A transparent hydrophilic film with photo-thermal anti-fogging and defogging performance and a preparation method thereof

Abstract

The present application belongs to the technical field of photo-thermal hydrophilic film, and discloses a transparent hydrophilic film with photo-thermal anti-fog and defogging performance and a preparation method thereof. The transparent hydrophilic film is obtained by film forming treatment of a composite film solution, and the composite film solution comprises polyvinyl alcohol, sulfonic acid-based polymer, cesium tungsten bronze nanoparticles and deionized water. The polyvinyl alcohol is dissolved in deionized water, a hydrophilic crosslinking network is constructed through hydrogen bond interaction between the polyvinyl alcohol and the sulfonic acid-based polymer material, and the transparent photo-thermal hydrophilic anti-fog film is prepared in cooperation with the cesium tungsten bronze nanoparticles. The anti-fog film material prepared by the present application introduces a twisted non-planar structure to increase the molecular free volume and thus improve the moisture absorption capacity of the film, while maintaining high transparency, and has excellent photo-thermal performance in the ultraviolet / near-infrared region of sunlight, and under the irradiation of a strong sunlight, the anti-fog and defogging effects are achieved.

Description

Technical Field

[0001] This invention belongs to the field of photothermal hydrophilic film technology, and relates to a transparent hydrophilic film with photothermal anti-fogging and defogging properties and its preparation method. Background Technology

[0002] Surface fogging is a common phenomenon that occurs near or below the atmospheric dew point, caused by the condensation of water vapor into tiny water droplets. These droplets cause multiple refractions of light, resulting in severe blurred vision and reduced optical transparency, seriously affecting surfaces such as windows, windshields, and eyeglasses.

[0003] To mitigate the risks associated with fogging, the most advanced methods currently employed primarily involve altering surface wettability to modify the interaction between the surface and water droplets. Creating hydrophobic surfaces with low wettability enhances the repulsive force between water droplets and the substrate, but it can only effectively remove droplets larger than the critical size (>10 μm) by gravity. Although the induced anti-fogging period may be very short, it is still unavoidable. Conversely, creating hydrophilic surfaces with high wettability promotes the rapid diffusion of condensed water droplets into a uniform water film, absorbing moisture through volume expansion. However, maintaining transparency and stability during repeated drying-expansion cycles is challenging. Even without the anti-fogging induction period, factors such as gravity, motion, and contaminants can damage the water film, leading to severe image distortion. To meet practical application requirements, the key challenge lies in the stability and tuning of the microstructure. Qiu Dong's paper, "Effective Antifogging Coating from Hydrophilic / Hydrophobic Polymer Heteronetwork" (Advanced Science 2022, 9, 2200072), improves interfacial stability by combining hydrophilic / hydrophobic heterostructures, but the preparation method is relatively complex and the compatibility of hydrophilic / hydrophobic components must be carefully considered.

[0004] Active antifogging technology, which converts light energy into heat energy, is considered a suitable solution. Compared with traditional methods such as electric heating, this technology has low operating costs, no chemical pollution, and is highly consistent with sustainable development goals. However, the manufacturing process of photothermal films is complex, and high-performance films are usually dark in color, which greatly reduces transparency. Most importantly, this technology is highly dependent on environmental conditions; the antifogging effect may weaken or even disappear on cloudy days or at night. Therefore, current reports such as "Transparent sunlight-activated antifogging metamaterials" (Nature Nanotechnology 2023, 18:137-144) and "Transparent selective photothermal coatings for antifogging applications" (Cell Reports Physical Science 2021, 2, 100435) cannot guarantee long-term stable antifogging performance. Summary of the Invention

[0005] The purpose of this invention is to overcome the limitations of existing hydrophilic / hydrophobic surfaces and the effectiveness of electric heating in preventing fogging, and to provide a transparent hydrophilic film with photothermal anti-fogging properties that combines active and passive methods, as well as its preparation method.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] In one aspect, the present invention provides a transparent hydrophilic film with photothermal anti-fogging and defogging properties, wherein the transparent hydrophilic film is obtained by film formation treatment of a composite film solution.

[0008] The composite film solution comprises polyvinyl alcohol, sulfonic acid polymer, cesium tungsten bronze nanoparticles, and deionized water, with the following mass percentages of each component:

[0009] Polyvinyl alcohol: sulfonic acid polymer: cesium tungsten bronze nanoparticles: deionized water = 1: 0.05~0.2: 0.005~0.02: 10~40.

[0010] The sulfonate polymer is a sulfonated polyarylene ether with a degree of sulfonation (DS) of 1.0–2.0. The sulfonated polyarylene ether includes one of sulfonated polyarylene ether sulfone, sulfonated polyarylene ether ketone, and sulfonated heteronaphthyl biphenyl polyarylene ether, and their specific structures are as follows:

[0011] The structural formula of sulfonated polyarylether sulfone is:

[0012]

[0013] The structural formula of sulfonated polyaryletherketone is:

[0014] The basic structural formula of sulfonated naphthalene-biphenyl polyarylether is:

[0015] in:

[0016] Ar1 and Ar3 are the main structures of dihalogenated monomers. Ar1 and Ar3 may be the same or different, and can be any one or more of the following structures:

[0017]

[0018] Ar2 is the main structure of the bisphenol monomer, and it is any one or more of the following structures:

[0019]

[0020] R1, R3, and R4 are hydrogen, halogen substituents, phenyl, phenoxy, straight-chain alkyl containing at least one carbon atom, branched alkyl containing at least one carbon atom, or branched alkoxy containing at least one carbon atom. R1, R3, and R4 may have the same or different structures, and R2 is a sulfonic acid group.

[0021] The sulfonated polyarylene ether is preferably a sulfonated heteronaphthyl biphenyl polyarylene ether, including one or more of sulfonated heteronaphthyl biphenyl polyarylene ether sulfone, sulfonated heteronaphthyl biphenyl polyarylene ether ketone, sulfonated heteronaphthyl biphenyl polyarylene ether sulfone ketone, and sulfonated heteronaphthyl biphenyl polyarylene ether nitrile ketone.

[0022] Another aspect of the present invention provides a method for preparing the above-mentioned transparent hydrophilic film, the method comprising the following steps:

[0023] Step 1: Dissolve polyvinyl alcohol in deionized water, then add sulfonic acid polymer, stir and mix, then add cesium tungsten bronze nanoparticle dispersion, stir and mix to obtain composite film solution.

[0024] Step 2: The composite film solution from Step 1 is deposited on the substrate surface to obtain a transparent hydrophilic film.

[0025] Furthermore, the film-forming method includes one or more of spraying, scraping, and dip-coating methods.

[0026] Furthermore, the substrate is a flexible substrate or a rigid substrate.

[0027] The innovation of this invention lies in its use of sulfonic acid polymers to construct a hydrophilic cross-linked network through hydrogen bonding interactions between sulfonic acid groups and hydroxyl groups. Specifically, the unique twisted non-coplanar structure of the phenazine biphenyl polyaryl ether material significantly enhances interfacial stability and increases molecular free volume, thereby greatly improving its hygroscopic capacity and extending its anti-fogging time. Furthermore, the photothermal synergy between the phenazine biphenyl polyaryl ether material and cesium tungsten bronze nanoparticles not only achieves high transparency but also enables efficient absorption of sunlight in the ultraviolet / near-infrared region. This invention effectively improves long-term stable anti-fogging and defogging effects through a strategy combining active photothermal activity and passive hydrophilicity.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) This invention uses sulfonic acid polymers and utilizes the hydrogen bonding between sulfonic acid groups and hydroxyl groups in polymer segments with different structures to prepare hydrophilic antifog films, thereby enhancing the strength and stability of the films based on existing antifog films. In particular, the sulfonated naphthalene biphenyl polyarylene ether material has a twisted non-coplanar structure, which can increase the free volume of molecules inside the film without changing the film thickness, thereby achieving a stable antifog effect.

[0030] (2) Based on the existing anti-fog hydrophilic film, the present invention also has photothermal active anti-fog capability. While maintaining the high transparency of the film, it utilizes the photothermal synergy between sulfonated naphthalene biphenyl polyarylene ether material and cesium tungsten bronze nanoparticles to have excellent absorption capacity in the ultraviolet and near-infrared regions of sunlight. It can convert solar energy into heat energy, increase the surface temperature and achieve long-term effective defogging and anti-fogging. At the same time, the active defogging capability of the present invention has low environmental dependence and still has a good defogging effect on cloudy days or at night, which has great potential application value.

[0031] (3) The photothermal hydrophilic film prepared by the present invention combines active and passive methods and can be prepared by various methods such as spraying, scraping and dipping. The process is simple and convenient to operate, suitable for large-scale construction and easy to apply to different object surfaces. Attached Figure Description

[0032] Figure 1 This is a surface morphology diagram of the thin film in Example 1.

[0033] Figure 2 This is a comparison diagram of the anti-fog effect of the anti-fog films prepared in Example 1 and Comparative Examples 1, 2, and 3 in high-temperature steam.

[0034] Figure 3 The images show the ultraviolet-visible-near-infrared absorption spectra of the antifog films prepared in Example 1 and Comparative Examples 1, 2, and 3. Detailed Implementation

[0035] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and technical solutions.

[0036] Example 1

[0037] This embodiment provides a transparent hydrophilic film with photothermal anti-fogging and defogging properties. The transparent hydrophilic film is obtained by film formation treatment of a composite film solution.

[0038] The composite film solution comprises polyvinyl alcohol, sulfonic acid polymer, cesium tungsten bronze nanoparticles, and deionized water, with the following mass percentages of each component:

[0039] Polyvinyl alcohol: sulfonic acid polymer: cesium tungsten bronze nanoparticles: deionized water = 1:0.1:0.005:10.

[0040] The sulfonate polymer is a sulfonated heteronaphthyl biphenyl polyarylene ether with a sulfonation degree (DS) of 1.0. The sulfonated heteronaphthyl biphenyl polyarylene ether includes one or more of the following: sulfonated heteronaphthyl biphenyl polyarylene ether sulfone, sulfonated heteronaphthyl biphenyl polyarylene ether ketone, sulfonated heteronaphthyl biphenyl polyarylene ether sulfone ketone, and sulfonated heteronaphthyl biphenyl polyarylene ether nitrile ketone. In this embodiment, sulfonated heteronaphthyl biphenyl polyarylene ether sulfone ketone is selected, and its basic structure is as follows:

[0041] in:

[0042] Ar1 and Ar3 are the main structures of dihalogenated monomers. Ar1 and Ar3 may be the same or different, and can be any one or more of the following structures:

[0043] In this embodiment, the Ar1 structure is as follows: The Ar3 structure is as follows:

[0044] Ar2 is the main structure of the bisphenol monomer, and it is any one or more of the following structures:

[0045] In this embodiment, the Ar2 structure is as follows:

[0046]

[0047] R1, R3, and R4 are hydrogen, halogen substituents, phenyl, phenoxy, straight-chain alkyl containing at least one carbon atom, branched alkyl containing at least one carbon atom, or branched alkoxy containing at least one carbon atom. R1, R3, and R4 may have the same or different structures, and R2 is a sulfonic acid group. In this embodiment, R1, R3, and R4 are all hydrogen.

[0048] The method for preparing the above-mentioned transparent hydrophilic film includes the following steps:

[0049] (1) Dissolve 5g of polyvinyl alcohol in 100mL of deionized water and stir in a water bath at 90℃ for 30min to obtain a polyvinyl alcohol solution. Then add 0.5g of sulfonated naphthalene biphenyl polyarylene sulfone ketone to the polyvinyl alcohol solution. After stirring at room temperature for 1h, add a dispersion containing 0.025g of cesium tungsten bronze nanoparticles obtained by ultrasonic treatment. Stir continuously with magnetic force at room temperature for 1h to obtain a composite film solution.

[0050] (2) The composite film solution in step (1) is used to prepare a transparent hydrophilic film by dip-coating method: the substrate is vertically immersed in the composite film solution at a constant speed of 0.5 cm / s and submerged for 10 min; then, the substrate is vertically lifted out of the solution at a constant speed of 0.1 cm / s and dried at room temperature for 12 h to evaporate the solvent and form a transparent hydrophilic film with a thickness of 25 μm. The substrate is selected from optical glass plate, PET flexible plastic or eyeglass lens. In this embodiment, optical glass plate is selected.

[0051] The transparent hydrophilic film prepared in this embodiment has a smooth surface, and the nanoparticles are well dispersed within the film. Figure 1 As shown.

[0052] Example 2

[0053] This embodiment provides a transparent hydrophilic film with photothermal anti-fogging and defogging properties. The transparent hydrophilic film is obtained by film formation treatment of a composite film solution.

[0054] The composite film solution comprises polyvinyl alcohol, sulfonic acid polymer, cesium tungsten bronze nanoparticles, and deionized water, with the following mass percentages of each component:

[0055] Polyvinyl alcohol: sulfonic acid polymer: cesium tungsten bronze nanoparticles: deionized water = 1:0.05:0.01:20.

[0056] The sulfonate polymer is a sulfonated polyarylene ether sulfone with a degree of sulfonation (DS) of 1.5, and its structural formula is:

[0057]

[0058] The structural formula used in this embodiment is:

[0059]

[0060] The method for preparing the above-mentioned transparent hydrophilic film includes the following steps:

[0061] (1) Dissolve 5g of polyvinyl alcohol in 100mL of deionized water and stir in a water bath at 90℃ for 30min to obtain a polyvinyl alcohol solution. Then add 0.25g of sulfonated polyarylether sulfone to the polyvinyl alcohol solution and stir at room temperature for 1h to obtain a polyvinyl alcohol / sulfonic acid polymer solution. Add a dispersion containing 0.05g of cesium tungsten bronze nanoparticles obtained by ultrasonic treatment and stir continuously with magnetic force at room temperature for 1h to obtain a composite film solution.

[0062] (2) Prepare a transparent hydrophilic film by spraying the composite film solution in step (1): Use a spin coater to uniformly coat the composite film solution onto the substrate at a speed of 2000-4000 rpm for 100-200 s, and then dry it at room temperature for 12-24 h to obtain a transparent hydrophilic film; In this embodiment, the substrate is a spectacle lens, the preferred spin coating speed is 4000 rpm, the preferred coating time is 100 s, and the preferred drying time is 12 h.

[0063] Example 3

[0064] This embodiment provides a transparent hydrophilic film with photothermal anti-fogging and defogging properties. The transparent hydrophilic film is obtained by film formation treatment of a composite film solution.

[0065] The composite film solution comprises polyvinyl alcohol, sulfonic acid polymer, cesium tungsten bronze nanoparticles, and deionized water, with the following mass percentages of each component:

[0066] Polyvinyl alcohol: sulfonic acid polymer: cesium tungsten bronze nanoparticles: deionized water = 1:0.2:0.02:40.

[0067] The sulfonate polymer is a sulfonated polyaryletherketone with a degree of sulfonation (DS) of 2.0, and its structural formula is:

[0068]

[0069] The method for preparing the above-mentioned transparent hydrophilic film includes the following steps:

[0070] (1) Dissolve 5g of polyvinyl alcohol in 100mL of deionized water and stir in a water bath at 90℃ for 30min to obtain a polyvinyl alcohol solution. Then add 1g of sulfonated polyarylether sulfone to the polyvinyl alcohol solution and stir at room temperature for 1h. Then add a dispersion containing 0.1g of cesium tungsten bronze nanoparticles obtained by ultrasonic treatment and stir continuously at room temperature for 1h to obtain a composite film solution.

[0071] (2) Prepare a transparent hydrophilic film by coating the composite film solution in step (1): Pour the composite film solution onto the substrate and coat it with a 200-800 μm blade. Then place it on a heating platform at 50-80°C to evaporate the solvent and form a transparent hydrophilic film. In this embodiment, the substrate is PET flexible plastic, the blade is preferably 600 μm, and the heating platform temperature is preferably 60°C.

[0072] Comparative Example 1

[0073] Comparative Example 1 is a polyvinyl alcohol film, which was prepared using a preparation process that is basically the same as that in Example 1. The difference is that the polyvinyl alcohol solution obtained in step (1) was used as the composite film solution and was used to prepare the polyvinyl alcohol film in step (2).

[0074] Comparative Example 2

[0075] Comparative Example 2 is a polyvinyl alcohol / poly(2-acrylamide-2-methyl-1-propanesulfonic acid) film, which was prepared using a preparation process that is basically the same as that in Example 1. The difference is that 0.5 g of poly(2-acrylamide-2-methyl-1-propanesulfonic acid) was added to the polyvinyl alcohol solution obtained in step (1), and the mixture was stirred at room temperature for 1 h to obtain a composite film solution, which was used to prepare the polyvinyl alcohol / poly(2-acrylamide-2-methyl-1-propanesulfonic acid) film in step (2).

[0076] Comparative Example 3

[0077] Comparative Example 3 is a polyvinyl alcohol / sulfonated heteronaphthyl biphenyl polyarylene sulfone ketone film, which was prepared using a preparation process that is basically the same as that in Example 1. The difference is that the polyvinyl alcohol / sulfonic acid polymer solution obtained in step (1) is used as the composite film solution and is used to prepare the polyvinyl alcohol / sulfonated heteronaphthyl biphenyl polyarylene sulfone ketone film in step (2).

[0078] See Figure 2 The image shows a comparison of the anti-fogging effects of the films prepared in Example 1 and Comparative Examples 1, 2, and 3 in high-temperature steam (5 cm above 100°C water). It was found that the anti-fogging time of Comparative Example 3 and Example 1 was significantly increased compared with Comparative Examples 1 and 2. Even though the transparency decreased after 30 minutes, it still maintained excellent interfacial stability. This is because the addition of the unique twisted non-coplanar structure of sulfonated naphthalene biphenyl polyaryl ether not only greatly improves the interfacial stability, but also increases the molecular free volume without changing the film thickness, thereby improving the moisture absorption capacity inside the film.

[0079] See Figure 3The images show the UV-Vis-NIR absorption spectra of the films prepared in Example 1 and Comparative Examples 1, 2, and 3. As can be seen from the figures, Example 1 exhibits excellent absorption performance in the UV and NIR regions of the solar spectrum, while maintaining high transparency in the visible light region. Comparative Examples 1-3, on the other hand, show poor absorption performance in the UV and NIR regions. This is because the sulfonated naphthalene-biphenyl polyarylene ether and the cesium tungsten bronze nanoparticles form a synergistic photothermal system, which possesses excellent absorption performance in the UV and NIR regions of the solar spectrum. This allows the surface temperature of the film to reach 57°C under sunlight irradiation, resulting in excellent photothermal defogging performance; water mist on the film surface can be completely removed within 2 minutes.

Claims

1. A transparent, hydrophilic film having photo-thermal anti-fogging and de-fogging properties, characterized in that, The transparent hydrophilic film is obtained by film forming treatment of a composite film solution. The composite film solution comprises polyvinyl alcohol, sulfonic acid-based polymer, cesium tungsten bronze nanoparticles and deionized water, and the mass percentage of each component is as follows: Polyvinyl alcohol: sulfonic acid-based polymer: cesium tungsten bronze nanoparticles: deionized water = 1: 0.05-0.2: 0.005-0.02: 10-40; The sulfonic acid-based polymer is sulfonated heteronaphthalene biphenyl polyarylether, and the sulfonation degree DS is 1.0-2.

0. The basic structural formula of the sulfonated heteronaphthalene biphenyl polyarylether is: wherein: Ar1 and Ar3 are the main structures of the dihalogen monomer, and Ar1 and Ar3 are the same or different, being any one or several of the following structures: ； Ar2 is the main structure of the bisphenol monomer, being any one or several of the following structures: ； R1, R3 and R4 are hydrogen, halogen substituent, phenyl, phenoxy, straight-chain alkyl containing at least 1 carbon atom, branched-chain alkyl containing at least 1 carbon atom or branched-chain alkoxy containing at least 1 carbon atom, and R1, R3 and R4 are the same or different in structure, and R2 is a sulfonic acid group.

2. The transparent hydrophilic film with photo-thermal anti-fog and de-fogging performance according to claim 1, characterized in that, The sulfonated polyarylether is sulfonated heteronaphthalene biphenyl polyarylether, including one or more of sulfonated heteronaphthalene biphenyl polyarylether sulfone, sulfonated heteronaphthalene biphenyl polyarylether ketone, sulfonated heteronaphthalene biphenyl polyarylether sulfone ketone, and sulfonated heteronaphthalene biphenyl polyarylether nitrile ketone.

3. A preparation method of the transparent hydrophilic film with light-heat anti-fogging performance according to any one of claims 1-2, the preparation method comprising the following steps: Step 1: dissolving polyvinyl alcohol in deionized water, then adding sulfonic acid-based polymer, stirring and mixing, and then adding cesium tungsten bronze nanoparticle dispersion, stirring and mixing to obtain a composite film solution; Step 2: forming a film of the composite film solution in step 1 on the surface of a substrate to obtain a transparent hydrophilic film.

4. The preparation method of the transparent hydrophilic film with light-heat anti-fogging performance according to claim 3, wherein the film forming method comprises one or more of spraying, blade coating and dip-coating.

5. The preparation method of the transparent hydrophilic film with light-heat anti-fogging performance according to claim 3, wherein the substrate is a flexible substrate or a hard substrate.

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