Super-hydrophilic surface modifier and preparation method thereof

Abstract

The invention belongs to the field of modified materials, and particularly relates to a super-hydrophilic surface modifier and a preparation method thereof. The super-hydrophilic surface modifier P (NVP-co-MAA) / Ag with anti-fogging, anti-fouling and antibacterial properties is developed on the basis of the anti-fogging, anti-fouling and antibacterial super-hydrophilic surface modifier P (NVP-co-MAA), the preparation process is simple and rapid, the condition is mild, the durability of the modified surface is good, the antibacterial property is excellent, a certain self-cleaning property is achieved, and the product has an excellent actual use effect.

Description

Technical Field

[0001] The invention belongs to the field of modified materials, and specifically relates to a super-hydrophilic surface modifier and a preparation method thereof. Background Art

[0002] Fog is a condensation of water vapor formed by small water droplets or ice crystals. It can have adverse effects on the use of transparent substrates, such as affecting the performance of astronomical observation instruments, precision optical testing equipment, camera lenses, etc. The fogging of car windshields may even cause traffic accidents. The fogging of medical equipment such as medical endoscopes can increase the difficulty and risk of surgery. The current common solution is to add an anti-fog coating to the surface of the transparent substrate, which mainly includes super-hydrophobic coatings and super-hydrophilic coatings. Although super-hydrophobic coatings can make water droplets roll off, their development requires strict control of the surface microstructure. Fluorine-containing silicon materials are expensive and pollute the environment, and the coating is easily contaminated by pollutants. Super-hydrophilic coatings, due to their high wettability, form a uniform water film with water vapor, reducing fogging. At the same time, they have self-cleaning properties and have great potential for development and application.

[0003] Based on this, those skilled in the art have tried a variety of methods to prepare super hydrophilic coatings. Prior art literature (Zhu Y, Guo G, Lu J, et al. A transparent hydrophilic coating for long-lasting anti-fogging with self-cleaning and antibacterial properties [J]. Chemical Engineering Journal, 2024, 496: 153773.) discloses a technical solution for surface modification of a glass slide using a solution comprising polyvinyl alcohol, alkyl polyglycoside and tetraethoxysilane. After soaking, drying and other steps, the obtained glass slide has a low water contact angle, good anti-fogging performance, and anti-fouling and certain anti-bacterial adhesion capabilities. Prior art literature (Wang X, LiS, Huang J, et al. A multifunctional and environmentally-friendly method to fabricate superhydrophilic and self-healing coatings for sustainable antifogging [J]. Chemical Engineering Journal, 2021, 409: 128228.) mainly treats the glass substrate with oxygen plasma, spin-coats a mixture of polyacrylic acid and dries it, and the obtained anti-fogging film has a low water contact angle, and the mechanical wear test shows that it has excellent durability. Prior art literature (Guo H, Xu T, Zhang J, et al. A multifunctional anti-fog, antibacterial, and self-cleaning surface coating based on poly (NVP-co-MA) [J]. Chemical Engineering Journal, 2018, 351: 409-417.) discloses a technical solution for preparing poly (N-vinyl pyrrolidone-co-maleic anhydride). After a series of treatments, the obtained glass slide has a low water contact angle, anti-fogging, self-cleaning and certain anti-bacterial adhesion capabilities. However, the preparation process of these super-hydrophilic coatings is cumbersome, with high requirements for conditions, long time consumption, and most of them require pretreatment of the substrate. In some special occasions, such as medical endoscopes and other medical detection equipment, in addition to anti-fogging, they also need to have antibacterial functions. Although super-hydrophilic coatings have a certain anti-adhesion effect on bacteria, their antibacterial ability needs to be improved. Common antibacterial substances include metal nanoparticles and their corresponding metal oxides, especially silver, which is widely used as a bacterial inhibitor. Silver nanocomposites are considered non-toxic and environmentally friendly in biomedical applications.Polyvinylpyrrolidone is often used as a stabilizer in the synthesis of metal nanoparticles to prevent particle aggregation.

[0004] Therefore, there is an urgent need for a super-hydrophilic surface modifier with anti-fog, anti-fouling and antibacterial properties to meet the application needs of more practical production and life scenarios. Summary of the Invention

[0005] In order to solve the above technical problems, the first aspect of the present invention provides an anti-fog and anti-fouling super-hydrophilic surface modifier P(NVP-co-MAA) solution; in the present invention, P(NVP-co-MAA) is a poly(N-vinylpyrrolidone-co-methacrylic acid) copolymer.

[0006] As an implementable case, the raw materials for preparing the P(NVP-co-MAA) solution include NVP (vinyl pyrrolidone), MAA (methacrylic acid), an initiator, a base, an organic solvent and deionized water.

[0007] As an practicable example, the molar ratio of NVP to MAA is (3-7): (7-3).

[0008] P(NVP-co-MAA) forms a super-hydrophilic surface on glass slides, achieving excellent anti-fog effects. This is primarily due to the high hydrophilicity of MAA and the hydrophilicity and hygroscopicity of the PVP segment (polyvinylpyrrolidone). When water droplets contact the modified surface, the negatively charged carboxylate ions in MAA react with counterions in the water to form a hydration layer. The hygroscopicity of PVP allows water molecules in contact with the coating surface to quickly enter the coating, preventing large amounts of water molecules from condensing into droplets on the glass surface, thus achieving the anti-fog effect.

[0009] As an implementable example, the initiator includes AIBN (azobisisobutyronitrile) or BPO (benzoyl peroxide).

[0010] Furthermore, the amount of the initiator used is 2-5% of the total molar amount of NVP and MAA.

[0011] Furthermore, the amount of the initiator used is 3% of the total molar amount of NVP and MAA.

[0012] As an implementable case, the mass concentration of P(NVP-co-MAA) in the P(NVP-co-MAA) solution is 0.05-0.2 wt.%.

[0013] When the mass concentration of P(NVP-co-MAA) in the P(NVP-co-MAA) solution is 0.05-0.2wt.%, the contact angle of the water droplet on the surface of the modified glass slide material is less than 10°, reflecting excellent hydrophilic properties. However, when the mass concentration of P(NVP-co-MAA) is greater than 0.2wt.%, as the concentration increases, the contact angle will increase and the hydrophilic properties will decrease accordingly.

[0014] As an implementable example, the base includes potassium hydroxide or sodium hydroxide.

[0015] Furthermore, the alkali is sodium hydroxide.

[0016] As an implementable example, the solvent includes isopropyl alcohol.

[0017] The second aspect of the present invention provides a method for preparing an anti-fog and anti-fouling super-hydrophilic surface modifier P (NVP-co-MAA) solution, comprising:

[0018] S1. Dissolve NVP and MAA in a solvent, add an initiator, and react at 60-70°C for 2-3 hours under a nitrogen atmosphere. After the reaction, wash with anhydrous ethanol and then with petroleum ether. Dry the washed product at 40-50°C to constant weight to obtain P(NVP-co-MAA);

[0019] S2. Add alkali to P(NVP-co-MAA) and dilute with deionized water until the pH of the system is 7-10 to obtain a P(NVP-co-MAA) solution.

[0020] In the present invention, as the pH value increases, the anti-fog effect of the P(NVP-co-MAA) solution improves. This is mainly because the carboxyl groups contained in the P(NVP-co-MAA) polymer are sensitive to the pH of the system. Different pH environments affect the various properties of the copolymer. When the pH is 7-10, especially when the pH is 9, the adsorption morphology of P(NVP-co-MAA) is different from that in the acidic environment. The copolymer is no longer in a state of agglomeration and accumulation, but is stretched and adsorbed on the surface of the glass slide. Because most of the carboxyl groups at this time are deprotonated to form carboxylate ions, the electrostatic repulsion between the copolymer chains becomes larger.

[0021] The third aspect of the present invention provides an anti-fog, anti-fouling and antibacterial super-hydrophilic surface modifier P(NVP-co-MAA) / Ag. The raw materials for preparing P(NVP-co-MAA) / Ag include an anti-fog and anti-fouling super-hydrophilic surface modifier P(NVP-co-MAA) solution and a silver ammonia solution.

[0022] As an implementable case, the mass ratio of the P(NVP-co-MAA) solution to the silver ammonia solution is (25-200):1.

[0023] The fourth aspect of the present invention provides a method for preparing an anti-fog, anti-fouling and antibacterial super-hydrophilic surface modifier P(NVP-co-MAA) / Ag, comprising:

[0024] The P(NVP-co-MAA) solution and the silver ammonia solution are mixed and stirred to react to obtain a superhydrophilic surface modifier, namely P(NVP-co-MAA) / Ag. P(NVP-co-MAA) / Ag needs to be refrigerated and stored at 0-5°C and can be used immediately.

[0025] As a feasible case, the reaction time is 0.5-3h.

[0026] As an practicable example, the reaction temperature is 60-70°C.

[0027] The P(NVP-co-MAA) / Ag or P(NVP-co-MAA) solution prepared in the present invention is relatively easy to use. The surface material to be modified only needs to be placed in the P(NVP-co-MAA) / Ag or P(NVP-co-MAA) solution and stirred for 1 minute to form a coating on the surface.

[0028] Beneficial effects

[0029] (1) The method for using the superhydrophilic surface modifier provided in this application is simple and quick to operate. The modification can be completed by simply immersing the substrate in a P(NVP-co-MAA) solution or P(NVP-co-MAA) / Ag for 1 minute. No complicated pretreatment or curing steps are required, which significantly improves production efficiency and is suitable for industrial applications.

[0030] (2) The surface modified with the super-hydrophilic surface modifier provided by this application has super-hydrophilic properties, with a water contact angle of <5°, which can effectively prevent the formation of fog droplets and maintain the clarity of transparent substrates. At the same time, its hydrophilicity can also prevent the adhesion of oil stains, achieving a self-cleaning function, suitable for various scenarios such as lenses and windshields.

[0031] (3) This application introduces nanosilver through the use of silver ammonia solution, and the antibacterial rate of the modified surface against Staphylococcus aureus and Escherichia coli is as high as over 99.6%, which solves the problem of bacterial growth in medical equipment and other occasions, and has broad-spectrum antibacterial ability.

[0032] (4) After using the super-hydrophilic surface modifier provided by the present invention, the modified surface can still maintain good anti-fog performance and super-hydrophilicity after 150 thermal anti-fog cycles, 100 tape peelings and 90 days of storage, showing excellent mechanical stability and environmental adaptability, and is suitable for long-term use.

[0033] (5) The surface modifier provided in this application avoids the use of fluorine-containing silicon materials, reducing environmental pollution. Furthermore, the coating possesses triple functions of anti-fog, anti-fouling, and antibacterial properties, meeting a variety of application needs, especially in the medical, optical, and automotive fields, with broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of the effect of the molar ratio of NVP and MAA on the surface properties of P(NVP-co-MAA) solution modification; Figure 1 A is a thermal anti-fog photo (test conditions: placed 3 cm above 165°C hot water for 30 seconds); Figure 1 B is a cold anti-fog photo (stored at -20℃ for 45 minutes and then returned to room temperature at 25℃ and 60% relative humidity); Figure 1 C is the transmittance; Figure 1 D is the water contact angle.

[0035] Figure 2 Schematic diagram of the effect of pH on the surface properties of P(NVP-co-MAA) solution modification; Figure 2 A is a thermal anti-fog photo (placed 3 cm above 65°C hot water for 30 seconds); Figure 2 B is a cold anti-fog photo (stored at -20℃ for 45 minutes and then returned to room temperature at 25℃ and 60% relative humidity); Figure 2 C is the transmittance; Figure 2 D is the water contact angle.

[0036] Figure 3 are AFM images of different glass slides; among them, Figure 3 A is a blank slide; Figure 3 B is the modified slide at pH = 5.0; Figure 3 C is the modified slide at pH = 9.0.

[0037] Figure 4 Schematic diagram of the effect of P(NVP-co-MAA) solution concentration on the modified surface properties; Figure 4 A and Figure 4 C is a thermal anti-fog photo; Figure 4 B and Figure 4 D is a schematic diagram of the water contact angle.

[0038] Figure 5 Schematic diagram of the durability of the surface modified by P(NVP-co-MAA) solution; Figure 5 A is a schematic diagram of the thermal anti-fog cycle test; Figure 5 B is a schematic diagram of the tape peeling test; Figure 5 C is a schematic diagram of the placement cycle test.

[0039] Figure 6 Schematic diagram of the self-cleaning property of the surface modified with P(NVP-co-MAA) solution; peanut oil stains on the surfaces of blank and modified glass slides were stained with Nile red. In the comparison before and after water rinsing, modified glass slide 1 was immersed and modified glass slide 2 was sprayed.

[0040] Figure 7 This is the performance test diagram of P(NVP-co-MAA) / Ag diluted 14 times, where Figure 7 A, Figure 7 B, Figure 7 C is the UV-visible spectrum; Figure 7 D, Figure 7 E, Figure 7 F is a schematic diagram of the reaction solution; Figure 7 G is TEM; Figure 7 H is the particle size distribution; Figure 7 I is the XPS graph.

[0041] Figure 8 Schematic diagram of the antibacterial performance of P(NVP-co-MAA) / Ag.

[0042] Figure 9 Schematic diagram of the antibacterial performance of the plate colony counting method; Figure 9 A is the photos of S. aureus and E. coli culture dishes corresponding to the control group, P(NVP-co-MAA) modified slides, and P(NVP-co-MAA) / Ag modified slides; Figure 9 B is the corresponding colony number graph; Figure 9 C is the growth inhibition rate of P(NVP-co-MAA) / Ag modified glass slide on S. aureus and E. coli, and the control group is a blank glass slide.

[0043] Figure 10 The hydrophilic performance test diagram of P(NVP-co-MAA) / Ag modified glass slide; Figure 10 A is the water contact angle; Figure 10 B is a thermal anti-fog photo; Figure 10 C is a cold anti-fog photo; Figure 10 D is the transmittance; Figure 10 E is the transmittance in a room temperature environment of 25°C and 60% relative humidity after being stored at -20°C for 45 minutes; Figure 10 F is the water contact angle between the blank glass slide and the P(NVP-co-MAA) / Ag modified glass slide after 100 cycles of thermal anti-fogging, 100 tape peeling cycles, and 40 days of storage; Figure 10 G is a thermal anti-fog photo. DETAILED DESCRIPTION

[0044] 1. Test characterization instruments

[0045] Nuclear magnetic resonance spectrometer ( 1 The ratio of monomer NVP and MAA was calculated by spectral integration of H-NMR, DMX500, Bruker, Germany; the molecular weight of polymer P(NVP-co-MAA) was determined by gel permeation chromatography (GPC, HLC-8320, Tosoh Corporation, Japan); the contact angle of water droplets on the substrate surface was measured by sessile drop method at room temperature using an optical contact angle meter (OCA-40, Beijing Dongfang Defei Instrument Co., Ltd.), the drop volume was 2.5 μL, and at least three locations were selected for each sample; the transmittance of glass slides in the visible light region was measured by ultraviolet-visible near-infrared spectrophotometer (UV-3600plus, Shimadzu Corporation, Japan); the morphology and roughness of the coating surface were observed by atomic force microscopy (AFM, Dimension FastScan, Bruker, Germany), using tapping mode and a scanning range of 10 μm × 10 μm; the morphology and distribution of silver nanoparticles were observed by transmission electron microscopy (TEM, JEM-2100PLUS, JEOL Ltd.), and the nanostructured samples were analyzed by spectral spectroscopy (TEM). The particle size distribution of the synthesized silver nanoparticles was statistically analyzed using Measurer software; the elemental composition of the material surface was analyzed using an X-ray photoelectron spectrometer (XPS, Axis supra, Kratos, UK); and the absorbance of the solution in the ultraviolet-visible region was measured using a double-beam UV-visible spectrophotometer (TU-1950, Beijing Spectrum General Instrument Co., Ltd.).

[0046] 2. Thermal anti-fog test

[0047] The modified slide was placed 3 cm above 65°C hot water for 30 seconds and immediately photographed on a background with the word "Antifogging".

[0048] 3. Cold anti-fog test

[0049] The modified slides were placed in a -20°C environment for 45 minutes, then returned to a room temperature of 25°C and 60% relative humidity, and photographed immediately.

[0050] 4. Stability test

[0051] One cycle consists of holding the modified glass slide 3cm above 65°C hot water for 30 seconds before drying. A tape peeling cycle involves applying tape to the glass slide surface, pressing back and forth until the two adhere tightly, and then peeling the tape from the surface. A long-term storage test involves placing the glass slide in a laboratory environment and monitoring the effect of storage time on its anti-fog performance. The coating's stability is assessed by taking thermal anti-fog photographs and measuring water contact angles.

[0052] 5. Antifouling test

[0053] Edible peanut oil was dyed with Nile red dye and sprayed on the surface of blank glass slides and modified glass slides. After leaving it for one day, it was rinsed with deionized water to observe the ease with which the stain was washed away by water and the residue on the glass slide.

[0054] 6. Antibacterial test

[0055] Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) were used in the antibacterial experiment. The bacteria were cultured in nutrient broth (NB) at 37°C overnight, and the bacterial solution concentration was diluted with sterile phosphate buffered saline (PBS). Nutrient agar plates (NA) were used as solid culture medium.

[0056] The antibacterial activity of P(NVP-co-MAA) / Ag was evaluated by the inhibition zone test. The S. aureus and E. coli cultures after overnight culture were diluted with sterile PBS to a concentration of 10 8 CFU / mL, add it to sterilized NA at a volume ratio of 1:100 and mix well. Pour the plate and punch holes with an Oxford cup. Add 100 μL of sample into the holes. Diffusion at 4 °C for 2 h, then place it in a 37 °C incubator for 18 h. Observe whether an inhibition zone appears and its diameter.

[0057] The antibacterial properties of the modified glass slide surface were characterized by plate colony counting experiments. The concentration of S. aureus and E. coli bacterial solutions was adjusted to 10 6 CFU / mL, take 500 μL of bacterial solution in a 24-well plate, then put a 1 cm × 1 cm glass slide sample, 37 ° C, 200 rpm shaking culture for 60 min, dilute the cultured bacterial solution 10 2 times, apply 100 μL to the NA surface, and count the colonies on the plate surface after incubation at 37°C for 14 hours. Np and Ns represent the number of colonies on the blank glass slide and the modified glass slide respectively. The antibacterial effect of the modified glass slide is characterized by the bacterial growth inhibition rate. The calculation formula is:

[0058]

[0059] The anti-fog performance of the modified glass slide was characterized by means of hot anti-fog test, cold anti-fog test, water contact angle test, transmittance test, etc., and the effects of factors such as the monomer molar ratio of copolymer NVP and MAA, the pH value of the aqueous solution, the concentration of the aqueous solution, and the immersion time of the glass slide in the solution on the anti-fog performance of the surface were evaluated to screen out the optimal conditions.

[0060] Example 1

[0061] This example provides a super hydrophilic surface modifier P (NVP-co-MAA) solution with anti-fog and anti-fouling properties.

[0062] The raw materials for preparing the P(NVP-co-MAA) solution are NVP, MAA, AIBN, NaOH, isopropanol and deionized water; the molar ratio of NVP to MAA is 6:4, the total molar amount of NVP and MAA is 0.05 mol; the amount of AIBN used is 3% of the total molar amount of NVP and MAA.

[0063] Example 2

[0064] This example provides a method for preparing a super-hydrophilic surface modifier P (NVP-co-MAA) solution with anti-fog and anti-fouling properties, the specific steps are as follows:

[0065] S1. Dissolve NVP and MAA in 30 mL of isopropanol, add AIBN, and react at 65°C for 3 h under nitrogen. After the reaction, wash the precipitate with 300 mL of anhydrous ethanol, repeat four times; then wash the precipitate with petroleum ether, repeat twice; dry the washed product at 45°C to constant weight to obtain P(NVP-co-MAA);

[0066] S2. P(NVP-co-MAA) was added to a 1 M NaOH solution having an equal molar amount of MAA, and diluted with deionized water to a pH of 9 to obtain a P(NVP-co-MAA) solution.

[0067] 1. NVP and MAA molar ratio exploration test

[0068] The pH value of the P(NVP-co-MAA) solution was fixed at 9.0, and the mass concentration of P(NVP-co-MAA) was 0.2wt.%. The surface-treated glass slide to be modified was immersed in the solution at a shaking speed of 200rpm for 30min. The molar ratio of NVP and MAA monomers was changed to explore the effect of the monomer molar ratio on the anti-fog performance and determine the optimal monomer molar ratio.

[0069] Figure 1A is a photo of a blank glass slide and glass slides with different monomer molar ratios undergoing thermal antifogging. After being placed 3 cm above 65°C hot steam for 30 seconds, the blank glass slide fogged severely, and the background text was blurred. However, all modified glass slides maintained good clarity, and the word "Antifogging" on the background plate could be clearly seen. Figure 1 B is a cold anti-fogging photograph of a blank glass slide and glass slides with different monomer molar ratios. After being stored in a -20°C environment for 45 minutes and then returned to a room temperature environment of 25°C and 60% relative humidity, the blank glass slide quickly fogged up, making the background text indistinguishable. In contrast, the corresponding five groups of modified glass slides maintained good visibility, and the word "Antifogging" can be clearly seen in the photograph; Figure 1 C is the light transmittance of the blank glass slide and the glass slides with different monomer molar ratios in the visible light range. The modified glass slides show a transmittance comparable to that of the blank glass slides, both in the range of 88%-91%, indicating that surface modification does not affect the transmittance of the glass slides; Figure 1 D is the water contact angle of the blank glass slide and the glass slides with different monomer molar ratios. When a water droplet with a volume of 2.5 μL contacts the surface of the blank glass slide, it is observed that the morphology of the water droplet does not change much and the contact angle changes slowly. The final average contact angle is 24.1°. When it contacts the surface of the modified glass slide, the water droplet quickly spreads on the surface. The water contact angle of the surface with a monomer molar ratio of 3:7 is 8.4°, the surface with a monomer molar ratio of 4:6 is 6.6°, and the corresponding contact angle of the monomer molar ratio of 5:5 is 6.4°. Even when the monomer molar ratio is 6:4, the water droplet almost completely spreads into a water film on the surface of the glass slide, with a contact angle of only 3.2°. The contact angle of the modified surface with a monomer molar ratio of 7:3 is only 4.7°.

[0070] The modified surfaces with the aforementioned monomer molar ratios all exhibited water contact angles within 10°. This means that regardless of the ratio of NVP to MAA, P(NVP-co-MAA) consistently formed a super-hydrophilic surface on the glass slide, resulting in an excellent anti-fog effect. This is primarily due to the high hydrophilicity of MAA and the hydrophilicity and hygroscopicity of the PVP segment. When water droplets contact the modified surface, the negatively charged carboxylate ions in MAA react with counterions in the water to form a hydration layer. The hygroscopicity of PVP also allows water molecules in contact with the coating surface to quickly enter the coating, preventing large amounts of water molecules from condensing into droplets on the glass slide surface.

[0071] Therefore, in summary, when the molar ratio of NVP to MAA is 6:4, the anti-fog effect of P(NVP-co-MAA) is optimal.

[0072] 2. pH exploration test of P(NVP-co-MAA) solution

[0073] The molar ratio of the raw materials NVP and MAA monomers of the P(NVP-co-MAA) solution was fixed at 6:4, the mass concentration of P(NVP-co-MAA) in the P(NVP-co-MAA) solution was 0.2wt.%, and the glass slide was immersed in the solution at an oscillating speed of 200 rpm for 30 min. The pH value of the aqueous solution was changed to explore the effect of pH on the anti-fog performance and determine the optimal pH.

[0074] Figure 2 A is a photo of the thermal antifogging of a blank glass slide and glass slides with different pH values. After staying 3 cm above 65°C hot steam for 30 seconds, the blank glass slide was severely fogged, and the word "Antifogging" in the background was blurred. In comparison, the antifogging ability of the modified glass slides was improved. Among the modified glass slides with these five pH values, the antifogging effect gradually improved as the pH value increased from 5.0 to 6.0, 7.0, 8.0, and 9.0. The antifogging effect was greatly improved at pH = 7.0, and the background words in the photo were generally clear. The antifogging effect reached its peak at pH = 8.0 and 9.0. Figure 2 B is a cold anti-fog photo of a blank glass slide and glass slides with different pH values. After being placed at -20°C for 45 minutes and then brought to room temperature at 25°C and 60% relative humidity, the blank glass slide quickly fogged, affecting the legibility of the background text. The modified glass slide, on the other hand, had a relatively high anti-fog ability, similar to the hot anti-fog results, with pH = 5.0 being slightly inferior. Figure 2 C is the light transmittance of the blank glass slide and the glass slides with different pH values in the wavelength range of 400-800 nm. The results show that the adsorption of P(NVP-co-MAA) solution on the glass slide surface has almost no effect on its light transmittance; Figure 2 D is the water contact angle between the blank glass slide and the glass slides with different pH values. When a 2.5 μL water droplet is placed on the blank glass slide, the average contact angle is 24.1°. For the modified glass slides, the contact angles all drop significantly. Except for the contact angle of 12.1° at pH = 6.0, the water contact angles of the glass slides with other pH values are all less than 10°. The contact angles of pH = 5.0, 7.0, 8.0, and 9.0 are 8.6°, 7.2°, 6.4°, and 3.2°, respectively, forming a superhydrophilic surface, which is consistent with the hot and cold anti-fog results. When the pH of the P(NVP-co-MAA) solution is 9.0, the anti-fog effect is the best.

[0075] The formation of the above experimental phenomenon is mainly due to the fact that the carboxyl groups contained in P(NVP-co-MAA) are sensitive to pH. Different pH environments will affect the various properties of the copolymer. Through the titration curve of pH value and conductivity of P(NVP-co-MAA), the pKa is calculated to be 7.0. When pH = 5.0, the degree of ionization is only 8.3%. As the pH increases, the degree of ionization gradually increases until pH = 9.0, when the degree of ionization reaches 82.9%. At this time, the relative proportion of carboxylate ions in the copolymer solution is the largest and the hydrophilicity is also the highest. AFM was used to observe the adsorption of P(NVP-co-MAA) copolymer on the glass slide surface. The scanning range was 10μm×10μm. Figure 3 A is the two-dimensional plane image and three-dimensional stereogram of the blank glass slide surface. The surface is relatively flat, with a roughness Rq / Ra of 0.727nm / 0.525nm; Figure 3 When pH=5.0, the surface of the modified glass slide showed obvious adsorption of the copolymer, with a roughness of Rq / Ra of 9.28nm / 7.09nm. In this acidic environment, the copolymer contains a large number of carboxyl groups, the hydrophobic segments increase, the electrostatic repulsion between the molecular chains decreases, and it is easy to deposit and aggregate on the glass slide surface; when the pH increases to 9.0, as shown in FIG. Figure 3 As shown in Figure C, the surface roughness Rq / Ra of the copolymer after adsorption is 4.06nm / 2.95nm. The adsorption morphology is different from that in the acidic environment. The copolymer is no longer in a state of aggregation and accumulation, but is stretched and adsorbed on the surface of the glass slide. This is because most of the carboxyl groups at this time are deprotonated to form carboxylate ions, and the electrostatic repulsion between the copolymer chains becomes larger.

[0076] Therefore, in summary, when the pH of the P(NVP-co-MAA) solution is 9, the anti-fog effect of P(NVP-co-MAA) is optimal.

[0077] 3. Experimental study on the mass concentration of P(NVP-co-MAA) solution

[0078] The pH value of the P(NVP-co-MAA) solution was fixed at 9.0, and the molar ratio of NVP and MAA monomers was fixed at 6:4. The glass slide was immersed in the P(NVP-co-MAA) solution at a shaking speed of 200 rpm for 30 min. The concentration of the aqueous solution was changed to explore the effect of concentration on the anti-fog performance and determine the optimal concentration.

[0079] Figure 4A and 4B are the thermal anti-fog photos and water contact angles of blank glass slides and glass slides with different concentrations, respectively. When the mass concentration of P(NVP-co-MAA) is only 0.05wt.%, the thermal anti-fog photos are mostly clear, and the water contact angle is 10.4°. The anti-fog ability is greatly improved compared with the blank glass slide. With the increase of concentration, the background text can be clearly seen in the thermal anti-fog photos and the water contact angle is within 10°, indicating good hydrophilicity. When the concentration is 0.2wt%, the water contact angle reaches a minimum of 3.7°. At this time, the adsorption of P(NVP-co-MAA) copolymer on the glass slide surface has reached equilibrium. Subsequently, an increase in concentration will lead to an increase in the contact angle.

[0080] The methods for using the P(NVP-co-MAA) solution and P(NVP-co-MAA) / Ag in the present invention are both as follows: placing a glass slide to be modified in a surface modifier and stirring for modification.

[0081] 4. Stirring time exploration test

[0082] The molar ratio of NVP and MAA monomers in P(NVP-co-MAA) was fixed at 6:4, the solution pH was 9.0, and the mass concentration was 0.2wt.%. The immersion time of the glass slide in the P(NVP-co-MAA) solution was changed to explore the effect of immersion time on the anti-fog performance.

[0083] Figure 4 C and 4D show the thermal anti-fog performance of a blank glass slide and glass slides with different immersion times, respectively. After just one minute of immersion in the copolymer solution, the thermal anti-fog performance was excellent, with the water contact angle dropping sharply from an initial 24.1° to 3.8°, achieving ideal results. This demonstrates that the P(NVP-co-MAA) copolymer rapidly adsorbs to the glass slide at low concentrations, forming a super-hydrophilic surface and exhibiting excellent anti-fog properties.

[0084] 5. Modification durability test of P(NVP-co-MAA) solution

[0085] P(NVP-co-MAA) can be quickly adsorbed onto glass slides to form a super-hydrophilic surface with excellent anti-fog performance. From an application perspective, it is also hoped that it has good durability. Therefore, the modified glass slides were subjected to thermal anti-fog cycle tests, tape peeling tests, and long-term placement tests.

[0086] Place the glass slide on 65℃ hot steam for 30s, wait for the water mist to dry, then place it on hot steam again, repeat this cycle, and test the changes in the water contact angle of the modified glass slide after different cycles. The results are as follows: Figure 5A, the contact angle changes very little within 20 cycles, remaining within 5°. As the number of cycles increases, the contact angle gradually increases, but the growth trend is slow. After 150 cycles, the contact angle is still below 10°. After 200 cycles, the contact angle increases significantly and exceeds 10°. The lower right corner is a comparison of a blank glass slide that has been thermally defogged once and a modified glass slide that has been thermally defogged 200 times. After 200 cycles, the transmittance of some areas deteriorates. Figure 5 B shows the change in contact angle with the number of tape peelings. A highly sticky tape was adhered to the surface of the modified glass slide and pressed back and forth to ensure a tight fit between the two before the tape was peeled off from the surface. It was found that peeling the tape within 10 times had almost no effect on the water contact angle of the modified glass slide. When the number of peelings increased to 20, the contact angle showed a significant increase. After that, the contact angle changed slowly with the increase in the number of peelings. After 100 peelings, the surface contact angle remained at 7.7°, and the thermal anti-fog effect remained good. Figure 5 C shows the change in contact angle of the modified glass slide after being placed in a laboratory environment for different periods of time. The contact angle gradually increases with the increase in placement time, increasing from 3.1° to 8.4° after 90 days, while still maintaining a super hydrophilic surface and a high anti-fog level.

[0087] The above three tests show that the surface modified by P(NVP-co-MAA) solution has good stability and durability.

[0088] 6. Self-cleaning test of P(NVP-co-MAA) solution modification

[0089] P(NVP-co-MAA) is adsorbed on the glass slide to form a super-hydrophilic surface. Its hydrophilicity can make the droplets quickly spread into a layer of water film on the surface, thereby avoiding blurred vision caused by light scattering; at the same time, the high hydrophilicity can prevent oil droplets from adhering to the surface. Edible peanut oil is stained with Nile red for observation. It is sprayed on the surface of blank glass slides and modified glass slides. After one day, the oil stains are rinsed with water to observe the removal of stains. Since P(NVP-co-MAA) can be quickly adsorbed on the surface of the glass slide, and from a practical and convenient point of view, in addition to oscillating and soaking the glass slide in the copolymer solution for 1 minute, the modified glass slide is prepared by directly spraying the solution on the surface of the glass slide and then drying it. They are marked as modified glass slide 1 and modified glass slide 2 respectively. The comparison of the edible oil-contaminated glass slide before and after rinsing with water is shown in Figure 6 It can be seen intuitively that the oil stains on the modified glass slide are easy to wash away and no stains remain, while the stains on the blank glass slide adhere to the surface and are not easy to wash away, verifying the self-cleaning performance of the P(NVP-co-MAA) solution modification.

[0090] Example 3

[0091] This example provides a super-hydrophilic surface modifier P(NVP-co-MAA) / Ag with anti-fog, anti-fouling and antibacterial properties.

[0092] The raw materials for preparing the P(NVP-co-MAA) / Ag are P(NVP-co-MAA) solution and silver ammonia solution, and the mass ratio of P(NVP-co-MAA) solution to silver ammonia solution is 100:1; wherein the molar concentration of the silver ammonia (Ag(NH3)2NO3) solution is 11.8mmol / L.

[0093] Example 4

[0094] This example provides a method for preparing a super-hydrophilic surface modifier P(NVP-co-MAA) / Ag with anti-fog, anti-fouling and antibacterial properties, the specific steps of which are as follows:

[0095] The P(NVP-co-MAA) solution and the silver ammonia solution were mixed and stirred at 65°C for 3 hours to obtain a superhydrophilic surface modifier P(NVP-co-MAA) / Ag.

[0096] 7. Exploration, testing and characterization of the mass ratio of P(NVP-co-MAA) to Ag(NH3)2NO3

[0097] In the synthesis of silver nanoparticles, the effects of the mass concentration of the P(NVP-co-MAA) solution, the pH value of the solution, and the reaction time on the results were considered. The pH of the P(NVP-co-MAA) solution was fixed at 10.0 and the reaction time was 3h. The mass ratio of P(NVP-co-MAA) to Ag(NH3)2NO3 was changed to 25:1, 50:1, 100:1, and 200:1 (the amount of Ag(NH3)2NO3 was kept constant). The UV-visible spectrum of the reaction solution after dilution by 14 times was compared with the corresponding solution photograph. Figure 7 As shown in Figures A and 7D, as the mass ratio increases, the color of the reaction solution darkens significantly, gradually changing from light yellow to a thick yellow-brown color. The intensity of the ultraviolet absorption peak increases significantly, and the characteristic absorption peak position of nanosilver shifts. When the mass ratio is 25:1, a weak absorption peak appears at 467nm, indicating that silver nanoparticles have been synthesized but at a low concentration. As the mass ratio increases to 100:1, the absorption peak gradually blue-shifts to 436nm, while the peak width decreases. The blue shift of the absorption peak position may be due to the decrease in the aspect ratio of the nanosilver particles. The change in peak width indicates a change in the particle size distribution, and a narrower peak indicates a narrower particle size distribution. When the mass ratio increases to 200:1, the solution viscosity increases, the absorption peak intensity increases, but the peak position red-shifts and the peak becomes wider. Therefore, a mass ratio of P(NVP-co-MAA) to Ag(NH3)2NO3 of 100:1 is most conducive to the synthesis of nanosilver.

[0098] The mass ratio of P(NVP-co-MAA) to Ag(NH3)2NO3 was fixed at 100:1, the reaction time was 3h, and the pH value of the solution was changed. The UV-visible spectrum of the reaction solution after dilution 14 times was compared with the corresponding solution photo. Figure 7 As shown in Figures B and 7E, there is no absorption in an acidic environment of pH = 5.0, indicating that no nanosilver is generated; in a neutral environment of pH = 7.0, a characteristic absorption peak of nanosilver begins to appear at 454nm but the intensity is very weak; until under alkaline conditions, the absorption peak intensity increases rapidly, moves toward the short-wave direction, and the peak is narrow, indicating that the reaction is suitable for carrying out under alkaline conditions.

[0099] The m(P(NVP-co-MAA)):m(Ag(NH3)2NO3) ratio was determined to be 100:1 and the solution pH was 10.0. The effect of reaction time on the synthesis of silver nanoparticles was investigated. Figure 7 C and 7F are the UV-visible spectra of the reaction solution after being diluted 14 times at different times and the corresponding solutions. A large amount of nanosilver is produced at 30 minutes of reaction. As the reaction time increases, the color of the reaction solution deepens and the absorption peak intensity increases. At 3 hours, the absorption peak corresponds to a wavelength of 441nm, and the peak intensity is close to the maximum. The reaction is almost completed. After that, the peak shape does not change much and the intensity may even weaken as the reaction time increases. Therefore, a reaction time of 3 hours is selected.

[0100] The structures of silver nanoparticles synthesized under the optimal conditions of m(P(NVP-co-MAA)):m(Ag(NH3)2NO3) of 100:1, solution pH = 10.0 and reaction time of 3h were characterized. Figure 7 G is a TEM image, the silver nanoparticles are all spherical and well dispersed, with no obvious aggregation. The particle size distribution of nanosilver was statistically analyzed using Nano Measurer software, and the results are as follows: Figure 7 H, particle size distribution ranges from 1.6 nm to 2.8 nm, with an average particle size of 2.2 nm; Figure 7 I is the XPS spectrum of P(NVP-co-MAA) / Ag. The metallic Ag core shows two peaks at the Ag3d level: 3d5 / 2 at a binding energy of 367.8 eV and 3d3 / 2 at 373.8 eV, proving the successful preparation of nanosilver.

[0101] 8. P(NVP-co-MAA) / Ag antibacterial performance test

[0102] 100 μL of P(NVP-co-MAA) / Ag with different dilution gradients were added to the wells of S. aureus (Staphylococcus aureus) and E. coli (Escherichia coli) agar plates, respectively, and cultured at 37°C for 18 h. The antibacterial performance of P(NVP-co-MAA) / Ag was evaluated by observing the inhibition zone.

[0103] The experimental results are as follows Figure 8 The corresponding relationship between the dilution ratio and the concentrations of P(NVP-co-MAA) and Ag in P(NVP-co-MAA) / Ag, as well as the inhibition zone diameter data, are shown in Table 1. It can be observed that P(NVP-co-MAA) / Ag has obvious inhibition zones for both S. aureus and E. coli, and as the dilution ratio of the P(NVP-co-MAA) / Ag reaction solution increases (i.e., the silver concentration decreases), the inhibition zone diameter gradually decreases. When diluted to 128 times (Ag concentration of 5.2 μg / mL), it still has an inhibitory effect on S. aureus and E. coli, and no inhibition zone appears after further dilution. In the control group, water and different concentrations of P(NVP-co-MAA) were added, and no inhibition zone appeared.

[0104] The experimental results show that P(NVP-co-MAA) has no inhibitory effect on bacterial growth, while P(NVP-co-MAA) / Ag after the introduction of Ag has good antibacterial properties, which can be attributed to the broad-spectrum bactericidal properties of Ag, which is achieved through the dual synergistic effects of the contact bactericidal effect of nanosilver and the dissolution bactericidal effect of silver ions.

[0105] Table 1

[0106]

[0107]

[0108] Note: The initial diameter is 7.0 mm.

[0109] The antibacterial activity of different glass slide surfaces was evaluated by plate colony counting. The control group was a blank glass slide. The P(NVP-co-MAA)-modified glass slide used a solution with a mass concentration of 0.2% and a pH of 9.0. The P(NVP-co-MAA) / Ag-modified glass slide used a 40-fold diluted reaction solution (P(NVP-co-MAA) mass concentration of 0.2% and an Ag concentration of 16.7 μg / mL).

[0110] Figure 9A and B are the photos of S. aureus and E. coli culture dishes and the corresponding colony counts of blank glass slides, P(NVP-co-MAA) modified glass slides, and P(NVP-co-MAA) / Ag modified glass slides, respectively. The survival status of the colonies can be seen intuitively. The bacterial growth in the control group is relatively dense. The number of surviving colonies in the P(NVP-co-MAA) group is increased compared with the control group. This is because the super-hydrophilic surface has an anti-adhesion effect on bacteria. Bacteria are more likely to adhere to the surface of the blank glass slide, resulting in the control group having a higher survival rate. The number of bacteria in the bacterial liquid of the group was less than that in the P(NVP-co-MAA) group, indicating that the P(NVP-co-MAA) modified glass slide had a certain antibacterial effect; almost no colonies were observed on the surface of the culture dish corresponding to the P(NVP-co-MAA) / Ag modified glass slide, and the growth inhibition rates of S. aureus and E. coli could reach 99.6% and 99.7%, respectively, indicating that the P(NVP-co-MAA) / Ag modified surface had a good antibacterial effect, which was consistent with the results of the inhibition zone experiment.

[0111] 9. Hydrophilicity test of P(NVP-co-MAA) / Ag modified surface

[0112] The P(NVP-co-MAA) / Ag modified surface has an inhibitory effect on the growth of S. aureus and E. coli, indicating that P(NVP-co-MAA) / Ag can be successfully adsorbed onto the glass slide surface. In addition to the antibacterial Ag, there is also a large amount of P(NVP-co-MAA) in the reaction solution, so the hydrophilicity of the P(NVP-co-MAA) / Ag modified surface was investigated.

[0113] Figure 10 A, 10B, and 10C are photos of the water contact angle, hot anti-fog, and cold anti-fog of a blank glass slide and a P(NVP-co-MAA) / Ag-modified glass slide, respectively. It can be seen that the hydrophilicity of the modified glass slide has increased significantly, with a water contact angle of only 3.2°, forming a super-hydrophilic surface. After being placed 3 cm above 65°C hot water for 30 seconds or stored at -20°C for 45 minutes and then returned to room temperature (25°C, relative humidity 60%), the P(NVP-co-MAA) / Ag-modified glass slide showed no fogging, and the background text was still clearly visible, demonstrating the excellent anti-fog ability of the modified glass slide. Figure 10 D and 10E are the transmittances of the blank glass slide and the P(NVP-co-MAA) / Ag modified glass slide at room temperature and after being placed at -20°C for 45 minutes and then returned to room temperature. The transmittance of the P(NVP-co-MAA) / Ag modified glass slide is comparable to that of the blank glass slide, and it still maintains a high transmittance after 45 minutes at -20°C. Figure 10F and 10G show the water contact angle and thermal anti-fog photographs of a blank glass slide and a P(NVP-co-MAA) / Ag-modified glass slide that underwent durability testing. After 100 tape peeling cycles, 100 thermal anti-fog cycles, and 40 days of storage, the contact angle showed only a slight increase, and the thermal anti-fog photographs remained clear, indicating the good stability of the P(NVP-co-MAA) / Ag-modified surface. This indicates that the superhydrophilicity of the P(NVP-co-MAA) / Ag-modified surface is comparable to that of P(NVP-co-MAA) and is not affected by the addition of Ag.

Claims

1. An anti-fog and anti-fouling super-hydrophilic surface modifier, characterized in that: The super-hydrophilic surface modifier is a P(NVP-co-MAA) solution; The raw materials for preparing the P (NVP-co-MAA) solution include NVP, MAA, an initiator, a base, an organic solvent and deionized water.

2. The anti-fog and anti-fouling super-hydrophilic surface modifier according to claim 1, characterized in that The molar ratio of NVP to MAA is (3-7): (7-3).

3. The anti-fog and anti-fouling super-hydrophilic surface modifier according to claim 1, characterized in that The amount of the initiator used is 2-5% of the total molar amount of NVP and MAA.

4. The super-hydrophilic surface modifier with anti-fog and anti-fouling properties according to claim 1, characterized in that The initiator includes AIBN.

5. The anti-fog and anti-fouling super-hydrophilic surface modifier according to claim 1, characterized in that: The alkali includes potassium hydroxide or sodium hydroxide.

6. An anti-fog and anti-fouling super-hydrophilic surface modifier according to any one of claims 1 to 5, characterized in that: The preparation method of the P(NVP-co-MAA) solution comprises: S1. Dissolve NVP and MAA in a solvent, add an initiator, and react at 60-70°C under nitrogen for 2-3 hours. After the reaction, wash with anhydrous ethanol and then with petroleum ether. Dry the washed product at 40-50°C to constant weight to obtain P(NVP-co-MAA); S2. Add alkali to P(NVP-co-MAA) and dilute with deionized water until the pH of the system is 7-10 to obtain a P(NVP-co-MAA) solution.

7. A super-hydrophilic surface modifier for anti-fogging, anti-fouling and antibacterial properties, characterized in that: The preparation raw materials include silver ammonia solution and the P (NVP-co-MAA) solution according to any one of claims 1 to 5.

8. The anti-fog, anti-fouling and antibacterial super-hydrophilic surface modifier according to claim 7, characterized in that: The mass ratio of the P(NVP-co-MAA) solution to the silver ammonia solution is (25-200):

1.

9. A method for preparing the anti-fog, anti-fouling and antibacterial super-hydrophilic surface modifier according to any one of claims 7 to 8, characterized in that: include: The P(NVP-co-MAA) solution and the silver ammonia solution were mixed and stirred to react to obtain a super-hydrophilic surface modifier P(NVP-co-MAA) / Ag.

10. The method for preparing the anti-fog, anti-fouling and antibacterial super-hydrophilic surface modifier according to claim 9, characterized in that: The reaction time is 0.5-3h, and the reaction temperature is 60-70°C.

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