A method for preparing a polyvinyl alcohol composite hydrogel coating

Abstract

The application relates to a preparation method of a polyvinyl alcohol composite hydrogel coating and belongs to the field of coating preparation. The polyvinyl alcohol-silicon dioxide composite hydrogel coating is prepared on the surface of a substrate by coating technology and crosslinking treatment, with polyvinyl alcohol, an organic silicon source and polydopamine as main raw materials. The organic silicon source is fully hydrolyzed to obtain uniform silicon dioxide sol; the silicon dioxide sol is mixed with a polyvinyl alcohol solution to obtain a polyvinyl alcohol-silicon dioxide composite sol; the composite sol is uniformly coated on the surface of the substrate which has been modified by polydopamine; and the composite sol on the surface of the substrate is crosslinked to obtain the polyvinyl alcohol-silicon dioxide composite hydrogel coating. The obtained coating has a smooth surface and uniform microstructure, the required equipment is simple, the operation is convenient, the energy consumption and cost are low, the coating is environment-friendly and easy to be industrially produced. The coating can be used in the fields of biomedicine, crop planting, sewage treatment, cosmetics and the like.

Description

Technical Field

[0001] This invention relates to the field of coating preparation, and specifically to a method for preparing a polyvinyl alcohol composite hydrogel coating. Background Technology

[0002] Hydrogels are gel materials with a three-dimensional network structure formed by the swelling of polymers through water absorption. These materials possess unique advantages such as high swelling and water retention, good flexibility, and adhesion, making them widely used in wastewater treatment, crop cultivation, anti-marine organism adhesion, cosmetics, and many other fields. Furthermore, hydrogel materials exhibit good hydrophilicity, lubricity, and biocompatibility, which opens up possibilities for their application in biomedicine, healthcare, and personal care. For example, encapsulating drugs in hydrogels allows for continuous and intelligent drug release by controlling conditions such as the hydrogel's degradation rate, ambient temperature, and the pH of the medium; using hydrogels as wound dressings provides a protective layer to prevent bacterial infection and promote tissue regeneration; in the field of wearable sensors, hydrogels can monitor physiological signals such as blood pressure, heart rate, and respiratory rate in real time, providing important information for early disease diagnosis and treatment; in personal care products, hydrogels are a primary material in contact lenses, moisturizing masks, and other products, adhering to tissue surfaces and providing long-lasting moisturizing effects.

[0003] Polyvinyl alcohol (PVA) hydrogel is a non-toxic, chemically stable, biocompatible, and multifunctional synthetic polymer material that is currently widely used in biomedical fields such as drug delivery, tissue engineering, and biosensors. However, PVA hydrogels, when used alone, suffer from poor mechanical properties and low bioactivity, which significantly limits their application in certain areas. By combining it with bioactive silica, the mechanical strength and biofunctionality of PVA hydrogels can be effectively improved, resulting in a composite hydrogel material with excellent overall performance. If this composite hydrogel is applied as a coating to the surface of substrate materials such as metals, ceramics, and polymers, the superior properties of the substrate material (such as strength, toughness, and wear resistance) can be effectively combined with the unique advantages of the hydrogel (such as hydrophilicity, lubricity, and biocompatibility), thus creating new opportunities for its application in engineering, medical devices, and intelligent flexible devices. Summary of the Invention

[0004] Technical Problem: The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing polyvinyl alcohol composite hydrogel coatings on the surface of various substrate materials, so as to solve the problems of insufficient function and limited application fields of polyvinyl alcohol hydrogel coatings in traditional methods.

[0005] Technical Solution: This invention discloses a method for preparing a polyvinyl alcohol (PVA) composite hydrogel coating. Using polyvinyl alcohol (PVA), an organosilicon source, and polydopamine as main raw materials, a PVA-silica (PVA-SiO2) composite hydrogel coating is prepared on a substrate surface through coating technology and crosslinking treatment. First, the organosilicon source is fully hydrolyzed to obtain a uniform SiO2 sol. The SiO2 sol is then mixed with a PVA solution to obtain a PVA-SiO2 composite sol. This composite sol is uniformly coated onto a polydopamine-modified substrate surface, followed by crosslinking treatment to finally obtain the PVA-SiO2 composite hydrogel coating. Specific steps include:

[0006] (1) The organosilicon source was hydrolyzed under the catalysis of hydrochloric acid to obtain a uniform and transparent SiO2 sol;

[0007] (2) Dissolve PVA in deionized water at 90℃ to prepare a clear, viscous PVA solution;

[0008] (3) Take the SiO2 sol obtained in step (1) and the PVA solution obtained in step (2) and mix them to obtain PVA-SiO2 composite sol;

[0009] (4) Immerse the thoroughly cleaned substrate material in a polydopamine solution, then remove it, clean it, and dry it to obtain a polydopamine-treated substrate material.

[0010] (5) The PVA-SiO2 composite sol obtained in step (3) is coated onto the surface of the polydopamine-treated substrate material by coating technology to obtain a PVA-SiO2 composite sol coating.

[0011] (6) Crosslink the PVA-SiO2 composite sol coating to obtain the PVA-SiO2 composite hydrogel coating.

[0012] In step (1), the organosilicon source is one or more of tetramethoxysilane, tetraethoxysilane, methyltriethoxysilane, and ethyltriethoxysilane; the hydrolysis time is 0.1 to 48 h; and the concentration of the resulting SiO2 sol is 1 to 50 wt%.

[0013] In step (2), the concentration of the PVA solution is 1–30 wt%.

[0014] In step (3), the mass ratio of PVA to SiO2 in the PVA-SiO2 composite sol is 1:1 to 50:1; the mixing time is 0.1 to 24 h.

[0015] In step (4), the substrate material is one or more of metal, ceramic or polymer materials; the concentration of polydopamine solution is 0.1 to 20 mg / mL; the immersion time is 1 to 48 h; and the temperature is 20 to 80 °C.

[0016] In step (5), the coating technique is brush coating, dip coating, spin coating or spray coating.

[0017] In step (6), the crosslinking treatment includes physical crosslinking or chemical crosslinking.

[0018] Beneficial Effects: By adopting the above-mentioned solution, this invention overcomes the problems of insufficient function and limited application fields of single PVA hydrogel coatings in traditional methods, and provides a method for preparing PVA composite hydrogel coatings. The prepared PVA composite hydrogel coating has a smooth surface, uniform microstructure, and good mechanical properties and wettability, and can be used in biomedicine, crop cultivation, wastewater treatment, cosmetics, and other fields. The required equipment is simple, the process is easy to operate, has good repeatability, is mild and environmentally friendly, and is suitable for mass production. Compared with existing technologies, it has the following unique advantages:

[0019] (1) This invention prepares a PVA-SiO2 composite hydrogel coating by combining PVA solution with inorganic SiO2 sol at the molecular scale. It is expected to improve the shortcomings of PVA hydrogel coating such as low mechanical strength and poor biological activity, thereby expanding its application fields.

[0020] (2) By treating the substrate material with polydopamine, a polydopamine transition layer can be formed on the substrate surface, thereby effectively improving the bonding strength between the substrate material and the PVA-SiO2 composite hydrogel coating, making the coating less likely to fall off.

[0021] (3) Compared with the dry coating prepared by traditional technology, the PVA-SiO2 composite hydrogel coating obtained by the present invention has unique advantages such as good water retention, hydrophilicity, flexibility and adhesion, and can therefore be applied to many fields such as biomedicine, crop planting, sewage treatment, and cosmetics. Attached Figure Description

[0022] Figure 1 Scanning electron microscope image of the hydrogel coating prepared in Example 1 of the present invention.

[0023] Figure 2 The compression performance test curve of the hydrogel coating prepared in Example 1 of the present invention.

[0024] Figure 3 A photograph of the surface of the hydrogel coating prepared in Example 1 of the present invention being wetted by water. Detailed Implementation

[0025] The preparation method of the polyvinyl alcohol composite hydrogel coating of the present invention includes: using polyvinyl alcohol (PVA), organosilicon source, and polydopamine as main raw materials, a polyvinyl alcohol-silica (PVA-SiO2) composite hydrogel coating is prepared on the substrate surface through coating technology and crosslinking treatment; firstly, the organosilicon source is fully hydrolyzed to obtain a uniform SiO2 sol; the SiO2 sol is mixed with a PVA solution to obtain a PVA-SiO2 composite sol; the composite sol is uniformly coated onto the polydopamine-modified substrate surface, and then crosslinking treatment is performed to finally obtain the PVA-SiO2 composite hydrogel coating; the specific steps include:

[0026] (1) The organosilicon source is hydrolyzed under the catalysis of hydrochloric acid to obtain a uniform and transparent SiO2 sol; the organosilicon source is one or more of tetramethoxysilane, tetraethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, etc.; the hydrolysis time is 0.1 to 48 h; the concentration of the obtained SiO2 sol is 1 to 50 wt%.

[0027] (2) Dissolve PVA in deionized water at 90°C to prepare a clear, viscous PVA solution; the concentration of the PVA solution is 1-30 wt%.

[0028] (3) Take the SiO2 sol obtained in step (1) and the PVA solution obtained in step (2) and mix them to obtain PVA-SiO2 composite sol; the mass ratio of PVA to SiO2 in the PVA-SiO2 composite sol obtained after mixing is 1:1 to 50:1; the mixing time is 0.1 to 24 h;

[0029] (4) Immerse the thoroughly cleaned substrate material in a polydopamine solution, then remove it, clean it, and dry it to obtain a polydopamine-treated substrate material; the substrate material is one or more of the following materials: metal, ceramic, or polymer; the concentration of the polydopamine solution is 0.1-10 mg / mL; the immersion time is 1-48 h; and the temperature is 20-80 °C.

[0030] (5) The PVA-SiO2 composite sol obtained in step (3) is coated onto the surface of the polydopamine-treated substrate material using a coating technique to obtain a PVA-SiO2 composite sol coating; the coating technique is brush coating, dip coating, spin coating or spray coating;

[0031] (6) The PVA-SiO2 composite sol coating is subjected to crosslinking treatment to obtain a PVA-SiO2 composite hydrogel coating. The crosslinking treatment can be physical crosslinking or chemical crosslinking; the resulting composite hydrogel coating has a smooth surface, uniform microstructure, and good mechanical properties and wettability, and can be used in biomedicine, crop cultivation, sewage treatment, cosmetics and other fields.

[0032] The present invention will be further described below with reference to embodiments:

[0033] Example 1: A 30% (w / v) SiO2 sol was prepared by hydrolyzing tetramethoxysilane under hydrochloric acid catalysis for 0.5 h; PVA particles were dissolved in deionized water at 90 °C to prepare a 7% PVA solution; the SiO2 sol and PVA solution were mixed at a PVA to SiO2 mass ratio of 1:4, and stirred for 1 h to obtain a clear and transparent PVA-SiO2 composite sol; a thoroughly cleaned titanium sheet was immersed in a 2 mg / mL polydopamine solution at 60 °C for 24 h to obtain a polydopamine-treated titanium sheet; the PVA-SiO2 composite sol was brushed onto the surface of the polydopamine-treated titanium sheet to obtain a PVA-SiO2 composite sol coating; the PVA-SiO2 composite sol coating was physically crosslinked through freeze-thaw treatment to obtain a PVA-SiO2 composite hydrogel coating.

[0034] Experimental results: such as Figure 1 As shown, the surface of the PVA-SiO2 composite hydrogel coating obtained in Example 1 is generally smooth and the microstructure is uniform, indicating that SiO2 is uniformly distributed in the PVA matrix without aggregation or precipitation. Figure 2 As can be seen, the PVA-SiO2 composite hydrogel still maintains good elasticity and is not damaged when the compressive strain reaches 65%, and the compressive strength at this time is 0.34 MPa, which shows good compressive resistance. Figure 3 As shown, the PVA-SiO2 composite hydrogel coating obtained in Example 1 has good hydrophilicity, with a contact angle of approximately 42.3°.

[0035] Example 2: Tetraethoxysilane was hydrolyzed for 48 hours under hydrochloric acid catalysis to obtain a 5% (w / v) SiO2 sol; PVA particles were dissolved in deionized water at 90°C to prepare a 20% PVA solution; the SiO2 sol and PVA solution were mixed at a PVA to SiO2 mass ratio of 1:20 and stirred for 24 hours to obtain a clear and transparent PVA-SiO2 composite sol; a thoroughly cleaned glass slide was immersed in a 10 mg / mL polydopamine solution at 25°C for 2 hours to obtain a polydopamine-treated glass slide; the PVA-SiO2 composite sol was coated onto the surface of the polydopamine-treated glass slide to obtain a PVA-SiO2 composite sol coating; the PVA-SiO2 composite sol coating was chemically cross-linked to obtain a PVA-SiO2 composite hydrogel coating.

[0036] Example 3: Methyltriethoxysilane was hydrolyzed for 12 hours under hydrochloric acid catalysis to obtain a 40% (w / v) SiO2 sol; PVA particles were dissolved in deionized water at 90°C to prepare a 30% PVA solution; the SiO2 sol and PVA solution were mixed at a PVA to SiO2 mass ratio of 1:50 and stirred for 10 hours to obtain a clear and transparent PVA-SiO2 composite sol; a thoroughly cleaned plastic sheet was immersed in a 5 mg / mL polydopamine solution at 37°C for 10 hours to obtain a polydopamine-treated titanium sheet; the PVA-SiO2 composite sol was spin-coated onto the surface of the polydopamine-treated plastic sheet to obtain a PVA-SiO2 composite sol coating; the PVA-SiO2 composite sol coating was physically crosslinked through freeze-thaw treatment to obtain a PVA-SiO2 composite hydrogel coating.

Claims

1. A method for preparing a polyvinyl alcohol composite hydrogel coating, characterized in that: Using polyvinyl alcohol, organosilicon source, and polydopamine as main raw materials, a polyvinyl alcohol-silica composite hydrogel coating was prepared on the substrate surface through coating technology and crosslinking treatment. First, the organosilicon source was fully hydrolyzed to obtain a uniform SiO2 sol. The SiO2 sol was mixed with a PVA solution to obtain a PVA-SiO2 composite sol. The composite sol was uniformly coated onto the polydopamine-modified substrate surface, and then crosslinking treatment was performed to finally obtain the PVA-SiO2 composite hydrogel coating. The specific steps include: (1) The organosilicon source is hydrolyzed under the catalysis of hydrochloric acid to obtain a uniform and transparent SiO2 sol; the organosilicon source is one or more of tetramethoxysilane, tetraethoxysilane, methyltriethoxysilane, and ethyltriethoxysilane; the hydrolysis time is 0.1~48h; the concentration of the obtained SiO2 sol is 1~50wt% (2) Dissolve PVA in deionized water at 90°C to prepare a clear, viscous PVA solution; the concentration of the PVA solution is 1~30 wt%. (3) Take the SiO2 sol obtained in step (1) and the PVA solution obtained in step (2) and mix them to obtain PVA-SiO2 composite sol; in the PVA-SiO2 composite sol, the mass ratio of PVA to SiO2 is 1:1 to 50:1; the mixing time is 0.1 to 24 h; (4) Immerse the thoroughly cleaned substrate material in a polydopamine solution, then remove it, clean it, and dry it to obtain a polydopamine-treated substrate material; the substrate material is one or more of metal, ceramic or polymer materials; the concentration of the polydopamine solution is 0.1~20 mg / mL; the immersion time is 1~48 h; the temperature is 20~80℃; (5) The PVA-SiO2 composite sol obtained in step (3) is coated onto the surface of the polydopamine-treated substrate material using a coating technique to obtain a PVA-SiO2 composite sol coating; the coating technique is brush coating, dip coating, spin coating or spray coating; (6) The PVA-SiO2 composite sol coating is subjected to crosslinking treatment to obtain a PVA-SiO2 composite hydrogel coating; the crosslinking treatment includes physical crosslinking or chemical crosslinking.

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