A method for preparing an anti-algal adhesion super-hydrophobic composite coating

Abstract

The application discloses a preparation method of an anti-algae-adhesion super-hydrophobic composite coating. The method comprises the following steps: uniformly dispersing epoxy resin into ester substances to obtain a mixed solution A; adding polyhexamethylene guanidine hydrochloride, polyvinylpyrrolidone, nano-TiO2, polytetrafluoroethylene micro powder, graphene oxide and gamma-aminopropyl triethoxysilane into the mixed solution A, uniformly mixing to obtain a mixed solution B; adding fluorine-containing silane and polyether amine curing agent into the mixed solution B, uniformly dispersing to obtain a mixed solution C; and spraying the mixed solution C to a substrate surface, and performing normal-temperature ventilation and drying to obtain the super-hydrophobic composite coating. The super-hydrophobic coating prepared by the method has the characteristics of low contact area with water, low viscous force and self-cleaning, and also has good anti-algae-adhesion performance, and has a wide application prospect in marine antifouling.

Description

Technical Field

[0001] This invention relates to a method for preparing a hydrophobic coating, and more particularly to a method for preparing a superhydrophobic composite coating that resists algae adhesion. Background Technology

[0002] Microorganisms such as algae can easily grow and multiply on material surfaces. For example, bioadhesion on ships can reduce their speed, increase fuel consumption, maintenance costs, and emissions of harmful gases. Inspired by natural hydrophobic surfaces such as lotus leaves, biomimetic superhydrophobic surfaces have shown promising application prospects in the fields of anti-bioadhesion, corrosion prevention, and antifouling due to their unique wettability.

[0003] However, traditional superhydrophobic coatings suffer from mechanical instability issues, such as fragile microstructures that are extremely difficult to recover from physical damage caused by friction, compression, etc., posing a challenge to their large-scale application. Therefore, designing and constructing superhydrophobic coatings with good anti-bioadhesion, mechanical stability, and chemical stability is particularly important, while simplifying the preparation process and reducing costs.

[0004] Chinese patent CN107573811A discloses a wear-resistant, corrosion-resistant, and waterproof coating for environmental protection equipment. This coating uses nano-titanium dioxide and graphene oxide to prepare a corrosion-resistant and waterproof coating. However, the titanium dioxide content in this coating is less than 4 wt%, which is insufficient to inhibit algae adhesion and growth. While increasing the titanium dioxide content can resist algae adhesion and growth, it also affects the hydrophobic properties of the coating. This is mainly because a higher titanium dioxide content interferes with the function of graphene oxide, thus reducing the hydrophobic properties of the coating. Therefore, it is impossible to obtain a coating with both superhydrophobic and anti-algae adhesion properties based on this patent. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide a method for preparing a superhydrophobic composite coating, solving the problem of how to prepare a coating that has both superhydrophobic properties and anti-algae adhesion properties.

[0006] Technical solution: The method for preparing a superhydrophobic composite coating according to the present invention includes the following steps:

[0007] (1) Epoxy resin is uniformly dispersed into ester substances to obtain mixed solution A;

[0008] (2) Add polyhexamethylene guanidine hydrochloride, polyvinylpyrrolidone, nano TiO2, polytetrafluoroethylene micro powder, graphene oxide and γ-aminopropyltriethoxysilane to mixed solution A, and mix well to obtain mixed solution B.

[0009] (3) Add fluorosilane and polyetheramine curing agent to mixed solution B, and disperse evenly to obtain mixed solution C;

[0010] (4) Spray the mixed solution C onto the substrate surface and dry it at room temperature to obtain the superhydrophobic composite coating.

[0011] This invention incorporates nano-TiO2 to inhibit algae adhesion and graphene oxide to increase the strength and density of the coating, thereby improving its hydrophobic properties. The invention also addresses the issue that nano-TiO2 at effective algae-inhibiting levels can interfere with the enhancement of hydrophobicity by graphene oxide, thus achieving a coating that balances hydrophobicity and anti-algae adhesion properties.

[0012] Preferably, in step (2), the mass ratio of polyhexamethylene guanidine hydrochloride: polyvinylpyrrolidone: nano-TiO2: graphene oxide is 1-3: 2-8: 20-50: 2-10.

[0013] Preferably, the ester includes at least one selected from butyl acetate, ethyl acetate, methyl acetate, phenyl acetate, and methyl benzoate; the fluorinated silane is 1H,1H,2H,2H-perfluorooctyltriethoxysilane. The preferred mass ratio of epoxy resin to ester is 2-4:25-45.

[0014] Preferably, the epoxy resin is E-51 and the polyetheramine curing agent is D-230.

[0015] Preferably, the particle size of the nano-TiO2 is 20-40 nm, and the particle size of the polytetrafluoroethylene micro powder is 1-2 μm.

[0016] Preferably, the mass ratio of the epoxy resin to the polyetheramine curing agent is 2-4:1-3.

[0017] Preferably, in steps (1) and (3), the dispersion method is to first perform ultrasonic vibration dispersion and then continue stirring dispersion.

[0018] Preferably, the ultrasonic oscillation dispersion method is to use an ultrasonic power of 160-200W and a frequency of 30-50kHz for oscillation dispersion for 10-30 minutes; the stirring dispersion method is to stir at 200-600r / min for 30-120 minutes.

[0019] Preferably, in step (4), the mixed solution C is sprayed onto the substrate surface and dried at room temperature and ventilation by spraying with a spray gun, adjusting the vertical distance between the nozzle of the spray gun and the substrate to 10-20cm, spraying slowly for 30-45s at 0.4-0.6MPa, and the spraying speed is 2-6cm / s.

[0020] Preferably, the nozzle diameter is 0.3-0.7 mm.

[0021] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0022] 1. The superhydrophobic coating prepared by this invention not only has the characteristics of low contact area with water, low viscosity and self-cleaning, but also has good anti-algae adhesion performance, and has a broad application prospect in marine antifouling.

[0023] 2. This invention successfully constructs a micro / nano-scale layered structure on the coating surface. The superhydrophobic structure of the micro / nano-scale layered structure remains more intact after mechanical wear than a single nano-scale superhydrophobic surface. The prepared superhydrophobic coating combines the advantages of organic resins and inorganic particles, thereby endowing the coating with excellent self-cleaning and wear-resistant properties. Attached Figure Description

[0024] Figure 1 The image shows the contact angle measurement results of the superhydrophobic coating prepared in Example 1;

[0025] Figure 2 The image shows the contact angle measurement results of the superhydrophobic coating prepared in Example 2;

[0026] Figure 3 The image shows the contact angle measurement results of the superhydrophobic coating prepared in Example 3;

[0027] Figure 4 The image shows the contact angle measurement results of the superhydrophobic coating prepared in Example 4;

[0028] Figure 5 The image shows the contact angle measurement results of the superhydrophobic coating prepared in Example 5;

[0029] Figure 6 The image shows the contact angle measurement results of the superhydrophobic coating prepared in Example 6;

[0030] Figure 7 The image shows the contact angle measurement results of the superhydrophobic coating prepared in Example 7;

[0031] Figure 8 The image shows the contact angle measurement results of the coating prepared in Comparative Example 1;

[0032] Figure 9 Scanning electron microscope images of the superhydrophobic coating prepared in Example 1 at different magnifications;

[0033] Figure 10 The graph shows the relationship between the number of friction cycles and the wettability of the superhydrophobic coating prepared in Example 1.

[0034] Figure 11The algae resistance test results are for the superhydrophobic coating prepared in Example 1. Detailed Implementation

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

[0036] Example 1: The preparation method of the superhydrophobic composite coating is as follows:

[0037] (1) 3.3g of epoxy resin (E-51) was uniformly dispersed into 25g of butyl acetate to obtain mixed solution A. The dispersion method was to first perform ultrasonic vibration dispersion with an ultrasonic power of 180W and a frequency of 40kHz for 20min, and then continuously stir at 400r / min for 60min.

[0038] (2) Add 1g of polyhexamethylene guanidine hydrochloride, 2g of polyvinylpyrrolidone, 30g of nano-TiO2 with a particle size of 30nm, 10g of polytetrafluoroethylene micro powder with a particle size of 1.6μm, 2g of graphene oxide and 0.2g of γ-aminopropyltriethoxysilane (KH550) to mixed solution A, and mix well to obtain mixed solution B;

[0039] (3) Add 0.4g of 1H,1H,2H,2H-perfluorooctyltriethoxysilane (POTS) and 1.1g of polyetheramine curing agent (D-230) to mixed solution B, and disperse evenly to obtain mixed solution C; the dispersion method is the same as step (1).

[0040] (4) Using a spray gun with a nozzle diameter of 0.5 mm, the mixed solution C is slowly sprayed onto the substrate surface in a zigzag motion. The vertical distance between the nozzle and the substrate is adjusted to 15 cm. The spraying is carried out slowly for 35 seconds at 0.5 MPa, and the spraying speed is 4 cm / s. After spraying, the superhydrophobic composite coating is obtained by drying and curing at room temperature for 24 hours.

[0041] The hydrophobicity test results of the superhydrophobic composite coating are as follows: Figure 1 As shown.

[0042] The microstructure of superhydrophobic coatings, such as Figure 9 As shown, the superhydrophobic coating exhibits a micro-nano papillary structure. The pores on the coating surface, combined with the micro-nano level surface protrusions, allow the coating to store a large amount of air to form a stable air layer. It is precisely due to the synergistic effect of epoxy resin and nanoparticles that a superhydrophobic surface with a micro-nano rough structure has been successfully established.

[0043] The abrasion resistance test results of the superhydrophobic composite coating are as follows: Figure 10As shown, the number of sandpaper abrasion cycles has a significant impact on the hydrophobicity of the coating. The contact angle (CA) decreases with increasing number of abrasion cycles. After 800 sandpaper abrasion cycles, the CA of the superhydrophobic coating decreases from 167.5° to 150.6°, while the roll-off angle increases from 2.5° to 24.7°. The coating still exhibits good superhydrophobicity, but the roll-off angle exceeds the required value. After more than 1200 abrasion cycles, the hydrophobicity of the sample decreases, with CA at 143.5° and SA at 33.2°. At this point, the contact angle is below 150°, and the coating no longer possesses superhydrophobicity, but it still exhibits good hydrophobicity.

[0044] The algae resistance test results of the superhydrophobic coating are as follows Figure 11 As shown, with increasing soaking time, Chlorella exhibited the highest adhesion of green algae on both the aluminum sheet and the ordinary E-51 epoxy resin coating. After 15 days of soaking, significant Chlorella adhesion was observed on both the aluminum sheet and the epoxy resin coating. After 30 days, the amount of Chlorella adhering to the surface increased significantly compared to the first 15 days, with the surface essentially covered by Chlorella. This is because a biofilm formed on the surface during the first 15 days provided nutrients for Chlorella adhesion, further accelerating the adhesion rate. In contrast, the superhydrophobic coating showed almost no algae adhesion after 15 days of soaking, and only a small amount of Chlorella adhered to the coating surface after 30 days.

[0045] Example 2: The preparation method of the superhydrophobic composite coating is as follows:

[0046] (1) 4g of epoxy resin (E-51) was uniformly dispersed into 45g of butyl acetate to obtain mixed solution A. The dispersion method was to first perform ultrasonic vibration dispersion with an ultrasonic power of 200W and a frequency of 50kHz for 10min, and then continuously stir at 600r / min for 120min.

[0047] (2) Add 3g of polyhexamethylene guanidine hydrochloride, 8g of polyvinylpyrrolidone, 40g of nano-TiO2 with a particle size of 40nm, 12g of polytetrafluoroethylene micro powder with a particle size of 2μm, 5g of graphene oxide and 0.5g of γ-aminopropyltriethoxysilane to mixed solution A, and then mix well to obtain mixed solution B.

[0048] (3) Add 0.4g of 1H,1H,2H,2H-perfluorooctyltriethoxysilane (POTS) and 3g of polyetheramine curing agent (D-230) to mixed solution B, and disperse evenly to obtain mixed solution C; the dispersion method is the same as step (1).

[0049] (4) Using a spray gun with a nozzle diameter of 0.7 mm, the mixed solution C was slowly sprayed onto the substrate surface in a zigzag motion. The vertical distance between the nozzle and the substrate was adjusted to 20 cm. Spraying was performed slowly for 45 seconds at 0.6 MPa, with a spraying speed of 2 cm / s. After spraying, the coating was allowed to dry and cure at room temperature for 30 hours to obtain the superhydrophobic composite coating. The hydrophobicity test results of the superhydrophobic composite coating are as follows: Figure 2 As shown.

[0050] Example 3: The preparation method of the superhydrophobic composite coating is as follows:

[0051] (1) 2g of epoxy resin (E-51) was uniformly dispersed into 25g of butyl acetate to obtain mixed solution A. The dispersion method was to first perform ultrasonic vibration dispersion with an ultrasonic power of 160W and a frequency of 30kHz for 30min, and then continuously stir at 200r / min for 30min.

[0052] (2) Add 2g of polyhexamethylene guanidine hydrochloride, 7g of polyvinylpyrrolidone, 20g of nano-TiO2 with a particle size of 20nm, 5g of polytetrafluoroethylene micro powder with a particle size of 1μm, 1g of graphene oxide and 0.15g of γ-aminopropyltriethoxysilane to mixed solution A, and then mix well to obtain mixed solution B.

[0053] (3) Add 0.3g of 1H,1H,2H,2H-perfluorooctyltriethoxysilane (POTS) and 1g of polyetheramine curing agent (D-230) to mixed solution B, and disperse evenly to obtain mixed solution C; the dispersion method is the same as step (1).

[0054] (4) Using a spray gun with a nozzle diameter of 0.3 mm, the mixed solution C was slowly sprayed onto the substrate surface in a zigzag motion. The vertical distance between the nozzle and the substrate was adjusted to 10 cm. Spraying was performed slowly for 30 seconds at a pressure of 0.4 MPa, with a spraying speed of 6 cm / s. After spraying, the coating was allowed to dry and cure at room temperature for 18 hours to obtain the superhydrophobic composite coating. The hydrophobicity test results of the superhydrophobic composite coating are as follows: Figure 3 As shown.

[0055] Example 4: Everything else is the same as in Example 1, except that:

[0056] In step (1), 8g of E-51 was dispersed into ethyl acetate to obtain mixed solution A.

[0057] In step (2), the amount of nano TiO2 used is 50g, the amount of polytetrafluoroethylene micro powder used is 10g, the amount of graphene oxide used is 10g, and the amount of KH550 used is 0.5g.

[0058] In step (3), the dosage of D-230 is 2.6g.

[0059] The hydrophobicity test results of the superhydrophobic composite coating are as follows: Figure 4 As shown.

[0060] Example 5: Everything else is the same as in Example 1, except that:

[0061] In step (1), methyl acetate is used instead of butyl acetate.

[0062] The hydrophobicity test results of the superhydrophobic composite coating are as follows: Figure 5 As shown.

[0063] Example 6: Everything else is the same as in Example 1, except that:

[0064] In step (1), phenyl acetate is used instead of butyl acetate.

[0065] The hydrophobicity test results of the superhydrophobic composite coating are as follows: Figure 6 As shown.

[0066] Example 7: Everything else is the same as in Example 1, except that:

[0067] In step (1), methyl benzoate is used to replace butyl acetate.

[0068] The hydrophobicity test results of the superhydrophobic composite coating are as follows: Figure 7 As shown.

[0069] Comparative Example 1: Everything else is the same as in Example 1, except that:

[0070] In step (2), polyhexamethylene guanidine hydrochloride and polyvinylpyrrolidone are not added.

[0071] The hydrophobicity test results of the composite coating are as follows: Figure 8 As shown.

[0072] Comparative Example 2: Everything else is the same as in Example 1, except that:

[0073] Polyhexamethylene guanidine hydrochloride is not added in step (2).

[0074] Comparative Example 3: Everything else is the same as in Example 1, except that:

[0075] No polyvinylpyrrolidone is added in step (2).

[0076] Comparative Example 4: Everything else is the same as in Example 1, except that:

[0077] The amount of nano-TiO2 added in step (2) is 8g.

[0078] Comparative Example 5: Everything else is the same as in Example 1, except that:

[0079] No graphene oxide is added in step (2).

[0080] The hydrophobic properties and inhibition properties against Chlorella adhesion of the coatings prepared in Examples 1-7 and Comparative Examples 1-3 were tested.

[0081] The method for detecting the inhibitory performance of the coating on Chlorella adhesion is as follows:

[0082] Chlorella suspension was inoculated into liquid algae culture medium at a ratio of 1%. Then, coated substrates were placed into the algae culture medium and cultured statically under light for 30 days. After 30 days, the substrates were removed, and the algae adhering to the coating surface were rinsed off. The rinsing liquid was collected by centrifugation, and the precipitate was weighed and the algae adhesion inhibition rate was calculated using the following formula:

[0083] Algal attachment inhibition rate (%) = (weight of sediment in blank control group - weight of sediment in experimental group) / weight of sediment in blank control group * 100%.

[0084] The blank control group consisted of untreated aluminum sheets.

[0085] Table 1. Contact angle and algae adhesion inhibition rate of different coatings

[0086] Group Contact angle (°) Algal attachment inhibition rate (%) Example 1 167.8±1.2° 98.2±1.3 Example 2 154.4±1.3° 97.4±1.1 Example 3 159.8±1.3° 95.8±3.2 Example 4 164.2±1.2° 97.6±2.8 Example 5 146.1±1.2° 97.8±2.5 Example 6 162.6±1.1° 96.9±2.9 Example 7 164.1±1.1° 97.2±2.2 Comparative Example 1 101.4±1.1° 98.0±1.6 Comparative Example 2 103.7±1.3° 98.4±1.1 Comparative Example 3 108.2±1.1° 97.9±1.8 Comparative Example 4 140.4±1.2° 36.4±3.3 Comparative Example 5 105.8±1.3° 97.8±1.3

[0087] As shown in Table 1, there was no significant difference in the inhibitory effect of Comparative Examples 1-5 and Example 1 on algae adhesion. However, the hydrophobic properties of Comparative Examples 1-3 were significantly lower than those of Example 1. This indicates that when polyhexamethylene guanidine hydrochloride and / or polyvinylpyrrolidone are absent, although titanium dioxide can inhibit algae adhesion, it also significantly inhibits the hydrophobic properties of the coating at this dosage. Polyhexamethylene guanidine hydrochloride and polyvinylpyrrolidone have a synergistic effect in improving the hydrophobic properties of titanium dioxide-containing coatings, giving the coating both superhydrophobic properties and algae adhesion inhibition properties.

[0088] In Comparative Example 4, the insufficient addition of titanium dioxide led to a significant reduction in algae suppression, but the impact on the hydrophobic properties of the coating was also relatively small.

[0089] In Comparative Example 5, the coating exhibited poor hydrophobicity due to the lack of graphene oxide, indicating that graphene oxide is a key component for improving superhydrophobicity in this invention.

Claims

1. A method for preparing a superhydrophobic composite coating, characterized in that, Includes the following steps: (1) Epoxy resin is uniformly dispersed into ester substances to obtain mixed solution A; (2) Add polyhexamethylene guanidine hydrochloride, polyvinylpyrrolidone, nano TiO2, polytetrafluoroethylene micro powder, graphene oxide and γ-aminopropyltriethoxysilane to mixed solution A, and mix well to obtain mixed solution B. (3) Add fluorosilane and polyetheramine curing agent to mixed solution B, and disperse evenly to obtain mixed solution C; (4) Spray the mixed solution C onto the substrate surface and dry it at room temperature to obtain the superhydrophobic composite coating.

2. The method for preparing the superhydrophobic composite coating according to claim 1, characterized in that, In step (2), the mass ratio of polyhexamethylene guanidine hydrochloride: polyvinylpyrrolidone: nano-TiO2: graphene oxide is 1-3: 2-8: 20-50: 2-10.

3. The method for preparing the superhydrophobic composite coating according to claim 1, characterized in that, The esters include at least one of butyl acetate, ethyl acetate, methyl acetate, phenyl acetate, and methyl benzoate; the fluorinated silane is 1H,1H,2H,2H-perfluorooctyltriethoxysilane.

4. The method for preparing the superhydrophobic composite coating according to claim 1, characterized in that, The epoxy resin is E-51, and the polyetheramine curing agent is D-230.

5. The method for preparing the superhydrophobic composite coating according to claim 1, characterized in that, The nano-TiO2 has a particle size of 20-40 nm, and the polytetrafluoroethylene micro powder has a particle size of 1-2 μm.

6. The method for preparing the superhydrophobic composite coating according to claim 1, characterized in that, The mass ratio of the epoxy resin to the polyetheramine curing agent is 2-4:1-3.

7. The method for preparing the superhydrophobic composite coating according to claim 1, characterized in that, In steps (1) and (3), the dispersion method is to first perform ultrasonic vibration dispersion and then continue stirring dispersion.

8. The method for preparing the superhydrophobic composite coating according to claim 7, characterized in that, The ultrasonic oscillation dispersion method is to use an ultrasonic power of 160-200W and a frequency of 30-50kHz for oscillation dispersion for 10-30 minutes; the stirring dispersion method is to stir at 200-600r / min for 30-120 minutes.

9. The method for preparing the superhydrophobic composite coating according to claim 1, characterized in that, In step (4), the mixed solution C is sprayed onto the substrate surface and dried at room temperature and ventilation. The method is as follows: spraying is carried out using a spray gun, adjusting the vertical distance between the nozzle of the spray gun and the substrate to 10-20cm, and spraying slowly for 30-45s at 0.4-0.6MPa with a spraying speed of 2-6cm / s.

10. The method for preparing the superhydrophobic composite coating according to claim 9, characterized in that, The nozzle diameter is 0.3-0.7 mm.

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