Diamine monomer cross-linked modified fluorine-containing ferroelectric polymer, preparation method and device

Abstract

The present invention relates to the technical field of dielectric materials, and in particular to a diamine monomer cross-linked modified fluorine-containing ferroelectric polymer, a preparation method, and a device. The components of the diamine monomer cross-linked modified fluorine-containing ferroelectric polymer include a semi-crystalline thermoplastic fluorine-containing ferroelectric polymer and a diamine cross-linking agent; the semi-crystalline thermoplastic fluorine-containing ferroelectric polymer is polyvinylidene fluoride and its copolymer derivatives with ferroelectricity; the diamine cross-linking agent is a short-chain diamine containing a rigid structure; the mass fraction of the diamine cross-linking agent compared to the overall mass fraction is 0.25%-10%. The film prepared by the present invention meets the application requirements of improving the dielectric constant under high electric field, reducing dielectric loss, reducing leakage current, and improving breakdown field strength.

Description

Technical Field

[0001] The present invention relates to the technical field of dielectric materials, and in particular to a diamine monomer cross-linked modified fluorine-containing ferroelectric polymer, a preparation method and a device. Background Art

[0002] Film capacitors based on polymer dielectrics play an irreplaceable role in the electrical and electronic fields due to their advantages such as fast charge and discharge speeds, high power density, good voltage resistance, self-healing properties, and chemical corrosion resistance. With the increasing demand for miniaturization and lightweight applications of electronic devices, higher requirements are being placed on the energy storage density of polymer dielectrics. Compared with increasing the dielectric constant, increasing the operating voltage of the capacitor has a more significant effect on improving energy density. However, under high electric fields, carriers are more likely to obtain sufficient energy to induce leakage current, which is converted into Joule heat and generates large conductivity losses. This not only significantly reduces the charge and discharge efficiency, but also significantly reduces the breakdown field strength, which in turn leads to failure and damage of power equipment. Therefore, in order to improve energy storage density, polymer dielectrics must not only possess excellent dielectric properties such as high dielectric constant and low dielectric loss, but also low conductivity loss and high breakdown field strength to ensure good charge and discharge efficiency and high discharge energy density.

[0003] At present, polyvinylidene fluoride (PVDF) and its copolymer derivatives, such as poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)), poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)), poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) (P(VDF-TrFE-CFE)), and other fluorine-containing ferroelectric polymers, have relatively high dielectric constants and have become the preferred materials for flexible electronics and sensors. It has five crystalline phases - α, β, γ, δ, and ε. The β phase has a fully anti-planar zigzag conformation, with hydrogen atoms and fluorine atoms in opposite directions. It has the highest dipole moment and exhibits spontaneous polarization, ferroelectricity, and piezoelectricity. The current mainstream method is to dope nanofillers into fluoropolymers to further control their crystal structure and ferroelectric properties. However, the efficacy of PVDF composites is significantly affected by the ratio of filler to the existing β phase. In addition, due to the poor compatibility of the filler with PVDF and poor dispersion of the filler, agglomeration will occur, resulting in a significant reduction in the breakdown field strength. Therefore, it is of great application value to study new modification methods of fluorine-containing ferroelectric polymers with excellent dielectric energy storage properties. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a diamine monomer cross-linked modified fluorine-containing ferroelectric polymer, a preparation method and a device.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0006] In the first aspect, a diamine monomer cross-linked modified fluorine-containing ferroelectric polymer is provided, the components of which include a semi-crystalline thermoplastic fluorine-containing ferroelectric polymer and a diamine cross-linking agent; the semi-crystalline thermoplastic fluorine-containing ferroelectric polymer is polyvinylidene fluoride and its copolymer derivatives with ferroelectricity; the diamine cross-linking agent is a short-chain diamine containing a rigid structure; the mass fraction of the diamine cross-linking agent compared to the total is 0.25%-10%.

[0007] Furthermore, the semi-crystalline thermoplastic fluorine-containing ferroelectric polymer imparts film-forming properties to the uncrosslinked film (B-stage film), toughness to the lightly crosslinked polymer film, and basic dielectric and energy storage properties. The semi-crystalline thermoplastic fluorine-containing ferroelectric polymer is characterized by ferroelectric polyvinylidene fluoride and its copolymer derivatives, including but not limited to polyvinylidene fluoride (PVDF), poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)), poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)), and poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) (P(VDF-TrFE-CFE)). The molecular structures of some thermoplastic fluorine-containing ferroelectric polymers are as follows:

[0008]

[0009]

[0010] Furthermore, diamine crosslinkers are used to lightly crosslink the molecular backbone of PVDF and its derivative copolymers. The diamine monomer is characterized by a short-chain diamine containing a rigid structure such as a benzene ring. These include, but are not limited to, at least one of diaminodiphenylmethane (DDM), diaminodiphenyl sulfone (DDS), 4,4'-diaminodiphenyl ether (ODA), bis[4-(4-aminophenoxy)phenyl]sulfone (BAPS), 2,2-bis[4-(3-aminophenoxy)phenyl]sulfone (MBAPS), 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (HFBAPP), 9,9-bis(3-fluoro-4-aminophenyl)fluorene (FFDA), and 2,2'-bis(trifluoromethyl)diaminobiphenyl (BTMB). The molecular structures of some diamine crosslinkers are as follows:

[0011]

[0012]

[0013] Furthermore, the mass fraction of the diamine cross-linking agent is 0.5%-5% compared to the total mass fraction.

[0014] In a second aspect, a method for preparing a fluorine-containing ferroelectric polymer cross-linked and modified by a diamine monomer is provided, comprising the following steps:

[0015] A semi-crystalline thermoplastic fluorine-containing ferroelectric polymer and a diamine monomer are subjected to a heat-induced high-temperature cross-linking reaction to prepare a lightly cross-linked fluorine-containing ferroelectric polymer film; first, the semi-crystalline thermoplastic fluorine-containing ferroelectric polymer and the diamine monomer are blended and prepared into an uncross-linked film by a solution casting method; then, the film is treated at high temperature under a vacuum environment to induce a cross-linking reaction between the diamine monomer and the fluorine-containing ferroelectric polymer, thereby forming a fluorine-containing ferroelectric polymer film with a lightly cross-linked network.

[0016] Furthermore, the method specifically includes the following sub-steps:

[0017] S1. The semi-crystalline thermoplastic fluorine-containing ferroelectric polymer and the diamine crosslinker are dissolved in an organic solvent and heated to dissolve to obtain a slurry composition having a solid content of 0.1wt%-20wt%;

[0018] S2. The slurry is formed into a film by solution casting; specifically, the slurry is evenly coated on a glass substrate and baked at 60-90 ℃ to evaporate the solvent as much as possible to obtain an uncrosslinked film;

[0019] S3. After the solvent is evaporated, the glass substrate is subjected to a cross-linking reaction at multiple temperature ranges between 100°C and 250°C to obtain a cross-linked film;

[0020] S4. Place the glass substrate with the cross-linked film in deionized water to peel off the film, and dry the peeled film at high temperature to obtain a diamine monomer cross-linked modified fluorine-containing ferroelectric polymer film.

[0021] Furthermore, in step S1, the solid content of the slurry is 1 wt%-2 wt%.

[0022] Furthermore, in step S3, the cross-linking process is 120°C×10h+240°C×1h.

[0023] In a third aspect, a device is provided, which includes a fluorine-containing ferroelectric polymer cross-linked and modified by a diamine monomer, and is used as a thin film capacitor.

[0024] The beneficial effects of the present invention are:

[0025] The prepared diamine monomer cross-linked modified fluorine-containing ferroelectric polymer has the following characteristics: excellent dielectric energy storage performance, showing excellent energy storage performance under a strong electric field above 400MV / m, for example, high breakdown field strength (E b ≥500MV / m), high dielectric constant (k≥9) and high discharge energy density (U e ≥11.6J / cm 3 ); and the preparation method is simple, the raw material cost is low, and it is easy to achieve mass production, which has important industrial prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Graph showing changes in energy storage density and charge-discharge efficiency of the thin films obtained in Example 1 of the present invention and Comparative Examples 1, 2, and 3 as a function of electric field;

[0027] Figure 2 Graph showing changes in energy storage density and charge-discharge efficiency of the thin films obtained in Example 2 of the present invention and Comparative Examples 1 and 4 as a function of electric field;

[0028] Figure 3 Graph showing changes in energy storage density and charge-discharge efficiency of the thin films obtained in Example 3 of the present invention and Comparative Examples 1 and 5 as a function of electric field;

[0029] Figure 4 Graph showing changes in energy storage density and charge-discharge efficiency of the thin films obtained in Example 4 of the present invention and Comparative Examples 1 and 6 as a function of electric field;

[0030] Figure 5 Graph showing changes in energy storage density and charge-discharge efficiency of the films obtained in Comparative Examples 7, 8, and 9 of the present invention as a function of electric field;

[0031] Figure 6 Graph showing the dielectric constant and dielectric loss of the films obtained in Examples 1, 2, 3, 4 of the present invention and Comparative Example 1 as a function of frequency;

[0032] Figure 7 This is a SEM image of the film obtained in Example 1 of the present invention;

[0033] Figure 8 This is an SEM image of the film obtained in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0034] The specific embodiments of the present invention are described below to facilitate understanding of the present invention by those skilled in the art. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, these changes are obvious, and all inventions and creations utilizing the concepts of the present invention are protected.

[0035] Example 1: The raw materials involved in this example include P (VDF-HFP) and ODA.

[0036] The preparation steps are as follows:

[0037] 1. Mix poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) and 4,4'-diaminodiphenyl ether (ODA) in a 99:1 mass ratio to create a 1 wt% solution. Weigh 0.198 g of poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) and 0.002 g of 4,4'-diaminodiphenyl ether (ODA) and add 10 ml of N,N-dimethylformamide (DMF) to form the solution.

[0038] 2. The above solution was dissolved under magnetic stirring at 60°C for 10 hours to allow the solute to fully dissolve in the solvent to obtain a P(VDF-HFP) / ODA mixed solution.

[0039] 3. Clean the glass slide to avoid dust contamination, then place the glass slide in a 70℃ oven for preheating for half an hour, then use a rubber-tipped dropper to draw 5ml of the above mixed solution and add it dropwise to the glass slide, let the solution flow naturally on the glass slide, and bake it in a 70℃ oven for 10 hours to evaporate the solvent.

[0040] 4. Place the glass sheet after the solvent has evaporated in a vacuum oven and adjust the temperature to perform a multi-stage high-temperature reaction. The temperature and time of each stage are: 120°C for ten hours, 240°C for one hour, and then naturally cool to room temperature to obtain a lightly cross-linked film.

[0041] 5. Soak the glass slide with the lightly cross-linked film in deionized water. After a period of time, the film will fall off the glass slide by itself. Wrap the fallen film with aluminum foil.

[0042] 6. Place the aluminum foil wrapped with the film in a vacuum oven and dry it at a high temperature of 120°C for 10 hours to obtain a P(VDF-HFP) / ODA (1 wt%) diamine monomer cross-linked modified fluorine-containing ferroelectric polymer film.

[0043] Implementation effect: The P(VDF-HFP) / ODA (1 wt%) diamine monomer cross-linked modified fluorine-containing ferroelectric polymer film prepared in this embodiment has a high dielectric constant, such as Figure 6 As shown, its dielectric constant is 8.53 at 1kHz; its energy storage density and charge and discharge efficiency are as follows Figure 1 As shown in Figure 2, the breakdown electric field strength is increased to 550MV / m and the discharge energy density is 11.56J / cm 3 The charge and discharge efficiency is 44.5%. The SEM photo of the brittle fracture surface of the fluorine-containing ferroelectric polymer film is shown in the figure below. Figure 7 shown.

[0044] Example 2: The raw materials involved in this example include P (VDF-HFP) and HFBAPP.

[0045] The preparation steps are as follows:

[0046] 1. Mix poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) and 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (HFBAPP) in a 95:5 mass ratio to create a 5 wt% solution. Weigh 0.19 g of poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) and 0.01 g of 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (HFBAPP)) and add 10 ml of DMF to form the solution.

[0047] 2. The above solution was dissolved and dispersed at 60°C with magnetic stirring for 10 hours to allow the solute to be fully and evenly dissolved in the solvent.

[0048] 3. Clean the glass slide to avoid dust contamination, then place the glass slide in a 70℃ oven for preheating for half an hour, then use a rubber-tipped dropper to draw 5ml of the above mixed solution and add it dropwise to the glass slide, let the solution flow naturally on the glass slide, and bake it in a 70℃ oven for 10 hours to evaporate the solvent.

[0049] 4. Place the glass sheet after the solvent has evaporated in a vacuum oven and adjust the temperature to perform a multi-stage high-temperature reaction. The temperature and time of each stage are: 120°C for ten hours, 240°C for one hour, and then naturally cool to room temperature to obtain a cross-linked film.

[0050] 5. Soak the glass slide with the lightly cross-linked film in deionized water. After a period of time, the film will fall off the glass slide by itself. Wrap the fallen film with aluminum foil.

[0051] 6. Place the aluminum foil wrapped with the film in a vacuum oven and dry it at a high temperature of 120°C for 10 hours to obtain a P(VDF-HFP) / HFBAPP (5wt%) diamine monomer cross-linked modified fluorine-containing ferroelectric polymer film.

[0052] Implementation effect: The P(VDF-HFP) / HFBAPP (5wt%) diamine monomer cross-linked modified fluorine-containing ferroelectric polymer film prepared in this embodiment has a high dielectric constant, such as Figure 6 As shown in Figure 2, its dielectric constant is 7.86 at 1kHz; its energy storage density and charge and discharge efficiency are shown in Figure 2. Figure 2 As shown in Figure 2, the breakdown electric field strength is increased to 500MV / m and the discharge energy density is 9.77J / cm 3 , the charge and discharge efficiency is 41.7%.

[0053] Example 3: The raw materials involved in this example include P (VDF-HFP) and BAPS.

[0054] The preparation steps are as follows:

[0055] 1. Mix poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) and bis[4-(4-aminophenoxy)phenyl]sulfone (BAPS) in a 95:5 mass ratio to prepare a 5 wt% solution. Weigh 0.19 g of poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) and 0.01 g of bis[4-(4-aminophenoxy)phenyl]sulfone (BAPS) and add 10 ml of DMF to prepare the solution.

[0056] 2. The above solution was dissolved and dispersed at 60°C with magnetic stirring for 10 hours to allow the solute to be fully and evenly dissolved in the solvent.

[0057] 3. Clean the glass slide to avoid dust contamination, then place the glass slide in a 70℃ oven for preheating for half an hour, then use a rubber-tipped dropper to draw 5ml of the above mixed solution and add it dropwise to the glass slide, let the solution flow naturally on the glass slide, and bake it in a 70℃ oven for 10 hours to evaporate the solvent.

[0058] 4. Place the glass sheet after the solvent has evaporated in a vacuum oven and adjust the temperature to perform a multi-stage high-temperature reaction. The temperature and time of each stage are: 120°C for ten hours, 240°C for one hour, and then naturally cool to room temperature to obtain a cross-linked film.

[0059] 5. Soak the glass slide with the lightly cross-linked film in deionized water. After a period of time, the film will fall off the glass slide by itself. Wrap the fallen film with aluminum foil.

[0060] 6. Place the aluminum foil wrapped with the film in a vacuum oven and dry it at a high temperature of 120°C for 10 hours to obtain a fluorine-containing ferroelectric polymer film with a lightly cross-linked network of P(VDF-HFP) / BAPS (5wt%).

[0061] Implementation effect: The P(VDF-HFP) / BAPS (5wt%) diamine monomer cross-linked modified fluorine-containing ferroelectric polymer film prepared in this embodiment has a high dielectric constant, such as Figure 6 As shown in Figure 2, its dielectric constant is 8.31 at 1kHz; its energy storage density and charge and discharge efficiency are shown in Figure 2. Figure 3 As shown in Figure 2, the breakdown electric field strength is increased to 350MV / m and the discharge energy density is 4.11J / cm 3 , the charge and discharge efficiency is 49.8%.

[0062] Example 4: The raw materials involved in this example include P (VDF-HFP) and BTMB.

[0063] The preparation steps are as follows:

[0064] 1. Mix poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) and (BTMB) in a 95:5 mass ratio to create a 5 wt% solution. Weigh 0.19 g of poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) and 0.01 g of (BTMB) and add 10 ml of DMF to create the solution.

[0065] 2. The above solution was dissolved and dispersed at 60°C with magnetic stirring for 10 hours to allow the solute to be fully and evenly dissolved in the solvent.

[0066] 3. Clean the glass slide to avoid dust contamination, then place the glass slide in a 70℃ oven for preheating for half an hour, then use a rubber-tipped dropper to draw 5ml of the above mixed solution and add it dropwise to the glass slide, let the solution flow naturally on the glass slide, and bake it in a 70℃ oven for 10 hours to evaporate the solvent.

[0067] 4. Place the glass sheet after the solvent has evaporated in a vacuum oven and adjust the temperature to perform a multi-stage high-temperature reaction. The temperature and time of each stage are: 120°C for ten hours, 240°C for one hour, and then naturally cool to room temperature to obtain a cross-linked film.

[0068] 5. Soak the glass slide with the lightly cross-linked film in deionized water. After a period of time, the film will fall off the glass slide by itself. Wrap the fallen film with aluminum foil.

[0069] 6. Place the aluminum foil wrapped with the film in a vacuum oven and dry it at a high temperature of 120°C for 10 hours to obtain a P(VDF-HFP) / BTMB (5wt%) diamine monomer cross-linked modified fluorine-containing ferroelectric polymer film.

[0070] Implementation effect: The P(VDF-HFP) / BTMB (5wt%) diamine monomer cross-linked modified fluorine-containing ferroelectric polymer film prepared in this embodiment has a high dielectric constant, such as Figure 6 As shown, its dielectric constant is 8.85 at 1kHz; its energy storage density and charge and discharge efficiency are as follows Figure 4 As shown in Figure 2, the breakdown electric field strength is increased to 450MV / m and the discharge energy density is 7.71J / cm 3 , the charge and discharge efficiency is 41.3%.

[0071] Comparative Example 1: The raw materials involved in this comparative example include P(VDF-HFP).

[0072] The preparation steps are as follows:

[0073] 1. Weigh 0.2 g of poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) and add 10 ml of DMF to prepare a solution.

[0074] 2. The above solution was dissolved and dispersed at 60°C with magnetic stirring for 10 hours to allow the solute to be fully and evenly dissolved in the solvent.

[0075] 3. Clean the glass slide to avoid dust contamination, then place the glass slide in a 70℃ oven for preheating for half an hour, then use a rubber-tipped dropper to draw 5ml of the above mixed solution and add it dropwise to the glass slide, let the solution flow naturally on the glass slide, and bake it in a 70℃ oven for 10 hours to evaporate the solvent.

[0076] 4. Place the glass sheet after the solvent has evaporated in a vacuum oven and adjust the temperature to perform multiple high-temperature reactions. The temperature and time of each stage are: 120°C for ten hours, 240°C for one hour, and then naturally cool to room temperature to obtain a film.

[0077] 5. Soak the glass slide with the film in deionized water. After a period of time, the film will fall off the glass slide by itself. Wrap the fallen film with aluminum foil.

[0078] 6. Place the aluminum foil wrapped with the film in a vacuum oven and dry it at 120°C for 10 hours to obtain the P(VDF-HFP) polymer dielectric film.

[0079] Comparative effect: The energy storage density and charge-discharge efficiency of the P(VDF-HFP) fluorine-containing ferroelectric polymer film prepared in this comparative example are as follows: Figure 1 As shown, it has low energy storage density and energy storage efficiency. When the electric field strength is 400MV / m, the charge and discharge efficiency is only 37.33%, and the discharge energy density is 6.02J / cm 3 The SEM image of the brittle fracture surface of the fluorine-containing ferroelectric polymer film is as follows: Figure 8 shown.

[0080] Comparative Example 2: The raw materials involved in this comparative example include P (VDF-HFP) and ODA.

[0081] The preparation steps are as follows:

[0082] 1. Mix poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) and 4,4'-diaminodiphenyl ether (ODA) in a mass ratio of 99.75:0.25 to create a 0.25 wt% solution. Weigh 0.1995 g of poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) and 0.0005 g of 4,4'-diaminodiphenyl ether (ODA) and add 10 ml of DMF to form the solution.

[0083] 2. The above solution was dissolved and dispersed at 60°C with magnetic stirring for 10 hours to allow the solute to be fully and evenly dissolved in the solvent.

[0084] 3. Clean the glass slide to avoid dust contamination, then place the glass slide in a 70℃ oven for preheating for half an hour, then use a rubber-tipped dropper to draw 5ml of the above mixed solution and add it dropwise to the glass slide, let the solution flow naturally on the glass slide, and bake it in a 70℃ oven for 10 hours to evaporate the solvent.

[0085] 4. Place the glass sheet after the solvent has evaporated in a vacuum oven and adjust the temperature to perform a multi-stage high-temperature reaction. The temperature and time of each stage are: 120°C for ten hours, 240°C for one hour, and then naturally cool to room temperature to obtain a cross-linked film.

[0086] 5. Soak the glass slide with the lightly cross-linked film in deionized water. After a period of time, the film will fall off the glass slide by itself. Wrap the fallen film with aluminum foil.

[0087] 6. Place the aluminum foil wrapped with the film in a vacuum oven and dry it at a high temperature of 120°C for 10 hours to obtain a P(VDF-HFP) / ODA (0.25wt%) diamine monomer cross-linked modified fluorine-containing ferroelectric polymer film.

[0088] Comparative effect: The energy storage density and charge-discharge efficiency of the P(VDF-HFP) / ODA (0.25wt%) diamine monomer cross-linked modified fluorine-containing ferroelectric polymer film prepared in this comparative example are as follows: Figure 1 As shown, it has low energy storage density and energy storage efficiency. When the electric field strength is 500MV / m, the charge and discharge efficiency is 47.97%, and the discharge energy density is 9.1J / cm 3 .

[0089] Comparative Example 3: The raw materials involved in this comparative example include P (VDF-HFP) and ODA.

[0090] The preparation steps are as follows:

[0091] 1. Mix poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) and 4,4'-diaminodiphenyl ether (ODA) in a 90:10 mass ratio to create a 10 wt% solution. Weigh 0.180 g of poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) and 0.020 g of 4,4'-diaminodiphenyl ether (ODA) and add 10 ml of DMF to create the solution.

[0092] 2. The above solution was dissolved and dispersed at 60°C with magnetic stirring for 10 hours to allow the solute to be fully and evenly dissolved in the solvent.

[0093] 3. Clean the glass slide to avoid dust contamination, then place the glass slide in a 70℃ oven for preheating for half an hour, then use a rubber-tipped dropper to draw 5ml of the above mixed solution and add it dropwise to the glass slide, let the solution flow naturally on the glass slide, and bake it in a 70℃ oven for 10 hours to evaporate the solvent.

[0094] 4. Place the glass sheet after the solvent has evaporated in a vacuum oven and adjust the temperature to perform a multi-stage high-temperature reaction. The temperature and time of each stage are: 120°C for ten hours, 240°C for one hour, and then naturally cool to room temperature to obtain a cross-linked film.

[0095] 5. Soak the glass slide with the lightly cross-linked film in deionized water. After a period of time, the film will fall off the glass slide by itself. Wrap the fallen film with aluminum foil.

[0096] 6. Place the aluminum foil wrapped with the film in a vacuum oven and dry it at a high temperature of 120°C for 10 hours to obtain a P(VDF-HFP) / ODA (10 wt%) diamine monomer cross-linked modified fluorine-containing ferroelectric polymer film.

[0097] Comparative effect: The energy storage density and charge-discharge efficiency of the P(VDF-HFP) / ODA (10 wt%) diamine monomer cross-linked modified fluorine-containing ferroelectric polymer film prepared in this comparative example are as follows: Figure 1 As shown, it has low energy storage density and energy storage efficiency. When the electric field strength is 500MV / m, the charge and discharge efficiency is 43.12%, and the discharge energy density is 8.3J / cm 3 .

[0098] Comparative Example 4: The raw materials involved in this comparative example include P(VDF-HFP) and HFBAPP.

[0099] The preparation steps are as follows:

[0100] 1. Mix poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) and 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (HFBAPP) in a 90:10 mass ratio to prepare a 10 wt% solution. Weigh 0.18 g of poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) and 0.02 g of 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (HFBAPP) and add 10 ml of DMF to prepare the solution.

[0101] 2. The above solution was dissolved and dispersed at 60°C with magnetic stirring for 10 hours to allow the solute to be fully and evenly dissolved in the solvent.

[0102] 3. Clean the glass slide to avoid dust contamination, then place the glass slide in a 70℃ oven for preheating for half an hour, then use a rubber-tipped dropper to draw 5ml of the above mixed solution and add it dropwise to the glass slide, let the solution flow naturally on the glass slide, and bake it in a 70℃ oven for 10 hours to evaporate the solvent.

[0103] 4. Place the glass sheet after the solvent has evaporated in a vacuum oven and adjust the temperature to perform a multi-stage high-temperature reaction. The temperature and time of each stage are: 120°C for ten hours, 240°C for one hour, and then naturally cool to room temperature to obtain a cross-linked film.

[0104] 5. Soak the glass slide with the lightly cross-linked film in deionized water. After a period of time, the film will fall off the glass slide by itself. Wrap the fallen film with aluminum foil.

[0105] 6. Place the aluminum foil wrapped with the film in a vacuum oven and dry it at a high temperature of 120°C for 10 hours to obtain a P(VDF-HFP) / HFBAPP (10 wt%) diamine monomer cross-linked modified fluorine-containing ferroelectric polymer film.

[0106] Comparative effect: The energy storage density and charge-discharge efficiency of the P(VDF-HFP) / HFBAPP (10wt%) diamine monomer cross-linked modified fluorine-containing ferroelectric polymer film prepared in this comparative example are as follows: Figure 2 As shown, it has low energy storage density and energy storage efficiency. When the electric field strength is 500MV / m, the charge and discharge efficiency is 36.57%, and the discharge energy density is 8.48J / cm 3 .

[0107] Comparative Example 5: The raw materials involved in this comparative example include P (VDF-HFP) and BAPS.

[0108] The preparation steps are as follows:

[0109] 1. Mix poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) and bis[4-(4-aminophenoxy)phenyl]sulfone (BAPS) in a 90:10 mass ratio to prepare a 10 wt% solution. Weigh 0.18 g of poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) and 0.02 g of bis[4-(4-aminophenoxy)phenyl]sulfone (BAPS) and add 10 ml of DMF to prepare the solution.

[0110] 2. The above solution was dissolved and dispersed at 60°C with magnetic stirring for 10 hours to allow the solute to be fully and evenly dissolved in the solvent.

[0111] 3. Clean the glass slide to avoid dust contamination, then place the glass slide in a 70℃ oven for preheating for half an hour, then use a rubber-tipped dropper to draw 5ml of the above mixed solution and add it dropwise to the glass slide, let the solution flow naturally on the glass slide, and bake it in a 70℃ oven for 10 hours to evaporate the solvent.

[0112] 4. Place the glass sheet after the solvent has evaporated in a vacuum oven and adjust the temperature to perform a multi-stage high-temperature reaction. The temperature and time of each stage are: 120°C for ten hours, 240°C for one hour, and then naturally cool to room temperature to obtain a cross-linked film.

[0113] 5. Soak the glass slide with the lightly cross-linked film in deionized water. After a period of time, the film will fall off the glass slide by itself. Wrap the fallen film with aluminum foil.

[0114] 6. Place the aluminum foil wrapped with the film in a vacuum oven and dry it at a high temperature of 120°C for 10 hours to obtain a P(VDF-HFP) / BAPS (10 wt%) diamine monomer cross-linked modified fluorine-containing ferroelectric polymer film.

[0115] Comparative effect: The energy storage density and charge-discharge efficiency of the P(VDF-HFP) / BAPS (10wt%) diamine monomer cross-linked modified fluorine-containing ferroelectric polymer film prepared in this comparative example are as follows: Figure 3 As shown, it has low energy storage density and energy storage efficiency. When the electric field strength is 350MV / m, the charge and discharge efficiency is 45.06%, and the discharge energy density is 4.3J / cm 3 .

[0116] Comparative Example 6: The raw materials involved in this comparative example include P(VDF-HFP) and BTMB.

[0117] The preparation steps are as follows:

[0118] 1. Mix poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) and BTMB in a 90:10 mass ratio to create a 10 wt% solution. For example, weigh 0.18 g of poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)), 0.02 g of BTMB, and add 10 ml of DMF to create the solution.

[0119] 2. The above solution was dissolved and dispersed at 60°C with magnetic stirring for 10 hours to allow the solute to be fully and evenly dissolved in the solvent.

[0120] 3. Clean the glass slide to avoid dust contamination, then place the glass slide in a 70℃ oven for preheating for half an hour, then use a rubber-tipped dropper to draw 5ml of the above mixed solution and add it dropwise to the glass slide, let the solution flow naturally on the glass slide, and bake it in a 70℃ oven for 10 hours to evaporate the solvent.

[0121] 4. Place the glass sheet after the solvent has evaporated in a vacuum oven and adjust the temperature to perform a multi-stage high-temperature reaction. The temperature and time of each stage are: 120°C for ten hours, 240°C for one hour, and then naturally cool to room temperature to obtain a cross-linked film.

[0122] 5. Soak the glass slide with the lightly cross-linked film in deionized water. After a period of time, the film will fall off the glass slide by itself. Wrap the fallen film with aluminum foil.

[0123] 6. Place the aluminum foil wrapped with the film in a vacuum oven and dry it at a high temperature of 120°C for 10 hours to obtain a fluorine-containing ferroelectric polymer film with a slightly cross-linked network of P(VDF-HFP) / BTMB (10wt%).

[0124] Comparative effect: The energy storage density and charge-discharge efficiency of the P(VDF-HFP) / BTMB (10wt%) diamine monomer cross-linked modified fluorine-containing ferroelectric polymer film prepared in this comparative example are as follows: Figure 4 As shown, it has low energy storage density and energy storage efficiency. When the electric field strength is 350MV / m, the charge and discharge efficiency is 41.69%, and the discharge energy density is 4.46J / cm 3 .

[0125] Comparative Example 7: The raw materials involved in this comparative example include P(VDF-TrFE-CFE) and ODA.

[0126] The preparation steps are as follows:

[0127] 1. Mix P(VDF-TrFE-CFE) and ODA in a 95:5 mass ratio to create a 5 wt% solution. For example, weigh 0.19 g of P(VDF-TrFE-CFE), 0.01 g of ODA, and add 10 ml of DMF to create the solution.

[0128] 2. The above solution was dissolved and dispersed at 60°C with magnetic stirring for 10 hours to allow the solute to be fully and evenly dissolved in the solvent.

[0129] 3. Clean the glass slide to avoid dust contamination, then place the glass slide in a 70℃ oven for preheating for half an hour, then use a rubber-tipped dropper to draw 5ml of the above mixed solution and add it dropwise to the glass slide, let the solution flow naturally on the glass slide, and bake it in a 70℃ oven for 10 hours to evaporate the solvent.

[0130] 4. Place the glass sheet after the solvent has evaporated in a vacuum oven and adjust the temperature to perform a multi-stage high-temperature reaction. The temperature and time of each stage are: 120°C for ten hours, 240°C for one hour, and then naturally cool to room temperature to obtain a cross-linked film.

[0131] 5. Soak the glass slide with the lightly cross-linked film in deionized water. After a period of time, the film will fall off the glass slide by itself. Wrap the fallen film with aluminum foil.

[0132] 6. Place the aluminum foil wrapped with the film in a vacuum oven and dry it at 120°C for 10 hours to obtain a fluorine-containing ferroelectric polymer film with a slightly cross-linked network of P(VDF-TrFE-CFE) / ODA (5wt%).

[0133] Comparative effect: The energy storage density and charge-discharge efficiency of the P(VDF-TrFE-CFE) / ODA (5wt%) diamine monomer cross-linked modified fluorine-containing ferroelectric polymer film prepared in this comparative example are as follows: Figure 5 As shown, it has low energy storage density and energy storage efficiency. When the electric field strength is 250MV / m, the charge and discharge efficiency is 20.44%, and the discharge energy density is 2.54J / cm 3 .

[0134] Comparative Example 8: The raw materials involved in this comparative example include P(VDF-TrFE-CFE) and HFBAPP.

[0135] The preparation steps are as follows:

[0136] 1. Mix P(VDF-TrFE-CFE) and HFBAPP in a 95:5 mass ratio to create a 5 wt% solution. For example, weigh 0.19 g of P(VDF-TrFE-CFE) and 0.01 g of HFBAPP and add 10 ml of DMF to create the solution.

[0137] 2. The above solution was dissolved and dispersed at 60°C with magnetic stirring for 10 hours to allow the solute to be fully and evenly dissolved in the solvent.

[0138] 3. Clean the glass slide to avoid dust contamination, then place the glass slide in a 70℃ oven for preheating for half an hour, then use a rubber-tipped dropper to draw 5ml of the above mixed solution and add it dropwise to the glass slide, let the solution flow naturally on the glass slide, and bake it in a 70℃ oven for 10 hours to evaporate the solvent.

[0139] 4. Place the glass sheet after the solvent has evaporated in a vacuum oven and adjust the temperature to perform a multi-stage high-temperature reaction. The temperature and time of each stage are: 120°C for ten hours, 240°C for one hour, and then naturally cool to room temperature to obtain a cross-linked film.

[0140] 5. Soak the glass slide with the lightly cross-linked film in deionized water. After a period of time, the film will fall off the glass slide by itself. Wrap the fallen film with aluminum foil.

[0141] 6. Place the aluminum foil wrapped with the film in a vacuum oven and dry it at 120°C for 10 hours to obtain a fluorine-containing ferroelectric polymer film with a slightly cross-linked network of P(VDF-TrFE-CFE) / HFBAPP (5wt%).

[0142] Comparative effect: The energy storage density and charge-discharge efficiency of the P(VDF-TrFE-CFE) / HFBAPP (5wt%) diamine monomer cross-linked modified fluorine-containing ferroelectric polymer film prepared in this comparative example are as follows: Figure 5 As shown, it has low energy storage density and energy storage efficiency. When the electric field strength is 350MV / m, the charge and discharge efficiency is 22.2%, and the discharge energy density is 4.43J / cm 3 .

[0143] Comparative Example 9: The raw materials involved in this comparative example include P(VDF-TrFE-CFE) and BAPS.

[0144] The preparation steps are as follows:

[0145] 1. Mix P(VDF-TrFE-CFE) and BAPS in a 95:5 mass ratio to create a 5 wt% solution. For example, weigh 0.19 g of P(VDF-TrFE-CFE) and 0.01 g of BAPS and add 10 ml of DMF to create the solution.

[0146] 2. The above solution was dissolved and dispersed at 60°C with magnetic stirring for 10 hours to allow the solute to be fully and evenly dissolved in the solvent.

[0147] 3. Clean the glass slide to avoid dust contamination, then place the glass slide in a 70℃ oven for preheating for half an hour, then use a rubber-tipped dropper to draw 5ml of the above mixed solution and add it dropwise to the glass slide, let the solution flow naturally on the glass slide, and bake it in a 70℃ oven for 10 hours to evaporate the solvent.

[0148] 4. Place the glass sheet after the solvent has evaporated in a vacuum oven and adjust the temperature to perform a multi-stage high-temperature reaction. The temperature and time of each stage are: 120°C for ten hours, 240°C for one hour, and then naturally cool to room temperature to obtain a cross-linked film.

[0149] 5. Soak the glass slide with the lightly cross-linked film in deionized water. After a period of time, the film will fall off the glass slide by itself. Wrap the fallen film with aluminum foil.

[0150] 6. Place the aluminum foil wrapped with the film in a vacuum oven and dry it at a high temperature of 120°C for 10 hours to obtain a fluorine-containing ferroelectric polymer film with a slightly cross-linked network of P(VDF-TrFE-CFE) / BAPS (5wt%).

[0151] Comparative effect: The energy storage density and charge-discharge efficiency of the P(VDF-TrFE-CFE) / BAPS (5wt%) diamine monomer cross-linked modified fluorine-containing ferroelectric polymer film prepared in this comparative example are as follows: Figure 5 As shown, it has low energy storage density and energy storage efficiency. When the electric field strength is 300MV / m, the charge and discharge efficiency is 19.1%, and the discharge energy density is 3.68J / cm 3 .

[0152] In summary, the thin film prepared by the present invention meets application requirements such as increased dielectric constant, reduced dielectric loss, reduced leakage current, and increased breakdown field strength under high-field conditions. The addition of the diamine monomer increases the crystallinity and β-phase content of the semi-crystalline thermoplastic fluorine-containing ferroelectric polymer serving as the matrix.

[0153] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

[0154] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A diamine monomer cross-linked modified fluorine-containing ferroelectric polymer, characterized in that: It is used as a film capacitor; its components include a semi-crystalline thermoplastic fluorine-containing ferroelectric polymer and a diamine cross-linking agent; the mass fraction of the diamine cross-linking agent relative to the total mass of the fluorine-containing ferroelectric polymer and the diamine cross-linking agent is 0.5% to 5%; The semicrystalline thermoplastic fluorine-containing ferroelectric polymer is poly(vinylidene fluoride-hexafluoropropylene); The diamine crosslinking agent includes at least one of diaminodiphenylmethane, diaminodiphenyl sulfone, 4,4ʹ-diaminodiphenyl ether, bis[4-(4-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(3-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 9,9-bis(3-fluoro-4-aminophenyl)fluorene, and 2,2'-bis(trifluoromethyl)diaminobiphenyl.

2. The method for preparing a diamine monomer cross-linked modified fluorine-containing ferroelectric polymer according to claim 1, characterized in that: The following steps are involved: First, a semi-crystalline thermoplastic fluorine-containing ferroelectric polymer was blended with a diamine monomer and prepared into an uncrosslinked film by a solution casting method; Then, the film is treated at high temperature in a vacuum environment to induce a cross-linking reaction between the diamine monomer and the fluorine-containing ferroelectric polymer to form a fluorine-containing ferroelectric polymer film with a lightly cross-linked network.

3. The method for preparing a diamine monomer cross-linked modified fluorine-containing ferroelectric polymer according to claim 2, characterized in that: It includes the following sub-steps: S1. The semi-crystalline thermoplastic fluorine-containing ferroelectric polymer and a diamine crosslinker are dissolved in an organic solvent and heated to dissolve to obtain a slurry composition having a solid content of 0.1 wt% -20 wt%; S2. The slurry is formed into a film by solution casting; specifically, the slurry is evenly coated on a glass substrate and baked at 60-90 ° C to evaporate the solvent as much as possible to obtain an uncrosslinked film; S3. After the solvent is evaporated, the glass substrate is subjected to a cross-linking reaction at multiple temperature ranges between 100°C and 250°C to obtain a cross-linked film; S4. Place the glass substrate with the cross-linked film in deionized water to peel off the film, and dry the peeled film at high temperature to obtain a diamine monomer cross-linked modified fluorine-containing ferroelectric polymer film.

4. The method for preparing a diamine monomer cross-linked modified fluorine-containing ferroelectric polymer according to claim 3, characterized in that: In step S1, the solid content of the slurry is 1 wt %-2 wt %.

5. The method for preparing a diamine monomer cross-linked modified fluorine-containing ferroelectric polymer according to claim 3, characterized in that: In step S3, the cross-linking process is 120°C × 10h + 240°C × 1h.

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