CN114705734A - Humidity sensor and manufacturing method thereof - Google Patents

Abstract

A humidity sensor and a method for manufacturing the same, the humidity sensor includes: a base layer; an electrode layer including both poles of a capacitance of the humidity sensor; the silk fibroin humidity sensing layer is arranged between two poles of the capacitor and used as a dielectric material of the capacitor, the silk fibroin humidity sensing layer comprises silk fibroin, and a fiber structure is arranged on the surface of the silk fibroin humidity sensing layer. The fiber structure is manufactured on the surface of the silk fibroin humidity sensing layer, so that the contact area of the humidity sensor and air during working can be increased, and the sensitivity and the response speed of the humidity sensor are improved.

Description

Humidity sensor and method of making the same

technical field

The present application relates to the field of electronics, and in particular, to a humidity sensor and a manufacturing method thereof.

Background technique

Humidity sensor is used to measure the content of water vapor in the air, and can be widely used in various occasions that require humidity monitoring, control and alarm, such as meteorology, military, industry, agriculture, medical treatment, construction, household appliances and daily life.

According to different working principles, humidity sensors include resistive, capacitive, electrolyte ionic and other types. Among them, the capacitive humidity sensor has the advantages of high sensitivity, fast response speed, and easy miniaturization and integration. The dielectric layer of capacitive humidity sensor is usually made of metal oxide or polymer film. Commonly used semiconductor metal oxides include zinc oxide, aluminum oxide, etc., and polymer materials include polystyrene, polyimide, butyric acetate, and the like. Its working principle is that when the ambient humidity changes, the dielectric constant of the humidity sensitive capacitor changes, and its capacitance also changes, and the capacitance change is proportional to the relative humidity.

In recent years, great progress has been made in the research and development of humidity sensors at home and abroad. With the leakage of humidity sensors to various fields, the industry has higher and higher performance requirements for humidity sensors. For example, the industry focuses on the development of humidity sensors with faster sensitivity and response speed on the basis of cost control.

SUMMARY OF THE INVENTION

The present application provides a humidity sensor and a manufacturing method thereof, which can achieve higher detection sensitivity and faster response speed.

In a first aspect, a humidity sensor is provided, comprising: a base layer; an electrode layer, including two poles of a capacitor of the humidity sensor; In the capacitor dielectric material, the silk fibroin moisture-sensing layer includes silk fibroin, and the surface of the silk fibroin moisture-sensing layer is provided with a fibrous structure.

In the embodiments of the present application, fabricating a fibrous structure on the surface of the silk fibroin moisture-sensing layer can increase the contact area of the humidity sensor with the air during operation, thereby improving the sensitivity and response speed of the humidity sensor.

In a possible implementation manner, the fiber structure includes fiber units with diameters ranging from 1 nanometer to 100 micrometers.

In the examples of this application, the micro-nano fibrous structure is prepared on the surface of the silk fibroin film, which is used to significantly increase the specific surface area of the moisture-sensing layer, increase the water absorption/water loss rate of the moisture-sensing layer, thereby improving the capacitance response range and speed. , especially in the low humidity area, the capacitance change range can be increased several times, thereby improving the test sensitivity and response speed of the humidity sensor.

In a possible implementation manner, the molecular chain structure of at least part of the silk fibroin in the silk fibroin wet layer is a β-sheet structure in a crystalline state.

In a possible implementation manner, the molecular chain structure of more than 30% of the silk fibroin in the silk fibroin wet layer is a β-sheet structure in a crystalline state.

In a possible implementation, the silk fibroin wet layer is placed in water vapor, a small-molecule organic polar solution or its vapor for a preset period of time, so that at least part of the silk fibroin is The molecular chain structure is converted into a β-sheet structure in a crystalline state.

In the embodiment of the present application, the humidity sensor uses a silk fibroin wet layer as a dielectric material, and the silk fibroin wet layer is treated with water vapor, or soaked in a small molecule organic polar solution or its vapor for preset After a long period of time, the β-sheet structure in the treated silk fibroin moisture-sensing layer is greatly improved. Since the β-sheet structure is insoluble in water, it can reduce the bound water content in the film and increase the free water content in a humid environment. Thus, the moisture sensing efficiency of the silk fibroin moisture sensing layer is improved, or in other words, the capacitance change rate is improved, thereby improving the sensitivity of the humidity sensor.

In a possible implementation manner, the small molecule organic polar solution includes at least one of the following: anhydrous methanol, methanol solution, anhydrous ethanol, and ethanol solution.

In a second aspect, a humidity sensor is provided, comprising: a base layer; an electrode layer, including two poles of a capacitor of the humidity sensor; In the capacitor dielectric material, the silk fibroin wet layer includes silk fibroin, and the molecular chain structure of more than 20% of the silk fibroin in the silk fibroin wet layer is a β-sheet structure in a crystalline state .

In a third aspect, a method for fabricating a humidity sensor is provided, comprising: growing an electrode layer on a base layer, wherein the electrode layer includes two electrodes of the capacitance of the humidity sensor; coating silk fibroin on the electrode layer protein to generate the silk fibroin wet layer; fabricate a fibrous structure on the surface of the silk fibroin wet layer.

In a fourth aspect, a method for fabricating a humidity sensor is provided, comprising: growing an electrode layer on a base layer, wherein the electrode layer includes two electrodes of the capacitance of the humidity sensor; coating silk fibroin on the electrode layer protein to generate the silk fibroin wet layer; the silk fibroin wet layer is placed in a small molecule organic polar solution or its vapor for a preset period of time, so that more than 30% of the silk fibroin molecular chain structure into the β-sheet structure in the crystalline state.

In the examples of this application, the silk fibroin moisture-sensing layer can be treated to make the β-sheet structure in its molecular chain structure reach more than 30%. Since the β-sheet structure is insoluble in water, water molecules can interact with silk fibroin. The β-folding of the silk fibroin can be rapidly adsorbed and desorbed, which can reduce the bound water content in the film and increase the free water content in a humid environment, thereby improving the moisture-sensing efficiency of the silk fibroin moisture-sensing layer, thereby improving the humidity sensor. sensitivity.

Description of drawings

FIG. 1 is a schematic structural diagram of a humidity sensor 100 according to an embodiment of the present application;

FIG. 2 is a schematic structural diagram of a humidity sensor 100 according to another embodiment of the present application;

3 is a schematic flowchart of a manufacturing method of a humidity sensor according to an embodiment of the present application;

4 is a schematic flowchart of a manufacturing method of a humidity sensor according to another embodiment of the present application;

FIG. 5 is a schematic flowchart of a method for fabricating a humidity sensor according to another embodiment of the present application.

Detailed ways

The technical solutions in the present application will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic structural diagram of a humidity sensor 100 according to an embodiment of the present application. As shown in FIG. 1 , the humidity sensor 100 includes: a silk fibroin moisture-sensing layer, an electrode layer and a base layer. Wherein, the electrode layer includes two electrodes of the capacitor of the humidity sensor 100, and the silk fibroin moisture-sensing layer is used as a dielectric material between the two electrodes of the capacitor. The silk fibroin moisture-sensing layer can cover the middle of the two poles and on the two poles in the electrode layer.

Among them, the above-mentioned silk fibroin refers to the natural polymer fibrin extracted from silk. It has good mechanical properties and physicochemical properties, such as good flexibility and tensile strength, breathability and moisture permeability, sustained release and the like. The implementation of this application does not limit the extraction method and specific type of silk fibroin.

In some examples, the above-mentioned electrode layers may adopt the structure of interdigitated electrodes. The material of the electrode layer can be any conductive material, as an example, the material of the electrode layer can include but not limited to the following: gold, silver, gold nanowire material, silver nanowire material, graphene, indium tin oxide (ITO), etc. .

Optionally, the capacitance formed by the humidity sensor can be a horizontal flat capacitor structure, the electrode layer can adopt an interdigital electrode structure, the positive and negative electrode plates are in the same horizontal direction, and the silk fibroin moisture-sensing layer as a dielectric is filled in the fork. Refers to between the electrodes, and can be in direct contact with the outside world.

Optionally, the above-mentioned base layer may be composed of glass material or plastic material. As an example, the material of the above-mentioned base layer may include, but is not limited to, the following: polyimide (PI), polycarbonate (PC), ITO glass, glass, silicon wafer, polyethylene terephthalate ( PET) etc.

The working principle of the humidity sensor 100 is as follows: the electrodes in the electrode layer can be used as two poles of a capacitor, and the silk fibroin moisture-sensing layer can be used as a dielectric material between the capacitor plates. Humidity changes the dielectric constant of the silk fibroin wet-sensing layer, thereby changing the output capacitance. When the humidity sensor 100 is working, the humidity sensor 100 can be placed in a test environment. Changes in the moisture content in the test environment will cause fluctuations in the capacitance value, so that the humidity in the environment can be measured according to the change in the capacitance value.

In the embodiment of the present application, silk fibroin is used as the dielectric material of the capacitor in the humidity sensor 100 , and its good air and moisture permeability can be used to increase the test sensitivity of the humidity sensor 100 .

Further, in the embodiments of the present application, the silk fibroin moisture-sensing layer can be further processed to optimize its performance.

For example, the silk fibroin moisture-sensing layer can be treated to increase the β-sheet structure in the crystalline state (hereinafter referred to as β-sheet structure for brevity) in the silk fibroin moisture-sensing layer. Since the β-sheet structure is insoluble in water, In a humidity environment, the content of bound water in the film can be reduced, and the content of free water can be increased at the same time, thereby realizing the improvement of the moisture-sensing efficiency of the silk fibroin moisture-sensing layer, thereby improving the sensitivity of the humidity sensor 100 .

In some examples, the naturally extracted silk fibroin itself may also contain a certain proportion of beta sheet structure, but the proportion is lower, for example, it may be between 0 and 20%.

Optionally, some processing methods may also be adopted in the embodiments of the present application to increase the ratio of the β-sheet structure in the silk fibroin moisture-sensing layer. In some examples, the silk fibroin wet layer can be placed in an organic polar solution of small molecules or its vapor for a preset period of time to change the molecular chain structure of silk fibroin (also referred to as modification), so that the Transition from an amorphous state (Silk I) to a crystalline state (Silk II) and increase the water-insoluble β-sheet structure. Under this treatment, the proportion of the β-sheet structure in the silk fibroin wet layer can be greatly increased, for example, can be increased to more than 30%. As an example, the proportion of beta sheet structure in the silk fibroin wet layer may be 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40% , 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57 %, 58%, 59%, 60%, 65%, 70%.

In some examples, the proportion of beta sheet structures in the silk fibroin wet layer is approximately between 30% and 55%. Alternatively, as technology advances, the proportion of β-sheet structures in the silk fibroin wet-sensing layer can also be increased, for example, to more than 60%.

Optionally, the organic polar solution of the above-mentioned small molecules may include, but is not limited to, the following: anhydrous methanol, methanol solution, anhydrous ethanol, and ethanol solution.

The concentration of the organic polar solution of each of the above-mentioned small molecules can be configured according to specific conditions, as long as it can increase the β-sheet structure in silk fibroin. For example, the concentration of the above-mentioned small molecule organic polar solution may be between 5% and 90%.

In one example, the concentration of the methanol solution may be between 75% and 85%.

Optionally, the embodiments of the present application do not limit the soaking time of the silk fibroin moisture-sensing layer in the organic polar solution of small molecules, which can be determined according to specific circumstances. For example, the above soaking time may be 0.5 hours to 12 hours. For example, the above preset duration may be 1 hour, 1 hour and 30 minutes, 1 hour and 45 minutes, 2 hours, 2 hours and 15 minutes, 2 hours and 30 minutes, and 10 hours.

In one example, the silk fibroin wet layer can be soaked in a methanol solution with a concentration of 80% for 2 hours to obtain the silk fibroin wet layer after the molecular chain structure is changed.

The above silk fibroin moisture-sensing layer is obtained by immersing the protein layer in an aqueous methanol solution for a predetermined period of time to change the molecular chain structure of the protein layer.

In the embodiment of the present application, the humidity sensor 100 uses a silk fibroin moisture-sensing layer as a dielectric material, and the silk fibroin moisture-sensing layer is obtained after soaking in an organic polar solution of small molecules for a predetermined period of time. The β-sheet structure in the silk fibroin moisture-sensing layer is greatly improved. Since the β-sheet structure is insoluble in water, it can reduce the bound water content in the film and increase the free water content in a humid environment, thereby realizing the silk fibroin moisture-sensing layer. The humidity-sensing efficiency of the layer is improved, thereby improving the sensitivity of the humidity sensor.

Wherein, the above method of soaking the silk fibroin wet layer in steam or solution belongs to the dry film modification method. Optionally, in some examples, other methods can also be adopted to realize the modification of the silk fibroin wet layer. For example, adding inducers such as ethanol solution, sodium lauryl sulfate, ethylene glycol diglycidyl ether to the silk fibroin solution, or using ultrasonic, mechanical vibration, and electric field to the solution can improve the solution state. The β-sheet content, after the silk fibroin solution treated above is prepared into a film, the β-sheet content is higher than that of the film formed by the native silk fibroin.

FIG. 2 is a schematic structural diagram of a humidity sensor 100 according to another embodiment of the present application. As shown in FIG. 2 , optionally, in the embodiments of the present application, a fibrous structure may also be fabricated on the surface of the silk fibroin moisture-sensing layer. The above-mentioned fiber structure may include fiber units with a diameter ranging from 1 nanometer (nm) to 100 micrometers (μm). Optionally, the process of fabricating the fiber structure on the surface of the silk fibroin wet layer can also be referred to as a protein surface roughening process.

Optionally, in a specific example, one or more of the following processes can be used to manufacture the fiber structure: plasma oxidation etching process, electro-atomization etching process, ultrasonic atomization etching process, high pressure atomization etching process Wait.

Among them, the principle of electro-atomization etching refers to the atomization of deionized water or a mixed solution of deionized water and ethanol into micro-nano-scale droplets through the principle of electrohydrodynamic atomization, and then the droplets are deposited on silk fibroin. On the surface of the moisture-sensing layer, micro-nano structures appear on the surface of silk fibroin under the action of physical dissolution. Similar to electro-atomization etching, ultrasonic atomization and high-pressure atomization use the principle of ultrasonic or high-pressure atomization to deposit tiny droplets on the surface of silk fibroin, generate microstructures under dissolution, and increase the specific surface area of the moisture-sensitive layer .

In the examples of this application, the micro-nano fibrous structure is prepared on the surface of the silk fibroin film, which is used to significantly increase the specific surface area of the moisture-sensing layer, increase the water absorption/water loss rate of the moisture-sensing layer, thereby improving the capacitance response range and speed. , especially in the low humidity area, the capacitance change range can be increased several times, thereby improving the test sensitivity and response speed of the humidity sensor.

Among them, the specific surface area refers to the total area possessed by a unit mass of material.

In the embodiment of the present application, fabricating a fibrous structure on the surface of the silk fibroin moisture-sensing layer can increase the contact area of the humidity sensor 100 with the air during operation, thereby improving the sensitivity and response speed of the humidity sensor 100 .

FIG. 3 is a schematic flowchart of a manufacturing method of a humidity sensor according to an embodiment of the present application. As shown in FIG. 3, the manufacturing method includes the following steps.

S301 , growing an electrode layer on the base layer, where the electrode layer includes two electrodes of the capacitance of the humidity sensor.

As an example, the above-mentioned base layer may also be composed of a glass material or a plastic material. For example, PI (polyimide), PC (polycarbonate) or PET (polyethylene terephthalate) material.

The electrodes in the above-mentioned electrode layers may be interdigitated electrodes or other types of electrodes.

In some examples, the electrode layer may be fabricated using photolithography and evaporation processes.

S302 , coating silk fibroin on the electrode layer to generate a silk fibroin moisture-sensing layer.

Optionally, the above-mentioned coating of silk fibroin on the electrode layer may include, but is not limited to, the following methods: spin coating, blade coating, screen printing, slit printing, and the like.

S303, fabricating a fibrous structure on the surface of the silk fibroin moisture-sensing layer.

Optionally, in S303, at least one of the following processes is used to manufacture the fiber structure: a plasma oxidation etching process, an electro-atomization process, an ultrasonic atomization process, and a high-pressure atomization process.

Optionally, the above-mentioned fiber structure includes fiber units with diameters ranging from 1 nanometer to 100 micrometers.

Optionally, the method of FIG. 3 may further include S304.

S304, placing the silk fibroin wet layer in the small molecule organic polar solution or its vapor for a preset period of time.

Optionally, part of S304 may be performed before S303, or may be performed after S304, which may be determined according to the characteristics of the specifically adopted process, which is not limited in this embodiment of the present application.

Optionally, the organic polar solution of small molecules includes at least one of the following: anhydrous methanol, methanol solution, absolute ethanol, and ethanol solution.

Optionally, the preset duration is 0.5 to 12 hours.

In the examples of this application, a micro-nanofiber structure is prepared on the surface of the silk fibroin film, which is used to significantly increase the specific surface area of the moisture-sensing layer, increase the water absorption/water loss rate of the moisture-sensing layer, and thereby improve the capacitance response range and speed. Especially in the low humidity area, the capacitance change range can be increased several times, thereby improving the test sensitivity and response speed of the humidity sensor.

In the examples of the present application, by placing the silk fibroin wet layer in water vapor, a small molecule organic polar solution or its vapor for a preset period of time to change the molecular chain structure of the silk fibroin wet layer, it is possible to increase the The insolubility of silk fibroin-sensing wet layer in water. After the water insolubility is enhanced, water can be absorbed and lost quickly, thereby improving the test sensitivity and response speed of the humidity sensor.

In some examples, when manufacturing the humidity sensor, part S303 can be omitted, so that a humidity sensor without a fiber structure can be obtained.

In some examples, when manufacturing the humidity sensor, part S304 can be omitted, so that a humidity sensor that changes the molecular chain structure of silk fibroin can be obtained.

In some examples, when fabricating the humidity sensor, parts S303 and S304 may also be omitted.

4 and 5, the specific flow of the manufacturing method of the humidity sensor will continue to be introduced. Wherein, the fabrication method of the humidity sensor in FIG. 4 includes the steps of fabricating a fiber structure and modifying the silk fibroin moisture-sensing layer. The fabrication method of the humidity sensor in FIG. 5 includes the step of modifying the silk fibroin moisture-sensing layer.

FIG. 4 is a schematic flowchart of a manufacturing method of a humidity sensor according to another embodiment of the present application. As shown in Figure 4, the method includes the following steps.

S1. The glass is washed and dried to obtain a glass substrate 11, which is covered with an ITO layer 12.

Among them, glass can be used as the base material, and optionally, glass can be replaced by other base materials, for example, PI, PET, and the like.

S2, using a blade coater to uniformly scrape a layer of photoresist on the substrate 11 to obtain a photoresist film 13 .

S3, the substrate and the mask plate containing the reverse interdigitated electrode pattern are closely attached, and then photolithography is performed to obtain the photoresist film 14 with the interdigitated pattern.

S4, soak the substrate in ITO etching solution, the exposed ITO area without photoresist protection is etched and dissolved, and the interdigitated pattern part still has good conductivity due to the protection of the photoresist film 14 with interdigitated pattern to obtain a functionalized thin film 15 with a patterned photoresist.

S5 , soak the sample in ethanol to remove the adhesive, wash off the photoresist, rinse with deionized water, and dry with nitrogen to obtain a patterned ITO film 16 .

S6, using a blade coater to uniformly scrape a layer of silk fibroin on the ITO film 16 to obtain an intrinsic silk fibroin wet film 17.

S7, soak the sample with the silk fibroin wet film 17 in 80% methanol solution for 2 hours to obtain a modified water-insoluble silk fibroin wet layer 18.

Optionally, the above methanol solution can also be replaced by water vapor, other organic polar solutions of small molecules or their vapors, for example, absolute ethanol, ethanol solution and the like. The above soaking time can be lengthened or reduced according to practice.

S8, the nanofiber structure 19 is prepared on the surface of the silk fibroin moisture-sensing layer by means of plasma oxygen etching, so as to further improve the performance of the humidity sensor.

Optionally, the nanofiber structure 19 can also be prepared in other ways, for example, an electro-atomization process, an ultrasonic atomization process, a high-pressure atomization process, and the like.

FIG. 5 is a schematic flowchart of a method for fabricating a humidity sensor according to another embodiment of the present application. As shown in Figure 5, the method includes the following steps.

S1, washing and drying the PET to obtain a PET substrate 11 .

Alternatively, PET can be replaced by other base materials, eg, PI, PC, and the like.

S2, using a blade coater to uniformly scrape a layer of photoresist on the substrate 11 to obtain a photoresist film 12 .

S3, the substrate 11 is closely attached to the mask plate containing the interdigitated electrode pattern, and then photolithography is performed to obtain a photoresist film 13 with an interdigitated electrode pattern.

S4. Evaporate a layer of silver electrodes with a thickness of 100 nm on the surface of the patterned photoresist film 13, and deposit a uniform silver film on the interdigitated pattern part, that is, the exposed glass area without photoresist protection, to obtain a patterned light The functionalized film 14 of the resist.

S5 , soak the sample in ethanol to remove the adhesive, wash off the photoresist, rinse with deionized water, and then dry with nitrogen to obtain a patterned silver film 15 .

S6, using a knife coater to uniformly scrape a layer of silk fibroin on the silver film 15 to obtain an intrinsic silk fibroin wet film 16.

S7. Soak the sample of the silk fibroin moisture-sensing film 16 in absolute ethanol for 2 hours to obtain a modified water-insoluble silk fibroin moisture-sensing layer 17, and then obtain a silk fibroin moisture sensor.

Optionally, the above anhydrous ethanol can also be replaced by other small molecule organic polar solutions or steam, for example, ethanol solution, anhydrous methanol, methanol solution and the like. The above soaking time can be lengthened or reduced according to practice.

It should be understood that FIG. 3 to FIG. 5 are only used as an exemplary illustration of the manufacturing method of the humidity sensor. In practice, the manufacturing method may also include more or less steps, and the solution obtained by appropriate deformation still falls. into the protection scope of the embodiments of the present application.

It should be understood that the numbers of the steps in the method in the embodiments of the present application do not limit the sequence of their execution. In practical applications, the sequence of the above steps may also be adjusted according to practice, which is not limited in the embodiments of the present application.

Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Skilled artisans may implement the described functionality using different methods for each particular application, but such implementations should not be considered beyond the scope of this application.

Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the above-described systems, devices and units may refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. For example, the device embodiments described above are only illustrative. For example, the division of units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated. to another system, or some features can be ignored, or not implemented. On the other hand, the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, indirect coupling or communication connection of devices or units, and may be in electrical, mechanical or other forms.

Units described as separate components may or may not be physically separated, and components shown as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution in this embodiment.

In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit.

The functions, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be embodied in the form of a software product in essence, or the part that contributes to the prior art or the part of the technical solution. The computer software product is stored in a storage medium, including Several instructions are used to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods of the various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), magnetic disk or optical disk and other media that can store program codes .

The above are only specific embodiments of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, and should cover within the scope of protection of this application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (18)

1. a humidity sensor, is characterized in that, comprises: basal layer; an electrode layer, including two poles of the capacitance of the humidity sensor; The silk fibroin moisture-sensing layer is arranged between the two poles of the capacitor and is used as the dielectric material of the capacitor. The silk fibroin moisture-sensing layer includes silk fibroin, and the silk fibroin moisture-sensing layer The surface is provided with a fibrous structure. 2 . The humidity sensor of claim 1 , wherein the fiber structure comprises fiber units with diameters ranging from 1 nanometer to 100 micrometers. 3 . The humidity sensor according to claim 1 or 2, wherein the molecular chain structure of at least part of the silk fibroin in the silk fibroin moisture-sensing layer is a β-sheet structure in a crystalline state. 4 . The humidity sensor according to claim 1 , wherein more than 30% of the silk fibroin moisture-sensing layer in the silk fibroin moisture-sensing layer has a molecular chain structure of a β-sheet structure in a crystalline state. 5 . 5. The humidity sensor according to claim 1 or 2, wherein the silk fibroin moisture-sensing layer is made by placing silk fibroin in a small-molecule organic polar solution or its vapor for a preset period of time, so that It is obtained by converting at least part of the molecular chain structure of silk fibroin into a β-sheet structure in a crystalline state. 6. The humidity sensor of claim 5, wherein the organic polar solution of small molecules comprises at least one of the following: Anhydrous methanol, methanol solution, absolute ethanol, ethanol solution. 7. A humidity sensor, characterized in that, comprising: basal layer; an electrode layer, including two poles of the capacitance of the humidity sensor; The silk fibroin moisture-sensing layer is arranged between the two poles of the capacitor and is used as the dielectric material of the capacitor. The silk fibroin moisture-sensing layer includes silk fibroin, and the silk fibroin moisture-sensing layer More than 30% of the molecular chain structure of silk fibroin is the β-sheet structure in the crystalline state. 8 . The humidity sensor according to claim 7 , wherein the silk fibroin moisture-sensing layer is formed by placing silk fibroin in water vapor, a small molecule organic polar solution or its vapor for a preset period of time, to It is obtained by converting at least part of the molecular chain structure of silk fibroin into a β-sheet structure in a crystalline state. 9 . The humidity sensor according to claim 8 , wherein the organic polar solution of small molecules comprises at least one of the following: anhydrous methanol, methanol solution, anhydrous ethanol, and ethanol solution. 10 . 10. A method of making a humidity sensor, comprising: growing an electrode layer on the base layer, the electrode layer including two poles of the capacitance of the humidity sensor; Coating silk fibroin on the electrode layer to generate the silk fibroin wet layer; A fibrous structure is produced on the surface of the silk fibroin moisture-sensing layer. 11. The method of claim 10, wherein the fabricating the fiber structure on the surface of the silk fibroin moisture-sensing layer comprises: using at least one of the following processes to fabricate the fiber structure: plasma Oxidation etching process, electro atomization etching process, ultrasonic atomization etching process, high pressure atomization etching process. 12. The manufacturing method according to claim 10 or 11, wherein the fiber structure comprises fiber units with a diameter ranging from 1 nanometer to 100 micrometers. 13. The manufacturing method according to claim 10 or 11, wherein the method further comprises: placing the silk fibroin wet layer in water vapor, a small molecule organic polar solution or its vapor for a preset time period , so that at least part of the molecular chain structure of silk fibroin is transformed into a β-sheet structure in a crystalline state. 14. The manufacturing method of claim 13, wherein the organic polar solution of the small molecule comprises at least one of the following: Anhydrous methanol, methanol solution, absolute ethanol, ethanol solution. 15 . The manufacturing method according to claim 13 , wherein the preset duration is 0.5-12 hours. 16 . 16 . The preparation method according to claim 13 , wherein the organic polar solution of the small molecule is a methanol solution, and the methanol concentration of the methanol solution is 75% to 85%. 17 . 17. A method for making a humidity sensor, comprising: growing an electrode layer on the base layer, the electrode layer including two poles of the capacitance of the humidity sensor; Coating silk fibroin on the electrode layer to generate the silk fibroin wet layer; The silk fibroin wet layer is placed in water vapor, a small molecule organic polar solution or its vapor for a preset period of time, so that more than 30% of the silk fibroin molecular chain structure is converted into a β-sheet structure in a crystalline state. 18. The method of claim 17, wherein the organic polar solution of small molecules comprises at least one of the following: anhydrous methanol, methanol solution, anhydrous ethanol, and ethanol solution.

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