A high-friction voltage hydroxyethyl cellulose sensing material and a preparation method thereof

Abstract

The application relates to the fields of nanometer friction power generation sensing technology and film material manufacturing, and particularly relates to a high-friction-voltage hydroxyethyl cellulose sensing material and a preparation method thereof. The sensing material comprises a three-layer structure, and from top to bottom, the three-layer structure comprises an upper hydroxyethyl cellulose film, a polyvinylidene fluoride film and a lower hydroxyethyl cellulose film. The HEC film with aramid nanofibers introduced in the outer layer is used as a friction layer and a mechanical support layer, and the middle PVDF film is used as a static electricity reservation phase, so that the organic combination of static electricity coupling and charge storage is realized. The application not only provides a new idea for the development of the friction nanometer power generation technology, but also provides a more efficient and environment-friendly solution for the application in the fields of wearable devices, self-powered sensors and the like.

Description

Technical Field

[0001] This invention relates to the fields of nano-triboelectric sensing technology and membrane material manufacturing, specifically to a high triboelectric voltage hydroxyethyl cellulose sensing material and its preparation method. Background Technology

[0002] With the surging demand for sustainable energy and efficient sensors from technology, triboelectric nanogenerators (TENGs), as a novel energy conversion technology, have shown great application potential by utilizing the triboelectric charge effect generated when two different materials come into contact, separate, or slide to collect mechanical energy and convert it into electrical energy. Compared with traditional energy conversion methods, TENGs offer advantages such as high voltage and low current, simple structure, low cost, environmental friendliness, and the ability to convert minute mechanical energy from everyday life into electrical energy, providing new energy solutions for fields such as the Internet of Things, wearable devices, and environmental monitoring.

[0003] However, the limitations of traditional materials in terms of mechanical strength, frictional properties, and charge retention restrict their application potential. For example, under high-intensity or frequent mechanical stress, many traditional materials are prone to fatigue fracture or deformation, leading to decreased power generation efficiency or even equipment damage. An ideal TENG material should have a high coefficient of friction to generate more charge, while also possessing good wear resistance to extend its service life.

[0004] Hydroxyethyl cellulose (HEC) is a potential material for high-performance triboelectric (TENG) films due to its excellent biocompatibility, processability, and film-forming properties, which can improve triboelectric properties and durability. Polyvinylidene fluoride (PVDF), as a charge-retaining phase, has a high dielectric constant and significant piezoelectric effect, enhancing the charge storage and electrical output performance of TENGs. At the same time, its insulation properties reduce charge leakage and improve conversion efficiency.

[0005] This invention innovatively integrates the advantages of HEC and PVDF to design a three-layer sensing material structure: an HEC film as the top and bottom layers, and a PVDF film as the middle layer, forming a three-dimensional intercalation structure. This design not only leverages the triboelectric properties of HEC and the high dielectric properties of PVDF, but also enhances mechanical and electrical properties through multilayer composites, opening up new avenues for the fabrication of high-performance TENG devices. Summary of the Invention

[0006] To address the shortcomings of traditional materials in terms of mechanical strength, friction performance, and charge retention, this invention provides a method for preparing high triboelectric voltage hydroxyethyl cellulose sensing materials.

[0007] This invention is achieved through the following technical solution:

[0008] A high triboelectric voltage hydroxyethyl cellulose sensing material comprises a three-layer structure, consisting of an upper hydroxyethyl cellulose film, a polyvinylidene fluoride film, and a lower hydroxyethyl cellulose film, from top to bottom.

[0009] A method for preparing a high triboelectric voltage hydroxyethyl cellulose sensing material includes the following steps:

[0010] Step 1: Prepare a mixed dispersion of hydroxyethyl cellulose and aramid nanofibers and a spinning solution containing polyvinylidene fluoride;

[0011] Step 2: The hydroxyethyl cellulose and aramid nanofiber mixed dispersion is used to obtain the lower hydroxyethyl cellulose film by a combination of casting and drying.

[0012] Polyvinylidene fluoride (PVDF) films are obtained by electrospinning a spinning solution containing PVDF.

[0013] Step 3: Place the polyvinylidene fluoride film on the upper surface of the dried lower hydroxyethyl cellulose film; then, on the upper surface of the polyvinylidene fluoride film, prepare a wet upper hydroxyethyl cellulose film by casting a mixed dispersion of hydroxyethyl cellulose and aramid nanofibers; after drying, obtain a three-dimensional intercalated HEC-PVDF-HEC high triboelectric voltage sensing material.

[0014] Preferably, in step 1, the preparation method of the mixed dispersion of hydroxyethyl cellulose and aramid nanofibers is as follows: at 45-55℃, 2-3g of hydroxyethyl cellulose powder is dissolved in 200-300mL of aramid nanofiber dispersion for 20-30min to obtain the mixed dispersion of hydroxyethyl cellulose and aramid nanofibers; wherein, the viscosity of hydroxyethyl cellulose is 2600-3300mpa.s, and the concentration of hydroxyethyl cellulose dispersion is 0.010-0.015g / mL.

[0015] Preferably, the preparation of the aramid nanofiber mixed dispersion is as follows: First, an alkaline solution, para-aramid fibers, and dimethyl sulfoxide are stirred and mixed to obtain dispersion A; wherein, the mass ratio of para-aramid fibers to dimethyl sulfoxide is 2-3:200-300, the solute in the alkaline solution is potassium hydroxide, the concentration of the solute in the alkaline solution is 0.3-0.6 g / mL, and the ratio of alkaline solution to para-aramid fibers is 1-2 mL:2-3 g;

[0016] Dispersion A was uniformly dispersed in deionized water, and then allowed to stand and filtered to obtain para-aramid nanofiber dispersion B; wherein the volume ratio of water to dispersion A was 1000-1500:50-100, and the concentration of para-aramid nanofiber dispersion was 1%-1.5%.

[0017] Preferably, in step 1, the spinning solution containing polyvinylidene fluoride is prepared as follows: the spinning solution is obtained by dissolving polyvinylidene fluoride in N,N-dimethylformamide solution.

[0018] Preferably, the ratio of polyvinylidene fluoride to N,N-dimethylformamide solution is 4-5 g: 7-9 mL, the dissolution temperature is 60-70℃, the rotation speed is 100-200 r / min, and the time is 2-3 h.

[0019] Preferably, in step 2, during the preparation of the lower hydroxyethyl cellulose film, the drying temperature is 60-70°C and the drying time is 10-12 hours, and the film thickness of the lower hydroxyethyl cellulose film after drying is 0.06-0.08 mm.

[0020] Preferably, in step 2, during the electrospinning process, the voltage is 15-17kV, the temperature is 35-45℃, the humidity is 65%-75%, the spinning solution spraying rate is 0.008-0.010mL / min, and the time is 6-8h.

[0021] Preferably, in step 3, the drying process is carried out at a temperature of 60-70°C for 10-12 hours, and the film thickness of the upper hydroxyethyl cellulose film after drying is 0.06-0.08 mm.

[0022] A grid-structured triboelectric nanogenerator prepared from the aforementioned high triboelectric voltage hydroxyethyl cellulose sensing material.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] First, this invention discloses a high triboelectric voltage hydroxyethyl cellulose (HEC) sensing material prepared using a phase-oriented assembly strategy. A carefully designed three-dimensional intercalation (HEC-PVDF-HEC) introduces a wide-bandgap charge-retaining polyvinylidene fluoride (PVDF) electrospun film into the triboelectric phase hydroxyethyl cellulose (HEC) film. This three-dimensional intercalation (HEC-PVDF-HEC) structure, with two HEC layers sandwiching a PVDF film, achieves an organic combination of electrostatic coupling and charge storage. The HEC layer provides excellent electrostatic coupling induction and triboelectric generation capabilities, while the PVDF layer acts as the charge-retaining phase, effectively improving charge accumulation and transport efficiency. This structural design not only enhances the material's structural stability but also optimizes the charge transport and retention paths, significantly improving the efficiency and stability of nano-triboelectric generation, and further enhancing the output stability and sensitivity of the nano-triboelectric generator.

[0025] Secondly, after long-term experiments, this invention has selected hydroxyethyl cellulose (HEC) as the contact friction layer. Its advantages are: (1) good solubility and non-ionicity: HEC can be dissolved and dispersed in aqueous solvents, and it is low in cost and widely available, making it easy to scale up processing and application; (2) Hydroxyethyl cellulose (HEC) is composed of a cellulose main chain and a hydroxyethyl side chain structure. It is a water-soluble polymer compound prepared by etherification reaction of cellulose with ethylene oxide (or chloroethanol). The surface is rich in hydroxyl groups, which help to attract charge transfer in electrostatic coupling induction, and has the inherent advantage of preparing high triboelectric voltage positive electrode materials; (3) HEC has good biocompatibility and degradability. It is degradable, renewable, and environmentally friendly, which makes HEC-based nano-triboelectric power generation sensing materials have potential application advantages in the biomedical field, such as wearable medical devices.

[0026] Next, polyvinylidene fluoride (PVDF) was used to prepare the cathode material for nano-triboelectric power generation sensors. Its advantages in charge retention phase are: (1) PVDF's unique molecular structure and dipole arrangement enable it to generate stronger electrical signals when subjected to external forces, more effectively converting mechanical energy into electrical energy, and generating and retaining more charge during friction; (2) The fluorine atoms in the PVDF molecular chain have strong electronegativity, and the CF bonds formed with carbon atoms have high stability and polarity. This polarity allows PVDF molecules to generate dipoles when subjected to external forces, forming a stable electric field within the material, which helps in charge accumulation and stabilization; (3) PVDF can resist the erosion of various environmental factors (such as humidity, temperature, acid and alkali), enabling PVDF-based cathode materials to maintain stable charge retention performance even under harsh environments, extending the service life of nano-triboelectric power generation sensors.

[0027] Furthermore, the introduction of aramid nanofibers to prepare cathode materials for nano-triboelectric sensing has the following advantages: (1) Excellent mechanical properties: Aramid nanofibers have a linear rigid extended chain configuration due to the macromolecular chains composed of benzene rings and amide groups. They are not easily deformed when the fibers are subjected to stress, and have the characteristics of high strength and high modulus. When combined with HEC to form a composite film, stress transfer can improve the overall mechanical and triboelectric properties of the material; (2) Aramid nanofibers have the characteristics of high temperature resistance and corrosion resistance, and maintain stable triboelectric performance in a wide temperature range and harsh chemical environment; (3) Aramid nanofibers can form good interfacial bonding with a variety of matrix materials, which helps to reduce the leakage and loss of charge at the interface and improve the triboelectric and charge retention performance of the cathode material.

[0028] Furthermore, the present invention provides a method for preparing a high triboelectric voltage hydroxyethyl cellulose (HEC) sensing material by introducing aramid nanofibers into the HEC matrix through dissolution blending, which significantly improves the strength and toughness of the composite material. Simultaneously, the addition of nanofibers increases the specific surface area of ​​the material, which is beneficial for the generation and transfer of triboelectric charges, further improving the output performance of the triboelectric nanogenerator.

[0029] Furthermore, this invention employs a casting method to prepare HEC films, with precise control over drying temperature and time, offering advantages in scalability. Simultaneously, in preparing PVDF films, this invention utilizes electrospinning technology, optimizing parameters such as spinning solution ratio, spinning voltage, and roller rotation speed. The resulting PVDF films exhibit wide bandgap and high specific surface area, providing a strong guarantee for the preparation of high-performance nano-triboelectric sensing cathode materials. Attached Figure Description

[0030] Figure 1 This is a structural diagram of a high triboelectric voltage hydroxyethyl cellulose sensing material according to the present invention;

[0031] Figure 2 This is a flowchart of a method for preparing a high triboelectric voltage hydroxyethyl cellulose sensing material according to the present invention;

[0032] Figure 3 The triboelectric voltage is the triboelectric voltage of the high triboelectric voltage hydroxyethyl cellulose sensing material prepared in Example 1 of this invention.

[0033] Figure 4 The triboelectric voltage is the triboelectric voltage of the high triboelectric voltage hydroxyethyl cellulose sensing material prepared in Example 2 of this invention.

[0034] Figure 5 The triboelectric voltage is the triboelectric voltage of the high triboelectric voltage hydroxyethyl cellulose sensing material prepared in Example 3 of the present invention.

[0035] Figure 6 The triboelectric voltage of the high triboelectric voltage hydroxyethyl cellulose sensing material prepared in Example 4 of this invention is shown.

[0036] Figure 7 The triboelectric voltage is the triboelectric voltage of the high triboelectric voltage hydroxyethyl cellulose sensing material prepared in Example 5 of this invention. Detailed Implementation

[0037] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0038] This invention discloses a high triboelectric voltage hydroxyethyl cellulose sensing material, comprising a three-layer structure, from top to bottom being an upper hydroxyethyl cellulose film, a polyvinylidene fluoride film, and a lower hydroxyethyl cellulose film.

[0039] This invention also discloses a method for preparing a high triboelectric voltage hydroxyethyl cellulose sensing material, referring to... Figure 2 This includes the following steps:

[0040] Step 1: Prepare a mixed dispersion of hydroxyethyl cellulose and aramid nanofibers and a spinning solution containing polyvinylidene fluoride.

[0041] The preparation of the aramid nanofiber mixed dispersion is as follows: First, an alkaline solution, para-aramid fibers, and dimethyl sulfoxide are stirred and mixed to obtain dispersion A; wherein, the mass ratio of para-aramid fibers to dimethyl sulfoxide is 2-3:200-300, the solute in the alkaline solution is potassium hydroxide, the concentration of the solute in the alkaline solution is 0.3-0.6 g / mL, and the ratio of alkaline solution to para-aramid fibers is 1-2 mL:2-3 g;

[0042] Dispersion A was uniformly dispersed in deionized water, and then allowed to stand and filtered to obtain para-aramid nanofiber dispersion B; wherein the volume ratio of water to dispersion A was 1000-1500:50-100, and the concentration of para-aramid nanofiber dispersion was 1%-1.5%.

[0043] The preparation method of the mixed dispersion of hydroxyethyl cellulose and aramid nanofibers is as follows: at 45-55℃, 2-3g of hydroxyethyl cellulose powder is dissolved in 200-300mL of aramid nanofiber dispersion for 20-30min to obtain the mixed dispersion of hydroxyethyl cellulose and aramid nanofibers; wherein, the viscosity of hydroxyethyl cellulose is 2600-3300mpa.s, and the concentration of hydroxyethyl cellulose dispersion is 0.010-0.015g / mL.

[0044] The spinning solution containing polyvinylidene fluoride (PVDF) is prepared as follows: PVDF is dissolved in an N,N-dimethylformamide solution to obtain the spinning solution. The ratio of PVDF to N,N-dimethylformamide solution is 4–5 g: 7–9 mL, the dissolution temperature is 60–70 °C, the spinning speed is 100–200 r / min, and the dissolution time is 2–3 h.

[0045] Step 2: The hydroxyethyl cellulose and aramid nanofiber mixed dispersion is used to obtain the lower hydroxyethyl cellulose film by casting and drying; wherein the drying temperature is 60-70℃, the time is 10-12h, and the film thickness is 0.06-0.08mm.

[0046] Polyvinylidene fluoride (PVDF) films are obtained by electrospinning a spinning solution containing PVDF. During the electrospinning process, the voltage is 15–17 kV, the temperature is 35–45 °C, the humidity is 65%–75%, the spinning solution spin rate is 0.008–0.010 mL / min, and the time is 6–8 h.

[0047] Step 3: Place the polyvinylidene fluoride (PVDF) film on the upper surface of the dried lower hydroxyethyl cellulose (HFC) film; the two should adhere at this point. Then, on the upper surface of the PVDF film, prepare a wet upper hydroxyethyl cellulose (HFC) film using a casting method with a mixed dispersion of HFC and aramid nanofibers. After drying at 60–70°C for 10–12 hours, the dried upper HFC film, PVDF film, and lower HFC film will automatically bond together, thus obtaining a three-dimensional intercalated HEC-PVDF-HEC high triboelectric voltage sensing material. The upper and lower HFC films have the same thickness. Before drying, the thickness of the HFC and aramid nanofiber mixed dispersion poured into the mold is 8–10 mm. After drying, the film thickness of both is 0.06–0.08 mm.

[0048] Example 1

[0049] Step 1: Dissolve 2g of hydroxyethyl cellulose powder in 200mL of aramid nanofiber dispersion, and dissolve at 55℃ for 25min to obtain a mixed dispersion of hydroxyethyl cellulose and aramid nanofiber with a concentration of 0.01g / mL.

[0050] At 70℃, 4g of polyvinylidene fluoride was dissolved in 9mL of N,N-dimethylformamide solution and stirred at 200r / min for 3h to prepare the spinning solution for electrospinning membrane.

[0051] Step 2: The dispersion is uniformly poured into a polytetrafluoroethylene mold and dried in a hot oven at 60°C for 12 hours to obtain the lower hydroxyethyl cellulose film;

[0052] Polyvinylidene fluoride (PVDF) films were obtained by electrospinning the spinning solution of the electrospinning membrane. The voltage was 15.5 kV, the temperature was 35°C, the humidity was 65%, the spinning solution spraying rate was 0.008 mL / min, and the spinning time was 6 h.

[0053] Step 3: Adhere a polyvinylidene fluoride film to the lower hydroxyethyl cellulose film, and continue to cast a 10 mm thick mixed dispersion of hydroxyethyl cellulose and aramid nanofibers to obtain a wet upper hydroxyethyl cellulose film. Dry it in a hot oven at 60°C for 12 hours, and finally obtain the three-dimensional intercalated HEC-PVDF-HEC high triboelectric voltage sensing material.

[0054] Example 2

[0055] Step 1: Dissolve 2.5g of hydroxyethyl cellulose powder in 200mL of aramid nanofiber dispersion, and dissolve at 55℃ for 30min to obtain a mixed dispersion of hydroxyethyl cellulose and aramid nanofiber with a concentration of 0.0125g / mL.

[0056] At 70℃, 4g of polyvinylidene fluoride was dissolved in 9mL of N,N-dimethylformamide solution and stirred at 200r / min for 3h to prepare the spinning solution for electrospinning membrane.

[0057] Step 2: The dispersion is uniformly poured into a polytetrafluoroethylene mold and dried in a hot oven at 60°C for 12 hours to obtain the lower hydroxyethyl cellulose film;

[0058] Polyvinylidene fluoride (PVDF) film was obtained by electrospinning the spinning solution of the electrospinning membrane. The voltage was 15.5 kV, the temperature was 35 °C, the humidity was 65%, the spinning solution spraying rate was 0.010 mL / min, and the spinning time was 6 h.

[0059] Step 3: Adhere a polyvinylidene fluoride film to the lower hydroxyethyl cellulose film, and continue to cast a 10 mm thick mixture of hydroxyethyl cellulose and aramid nanofibers to obtain a wet upper hydroxyethyl cellulose film. Then, dry it in a hot oven at 60°C for 12 hours to finally obtain the three-dimensional intercalated HEC-PVDF-HEC high triboelectric voltage sensing material.

[0060] Example 3

[0061] Step 1: Dissolve 3g of hydroxyethyl cellulose powder in 200mL of aramid nanofiber dispersion, and dissolve at 55℃ for 30min to obtain a mixed dispersion of hydroxyethyl cellulose and aramid nanofiber with a concentration of 0.015g / mL.

[0062] At 70℃, 4.0 g of polyvinylidene fluoride was dissolved in 9 mL of N,N-dimethylformamide solution and stirred at 200 r / min for 3 h to prepare the spinning solution for electrospinning membrane.

[0063] Step 2: The dispersion is uniformly poured into a polytetrafluoroethylene mold and dried in a hot oven at 60°C for 12 hours to obtain the lower hydroxyethyl cellulose film;

[0064] Polyvinylidene fluoride (PVDF) films were obtained by electrospinning the spinning solution of the electrospinning membrane under the following conditions: voltage 15.5 kV, temperature 35 °C, humidity 65%, spinning solution spin rate 0.010 mL / min, and spinning time 6 h.

[0065] Step 3: Adhere a polyvinylidene fluoride film to the lower hydroxyethyl cellulose film, and continue to pour a 10 mm thick mixed dispersion of hydroxyethyl cellulose and aramid nanofibers to obtain a wet upper hydroxyethyl cellulose film. Dry it in a hot oven at 60°C for 12 h, and finally dry it to obtain a three-dimensional intercalated HEC-PVDF-HEC high triboelectric voltage sensing material.

[0066] Example 4

[0067] Step 1: Dissolve 3g of hydroxyethyl cellulose powder in 200mL of aramid nanofiber dispersion, and dissolve at 55℃ for 30min to obtain a mixed dispersion of hydroxyethyl cellulose and aramid nanofiber with a concentration of 0.015g / mL.

[0068] At 70℃, 4.5g of polyvinylidene fluoride was dissolved in 9mL of N,N-dimethylformamide solution and stirred at 200r / min for 3h to prepare the spinning solution for electrospinning membrane.

[0069] Step 2: The dispersion is uniformly poured into a polytetrafluoroethylene mold and dried in a hot oven at 60°C for 12 hours to obtain the lower hydroxyethyl cellulose film;

[0070] Polyvinylidene fluoride (PVDF) films were obtained by electrospinning the spinning solution of the electrospinning membrane under the following conditions: voltage 16 kV, temperature 40 °C, humidity 70%, spinning solution extrusion rate 0.010 mL / min, and spinning time 6.5 h.

[0071] Step 3: Adhere a polyvinylidene fluoride film to the lower hydroxyethyl cellulose film, and continue to pour a 10 mm thick mixed dispersion of hydroxyethyl cellulose and aramid nanofibers to obtain a wet upper hydroxyethyl cellulose film. Dry it in a hot oven at 60°C for 12 h, and finally dry it to obtain a three-dimensional intercalated HEC-PVDF-HEC high triboelectric voltage sensing material.

[0072] Example 5

[0073] Step 1: Dissolve 3g of hydroxyethyl cellulose powder in 200mL of aramid nanofiber dispersion, and dissolve at 55℃ for 30min to obtain a mixed dispersion of hydroxyethyl cellulose and aramid nanofiber with a concentration of 0.015g / mL.

[0074] At 70℃, 5g of polyvinylidene fluoride was dissolved in 9mL of N,N-dimethylformamide solution and stirred at 200r / min for 3h to prepare the spinning solution for electrospinning membrane.

[0075] Step 2: The dispersion is uniformly poured into a polytetrafluoroethylene mold and dried in a hot oven at 60°C for 12 hours to obtain the lower hydroxyethyl cellulose film;

[0076] Polyvinylidene fluoride (PVDF) films were obtained by electrospinning the spinning solution of the electrospinning membrane under the following conditions: voltage 17 kV, temperature 45 ℃, humidity 65%, spinning solution extrusion rate 0.010 mL / min, and spinning time 7 h.

[0077] Step 3: Adhere a polyvinylidene fluoride film to the lower hydroxyethyl cellulose film, and continue to cast a 10 mm thick mixed dispersion of hydroxyethyl cellulose and aramid nanofibers to obtain a wet upper hydroxyethyl cellulose film. Dry it in a hot oven at 60°C for 12 hours, and finally obtain the three-dimensional intercalated HEC-PVDF-HEC high triboelectric voltage sensing material.

[0078] Table 1. Technical parameters of the high tribovoltage sensing materials obtained in Examples 1-5

[0079]

[0080] In the triboelectric voltage test, a 5*5cm square piece of HEC-PVDF-HEC high triboelectric voltage sensing material was first cut. Copper foil tape and wires were then attached to the back of the square piece in a grid-like structure to fabricate the positive electrode of the triboelectric nanogenerator. Similarly, the negative electrode of the triboelectric nanogenerator was fabricated using a polytetrafluoroethylene (PTFE) film. The positive and negative electrode materials were connected to an oscilloscope, and a linear motor was used to apply a uniform and stable impact force, causing the positive and negative electrodes to separate, resulting in charge transfer and the generation of triboelectric voltage.

[0081] Table 1 shows the technical parameters of the high triboelectric voltage sensing materials prepared in Examples 1-5. It can be seen that the triboelectric power generation cathode material prepared by the process route provided by this invention benefits from the introduction of aramid nanofibers to enhance its toughness and strength, achieving a mechanical strength in the range of 10-15 MPa. As the concentration of hydroxyethyl cellulose (HEC) increases and the HEC-PVDF-HEC film becomes thicker, its mechanical strength also increases. The triboelectric voltage is significantly affected by the thickness of the hydroxyethyl film; the thicker the cathode material, the stronger the electrostatic coupling charge transfer capability, the more electrons are lost, the greater the potential difference between the positive and negative electrodes, and the greater the triboelectric voltage. Similarly, the wide-bandgap charge-retaining PVDF film effectively improves charge accumulation and transmission efficiency, and also increases the triboelectric voltage output by the material. This structural design not only enhances the overall performance of the material but also improves the output stability and sensitivity of the nano-triboelectric generator.

[0082] Figures 3-7The high triboelectric voltage of the hydroxyethyl cellulose sensing material prepared in Examples 1-5 is used to prepare a 5*5cm square triboelectric generator by using a polytetrafluoroethylene film as the negative electrode. Different output voltages can be generated by applying different magnitudes of force. This device can be used in flexible wearables and can sense different human activities by monitoring the different output voltages.

[0083] This invention also discloses a nano-triboelectric device prepared by connecting a high-triboelectric-voltage hydroxyethyl cellulose sensing material and polytetrafluoroethylene, wherein the microcurrent generated by electrostatic coupling can light up a TENG lamp.

[0084] The above description is merely a preferred embodiment of the present invention and is not intended to limit the technical solution of the present invention in any way. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can be modified and replaced in several simple ways, and these modifications and replacements are all within the scope of protection covered by the claims.

Claims

1. A high triboelectric voltage hydroxyethyl cellulose sensing material, characterized in that, It consists of a three-layer structure, from top to bottom: an upper hydroxyethyl cellulose film, a polyvinylidene fluoride film, and a lower hydroxyethyl cellulose film. The upper and lower hydroxyethyl cellulose films are obtained by casting and drying a mixed dispersion of hydroxyethyl cellulose and aramid nanofibers. The polyvinylidene fluoride film is obtained by electrospinning using a spinning solution containing polyvinylidene fluoride. The high triboelectric voltage hydroxyethyl cellulose sensing material is used as the positive electrode material of the triboelectric nanogenerator.

2. A method for preparing the high triboelectric voltage hydroxyethyl cellulose sensing material as described in claim 1, characterized in that, Includes the following steps: Step 1: Prepare a mixed dispersion of hydroxyethyl cellulose and aramid nanofibers and a spinning solution containing polyvinylidene fluoride; Step 2: The hydroxyethyl cellulose and aramid nanofiber mixed dispersion is used to obtain the lower hydroxyethyl cellulose film by a combination of casting and drying. Polyvinylidene fluoride (PVDF) films are obtained by electrospinning a spinning solution containing PVDF. Step 3: Place the polyvinylidene fluoride film on the upper surface of the dried lower hydroxyethyl cellulose film; Then, a wet upper hydroxyethyl cellulose film was prepared on the upper surface of the polyvinylidene fluoride film by casting a mixed dispersion of hydroxyethyl cellulose and aramid nanofibers; after drying, a three-dimensional intercalated HEC-PVDF-HEC high triboelectric voltage sensing material was obtained.

3. The method for preparing high triboelectric voltage hydroxyethyl cellulose sensing material according to claim 2, characterized in that, In step 1, the preparation method of the mixed dispersion of hydroxyethyl cellulose and aramid nanofibers is as follows: at 45~55℃, 2~3g of hydroxyethyl cellulose powder is dissolved in 200~300mL of aramid nanofiber dispersion for 20~30min to obtain the mixed dispersion of hydroxyethyl cellulose and aramid nanofibers; wherein, the concentration of the mixed dispersion of hydroxyethyl cellulose and aramid nanofibers is 0.010~0.015g / mL.

4. The method for preparing high triboelectric voltage hydroxyethyl cellulose sensing material according to claim 3, characterized in that, The preparation of the aramid nanofiber mixed dispersion is as follows: First, an alkaline solution, para-aramid fibers, and dimethyl sulfoxide are stirred and mixed to obtain dispersion A; wherein, the mass ratio of para-aramid fibers to dimethyl sulfoxide is 2~3:200~300, the solute in the alkaline solution is potassium hydroxide, the concentration of the solute in the alkaline solution is 0.3~0.6g / mL, and the ratio of alkaline solution to para-aramid fibers is 1~2mL:2~3g; Dispersion A was uniformly dispersed in deionized water, and then allowed to stand and filtered to obtain para-aramid nanofiber dispersion B; wherein the volume ratio of water to dispersion A was 1000~1500:50~100, and the concentration of para-aramid nanofiber dispersion was 1%~1.5%.

5. The method for preparing high triboelectric voltage hydroxyethyl cellulose sensing material according to claim 2, characterized in that, In step 1, the spinning solution containing polyvinylidene fluoride is prepared as follows: the spinning solution is obtained by dissolving polyvinylidene fluoride in N,N-dimethylformamide solution.

6. The method for preparing high triboelectric voltage hydroxyethyl cellulose sensing material according to claim 5, characterized in that, The ratio of polyvinylidene fluoride to N,N-dimethylformamide solution is 4~5g:7~9mL, the dissolution temperature is 60~70℃, the rotation speed is 100~200r / min, and the time is 2~3h.

7. The method for preparing high triboelectric voltage hydroxyethyl cellulose sensing material according to claim 2, characterized in that, In step 2, during the preparation of the lower hydroxyethyl cellulose film, the drying temperature is 60~70℃ and the time is 10~12h. After drying, the film thickness of the lower hydroxyethyl cellulose film is 0.06~0.08mm.

8. The method for preparing high triboelectric voltage hydroxyethyl cellulose sensing material according to claim 2, characterized in that, In step 2, during the electrospinning process, the voltage is 15~17kV, the temperature is 35~45℃, the humidity is 65%~75%, the spinning solution spraying rate is 0.008~0.010mL / min, and the time is 6~8h.

9. The method for preparing high triboelectric voltage hydroxyethyl cellulose sensing material according to claim 2, characterized in that, In step 3, the drying process is carried out at a temperature of 60~70℃ for 10~12h, and the film thickness of the upper hydroxyethyl cellulose film after drying is 0.06~0.08mm.

10. A grid-structured triboelectric nanogenerator prepared from the high triboelectric voltage hydroxyethyl cellulose sensing material as described in claim 1.

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