PVDF (Polyvinylidene Fluoride) film with hydrophobicity and oleophobicity and preparation method thereof
By constructing mesoporous SiO2 nanoparticles with multi-level micro-nano structures on the surface of PVDF membranes and modifying them with perfluorosilanes, the problem of PVDF membranes easily adsorbing pollutants was solved, the hydrophobic and oleophobic properties were improved, and the maintenance costs were reduced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-16
- Publication Date
- 2026-04-28
AI Technical Summary
PVDF membranes are prone to absorbing dust and oil in outdoor environments, resulting in high maintenance costs, affecting service life and widespread application.
Multi-level micro-nano structured mesoporous SiO2 nanoparticles were constructed on the surface of a PVDF film, and low surface energy modification was performed using perfluorosilanes. Hydrophobic and oleophobic films were then prepared by combining PVDF with PMMA resin.
It significantly improves the hydrophobic and oleophobic properties of PVDF membranes, reduces pollutant adsorption, and lowers cleaning frequency and maintenance costs.
Smart Images
Figure CN121927464A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of PVDF membrane materials, specifically relating to a PVDF membrane that is both hydrophobic and oleophobic and its preparation method. Background Technology
[0002] With the increasing demands for weather resistance in modern buildings and outdoor facilities, traditional materials such as polyester (PET) and polyvinyl chloride (PVC) commonly suffer from problems such as powdering, fading, cracking, and peeling under long-term ultraviolet radiation, damp heat cycling, and chemical corrosion. This leads to deterioration in appearance and a decline in mechanical properties, which in turn affects the overall structural safety and service life.
[0003] Polyvinylidene fluoride (PVDF) resin, with its high C–F bond energy of 485 kJ / mol, exhibits excellent resistance to UV aging, chemical corrosion, and damp heat, making it an ideal matrix for high-end outdoor weather-resistant membrane materials. However, during long-term use in outdoor environments, the surface of PVDF outdoor membranes frequently adsorbs pollutants such as dust and oil, requiring frequent manual cleaning and resulting in high maintenance costs. In summary, the problem of PVDF membrane surface easily adsorbing pollutants seriously affects the long-term service cost and lifespan of PVDF membranes, hindering their further promotion and application.
[0004] Therefore, there is an urgent need to develop a PVDF membrane material that combines hydrophobic and oleophobic properties to avoid membrane surface fouling during long-term outdoor use, reduce the frequency of cleaning outdoor PVDF membranes, and lower maintenance costs. Thus, developing a PVDF membrane with both hydrophobic and oleophobic properties and its preparation method is of great significance for further promoting the application of PVDF membranes. Summary of the Invention
[0005] The purpose of this invention is to provide a PVDF membrane that is both hydrophobic and oleophobic, and its preparation method, in order to solve the problem that the surface of PVDF membranes in the prior art is prone to adsorbing dust and oil stains from the environment.
[0006] To achieve the above objectives, this invention discloses a method for preparing a PVDF membrane that possesses both hydrophobic and oleophobic properties. The specific plan is as follows: A PVDF outdoor membrane with both hydrophobic and oleophobic properties and its preparation method, comprising the following steps: S1. Place SiO2 nanoparticles in pure water at an addition rate of 10-200 g / L, and sonicate until uniformly dispersed to obtain a dispersion. S2. Add 0.1~0.3 mol / L hexadecyltrimethylammonium bromide to the dispersion in step S1, then add 0.5~0.8 mol / L Na2CO3, and sonicate for 12~24 h to obtain the reaction mixture; S3. The mixture from step S2 is centrifuged, then washed with ethanol and dried to obtain mesoporous SiO2 nanoparticles. S4. Prepare isopropanol solutions of perfluorosilane low surface energy substances with a concentration of 0.5g to 3g / L; S5. Add the mesoporous SiO2 nanoparticles to the isopropanol solution of perfluorosilane low surface energy material and stir at room temperature for 1-5 h to allow SiO2 to react fully with the perfluorosilane low surface energy material to obtain an isopropanol solution containing mesoporous SiO2 nanoparticles and perfluorosilane low surface energy material. S6. The isopropanol solution containing mesoporous SiO2 nanoparticles and perfluorosilane-based low surface energy substances from step S5 is filtered to obtain surface-modified mesoporous SiO2 nanoparticles. S7. Surface-modified mesoporous SiO2 nanoparticles are incorporated into PVDF resin and PMMA resin, and a PVDF film with both hydrophobic and oleophobic properties is prepared by casting extrusion process.
[0007] Preferably, in step S1, the particle size of the SiO2 nanoparticles is 20 ~ 400 nm.
[0008] Preferably, in step S4, the selected perfluorosilane low surface energy material includes one or more of perfluorohexyltrichlorosilane, perfluorooctyltrichlorosilane, and perfluorobutyltrichlorosilane.
[0009] Preferably, in step S7, the amount of surface-modified mesoporous SiO2 nanoparticles added is 3~15 wt%.
[0010] Preferably, in step S7, the proportions of each component added are: 80-90 parts of PVDF resin, 10-15 parts of PMMA resin, and 5-10 parts of surface-modified mesoporous SiO2 nanoparticles.
[0011] Preferably, in step S7, the casting extrusion process involves blending and granulating PVDF resin, PMMA resin, and surface-modified mesoporous SiO2 nanoparticles using a twin-screw granulator, and then casting the mixture into a PVDF film with a thickness of 20~80 μm using a single-screw extruder.
[0012] Based on the same inventive concept, the present invention also provides a PVDF membrane that is both hydrophobic and oleophobic, prepared according to the preparation method described above.
[0013] In summary, the beneficial effects of this invention are as follows: Mesoporous SiO2 nanoparticles were prepared, which constructed a multi-level micro / nano structure on the surface of the PVDF film. Compared to conventional SiO2 nanoparticles, the mesoporous SiO2 nanoparticles can construct a multi-level micro / nano structure on the PVDF film surface, further enhancing the hydrophobic and oleophobic properties of the PVDF film surface. Furthermore, this invention uses perfluorosilane-based low surface energy materials to modify the SiO2 nanoparticles, improving both the hydrophobic and oleophobic properties of the PVDF film product and strengthening the interfacial compatibility and dispersibility between the SiO2 inorganic particles and the organic resin. In addition, addressing the drawback of the time-consuming SiO2 modification process, this invention separates the SiO2 modification process from the PVDF resin film formation process, thus ensuring that the SiO2 modification process does not affect the continuous production process of PVDF resin extrusion molding. Attached Figure Description
[0014] Figure 1 This is a photograph of a PVDF membrane with both hydrophobic and oleophobic properties prepared by the method of the present invention. Detailed Implementation
[0015] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments, comparative examples and performance test results. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention. Example 1
[0016] A 10 g / L aqueous solution of SiO2 nanoparticles with a particle size of 20 nm was prepared. Hexadecyltrimethylammonium bromide (CTAB) was added to the solution to a molar concentration of 0.1 mol / L. Na2CO3 was added to the solution to a molar concentration of 0.5 mol / L. After sonication for 24 hours, the nanoparticles were centrifuged, washed with ethanol, and dried to obtain mesoporous SiO2 nanoparticles. A 0.5 g / L isopropanol (IPA) solution of perfluorooctyltrichlorosilane (PFOTS) was prepared. 10 g of the above mesoporous SiO2 nanoparticles were added to the PFOTS IPA solution and stirred at room temperature for 3 h. An IPA solution containing mesoporous SiO2 nanoparticles and PFOTS was subjected to solid-liquid separation by filtration to obtain low surface energy mesoporous SiO2 nanoparticles modified with PFOTS. The low surface energy mesoporous SiO2 nanoparticles were then incorporated into PVDF resin and PMMA resin in the following proportions: 90 parts PVDF resin, 10 parts PMMA resin, and 10 parts low surface energy mesoporous SiO2 nanoparticles. The above components were blended and granulated using a twin-screw extruder, and a PVDF film with both hydrophobic and oleophobic properties was prepared by a casting extrusion process, with a film thickness of 20 ± 1 μm.
[0017] Comparative Example 1-1 A 10 g / L aqueous solution of SiO2 nanoparticles with a particle size of 20 nm was prepared. CTAB was added to the solution to a molar concentration of 0.1 mol / L. Na2CO3 was added to the solution to a molar concentration of 0.5 mol / L. After sonication for 24 hours, the solution was centrifuged, washed with ethanol, and dried to obtain mesoporous SiO2 nanoparticles. The mesoporous SiO2 nanoparticles were then incorporated into PVDF and PMMA resins in the following proportions: 90 parts PVDF resin, 10 parts PMMA resin, and 10 parts mesoporous SiO2 nanoparticles. The mixture was granulated using a twin-screw extruder and then extruded to obtain a PVDF outdoor film with a thickness of 20 ± 1 μm.
[0018] Comparative Examples 1-2 A 0.5 g / L isopropanol (IPA) solution of perfluorooctyltrichlorosilane (PFOTS) was prepared. 10 g of SiO2 nanoparticles with a particle size of 20 nm were added to the PFOTS IPA solution and stirred at room temperature for 3 h. The IPA solution containing SiO2 nanoparticles and PFOTS was subjected to solid-liquid separation by filtration to obtain PFOTS-modified low surface energy SiO2 nanoparticles. The low surface energy SiO2 nanoparticles were incorporated into PVDF resin and PMMA resin in the following proportions: 90 parts PVDF resin, 10 parts PMMA resin, and 10 parts low surface energy SiO2 nanoparticles. The above components were blended and granulated using a twin-screw extruder, and a PVDF outdoor film with a thickness of 20 ± 1 μm was prepared by a casting extrusion process.
[0019] Comparative Examples 1-3 Ordinary SiO2 nanoparticles with a particle size of 20 nm were incorporated into PVDF resin and PMMA resin. The addition ratio of each component was: 90 parts of PVDF resin, 10 parts of PMMA resin, and 10 parts of SiO2 nanoparticles. The above components were blended and granulated by a twin-screw extruder, and a PVDF outdoor film with a film thickness of 20 ± 1 μm was prepared by a casting extrusion process. Example 2
[0020] Prepare a 20 g / L aqueous solution of SiO2 nanoparticles with a particle size of 220 nm; add hexadecyltrimethylammonium bromide (CTAB) to the solution to a molar concentration of 0.3 mol / L; add Na2CO3 to the solution to a molar concentration of 0.8 mol / L; sonicate for 18 hours, then centrifuge, wash with ethanol, and dry to obtain mesoporous SiO2 nanoparticles; prepare a 3 g / L isopropanol (IPA) solution of perfluorohexyltrichlorosilane (PFFTS); add 25 g of the above mesoporous SiO2 nanoparticles to the PFFTS IPA solution and stir at room temperature for 1 hour. h; The IPA solution containing mesoporous SiO2 nanoparticles and PFFTS was subjected to solid-liquid separation by filtration to obtain low surface energy mesoporous SiO2 nanoparticles modified with PFFTS; The low surface energy mesoporous SiO2 nanoparticles were incorporated into PVDF resin and PMMA resin, with the following addition ratio: 85 parts of PVDF resin, 15 parts of PMMA resin, and 5 parts of low surface energy mesoporous SiO2 nanoparticles; The above components were blended and granulated by a twin-screw extruder, and a PVDF film with both hydrophobicity and oleophobicity was prepared by a casting extrusion process, with a film thickness of 30 ± 1 μm.
[0021] Comparative Example 2-1 A 20 g / L aqueous solution of SiO2 nanoparticles with a particle size of 220 nm was prepared. CTAB was added to the solution to a molar concentration of 0.3 mol / L. Na2CO3 was added to the solution to a molar concentration of 0.8 mol / L. After sonication for 18 hours, the solution was centrifuged, washed with ethanol, and dried to obtain mesoporous SiO2 nanoparticles. The mesoporous SiO2 nanoparticles were then incorporated into PVDF and PMMA resins in the following proportions: 85 parts PVDF resin, 15 parts PMMA resin, and 5 parts mesoporous SiO2 nanoparticles. The mixture was granulated using a twin-screw extruder and then extruded to obtain a PVDF outdoor film with a thickness of 30 ± 1 μm.
[0022] Comparative Example 2-2 A 3 g / L isopropanol (IPA) solution of perfluorohexyltrichlorosilane (PFFTS) was prepared. 25 g of SiO2 nanoparticles with a particle size of 220 nm were added to the PFFTS IPA solution and stirred at room temperature for 1 h. The IPA solution containing SiO2 nanoparticles and PFFTS was subjected to solid-liquid separation by filtration to obtain PFFTS-modified low surface energy SiO2 nanoparticles. The low surface energy SiO2 nanoparticles were incorporated into PVDF resin and PMMA resin, with the following proportions: 85 parts PVDF resin, 15 parts PMMA resin, and 5 parts low surface energy SiO2 nanoparticles. The above components were blended and granulated using a twin-screw extruder, and a PVDF outdoor film with a thickness of 30 ± 1 μm was prepared by a casting extrusion process.
[0023] Comparative Examples 2-3 Ordinary SiO2 nanoparticles with a particle size of 220 nm were incorporated into PVDF resin and PMMA resin. The addition ratio of each component was: 85 parts of PVDF resin, 15 parts of PMMA resin, and 5 parts of SiO2 nanoparticles. The above components were blended and granulated by a twin-screw extruder, and a PVDF outdoor film with a film thickness of 30 ± 1 μm was prepared by a casting extrusion process. Example 3
[0024] Prepare an aqueous solution of 200 g / L SiO2 nanoparticles with a particle size of 400 nm; add hexadecyltrimethylammonium bromide (CTAB) to the solution to a molar concentration of 0.2 mol / L; add Na2CO3 to the solution to a molar concentration of 0.7 mol / L; after sonication for 12 hours, centrifuge, wash with ethanol, and dry to obtain mesoporous SiO2 nanoparticles; prepare a 2 g / L isopropanol (IPA) solution of perfluorobutyltrichlorosilane; add 25 g of the above mesoporous SiO2 nanoparticles to the PFFTS IPA solution and stir at room temperature for 5 minutes. h; The IPA solution containing mesoporous SiO2 nanoparticles and PFFTS was subjected to solid-liquid separation by filtration to obtain low surface energy mesoporous SiO2 nanoparticles modified with PFFTS; The low surface energy mesoporous SiO2 nanoparticles were incorporated into PVDF resin and PMMA resin, with the following addition ratio: 80 parts of PVDF resin, 12 parts of PMMA resin, and 7 parts of low surface energy mesoporous SiO2 nanoparticles; The above components were blended and granulated by a twin-screw extruder, and a PVDF film with both hydrophobicity and oleophobicity was prepared by a casting extrusion process, with a film thickness of 80 ± 1 μm.
[0025] Comparative Example 3-1 A 200 g / L aqueous solution of SiO2 nanoparticles with a particle size of 400 nm was prepared. CTAB was added to the solution to a molar concentration of 0.2 mol / L. Na2CO3 was added to the solution to a molar concentration of 0.7 mol / L. After sonication for 12 hours, the solution was centrifuged, washed with ethanol, and dried to obtain mesoporous SiO2 nanoparticles. The mesoporous SiO2 nanoparticles were then incorporated into PVDF and PMMA resins in the following proportions: 80 parts PVDF resin, 12 parts PMMA resin, and 7 parts mesoporous SiO2 nanoparticles. The mixture was granulated using a twin-screw extruder and then extruded to obtain a PVDF outdoor film with a thickness of 80 ± 1 μm.
[0026] Comparative Example 3-2 A 2 g / L isopropanol (IPA) solution of perfluorobutyltrichlorosilane was prepared. 25 g of SiO2 nanoparticles with a particle size of 400 nm were added to the PFFTS IPA solution and stirred at room temperature for 5 h. The IPA solution containing SiO2 nanoparticles and PFFTS was subjected to solid-liquid separation by filtration to obtain PFFTS-modified low surface energy SiO2 nanoparticles. The low surface energy SiO2 nanoparticles were incorporated into PVDF resin and PMMA resin in the following proportions: 80 parts PVDF resin, 12 parts PMMA resin, and 7 parts low surface energy SiO2 nanoparticles. The above components were blended and granulated using a twin-screw extruder, and a PVDF outdoor film with a thickness of 80 ± 1 μm was prepared by a casting extrusion process.
[0027] Comparative Example 3-3 Ordinary SiO2 nanoparticles with a particle size of 400 nm were incorporated into PVDF resin and PMMA resin. The addition ratio of each component was: 80 parts of PVDF resin, 12 parts of PMMA resin, and 7 parts of SiO2 nanoparticles. The above components were blended and granulated by a twin-screw extruder, and a PVDF outdoor film with a film thickness of 80 ± 1 μm was prepared by a casting extrusion process.
[0028] Performance testing The hydrophobicity and oleophobicity of the prepared PVDF film were tested: Table 1. Contact angles of water and n-hexadecane in each embodiment and comparative example
[0029] As shown in Table 1, chemically grafting low-surface-energy perfluorosilanes onto the surface of SiO2 nanoparticles to prepare PVDF outdoor films significantly improves the hydrophobic and oleophobic properties of the film surface, reducing the risk of contaminant adsorption on the film surface. Furthermore, using mesoporous SiO2 nanoparticles can further enhance the hydrophobic and oleophobic properties of the prepared PVDF film surface.
[0030] This invention discloses and proposes a PVDF membrane with both hydrophobic and oleophobic properties and its preparation method. Although the content of this invention has been specifically described through examples, those skilled in the art can obviously modify or recombine the methods and technical routes described herein without departing from the content, spirit, and scope of this invention to achieve the final preparation technology. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included within the spirit, scope, and content of this invention.
Claims
1. A method for preparing a PVDF membrane with both hydrophobic and oleophobic properties, characterized in that, Includes the following steps: S1. Place SiO2 nanoparticles in pure water at an addition rate of 10-200 g / L, and sonicate until uniformly dispersed to obtain a dispersion. S2. Add 0.1~0.3mol / L hexadecyltrimethylammonium bromide to the dispersion in step S1, then add 0.5~0.8mol / L Na2CO3, and sonicate for 12~24 h to obtain the reaction mixture; S3. The mixture from step S2 is centrifuged, then rinsed with ethanol and dried to obtain mesoporous SiO2 nanoparticles. S4. Prepare an isopropanol solution of perfluorosilane low surface energy substances with a concentration of 0.5g to 3g / L; S5. Add the mesoporous SiO2 nanoparticles to the isopropanol solution of perfluorosilane low surface energy material and stir at room temperature for 1-5 h to allow SiO2 to react fully with the perfluorosilane low surface energy material to obtain an isopropanol solution containing mesoporous SiO2 nanoparticles and perfluorosilane low surface energy material. S6. The isopropanol solution containing mesoporous SiO2 nanoparticles and perfluorosilane-based low surface energy substances from step S5 is filtered to obtain surface-modified mesoporous SiO2 nanoparticles. S7. Surface-modified mesoporous SiO2 nanoparticles are incorporated into PVDF resin and PMMA resin, and a PVDF film with both hydrophobic and oleophobic properties is prepared by casting extrusion process.
2. The method for preparing a PVDF membrane with both hydrophobic and oleophobic properties according to claim 1, characterized in that, In step S1, the particle size of the SiO2 nanoparticles is 20 ~ 400 nm.
3. The method for preparing a PVDF membrane with both hydrophobic and oleophobic properties according to claim 1, characterized in that, In step S4, the selected perfluorosilane low surface energy material includes one or more of perfluorohexyltrichlorosilane, perfluorooctyltrichlorosilane, and perfluorobutyltrichlorosilane.
4. The method for preparing a PVDF membrane with both hydrophobic and oleophobic properties according to claim 1, characterized in that, In step S7, the proportions of each component added are as follows: 80-90 parts of PVDF resin, 10-15 parts of PMMA resin, and 5-10 parts of surface-modified mesoporous SiO2 nanoparticles.
5. The method for preparing a PVDF membrane with both hydrophobic and oleophobic properties according to claim 1, characterized in that, In step S7, the casting extrusion process involves blending and granulating PVDF resin, PMMA resin, and surface-modified mesoporous SiO2 nanoparticles using a twin-screw granulator, and then casting the mixture into a PVDF film with a thickness of 20~80μm using a single-screw extruder.
6. A PVDF membrane possessing both hydrophobic and oleophobic properties, characterized in that, It is prepared by the method for preparing a PVDF membrane with both hydrophobic and oleophobic properties as described in any one of claims 1 to 5.