Flexible polymer composite membrane with high dielectric property, preparation method of flexible polymer composite membrane and application of flexible polymer composite membrane in tumor treatment field patch

Abstract

The invention discloses a high-dielectric-property flexible polymer composite film, a preparation method thereof and application of the high-dielectric-property flexible polymer composite film in a tumor treatment field patch, and relates to the technical field of energy storage capacitors. Piezoelectric ceramic particles with the chemical formula of (BixBaySr1-1.5 x-y) (TizZr1-z) O3 (x is more than or equal to 0 and less than or equal to 0.2, y is more than or equal to 0 and less than or equal to 1-1.5 x, and z is more than or equal to 0 and less than or equal to 1) are modified by a coupling agent to obtain the coupling agent modified ceramic filler; then mixing the PVDF-based copolymer, PMMA (polymethyl methacrylate) and TPU (thermoplastic polyurethane) to obtain a complex-phase organic matter matrix; the flexible polymer composite membrane is prepared from the coupling agent modified ceramic filler and the multiphase organic matter matrix. The flexible polymer composite film has good flexibility, high dielectric constant and low dielectric loss, can be attached to the curved surface of a human body, and reduces the working voltage of an electrode.

Description

Technical Field

[0001] This invention relates to the field of energy storage capacitor technology, and in particular to a flexible polymer composite film with high dielectric properties, its preparation method, and its application in tumor treatment field patches. Background Technology

[0002] In recent years, tumor electric field therapy (TTF) technology has provided an innovative approach to cancer treatment by inhibiting cancer cell division through high-frequency alternating electric fields. Electrode patches are a key component, and their dielectric properties directly affect treatment efficacy and patient comfort. However, traditional electrode patches use ceramic dielectric layers to achieve high dielectric constants, but their rigid structure makes it difficult for the patches to adapt to the dynamic deformation of human skin. In frequently moving areas such as the chest or abdomen, ceramic electrodes are prone to poor fit and electric field leakage, reducing treatment efficiency. Furthermore, the rigid edges may compress the skin, causing inflammation or discomfort, limiting the feasibility of long-term wear.

[0003] Traditional polymer-based materials possess good flexibility and can be used as patch materials for tumor therapy. For example, pure PVDF (polyvinylidene fluoride), while exhibiting good flexibility, suffers from drawbacks such as a low dielectric constant (εr < 10), high dielectric loss (> 0.1), and low breakdown electric field (< 400 kV / mm). These drawbacks can lead to insufficient therapeutic efficacy, increased energy consumption and heat accumulation risks, and potential patient discomfort. Therefore, developing novel dielectric materials that combine high dielectric properties with excellent mechanical flexibility is crucial for improving the efficiency of TTF therapy and enhancing patient comfort.

[0004] Current research has explored adding ceramic fillers to polymer-based materials to improve dielectric properties, but several challenges remain in practical applications. First, the incompatibility between nano-ceramic fillers and the polymer matrix can lead to uneven filler dispersion and even agglomeration, resulting in localized differences in dielectric strength and even material breakdown. Second, the filler content also affects the flexibility and dielectric properties of the composite material. Excessive filler content, while providing good dielectric properties, compromises flexibility; conversely, insufficient filler content results in poor dielectric properties, impacting therapeutic efficacy. Furthermore, interfacial defects between the filler and the polymer matrix can cause stress concentration, significantly reducing material durability. Even worse, single polymer matrices (such as PVDF-based copolymers) exhibit high dielectric losses at high frequencies, leading to decreased energy conversion efficiency.

[0005] In the prior art, CN115362567A discloses a lead-free three-component piezoelectric polymer composite material, comprising a polymer matrix and a piezoelectric ceramic filler embedded in the polymer matrix. The polymer matrix comprises at least two polymers. The polymer matrix may include thermoplastic polymers, such as vinylidene fluoride (PVDF) and polymethyl methacrylate (PMMA). Specifically, barium titanate is used as the piezoelectric ceramic with a barium titanate loading of 40%, and PVDF-TrFE-CFE is used as the first polymer, with PPO, PVDF, or PC as the second polymer to obtain the composite material. In this composite material, the mass percentage of barium titanate is 40%-60%. Such a high doping amount of piezoelectric ceramic would compromise the material's flexibility, making it difficult to adapt to the dynamic deformation of human skin when used as a field patch for tumor treatment.

[0006] Therefore, there is an urgent need to develop a novel material that optimizes dielectric properties through the combination of multiphase organic compounds and enhances stability through advanced dispersion processes, in order to meet the stringent requirements of tumor electric field therapy for dielectric materials. Summary of the Invention

[0007] In view of the above-mentioned prior art, the purpose of this invention is to provide a flexible polymer composite film with high dielectric properties, its preparation method, and its application in tumor therapeutic field patches. This invention uses a coupling agent with the chemical formula (Bi) x Ba y Sr 1-1.5x-y (Ti) z Zr 1-z After modifying piezoelectric ceramic particles with O3 (0≤x≤0.2, 0≤y≤1-1.5x, 0≤z≤1), coupling agent-modified ceramic fillers are obtained. Then, PVDF-based copolymers, PMMA, and TPU are mixed to prepare a multiphase organic matrix. A flexible polymer composite film is obtained using the coupling agent-modified ceramic filler and the multiphase organic matrix. This flexible polymer composite film not only possesses good flexibility but also high dielectric constant and low dielectric loss, allowing it to conform to the curved surfaces of the human body and reduce electrode operating voltage, thereby improving its application effect as a field patch for tumor treatment. Furthermore, the addition of PMMA and TPU to the PVDF-based copolymer exhibits a synergistic effect in improving the dielectric properties and flexibility of the flexible polymer composite film.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a flexible polymer composite membrane prepared from a coupling agent modified ceramic filler and a multiphase organic matrix in a mass ratio of (20-35):(65-80);

[0010] The multiphase organic matrix is ​​composed of PVDF-based copolymer, polymethyl methacrylate (PMMA), and thermoplastic polyurethane (TPU) in a mass ratio of (60-98.9):(1-20):(0.1-20);

[0011] The coupling agent modified ceramic filler was prepared by the following method:

[0012] Piezoelectric ceramic particles are added to an organic solvent, followed by the addition of a coupling agent and stirring, to obtain a coupling agent-modified ceramic filler; the chemical formula of the piezoelectric ceramic particles is (Bi... x Ba y Sr 1-1.5x-y (Ti) z Zr 1-z O3, where 0≤x≤0.2, 0≤y≤1-1.5x, and 0≤z≤1.

[0013] Preferably, the coupling agent is one or more of zirconate coupling agents, aluminate coupling agents, titanate coupling agents, Tween-20, and Tween-60; the concentration of the coupling agent used is 1-5 wt%.

[0014] Preferably, the organic solvent is ethanol or isopropanol, and the mass fraction of the organic solvent is 98%.

[0015] Preferably, the piezoelectric ceramic particles have a particle size of 20-400 nm.

[0016] Preferably, the ratio of piezoelectric ceramic particles, coupling agent solution, and organic solvent is 1g:(0.01-0.05)mL:20mL.

[0017] Preferably, the stirring time is 10-15 hours.

[0018] Preferably, the PVDF-based copolymer is at least one of PVDF, PVDF-HFP, PVDF-TrEE, P(VDF-TrFE-CFE), and P(VDF-TrFE-CFE-CTFE).

[0019] Preferably, the mixing temperature is 40-50℃ and the mixing time is 1.5-2.5h.

[0020] A second aspect of the present invention provides a method for preparing the above-mentioned flexible polymer composite film, comprising the following steps:

[0021] (1) The coupling agent modified ceramic filler is dispersed in an organic solvent, and after ultrasonic treatment and stirring, a dispersion of the coupling agent modified ceramic filler is obtained; the multiphase organic matrix is ​​added to the organic solvent to obtain a multiphase organic matrix solution.

[0022] (2) Add the coupling agent modified ceramic filler dispersion to the multiphase organic matrix solution and stir to obtain a composite slurry; coat the composite slurry onto the substrate and dry to obtain a flexible polymer composite film.

[0023] Preferably, in step (1), the organic solvent is dimethylacetamide (DMAC) and / or tetrahydrofuran (THF).

[0024] Furthermore, when the organic solvent is dimethylacetamide (DMAC) and tetrahydrofuran (THF), the volume ratio of the two is 1:1.

[0025] Preferably, in step (1), the ratio of the coupling agent-modified ceramic filler to the organic solvent is 1 g: (8-12) mL.

[0026] Preferably, in step (1), the ratio of the multiphase organic matrix to the organic solvent is (3-5) g: 10 mL.

[0027] Preferably, in step (1), the ultrasonic power is 250-350W, the ultrasonic treatment time is 25-35min, and the stirring time is 5.5-6.5h.

[0028] Preferably, in step (2), the drying temperature is 65-75℃ and the drying time is 12h.

[0029] Preferably, in step (2), the thickness of the flexible polymer composite film is 20-50 μm.

[0030] A third aspect of the present invention provides the application of the above-described flexible polymer composite film in the preparation of tumor therapeutic field patches.

[0031] The beneficial effects of this invention are:

[0032] 1. This invention uses a coupling agent to couple the chemical formula (Bi) x Ba y Sr 1-1.5x-y (Ti) z Zr 1-zAfter modifying piezoelectric ceramic particles of O3 (0≤x≤0.2, 0≤y≤1-1.5x, 0≤z≤1), coupling agent-modified ceramic fillers are obtained. Then, PVDF-based copolymers, PMMA, and TPU are mixed to prepare a multiphase organic matrix. A flexible polymer composite film is obtained using the coupling agent-modified ceramic filler and the multiphase organic matrix. This flexible polymer composite film not only possesses good flexibility but also high dielectric constant and low dielectric loss, allowing it to conform to the curved surfaces of the human body and reduce electrode operating voltage, thereby improving its application effect as a field patch for tumor treatment. Specifically, the dielectric constant of the flexible polymer composite film obtained in this invention reaches over 20 at 1MHz, and the dielectric loss is less than 0.2. At frequencies of 100-1MHz, electrode patches using this flexible polymer composite film can reduce the applied voltage, reducing energy consumption and the risk of heat accumulation.

[0033] 2. This invention incorporates PMMA and TPU compounded into a PVDF-based copolymer, resulting in a synergistic effect in improving the dielectric properties and flexibility of the flexible polymer composite film. Simultaneously, this invention uses a coupling agent to... x Ba y Sr 1-1.5x-y (Ti) z Zr 1-z Surface modification of piezoelectric ceramics with O3 (0≤x≤0.2, 0≤y≤1-1.5x, 0≤z≤1) and coupling agents can improve the compatibility between the piezoelectric ceramics and the multiphase organic matrix, increase the dispersion of the piezoelectric ceramics in the multiphase organic matrix to avoid local breakdown caused by agglomeration, reduce structural defects, and thus enhance dielectric properties. Furthermore, by controlling the mass ratio between the ceramic filler and the organic matrix, this invention ensures that the resulting flexible polymer composite film possesses both good flexibility and dielectric properties.

[0034] 3. When the flexible polymer composite film prepared by this invention is used for TTF electrode patch, the film thickness is controllable (20-50 micrometers), which can adapt to the curvature requirements of different treatment sites, significantly improving the durability of the device and the patient's treatment compliance.

[0035] 4. The flexible polymer composite film of the present invention does not require high-temperature sintering and can be formed at room temperature. It has the advantages of simple preparation process, low cost and environmental protection without pollution, and is suitable for large-scale production. Attached Figure Description

[0036] Figure 1 : Structural diagram of the flexible polymer layer in Example 1; wherein, 11-flexible circuit board substrate, 12-conductive layer, 13-flexible polymer layer;

[0037] Figure 2 XRD pattern of the flexible polymer composite film prepared in Example 1;

[0038] Figure 3 SEM image of the cross section of the flexible polymer composite membrane prepared in Example 1;

[0039] Figure 4 : Dielectric constant and dielectric loss diagram of the flexible polymer composite film prepared in Example 1;

[0040] Figure 5 XRD pattern of the flexible polymer composite film prepared in Example 2;

[0041] Figure 6 SEM image of the flexible polymer composite film prepared in Example 2;

[0042] Figure 7 Example 2: Dielectric constant and dielectric loss diagram of the flexible polymer composite film prepared;

[0043] Figure 8 : Dielectric constant and dielectric loss diagram of the flexible polymer composite film prepared in Example 3;

[0044] Figure 9 : Dielectric constant and dielectric loss diagram of the flexible polymer composite film prepared in Example 4;

[0045] Figure 10 : Dielectric constant and dielectric loss diagram of the flexible polymer composite film prepared in Example 5;

[0046] Figure 11 : Dielectric constant and dielectric loss diagram of the flexible polymer composite film prepared in Comparative Example 1;

[0047] Figure 12 : Dielectric constant and dielectric loss diagram of the flexible polymer composite film prepared in Comparative Example 2;

[0048] Figure 13 : Dielectric constant and dielectric loss diagram of the flexible polymer composite film prepared in Comparative Example 3;

[0049] Figure 14 : Dielectric constant and dielectric loss diagram of the flexible polymer composite film prepared in Comparative Example 4;

[0050] Figure 15 : Dielectric constant and dielectric loss diagram of the flexible polymer composite film prepared in Comparative Example 5. Detailed Implementation

[0051] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0052] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0053] The experimental materials used in the embodiments of this invention are all conventional experimental materials in the art and can be purchased through commercial channels.

[0054] Example 1: Flexible polymer composite film

[0055] 1. Composition

[0056] The flexible polymer composite membrane is prepared by mixing a coupling agent-modified ceramic filler and a multiphase organic matrix in a mass ratio of 30:70.

[0057] The multiphase organic matrix was prepared by mixing PVDF-HFP, TPU and PMMA in a mass ratio of 80:10:10 and stirring at 45°C for 2 hours.

[0058] The coupling agent modified ceramic filler is prepared by the following method: using spherical (Bi) fillers with a diameter of 50 nm. 0.2 Ba 0.6 Sr 0.1 (Ti) 0.8 Zr 0.2 O3 was used as piezoelectric ceramic particles. 1g of piezoelectric ceramic particles were added to 20mL of 98% ethanol, and then 0.05mL of 5wt% Tween-20 was added. The mixture was stirred for 12h to obtain the coupling agent modified ceramic filler.

[0059] 2. Preparation method:

[0060] (1) Disperse 1g of coupling agent modified ceramic filler in 10mL DMAC, sonicate at 300W for 30min, and then stir for 6h to obtain a dispersion of coupling agent modified ceramic filler; add 1.85g of multiphase organic matrix to 6mL MDAC, mix evenly to obtain a multiphase organic matrix solution.

[0061] (2) The coupling agent-modified ceramic filler dispersion was slowly added to the multiphase organic matrix solution and stirred for 12 hours to obtain a composite slurry. The composite slurry was coated onto a pre-flattened flexible circuit board substrate 11 and dried at 70°C for 12 hours to obtain a flexible polymer composite film 13. Gold electrode layers were sputtered onto both sides of the flexible polymer composite film 13 as conductive layers 12 to obtain a flexible polymer layer. A schematic diagram of the flexible polymer layer is shown below. Figure 1 As shown.

[0062] 3. Structural characterization:

[0063] The crystal structure and microstructure of the flexible polymer composite film were analyzed, and the results are as follows: Figure 2 and Figure 3 As shown.

[0064] Depend on Figure 2 It can be seen that the flexible polymer composite film prepared in this embodiment has the characteristics of (Bi) 0.2 Ba 0.6 Sr 0.1 (Ti) 0.8 Zr 0.2 The diffraction peaks of O3 and the amorphous diffraction peaks belonging to polymers. (By...) Figure 3 It can be seen that the flexible polymer composite membrane contains spherical ceramic particles with a thickness of about 25 micrometers. The structure is dense, without fractures or obvious pores.

[0065] 4. Performance Testing:

[0066] Circular gold electrodes were deposited on both sides of a flexible polymer composite film. The dielectric constant and dielectric loss were measured at room temperature in the frequency range of 100 kHz–1 MHz. The results are as follows: Figure 4 As shown.

[0067] Depend on Figure 4 It can be seen that, in the range of 100 kHz to 1 MHz, the prepared 35 wt% (Bi) 0.2 Ba 0.6 Sr 0.1 (Ti) 0.8 Zr 0.2 The O3 / PVDF-HFP&TPU&PMMA flexible composite dielectric material exhibits a decreasing dielectric constant with increasing frequency, but all values ​​remain above 30; the dielectric loss increases with increasing frequency, but all values ​​remain below 0.15. Furthermore, after repeated bending of the flexible polymer composite film 1000 times, no significant cracking was observed. Therefore, the flexible polymer composite film prepared in this embodiment possesses good flexibility.

[0068] Example 2: Flexible polymer composite film

[0069] 1. Composition

[0070] The flexible polymer composite membrane is prepared by mixing a coupling agent-modified ceramic filler and a multiphase organic matrix in a mass ratio of 25:75; wherein,

[0071] The multiphase organic matrix was prepared by mixing PVDF-TrFE, TPU and PMMA in a mass ratio of 90:5:5 and stirring at 45°C for 2 hours.

[0072] The coupling agent modified ceramic filler is prepared by the following method: using spherical (Ba) fillers with a diameter of 100 nm. 0.7 Sr0.3 (Ti) 0.9 Zr 0.1 O3 was used as piezoelectric ceramic particles. 1g of piezoelectric ceramic particles were added to 20mL of 98% ethanol, and then 0.01mL of 1wt% zirconate ester coupling agent was added. The mixture was stirred for 12h to obtain coupling agent modified ceramic filler.

[0073] 2. Preparation method:

[0074] (1) Disperse 1g of coupling agent modified ceramic filler in 10mL DMAC, sonicate at 250W for 25min, and then stir for 5.5h to obtain a dispersion of coupling agent modified ceramic filler; add 3g of multiphase organic matrix to 10mL MDAC, mix evenly to obtain a multiphase organic matrix solution.

[0075] (2) The coupling agent modified ceramic filler dispersion was slowly added to the multiphase organic matrix solution and stirred for 12 hours to obtain a composite slurry; the composite slurry was coated on a pre-flattened flexible circuit board substrate and dried at 70°C for 12 hours to obtain a flexible polymer composite film.

[0076] 3. Structural characterization:

[0077] The flexible polymer composite film prepared in this embodiment was subjected to XRD analysis and its cross-section was analyzed by electron microscopy. The results are as follows: Figure 5 and Figure 6 As shown.

[0078] Depend on Figure 5 It can be seen that the prepared flexible polymer composite film has the properties of (Ba 0.7 Sr 0.3 (Ti) 0.9 Zr 0.1 The diffraction peaks of O3 and the amorphous diffraction peaks belonging to polymers. (By...) Figure 6 It can be seen that the flexible polymer composite membrane contains spherical ceramic particles with a thickness of about 25 μm. The structure is dense, without fractures or obvious pores.

[0079] 4. Performance Testing:

[0080] Gold electrode layers were sputtered onto both sides of the flexible polymer composite film to assess its dielectric properties, and the results are as follows: Figure 7 As shown.

[0081] Depend on Figure 7It can be seen that the dielectric constant of the flexible polymer composite film prepared in this embodiment decreases with increasing frequency in the range of 100kHz to 1MHz, but remains above 24. Simultaneously, the dielectric loss gradually increases with increasing frequency, but remains less than 0.18. Furthermore, after repeated bending 1000 times, the flexible polymer composite film showed no significant cracking. Therefore, the flexible polymer composite film prepared in this embodiment exhibits good flexibility.

[0082] Example 3: Flexible polymer composite film

[0083] 1. Composition

[0084] The flexible polymer composite membrane is prepared by mixing a coupling agent-modified ceramic filler and a multiphase organic matrix in a mass ratio of 30:70; wherein,

[0085] The multiphase organic matrix was prepared by mixing P(VDF-TrFE-CFE), TPU and PMMA in a mass ratio of 98.9:1:0.1 and stirring at 55°C for 2.5 h.

[0086] The coupling agent modified ceramic filler is prepared by the following method: using spherical (Bi) fillers with a diameter of 20 nm. 0.1 Ba 0.5 Sr 0.35 (Ti) 0.7 Zr 0.3 O3 was used as piezoelectric ceramic particles. 1g of piezoelectric ceramic particles were added to 20mL of 98% ethanol, and then 0.02mL of 2wt% Tween-60 was added. The mixture was stirred for 12h to obtain the coupling agent modified ceramic filler.

[0087] 2. Preparation method:

[0088] (1) Disperse 1g of coupling agent modified ceramic filler in 10mL DMAC, sonicate at 350W for 35min, and then stir for 6.5h to obtain a dispersion of coupling agent modified ceramic filler; add 2.33g of multiphase organic matrix to 7.7mL MDAC, mix evenly to obtain a multiphase organic matrix solution;

[0089] (2) The coupling agent modified ceramic filler dispersion was slowly added to the multiphase organic matrix solution and stirred for 12 hours to obtain a composite slurry; the composite slurry was coated on a pre-flattened flexible circuit board substrate and dried at 75°C for 12 hours to obtain a flexible polymer composite film.

[0090] 3. Performance Testing:

[0091] Gold electrode layers were sputtered onto both sides of the flexible polymer composite film to assess its dielectric properties, and the results are as follows: Figure 8 As shown.

[0092] Depend on Figure 8 It can be seen that the dielectric constant of the flexible polymer composite film prepared in this embodiment decreases with increasing frequency in the range of 100kHz to 1MHz, but remains above 20. Simultaneously, the dielectric loss gradually increases with increasing frequency, but remains less than 0.18. Furthermore, after repeated bending 1000 times, the flexible polymer composite film showed no significant cracking. Therefore, the flexible polymer composite film prepared in this embodiment exhibits good flexibility.

[0093] Example 4: Flexible polymer composite film

[0094] 1. Composition

[0095] The flexible polymer composite membrane is prepared by mixing a coupling agent-modified ceramic filler and a multiphase organic matrix in a mass ratio of 35:65; wherein,

[0096] The multiphase organic matrix was prepared by mixing P(VDF-TrFE-CFE-CTFE), TPU and PMMA in a mass ratio of 60:20:20 and stirring at 45°C for 2 hours.

[0097] The coupling agent modified ceramic filler is prepared by the following method: using spherical (Bi) fillers with a diameter of 20 nm. 0.1 Ba 0.7 Sr 0.15 TiO3 was used as piezoelectric ceramic particles. 1g of piezoelectric ceramic particles were added to 20mL of 98% ethanol, and then 0.04mL of 4wt% titanate coupling agent was added. The mixture was stirred for 12h to obtain coupling agent modified ceramic filler.

[0098] 2. Preparation method:

[0099] (1) Disperse 1g of coupling agent modified ceramic filler in 10mL DMAC, sonicate at 300W for 30min, and then stir for 6h to obtain a dispersion of coupling agent modified ceramic filler; add 1.85g of multiphase organic matrix to 6mL MDAC, mix evenly to obtain a multiphase organic matrix solution.

[0100] (2) The coupling agent modified ceramic filler dispersion was slowly added to the multiphase organic matrix solution and stirred for 12 hours to obtain a composite slurry; the composite slurry was coated on a pre-flattened flexible circuit board substrate and dried at 70°C for 12 hours to obtain a flexible polymer composite film.

[0101] 3. Performance Testing:

[0102] Gold electrode layers were sputtered onto both sides of the flexible polymer composite film to assess its dielectric properties, and the results are as follows: Figure 9 As shown.

[0103] Depend on Figure 8 It can be seen that the dielectric constant of the flexible polymer composite film prepared in this embodiment decreases with increasing frequency in the range of 100kHz to 1MHz, but remains above 24. Simultaneously, the dielectric loss gradually increases with increasing frequency, but remains less than 0.15. Furthermore, after repeated bending 1000 times, the flexible polymer composite film showed no significant cracking. Therefore, the flexible polymer composite film prepared in this embodiment exhibits good flexibility.

[0104] Example 5: Flexible polymer composite film

[0105] 1. Composition

[0106] The flexible polymer composite membrane is prepared by mixing a coupling agent-modified ceramic filler and a multiphase organic matrix in a mass ratio of 20:80; wherein,

[0107] The multiphase organic matrix was prepared by mixing P(VDF-TrFE-CFE-CTFE), TPU and PMMA in a mass ratio of 70:15:15 and stirring at 45°C for 2 hours.

[0108] The coupling agent modified ceramic filler is prepared by the following method: using spherical (Bi) fillers with a diameter of 300 nm. 0.15 Ba 0.4 Sr 0.375 (Ti) 0.5 Zr 0.5 O3 was used as piezoelectric ceramic particles. 1g of piezoelectric ceramic particles were added to 20mL of 98% ethanol, and then 0.03mL of 3wt% aluminate coupling agent was added. The mixture was stirred for 12h to obtain coupling agent modified ceramic filler.

[0109] 2. Preparation method:

[0110] (1) Disperse 1g of coupling agent modified ceramic filler in 10mL DMAC, sonicate at 300W for 30min, and then stir for 6h to obtain a dispersion of coupling agent modified ceramic filler; add 4g of multiphase organic matrix to 20mL MDAC, mix evenly to obtain a multiphase organic matrix solution.

[0111] (2) The coupling agent modified ceramic filler dispersion was slowly added to the multiphase organic matrix solution and stirred for 12 hours to obtain a composite slurry; the composite slurry was coated on a pre-flattened flexible circuit board substrate and dried at 70°C for 12 hours to obtain a flexible polymer composite film.

[0112] 3. Performance Testing:

[0113] Gold electrode layers were sputtered onto both sides of the flexible polymer composite film to assess its dielectric properties, and the results are as follows: Figure 10 As shown.

[0114] Depend on Figure 10 It can be seen that the dielectric constant of the flexible polymer composite film prepared in this embodiment decreases with increasing frequency in the range of 100kHz to 1MHz, but remains above 20. Simultaneously, the dielectric loss gradually increases with increasing frequency, but remains less than 0.18. Furthermore, after repeated bending 1000 times, the flexible polymer composite film showed no significant cracking. Therefore, the flexible polymer composite film prepared in this embodiment exhibits good flexibility.

[0115] Comparative Example 1:

[0116] The difference between this comparative example and Example 1 is that the multiphase organic matrix in this example consists only of PVDF-HFP. The preparation method of the coupling agent modified ceramic filler and flexible polymer composite membrane is the same as in Example 1.

[0117] Gold electrode layers were sputtered onto both sides of the flexible polymer composite film to assess its dielectric properties, and the results are as follows: Figure 11 As shown.

[0118] Comparative Example 2:

[0119] The difference between this comparative example and Example 1 is that the multiphase organic matrix is ​​prepared by mixing PVDF-HFP and TPU at a mass ratio of 80:10 and stirring at 45°C for 2 hours.

[0120] The preparation method of the coupling agent modified ceramic filler and flexible polymer composite membrane is the same as in Example 1.

[0121] Gold electrode layers were sputtered onto both sides of the flexible polymer composite film to assess its dielectric properties, and the results are as follows: Figure 12 As shown.

[0122] Comparative Example 3:

[0123] The difference between this comparative example and Example 1 is that the multiphase organic matrix is ​​prepared by mixing PVDF-HFP and PMMA in a mass ratio of 80:10 and stirring at 45°C for 2 hours.

[0124] The preparation method of the coupling agent modified ceramic filler and flexible polymer composite membrane is the same as in Example 1.

[0125] Gold electrode layers were sputtered onto both sides of the flexible polymer composite film to assess its dielectric properties, and the results are as follows: Figure 13 As shown.

[0126] Comparative Example 4:

[0127] The difference between this comparative example and Example 1 is that the flexible polymer composite membrane is prepared by coupling agent modified ceramic filler and multiphase organic matrix in a mass ratio of 38:62.

[0128] The preparation method of the coupling agent modified ceramic filler, the multiphase organic matrix and the flexible polymer composite membrane is the same as that in Example 1.

[0129] Gold electrode layers were sputtered onto both sides of the flexible polymer composite film to assess its dielectric properties, and the results are as follows: Figure 14 As shown.

[0130] Depend on Figure 14 It can be seen that in the range of 100kHz to 1MHz, the dielectric constant of the prepared material decreases slightly with increasing frequency, and is always below 22; the dielectric loss first decreases and then increases with increasing frequency, but is always greater than 0.3. Cracks appeared in the composite material during a test involving 700 repeated bending cycles.

[0131] Comparative Example 5:

[0132] The difference between this comparative example and Example 1 is that the flexible polymer composite membrane is prepared by coupling agent modified ceramic filler and multiphase organic matrix in a mass ratio of 18:82.

[0133] The preparation method of the coupling agent modified ceramic filler, the multiphase organic matrix and the flexible polymer composite membrane is the same as that in Example 1.

[0134] Gold electrode layers were sputtered onto both sides of the flexible polymer composite film to assess its dielectric properties, and the results are as follows: Figure 15 As shown.

[0135] The dielectric constant and dielectric loss of the polymer composite films prepared in Examples 1-5 and Comparative Examples 1-5 at 1MHz are shown in Table 1.

[0136] Table 1. Dielectric constants and losses of the polymer composite films prepared in Examples 1-5 and Comparative Examples 1-5 at 1 MHz.

[0137] Group Dielectric constant @ 1MHz Dielectric loss @ 1MHz Example 1 30.8 0.12 Example 2 24.4 0.14 Example 3 22.5 0.17 Example 4 25.7 0.12 Example 5 21.0 0.17 Comparative Example 1 13.7 0.38 Comparative Example 2 16.7 0.39 Comparative Example 3 18.6 0.47 Comparative Example 4 18.5 0.37 Comparative Example 5 12.7 0.22

[0138] The polymer composite films prepared in Examples 1-5, as summarized in Table 1, exhibited excellent dielectric constant and dielectric loss at high frequency (1 MHz), meeting the requirements for dielectric properties in high-frequency applications: dielectric constants all above 20 and dielectric losses all below 0.18. In contrast, the polymer composite films prepared in Comparative Examples 1-5 showed dielectric constants below 20 and dielectric losses above 0.22. These significant performance differences highlight the effectiveness of the material composition and formulation design in the examples.

[0139] Experimental Example 1:

[0140] The composite films prepared in Examples 1-5 and Comparative Examples 1-5 were placed on a mechanical testing machine and subjected to tensile tests at a speed of 10 mm / min. The results are shown in Table 2.

[0141] Table 2. Tensile strength results of polymer composite films prepared in Examples 1-5 and Comparative Examples 1-5.

[0142] Group Tensile strength / MPa Elongation at break (%) Example 1 27.2 360 Example 2 28.2 365 Example 3 29.8 354 Example 4 28.7 350 Example 5 27.2 370 Comparative Example 1 20.5 210 Comparative Example 2 16.8 280 Comparative Example 3 21.8 130 Comparative Example 4 23.1 329 Comparative Example 5 23.5 315

[0143] As shown in Table 2, under the same conditions, the composite film prepared using pure PVDF-HFP (Comparative Example 1) has a tensile strength of approximately 20.5 MPa and an elongation at break of 210%. The composite film prepared by blending only TPU (Comparative Example 2) slightly reduces its tensile strength but helps increase its elongation at break. The composite film prepared by blending only PMMA (Comparative Example 3) slightly increases its tensile strength but significantly reduces its elongation at break. Adding appropriate amounts of PMMA and TPU to PVDF-HFP simultaneously results in a balance or competition among the three components, significantly increasing the tensile strength and elongation at break of the composite film. If the PMMA and TPU phase domains are too large, unevenly distributed, or have weak interfacial bonding with each other / with the matrix, they will become stress concentration points, causing the material to fail under lower stress and strain, significantly reducing its strength.

[0144] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A flexible polymer composite film, characterized in that, It is prepared by coupling agent modified ceramic filler and multiphase organic matrix in a mass ratio of (20-35):(65-80); The multiphase organic matrix is ​​composed of PVDF-based copolymer, polymethyl methacrylate and thermoplastic polyurethane mixed in a mass ratio of (60-98.9):(1-20):(0.1-20); The coupling agent-modified ceramic filler is prepared by the following method: piezoelectric ceramic particles are added to an organic solvent, and then a coupling agent is added and stirred to obtain the coupling agent-modified ceramic filler; the chemical formula of the piezoelectric ceramic particles is (Bi x Ba y Sr 1-1.5x-y (Ti) z Zr 1-z O3, where 0≤x≤0.2, 0≤y≤1-1.5x, and 0≤z≤1.

2. The flexible polymer composite film as described in claim 1, characterized in that, The coupling agent is one or more of zirconate coupling agents, aluminate coupling agents, titanate coupling agents, Tween-20, and Tween-60; the concentration of the coupling agent used is 1-5 wt%; the organic solvent is ethanol or isopropanol.

3. The flexible polymer composite film as described in claim 1, characterized in that, The ratio of piezoelectric ceramic particles, coupling agent solution and organic solvent added is 1g:(0.01-0.05)mL:20mL.

4. The flexible polymer composite film as described in claim 1, characterized in that, The PVDF-based copolymer is at least one of PVDF, PVDF-HFP, PVDF-TrEE, P(VDF-TrFE-CFE), and P(VDF-TrFE-CFE-CTFE).

5. The method for preparing the flexible polymer composite film according to any one of claims 1-4, characterized in that, Includes the following steps: (1) The coupling agent modified ceramic filler is dispersed in an organic solvent, and after ultrasonic treatment and stirring, a dispersion of the coupling agent modified ceramic filler is obtained; the multiphase organic matrix is ​​added to the organic solvent to obtain a multiphase organic matrix solution. (2) Add the coupling agent modified ceramic filler dispersion to the multiphase organic matrix solution and stir to obtain a composite slurry; coat the composite slurry onto the substrate and dry to obtain a flexible polymer composite film.

6. The method for preparing the flexible polymer composite film as described in claim 5, characterized in that, The organic solvent is dimethylacetamide and / or tetrahydrofuran.

7. The method for preparing the flexible polymer composite film as described in claim 5, characterized in that, In step (1), the ratio of the coupling agent-modified ceramic filler to the organic solvent is 1g:(8-12)mL; the ultrasonic power is 250-350W; the ultrasonic treatment time is 25-35min; and the stirring time is 5.5-6.5h.

8. The method for preparing the flexible polymer composite film as described in claim 5, characterized in that, In step (1), the ratio of the multiphase organic matrix to the organic solvent is (3-5) g: 10 mL.

9. The method for preparing the flexible polymer composite film as described in claim 5, characterized in that, In step (2), the thickness of the flexible polymer composite film is 20-50 μm.

10. The use of the flexible polymer composite film according to any one of claims 1-4 in the preparation of tumor therapeutic field patches.

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