Dielectric layer ion membrane, preparation method and application thereof

Abstract

This invention provides a dielectric ion exchange membrane, its preparation method, and its application, relating to the field of membrane material preparation technology. The dielectric ion exchange membrane includes a substrate and an ion exchange membrane coated on the surface of the substrate. The ion exchange membrane comprises polyvinyl alcohol, an ion system, a UV-curable monomer, and a photoinitiator. By using UV curing technology, the crosslinking process and solvent evaporation can be precisely controlled during membrane formation, ensuring a smooth membrane surface and avoiding membrane curling caused by uneven shrinkage. The introduction of the UV-curable monomer is to form a crosslinked network under UV irradiation, inhibiting macroscopic structural flow and creep of the ion exchange membrane during film formation and service, improving the mechanical stability of the membrane, and forming a stable crosslinked structure, thereby forming a structurally stable dielectric ion exchange membrane and effectively preventing membrane curling during drying.

Description

Technical Field

[0001] This invention relates to the field of membrane material preparation technology, and more specifically, to a dielectric ion membrane, its preparation method, and its application. Background Technology

[0002] Polyvinyl alcohol (PVA)-based ion exchange membranes are valuable in high-precision applications such as electronic devices, energy storage systems, and sensors due to their excellent conductivity and environmental stability. However, in actual fabrication, these membrane materials commonly suffer from film curling, which severely impairs surface smoothness and consequently affects their mechanical properties and application reliability. The root cause of curling lies in the uneven shrinkage behavior during solvent evaporation in the film formation stage. Specifically, when a PVA aqueous solution is coated onto the substrate surface, the initial liquid film appears smooth, but at this point, the PVA molecular chains are loosely bound only by intermolecular forces, and the ionic components are randomly dispersed in the matrix. As the water gradually evaporates, the PVA molecular chains rearrange and macroscopically relax. Simultaneously, the local aggregation of the ion system causes an imbalance in the internal stress distribution of the matrix, ultimately resulting in obvious wrinkles and overall warping of the membrane surface. This structural defect not only weakens the mechanical strength of the membrane but also leads to irregular surface microstructures, making it difficult to meet the stringent requirements for smoothness and stability of membrane materials in electrochemical sensors or energy storage devices. Summary of the Invention

[0003] The present invention aims to solve the problem of film curling in polyvinyl alcohol-based ion exchange membranes.

[0004] To address the above problems, this invention provides a dielectric ion membrane, its preparation method, and its application.

[0005] In a first aspect, the present invention provides a dielectric ion membrane, comprising a substrate and an ion membrane coated on the surface of the substrate, wherein the ion membrane comprises polyvinyl alcohol, an ion system, a UV-curable monomer and a photoinitiator, and the ion membrane is a cured film structure formed after being cured by ultraviolet light irradiation.

[0006] Optionally, the substrate is an ethylene-tetrafluoroethylene copolymer substrate.

[0007] Optionally, by weight, the ion exchange membrane comprises 65 to 75 parts polyvinyl alcohol, 1 to 10 parts ion system, 1 to 5 parts UV-curable monomer and 0.1 to 1 part photoinitiator.

[0008] Optionally, the ionic system includes one or more of sodium chloride, potassium chloride, ammonium acetate, citric acid, acetic acid, and phosphoric acid.

[0009] Optionally, the UV-curable monomer includes one or more of methyl methacrylate and acrylate.

[0010] Alternatively, the photoinitiator includes one or more of benzoyl peroxide and 2-hydroxy-2-methyl-1-phenyl-1-propanone.

[0011] Secondly, the present invention provides a method for preparing the dielectric layer ion film as described above, comprising the following steps: S1: Dissolve polyvinyl alcohol as the matrix in water to obtain a polyvinyl alcohol aqueous solution; S2: Add the ionic system to the polyvinyl alcohol aqueous solution and dissolve it to provide conductivity; S3: Add the UV-curable monomer to the polyvinyl alcohol aqueous solution and dissolve it; S4: Add the photoinitiator to the polyvinyl alcohol aqueous solution and stir to obtain the ion-exchange membrane solution; S5: The ion exchange membrane solution is coated onto the substrate surface and cured by ultraviolet light irradiation to obtain the dielectric ion exchange membrane. The ultraviolet light irradiation wavelength is 365 nm and the intensity is 50 to 100 mW / cm². 2 The irradiation time is 2 to 5 minutes.

[0012] Optionally, in S1, polyvinyl alcohol is dissolved in water at 85°C to 95°C and stirred for 2 to 3 hours.

[0013] Optionally, S4 further includes the following steps: The ion-exchange membrane solution is filtered through a 200-300 mesh filter membrane and then defoamed under vacuum at -0.08 MPa to -0.09 MPa for 15 to 20 minutes. S5 also includes the following steps: The dielectric ion membrane is heat-treated at 40°C to 50°C for 1 to 2 hours, and the ambient humidity is adjusted to 40% to 60% to make the water content of the dielectric ion membrane 10% to 15%.

[0014] Thirdly, the present invention provides an application of the dielectric ion membrane described above in the fields of electrochemical sensors and energy storage devices.

[0015] The beneficial effects of the dielectric ion exchange membrane, its preparation method, and its application of the present invention are as follows: Polyvinyl alcohol, as the matrix material, possesses good water solubility and membrane forming ability, providing a stable carrier for subsequent ion system dispersion and cross-linking structure construction, ensuring the basic forming performance and flexibility of the membrane. The addition of the ion system aims to impart conductivity to the dielectric ion exchange membrane. The ion system dissociates in aqueous solution, thereby providing conductive ions. Efficient ion migration is achieved through uniform dispersion, enabling the membrane to quickly respond to ion migration requirements under the action of an external electric field. The introduction of UV-curable monomers is to form a cross-linking network under ultraviolet light irradiation, inhibiting macroscopic structural flow and creep of the ion exchange membrane during film formation and service, improving the mechanical stability of the membrane, and thus stabilizing the membrane structure. The role of the photoinitiator is to absorb ultraviolet light energy and generate free radicals to promote the polymerization reaction of UV-curable monomers, improve cross-linking efficiency, and avoid forming a cross-linking network that dominates ion conduction, thus avoiding the limitation of ion conductivity by excessive cross-linking. This ensures that the UV-curable monomers are fully polymerized and cross-linked to form a stable cross-linking structure, thereby forming a structurally stable dielectric ion exchange membrane, effectively preventing the membrane from curling during the drying process. By employing UV curing technology, the crosslinking process and solvent evaporation can be precisely controlled during membrane formation, ensuring a smooth membrane surface and preventing membrane curling caused by uneven shrinkage. The UV curing process enhances the physical and chemical stability of the membrane, enabling it to remain flat and resistant to deformation during long-term use. This makes it suitable for high-precision and long-term applications, while also simplifying the membrane formation process, improving production efficiency, and reducing process complexity. Through optimized crosslinking structure of the polyvinyl alcohol matrix-ion system, the membrane's conductivity and mechanical strength are significantly improved, ensuring its reliability and stability in electrochemical sensors, energy storage devices, and other fields. Attached Figure Description

[0016] Figure 1 This is a schematic flowchart of the method for preparing the dielectric layer ion membrane according to an embodiment of the present invention; Figure 2 This is a front view of the dielectric ion membrane of Example 1; Figure 3 This is a side view of the dielectric ion membrane of Example 1; Figure 4 This is a surface roughness test curve of the dielectric ion film in Example 1; Figure 5 The capacitance test curve of the dielectric ion membrane in Example 1 is shown. Figure 6 This is a front view of the ion exchange membrane in Comparative Example 1; Figure 7 This is a side view of the ion exchange membrane in Comparative Example 1. Figure 8The surface roughness test curve of the ion exchange membrane in Comparative Example 1 is shown. Figure 9 The figure shows the capacitance test curve of the ion exchange membrane in Comparative Example 1. Detailed Implementation

[0017] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0018] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this invention's description is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "comprising" and its variations are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the description below. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0019] In related technologies, heat treatment and drying process control are mainly used to attempt to solve the curling problem, but these methods have significant limitations. During heat treatment, the temperature gradient is difficult to control precisely, easily leading to differences in shrinkage rates in different regions of the membrane, which in turn exacerbates stress concentration. In the drying process, small fluctuations in humidity and drying rate can cause uneven local shrinkage, making it impossible to maintain a uniform and flat membrane surface. Furthermore, traditional methods lack a real-time response mechanism for controlling solvent evaporation kinetics, failing to effectively coordinate molecular chain rearrangement and ion distribution, making the curling problem particularly prominent in high-precision applications. For example, in electrochemical sensors, uneven membrane surface directly affects the electrode interface contact quality, causing signal drift and detection errors; in energy storage devices, it may cause poor electrode-electrolyte interface contact, reducing energy conversion efficiency and device lifespan. These problems severely restrict the widespread use of polyvinyl alcohol-based ion exchange membranes in high-end fields, highlighting the shortcomings of existing preparation processes in stress control and morphological stability.

[0020] To address the problems existing in the aforementioned related technologies, embodiments of the present invention provide a dielectric ion membrane, its preparation method, and its application.

[0021] An embodiment of the present invention provides a dielectric ion membrane, comprising a substrate and an ion membrane coated on the surface of the substrate, wherein the ion membrane comprises polyvinyl alcohol, an ion system, a UV-curable monomer and a photoinitiator, and the ion membrane is a cured film structure formed after being cured by ultraviolet light irradiation.

[0022] Specifically, polyvinyl alcohol (PVA) is a water-soluble polymer compound used in this embodiment as the matrix material of the ion exchange membrane, providing basic structural support for the membrane. PVA powder with a degree of polymerization of 1700 to 2500 is preferred, as it possesses good water solubility and membrane forming ability, providing a stable carrier for the dispersion and cross-linking structure construction of the ion system, and ensuring the basic forming performance and flexibility of the membrane.

[0023] Ionic system: refers to a substance that can dissociate and generate free ions. It is added to a polyvinyl alcohol aqueous solution to provide core ionic conductivity for the ion membrane, aiming to endow the dielectric layer ion membrane with conductivity. Organic acids (citric acid or acetic acid), weak electrolyte salts (ammonium acetate), neutral salts (sodium chloride or potassium chloride) or combinations thereof are preferred. Efficient ion migration is achieved through uniform dispersion, so that the dielectric layer ion membrane can quickly respond to the ion migration demand under the action of an external electric field.

[0024] UV-curable monomers: These are monomer molecules that can undergo polymerization reactions under ultraviolet light irradiation. They are introduced to form a cross-linked network during the curing process, thereby stabilizing the structure of the dielectric ion membrane.

[0025] Photoinitiator: A substance that can absorb light energy and generate free radicals under ultraviolet light irradiation, and its function is to initiate the polymerization reaction of UV-curable monomers.

[0026] UV curing: refers to the process of using UV light of a specific wavelength, intensity and time to irradiate the ion membrane liquid coated on the surface of the substrate, causing the UV curing monomers inside to undergo a polymerization and cross-linking reaction, thereby transforming the liquid membrane liquid into a solid dielectric ion membrane.

[0027] Dielectric layer ion membrane: refers to a thin film with specific dielectric and ionic conductivity obtained by the preparation method of this application, which has a stable structure and a smooth surface.

[0028] In this embodiment, polyvinyl alcohol (PVA) is used as the matrix material. It possesses good water solubility and membrane forming ability, providing a stable carrier for subsequent ion system dispersion and cross-linking structure construction. This ensures the basic forming performance and flexibility of the membrane. Products with different molecular weights and degrees of hydrolysis can be selected. PVA can be dissolved at room temperature by prolonged stirring, or by stirring under appropriate heating conditions, to ensure complete dissolution and the formation of a homogeneous PVA aqueous solution. For example, PVA powder can be slowly added to deionized water, followed by continuous stirring until completely dissolved. The addition of the ion system aims to impart conductivity to the dielectric layer ion membrane. Efficient ion migration is achieved through uniform dispersion, enabling the membrane to quickly respond to ion migration demands under an external electric field. Various water-soluble inorganic salts or organic acids can be used as the ion system. For example, appropriate amounts of salts such as sodium chloride, potassium chloride, and lithium nitrate, or acids such as acetic acid and citric acid, can be added. These ion systems dissociate in the aqueous solution, thereby providing conductive ions. The introduction of UV-curable monomers aims to form a cross-linked network under UV irradiation, inhibiting macroscopic structural flow and creep of the ion exchange membrane during film formation and service, thus improving the membrane's mechanical stability and stabilizing its structure. Various photopolymerizable monomers can be selected, such as methacrylic acid, acrylic acid, and hydroxyethyl acrylate. These monomers require thorough stirring after addition to ensure uniform dispersion and dissolution in the polyvinyl alcohol aqueous solution. The photoinitiator absorbs UV energy and generates free radicals to promote the polymerization reaction of the UV-curable monomers and improve cross-linking efficiency. Various commercially available photoinitiators can be selected, such as benzoyl peroxide, benzophenone, benzoin ether, and photoinitiator 1173. After addition, thorough stirring is necessary to ensure uniform distribution throughout the system, forming a homogeneous ion exchange membrane solution, preparing for subsequent curing steps. Introducing a small amount of UV-curable cross-linked structure to prevent the polyvinyl alcohol ion exchange membrane from curling relies on the cross-linked network's structural locking and stress homogenization of the polyvinyl alcohol matrix. Ion exchange membrane solutions can be coated onto the substrate surface using various methods, such as blade coating, cast coating, spraying, or dip coating. After coating, the substrate coated with the ion exchange membrane solution is placed under ultraviolet light irradiation for curing, forming a stable cross-linked structure and thus a structurally stable dielectric ion exchange membrane. This effectively prevents the membrane from curling during the drying process. Ultraviolet curing technology allows for precise control of the cross-linking process and solvent evaporation during membrane forming, ensuring a smooth membrane surface and avoiding membrane curling caused by uneven shrinkage. The ultraviolet curing process enhances the physical and chemical stability of the membrane, enabling it to remain flat and less prone to deformation during long-term use. This makes it suitable for high-precision and long-term applications, simplifies the membrane forming process, improves production efficiency, and reduces process complexity.Through rational cross-linking structure optimization of the polyvinyl alcohol matrix-ion system, the conductivity and mechanical strength of the membrane are significantly improved, thereby ensuring its reliability and stability in fields such as electrochemical sensors and energy storage devices.

[0029] Optionally, the substrate is an ethylene-tetrafluoroethylene copolymer substrate.

[0030] Optionally, by weight, the ion exchange membrane comprises 65 to 75 parts polyvinyl alcohol, 1 to 10 parts ion system, 1 to 5 parts UV-curable monomer and 0.1 to 1 part photoinitiator.

[0031] Specifically, the obtained polyvinyl alcohol has a mass fraction of 65% to 75%. As the main component of the ion exchange membrane, polyvinyl alcohol (PVA) powder with a degree of polymerization of 1700 to 2500 is preferred. It has good water solubility and membrane forming ability, provides a stable carrier for the dispersion of the ion system and the construction of the cross-linked structure, and ensures the basic forming performance and flexibility of the membrane.

[0032] The ionic system is a key component providing conductivity to the dielectric ion exchange membrane. Precise control of its mass percentage is crucial for ensuring uniform ion dispersion within the polyvinyl alcohol matrix. If the mass percentage of the ionic system is too low, the membrane's conductivity may be insufficient, failing to meet application requirements; if the mass percentage is too high, ions may locally aggregate in the solution, forming uneven regions and affecting the membrane's structural stability. Specifically, during preparation, the amount of ionic system added can be calculated and adjusted by accurately weighing the ionic system and combining it with the total mass of the aqueous solution, ensuring that its final mass percentage falls within the range of 1% to 10%. For example, stock solutions of different concentrations of ionic system can be prepared in advance, and the added ionic system mass can be controlled by precisely measuring the volume of the stock solution; alternatively, during mixing, the concentration change of the ionic system can be monitored online, and the addition rate adjusted in real time to ensure that the mass percentage of the ionic system in the final mixture meets the requirements.

[0033] "The mass percentage of UV-curable monomer is 1% to 5%" refers to the mass percentage of UV-curable monomer in the entire aqueous solution. Determining this mass percentage is crucial for the performance of the final dielectric ion-exchange membrane. In practice, this can be controlled by accurately weighing the mass of the UV-curable monomer and the polyvinyl alcohol aqueous solution, and then mixing them according to a preset ratio. For example, a certain amount of polyvinyl alcohol aqueous solution can be weighed first, and then the corresponding mass of UV-curable monomer can be calculated and weighed according to the required mass percentage, and then added and stirred evenly. The setting of this mass percentage range aims to ensure that a sufficient and uniform cross-linked network can be formed during the subsequent UV curing process, while avoiding membrane performance defects caused by excessively high or low monomer content.

[0034] After the photoinitiator is added to the polyvinyl alcohol aqueous solution, stirring is performed to ensure that the photoinitiator can be fully dissolved and uniformly dispersed in the polyvinyl alcohol aqueous solution.

[0035] The mass percentage of the photoinitiator is precisely controlled within the range of 0.1% to 1%. This range is designed to optimize the initiation efficiency of the photoinitiator, thereby promoting the polymerization reaction of UV-curable monomers and improving crosslinking efficiency. For example, when the mass percentage of the photoinitiator is close to 0.1%, sufficient initiation activity is ensured to initiate the UV curing reaction, while minimizing potential side reactions or increased material costs caused by excessive initiator. Conversely, when the mass percentage is close to 1%, stronger initiation capability is provided, suitable for scenarios requiring rapid curing or processing thicker film layers, ensuring sufficient crosslinking within the set UV irradiation time. Midpoints within this range, such as 0.3%, 0.5%, or 0.8%, can be flexibly adjusted according to the specific polyvinyl alcohol aqueous solution formulation, the type of UV-curable monomer, and the required curing rate and final film properties.

[0036] In this optional embodiment, the mass fraction of polyvinyl alcohol is 65% to 75%. As the main component of the ion exchange membrane, it possesses good water solubility and membrane forming ability, providing a stable carrier for the dispersion of the ion system and the construction of the cross-linked structure, ensuring the basic forming performance and flexibility of the membrane. Limiting the mass percentage of the ion system to the range of 1% to 10% can effectively solve the membrane curling problem caused by uneven ion distribution. At this mass percentage, the ion system can be uniformly dispersed in the polyvinyl alcohol aqueous solution, avoiding local aggregation and stress concentration caused by excessively high ion concentration. This uniform distribution not only optimizes the ion transport path in the membrane and maintains the necessary conductivity, but more importantly, it reduces the macroscopic relaxation of the matrix and stress imbalance caused by local ion aggregation during the film formation process, thereby effectively preventing wrinkles and overall warping of the membrane surface. This results in a dielectric ion exchange membrane with better flatness and structural stability, thereby improving the mechanical properties and application effects of the membrane. By precisely controlling the mass percentage of UV-curable monomers in the aqueous solution, the problem of uneven monomer distribution can be effectively solved. By controlling the mass percentage of UV-curable monomers within the range of 1% to 5%, sufficient crosslinking density is ensured to form a stable film structure. This avoids excessive internal stress during curing due to excessively high monomer concentration, or insufficient crosslinking due to excessively low concentration, which would affect the mechanical strength and stability of the film. A moderate crosslinking density is maintained, resulting in a crosslinking network with a balanced density (uniform distribution of microstructure nodes). This approach enhances mechanical stability and reduces hysteresis by locking the film structure through crosslinking, while avoiding the formation of a dense network that blocks ion channels. Therefore, ion conductivity remains at a high level, achieving optimal performance in all three core aspects. The cross-linking density is crucial; if it is too low, the cross-linking network is loose (few microstructure nodes), and there is no significant obstruction to ion migration channels, resulting in high ionic conductivity but poor mechanical stability and a significant hysteresis effect. This is reflected in the low values ​​of mechanical stability and hysteresis effect in the curve, failing to meet practical requirements. Conversely, if the cross-linking density is too high, the cross-linking network is too dense (dense microstructure nodes). While this further improves mechanical stability, the ion migration channels are blocked by the cross-linking network, leading to a sharp drop in ionic conductivity. Simultaneously, the hysteresis effect intensifies, causing a significant decline in conductivity in the curve, demonstrating the negative impact of excessive cross-linking. This precise control allows for the formation of a uniform cross-linking network during subsequent UV curing, effectively suppressing curling and surface unevenness caused by solvent evaporation and uneven local stress during the film forming process. Ultimately, the prepared dielectric ion exchange membrane exhibits superior flatness, mechanical stability, and consistency, improving its reliability in various application scenarios. In the process of preparing dielectric ion membranes, precisely controlling the mass ratio of the photoinitiator in the aqueous solution after its addition can effectively ensure that the photoinitiator is fully and uniformly dissolved in the entire solution system. This aims to optimize the initiation efficiency of the photoinitiator, so as to promote the polymerization reaction of UV-curable monomers and improve crosslinking efficiency.This uniformity avoids inconsistent curing rates in subsequent UV curing processes, thus preventing internal stress accumulation and imbalance caused by uneven curing. Ultimately, this significantly improves the curing uniformity of the dielectric ion exchange film, effectively suppressing curling and surface unevenness during the forming process. This results in a dielectric ion exchange film with superior flatness and stability, thereby enhancing its reliability and performance in various applications.

[0037] Optionally, the ionic system includes one or more of sodium chloride, potassium chloride, ammonium acetate, citric acid, acetic acid, and phosphoric acid.

[0038] Specifically, the ionic system is the core component that enables the conductivity of the dielectric ion membrane. Its role is to provide mobile ion carriers, thereby giving the membrane material conductivity. During the fabrication process, the uniform dispersion of the ionic system is crucial to the membrane's performance. Uneven ion distribution can lead to differences in charge density within the membrane, resulting in localized stress and affecting the membrane's flatness.

[0039] Sodium chloride and potassium chloride are common inorganic salts with good water solubility and ionization ability, providing high concentrations of sodium, potassium, and chloride ions, thus effectively enhancing the ionic conductivity of the dielectric ion exchange membrane. These two salts are stable and uniformly dispersed in aqueous solution, rarely precipitating or locally agglomerating, which helps maintain the homogeneity of the system. Ammonium acetate, citric acid, acetic acid, and phosphoric acid, as acidic substances, not only provide hydrogen ions and adjust the pH of the system, but may also further promote the uniform dispersion and stable existence of the ion system in polyvinyl alcohol aqueous solution by forming hydrogen bonds or other weak interactions with the polyvinyl alcohol matrix, reducing ion migration and local enrichment during the drying process. Furthermore, the introduction of ammonium acetate, citric acid, acetic acid, and phosphoric acid also helps optimize the overall structural stability of the membrane and enhance its mechanical properties.

[0040] In this optional embodiment, by selecting sodium chloride, potassium chloride, ammonium acetate, citric acid, acetic acid, and phosphoric acid as the ionic system, the potential problem of local aggregation of ionic systems in polyvinyl alcohol aqueous solutions is effectively solved. These specific ionic components have excellent water solubility and dispersibility, enabling them to form a stable and uniformly distributed ionic environment in polyvinyl alcohol aqueous solutions. During the subsequent coating and curing processes, this uniform ionic distribution significantly reduces local ion enrichment and concentration gradients caused by solvent evaporation, thereby avoiding stress imbalance within the substrate. This allows the dielectric ion exchange membrane to remain flat during film formation, effectively preventing membrane curling and surface unevenness, ensuring the mechanical properties and application effects of the membrane. Simultaneously, these ionic components also guarantee good conductivity of the membrane, providing a foundation for the stable operation of the dielectric ion exchange membrane.

[0041] Optionally, the UV-curable monomer includes one or more of methyl methacrylate and acrylate.

[0042] Specifically, UV-curable monomers refer to compounds that can undergo polymerization or cross-linking reactions under ultraviolet light irradiation. Their role is to fix polymer chains by forming cross-linked networks, thereby endowing materials with specific mechanical properties, thermal stability, and dimensional stability. In the preparation of dielectric ion exchange membranes, UV-curable monomers are key components for achieving membrane curing and preventing membrane curling. Besides methyl methacrylate and acrylates, common UV-curable monomers include epoxy acrylates, polyurethane acrylates, and polyester acrylates, which, through different functional groups and molecular structures, form cross-linked structures with different characteristics under ultraviolet light initiation. Methyl methacrylate is a common acrylate monomer with high reactivity and good polymerization performance. In UV curing systems, methyl methacrylate can rapidly undergo free radical polymerization to form high molecular weight polymer chains and participate in the construction of cross-linked networks. Its characteristics include fast curing speed, high hardness, good transparency, and good compatibility with various polymer matrices. Acrylates are a class of compounds containing acrylate functional groups that can undergo rapid free radical polymerization reactions under ultraviolet light irradiation. There are many types of acrylate monomers, including but not limited to butyl acrylate, isooctyl acrylate, and hydroxyethyl acrylate, which can be selected according to the required properties of the film, such as flexibility, hardness, and adhesion. The introduction of acrylates helps to adjust the density and flexibility of the cured network, thereby optimizing the overall performance of the dielectric ion exchange film.

[0043] In this optional embodiment, the UV-curable monomer is specifically limited to one or more of methyl methacrylate and acrylate, which can effectively solve the problem of poor curing effect caused by improper monomer selection. Methyl methacrylate and acrylate, as preferred UV-curable monomers, have specific photoreactive activities and molecular structures, and can rapidly initiate cross-linking reactions under ultraviolet light irradiation to form a dense cross-linked network. This rapid and uniform cross-linking process can effectively fix the polyvinyl alcohol molecular chains, inhibit their rearrangement and macroscopic relaxation during solvent evaporation, thereby significantly reducing uneven film shrinkage. Simultaneously, these monomers have good compatibility with the polyvinyl alcohol matrix, can be uniformly dispersed in polyvinyl alcohol aqueous solutions, avoid local stress concentration, ensure a smooth film surface during curing, and effectively prevent film curling and warping. Furthermore, the formed cross-linked network enhances the mechanical strength and shrinkage resistance of the film, improving the overall stability and durability of the dielectric ion membrane.

[0044] Alternatively, the photoinitiator includes one or more of benzoyl peroxide and 2-hydroxy-2-methyl-1-phenyl-1-propanone.

[0045] Specifically, benzoyl peroxide is a commonly used organic peroxide that decomposes under ultraviolet light or heat to generate free radicals, thereby initiating the polymerization reaction of UV-curable monomers. Its advantage lies in providing a stable free radical source, effectively promoting the formation of cross-linked structures and ensuring the efficiency of the curing process. 2-Hydroxy-2-methyl-1-phenyl-1-propanone is a highly efficient free radical photoinitiator, belonging to the α-hydroxy ketone class. This initiator rapidly decomposes under ultraviolet light to generate highly reactive free radicals, thereby initiating the polymerization and cross-linking of UV-curable monomers. Its advantages include fast curing speed, high initiation efficiency, and minimal yellowing during curing, helping to maintain the transparency and appearance quality of the film.

[0046] In this optional embodiment, by selecting one or more of benzoyl peroxide and 2-hydroxy-2-methyl-1-phenyl-1-propanone as photoinitiators, this application can ensure the high efficiency and uniformity of the UV curing reaction. These specific photoinitiators have excellent free radical generation efficiency and reactivity, and can rapidly and uniformly initiate the polymerization and crosslinking of UV-curable monomers under UV irradiation. This efficient and uniform curing process effectively avoids film structure instability and local stress imbalance caused by insufficient or uneven curing, thereby significantly suppressing the curling phenomenon that may occur during the film forming process. At the same time, by precisely controlling the crosslinking reaction, a stable composite structure is formed between the polyvinyl alcohol matrix and the crosslinking network, further enhancing the flatness, mechanical stability, and overall performance of the dielectric ion membrane.

[0047] like Figure 1 As shown, another embodiment of the present invention provides a method for preparing a dielectric ion membrane, comprising the following steps: S1: Dissolve polyvinyl alcohol as the matrix in water to obtain a polyvinyl alcohol aqueous solution; S2: Add the ionic system to the polyvinyl alcohol aqueous solution and dissolve it to provide conductivity; S3: Add the UV-curable monomer to the polyvinyl alcohol aqueous solution and dissolve it; S4: Add the photoinitiator to the polyvinyl alcohol aqueous solution and stir to obtain the ion-exchange membrane solution; S5: The ion exchange membrane solution is coated onto the substrate surface and cured by ultraviolet light irradiation to obtain the dielectric ion exchange membrane. The ultraviolet light irradiation wavelength is 365 nm and the intensity is 50 to 100 mW / cm². 2 The irradiation time is 2 to 5 minutes.

[0048] Ion membrane solution: refers to a liquid formed by uniformly mixing polyvinyl alcohol aqueous solution, ion system, UV curable monomer and photoinitiator. It is a direct precursor for preparing dielectric layer ion membranes.

[0049] The thickness of the ion exchange membrane liquid coated on the substrate surface can be from 50 μm to 100 μm.

[0050] In this embodiment, polyvinyl alcohol (PVA) is used as the matrix material. It possesses good water solubility and membrane forming ability, providing a stable carrier for subsequent ion system dispersion and cross-linking structure construction. This ensures the basic forming performance and flexibility of the membrane. Products with different molecular weights and degrees of hydrolysis can be selected. PVA can be dissolved at room temperature by prolonged stirring, or by stirring under appropriate heating conditions, to ensure complete dissolution and the formation of a homogeneous PVA aqueous solution. For example, PVA powder can be slowly added to deionized water, followed by continuous stirring until completely dissolved. The addition of the ion system aims to impart conductivity to the dielectric layer ion membrane. Efficient ion migration is achieved through uniform dispersion, enabling the membrane to quickly respond to ion migration demands under an external electric field. Various water-soluble inorganic salts or organic acids can be used as the ion system. For example, appropriate amounts of salts such as sodium chloride, potassium chloride, and lithium nitrate, or acids such as acetic acid and citric acid, can be added. These ion systems dissociate in the aqueous solution, thereby providing conductive ions. The introduction of UV-curable monomers aims to form a cross-linked network under UV irradiation, inhibiting macroscopic structural flow and creep of the ion exchange membrane during film formation and service, thus improving the membrane's mechanical stability and stabilizing its structure. Various photopolymerizable monomers can be selected, such as methacrylic acid, acrylic acid, and hydroxyethyl acrylate. These monomers require thorough stirring after addition to ensure uniform dispersion and dissolution in the polyvinyl alcohol aqueous solution. The photoinitiator absorbs UV energy and generates free radicals to promote the polymerization reaction of the UV-curable monomers and improve cross-linking efficiency. Various commercially available photoinitiators can be selected, such as benzoyl peroxide, benzophenone, benzoin ether, and photoinitiator 1173. After addition, thorough stirring is necessary to ensure uniform distribution throughout the system, forming a homogeneous ion exchange membrane solution, preparing for subsequent curing steps. Introducing a small amount of UV-curable cross-linked structure to prevent the polyvinyl alcohol ion exchange membrane from curling relies on the cross-linked network's structural locking and stress homogenization of the polyvinyl alcohol matrix. The ion exchange membrane solution can be coated onto the substrate surface using various methods, such as blade coating, cast coating, spraying, or dip coating. After coating, the substrate coated with the ion exchange membrane solution is placed under ultraviolet light irradiation for curing. The wavelength of the ultraviolet light irradiation is set to 365 nm, and the intensity is controlled between 50 and 100 mW / cm². 2Within the specified range, the irradiation time is 2 to 5 minutes. By accurately controlling these parameters, a cross-linked network that dominates ion conduction is not formed, avoiding the limitation of ion conductivity due to excessive cross-linking. This ensures that the UV-cured monomers are fully polymerized and cross-linked, forming a stable cross-linked structure, thus creating a structurally stable dielectric ion membrane and effectively preventing membrane curling during drying. Through UV curing and shaping technology, the surface of the membrane is ensured to be smooth by precisely controlling the cross-linking process and solvent evaporation during membrane forming, avoiding membrane curling caused by uneven shrinkage. The UV curing process enhances the physical and chemical stability of the membrane, enabling it to remain smooth and less prone to deformation during long-term use, making it suitable for high-precision and long-term applications. It also simplifies the membrane forming process, improves production efficiency, and reduces process complexity. Through reasonable cross-linking structure optimization of the polyvinyl alcohol matrix-ion system, the conductivity and mechanical strength of the membrane are significantly improved, ensuring its reliability and stability in electrochemical sensors, energy storage devices, and other fields.

[0051] Optionally, in S1, polyvinyl alcohol is dissolved in water at 85°C to 95°C and stirred for 2 to 3 hours.

[0052] Specifically, polyvinyl alcohol (PVA) dissolves in water at a temperature between 85°C and 95°C. This temperature range is designed to ensure that PVA molecules swell rapidly and dissolve uniformly, avoiding incomplete dissolution at lower temperatures or molecular degradation that may occur at excessively high temperatures, thus ensuring a homogeneous solution free of particles. This dissolution process can be achieved in several ways. For example, a constant-temperature water bath or jacketed reactor equipped with a precise temperature control system can be used to stably maintain the water temperature between 85°C and 95°C, and PVA can be slowly added at this temperature with continuous stirring until completely dissolved. Alternatively, microwave-assisted heating technology can be used. By precisely controlling the microwave power and time, the water temperature can be rapidly and uniformly reached and maintained within the 85°C to 95°C range, thereby efficiently dissolving PVA.

[0053] In this optional embodiment, the preparation process of the matrix solution is optimized by precisely controlling the dissolution temperature of polyvinyl alcohol. Specifically, polyvinyl alcohol is dissolved in water at a temperature range of 85°C to 95°C, ensuring that the polyvinyl alcohol molecular chains can fully extend and disperse uniformly. This effectively avoids agglomeration or undissolved particles formed due to incomplete dissolution, which may become stress concentration points during the subsequent film formation process, resulting in uneven film surface.

[0054] In some specific embodiments, the concentration of the obtained polyvinyl alcohol aqueous solution is 5% to 20%. This concentration range is determined to optimize the viscosity and flowability of the solution, facilitating subsequent mixing and coating operations while ensuring the strength and uniformity of the final film. This precise control of dissolution conditions and solution concentration significantly improves the uniformity and stability of the polyvinyl alcohol aqueous solution, resulting in a smoother and more uniform coating during subsequent coating and UV curing processes. This effectively suppresses uneven shrinkage of the film during drying and curing due to uneven solvent evaporation or molecular rearrangement, significantly reducing film curling and wrinkling, and laying a solid foundation for preparing dielectric ion-exchange films with excellent smoothness and stability. In practical operation, the final solution concentration can be ensured to fall within the range of 5% to 20% by accurately weighing the mass of polyvinyl alcohol and the volume of water according to the preset mass percentage. For example, to prepare 100 grams of solution, 5 to 20 grams of polyvinyl alcohol can be weighed and the corresponding mass of water added. Another approach is to use an online viscometer or densitometer to monitor the physical parameters of the solution in real time during the dissolution process, and dynamically adjust the amount of polyvinyl alcohol or water added based on a pre-established concentration-viscosity / density curve to precisely control the solution concentration within the target range.

[0055] Polyvinyl alcohol, ionic system, UV curable monomer and photoinitiator are all dissolved in water. The concentration of polyvinyl alcohol is controlled at 5% to 20%, the mass fraction of ionic system is 1% to 10%, the mass fraction of UV curable monomer is 1% to 5%, and the mass fraction of photoinitiator is 0.1% to 1%.

[0056] In some optional embodiments, in S2, after the ion system is added to the polyvinyl alcohol aqueous solution, it is stirred for 30 to 60 minutes to make the mass fraction of the ion system 1% to 10%. The stirring operation can effectively solve the membrane curling problem caused by uneven distribution of the ion system.

[0057] In some optional embodiments, in S3, after the UV-curable monomer is added to the polyvinyl alcohol aqueous solution, it is stirred for 15 to 30 minutes to make the mass fraction of the UV-curable monomer 1% to 5%.

[0058] Specifically, "stirring for 15 to 30 minutes" refers to continuously agitating the mixture after adding the UV-curable monomer to the polyvinyl alcohol aqueous solution using mechanical or physical methods to promote the dissolution and uniform dispersion of the monomer. This stirring process can be achieved in various ways. For example, a mechanical stirrer with a stirring paddle can be used, and the mixing effect can be optimized by adjusting the shape (such as propeller, anchor, or blade type) and speed of the stirring paddle; or, for small-batch preparation, a magnetic stirrer can be used in conjunction with a stir bar to ensure that the solution is fully mixed within the specified time.

[0059] In this optional embodiment, by precisely controlling the stirring time and mass ratio of the UV-curable monomer in the polyvinyl alcohol aqueous solution, the problem of uneven monomer distribution can be effectively solved. Setting the stirring time to 15 to 30 minutes ensures that the UV-curable monomer has sufficient time to fully dissolve and uniformly disperse in the polyvinyl alcohol aqueous solution, avoiding localized monomer aggregation caused by insufficient stirring.

[0060] In some optional embodiments, in S4, after the photoinitiator is added to the polyvinyl alcohol aqueous solution, it is stirred for 10 to 15 minutes to make the mass fraction of the photoinitiator 0.1% to 1%.

[0061] Specifically, stirring can be achieved in several ways. For example, a magnetic stirrer with a stir bar can be used to mix, and the mixing effect can be optimized by adjusting the stirring speed. Alternatively, a mechanical stirrer can be used, selecting appropriate impellers (such as anchor, paddle, or turbine types) to adapt to solutions of different viscosities. Furthermore, for some difficult-to-disperse systems, ultrasonic dispersion technology can be considered, using ultrasonic vibration to promote the depolymerization and uniform distribution of the photoinitiator. The specified stirring time of 10 to 15 minutes is based on experimental optimization and aims to provide sufficient time for the photoinitiator to achieve a uniform distribution, avoiding localized concentration differences caused by insufficient stirring.

[0062] In this optional embodiment, precisely controlling the stirring time and mass ratio of the photoinitiator in the aqueous solution after its addition during the preparation of the dielectric ion exchange membrane effectively ensures the uniform dispersion and complete dissolution of the photoinitiator throughout the solution system. This aims to optimize the initiation efficiency of the photoinitiator, thereby promoting the polymerization reaction of UV-curable monomers and improving crosslinking efficiency. This uniformity avoids inconsistent curing rates in subsequent UV curing processes, preventing internal stress accumulation and imbalance caused by uneven curing. Ultimately, this significantly improves the curing uniformity of the dielectric ion exchange membrane, effectively suppressing curling and surface unevenness during the forming process. The resulting dielectric ion exchange membrane exhibits superior flatness and stability, thus enhancing its reliability and performance in various applications.

[0063] Optionally, S4 further includes the following steps: The ion-exchange membrane solution is filtered through a 200-300 mesh filter membrane and then defoamed under vacuum at -0.08 MPa to -0.09 MPa for 15 to 20 minutes.

[0064] Specifically, the ion exchange membrane solution is filtered through a 200-300 mesh filter membrane to remove undissolved substances, polymer particles, environmental dust, and other solid impurities that may be present in the solution, ensuring its purity. In practice, stainless steel or polyester fiber filter membranes can be used, and the solution is passed through the membrane via gravity or pressure filtration. Alternatively, microporous membranes with appropriate pore sizes, such as polypropylene (PP) or polytetrafluoroethylene (PTFE) membranes, can be used, employing vacuum filtration or pump filtration. Choosing a 200-300 mesh membrane effectively intercepts larger impurity particles while avoiding membrane clogging or a significant reduction in filtration efficiency due to excessively high filtration precision, thus ensuring the uniformity of subsequent coating.

[0065] Simultaneously, the ion-exchange membrane solution undergoes vacuum degassing at -0.08 MPa to -0.09 MPa. The purpose of this is to reduce the solubility of gases in the liquid using a negative pressure environment, promoting the escape of dissolved gases and suspended bubbles. This aims to remove microbubbles that may be introduced during stirring, preventing them from forming pores or defects during film formation, thus affecting the membrane's smoothness and performance. In practice, the container holding the ion-exchange membrane solution can be placed in a vacuum drying oven or vacuum chamber, and a vacuum pump can be used to evacuate the air, achieving a negative pressure of -0.08 MPa to -0.09 MPa inside the chamber. Alternatively, a stirred tank with a vacuum interface can be used, and the space inside the tank can be directly evacuated after stirring to achieve the required negative pressure conditions. The selection of a negative pressure range of -0.08 MPa to -0.09 MPa is optimized, effectively promoting the escape of bubbles from the ion-exchange membrane solution while avoiding excessive evaporation of volatile components due to excessively high vacuum, which could affect the component ratio and performance of the ion-exchange membrane solution.

[0066] In addition, the vacuum degassing time is set to 15 to 20 minutes to ensure that bubbles in the ion exchange membrane solution have sufficient time to escape completely, achieving a thorough degassing effect. The vacuum pump's operating time can be precisely controlled via a timer or automated control system, allowing it to run continuously for 15 to 20 minutes after reaching the set negative pressure. Alternatively, the escaping of bubbles from the ion exchange membrane solution surface can be observed; when surface bubbles significantly decrease or no longer escape in large quantities, the process can be maintained for a further period to ensure the removal of deep-seated bubbles, with the total duration controlled within 15 to 20 minutes. This time range ensures thorough bubble removal while maintaining production efficiency and avoiding unnecessary long processing times.

[0067] In this optional embodiment, the ion exchange membrane solution undergoes fine filtration and vacuum defoaming before coating, effectively removing solid impurities and microbubbles from the solution. Specifically, a 200-300 mesh filter membrane can precisely intercept various particulate impurities, preventing them from forming defect points or stress concentration areas during film formation. Simultaneously, vacuum defoaming for 15-20 minutes under a negative pressure of -0.08 MPa to -0.09 MPa efficiently and gently removes bubbles introduced during stirring from the ion exchange membrane solution. This synergistic effect ensures the high uniformity and purity of the ion exchange membrane solution, fundamentally eliminating the risks of uneven membrane surface, uneven shrinkage, and subsequent curling caused by impurities and bubbles. Ultimately, the prepared dielectric ion exchange membrane exhibits superior surface smoothness, more stable mechanical properties, and more reliable electrochemical performance, significantly improving the overall quality and application reliability of the membrane.

[0068] Optionally, S5 also includes the following steps: The dielectric ion membrane is heat-treated at 40°C to 50°C for 1 to 2 hours, and the ambient humidity is adjusted to 40% to 60% to make the water content of the dielectric ion membrane 10% to 15%.

[0069] Specifically, the dielectric ion exchange membrane is heat-treated at 40°C to 50°C for 1 to 2 hours. This heat treatment step aims to promote the uniform evaporation of residual moisture in the dielectric ion exchange membrane under mild heating conditions, while avoiding membrane deformation or degradation caused by high temperatures. Specifically, the heat treatment can be carried out in a convection oven with precise temperature control to ensure uniform heating of the membrane; alternatively, an infrared heating system can be used to achieve precise temperature control of the membrane surface and interior through non-contact heating, thereby effectively reducing shrinkage stress within the membrane; or, a vacuum oven can be used to treat the membrane within a specified temperature range to accelerate moisture removal.

[0070] Simultaneously, the ambient humidity is adjusted to 40% to 60%. This humidity adjustment aims to precisely control the rate of moisture evaporation during the membrane drying process, preventing excessively rapid moisture evaporation from causing uneven local shrinkage and subsequently membrane curling. Specifically, this can be achieved by placing the dielectric ion membrane in a constant temperature and humidity chamber with humidity control functionality; alternatively, a local humidity control system can be used, such as introducing precisely humidified airflow into the heat treatment area and combining it with a humidity sensor for real-time feedback adjustment to maintain the target humidity range; or, the ambient humidity can be precisely adjusted by controlling the dew point temperature of the drying gas (such as air or nitrogen).

[0071] Furthermore, the water content of the dielectric ion exchange membrane is maintained at 10% to 15%. This water content control target aims to ensure that the dielectric ion exchange membrane possesses appropriate flexibility and stability in its final state, balancing its mechanical and electrical properties to achieve optimal performance. Excessive water content may lead to membrane softening and structural instability, while excessively low water content may cause it to become brittle. To achieve this goal, the water content can be indirectly determined by monitoring the membrane's mass change in real time during heat treatment, stopping treatment when the mass reaches a preset range; alternatively, samples can be taken periodically, and the membrane's water content can be accurately measured using specialized equipment such as a Karl Fischer moisture analyzer or thermogravimetric analyzer. The heat treatment time and ambient humidity parameters can be adjusted based on the measurement results until the water content stabilizes within the 10% to 15% range; alternatively, the target water content can be indirectly achieved by controlling the heat treatment time and ambient humidity based on a pre-established drying curve.

[0072] In this optional embodiment, after the dielectric ion membrane is formed by UV curing, further heat treatment and humidity control of the membrane can effectively solve the problem of uneven shrinkage caused by moisture evaporation. Specifically, heat treatment at a mild temperature of 40°C to 50°C for 1 to 2 hours helps to uniformly evaporate residual moisture in the membrane, avoiding membrane deformation or degradation that may be caused by high temperatures, while ensuring slow evaporation of moisture, significantly reducing shrinkage stress inside the membrane. Furthermore, by adjusting the ambient humidity to 40% to 60%, the evaporation rate of moisture is further precisely controlled, effectively preventing localized uneven shrinkage caused by rapid drying, thereby ensuring uniform drying of the membrane as a whole. Finally, controlling the moisture content of the dielectric ion membrane within a specific range of 10% to 15% ensures that the membrane has suitable flexibility and stability, avoiding softening and deformation caused by excessive moisture content and embrittlement caused by excessive moisture content, thus achieving a good balance between mechanical properties and conductivity. These synergistic effects, after UV curing and shaping, further stabilize the film structure, significantly prevent film curling, and greatly improve the flatness, long-term stability, and application reliability of the dielectric ion membrane, making it more suitable for high-precision and long-term applications.

[0073] Another embodiment of the present invention provides an application of the dielectric ion membrane described above in the fields of electrochemical sensors and energy storage devices.

[0074] Specifically, dielectric double-layer ion membranes possess high dielectric constant, ionic conductivity, flexibility, and interfacial compatibility, and have become key functional materials in the three major fields of electrochemistry, sensors, and energy storage. The core is to achieve functional regulation by using the ion double-layer effect and selective ion transport.

[0075] The present invention will be further described below with reference to specific embodiments.

[0076] Example 1: Preparation of a dielectric ion membrane with UV crosslinking.

[0077] 1. Preparation of PVA solution PVA powder with a molecular weight Mw = 75000 was added to deionized water. The degree of polymerization of the PVA powder was approximately 1700. The mixture was stirred in a 90°C oil bath at 500 rpm for 3 hours until the PVA powder was completely dissolved, thus preparing a PVA aqueous solution with a mass fraction of 18 wt%. 2. Introduction of the ion system Add phosphoric acid to the PVA aqueous solution, controlling the mass fraction of phosphoric acid to 5 wt%, and stir for 30 minutes until homogeneous; 3. Introduction of photocurable groups Add polyethylene glycol diacrylate (PEGDA) to the mixed solution to make the PEGDA mass fraction in the solution 3.5 wt%, and stir for 30 min until homogeneous; 4. Photoinitiator Add photoinitiator 1173 (i.e., 2-hydroxy-2-methyl-1-phenyl-1-propanone) to the mixed solution in step 3, so that the mass fraction of photoinitiator 1173 in the solution is 0.5 wt%, stir evenly in the dark, and obtain the ion membrane solution; 5. Pretreatment of ion-exchange membrane solution The ion exchange membrane solution was filtered through a 250-mesh filter membrane and then defoamed under vacuum at -0.08 MPa for 15 minutes to remove impurities and air bubbles, ensuring the homogeneity of the ion exchange membrane solution. 6. Coating The ion exchange membrane solution was cast and uniformly coated onto the surface of an ethylene-tetrafluoroethylene (ETFE) substrate to a thickness of 0.5 mm. 7. Light curing The wet film coated in step 6 is subjected to ultraviolet light at a wavelength of 365 nm and an intensity of 100 mW / cm². 2 , irradiate for 2 minutes; 8. After photocuring, place it in a 50℃ oven for 2 hours for heat treatment, adjust the ambient humidity to 50%, maintain the water content of the dielectric ion membrane at 13%, optimize the mechanical properties and ionic conductivity of the dielectric ion membrane, and bring the dielectric ion membrane to its optimal state.

[0078] Photograph the dielectric layer ion membrane of the product, such as Figure 2 and Figure 3 As shown, the dielectric ion exchange film is flat and not curled. Surface roughness testing was performed on the dielectric ion exchange film of the product, and the test results are as follows. Figure 4As shown, the test range is 800~2400 μm, covering a relatively long surface length, and the results are statistically representative. X magnification: x100 (horizontal magnification), Z magnification: x100000 (vertical magnification, used to capture extremely fine surface undulations), and the average roughness Ra=0.046 μm is obtained, indicating that the surface of the dielectric ion film is generally ultra-smooth and highly precise.

[0079] A single-point capacitor was fabricated by encapsulating a dielectric ion-exchange film within a parallel plate electrode with a diameter of φ=5mm. Its electrical performance was then tested, and the results are as follows: Figure 5 As shown, the two fitted R values 2 All remain at R 2 =0.99, exhibiting excellent linear output characteristics.

[0080] Comparative Example 1: An ion exchange membrane without UV crosslinking was prepared.

[0081] 1. Preparation of PVA solution PVA powder with a molecular weight Mw = 75000 was added to deionized water. The degree of polymerization of the PVA powder was approximately 1700. The mixture was stirred in a 90°C oil bath at 500 rpm for 3 hours until the PVA powder was completely dissolved, thus preparing a PVA aqueous solution with a mass fraction of 18 wt%. 2. Introduction of the ion system Add phosphoric acid to the PVA aqueous solution, controlling the mass fraction of phosphoric acid to 5 wt%, and stir for 30 minutes until homogeneous; 3. Thermal crosslinking system Add gallium (Ga) to the mixed solution to make the mass fraction of gallium in the solution 1 wt%, and stir for 30 min until homogeneous; 4. Pretreatment of ionic solutions The mixture from step 3 was filtered through a 250-mesh filter membrane and then defoamed under vacuum at -0.08 MPa for 15 minutes to remove impurities and bubbles, ensuring the homogeneity of the ionic solution. 6. Coating The ionic solution was cast and uniformly coated onto the surface of an ethylene-tetrafluoroethylene (ETFE) substrate to a thickness of 0.5 mm. 7. Light curing Place the wet film coated in step 6 at room temperature for 2 hours, then heat-treat it in a 50°C oven for 4 hours.

[0082] Photograph the product ion exchange membrane, such as Figure 6 and Figure 7 As shown, the ion exchange membrane is uneven and curled. Surface roughness testing was performed on the product ion exchange membrane, and the results are as follows. Figure 8As shown, the test range is 800~2400 μm, covering a relatively long surface length, and the results are statistically representative. X magnification: x100 (horizontal magnification), Z magnification: x20000 (vertical magnification, used to capture extremely fine surface undulations), and the average roughness Ra=0.419 μm is obtained, indicating that the overall surface smoothness of the ion membrane is much lower than that of Example 1, and the surface of the ion membrane is curled and uneven.

[0083] An ion exchange membrane was encapsulated within a parallel plate electrode with a diameter of φ=5mm to create a single-point capacitor. Its electrical performance was then tested, and the results are as follows: Figure 9 As shown, the three segments exhibit a linear trend, with sensitivity gradually decreasing as pressure increases, indicating unstable electrical performance.

[0084] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A dielectric ion membrane, characterized in that, The invention includes a substrate and an ion exchange membrane coated on the surface of the substrate, wherein the ion exchange membrane comprises polyvinyl alcohol, an ion system, a UV-curable monomer, and a photoinitiator, and the ion exchange membrane is a cured film structure formed after being cured by ultraviolet light irradiation.

2. The dielectric ion membrane according to claim 1, characterized in that, The substrate is an ethylene-tetrafluoroethylene copolymer substrate.

3. The dielectric ion membrane according to claim 1, characterized in that, The ion exchange membrane comprises, by weight, 65 to 75 parts polyvinyl alcohol, 1 to 10 parts ion system, 1 to 5 parts UV-curable monomer and 0.1 to 1 part photoinitiator.

4. The dielectric ion membrane according to claim 1, characterized in that, The ionic system includes one or more of sodium chloride, potassium chloride, ammonium acetate, citric acid, acetic acid, and phosphoric acid.

5. The dielectric ion membrane according to claim 1, characterized in that, The UV-curable monomer includes one or more of methyl methacrylate and acrylate.

6. The dielectric ion membrane according to claim 1, characterized in that, The photoinitiator includes one or more of benzoyl peroxide and 2-hydroxy-2-methyl-1-phenyl-1-propanone.

7. A method for preparing a dielectric ion membrane as described in any one of claims 1-6, characterized in that, Includes the following steps: S1: Dissolve polyvinyl alcohol as the matrix in water to obtain a polyvinyl alcohol aqueous solution; S2: Add the ionic system to the polyvinyl alcohol aqueous solution and dissolve it to provide conductivity; S3: Add the UV-curable monomer to the polyvinyl alcohol aqueous solution and dissolve it; S4: Add the photoinitiator to the polyvinyl alcohol aqueous solution and stir to obtain an ion-exchange membrane solution; S5: The ion membrane solution is coated onto the surface of a substrate and cured by ultraviolet light irradiation to obtain a dielectric ion membrane, wherein the ultraviolet light irradiation wavelength is 365 nm and the intensity is 50 to 100 mW / cm². 2 The irradiation time is 2 to 5 minutes.

8. The method for preparing the dielectric ion membrane according to claim 7, characterized in that, In step S1, the polyvinyl alcohol is dissolved in water at 85°C to 95°C and stirred for 2 to 3 hours.

9. The method for preparing a dielectric ion membrane according to claim 7, characterized in that, S4 further includes the following steps: The ion-exchange membrane solution is filtered through a 200-300 mesh filter membrane and then subjected to vacuum degassing at -0.08 MPa to -0.09 MPa for 15 to 20 minutes. S5 further includes the following steps: The dielectric ion membrane is heat-treated at 40°C to 50°C for 1 to 2 hours, and the ambient humidity is adjusted to 40% to 60% to make the water content of the dielectric ion membrane 10% to 15%.

10. An application of the dielectric ion membrane as described in any one of claims 1-6 in the field of electrochemical sensors and energy storage devices.

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