Humidity sensitive material and preparation method of humidity sensitive device

Abstract

The invention discloses a humidity sensitive material and a preparation method of a humidity sensitive device. In the invention, the temperature-responsive polymer microspheres endow the humidity-sensitive material with additional intelligent response characteristics. The microspheres have unique temperature sensitivity and can generate volume phase change in a specific temperature range, so that the overall performance of the material is influenced. When the environment temperature changes, the microspheres can absorb or release heat, so that the volume of the microspheres is expanded or contracted, and the volume change is further transmitted to the humidity sensitive material, so that the humidity sensitive material responds to the temperature change. The humidity response and the temperature response with the dual response characteristics enable the material to more accurately monitor and adjust the humidity under complex environmental conditions, and the intelligent level of the material is improved. Meanwhile, due to the introduction of the microspheres, the processability and the forming effect of the material are improved, so that the humidity sensitive elements with various shapes and sizes can be prepared more easily.

Description

Technical Field

[0001] The present invention belongs to the technical field of humidity sensitive materials, and in particular relates to a method for preparing a humidity sensitive material and a humidity sensitive device. Background Art

[0002] Humidity sensitive materials refer to a class of special materials that can respond to changes in humidity in the external environment. They have the characteristics of significant changes in physical or chemical properties under different humidity conditions. Such materials are widely used in sensors, smart textiles, moisture-proof packaging, humidity control and other fields. Common humidity sensitive materials include hygroscopic polymers, humidity sensitive ceramics, humidity sensing powders, etc. The working principle of these materials is usually based on the physical process of hygroscopic expansion or dehumidification contraction, or through humidity-induced chemical reactions inside the material to achieve functions. Due to their unique humidity-sensitive properties, humidity sensitive materials play an important role in ensuring product quality, improving people's living environment and developing new intelligent systems.

[0003] However, traditional humidity-sensitive materials mainly rely on a single humidity response mechanism, which often has disadvantages such as slow response speed, low precision, and poor stability. These materials usually lack the ability to adapt to complex environmental factors, such as the interference of temperature changes on humidity response, which limits their application scope and effect. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a humidity sensitive material and a humidity sensitive device in order to solve the above-mentioned problem.

[0005] The technical solution adopted by the present invention is as follows: a humidity sensitive material, the material comprising: Nanopolymer Matrix: Nanocellulose: 20-30 parts by weight; Nano silicon dioxide: 5-15 parts by weight; Biological moisture sensitive components: Chitosan: 10-20 parts by weight; Sodium alginate: 5-15 parts by weight; Smart Responsive Composition: Acrylamide-acrylic acid copolymer: 5-15 parts by weight; Temperature responsive polymer microspheres: 3-7 parts by weight; Plasticizers and compatibilizers: 1,2-propylene glycol: 3-7 parts by weight; Compatibilizer: 1-3 parts by weight; Crosslinking agent: Epichlorohydrin: 0.5-1.5 parts by weight; Nanodispersants: Phosphate dispersant: 0.5-1.5 parts by weight; Functional additives: Conductive carbon nanotubes: 1-3 parts by weight; Antifungal and antibacterial agent: 0.5-1.5 parts by weight.

[0006] In a preferred embodiment, the temperature-responsive polymer microspheres include: monomer N-isopropyl acrylamide, cross-linking agent N,N'-methylenebisacrylamide, initiator ammonium persulfate, dispersant polyvinyl alcohol or sodium dodecyl sulfate and solvent deionized water; The preparation process of the temperature-responsive polymer microspheres comprises: a. Solution preparation: Prepare NIPAM monomer solution: dissolve NIPAM in deionized water, the concentration is generally 10%~20% (w / v); prepare crosslinker solution: dissolve MBA in deionized water, the concentration is generally 1%~5% (w / v); prepare initiator solution: dissolve APS in deionized water, the concentration is generally 0.1%~0.5% (w / v); prepare dispersant solution: dissolve PVA or SDS in deionized water, and adjust the concentration as needed.

[0007] b. Microsphere synthesis: Mix the NIPAM monomer solution, crosslinker solution and dispersant solution and stir evenly. Add the initiator solution and stir rapidly to form a uniform prepolymer solution. Pour the prepolymer solution into a hot oil bath or water bath and control the temperature at 70-80°C for free radical polymerization. After 3 hours of reaction, PNIPAM microspheres are formed.

[0008] c. Microsphere separation and purification: After the reaction is completed, cool to room temperature and separate the PNIPAM microspheres using a centrifuge. Wash the microspheres with deionized water several times to remove unreacted monomers and impurities. Re-disperse the washed microspheres in deionized water to obtain a pure PNIPAM microsphere suspension.

[0009] In a preferred embodiment, the preparation method comprises the following steps: S1: Surface modification of nanocellulose and nanosilica to improve their dispersibility in the polymer matrix; S2: mixing the modified nanocellulose and nanosilica, adding an appropriate amount of solvent and stirring to form a uniform nanopolymer matrix suspension; S3: gradually adding chitosan and sodium alginate to the above suspension, and continuously stirring until completely dissolved and evenly distributed; S4: gradually adding acrylamide-acrylic acid copolymer and temperature-responsive polymer microspheres to the mixed solution, and continuing to stir to ensure uniform mixing; S5: Add 1,2-propylene glycol and a compatibilizer to the mixed solution and stir evenly to improve the processing performance and compatibility of the material; S6: Add epichlorohydrin as a cross-linking agent and a phosphate dispersant, and stir evenly to promote the cross-linking reaction and the dispersion of the nanomaterial; S7: pouring the mixed liquid into a mold for molding, followed by post-processing steps such as drying and curing to obtain the final moisture-sensitive material.

[0010] In a preferred embodiment, in step S1, the pretreatment is specifically performed as follows: dispersing the nanocellulose in an ethanol solution, adding an appropriate amount of silane coupling agent, ultrasonically treating for 30 minutes, then placing in a 60°C water bath and stirring for 2 hours, and finally centrifugally washing and drying to obtain modified nanocellulose. For nanosilica, aminopropyltriethoxysilane is used for surface modification to improve its dispersibility and hydrophilicity.

[0011] In a preferred embodiment, in the step S2, the modified nanocellulose and nano silicon dioxide are mixed according to the ratio of NFC: SiO2 = 2: 1, an appropriate amount of deionized water is added as a solvent, and a high-speed disperser is used to stir for 30 minutes at a speed of 1000-1500rpm to form a uniform suspension. In order to further ensure the uniform dispersion of the nanomaterial, an ultrasonic disperser can be used to ultrasonically treat the suspension, and the ultrasonic power is set to 200-300W, and the processing time is 10 to 15 minutes. Through such a mixing process, it can be ensured that the nano polymer matrix has good dispersibility and uniformity, laying a solid foundation for subsequent steps.

[0012] In a preferred embodiment, in step S3, sodium alginate is slowly added to deionized water while stirring until it is completely dissolved to form a 2% to 4% sodium alginate solution. Subsequently, the two solutions are gradually added to the nanopolymer matrix suspension in a ratio of chitosan solution: sodium alginate solution = 1:1, and a magnetic stirrer is used to continuously stir at a speed of 500-700 rpm for 1-2 hours to ensure that the biological moisture sensitive component is fully mixed and evenly distributed with the nanopolymer matrix.

[0013] In a preferred embodiment, in step S4, first, acrylamide-acrylic acid copolymer is dissolved in deionized water to prepare a 5% to 10% solution. Then, the temperature-responsive polymer microspheres are dispersed in deionized water and ultrasonically treated for 10 to 15 minutes to form a uniform dispersion. The two solutions are then gradually added to the above-mentioned mixed solution according to the ratio of acrylamide-acrylic acid copolymer solution: temperature-responsive polymer microsphere dispersion = 2:1, and stirred at a speed of 1000-1500rpm for 30 minutes using a high-speed disperser.

[0014] In a preferred embodiment, in step S5, 1,2-propylene glycol is first taken as a plasticizer, and slowly added to the mixed solution at a ratio of 5% to 10% of the total mass of the mixed solution, stirring while adding until completely dissolved. Then, a compatibilizer is added at a ratio of 1% to 3% of the total mass of the mixed solution, and stirring is continued for 30 minutes to ensure that the plasticizer and the compatibilizer are fully mixed with the mixed solution. The stirring speed is controlled at 500-700rpm and the temperature is maintained at room temperature. By adding plasticizers and compatibilizers, the flexibility, processing performance and compatibility of the material can be effectively improved.

[0015] In a preferred embodiment, in step S6, first take epichlorohydrin as a cross-linking agent, slowly add it to the mixed solution at a ratio of 0.5% to 1.5% of the total mass of the mixed solution, stir while adding, control the stirring speed at 500-700rpm, and continue stirring for 30 minutes. Then, add a phosphate dispersant at a ratio of 0.5% to 1.5% of the total mass of the mixed solution, continue stirring for 30 minutes, and ensure that the cross-linking agent and dispersant are fully mixed with the mixed solution. In this step, it can be appropriately heated to 40-50°C to promote the cross-linking reaction. Through cross-linking and dispersion treatment, a stable cross-linked network structure can be formed to improve the mechanical properties and moisture sensitivity of the material.

[0016] In a preferred embodiment, in the step S7, first, the cross-linked and dispersed mixed solution is poured into a pre-prepared mold, and the material of the mold can be polytetrafluoroethylene (PTFE) or silicone rubber to facilitate demolding. Bubbles should be avoided during the pouring process, and bubbles can be removed by vibrating or gently tapping the mold. Then, the mold is placed at room temperature and left to stand for 24 hours to allow the material to initially solidify. Next, the mold is transferred to an oven for heat treatment, and the oven temperature is set to 60-80°C for 24-48 hours to ensure that the material is completely cured and forms a stable structure. After the heat treatment is completed, the mold is removed from the oven, and after it is cooled to room temperature, the demolding operation is performed to obtain a molded humidity-sensitive material.

[0017] After demoulding, the material is post-processed, including surface grinding and cleaning. Surface grinding can be done with sandpaper or a polisher to remove surface unevenness and impurities and improve the surface finish of the material. Deionized water or ethanol is used for cleaning to remove residues and impurities on the surface of the material. Finally, the cleaned material is placed in a drying oven and dried at a temperature of 40-50°C for 24 hours to ensure that the moisture inside the material is completely evaporated and reaches the best use state.

[0018] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. In the present invention, the acrylamide-acrylic acid copolymer ensures the excellent performance of the material in terms of humidity response. This copolymer has a high degree of water solubility and hygroscopicity, and can quickly absorb moisture in the environment, resulting in significant changes in its volume and morphology. As the ambient humidity decreases, the copolymer can release the absorbed moisture and return to its initial state. This property enables the humidity-sensitive material to achieve a rapid and accurate response to changes in ambient humidity. In addition, the introduction of the acrylamide-acrylic acid copolymer also improves the mechanical strength and durability of the material, allowing it to maintain stable performance under various environmental conditions.

[0019] 2. In the present invention, temperature-responsive polymer microspheres give humidity-sensitive materials additional intelligent response characteristics. These microspheres have unique temperature sensitivity and can undergo volume phase changes within a specific temperature range, thereby affecting the overall performance of the material. When the ambient temperature changes, the microspheres absorb or release heat, causing their volume to expand or contract. This volume change is further transmitted to the humidity-sensitive material, causing it to respond to temperature changes. This dual response characteristic of humidity response and temperature response enables the material to more accurately monitor and adjust humidity under complex environmental conditions, improving the intelligence level of the material. At the same time, the introduction of microspheres also improves the processing performance and molding effect of the material, making it easier to prepare humidity-sensitive elements of various shapes and sizes. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a flow chart of the preparation method of the present invention. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Example

[0022] Reference Figure 1 , A humidity sensitive material, comprising: Nanopolymer Matrix: Nanocellulose: 20 parts by weight; Nano silicon dioxide: 5 parts by weight; Biological moisture sensitive components: Chitosan: 10 parts by weight; Sodium alginate: 5 parts by weight; Smart Responsive Composition: Acrylamide-acrylic acid copolymer: 5 parts by weight; Temperature responsive polymer microspheres: 3 parts by weight; Plasticizers and compatibilizers: 1,2-Propanediol: 3 parts by weight; Compatibilizer: 1 part by weight; Crosslinking agent: Epichlorohydrin: 0.5 parts by weight; Nanodispersants: Phosphate dispersant: 0.5 parts by weight; Functional additives: Conductive carbon nanotubes: 1 part by weight; Antifungal and antibacterial agent: 0.5 parts by weight.

[0023] 2. A humidity sensitive material according to claim 1, characterized in that: the temperature responsive polymer microspheres comprise: monomer N-isopropyl acrylamide, crosslinking agent N,N'-methylenebisacrylamide, initiator ammonium persulfate, dispersant polyvinyl alcohol or sodium dodecyl sulfate and solvent deionized water; The preparation process of the temperature-responsive polymer microspheres comprises: a. Solution preparation: Prepare NIPAM monomer solution: dissolve NIPAM in deionized water, the concentration is generally 10%~20% (w / v); prepare crosslinker solution: dissolve MBA in deionized water, the concentration is generally 1%~5% (w / v); prepare initiator solution: dissolve APS in deionized water, the concentration is generally 0.1%~0.5% (w / v); prepare dispersant solution: dissolve PVA or SDS in deionized water, and adjust the concentration as needed.

[0024] b. Microsphere synthesis: Mix the NIPAM monomer solution, crosslinker solution and dispersant solution and stir evenly. Add the initiator solution and stir rapidly to form a uniform prepolymer solution. Pour the prepolymer solution into a hot oil bath or water bath and control the temperature at 70-80°C for free radical polymerization. After 3 hours of reaction, PNIPAM microspheres are formed.

[0025] c. Microsphere separation and purification: After the reaction is completed, cool to room temperature and separate the PNIPAM microspheres using a centrifuge. Wash the microspheres with deionized water several times to remove unreacted monomers and impurities. Re-disperse the washed microspheres in deionized water to obtain a pure PNIPAM microsphere suspension.

[0026] The preparation method comprises the following steps: S1: Surface modification of nanocellulose and nanosilica to improve their dispersibility in the polymer matrix; S2: mixing the modified nanocellulose and nanosilica, adding an appropriate amount of solvent and stirring to form a uniform nanopolymer matrix suspension; S3: gradually adding chitosan and sodium alginate to the above suspension, and continuously stirring until completely dissolved and evenly distributed; S4: gradually adding acrylamide-acrylic acid copolymer and temperature-responsive polymer microspheres to the mixed solution, and continuing to stir to ensure uniform mixing; S5: Add 1,2-propylene glycol and a compatibilizer to the mixed solution and stir evenly to improve the processing performance and compatibility of the material; S6: Add epichlorohydrin as a cross-linking agent and a phosphate dispersant, and stir evenly to promote the cross-linking reaction and the dispersion of the nanomaterial; S7: pouring the mixed liquid into a mold for molding, followed by post-processing steps such as drying and curing to obtain the final moisture-sensitive material.

[0027] In step S1, the pretreatment is specifically performed as follows: dispersing the nanocellulose in an ethanol solution, adding an appropriate amount of silane coupling agent, ultrasonically treating for 30 minutes, then placing in a 60°C water bath and stirring for 2 hours, and finally centrifugally washing and drying to obtain modified nanocellulose. For nanosilica, aminopropyltriethoxysilane is used for surface modification to improve its dispersibility and hydrophilicity.

[0028] In the step S2, the modified nanocellulose and nano silicon dioxide are mixed according to the ratio of NFC: SiO2 = 2: 1, an appropriate amount of deionized water is added as a solvent, and a high-speed disperser is used to stir for 30 minutes at a speed of 1000-1500rpm to form a uniform suspension. In order to further ensure the uniform dispersion of the nanomaterial, an ultrasonic disperser can be used to ultrasonically treat the suspension, and the ultrasonic power is set to 200-300W, and the processing time is 10 to 15 minutes. Through such a mixing process, it can be ensured that the nano polymer matrix has good dispersibility and uniformity, laying a solid foundation for subsequent steps.

[0029] In step S3, sodium alginate is slowly added to deionized water while stirring until it is completely dissolved to form a 2% to 4% sodium alginate solution. Subsequently, the two solutions are gradually added to the nanopolymer matrix suspension in a ratio of chitosan solution: sodium alginate solution = 1:1, and a magnetic stirrer is used to continuously stir at a speed of 500-700 rpm for 1-2 hours to ensure that the biological moisture sensitive component is fully mixed and evenly distributed with the nanopolymer matrix.

[0030] In the step S4, first, acrylamide-acrylic acid copolymer is dissolved in deionized water to prepare a 5% to 10% solution. Then, the temperature-responsive polymer microspheres are dispersed in deionized water and ultrasonically treated for 10 to 15 minutes to form a uniform dispersion. Then, the two solutions are gradually added to the above-mentioned mixed solution according to the ratio of acrylamide-acrylic acid copolymer solution: temperature-responsive polymer microsphere dispersion = 2:1, and stirred at a speed of 1000-1500rpm for 30 minutes using a high-speed disperser.

[0031] In the step S5, 1,2-propylene glycol is first taken as a plasticizer, and slowly added to the mixed solution at a ratio of 5% to 10% of the total mass of the mixed solution, stirring while adding until completely dissolved. Then, a compatibilizer is added at a ratio of 1% to 3% of the total mass of the mixed solution, and stirring is continued for 30 minutes to ensure that the plasticizer and the compatibilizer are fully mixed with the mixed solution. The stirring speed is controlled at 500-700rpm, and the temperature is maintained at room temperature. By adding plasticizers and compatibilizers, the flexibility, processing performance and compatibility of the material can be effectively improved.

[0032] In the step S6, first take epichlorohydrin as a cross-linking agent, and slowly add it to the mixed solution at a ratio of 0.5% to 1.5% of the total mass of the mixed solution, stir while adding, control the stirring speed at 500-700rpm, and continue stirring for 30 minutes. Then, add a phosphate dispersant at a ratio of 0.5% to 1.5% of the total mass of the mixed solution, and continue stirring for 30 minutes to ensure that the cross-linking agent and dispersant are fully mixed with the mixed solution. In this step, it can be appropriately heated to 40-50°C to promote the cross-linking reaction. Through cross-linking and dispersion treatment, a stable cross-linked network structure can be formed to improve the mechanical properties and moisture sensitivity of the material. In the step S7, first, pour the cross-linked and dispersed mixed solution into a pre-prepared mold, and the material of the mold can be polytetrafluoroethylene (PTFE) or silicone rubber to facilitate demolding. Bubbles should be avoided during the pouring process, and bubbles can be removed by vibrating or gently tapping the mold. Then, the mold is placed at room temperature for 24 hours to allow the material to initially solidify. Next, the mold is transferred to an oven for heat treatment, and the oven temperature is set to 60-80°C for 24-48 hours to ensure that the material is fully cured and forms a stable structure. After the heat treatment is completed, the mold is removed from the oven, and after it is cooled to room temperature, the demolding operation is performed to obtain a molded humidity-sensitive material.

[0033] After demoulding, the material is post-processed, including surface grinding and cleaning. Surface grinding can be done with sandpaper or a polisher to remove surface unevenness and impurities and improve the surface finish of the material. Deionized water or ethanol is used for cleaning to remove residues and impurities on the surface of the material. Finally, the cleaned material is placed in a drying oven and dried at a temperature of 40-50°C for 24 hours to ensure that the moisture inside the material is completely evaporated and reaches the best use state.

[0034] A method for preparing a humidity sensitive device, wherein the method uses the humidity sensitive material described in the above embodiment to prepare the humidity sensitive device.

[0035] From the above, it can be seen that in the present invention, the acrylamide-acrylic acid copolymer ensures the excellent performance of the material in terms of humidity response. This copolymer has a high water solubility and hygroscopicity, and can quickly absorb moisture in the environment, resulting in significant changes in its volume and morphology. As the ambient humidity decreases, the copolymer can release the absorbed moisture and return to its initial state. This property enables the humidity-sensitive material to achieve a rapid and accurate response to changes in ambient humidity. In addition, the introduction of the acrylamide-acrylic acid copolymer also improves the mechanical strength and durability of the material, allowing it to maintain stable performance under various environmental conditions.

[0036] In the present invention, temperature-responsive polymer microspheres give humidity-sensitive materials additional intelligent response characteristics. These microspheres have unique temperature sensitivity and can undergo volume phase changes within a specific temperature range, thereby affecting the overall performance of the material. When the ambient temperature changes, the microspheres absorb or release heat, causing their volume to expand or contract. This volume change is further transmitted to the humidity-sensitive material, causing it to respond to temperature changes. This dual response characteristic of humidity response and temperature response enables the material to more accurately monitor and adjust humidity under complex environmental conditions, improving the intelligence level of the material. At the same time, the introduction of microspheres also improves the processing performance and molding effect of the material, making it easier to prepare humidity-sensitive elements of various shapes and sizes.

[0037] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0038] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A humidity sensitive material, characterized in that: The materials include: Nanopolymer Matrix: Nanocellulose: 20-30 parts by weight; Nano silicon dioxide: 5-15 parts by weight; Biological moisture sensitive components: Chitosan: 10-20 parts by weight; Sodium alginate: 5-15 parts by weight; Smart Responsive Composition: Acrylamide-acrylic acid copolymer: 5-15 parts by weight; Temperature responsive polymer microspheres: 3-7 parts by weight; Plasticizers and compatibilizers: 1,2-propylene glycol: 3-7 parts by weight; Compatibilizer: 1-3 parts by weight; Crosslinking agent: Epichlorohydrin: 0.5-1.5 parts by weight; Nanodispersants: Phosphate dispersant: 0.5-1.5 parts by weight; Functional additives: Conductive carbon nanotubes: 1-3 parts by weight; Antifungal and antibacterial agent: 0.5-1.5 parts by weight.

2. A humidity sensitive material according to claim 1, characterized in that: The temperature-responsive polymer microspheres include: monomer N-isopropyl acrylamide, cross-linking agent N,N'-methylenebisacrylamide, initiator ammonium persulfate, dispersant polyvinyl alcohol or sodium dodecyl sulfate and solvent deionized water; The preparation process of the temperature-responsive polymer microspheres comprises: a. Solution preparation: Prepare NIPAM monomer solution: dissolve NIPAM in deionized water, the concentration is generally 10% to 20% (w / v); prepare crosslinker solution: dissolve MBA in deionized water, the concentration is generally 1% to 5% (w / v); prepare initiator solution: dissolve APS in deionized water, the concentration is generally 0.1% to 0.5% (w / v); prepare dispersant solution: dissolve PVA or SDS in deionized water, and adjust the concentration as needed; b. Microsphere synthesis: NIPAM monomer solution, crosslinker solution and dispersant solution are mixed and stirred evenly; the initiator solution is added and stirred rapidly to form a uniform prepolymer solution; the prepolymer solution is poured into a hot oil bath or a water bath, the temperature is controlled at 70-80 ° C, and a free radical polymerization reaction is carried out; after reacting for 3 hours, PNIPAM microspheres are formed; c. Microsphere separation and purification: After the reaction is completed, cool to room temperature and separate the PNIPAM microspheres using a centrifuge; wash the microspheres with deionized water for multiple times to remove unreacted monomers and impurities; and redisperse the washed microspheres in deionized water to obtain a pure PNIPAM microsphere suspension.

3. The method for preparing a humidity sensitive material according to claim 1, characterized in that: The preparation method comprises the following steps: S1: Surface modification of nanocellulose and nanosilica to improve their dispersibility in the polymer matrix; S2: mixing the modified nanocellulose and nanosilica, adding an appropriate amount of solvent and stirring to form a uniform nanopolymer matrix suspension; S3: gradually adding chitosan and sodium alginate to the above suspension, and continuously stirring until completely dissolved and evenly distributed; S4: gradually adding acrylamide-acrylic acid copolymer and temperature-responsive polymer microspheres to the mixed solution, and continuing to stir to ensure uniform mixing; S5: Add 1,2-propylene glycol and a compatibilizer to the mixed solution and stir evenly to improve the processing performance and compatibility of the material; S6: Add epichlorohydrin as a cross-linking agent and a phosphate dispersant, and stir evenly to promote the cross-linking reaction and the dispersion of the nanomaterial; S7: pouring the mixed liquid into a mold for molding, followed by drying and curing post-processing steps to obtain the final moisture-sensitive material.

4. The method for preparing a humidity sensitive material and a humidity sensitive device according to claim 1, characterized in that: In step S1, the specific operation of the pretreatment is: dispersing the nanocellulose in an ethanol solution, adding an appropriate amount of silane coupling agent, ultrasonically treating for 30 minutes, then placing it in a 60° C. water bath and stirring for 2 hours, finally centrifuging and washing, and drying to obtain modified nanocellulose; for nanosilica, aminopropyltriethoxysilane is used for surface modification to improve its dispersibility and hydrophilicity.

5. The method for preparing a humidity sensitive material and a humidity sensitive device according to claim 1, characterized in that: In the step S2, the modified nanocellulose and nano-silicon dioxide are mixed in a ratio of NFC:SiO2 = 2:1, an appropriate amount of deionized water is added as a solvent, and a high-speed disperser is used to stir at a speed of 1000-1500 rpm for 30 minutes to form a uniform suspension; in order to further ensure the uniform dispersion of the nanomaterial, an ultrasonic disperser is used to perform ultrasonic treatment on the suspension, the ultrasonic power is set to 200-300 W, and the treatment time is 10 to 15 minutes.

6. The method for preparing a humidity sensitive material and a humidity sensitive device according to claim 1, characterized in that: In the step S3, sodium alginate is slowly added to deionized water while stirring until it is completely dissolved to form a 2% to 4% sodium alginate solution; then, the two solutions are gradually added to the above-mentioned nanopolymer matrix suspension in a ratio of chitosan solution: sodium alginate solution = 1:1, and a magnetic stirrer is used to continuously stir at a speed of 500-700 rpm for 1-2 hours to ensure that the biological moisture sensitive component and the nanopolymer matrix are fully mixed and evenly distributed.

7. The method for preparing a humidity sensitive material and a humidity sensitive device according to claim 1, characterized in that: In the step S4, first, acrylamide-acrylic acid copolymer is dissolved in deionized water to prepare a 5% to 10% solution; then, the temperature-responsive polymer microspheres are dispersed in deionized water and ultrasonically treated for 10 to 15 minutes to form a uniform dispersion; then, the two solutions are gradually added to the above-mentioned mixed solution according to the ratio of acrylamide-acrylic acid copolymer solution: temperature-responsive polymer microsphere dispersion = 2:1, and stirred for 30 minutes using a high-speed disperser at a speed of 1000-1500 rpm.

8. The method for preparing a humidity sensitive material and a humidity sensitive device according to claim 1, characterized in that: In the step S5, 1,2-propylene glycol is first taken as a plasticizer, and is slowly added to the mixed solution at a ratio of 5% to 10% of the total mass of the mixed solution, and stirred while adding until it is completely dissolved; then, a compatibilizer is added at a ratio of 1% to 3% of the total mass of the mixed solution, and stirring is continued for 30 minutes to ensure that the plasticizer and the compatibilizer are fully mixed with the mixed solution; the stirring speed is controlled at 500-700 rpm, and the temperature is maintained at room temperature.

9. The method for preparing a humidity sensitive material and a humidity sensitive device according to claim 1, characterized in that: In the step S6, first, epichlorohydrin is taken as a cross-linking agent, and is slowly added to the mixed solution at a ratio of 0.5% to 1.5% of the total mass of the mixed solution, while stirring, the stirring speed is controlled at 500-700 rpm, and stirring is continued for 30 minutes; then, a phosphate dispersant is added at a ratio of 0.5% to 1.5% of the total mass of the mixed solution, and stirring is continued for 30 minutes to ensure that the cross-linking agent and the dispersant are fully mixed with the mixed solution; in this step, heating is performed to 40-50° C. to promote the cross-linking reaction; In the step S7, first, the mixed solution that has been cross-linked and dispersed is poured into a pre-prepared mold, the material of the mold is polytetrafluoroethylene (PTFE) or silicone rubber, so as to facilitate demolding; bubbles should be avoided during the pouring process, and the bubbles can be removed by vibrating or gently tapping the mold; Then, the mold is placed at room temperature for 24 hours to allow the material to initially solidify; next, the mold is transferred to an oven for heat treatment, and the oven temperature is set to 60-80°C for 24-48 hours to ensure that the material is completely solidified and forms a stable structure; after the heat treatment is completed, the mold is taken out of the oven and demolded after it is cooled to room temperature to obtain a molded humidity-sensitive material; After demoulding, the material is post-processed, including surface grinding and cleaning; surface grinding is performed using sandpaper or a polishing machine to remove surface unevenness and impurities and improve the surface finish of the material; deionized water or ethanol is used for cleaning to remove residues and impurities on the surface of the material; finally, the cleaned material is placed in a drying oven and dried at a temperature of 40-50°C for 24 hours to ensure that the moisture inside the material is completely evaporated to achieve the best use state.

10. A method for preparing a humidity sensitive device, characterized in that: The preparation method uses the humidity sensitive material as described in any one of claims 1 to 2 to prepare a humidity sensitive device.

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