Solid-liquid based triboelectric nanogenerator super-slippery film and its preparation method and application

Abstract

The present invention provides a solid-liquid based triboelectric nanogenerator super-slippery film, a preparation method thereof and an application. The super-slippery film includes an insulating polymer layer, a silica nanoparticle layer and a perfluoropolyether layer. The silica nanoparticle layer is disposed on at least a part of the surface on one side of the insulating polymer layer; the perfluoropolyether layer is disposed on at least a part of the surface of the silica nanoparticle layer. The perfluoropolyether layer includes a perfluoropolyether with a silane end group, and the silane group on the perfluoropolyether with a silane end group is covalently connected to the silica nanoparticles in the silica nanoparticle layer. The surface of this super-slippery film has a large effective area, the contact area between the liquid droplet and the film is large, the acting force is strong, the stability is good, and self-cleaning can be achieved. It can also be used normally in a low-temperature environment. The solid-liquid based triboelectric nanogenerator prepared with this super-slippery film has excellent electrical output performance.

Description

Technical Field

[0001] The present invention belongs to the field of surface modification of solid materials, and particularly relates to a solid-liquid based triboelectric nanogenerator super-slippery film, a preparation method thereof, and an application thereof. Background Art

[0002] With the depletion of petroleum resources and the increasingly severe environmental problems, there is an urgent need to develop green and renewable energy to meet the sustainable development of human society. One idea is to utilize the abundant water resources in nature. Currently, relatively mature technologies include building hydropower stations with dams and collecting tidal energy from the ocean. In addition, a large part of the energy is stored in small but ubiquitous water droplets such as rainwater and dew. For such discontinuous and intermittent energy, a solid / liquid based triboelectric nanogenerator can be used to collect it. However, for existing solid / liquid based triboelectric nanogenerators, since the solid phase is mostly designed as a hydrophobic or superhydrophobic surface, water droplets will bounce on the surface. Therefore, the most efficient power generation method for it is the spreading contact type. But for the spreading contact type, only when the water droplets touch the top electrode during the spreading process can charge transfer occur, and the output of water droplets that are too far or too close is not high, which results in a relatively small effective area of the material surface. In addition, the superhydrophobicity of existing materials makes the contact area between water droplets and the material surface small, the contact time short, the acting force small, the stability poor, and there are air cavities on the material surface, all of which will affect the final electrical output performance.

[0003] Therefore, the solid phase of existing solid / liquid based triboelectric nanogenerators needs to be improved. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems in the related art to some extent. For this reason, an object of the present invention is to provide a solid-liquid based triboelectric nanogenerator super-slippery film, a preparation method thereof, and an application thereof. The super-slippery film has a large effective surface area, a large contact area between water droplets and the film, a strong acting force, good stability, and can achieve self-cleaning, and can also be used normally in a low-temperature environment. The solid-liquid based triboelectric nanogenerator prepared with this super-slippery film has excellent electrical output performance.

[0005] In one aspect of the present invention, a solid-liquid based triboelectric nanogenerator super-slippery film is provided. According to an embodiment of the present invention, the super-slippery film includes:

[0006] An insulating polymer layer;

[0007] A silica nanoparticle layer, which is provided on at least a part of the surface on one side of the insulating polymer layer;

[0008] A perfluoropolyether layer is provided on at least a part of the surface of the silica nanoparticle layer. The perfluoropolyether layer includes a perfluoropolyether with a silane end group, and the silane group on the perfluoropolyether with a silane end group is covalently bonded to the silica nanoparticles in the silica nanoparticle layer.

[0009] The super-slippery thin film according to the above embodiments of the present invention includes an insulating polymer layer, a silica nanoparticle layer, and a perfluoropolyether layer. The insulating polymer layer separates the surface layer of the thin film from the bottom electrode. The silica nanoparticle layer is provided on at least a part of the surface on one side of the insulating polymer layer. The perfluoropolyether layer is provided on at least a part of the surface of the silica nanoparticle layer. The perfluoropolyether includes a perfluoropolyether with a silane end group, and the silane group on the perfluoropolyether with a silane end group is covalently bonded to the silica in the silica nanoparticle layer, thereby forming a stable thin film structure. And the silica is a semiconductor material, and the covalent bonding mode between the silane group and the silica is beneficial to the transfer of electrons on the thin film. At the same time, on the one hand, since the surface of the perfluoropolyether layer is very flat and has a small roughness, it not only avoids the formation of air cavities on the surface of the perfluoropolyether layer, makes the liquid droplets contact the perfluoropolyether layer more fully, improves the force and stability between the liquid droplets and the material, but also the contact angle of the liquid droplets on the perfluoropolyether layer is small. Specifically, the contact angle is 70° - 120°, which further increases the contact area between the liquid droplets and the perfluoropolyether layer. On the other hand, the perfluoropolyether layer has super-slippery properties, and the liquid droplets can slide on the surface of the perfluoropolyether layer, prolonging the contact time between the liquid droplets and the perfluoropolyether layer. Specifically, the sliding angle of the liquid droplets on the perfluoropolyether layer is not greater than 10°. Therefore, the liquid droplets can drip within a large range and then slide to the electrode, significantly increasing the effective surface area of the thin film. The inventors also found that due to the super-slippery properties of the perfluoropolyether layer, the force between pollutants and other impurities and the surface of the perfluoropolyether layer is small, and the water droplets can carry away or loosen the pollutants attached to the surface when flowing through the surface, realizing the self-cleaning effect. At the same time, since impurities are not easily attached to the surface, the nucleation sites of ice crystals are reduced, thereby preventing the growth of ice crystals. Specifically, in an environment of -13°C, the liquid droplets can still continuously slide. Even when frozen, the force between the ice and the surface is small and can be easily removed from the surface. Thus, the super-slippery thin film has a large effective surface area, a large contact area, strong force, good stability between the liquid droplets and the thin film, can realize self-cleaning, and can be used normally in a low-temperature environment. The solid-liquid based triboelectric nanogenerator prepared with this super-slippery thin film has excellent electrical output performance.

[0010] In addition, the solid-liquid based triboelectric nanogenerator super-slippery thin film according to the above embodiments of the present invention may also have the following properties:

[0011] In some embodiments of the present invention, the thickness of the silica nanoparticle layer is 100 nm - 1.5 μm. Thereby, it is beneficial to the transfer of electrons on the thin film.

[0012] In some embodiments of the present invention, the thickness of the perfluoropolyether layer is 2 μm - 30 μm. Thus, the surface of the perfluoropolyether layer is super-slippery.

[0013] In some embodiments of the present invention, the thickness of the insulating polymer layer is 0.2 μm - 2 μm. Thus, it can achieve good insulation performance.

[0014] In some embodiments of the present invention, the particle size of the silicon dioxide nanoparticles is 100 nm - 200 nm. Thus, it is beneficial for the transfer of electrons on the thin film.

[0015] In some embodiments of the present invention, the insulating polymer in the insulating polymer layer includes at least one of Teflon, polytetrafluoroethylene, and perfluoroethylene propylene copolymer.

[0016] In some embodiments of the present invention, the surface roughness of the perfluoropolyether layer is not greater than 50 nm. Thus, the contact area between the droplet and the perfluoropolyether layer is increased, and the contact time is extended.

[0017] In the second aspect of the present invention, the present invention provides a method for preparing the above-mentioned solid-liquid based triboelectric nanogenerator super-slippery thin film. According to the embodiments of the present invention, the method includes:

[0018] (1) Forming an insulating polymer layer on the conductive substrate;

[0019] (2) Forming a silicon dioxide nanoparticle layer on the insulating polymer layer;

[0020] (3) Forming a perfluoropolyether layer on the silicon dioxide nanoparticle layer so as to form a super-slippery thin film on the conductive substrate.

[0021] Thus, by using this method, a super-slippery thin film with a large effective surface area, a large contact area with droplets, strong acting force, and good stability can be prepared. Moreover, the materials used in this method are easily available, the cost is relatively low, and the operation is simple.

[0022] In addition, the method for preparing the solid-liquid based triboelectric nanogenerator super-slippery thin film according to the above embodiments of the present invention may further have the following technical features:

[0023] In some embodiments of the present invention, in step (1), the insulating polymer and the solvent are mixed to form an insulating polymer solution, and then the insulating polymer solution is applied on the conductive substrate, thereby forming an insulating polymer layer on the conductive substrate.

[0024] In some embodiments of the present invention, the concentration of the insulating polymer in the insulating polymer solution is 1 g / L - 70 g / L, preferably 28 g / L - 56 g / L.

[0025] In some embodiments of the present invention, in step (2), a solution containing silica nanoparticles is electro-deposited on the insulating polymer layer to form a silica nanoparticle layer on the insulating polymer layer; wherein, the voltage of the electro-deposition is 1V - 4V, and the current of the electro-deposition is 0.0001A / cm 2 - 0.001A / cm 2 , preferably 0.0001A / cm 2 - 0.0005A / cm 2 , and the time of the electro-deposition is 2min - 5min. Thus, a silica nanoparticle layer with a flat and uniform surface can be formed on the insulating polymer layer.

[0026] In some embodiments of the present invention, in step (2), the method for preparing the silica nanoparticles is as follows: tetraethyl orthosilicate, methyltriethoxysilane and a solvent are mixed to obtain silica nanoparticles, wherein the solvent includes deionized water and ethanol. Thus, silica nanoparticles can be prepared.

[0027] In some embodiments of the present invention, in step (3), the substrate material obtained in step (2) is impregnated in a perfluoropolyether electronic fluorination liquid solution to form a perfluoropolyether layer on the silica nanoparticle layer.

[0028] In some embodiments of the present invention, the impregnation time is 1min - 90min, preferably 5min - 60min. Thus, a perfluoropolyether layer with a super-slippery surface and a uniform thickness can be formed on the silica nanoparticle layer.

[0029] In some embodiments of the present invention, the volume concentration of the perfluoropolyether in the perfluoropolyether electronic fluorination liquid solution is 0.5μL / mL - 10μL / mL, preferably 1μL / mL - 10μL / mL.

[0030] In the third aspect of the present invention, the present invention provides a triboelectric nanogenerator. According to the embodiments of the present invention, the triboelectric nanogenerator includes a top electrode, a power generation thin film and a bottom electrode. The top electrode is suspended above the power generation thin film, the bottom electrode is grounded, the power generation thin film includes the above-mentioned solid-liquid based triboelectric nanogenerator super-slippery thin film or the solid-liquid based triboelectric nanogenerator super-slippery thin film prepared by the above method, and the bottom electrode is connected to the insulating polymer layer.

[0031] The additional aspects and advantages of the present invention will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present invention. Description of the Drawings

[0032] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of embodiments in conjunction with the accompanying drawings, where:

[0033] Figure 1 is a schematic diagram of the super-slippery thin film structure of an embodiment of the present invention;

[0034] Figure 2 is a schematic diagram of the triboelectric nanogenerator structure of an embodiment of the present invention;

[0035] Figure 3 is a scanning electron microscope photograph of the morphology of the super-slippery thin film of Embodiment 1 of the present invention;

[0036] Figure 4 is a contact angle and sliding angle diagram of the super-slippery thin film of Embodiment 1 of the present invention with water droplets (2 μL) in air;

[0037] Figure 5 is a voltage output test result diagram of the super-slippery thin film of Embodiment 1 of the present invention for power generation;

[0038] Figure 6 is a self-cleaning experimental result diagram of the super-slippery thin film of Embodiment 1 of the present invention. Detailed Embodiments

[0039] The embodiments of the present invention are described in detail below, which are intended to explain the present invention and should not be construed as limiting the present invention.

[0040] In one aspect of the present invention, the present invention provides a solid-liquid based triboelectric nanogenerator super-slippery thin film. According to an embodiment of the present invention, as Figure 1 shown, the super-slippery thin film includes an insulating polymer layer 100, a silica nanoparticle layer 200, and a perfluoropolyether layer 300.

[0041] According to an embodiment of the present invention, referring to Figure 1 , the thickness of the insulating polymer layer 100 is 0.2 μm - 2 μm. The insulating polymer layer 100 separates the surface layer of the thin film from the bottom electrode and plays an insulating role. The inventors found that if the thickness of the insulating polymer layer 100 is too small, the overall mechanical properties are limited, and if damage or cracks occur during use, it cannot play a good role in blocking charges; if the thickness of the insulating polymer layer 100 is too large, the electrostatic induction performance is limited. Therefore, the present application uses an insulating polymer layer 100 with a thickness of 0.2 μm - 2 μm, which can achieve good insulation performance. It should be noted that the insulating polymer in the insulating polymer layer 100 is a conventional material in the art, and those skilled in the art can select according to actual situations. For example, the insulating polymer includes at least one of Teflon, polytetrafluoroethylene, and perfluoroethylene propylene copolymer.

[0042] According to an embodiment of the present invention, referring toFigure 1 , a silica nanoparticle layer 200 is provided on at least a partial surface of one side of the insulating polymer layer 100. The silica nanoparticles serve as a semiconductor material, which is conducive to the transmission of electrons. Further, the thickness of the silica nanoparticle layer 200 is 100 nm - 1.5 μm. The inventors found that if the thickness of the silica nanoparticle layer 200 is too small, part of the perfluoropolyether directly grows on the insulating polymer, resulting in the loss of the original function of the insulating polymer; if the thickness of the silica nanoparticle layer 200 is too large, charge shielding may be caused. Therefore, in this application, the silica nanoparticle layer 200 with a thickness of 100 nm - 1.5 μm is adopted, which is conducive to the transfer of electrons on the thin film.

[0043] According to an embodiment of the present invention, the particle size of the silica nanoparticles is 100 nm - 200 nm. The inventors found that if the particle size of the silica nanoparticles is less than 100 nm, the nanoparticles are prone to agglomeration and it is difficult to be uniformly dispersed on the surface of the insulating polymer; if the particle size of the silica nanoparticles is greater than 200 nm, it will lead to too large surface roughness, which has an adverse effect on the surface super-slippery property, and the larger particles are likely to cause the silica layer to be too thick, thus causing charge shielding. Therefore, in this application, the silica nanoparticles with a particle size of 100 nm - 200 nm are adopted, and a layer of semiconductor silica nanospheres can be uniformly constructed on the surface of the insulating polymer on the premise of ensuring that the roughness is as small as possible and the thickness is as thin as possible.

[0044] According to an embodiment of the present invention, with reference to Figure 1, a perfluoropolyether layer 300 is provided on at least a part of the surface of the silica nanoparticle layer 200. The perfluoropolyether includes a perfluoropolyether with a silane end group, and the silyl group on the perfluoropolyether with a silane end group is covalently bonded to the silica nanoparticles in the silica nanoparticle layer 200. The inventor found that the covalent bonding of the silyl group on the perfluoropolyether with a silane end group to the silica in the silica nanoparticle layer can form a stable thin film structure. Moreover, since silica is a semiconductor material, the covalent bonding mode of the silyl group to silica is conducive to the transfer of electrons on the thin film. At the same time, on the one hand, due to the very flat surface of the perfluoropolyether layer 300 and small roughness, it not only avoids the formation of air cavities on the surface of the perfluoropolyether layer 300, making the liquid droplet contact the perfluoropolyether layer 300 more fully, improving the force and stability between the liquid droplet and the material, but also the contact angle of the liquid droplet on the perfluoropolyether layer 300 is small. Specifically, the contact angle is 70° - 120°, further increasing the contact area between the liquid droplet and the perfluoropolyether layer 300. On the other hand, the perfluoropolyether layer 300 has a super-slippery property, and the liquid droplet can slide on the surface of the perfluoropolyether layer 300, extending the contact time between the liquid droplet and the perfluoropolyether layer 300. Specifically, the sliding angle of the liquid droplet on the perfluoropolyether layer 300 is not greater than 10°. Therefore, the liquid droplet can drip within a large range and then slide to the electrode, significantly increasing the effective surface area of the thin film.

[0045] According to an embodiment of the present invention, referring to Figure 1 , the thickness of the perfluoropolyether layer 300 is 2μm - 30μm. The inventor found that if the thickness of the perfluoropolyether layer 300 is too small, less negative charge is generated on the solid surface; if the thickness of the perfluoropolyether layer 300 is too large, the liquid-like layer is thicker, and the mechanical properties and durability of the solid-phase surface are limited. Thus, by using the perfluoropolyether layer 300 with a thickness of 2μm - 30μm in this application, it is possible to ensure the mechanical properties and durability of the solid-phase surface while generating as much negative charge as possible. Further, the surface roughness of the perfluoropolyether layer is not greater than 50nm. The inventor found that the smaller the surface roughness of the perfluoropolyether layer, the fewer air cavities on the surface, reducing the interfacial shielding, and the material will contact the liquid droplet more fully. Thus, the surface roughness of the perfluoropolyether layer in this application is not greater than 50nm, increasing the contact area between the liquid droplet and the perfluoropolyether layer and extending the contact time.

[0046] Therefore, the super-slippery thin film has a large effective surface area, a large contact area between the liquid droplet and the thin film, strong force, good stability, and can achieve self-cleaning, and can also be used normally in a low-temperature environment. The solid-liquid based triboelectric nanogenerator prepared with this super-slippery thin film has excellent electrical output performance.

[0047] In the second aspect of the present invention, the present invention proposes a method for preparing the above-mentioned solid-liquid based triboelectric nanogenerator super-slippery thin film. According to an embodiment of the present invention, the method includes:

[0048] S100: Form an insulating polymer layer on a conductive substrate

[0049] In this step, an insulating polymer layer is formed on the conductive substrate. Specifically, an insulating polymer and a solvent are mixed to form an insulating polymer solution, and then the insulating polymer solution is applied to the conductive substrate, thereby forming an insulating polymer layer on the conductive substrate. Further, the concentration of the insulating polymer in the insulating polymer solution is 1 g / L - 70 g / L, preferably 28 g / L - 56 g / L. Thus, a relatively flat insulating polymer thin film can be obtained. It should be noted that the conductive substrate and the solvent are both conventional materials in the art, and those skilled in the art can select according to the actual situation. For example, the conductive substrate includes an ITO glass substrate, and the solvent includes acetone. The conductive substrate can be cleaned with a mixed solution of ethanol and acetone (volume ratio 1:1) before use. At the same time, the method of applying the insulating polymer solution to the conductive substrate is also a conventional method in the art, such as the drop-casting method.

[0050] S200: Form a silica nanoparticle layer on the insulating polymer layer

[0051] In this step, a silica nanoparticle layer is formed on the insulating polymer layer. Specifically, a solution containing silica nanoparticles is electrodeposited on the insulating polymer layer, thereby forming a silica nanoparticle layer on the insulating polymer layer. Further, the voltage of the electrodeposition is 1 V - 4 V, and the current of the electrodeposition is 0.0001 A / cm 2 -0.001 A / cm 2 Preferably 0.0001 A / cm 2 -0.0005 A / cm 2 , and the time of the electrodeposition is 2 min - 5 min. Those skilled in the art can understand that silica nanoparticles are conventional materials in the art, and those skilled in the art can use existing methods to prepare silica nanoparticles or select existing silica nanoparticles. For example, tetraethyl orthosilicate, methyltriethoxysilane, and a solvent are mixed to obtain silica nanoparticles. Among them, the solvent includes deionized water and ethanol. Specifically, the solvent is a mixed solution of deionized water with pH = 13 and ethanol (deionized water and ethanol in equimolar amounts), and the molar ratio of tetraethyl orthosilicate to triethoxymethylsilane is 1:1 - 30:1, preferably 5:1 - 15:1. It should be noted that the method of forming a silica nanoparticle layer on the insulating polymer layer can not only use the electrodeposition method, but also other conventional methods, such as the vapor deposition method, and those skilled in the art can select according to the actual situation.

[0052] S300: Form a perfluoropolyether layer on the silica nanoparticle layer

[0053] In this step, a perfluoropolyether layer is formed on the silica nanoparticle layer. Specifically, perfluoropolyether is uniformly dissolved in an electronic fluorinated liquid, and the substrate material prepared in step 200 is immersed in the above-mentioned electronic fluorinated liquid, so that perfluoropolyether molecular chains are covalently modified on the surface of SiO2, and part of the perfluoropolyether is embedded into the molecular gaps of SiO2, thereby forming a super-slippery film on the conductive substrate. Further, the immersion time is 1 min - 90 min, preferably 5 min - 60 min. Thus, the reaction can be ensured to proceed completely. The volume concentration of perfluoropolyether in the perfluoropolyether electronic fluorinated liquid solution is 0.5 μL / mL - 10 μL / mL, preferably 1 μL / mL - 10 μL / mL. Thus, as much reaction as possible can occur on the premise of ensuring the solubility of perfluoropolyether.

[0054] Thus, by using this method, a super-slippery film with a large effective surface area, a large contact area with droplets, strong interaction force, good stability, and self-cleaning ability can be prepared. Moreover, the materials used in this method are easily available, the cost is low, and the operation is simple. It should be noted that the characteristics and advantages described for the above-mentioned solid-liquid based triboelectric nanogenerator super-slippery film also apply to this method, and will not be elaborated here.

[0055] In the third aspect of the present invention, the present invention proposes a triboelectric nanogenerator. According to an embodiment of the present invention, referring to Figure 2 , the triboelectric nanogenerator includes a top electrode 10, a power generation film 20, and a bottom electrode 30. The top electrode 10 is suspended above the power generation film 20, the bottom electrode 30 is grounded, and the power generation film 30 includes the above-mentioned solid-liquid based triboelectric nanogenerator super-slippery film or the solid-liquid based triboelectric nanogenerator super-slippery film prepared by the above method. The bottom electrode 30 is connected to the insulating polymer layer. Thus, the triboelectric nanogenerator has excellent electrical output performance. Further, the distance between the top electrode 10 suspended above the power generation film 20 is 2 mm - 1.5 cm. Thus, the suspended design can avoid the top electrode from being electrostatically induced to carry charges on the film surface in advance, and the suspended distance of 2 mm - 1.5 cm can enable the top electrode to contact the water droplets sliding down. It should be noted that the characteristics and advantages described for the above-mentioned solid-liquid based triboelectric nanogenerator super-slippery film and its preparation method also apply to this triboelectric nanogenerator, and will not be elaborated here.

[0056] Next, the present invention will be described with reference to specific embodiments. It should be noted that these embodiments are merely descriptive and do not limit the present invention in any way.

[0057] Example 1

[0058] (1) Add 0.63 g of polytetrafluoroethylene and 15 mL of acetone into a 50 mL beaker, stir evenly to obtain a mixed solution, and the mass concentration of Teflon in this mixed solution is 42 g / L. Prepare a flat insulating polymer layer on the surface of the cleaned ITO glass by the drop-casting method, and the thickness of the insulating polymer layer is 1 μm.

[0059] (2) At room temperature, add 2.39 mL of tetraethyl orthosilicate and 2.14 mL of triethoxymethylsilane into a 100 mL beaker, stir evenly to obtain a first mixed solution; add 16.76 mL of pH = 13 water and 54.19 mL of ethanol into a 100 mL beaker, stir evenly to obtain a second mixed solution; the molar ratio of deionized water with pH = 13 (equimolar with ethanol) to tetraethyl orthosilicate (equimolar with triethoxymethylsilane) is 9:1; place the first mixed solution in an ice-water bath, and slowly add the second mixed solution to the first mixed solution.

[0060] (3) Use the ITO glass material obtained in step (1) as the anode and a copper sheet as the cathode, and electro-deposit in the mixed solution obtained in step (2) for 3.5 min, keep the current at 0.0001 A and the voltage at 2.7 V, so as to form a silica nanoparticle layer on the insulating polymer layer, the thickness of the silica nanoparticle layer is 600 nm, and the particle size of the silica nanoparticles is 150 nm.

[0061] (4) Take out the glass substrate material in step (3), dry it in the air, and soak it in a 3 μL / mL perfluoropolyether electronic fluorination liquid solution for 30 min to obtain a triboelectric nanogenerator super-slippery film with self-cleaning properties; the surface perfluoropolyether covalent modification fills the gaps between SiO2 particles, and the whole is uniform and flat. As Figure 3 shown, a 30 μm thick perfluoropolyether lubricating layer is formed on the surface, and the surface roughness of the perfluoropolyether layer is 45 nm.

[0062] Measure the contact angle between the super-slippery power generation film obtained in Example 1 and 2 μL water droplets in the air, which is 85.0°, presenting a hemispherical shape, and the sliding angle is about 4.0°, as Figure 4 shown.

[0063] Test the voltage output of the super-slippery power generation film obtained in Example 1. Suspend the top electrode to collect the charges generated by the friction between the liquid droplets and the surface, and generate a potential difference with another grounded electrode, and obtain a peak voltage of 15 V - 16 V, as Figure 5 shown.

[0064] As Figure 6As shown in the figure, a self-cleaning experiment was carried out on the super-slippery power generation thin film obtained in Example 1. Using ultrafine copper powder and carbon nanotubes as representative pollutants respectively, it was found that water droplets could easily wash away the ultrafine copper powder and carbon nanotubes loosely attached to the surface, indicating good self-cleaning performance.

[0065] Example 2

[0066] The main differences between Example 2 and Example 1 are as follows:

[0067] (3) Using the ITO glass obtained in step (1) as the anode and a copper sheet as the cathode, electro-deposit for 3.5 min in the mixed solution obtained in step (2), keeping the current not exceeding 0.0001 A and the voltage at 2.5 V, so as to form a layer of silica nanoparticles on the insulating polymer layer. The thickness of the silica nanoparticle layer is 1 μm, and the particle size of the silica nanoparticles is 200 nm.

[0068] (4) Take out the glass substrate material in step (3), dry it in the air, and soak it in a 1 μL / mL perfluoropolyether electronic fluorination liquid solution for 5 min to obtain a triboelectric nanogenerator super-slippery thin film with self-cleaning properties. The perfluoropolyether covalent modification part on the surface fills the gaps between the SiO2 particles, and a 20-μm-thick perfluoropolyether lubricating layer is formed on the surface. The surface roughness of the perfluoropolyether layer is 50 nm.

[0069] Measure the contact angle between the super-slippery power generation thin film obtained in Example 2 and a 2-μL water droplet in the air, which is 72.3°, and the hydrophilicity increases, and the sliding angle is about 10°; test the voltage output of the super-slippery power generation thin film obtained in Example 2. Suspend the top electrode to collect the charges generated by the friction between the liquid droplet and the surface, and generate a potential difference with another grounded electrode, and obtain a peak voltage of 12-13 V.

[0070] Carry out a self-cleaning experiment on the super-slippery power generation thin film obtained in Example 2. Using ultrafine copper powder and carbon nanotubes as representative pollutants respectively, it was found that water droplets could easily wash away the ultrafine copper powder and carbon nanotubes loosely attached to the surface, indicating good self-cleaning performance.

[0071] Example 3

[0072] The main differences between Example 3 and Example 1 are:

[0073] (3) Using the ITO glass obtained in step (1) as the anode and a copper sheet as the cathode, electro-deposit for 4 min in the mixed solution obtained in step (2), keeping the current at 0.0003 A and the voltage at 2.9 V, so as to form a layer of silica nanoparticles on the insulating polymer layer. The thickness of the silica nanoparticle layer is 200 nm, and the particle size of the silica nanoparticles is 100 nm.

[0074] The contact angle between the super-slippery power generation thin film obtained in Example 3 and 2 μL of water droplets was measured in air to be 101.5°, indicating an increase in hydrophilicity, and the sliding angle was approximately 9°. The voltage output of the super-slippery power generation thin film obtained in Example 3 was tested. The top electrode was suspended to collect the charges generated by the friction between the droplets and the surface, creating a potential difference with another grounded electrode, and a peak voltage of 13 - 14 V was obtained.

[0075] A self-cleaning experiment was conducted on the super-slippery power generation thin film obtained in this example. Using ultrafine copper powder and carbon nanotubes as representative pollutants respectively, it was found that water droplets could easily wash away the ultrafine copper powder and carbon nanotubes loosely attached to the surface, indicating good self-cleaning performance.

[0076] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0077] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A solid-liquid based triboelectric nanogenerator super-slippery film, characterized in that, Comprising: An insulating polymer layer; A silica nanoparticle layer provided on at least a part of the surface on one side of the insulating polymer layer; A perfluoropolyether layer provided on at least a part of the surface of the silica nanoparticle layer, the perfluoropolyether layer comprising a perfluoropolyether with a silane end group, and the silicon alkyl group on the perfluoropolyether with a silane end group is covalently bonded to the silica nanoparticles in the silica nanoparticle layer.

2. The solid-liquid-based triboelectric nanogenerating super-slippery film according to claim 1, characterized in that, The thickness of the silica nanoparticle layer is 100 nm - 1.5 μm; Optionally, the thickness of the perfluoropolyether layer is 2 μm - 30 μm; Optionally, the thickness of the insulating polymer layer is 0.2 μm - 2 μm; Optionally, the particle size of the silica nanoparticles is 100 nm - 200 nm; Optionally, the insulating polymer in the insulating polymer layer includes at least one of Teflon, polytetrafluoroethylene, and perfluoroethylene propylene copolymer.

3. The solid-liquid based triboelectric nanogenerating super-slippery film according to claim 1, characterized in that, The surface roughness of the perfluoropolyether layer is not greater than 50 nm; Optionally, the contact angle of the liquid droplet on the surface of the perfluoropolyether layer is 70° - 120°, and the sliding angle is not greater than 10°.

4. A method for preparing the solid-liquid based triboelectric nanogenerative super-slippery film according to any one of claims 1-3, characterized in that, Comprising: (1) Forming an insulating polymer layer on a conductive substrate; (2) Forming a silica nanoparticle layer on the insulating polymer layer; (3) Forming a perfluoropolyether layer on the silica nanoparticle layer so as to form a super-slippery thin film on the conductive substrate.

5. The method according to claim 4, characterized in that, In step (1), an insulating polymer and a solvent are mixed to form an insulating polymer solution, and then the insulating polymer solution is applied to the conductive substrate, thereby forming an insulating polymer layer on the conductive substrate; Optionally, the concentration of the insulating polymer in the insulating polymer solution is 1 g / L - 70 g / L.

6. The method according to claim 5, characterized in that The concentration of the insulating polymer in the insulating polymer solution is 28 g / L - 56 g / L.

7. The method according to claim 4, characterized in that, In step (2), a solution containing silica nanoparticles is electrodeposited on the insulating polymer layer, thereby forming a silica nanoparticle layer on the insulating polymer layer; Among them, the voltage of the electrodeposition is 1V - 4V, and the current of the electrodeposition is 0.0001A / cm 2 - 0.001A / cm 2 .

8. The method according to claim 7, characterized in that The current of the electro-deposition is 0.0001 A / cm 2 -0.0005 A / cm 2 , and the time of the electro-deposition is 2 min - 5 min.

9. The method according to claim 4, wherein In step (2), the preparation method of the silica nanoparticles is as follows: Tetraethyl orthosilicate, methyltriethoxysilane, and a solvent are mixed to obtain silica nanoparticles, wherein the solvent includes deionized water and ethanol.

10. The method according to claim 4, characterized in that, In step (3), the substrate material obtained in step (2) is impregnated in a perfluoropolyether electronic fluorination liquid solution so as to form a perfluoropolyether layer on the silica nanoparticle layer.

11. The method according to claim 10, characterized in that, The impregnation time is 1 min - 90 min; Optionally, the volume concentration of the perfluoropolyether in the perfluoropolyether electronic fluorination liquid solution is 0.5 μL / mL - 10 μL / mL.

12. The method according to claim 11, wherein The impregnation time is 5 min - 60 min, and / or the volume concentration of the perfluoropolyether in the perfluoropolyether electronic fluorination liquid solution is 1 μL / mL - 10 μL / mL.

13. A triboelectric nanogenerator, characterized in that, It includes a top electrode, a power generation thin film, and a bottom electrode. The top electrode is suspended above the power generation thin film, and the bottom electrode is grounded. The power generation thin film includes the solid-liquid based triboelectric nanogenerator ultra-slippery thin film described in any one of claims 1-3 or the solid-liquid based triboelectric nanogenerator ultra-slippery thin film prepared by the method described in any one of claims 4-12. The bottom electrode is in contact with the insulating polymer layer.

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