 powder was mixed with 50 mL of 6 mol / L hydrochloric acid and 3 g of sodium fluoride (NaF), and stirred at room temperature for 48 h to generate hydrofluoric acid to etch the Al layer in Ti3AlC2, thereby generating Ti3C2Tx MXene nanosheets. The resulting mixture was centrifuged to remove by-products, and repeatedly washed with deionized water until the pH value was close to 6. The precipitate was redispersed in deionized water and ultrasonically treated for 30 min to obtain a MXene dispersion with a concentration of 3 g / L. A 10cm×10cm cashmere fabric with a thickness of 0.2mm was taken as a flexible substrate. It was first cleaned with an ethanol solution for 10 minutes, then rinsed with deionized water and dried at 60°C for 4 hours. The pre-cleaning was completed and set aside. When preparing the thermosensitive composite material, 0.6g of fluorane and 0.4g of triarylmethane were dissolved in 30mL of deionized water. After stirring evenly, 100mL of the prepared MXene dispersion with a concentration of 3g / L was added dropwise. Ultrasonic treatment was performed for 15 minutes to ensure uniform dispersion. Subsequently, the thermosensitive composite material was evenly covered on the surface of the cashmere fabric by the dipping method, and placed in a vacuum drying equipment and dried at 40°C for 15 minutes. The dipping was repeated 5 times to increase the thickness of the functional layer. Finally, 15wt% of Ecoflex silicone rubber was evenly coated on the surface of the cashmere fabric with a scraper and cured at 60°C for 12 hours to obtain a flexible temperature sensor.

[0018] The main functions achieved by the present invention are: 1. Applying thermosensitive composite materials to the flexible substrate of cashmere fiber takes into account both functionality and flexibility. The unique softness, ductility and adaptability of cashmere fiber enable the sensor to fit complex curved surfaces or dynamic motion scenes, meeting the flexibility and comfort requirements of smart wearable devices, thereby broadening the application scope of temperature sensors; 2. The thermosensitive composite material is coated on the flexible cashmere substrate by the dipping method, and the sensor is prepared by encapsulating it with a sealing material. Compared with the traditional complicated and cumbersome sensor preparation process, the process of the present invention is simple and easy to operate, which not only significantly reduces the production cost, but also ensures the uniformity and stability of the composite material on the substrate, providing feasibility for large-scale industrial production; 3. By adding sealing materials with good air permeability and high chemical stability to the surface of the sensor, the core functional layer of the sensor is effectively protected from external factors such as humidity and oxidation, greatly improving the environmental adaptability and long-term service life of the sensor. This design breaks through the limitations of traditional flexible temperature sensors that are easily affected by environmental interference and have fast performance degradation, and provides technical support for high-reliability smart textiles.

[0019] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a thermal composite temperature sensor, characterized in that: The following steps are involved: Step 1: Synthesis of MXene: Select common fluoride salts to react with hydrochloric acid to generate hydrofluoric acid, add the MAX phase into the hydrofluoric acid, and use the hydrofluoric acid to etch the Al layer in the MAX phase to form MXene. The etched MXene surface has a negative charge that makes it easier to attract Li + , further expanding the interlayer spacing of MXene, removing by-products, dispersing the resulting precipitate in deionized water, and subjecting it to ultrasonic treatment to obtain a MXene dispersion; Step 2: Preparation of thermosensitive composite material: The thermosensitive material is dissolved in deionized water in a certain proportion to obtain a transparent solution, a certain amount of the solution is measured and slowly injected into the Mxene dispersion and continuously shaken to ensure uniformity, to obtain a thermosensitive composite material dispersion; Step 3: Preparation of thermosensitive temperature sensing yarn or fabric: The cashmere yarn or cashmere fabric is cut to a reasonable size, cleaned and dried, and the cleaned and dried cashmere yarn is immersed in the prepared thermosensitive composite material dispersion, and appropriate pressure is applied to make the thermosensitive composite material better adhere to the cashmere yarn or cashmere fabric, so as to obtain a modified cashmere yarn or cashmere fabric with good conductive properties; Step 4: Packaging of modified cashmere yarn or cashmere fabric: The modified cashmere yarn or cashmere fabric is encapsulated using a sealing material with good air permeability and high chemical stability, and the coverage is ensured to be uniform and free of bubbles. After curing, the preparation of the Mxene-based thermal-sensitive composite temperature sensor is completed.

2. The method for preparing the thermosensitive composite temperature sensor according to claim 1, characterized in that: In the step 1, by-products are removed by centrifugation.

3. The method for preparing the thermosensitive composite temperature sensor according to claim 1, characterized in that: In the step 2, a certain amount of the solution is slowly injected into the Mxene dispersion and continuously shaken, and then the Mxene dispersion is ultrasonically treated for 10 minutes.

4. The method for preparing the thermosensitive composite temperature sensor according to claim 1, characterized in that: The thermosensitive material includes an organic thermosensitive agent and a liquid crystal thermosensitive material; The organic thermosensitizer includes at least one of spiropyrans, substituted ethylenes, fluoranes, and triarylmethanes; The liquid crystal thermosensitive material refers to cholesteric liquid crystal.

5. The method for preparing the thermosensitive composite temperature sensor according to claim 1, characterized in that: In the step 3, the cashmere yarn or cashmere fabric is cleaned with ethanol solution and deionized water, dried at 60° C. for 4 hours to complete the cleaning, and then immersed in the thermosensitive composite material dispersion, immersed for 5 minutes and then dried at room temperature, and immersed 5-8 times to ensure excellent conductivity.

6. The method for preparing the thermosensitive composite temperature sensor according to claim 1, characterized in that: The sealing material in step 4 is at least one of polyurethane or Ecoflex silicone rubber. After being adjusted to a suitable viscosity, a scraper or special equipment is used to evenly apply the sealing material on the surface of the modified cashmere yarn or cashmere fabric to ensure full coverage and avoid bubbles or unevenness. After the application is completed, the device is placed in a suitable temperature and environment for curing for 24 hours.

7. The preparation method and application of the thermosensitive composite temperature sensor according to claim 1, characterized in that: The prepared thermosensitive composite temperature sensor is stored under low-temperature dry and oxygen-isolated conditions, and the sensor is packaged in a vacuum sealed bag or container to further reduce the contact between oxygen and moisture, thereby isolating the sensor from the influence of the external environment.

8. Application of the thermal composite temperature sensor, characterized in that: The thermosensitive composite temperature sensor prepared in claim 1 can be made into wearable thermal comfort textiles with temperature sensing function by weaving, knitting, and braiding, and has great application potential in the fields of health monitoring, sports tracking, personalized medicine, etc.

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