Preparation method of paint phenolic hydrophobic coating with micro-nano rough structure

Abstract

This invention discloses a method for preparing a urushiol-based hydrophobic coating with a micro / nano rough structure. The method uses urushiol and organic polyamines as main raw materials, and involves sequential prepolymerization and precipitation polymerization to construct a highly hydrophobic micro / nano rough structure surface coating on different substrates. This method utilizes renewable natural polymer materials as main raw materials, achieving highly hydrophobic modification of various materials without the need for chemical modifications such as silane modifiers. It is environmentally friendly, versatile, and allows for large-scale construction of micro / nano rough structure hydrophobic coatings using simple processes and mild conditions, significantly improving the efficiency of large-scale preparation of such functional coatings. This effectively solves the problems of low efficiency and high cost in existing methods for large-scale preparation of micro / nano rough structure hydrophobic surfaces.

Description

Technical Field

[0001] This invention belongs to the field of material functionalization, and specifically relates to a method for preparing a universal hydrophobic coating. Background Technology

[0002] Surface properties are among the most important physicochemical properties of materials, and many physicochemical processes are closely related to the surface characteristics of materials. Hydrophobic materials developed based on surface properties show broad application prospects in areas such as surface self-cleaning, anti-icing and anti-fogging, oil-water separation, and water-repellent and breathable textiles. Numerous studies have shown that simply reducing the surface energy of ordinary materials is insufficient to obtain highly hydrophobic surfaces; the design and construction of micron- and nano-scale rough structures on the material surface are essential for preparing highly hydrophobic materials. This is because the micro- and nano-scale rough structures on the material surface trap a large amount of air and form an air film at the solid-liquid interface, causing water droplets to suspend on surfaces with micro- and nano-scale rough structures and thus preventing wetting.

[0003] To construct micro / nano-structured rough surfaces on different materials, researchers both domestically and internationally have conducted numerous attempts. Currently, representative methods include template methods, surface etching methods, and surface deposition methods. Among these, the template method utilizes a material surface with micro / nano-rough structures as a substrate. An active polymer precursor is spread onto the substrate surface, cast, and cured to form a continuous whole. After demolding, a polymer template with a rough morphology opposite to the substrate is obtained, which is then used to prepare micro / nano surfaces of different materials. Although this method has relatively low requirements for equipment, it places extremely high demands on the precise replication of the micron and nano-scale fine structures of the substrate. Traditional template preparation processes still face significant technological difficulties and cost pressures in achieving nanoscale precision replication. Furthermore, this method often uses natural materials such as lotus leaves and inorganic porous materials such as porous alumina as substrate materials, which limits the controllability of the thickness and morphology of the micro / nano-structured layers. The surface etching method involves a top-down processing procedure to partially peel off the substrate material, forming a rough surface with a specific morphology. Currently, etching techniques used for fabricating highly hydrophobic surfaces mainly include photolithography, chemical etching, and plasma etching, with photolithography being the most widely studied. Compared to template methods, surface etching can directly construct more refined and regular micro / nano structures on the material surface according to a pre-designed pattern. Reported substrate materials include silicon wafers, metals, and glass, and with the addition of chemical modification with low surface energy materials such as fluorosilanes, various types of hydrophobic surfaces can be obtained. However, this method places high demands on processing equipment; achieving high etching precision often requires expensive equipment and harsh working environments. Although the rapid development of femtosecond laser technology in recent years has provided a relatively inexpensive and convenient photolithography method, efficiently and extensively fabricating micro / nano hierarchical surface structures on macroscopic objects using etching technology remains difficult. In contrast to etching, surface deposition is a bottom-up method for constructing surface morphology. It mainly forms a micro / nano hierarchical coating on the substrate material surface through methods such as vapor phase deposition, liquid phase deposition, hydrothermal growth, and electrochemical deposition. Since the deposited material can differ from the substrate material in terms of texture, structure, and properties, this method can be used to prepare highly hydrophobic surface materials with more complex and controllable structures and functions. However, this method often requires a relatively complex operation process and has high requirements for reaction conditions and process control. Moreover, apart from polydopamine, very few compounds can firmly adhere to the surface of different types of materials and gradually deposit to form a micro-nano rough structure layer. Furthermore, the strong hydrophilicity of dopamine itself means that this deposited coating needs to be chemically modified with hydrophobic modifiers, which further increases the complexity of the operation and the preparation cost. Summary of the Invention

[0004] To address the shortcomings of existing methods for preparing rough micro / nano structures in terms of equipment and condition requirements, efficiency and cost of large-scale preparation, process complexity, and material universality, this invention provides a novel method for constructing micro / nano rough hydrophobic layers on the surfaces of various materials in a simple, efficient, and low-cost manner. This method uses urushiol and organic polyamines as the main raw materials, and constructs hydrophobic coatings with micro / nano rough structures on the surfaces of different materials through prepolymerization combined with precipitation polymerization.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a urushiol-based hydrophobic coating with a micro-nano rough structure, comprising the following steps: 1) Add urushiol and organic polyamine to anhydrous ethanol and stir to dissolve them to form a precursor solution for the deposition reaction; 2) The substrate is immersed in the prepared deposition reaction precursor solution for prepolymerization reaction, so that urushiol undergoes self-polymerization; 3) After the reaction is completed, acid regulator is slowly added dropwise to the solution under continuous stirring to reduce the pH of the solution to 8-9, so as to carry out precipitation polymerization. During the copolymerization and crosslinking, due to the low solubility of the copolymer in the weak alkaline solution, the copolymer nanoparticles precipitate out of the solution and gradually adhere to and deposit on the substrate surface to form a micro-nano rough structure coating. 4) Remove the substrate treated in step 3) from the solution, rinse with anhydrous ethanol and dry to obtain a modified substrate with a highly hydrophobic micro-nano rough surface coating.

[0006] In the prepolymerization stage of this invention, the self-polymerization of urushiol is the main process. Simultaneously, due to the reducing properties of the catechol groups in urushiol, a small amount of urushiol is converted to quinone form under the influence of oxygen in ethanol and undergoes copolymerization with organic polyamines. The main product of this stage is oligomeric urushiol, which is soluble in ethanol and therefore does not precipitate. Subsequently, by adding an organic acid to lower the solution pH to 8-9, the self-polymerization of urushiol is inhibited, while the copolymerization of urushiol with amines increases. The organic polyamine undergoes copolymerization and crosslinking with the previously generated oligomeric urushiol. The resulting copolymer is insoluble in the weakly alkaline ethanol solution. As the degree of crosslinking increases and the solution pH decreases, it precipitates on the substrate surface, forming a hydrophobic coating with a micro-nano rough structure.

[0007] Furthermore, the viscosity of the urushiol mentioned in step 1) is greater than 1500 mPa•s.

[0008] Further, the organic polyamine mentioned in step 1) is one or more of the following compounds or polymers that are soluble in ethanol and contain two or more amine groups, such as hexamethylenediamine, diethylenetriamine, triethylenetetramine, and polyethyleneimine.

[0009] Further, by weight, step 1) uses 100 parts of anhydrous ethanol, 1.2-1.8 parts of urushiol, and 0.2-1.2 parts of organic polyamine.

[0010] Furthermore, the substrate in step 2) includes inorganic materials such as glass and ceramics, polymer materials such as plastics and chemical fibers, and natural materials such as cotton, linen, paper, and wood.

[0011] Furthermore, the temperature of the prepolymerization reaction in step 2) is 15-35℃, and the time is 1-2h.

[0012] Further, the acid regulator in step 3) is an organic acid such as acetic acid or citric acid.

[0013] Furthermore, the precipitation polymerization time in step 3) is 1-4 hours.

[0014] Further, in step 4), the drying temperature is 60°C and the time is 1 hour.

[0015] This invention first utilizes the solubility of urushiol in ethanol to extract urushiol from raw lacquer as a reaction raw material; then, urushiol and organic polyamine are added to anhydrous ethanol to prepare a deposition reaction precursor solution; the substrate is then immersed in the deposition reaction precursor solution, and the urushiol in the deposition reaction precursor solution undergoes self-polymerization to form oligomeric urushiol by utilizing the base catalysis of the organic polyamine. At the same time, it will also slowly undergo a Schiff base reaction with the organic polyamine to undergo binary copolymerization; after the reaction has proceeded for a period of time, by slowly adding an acid regulator to the solution and continuously stirring, the self-polymerization of urushiol can be inhibited and its copolymerization and cross-linking reaction with the amine can be promoted to form a copolymer product insoluble in ethanol. At the same time, the decrease in the pH value of the solution further reduces the solubility of the copolymer product in the solution, promoting its precipitation and simultaneously achieving morphology control of the copolymer product nanoparticles, so that the precipitate gradually adheres and deposits on the substrate surface to form a micro-nano rough structure coating; finally, by removing the substrate, cleaning and drying it, the reaction is promoted to be complete, and a modified substrate with a micro-nano rough structure surface coating with high hydrophobic properties is obtained.

[0016] The significant advantages of this invention are: First, the present invention immerses the substrate to be treated in a deposition reaction precursor solution, and forms a micro-nano rough structure coating with a micron-scale continuous skeleton and nano-scale spherical protrusions on the substrate surface by means of precipitation polymerization and adhesion deposition. The preparation process is short and the reaction conditions are mild. It can complete the surface modification of a large area of ​​material in one go without complex and expensive equipment and harsh reaction conditions, effectively solving the problems of low efficiency and high cost of existing methods when preparing micro-nano rough hydrophobic surfaces on a large scale.

[0017] Secondly, this invention only requires the preparation of a simple deposition precursor solution, which can be used in a reaction vessel to perform steps such as copolymerization of urushiol-polyamine, precipitation of nanoparticles, and adhesion deposition on the substrate surface of different types of materials in a "one-pot" process. There is no need to switch other reaction systems and reaction vessels during the process, and the microstructure of the deposited coating can be easily controlled by the pH of the solution. After deposition, no chemical modification such as silane modification is required to achieve a high hydrophobic effect, which solves the problems of complex process and high operation requirements of existing methods.

[0018] Third, the main raw material urushiol used in this invention contains a large number of catechol groups, which can firmly adhere to the surface of various types of materials, and has stronger substrate universality than existing methods. Attached Figure Description

[0019] Figure 1 This is a reaction mechanism diagram of the micro / nano rough structure coating constructed by urushiol-organic polyamine in this invention.

[0020] Figure 2 The image shows a sample of the urushiol-triethylenetetramine (pH=9) deposition-modified filter paper prepared in Example 1, along with its water contact angle and surface SEM image.

[0021] Figure 3 The image shows a sample of the urushiol-triethylenetetramine (pH=8.5) deposition-modified filter paper prepared in Example 2, along with its water contact angle and surface SEM image.

[0022] Figure 4 The image shows a sample of the urushiol-triethylenetetramine (pH=8) deposition-modified filter paper prepared in Example 3, along with its water contact angle and surface SEM image.

[0023] Figure 5 The images show the sample, water contact angle, and surface SEM image of the urushiol-diethylenetriamine (pH=8) deposition-modified polyester nonwoven fabric prepared in Example 4.

[0024] Figure 6 The image shows a sample of the urushiol-hexanediamine (pH=8) deposition-modified glass slide prepared in Example 5, along with its water contact angle and surface SEM image.

[0025] Figure 7 The infrared and XPS spectra of the urushiol-hexamethylenediamine copolymer deposit obtained in Example 5 are shown.

[0026] Figure 8 The image shows a sample of the urushiol-polyethyleneimine (pH=8) deposition-modified cotton fabric prepared in Example 6, along with its water contact angle and surface SEM image.

[0027] Figure 9 The images show the sample image, water contact angle, and surface SEM image of the urushiol-hexamethylenediamine thermosetting modified glass slide prepared in Example 1.

[0028] Figure 10 The images show the sample image, water contact angle, and surface SEM image of the urushiol-hexanediamine modified glass slide prepared in a mixed solvent of ethanol and water, which is a control example 2. Detailed Implementation

[0029] A method for preparing an urushiol-based hydrophobic material with a micro / nano rough structure includes the following steps: 1) Add raw lacquer to anhydrous ethanol at a volume ratio of 5:1, stir thoroughly to dissolve urushiol in the raw lacquer in ethanol, let stand and separate into layers, then remove the ethanol from the urushiol ethanol solution by rotary evaporation to obtain purified urushiol. After stirring continuously until the viscosity is greater than 1500 mPa•s, transfer it to a container and seal it for storage. 2) By weight, add 1.2-1.8 parts of urushiol and 0.2-1.2 parts of organic polyamine to 100 parts of anhydrous ethanol, stir and dissolve to form a precursor solution for the deposition reaction; 3) Immerse the substrate in the prepared deposition reaction precursor solution and prepolymerize it at 15-35℃ for 1-2 hours to allow urushiol to undergo self-polymerization; 4) After the reaction is completed, acid regulator is slowly added dropwise to the solution under continuous stirring to reduce the pH of the solution to 8-9, and the precipitation polymerization is carried out for 1-4 hours. At the same time, the change in pH value causes the copolymer nanoparticles to precipitate from the solution and gradually adhere to and deposit on the substrate surface to form a micro-nano rough structure coating. 5) Remove the substrate treated in step 4) from the solution, rinse with anhydrous ethanol and dry at 60°C for 1 hour to allow the deposit to react completely, and obtain a modified substrate with a highly hydrophobic micro-nano rough surface coating.

[0030] The organic polyamine is one or more compounds or polymers that are soluble in ethanol and contain two or more amine groups, such as hexamethylenediamine, diethylenetriamine, triethylenetetramine, and polyethyleneimine. The substrate includes inorganic materials such as glass and ceramics, polymeric materials such as plastics and synthetic fibers, and natural materials such as cotton, linen, paper, and wood. The acid regulator is an organic acid such as acetic acid or citric acid.

[0031] To make the content of this invention easier to understand, the technical solution of this invention will be further described below with reference to specific embodiments, but this invention is not limited thereto.

[0032] Example 1 (1) Add 100 mL of raw lacquer to 500 mL of anhydrous ethanol and stir thoroughly to dissolve the urushiol in the raw lacquer in the ethanol. After standing and separating into layers, remove the ethanol from the urushiol ethanol solution by rotary evaporation. Place the purified urushiol in a container and stir continuously until its viscosity reaches 1800 mPa·s. Then transfer it to a container and seal it for storage.

[0033] (2) Add 1.2g urushiol and 0.4g triethylenetetramine to 100mL of anhydrous ethanol, stir and dissolve to prepare a sedimentation reaction precursor solution.

[0034] (3) Place the sedimentation reaction precursor solution in a petri dish, immerse the qualitative filter paper in the sedimentation reaction precursor solution, seal the container opening with plastic wrap with small holes, then place the petri dish in a 15°C oven for 2 hours, and add acetic acid to the sedimentation solution dropwise to adjust the pH of the solution to 9 under constant stirring. After the addition is completed, continue the reaction and sedimentation for 2 hours.

[0035] (4) Take out the treated filter paper, rinse it with anhydrous ethanol, and dry it in an oven at 60°C for 1 hour to allow the sediment to react completely.

[0036] like Figure 2 As can be seen, due to the high pH value in this embodiment, the self-polymerization reaction of urushiol plays a dominant role in the reaction, and the low degree of cross-linking of the product results in high solubility. As a result, the filter paper surface is covered with an amorphous coating formed by the large-area bonding of urushiol and triethylenetetramine. Although the coating has a bonding layer with a length of 5-8 μm and spherical protrusions with a diameter of about 800 nm, it only has preliminary micro-nano rough structure characteristics. Therefore, its hydrophobicity is moderate and the water contact angle is 121°.

[0037] Example 2 (1) Add 100 mL of raw lacquer to 500 mL of anhydrous ethanol and stir thoroughly to dissolve the urushiol in the raw lacquer in the ethanol. After standing and separating into layers, remove the ethanol from the urushiol ethanol solution by rotary evaporation. Place the purified urushiol in a container and stir continuously until its viscosity reaches 1800 mPa·s. Then transfer it to a container and seal it for storage.

[0038] (2) Add 1.2g urushiol and 0.4g triethylenetetramine to 100mL of anhydrous ethanol, stir and dissolve to prepare a sedimentation reaction precursor solution.

[0039] (3) Place the sedimentation reaction precursor solution in a petri dish, immerse the qualitative filter paper in the sedimentation reaction precursor solution, seal the container opening with plastic wrap with small holes, and then place the petri dish in a 15°C oven for 2 hours. Under continuous stirring, add acetic acid to the sedimentation solution to adjust the pH of the solution to 8.5. After the addition is completed, continue the reaction and sedimentation for 2 hours.

[0040] (4) Take out the treated filter paper, rinse it with anhydrous ethanol, and dry it in an oven at 60°C for 1 hour to allow the sediment to react completely.

[0041] like Figure 3As can be seen, in this embodiment, the proportion of the copolymerization reaction of urushiol-amine increases due to the decrease of pH to 8.5, and the increased degree of cross-linking of the product leads to lower solubility. Therefore, the filter paper surface is coated with a small amount of bonded coral-like coating formed by the deposition of urushiol-triethylenetetramine. This coating consists of a 3-4 μm long bonded layer and a large number of spherical protrusions with a diameter of about 500-600 nm, which have obvious micro-nano rough structure characteristics. Therefore, it has strong hydrophobicity and a water contact angle of 132°.

[0042] Example 3 (1) Add 100 mL of raw lacquer to 500 mL of anhydrous ethanol and stir thoroughly to dissolve the urushiol in the raw lacquer in the ethanol. After standing and separating into layers, remove the ethanol from the urushiol ethanol solution by rotary evaporation. Place the purified urushiol in a container and stir continuously until its viscosity reaches 1800 mPa·s. Then transfer it to a container and seal it for storage.

[0043] (2) Add 1.2g urushiol and 0.4g triethylenetetramine to 100mL of anhydrous ethanol, stir and dissolve to prepare a sedimentation reaction precursor solution.

[0044] (3) Place the sedimentation reaction precursor solution in a petri dish, immerse the qualitative filter paper in the sedimentation reaction precursor solution, seal the container opening with plastic wrap with small holes, and then place the petri dish in a 15°C oven for 2 hours. Under continuous stirring, add acetic acid to the sedimentation solution to adjust the pH of the solution to 8. After the addition is completed, continue the reaction and sedimentation for 2 hours.

[0045] (4) Take out the treated filter paper, rinse it with anhydrous ethanol, and dry it in an oven at 60°C for 1 hour to allow the sediment to react completely.

[0046] like Figure 4 As can be seen, in this embodiment, the copolymerization reaction plays a dominant role in the reaction due to the pH being reduced to 8. The high degree of cross-linking of the product results in very low solubility. Therefore, a coral-like coating formed by the deposition of urushiol-triethylenetetramine is obtained on the surface of the filter paper. This coating consists of a coral-like skeleton with a length of 2-3 μm and a large number of spherical protrusions with a diameter of 300-400 nm. It has obvious micro-nano rough structure characteristics, so it has strong hydrophobicity and a water contact angle of up to 144°.

[0047] Example 4 (1) Add 100 mL of raw lacquer to 500 mL of anhydrous ethanol and stir thoroughly to dissolve the urushiol in the raw lacquer in the ethanol. After standing and separating into layers, remove the ethanol from the urushiol ethanol solution by rotary evaporation. Place the purified urushiol in a container and stir continuously until its viscosity reaches 1600 mPa·s. Then transfer it to a container and seal it for storage.

[0048] (2) Add 1.2g urushiol and 1.2g diethylenetriamine to 100mL of anhydrous ethanol, stir and dissolve to prepare a sedimentation reaction precursor solution.

[0049] (3) Place the sedimentation reaction precursor solution in a petri dish, immerse the polyester nonwoven fabric in the sedimentation reaction precursor solution, seal the container opening with plastic wrap with small holes, then place the petri dish in a 25°C oven for 1 hour, and add acetic acid to the sedimentation solution dropwise to adjust the pH of the solution to 8 under constant stirring. After the addition is completed, continue the reaction and sedimentation for 4 hours.

[0050] (4) Take out the treated polyester nonwoven fabric, rinse it with anhydrous ethanol, and dry it in an oven at 60°C for 1 hour to allow the deposits to react completely.

[0051] like Figure 5 As can be seen, in this embodiment, the low pH value makes the copolymerization reaction play a dominant role in the reaction, and the high degree of cross-linking of the product results in very low solubility. Therefore, the nonwoven fabric surface is obtained with a coral-like coating formed by the deposition of urushiol-diethylenetriamine. This coating consists of a coral-like skeleton with a length of 3-4 μm and a large number of spherical protrusions with a diameter of 400-500 nm. It has obvious micro-nano rough structure characteristics, so it has strong hydrophobicity and a water contact angle of up to 141°.

[0052] Example 5 (1) Add 100 mL of raw lacquer to 500 mL of anhydrous ethanol and stir thoroughly to dissolve the urushiol in the raw lacquer in the ethanol. After standing and separating into layers, remove the ethanol from the urushiol ethanol solution by rotary evaporation. Place the purified urushiol in a container and stir continuously until its viscosity reaches 1900 mPa·s. Then transfer it to a container and seal it for storage.

[0053] (2) Add 1.8g urushiol and 0.6g hexamethylenediamine to 100mL of anhydrous ethanol, stir and dissolve to prepare a sedimentation reaction precursor solution.

[0054] (3) Place the sedimentation reaction precursor solution in a petri dish, immerse the glass slide in the sedimentation reaction precursor solution, seal the container opening with plastic wrap with small holes, and then place the petri dish in a 35°C oven for 1.5 hours. Under constant stirring, add citric acid to the sedimentation solution to adjust the pH of the solution to 8. After the addition is completed, continue the reaction and sedimentation for 3 hours.

[0055] (4) Take out the treated glass slide, rinse it with anhydrous ethanol and dry it in an oven at 60°C for 1 hour to allow the deposit to react completely.

[0056] like Figure 6As can be seen, in this embodiment, the low pH value makes the copolymerization reaction play a dominant role in the reaction, and the high degree of cross-linking of the product results in very low solubility. Therefore, the surface of the glass slide is coated with a coral-like coating formed by the deposition of urushiol-hexanediamine. This coating consists of a coral-like skeleton with a length of 4-6 μm and a large number of spherical protrusions with a diameter of 400-600 nm. It has obvious micro-nano rough structure characteristics, so it has strong hydrophobicity and a water contact angle of 129°.

[0057] Figure 7 The figures show the infrared and XPS spectra of the obtained urushiol-hexanediamine copolymer deposit. As can be seen from the figures, compared to pure urushiol, the copolymer exhibits a higher infrared spectrum at 1520 cm⁻¹. -1 An imine absorption peak at C=N appears at 1590 cm⁻¹. -1 The enhanced CN absorption peak indicates that urushiol and hexamethylenediamine underwent binary copolymerization via a Schiff base reaction. Simultaneously, the XPS spectrum of the copolymer also showed a C=N / CN absorption peak, while pure urushiol contains only C, H, and O elements and no N element, further confirming the occurrence of the copolymerization reaction.

[0058] Example 6 (1) Add 100 mL of raw lacquer to 500 mL of anhydrous ethanol and stir thoroughly to dissolve the urushiol in the raw lacquer in the ethanol. After standing and separating into layers, remove the ethanol from the urushiol ethanol solution by rotary evaporation. Place the purified urushiol in a container and stir continuously until its viscosity reaches 2000 mPa·s. Then transfer it to a container and seal it for storage.

[0059] (2) Add 1.8g urushiol and 0.2g polyethyleneimine to 100mL of anhydrous ethanol, stir and dissolve to prepare a sedimentation reaction precursor solution.

[0060] (3) Place the sedimentation reaction precursor solution in a petri dish, soak cotton cloth in the sedimentation reaction precursor solution, seal the container opening with plastic wrap with small holes, and then place the petri dish in a 35°C oven for 2 hours. Under continuous stirring, add acetic acid to the sedimentation solution to adjust the pH of the solution to 8. After the addition is completed, continue the reaction and sedimentation for 1 hour.

[0061] (4) Take out the treated cotton cloth, rinse it with anhydrous ethanol, and dry it in an oven at 60°C for 1 hour to allow the sediment to react completely.

[0062] like Figure 8 As can be seen, in this embodiment, the low pH value makes the copolymerization reaction play a dominant role in the reaction, and the high degree of cross-linking of the product results in very low solubility. Therefore, the surface of the cotton fabric is coated with a coral-like coating formed by the deposition of urushiol-polyethyleneimine. This coating consists of a coral-like skeleton with a length of 2-3 μm and a large number of spherical protrusions with a diameter of 300-500 nm. It has obvious micro-nano rough structure characteristics, so it has strong hydrophobicity and a water contact angle of up to 143°.

[0063] Compare with Example 1 (1) Add 100 mL of raw lacquer to 500 mL of anhydrous ethanol and stir thoroughly to dissolve the urushiol in the raw lacquer in the ethanol. After standing and separating into layers, remove the ethanol from the urushiol ethanol solution by rotary evaporation. Place the purified urushiol in a container and stir continuously until its viscosity reaches 1900 mPa·s. Then transfer it to a container and seal it for storage.

[0064] (2) Add 10 mL of anhydrous ethanol, 1.8 g of urushiol and 0.6 g of hexamethylenediamine to a beaker and stir to prepare a urushiol-hexamethylenediamine mixed solution.

[0065] (3) The mixed solution is coated on the surface of the glass slide and placed in an oven at 120°C for 24 hours to dry and cure, thus obtaining a glass slide modified with urushiol-hexamethylenediamine with a dense and flat surface structure.

[0066] like Figure 9 As can be seen, in this comparative example, due to the use of a mixed solution coating method for drying and curing, it is impossible to obtain a micro-nano rough structure coating, but only a dense and flat micro-surface morphology can be obtained, and its water contact angle is only 90°.

[0067] Compare with Example 2 (1) Add 100 mL of raw lacquer to 500 mL of anhydrous ethanol and stir thoroughly to dissolve the urushiol in the raw lacquer in the ethanol. After standing and separating into layers, remove the ethanol from the urushiol ethanol solution by rotary evaporation. Place the purified urushiol in a container and stir continuously until its viscosity reaches 1900 mPa·s. Then transfer it to a container and seal it for storage.

[0068] (2) Add 8 mL of anhydrous ethanol, 2 mL of deionized water, 1.8 g of urushiol and 0.6 g of hexamethylenediamine to a beaker and stir to prepare a urushiol-hexamethylenediamine mixed solution.

[0069] (3) The mixed solution is coated on the surface of the glass slide and placed in an oven at 120°C for 24 hours to dry and cure, thus obtaining a glass slide modified with urushiol-hexamethylenediamine with a dense surface structure.

[0070] like Figure 10 It is evident that although the introduction of water can cause a certain change in the solubility of the reactants when they are dried, it can only form wrinkles on a macroscopic scale and cannot produce a micro-nano rough surface structure. Its water contact angle is only 92°.

[0071] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A method for preparing a urushiol-based hydrophobic coating with a micro / nano rough structure, characterized in that, Includes the following steps: 1) Add urushiol and organic polyamine to anhydrous ethanol and stir to dissolve them to form a precursor solution for the deposition reaction; 2) The substrate is immersed in the prepared deposition reaction precursor solution for prepolymerization reaction; 3) After the reaction is completed, an acid regulator is added under continuous stirring to lower the pH of the solution to 8-9 for precipitation polymerization, so that the copolymer nanoparticles precipitate out of the solution and gradually adhere to and deposit on the substrate surface to form a micro-nano rough structure coating. 4) Remove the substrate treated in step 3) from the solution, rinse with anhydrous ethanol and dry to obtain a modified substrate with a highly hydrophobic micro-nano rough surface coating. The organic polyamine is one or more compounds or polymers that are soluble in ethanol and contain two or more amine groups.

2. The method for preparing the urushiol-based hydrophobic coating with a micro-nano rough structure according to claim 1, characterized in that, By weight, step 1) uses 100 parts anhydrous ethanol, 1.2-1.8 parts urushiol, and 0.2-1.2 parts organic polyamine.

3. The method for preparing the urushiol-based hydrophobic coating with a micro / nano rough structure according to claim 1 or 2, characterized in that, The viscosity of the urushiol is greater than 1500 mPa•s.

4. The method for preparing the urushiol-based hydrophobic coating with a micro / nano rough structure according to claim 1, characterized in that, The temperature of the prepolymerization reaction in step 2) is 15-35℃, and the time is 1-2h.

5. The method for preparing the urushiol-based hydrophobic coating with a micro-nano rough structure according to claim 1, characterized in that, Step 3) The acid regulator is an organic acid.

6. The method for preparing the urushiol-based hydrophobic coating with a micro / nano rough structure according to claim 1, characterized in that, Step 3) The precipitation polymerization time is 1-4 hours.

7. The method for preparing the urushiol-based hydrophobic coating with a micro / nano rough structure according to claim 1, characterized in that, Step 4) The drying temperature is 60℃ and the time is 1 hour.

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