Preparation method and application of a high-crystallinity cellulose piezoelectric film and a sensor thereof

Abstract

This invention relates to the field of artificial intelligence sensor fabrication technology, specifically to a method for preparing a highly crystalline cellulose piezoelectric membrane and its sensor, and its application. The method includes: pretreating the raw materials of the cellulose piezoelectric membrane to obtain a first material; placing the first material in an organic alkali solution and subjecting it to ultrasound to obtain a second material; and drying the second material to obtain the cellulose piezoelectric membrane. This invention uses renewable waste fruit and vegetable peels as raw materials and obtains the membrane through organic alkali-assisted ultrasonic vibration technology. Under the synergistic effect of a mild organic alkali and ultrasound, localized glycosidic bond breakage and preferential hydrolysis occur in the hemicellulose and amorphous regions of cellulose in the fruit and vegetable peels, achieving microstructural reorganization. This significantly improves crystallinity, resulting in a more orderly stacking of elongated crystalline fibers within the cellulose layers and an increased number of asymmetric dipoles. This achieves controllable crystalline region strengthening and structural optimization, greatly activating the piezoelectric effect of the cellulose piezoelectric membrane and enhancing the sensor's sensitivity.

Description

Technical Field

[0001] This invention relates to the field of artificial intelligence sensor fabrication technology, specifically to a method for fabricating a highly crystalline cellulose piezoelectric film and its sensor, as well as its application. Background Technology

[0002] With the increasing prevalence of AI applications in wearable devices, intelligent robots, human-computer interaction, and health management, the market has placed more stringent demands on self-powered sensors, requiring them to simultaneously possess comprehensive performance characteristics such as self-powering, high resolution, and high flexibility. When flexible piezoelectric materials are used as sensing elements, their piezoelectric effect can efficiently convert the mechanical energy prevalent in the environment into electrical energy, satisfying both their own operational needs and storing and utilizing surplus energy. This perfectly aligns with the design requirements of high flexibility while achieving self-powered sensing.

[0003] Currently, although synthetically produced polyvinylidene fluoride (PVDF) and its copolymers (such as PVDF-TrFE and PVDF-HFP) are considered to be the best-performing flexible piezoelectric materials, their inherent limitations cannot be ignored: they are difficult to biodegrade, pose potential environmental risks due to their high fluorine content, and require complex polarization processes. Natural flexible piezoelectric materials can effectively avoid these problems, but natural cellulose exhibits a relatively low piezoelectric effect when used as a flexible piezoelectric material. Summary of the Invention

[0004] (a) Purpose of the invention The purpose of this invention is to provide a method for preparing a highly crystalline cellulose piezoelectric membrane and its sensor, as well as its application. Based on organic base-assisted ultrasonic vibration technology, the crystallinity of the cellulose piezoelectric membrane is improved, the piezoelectric effect of the cellulose piezoelectric membrane is activated, and the sensitivity of the sensor is further improved.

[0005] (II) Technical Solution To address the above problems, this invention provides a method for preparing a highly crystalline cellulose piezoelectric film, comprising: The raw materials for the cellulose piezoelectric membrane are pretreated to obtain the first material; The first material is placed in an organic alkali solution and subjected to ultrasound to obtain the second material; The second material is dried to obtain a cellulose piezoelectric film.

[0006] In another aspect of the present invention, preferably, the raw materials for the cellulose piezoelectric membrane include: ginseng fruit peel, cucumber peel, cantaloupe peel, pear peel, and loquat peel.

[0007] In another aspect of the present invention, preferably, the pretreatment of the raw materials for the cellulose piezoelectric film to obtain the first material includes: The raw material of the cellulose piezoelectric membrane is immersed in a first solution for a first time to obtain a pretreated material; The pretreated material is cleaned to obtain the first material.

[0008] In another aspect of the present invention, preferably, the first solution comprises a sodium bicarbonate solution or a citric acid solution, and the mass concentration of the first solution is 2-25 g / L; the mass ratio of the raw material of the cellulose piezoelectric membrane to the first solution is 1:3-1:40, and the first time is 10-30 min; The cleaning process includes cleaning with a first deionized water.

[0009] In another aspect of the present invention, preferably, the organic base solution comprises a second deionized water and an organic base; The organic bases include triethanolamine, diethanolamine, ethylamine, ammonia, methylamine, ethylamine, propylamine, and triethylamine; The mass ratio of the second deionized water to the organic base is 5:1 to 300:1; The mass ratio of the first material to the organic base is 0.15:1 to 100:1. In another aspect of the present invention, preferably, the frequency of the ultrasound is 20kHz to 40kHz, and the duration of the ultrasound is 1 to 8 hours.

[0010] In another aspect of the present invention, preferably, the drying temperature is 30~60°C and the drying time is 0.5~12h.

[0011] In another aspect, preferably, a method for manufacturing a sensor, the sensor comprising: First copper foil, first flexible substrate, cellulose piezoelectric film, second flexible substrate and second copper foil; The cellulose piezoelectric membrane is prepared using the preparation method described above; The method for preparing the sensor includes: The first flexible substrate includes a first connecting surface and a first conductive surface, the second flexible substrate includes a second connecting surface and a second conductive surface, and the cellulose piezoelectric film includes a first surface and a second surface; The first copper foil is connected to the first connecting surface, the first surface is connected to the first conductive surface, the second surface is connected to the second conductive surface, and the second connecting surface is connected to the second copper foil to obtain the device; A sensor is obtained by encapsulating the device on all four sides with insulating material.

[0012] In another aspect of the present invention, preferably, the first copper foil includes a first copper foil body and a first conductor, and the second copper foil includes a second copper foil body and a second conductor; The insulating material includes polyimide insulating tape.

[0013] In another aspect, preferably, the application of a cellulose piezoelectric film prepared by the preparation method described above or a sensor prepared by the preparation method described above in wearable electronic devices, intelligent robots, human-computer interaction, human health monitoring and simulated real-time alarm microsystems.

[0014] (III) Beneficial Effects The above-described technical solution of the present invention has the following beneficial technical effects: The cellulose piezoelectric membrane of this invention is prepared using renewable waste fruit and vegetable peels as raw materials and obtained through organic alkali-assisted ultrasonic vibration technology. Under the synergistic effect of mild organic alkali and ultrasound, localized glycosidic bond breakage and preferential hydrolysis occur in the hemicellulose and amorphous cellulose regions of the fruit and vegetable peels, achieving microstructural reorganization, significantly improving crystallinity, and making the stacking of slender crystalline fibers within the cellulose layers more orderly, while increasing the number of asymmetric dipoles. This achieves controllable crystalline region strengthening and structural optimization, greatly activating the piezoelectric effect of the cellulose piezoelectric membrane. The recyclable organic alkali and the renewable waste fruit and vegetable peels as raw materials both conform to environmental protection principles. Attached Figure Description

[0015] Figure 1 This is an overall flowchart of one embodiment of the present invention; Figure 2 This is a macroscopic photograph of the cellulose piezoelectric film of Embodiment 1 of the present invention; Figure 3 This is the XRD curve of the cellulose piezoelectric membrane of Embodiment 1 of the present invention; Figure 4 This is a cross-sectional SEM image of the cellulose piezoelectric membrane of Embodiment 1 of the present invention; Figure 5 This is an output voltage-time curve obtained by the sensor of Embodiment 1 of the present invention under different conditions; Figure 6 This is the output voltage-force curve of the sensor in Embodiment 1 of the present invention; Figure 7 This is the output voltage-time curve of the sensor in Embodiment 1 of the present invention measured under the action of sound emitted by the speaker; Figure 8 This is a graph showing the output voltage-time response of the sensor in Embodiment 1 of the present invention under different water flow conditions. Figure 9 This is the XRD pattern of the cellulose piezoelectric film in Comparative Example 1; Figure 10 This is the output voltage-force curve of the sensor in Comparative Example 1. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0017] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0018] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0019] Example A method for preparing a highly crystalline cellulose piezoelectric film. Figure 1 An overall flowchart of one embodiment of the present invention is shown, as follows: Figure 1 As shown, it includes: The raw materials for the cellulose piezoelectric membrane are pretreated to obtain a first material. The raw material for the cellulose piezoelectric membrane is biodegradable biomass fruit and vegetable peels. Residual fruit and vegetable pulp is removed from the biomass peels by mechanical scraping or manual peeling, leaving only a relatively intact outer layer to obtain a base membrane. In this embodiment, the raw materials for the cellulose piezoelectric membrane include: ginseng fruit peel, cucumber peel, cantaloupe peel, pear peel, and loquat peel. These materials are rich in natural cellulose and possess a certain natural membrane structure. The pretreatment includes: The raw materials of the cellulose piezoelectric membrane are immersed in a first solution for a first time to obtain a pretreated material. The first solution includes a sodium bicarbonate solution or a citric acid solution, which can selectively remove hemicellulose, pectin, some lignin and soluble impurities in the raw materials. The mass concentration of the first solution is 2~25 g / L, specifically 2 g / L, 5 g / L, 8 g / L, 10 g / L, 15 g / L, 20 g / L or 25 g / L, etc. The mass ratio of the raw materials of the cellulose piezoelectric membrane to the first solution is 1:3~1:40, specifically 1:3, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35 or 1:40, etc. The first time is 10~30 min, specifically 10 min, 15 min, 20 min, 25 min or 30 min, etc. The immersion process is carried out at room temperature, and stirring is used to improve the immersion uniformity.

[0020] The pretreated material is cleaned to obtain a first material. Cleaning includes washing with first deionized water. After soaking, the material is removed and rinsed multiple times with the first deionized water until no obvious foam residue remains in the washing solution, ensuring that the soaking solvent is fully removed. The number of cleaning cycles can be 3 to 5, with each cleaning session lasting 1 to 5 minutes.

[0021] Furthermore, the first material is dimensionally standardized by cutting it into quadrilaterals of 0.5~1cm×0.5~1cm or circles with a diameter of 0.5~1cm. Cutting the material into regular shapes ensures that the sample sizes are consistent, which is beneficial for the repeatability of subsequent performance tests.

[0022] The first material is placed in an organic alkali solution and subjected to ultrasound to obtain the second material; the organic alkali solution includes a second deionized water and an organic alkali; the organic alkali can regulate the intermolecular forces of cellulose, thereby achieving the control of the microstructure of cellulose.

[0023] The organic base includes triethanolamine, diethanolamine, ethylamine, ammonia, methylamine, ethylamine, propylamine, and triethylamine; the mass ratio of the second deionized water to the organic base is 5:1 to 300:1, specifically 5:1, 10:1, 20:1, 50:1, 100:1, 150:1, or 300:1, etc. When the proportion of organic base is higher, it is beneficial to enhance the degumming, removal of hemicellulose and lignin; when the proportion of deionized water is higher, it is beneficial to uniformly disperse the system and avoid excessive alkalinity from damaging the cellulose structure. The mass ratio of the first material to the organic base is 0.15:1 to 100:1, specifically 0.15:1, 1:1, 5:1, 10:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, or 100:1. Within this range, the organic base can ensure the full action of the material, while avoiding resource waste or side reactions due to excessive alkali dosage. For example, 1.8 to 20 g of the first material is placed in a 100 to 500 mL glass container, and 60 to 300 mL of [unspecified ingredient] is added to the glass container. Deionized water and 0.2-12g of organic alkali are used to float a glass container, along with the biomass fruit and vegetable peels, in an ultrasonic cleaner for ultrasonic treatment. The ultrasonic frequency is 20kHz-40kHz, specifically 20kHz, 25kHz, 30kHz, 35kHz, or 40kHz, and the ultrasonic treatment time is 1-8 hours, specifically 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, or 8 hours. Within this range, ultrasonic treatment, through cavitation and microjets, helps to disrupt the internal structure of the raw materials and improve the penetration ability of the organic alkali into cellulose. After ultrasonic treatment, the container can be repeatedly washed with deionized water until the washing solution is nearly neutral to remove residual organic alkali and soluble impurities. Obtained through organic base-assisted ultrasonic vibration technology, under the synergistic effect of mild organic base and ultrasound, local breakage and preferential hydrolysis of glycosidic bonds occur in the hemicellulose and amorphous cellulose regions of fruit and vegetable peels, achieving microstructure reorganization, significantly improving crystallinity, making the stacking of slender crystal fibers in cellulose layers more orderly, and increasing the number of asymmetric dipoles, achieving controllable crystalline region strengthening and structural optimization, and greatly activating the piezoelectric effect of cellulose piezoelectric film.

[0024] The second material is dried to obtain a cellulose piezoelectric film. The drying temperature is 30~60℃, specifically 30℃, 35℃, 40℃, 45℃, 50℃, 55℃ or 60℃, etc., and the drying time is 0.5h~12h, specifically 0.5h, 1h, 3h, 5h, 7h, 9h, 11h or 12h, etc.; the drying method can be natural drying, forced air drying or vacuum drying. During the drying process, the material can be laid flat on a polytetrafluoroethylene plate or glass substrate to ensure the flatness and thickness uniformity of the film.

[0025] This embodiment also provides a method for manufacturing a sensor, the sensor comprising: The sensor comprises a first copper foil, a first flexible substrate, a cellulose piezoelectric film, a second flexible substrate, and a second copper foil. The first copper foil includes a first copper foil body and a first wire, and the second copper foil includes a second copper foil body and a second wire. Specifically, the sensor has a layered structure, which, from bottom to top, includes a first copper foil, a first flexible substrate, a cellulose piezoelectric film, a second flexible substrate, and a second copper foil.

[0026] The cellulose piezoelectric film is prepared using the preparation method described above, and the sensor uses an interlayer connection method to achieve stable output of piezoelectric signals.

[0027] The method for preparing the sensor includes: The first flexible substrate includes a first connecting surface and a first conductive surface, and the second flexible substrate includes a second connecting surface and a second conductive surface. The flexible substrate can be prepared using flexible polymer materials such as polyethylene terephthalate, polyimide, or polydimethylsiloxane. The conductive surface can be formed by coating a conductive layer, such as silver paste, carbon paste, or vapor-deposited metal film, to ensure good charge collection capability. Furthermore, the thickness of the conductive layer is 1~50 μm to balance conductivity and flexibility. The cellulose piezoelectric film includes a first surface and a second surface. The first copper foil is connected to the first connecting surface, the first surface is connected to the first conductive surface, the second surface is connected to the second conductive surface, and the second connecting surface is connected to the second copper foil to obtain a device. The connection methods between the first copper foil and the first connecting surface, and between the second connecting surface and the second copper foil, can be thermoforming, adhesive bonding, or lamination. Conductive adhesive or thermoforming can be used to ensure a strong connection and low resistance. The bonding process between the first surface of the cellulose piezoelectric film and the first conductive surface of the first flexible substrate can be carried out under pressure (e.g., 0.1~1 MPa) and temperature (e.g., room temperature to 60°C) to improve interfacial bonding strength and reduce interfacial air gaps. After the connection is completed, the cellulose piezoelectric film is located between the two conductive surfaces, forming a sandwich structure. Before encapsulation, copper wires are led out from the copper foil and encapsulated on all four sides of the device using insulating material to obtain the sensor. The insulating material includes polyimide insulating tape. After encapsulation, the device can be pressurized to enhance the stability of the interlayer bonding.

[0028] The sensor in this embodiment employs a simple stacked structure of cellulose piezoelectric film and utilizes highly conductive copper foil for auxiliary encapsulation. This optimizes the collection path of free charges, enhances the structural stability of the sensor under multi-dimensional stress, and effectively reduces charge dissipation by accelerating charge migration and extraction. While maintaining the sensor's simplicity, it significantly improves detection sensitivity and operational stability. This sensor combines high sensitivity, high flexibility, and self-powered characteristics. Its raw material is based on renewable waste fruit and vegetable peels, possessing completely environmentally friendly cellulose properties, highly consistent with the concept of green manufacturing. Not only can it serve as a self-powered micro-power source, but also, thanks to the excellent biocompatibility and functional modification potential of the cellulose piezoelectric film, it can be further expanded for the sensitive detection of environmental pollutants, achieving multi-functional integration from intelligent sensing to environmental monitoring. Simultaneously, the manufacturing process is green and environmentally friendly, the raw materials are inexpensive and renewable, and the organic alkali additives are easily recyclable and reusable, embodying the concepts of circular economy and green environmental protection.

[0029] This embodiment also provides an application of the cellulose piezoelectric film prepared by the preparation method described above or the sensor prepared by the preparation method described above in wearable electronic devices, intelligent robots, human-computer interaction, human health monitoring and simulated real-time alarm microsystems.

[0030] Example 1 The preparation of cellulose piezoelectric films includes: Remove any remaining pulp from the ginseng fruit peel; then soak the ginseng fruit peel in a sodium bicarbonate solution with a mass concentration of 15 g / L for 15 minutes, with a mass ratio of ginseng fruit peel to sodium bicarbonate solution of 1:20, and then rinse with deionized water; finally, cut it into 1 cm × 1 cm quadrilaterals.

[0031] The mass ratio of the second deionized water to the organic alkali is 20:1, and the mass ratio of the first material to the organic alkali is 2:1. 10g of ginseng peel is placed in a 300mL glass container, and 100mL of the second deionized water is added. 5g of the organic alkali triethanolamine is added. The glass container, along with the biomass fruit and vegetable peel, is floated in an ultrasonic cleaner for ultrasonication at a frequency of 30kHz for 2 hours. Finally, the ginseng peel is removed from the glass container and dried at 60℃ for 4 hours to obtain a cellulose piezoelectric membrane. Figure 2 This is a macroscopic photograph of the cellulose piezoelectric film of Embodiment 1 of the present invention, as shown below. Figure 2 As shown, the cellulose piezoelectric film prepared in Example 1 has high flatness and integrity. Figure 3 The XRD pattern of the cellulose piezoelectric film of Embodiment 1 of the present invention is shown; as follows: Figure 3As shown, the diffraction peak appearing at a 2θ angle of approximately 21.14° corresponds to the (002) crystal plane of cellulose, and the crystallinity obtained is 39.19%, indicating that the cellulose piezoelectric film of Example 1 contains a large number of ordered cellulose microcrystal regions. Figure 4 A cross-sectional SEM image of the cellulose piezoelectric membrane of Embodiment 1 of the present invention is shown, as follows. Figure 4 As shown, the cellulose piezoelectric film prepared in Example 1 is composed of a large number of stacked cellulose nanosheets, which are arranged in a highly ordered manner.

[0032] The fabrication of the sensor includes: The first flexible substrate includes a first connecting surface and a first conductive surface, the second flexible substrate includes a second connecting surface and a second conductive surface, and the cellulose piezoelectric film includes a first surface and a second surface; The first copper foil is connected to the first connecting surface of the first flexible substrate, the first surface of the cellulose piezoelectric film is connected to the first conductive surface of the first flexible substrate, the second surface of the cellulose piezoelectric film is connected to the second conductive surface of the second flexible substrate, and the second connecting surface of the second flexible substrate is connected to the second copper foil to obtain a device; an insulating material is used to encapsulate the device on all four sides to obtain a sensor. Figure 5 The following diagram shows the output voltage-time curves obtained by the sensor of Embodiment 1 of the present invention under different conditions, as shown in the figure. Figure 5 As shown, the sensor in Embodiment 1 can output a stable voltage according to the magnitude of the applied force without any external power supply, thus possessing self-powering characteristics. Figure 6 The output voltage-force curve of the sensor in Embodiment 1 of the present invention is shown, as follows: Figure 6 As shown, the output voltage of the sensor in Example 1 is directly proportional to the applied force and has high sensitivity, with a corresponding sensitivity of 24.83 mV / N. Figure 7 The following is a diagram showing the output voltage-time curve of the sensor according to Embodiment 1 of the present invention under the influence of sound emitted by an audio source. Figure 7 As shown, the sensor of Example 1 is able to sensitively detect minute changes caused by sound pressure. Figure 8 The following diagram shows the output voltage-time response curves of the sensor in Embodiment 1 of the present invention measured under different water flow conditions, as shown in the figure. Figure 8 As shown, the sensor in Example 1 can sensitively identify the electrical signal output caused by changes in water pressure. When the water flow fluctuates abnormally, the sensor output voltage shows obvious response characteristics, verifying the sensor's ability to quickly sense changes in fluid pressure.

[0033] Example 2 The preparation of cellulose piezoelectric films includes: Remove any remaining pulp from the cucumber peel; then soak the cucumber peel in a citric acid solution with a mass concentration of 2 g / L for 10 minutes, with a mass ratio of cucumber peel to citric acid solution of 1:3, and then rinse with deionized water; finally, cut it into 1 cm × 0.5 cm quadrilaterals.

[0034] The mass ratio of the second deionized water to the organic base is 5:1, and the mass ratio of the first material to the organic base is 0.15:1. 3.6g of cucumber peel is placed in a 300mL glass container, and 120mL of the second deionized water is added. 24g of the organic base ethylamine is added. The glass container, along with the biomass fruit and vegetable peel, is floated in an ultrasonic cleaner for ultrasonication at a frequency of 20kHz for 8 hours. Finally, the cucumber peel is removed from the glass container and dried at 50℃ for 0.5 hours to obtain a cellulose piezoelectric membrane.

[0035] The fabrication of the sensor includes: The first flexible substrate includes a first connecting surface and a first conductive surface, the second flexible substrate includes a second connecting surface and a second conductive surface, and the cellulose piezoelectric film includes a first surface and a second surface; The first copper foil is connected to the first connecting surface of the first flexible substrate, the first surface of the cellulose piezoelectric film is connected to the first conductive surface of the first flexible substrate, the second surface of the cellulose piezoelectric film is connected to the second conductive surface of the second flexible substrate, and the second connecting surface of the second flexible substrate is connected to the second copper foil to obtain a device; an insulating material is used to encapsulate the device on all four sides to obtain a sensor.

[0036] Example 3 The preparation of cellulose piezoelectric films includes: Remove any remaining pulp from the loquat peel; then soak the loquat peel in a citric acid solution with a concentration of 25 g / L for 30 minutes, with a mass ratio of loquat peel to citric acid solution of 1:40, and then rinse with deionized water; finally, cut it into 1 cm circles.

[0037] The mass ratio of the second deionized water to the organic alkali is 300:1, and the mass ratio of the first material to the organic alkali is 100:1. 100g of loquat peel is placed in a 500mL glass container, and 300mL of the second deionized water is added. 1g of organic alkali ammonia is added. The glass container, along with the biomass fruit and vegetable peel, is floated in an ultrasonic cleaner for ultrasonication at a frequency of 40kHz for 1 hour. Finally, the cucumber peel is removed from the glass container and dried at 30℃ for 12 hours to obtain a cellulose piezoelectric membrane.

[0038] The fabrication of the sensor includes: The first flexible substrate includes a first connecting surface and a first conductive surface, the second flexible substrate includes a second connecting surface and a second conductive surface, and the cellulose piezoelectric film includes a first surface and a second surface; The first copper foil is connected to the first connecting surface of the first flexible substrate, the first surface of the cellulose piezoelectric film is connected to the first conductive surface of the first flexible substrate, the second surface of the cellulose piezoelectric film is connected to the second conductive surface of the second flexible substrate, and the second connecting surface of the second flexible substrate is connected to the second copper foil to obtain a device; an insulating material is used to encapsulate the device on all four sides to obtain a sensor.

[0039] Comparative Example 1 The cellulose piezoelectric membrane was not treated with ultrasound or organic alkali, but otherwise it was the same as in Example 1. Figure 9 The XRD pattern of the cellulose piezoelectric film in Comparative Example 1 is shown, as follows. Figure 9 As shown, in Comparative Example 1, the peak on the (002) crystal plane appears at a 2θ angle of 21.52°, with a corresponding crystallinity (CrI) of 30.33%. Figure 10 The output voltage-force curve of the sensor in Comparative Example 1 is shown, as follows: Figure 10 As shown, the sensor's sensitivity is 134 mV / N.

[0040] Table 1 shows the experimental results of the sensors of Examples 1-3 and Comparative Example 1. As shown in Table 1, the crystallinity of Examples 1-3 is better than that of Comparative Example 1, and the sensitivity of the sensors of Examples 1-3 is better than that of Comparative Example 1. This indicates that the preparation method of this embodiment can improve the crystallinity of the cellulose piezoelectric film, activate the piezoelectric effect of the cellulose piezoelectric film, and improve the sensitivity of the sensor.

[0041] Table 1. Experimental results of the sensors in Examples 1-3 and Comparative Example 1 It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

[0042] The present invention has been described above with reference to embodiments thereof. However, these embodiments are merely illustrative and not intended to limit the scope of the invention. The scope of the invention is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the invention, and all such substitutions and modifications should fall within the scope of the invention.

[0043] Although embodiments of the present invention have been described in detail, it should be understood that various changes, substitutions, and modifications can be made to the embodiments of the present invention without departing from the spirit and scope of the invention.

[0044] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a highly crystalline cellulose piezoelectric film, characterized in that, include: The raw materials for the cellulose piezoelectric membrane are pretreated to obtain the first material; The first material is placed in an organic alkali solution and subjected to ultrasound to obtain the second material; The second material is dried to obtain a cellulose piezoelectric film.

2. The method for preparing a highly crystalline cellulose piezoelectric membrane according to claim 1, characterized in that, The raw materials for the cellulose piezoelectric membrane include: ginseng fruit peel, cucumber peel, cantaloupe peel, pear peel, and loquat peel.

3. The method for preparing a highly crystalline cellulose piezoelectric membrane according to claim 1, characterized in that, The pretreatment of the raw materials for the cellulose piezoelectric film to obtain the first material includes: The raw material of the cellulose piezoelectric membrane is immersed in a first solution for a first time to obtain a pretreated material; The pretreated material is cleaned to obtain the first material.

4. The method for preparing a highly crystalline cellulose piezoelectric membrane according to claim 3, characterized in that, The first solution includes a sodium bicarbonate solution or a citric acid solution, and the mass concentration of the first solution is 2~25 g / L; the mass ratio of the raw material of the cellulose piezoelectric membrane to the first solution is 1:3~1:40, and the first time is 10~30 min; The cleaning process includes cleaning with a first deionized water.

5. The method for preparing a highly crystalline cellulose piezoelectric film according to claim 1, characterized in that, The organic base solution comprises a second deionized water and an organic base; The organic bases include triethanolamine, diethanolamine, ethylamine, ammonia, methylamine, ethylamine, propylamine, and triethylamine; The mass ratio of the second deionized water to the organic base is 5:1 to 300:1; The mass ratio of the first material to the organic base is 0.15:1 to 100:

1.

6. The method for preparing a highly crystalline cellulose piezoelectric membrane according to claim 1, characterized in that, The frequency of the ultrasound is 20kHz to 40kHz, and the duration of the ultrasound is 1 to 8 hours.

7. The method for preparing a highly crystalline cellulose piezoelectric film according to claim 1, characterized in that, The drying temperature is 30~60℃, and the drying time is 0.5~12h.

8. A method for manufacturing a sensor, characterized in that, The sensor includes: First copper foil, first flexible substrate, cellulose piezoelectric film, second flexible substrate and second copper foil; The cellulose piezoelectric membrane is prepared using the preparation method according to any one of claims 1-7; The method for preparing the sensor includes: The first flexible substrate includes a first connecting surface and a first conductive surface, the second flexible substrate includes a second connecting surface and a second conductive surface, and the cellulose piezoelectric film includes a first surface and a second surface; The first copper foil is connected to the first connecting surface, the first surface is connected to the first conductive surface, the second surface is connected to the second conductive surface, and the second connecting surface is connected to the second copper foil to obtain the device; A sensor is obtained by encapsulating the device on all four sides with insulating material.

9. The preparation method according to claim 8, characterized in that, The first copper foil includes a first copper foil body and a first conductor, and the second copper foil includes a second copper foil body and a second conductor; The insulating material includes polyimide insulating tape.

10. The application of a cellulose piezoelectric film prepared by any one of claims 1-7 or a sensor prepared by the method described in claim 8 or 9 in wearable electronic devices, intelligent robots, human-computer interaction, human health monitoring and simulated real-time alarm microsystems.

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