Preparation method of polyvinyl alcohol composite hydrogel coating

Abstract

The invention discloses a preparation method of a polyvinyl alcohol composite hydrogel coating, and belongs to the field of coating preparation. Polyvinyl alcohol, an organic silicon source and polydopamine are used as main raw materials, and the polyvinyl alcohol-silicon dioxide composite hydrogel coating is prepared on the surface of a substrate through a coating technology and cross-linking treatment. The preparation method comprises the following steps: fully hydrolyzing an organic silicon source to obtain uniform silicon dioxide sol; mixing the silicon dioxide sol with a polyvinyl alcohol solution to obtain polyvinyl alcohol-silicon dioxide composite sol; uniformly coating the composite sol on the surface of a substrate subjected to polydopamine modification treatment; and crosslinking the composite sol on the surface of the substrate to obtain the polyvinyl alcohol-silicon dioxide composite hydrogel coating. The obtained coating is smooth in surface, uniform in microstructure, simple in required equipment, convenient to operate, low in energy consumption and cost, environment-friendly and easy for industrial production. The coating can be used in the fields of biomedicine, crop planting, sewage treatment, cosmetics and the like.

Description

Technical Field

[0001] The invention relates to the field of coating preparation, and in particular to a method for preparing a polyvinyl alcohol composite hydrogel coating. Background Art

[0002] Hydrogel is a gel material with a three-dimensional network structure formed by the swelling of polymers. This type of material has unique advantages such as high swelling and water retention, good flexibility and adhesion, and is therefore widely used in many fields such as sewage treatment, crop planting, anti-marine bioadhesion, and cosmetics. In addition, hydrogel materials also have good hydrophilicity, lubricity and biocompatibility, which provides possibilities for their application in biomedicine, medical health, personal care and other fields. For example, encapsulating drugs in hydrogels can achieve continuous and intelligent release of drugs by controlling conditions such as the degradation rate of hydrogels, ambient temperature, and pH value of the medium; using hydrogels as wound dressings can provide a protective layer for wounds, prevent bacterial infection, and promote tissue regeneration; using hydrogels in the field of wearable sensors can monitor human physiological signals such as blood pressure, heart rate, and respiratory rate in real time, providing an important basis for early diagnosis and treatment of diseases; in personal care products, hydrogels are the main materials for contact lenses, moisturizing masks and other products, which can adhere to the surface of tissues and provide long-term moisturizing effects.

[0003] Polyvinyl alcohol (PVA) hydrogel is a non-toxic, chemically stable, biocompatible, and multifunctional synthetic polymer material. It has been widely used in biomedical fields such as drug delivery, tissue engineering, and biosensors. However, PVA hydrogel has disadvantages such as poor mechanical properties and low biological activity when used alone, which greatly limits its application in certain fields. By compounding with bioactive silica, the mechanical strength and biological functionality of PVA hydrogel can be effectively improved, thereby obtaining a composite hydrogel material with excellent comprehensive performance. If this composite hydrogel is applied as a coating to the surface of a substrate material such as metal, ceramic, or polymer, the excellent 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), thereby creating new opportunities for its application in engineering, medical devices, and intelligent flexible devices. Summary of the invention

[0004] Technical problem: The purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for preparing a polyvinyl alcohol composite hydrogel coating on the surface of various substrate materials, so as to solve the problems of insufficient functions and limited application fields of the polyvinyl alcohol hydrogel coating in the traditional method.

[0005] Technical solution: The present invention is a method for preparing a polyvinyl alcohol composite hydrogel coating, which uses polyvinyl alcohol (PVA), an organic silicon source, and polydopamine as main raw materials, and prepares polyvinyl alcohol-silicon dioxide (PVA-SiO 2 ) composite hydrogel coating; first, the organic silicon source is fully hydrolyzed to obtain a uniform SiO 2 Sol; SiO 2 The sol was mixed with PVA solution to obtain PVA-SiO 2 Composite sol; the composite sol is uniformly coated on the surface of the polydopamine-modified substrate, and then cross-linked to finally obtain PVA-SiO 2 Composite hydrogel coating; the specific steps include:

[0006] (1) The organic silicon source is hydrolyzed under the catalysis of hydrochloric acid to obtain a uniform and transparent SiO 2 Sol;

[0007] (2) dissolving PVA in deionized water at 90° C. to prepare a clear, viscous PVA solution;

[0008] (3) Take the SiO obtained in step (1) 2 The sol is mixed with the PVA solution obtained in step (2) to obtain PVA-SiO 2 Composite sol;

[0009] (4) immersing the thoroughly cleaned substrate material in a polydopamine solution, then taking it out, cleaning it, and drying it to obtain a polydopamine-treated substrate material;

[0010] (5) PVA-SiO obtained in step (3) 2 The composite sol was coated onto the surface of the polydopamine treated substrate by coating technology to obtain PVA-SiO 2 Composite sol coating;

[0011] (6) PVA-SiO 2 The composite sol coating was cross-linked to obtain PVA-SiO 2 Composite hydrogel coating.

[0012] In step (1), the organic silicon source is one or more of tetramethoxysilane, tetraethoxysilane, methyltriethoxysilane, and ethyltriethoxysilane; the hydrolysis time is 0.1 to 48 hours; the obtained SiO 2 The concentration of the sol is 1 to 50 wt%.

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

[0014] In step (3), the PVA-SiO 2 In the composite sol, PVA and SiO 2 The mass ratio is 1:1 to 50:1; the mixing time is 0.1 to 24h.

[0015] In step (4), the substrate material is one or more of metal, ceramic or polymer materials; the concentration of the polydopamine solution is 0.1 to 20 mg / mL; the immersion time is 1 to 48 hours; 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 cross-linking treatment includes physical cross-linking or chemical cross-linking.

[0018] Beneficial effects: Due to the adoption of the above scheme, the present invention overcomes the problems of insufficient functions and limited application fields of single PVA hydrogel coating in traditional methods, and provides a method for preparing a PVA composite hydrogel coating. 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 planting, sewage treatment, cosmetics and other fields; the equipment required is simple, the process is easy to operate, the repeatability is good, it is mild and environmentally friendly, and it is suitable for mass production. Compared with the prior art, it has the following unique advantages:

[0019] (1) The present invention combines PVA solution with inorganic SiO 2 Sol-gel composites were used to prepare PVA-SiO 2 Composite hydrogel coatings are expected to improve the shortcomings of PVA hydrogel coatings such as low mechanical strength and poor biological activity, thereby expanding their application areas.

[0020] (2) By treating the substrate material with polydopamine, a polydopamine transition layer can be formed on the substrate surface, thereby effectively improving the adhesion between the substrate material and PVA-SiO 2 The bonding strength between the composite hydrogel coatings makes the coatings not easy to fall off.

[0021] (3) Compared with the dry coating prepared by conventional technology, the PVA-SiO 2 Composite hydrogel coatings have unique advantages such as good water retention, hydrophilicity, flexibility, and adhesion, and can therefore be used in many fields such as biomedicine, crop cultivation, sewage treatment, and cosmetics. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a scanning electron microscope photograph of the hydrogel coating prepared in Example 1 of the present invention.

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

[0024] Figure 3 This is a photograph showing that the surface of the hydrogel coating prepared in Example 1 of the present invention is wetted by water. DETAILED DESCRIPTION

[0025] The preparation method of the polyvinyl alcohol composite hydrogel coating of the present invention comprises: using polyvinyl alcohol (PVA), an organic silicon source, and polydopamine as main raw materials, and preparing polyvinyl alcohol-silicon dioxide (PVA-SiO 2 ) composite hydrogel coating; first, the organic silicon source is fully hydrolyzed to obtain a uniform SiO 2 Sol; SiO 2 The sol was mixed with PVA solution to obtain PVA-SiO 2 Composite sol; the composite sol is uniformly coated on the surface of the polydopamine-modified substrate, and then cross-linked to finally obtain PVA-SiO 2 Composite hydrogel coating; the specific steps include:

[0026] (1) The organic silicon source is hydrolyzed under the catalysis of hydrochloric acid to obtain a uniform and transparent SiO 2 Sol; the organic silicon source is one or more of tetramethoxysilane, tetraethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, etc.; the hydrolysis time is 0.1 to 48 hours; the obtained SiO 2 The concentration of the sol is 1 to 50 wt %;

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

[0028] (3) Take the SiO obtained in step (1) 2 The sol is mixed with the PVA solution obtained in step (2) to obtain PVA-SiO 2 Composite sol; PVA-SiO obtained after mixing 2 PVA and SiO in composite sol 2 The mass ratio is 1:1 to 50:1; the mixing time is 0.1 to 24 hours;

[0029] (4) immersing the fully cleaned substrate material in a polydopamine solution, then taking it out for cleaning and drying 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 to 10 mg / mL; the immersion time is 1 to 48 hours; the temperature is 20 to 80° C.;

[0030] (5) PVA-SiO obtained in step (3) 2 The composite sol was coated onto the surface of the polydopamine treated substrate by coating technology to obtain PVA-SiO 2 Composite sol coating; the coating technique is brush coating, dip coating, spin coating or spray coating;

[0031] (6) PVA-SiO 2 The composite sol coating was cross-linked to obtain PVA-SiO 2 Composite hydrogel coating. The cross-linking treatment can be physical cross-linking or chemical cross-linking; the obtained composite hydrogel coating has a smooth surface, uniform microstructure, and good mechanical properties and wettability, and can be used in biomedicine, crop planting, sewage treatment, cosmetics and other fields.

[0032] The present invention will be further described below in conjunction with embodiments:

[0033] Example 1: Tetramethoxysilane was hydrolyzed under the catalysis of hydrochloric acid for 0.5 h to obtain SiO 2 Sol; PVA particles were dissolved in deionized water at 90°C to prepare a 7% PVA solution; SiO 2 Sol and PVA solution are based on the relationship between PVA and SiO 2 The mixture was mixed at a mass ratio of 1:4 and stirred for 1 h to obtain a clear and transparent PVA-SiO 2 Composite sol; immerse the fully cleaned titanium sheet in a 2 mg / mL polydopamine solution at 60°C and take it out after 24 hours to obtain a titanium sheet treated with polydopamine; 2 The composite sol was brushed onto the surface of the titanium sheet treated with polydopamine to obtain PVA-SiO 2 Composite sol coating; PVA-SiO 2 The composite sol coating was physically cross-linked by freeze-thaw treatment to obtain PVA-SiO 2 Composite hydrogel coating.

[0034] Experimental results: Figure 1 As shown, the PVA-SiO obtained in Example 1 2 The surface of the composite hydrogel coating is relatively smooth and has a uniform microstructure, indicating that SiO 2Evenly distributed in the PVA matrix without agglomeration or precipitation. Figure 2 It can be seen that PVA-SiO 2 When the compressive strain reaches 65%, the composite hydrogel still maintains good elasticity and is not destroyed. At this time, the compressive strength is 0.34MPa, showing good anti-compression performance. Figure 3 As shown, the PVA-SiO obtained in Example 1 2 The composite hydrogel coating has good hydrophilicity and its contact angle is about 42.3°.

[0035] Example 2: Tetraethoxysilane was hydrolyzed under the catalysis of hydrochloric acid for 48 hours to obtain SiO 2 Sol; PVA particles were dissolved in 90°C deionized water to prepare a 20% PVA solution; SiO 2 Sol and PVA solution are based on the relationship between PVA and SiO 2 The mixture was mixed at a mass ratio of 1:20 and stirred for 24 h to obtain a clear and transparent PVA-SiO 2 Composite sol; immerse the fully cleaned glass slide in a 10 mg / mL polydopamine solution at 25°C and take it out after 2 hours to obtain a polydopamine-treated glass slide; 2 The composite sol was dip-coated onto the surface of a polydopamine-treated glass slide to obtain PVA-SiO 2 Composite sol coating; PVA-SiO 2 The composite sol coating was chemically cross-linked to obtain PVA-SiO 2 Composite hydrogel coating.

[0036] Example 3: Methyltriethoxysilane was hydrolyzed under the catalysis of hydrochloric acid for 12 hours to obtain SiO 2 Sol; PVA particles were dissolved in deionized water at 90°C to prepare a 30% PVA solution; SiO 2 Sol and PVA solution are based on the relationship between PVA and SiO 2 The mixture was mixed at a mass ratio of 1:50 and stirred for 10 h to obtain a clear and transparent PVA-SiO 2 Composite sol; immerse the fully cleaned plastic sheet in a 5 mg / mL polydopamine solution at 37°C and take it out after 10 hours to obtain a polydopamine-treated titanium sheet; 2 The composite sol was spin-coated onto the surface of a polydopamine-treated plastic sheet to obtain PVA-SiO 2 Composite sol coating; PVA-SiO 2 The composite sol coating was physically cross-linked by freeze-thaw treatment to obtain PVA-SiO 2Composite hydrogel coating.

Claims

1. A method for preparing a polyvinyl alcohol composite hydrogel coating, characterized in that: Using polyvinyl alcohol (PVA), an organic silicon source, and polydopamine as main raw materials, a polyvinyl alcohol-silicon dioxide (PVA-SiO2) composite hydrogel coating is prepared on the surface of a substrate through coating technology and cross-linking treatment; first, the organic silicon 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 on the surface of a polydopamine-modified substrate, and then a cross-linking treatment is performed to finally obtain a PVA-SiO2 composite hydrogel coating; The specific steps include: (1) hydrolyzing the organic silicon source under the catalysis of hydrochloric acid to obtain a uniform and transparent SiO2 sol; (2) dissolving PVA in deionized water at 90° C. to prepare a clear, viscous PVA solution; (3) mixing the SiO2 sol obtained in step (1) and the PVA solution obtained in step (2) to obtain a PVA-SiO2 composite sol; (4) immersing the thoroughly cleaned substrate material in a polydopamine solution, then taking it out, cleaning it, and drying it to obtain a polydopamine-treated substrate material; (5) coating the PVA-SiO2 composite sol obtained in step (3) onto the surface of the polydopamine-treated substrate material by a coating technique to obtain a PVA-SiO2 composite sol coating; (6) The PVA-SiO2 composite sol coating is cross-linked to obtain a PVA-SiO2 composite hydrogel coating.

2. The method for preparing a polyvinyl alcohol composite hydrogel coating according to claim 1, characterized in that: In step (1), the organic silicon source is one or more of tetramethoxysilane, tetraethoxysilane, methyltriethoxysilane, and ethyltriethoxysilane; the hydrolysis time is 0.1 to 48 hours; and the concentration of the obtained SiO2 sol is 1 to 50 wt%.

3. The method for preparing a polyvinyl alcohol composite hydrogel coating according to claim 1, characterized in that: In step (2), the concentration of the PVA solution is 1 to 30 wt %.

4. The method for preparing a polyvinyl alcohol composite hydrogel coating according to claim 1, characterized in that: In step (3), in the PVA-SiO2 composite sol, the mass ratio of PVA to SiO2 is 1:1 to 50:1; and the mixing time is 0.1 to 24 hours.

5. The method for preparing a polyvinyl alcohol composite hydrogel coating according to claim 1, characterized in that: In step (4), the substrate material is one or more of metal, ceramic or polymer materials; the concentration of the polydopamine solution is 0.1 to 20 mg / mL; the immersion time is 1 to 48 hours; and the temperature is 20 to 80°C.

6. The method for preparing a polyvinyl alcohol composite hydrogel coating according to claim 1, characterized in that: In step (5), the coating technique is brush coating, dip coating, spin coating or spray coating.

7. The method for preparing a polyvinyl alcohol composite hydrogel coating according to claim 1, characterized in that: In step (6), the cross-linking treatment includes physical cross-linking or chemical cross-linking.

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