Superhydrophobic wood, preparation method thereof, and composite suspension

Abstract

The present invention relates to the field of functional wood materials, and discloses a super-hydrophobic wood, a preparation method thereof, and a composite suspension. The components of the composite suspension include nano-hydroxyapatite, polydimethylsiloxane, ethyl acetate, and a curing agent. The preparation method of the super-hydrophobic wood comprises the following steps: subjecting the wood to an alkali etching treatment; spraying the composite suspension on the surface of the wood, and obtaining the super-hydrophobic wood after curing. The super-hydrophobic wood prepared by the present invention has excellent water-repellent properties, and its water contact angle can reach 153.3°. At the same time, the rolling angle is small, only 4.3°, and is suitable for wood applications in outdoor environments. After 60 days of outdoor exposure, the water contact angle can still be maintained at 152.5°, and the rolling angle is about 6.1°, which proves that the coating has good weather resistance. After multiple wear and repair cycles, the water contact angle can still be restored to 142°, and the repair rate is as high as 92.4%.

Description

Technical Field

[0001] The present invention relates to the field of wood functional materials, and more particularly to super-hydrophobic wood, a preparation method thereof, and a composite suspension. Background Art

[0002] Wood is one of the most abundant biomaterials in the world, boasting advantages such as high mechanical strength and strong biodegradability. It is widely used in furniture, construction, and other fields. However, due to its porous structure and hydrophilic groups, wood readily absorbs water in humid environments, causing deformation and other problems that seriously affect the durability of wooden products. To address this issue, researchers have proposed modifying wood to be superhydrophobic, reducing its hydrophilicity and mitigating cracking and deformation caused by shrinkage and swelling, thereby extending the service life of wooden products.

[0003] At present, existing research methods mainly introduce inorganic nanoparticles on the wood surface through impregnation, in-situ generation and other methods to construct micro-nano rough structures, and then achieve superhydrophobic modification by modifying low surface energy materials. Although these methods have been successful in improving the hydrophobic properties of wood, they still face several challenges: the preparation process is complicated and the cost is high, making it difficult to achieve industrial production; some treatment materials are biotoxic and have adverse effects on the environment or human body; most methods can only achieve superhydrophobic modification on the cross section of wood, while the tangential section of wood is more exposed in actual use, but existing technologies are difficult to apply on this surface. In addition, existing superhydrophobic coatings have poor stability and are easily affected by mechanical damage or chemical corrosion, resulting in the loss of their waterproof properties.

[0004] Prior art CN201510260258.X produces super-hydrophobic wood by vapor-depositing vinyltriethoxysilane and nanoparticles onto the surface of wood. However, vapor deposition requires expensive equipment, is complex, and is costly. It is also incapable of coating large or complex substrates, and exhibits a slow deposition rate and a long deposition time. The resulting super-hydrophobic wood is unsuitable for outdoor use, and the coating is difficult to restore after damage.

[0005] Therefore, there is an urgent need for a simple, low-cost, long-lasting superhydrophobic modification method that can be applied to the tangential section of wood to improve the durability of wood and broaden its application range in practical environments. Summary of the Invention

[0006] The present invention provides a super-hydrophobic wood to overcome the defects of the prior art, such as expensive equipment, complicated operation, high cost, inability to prepare large-area or complex-shaped substrates, long preparation time, and difficulty in recovering the coating after damage.

[0007] Another object of the present invention is to provide a method for preparing super-hydrophobic wood;

[0008] Another object of the present invention is to provide a composite suspension.

[0009] In order to solve the above technical problems, the technical solutions of the present invention are as follows:

[0010] A method for preparing super-hydrophobic wood comprises the following steps:

[0011] S1: alkaline etching treatment of wood;

[0012] S2: A composite suspension containing nano-hydroxyapatite (HAP), polydimethylsiloxane (PDMS), ethyl acetate and a curing agent is treated on the wood surface, and superhydrophobic wood is obtained after curing.

[0013] The present invention innovatively uses PDMS, a highly flexible material, on the wood surface, forming a uniform, continuous film. The resulting super-hydrophobic wood coating can withstand a certain degree of mechanical damage without cracking or flaking when the wood is subjected to stress, deformation, or external impact. PDMS enables the super-hydrophobic wood of the present invention to repair minor damage through molecular chain rearrangement and migration, allowing the super-hydrophobic coating to be repaired multiple times, significantly extending the coating's service life and effectiveness.

[0014] This invention innovatively leverages the inorganic properties of HAP, resulting in a highly stable wood surface that resists degradation or significant chemical changes under a wide range of environmental conditions. The HAP surface is rich in hydroxyl groups, providing active sites for binding to PDMS molecules. On alkaline-etched wood surfaces, HAP nanoparticles can form stronger physical adsorption or chemical bonds with wood active sites (such as exposed hydroxyl groups on the wood surface) through their surface hydroxyl groups, thereby enhancing the adhesion and stability of the PDMS coating.

[0015] At the same time, the micro-nanostructure of HAP particles increases the surface roughness, while PDMS, as a low surface energy material, further reduces the interaction between water and the surface. This synergistic effect not only increases the surface contact angle but also makes the coating more stable and durable.

[0016] Preferably, the polydimethylsiloxane is a polydimethylsiloxane prepolymer.

[0017] Preferably, the nano-hydroxyapatite is hydroxyapatite nanospheres with a diameter of 10 to 100 nm.

[0018] Preferably, the mass ratio of the curing agent to the polydimethylsiloxane prepolymer is 1:10.

[0019] Preferably, the curing agent includes a condensation-type curing agent and an addition-reaction-type curing agent, including ethoxysilane, methoxysilane, and silicon hydrogen siloxane.

[0020] Preferably, the composite suspension is sprayed on the wood surface at a distance of 30 to 50 cm from the wood surface.

[0021] Preferably, the curing temperature in S2 is 20°C to 150°C.

[0022] Preferably, the curing in S2 can be performed at room temperature (20° C. to 25° C.).

[0023] Preferably, the curing time in S2 is 0.1 to 12 hours.

[0024] Furthermore, the mass ratio of ethyl acetate to nano-hydroxyapatite is 400-600:1.

[0025] Preferably, the mass ratio of ethyl acetate to nano-hydroxyapatite is 500:1.

[0026] Furthermore, in the composite suspension described in S2, the mass ratio of nano-hydroxyapatite to polydimethylsiloxane prepolymer is 1:8-20.

[0027] Preferably, in the composite suspension described in S2, the mass ratio of nano-hydroxyapatite to polydimethylsiloxane prepolymer is 1:10-15.

[0028] Furthermore, during the alkali etching treatment in S1, the wood is immersed in an alkali solution with a concentration of 0.1 to 1 wt%.

[0029] Preferably, the concentration of the alkaline solution is 0.5 wt%.

[0030] Furthermore, during the alkaline etching treatment in S1, the wood is immersed in an alkaline solution for 1 to 2 hours.

[0031] Preferably, the soaking time is 2 hours.

[0032] Preferably, after soaking in the alkaline solution, the wood surface is washed with deionized water and dried at 25-103°C.

[0033] Furthermore, the amount of the composite suspension in S2 added to the wood surface is 0.8 to 1.2 g / cm 2 .

[0034] Preferably, the composite suspension is sprayed on the wood surface at a distance of 30 to 50 cm from the wood.

[0035] Furthermore, the wood surface in S2 includes a transverse section, a tangential section, and a radial section.

[0036] Super-hydrophobic wood is prepared by the preparation method.

[0037] Furthermore, after being damaged, the super-hydrophobic coating can be restored at a temperature above 80°C and below 120°C.

[0038] Preferably, recovery is at 100°C.

[0039] A composite suspension is used for preparing the super-hydrophobic wood, and its components include nano-hydroxyapatite, polydimethylsiloxane, ethyl acetate and a curing agent.

[0040] Preferably, the composite suspension can be applied to the wood surface including the cross section, tangential section and radial section.

[0041] Preferably, the composite suspension is prepared by the following method: adding nano-hydroxyapatite to ethyl acetate, then adding polydimethylsiloxane and a curing agent, and dispersing to obtain a composite suspension.

[0042] This invention creates a stable superhydrophobic system on the tangential section of wood through a dual mechanism of alkaline etching and composite coating. The alkaline etching provides a foundation of roughness and active sites, while the HAP nanoparticles further enhance the surface micro- and nanostructures. The low surface energy of PDMS effectively reduces the surface's hydrophilicity. This combination creates a high contact angle for water droplets on the wood surface, with an extremely low rolling angle, achieving excellent superhydrophobicity and self-cleaning properties.

[0043] When the coating is worn, PDMS is thermoresponsive, allowing it to reflow and cover the damaged area under heating conditions. HAP, as a stable nanoparticle, provides a support framework, allowing PDMS to quickly fill the damaged area and restore the coating's integrity and hydrophobicity. In contrast, particles such as SiO2 and TiO2, when combined with PDMS, often fail to achieve similar self-healing properties due to their weak surface chemistry or unstable structure.

[0044] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0045] 1. Significantly improved superhydrophobicity: Through the synergistic effect of alkaline etching treatment and nano-hydroxyapatite (HAP) composite suspension, a highly rough micro-nano structure is formed on the wood surface, which significantly improves the water contact angle (up to 153.3°) and has a small rolling angle (less than 5°), demonstrating excellent superhydrophobic properties and making it suitable for wood applications in outdoor environments.

[0046] 2. Strong coating stability: After wood was subjected to harsh environmental tests such as tape stripping, water shock, chemical corrosion, UV irradiation, and freeze-thaw cycles, its superhydrophobic properties remained stable, with almost no noticeable change in the contact angle. This demonstrates that the coating is firmly bonded to the substrate, can withstand mechanical and chemical damage in a variety of environments, and is suitable for long-term use. After 60 days of outdoor exposure, the superhydrophobic coating maintained a water contact angle of 152.5° and a rolling angle of approximately 6.1°, demonstrating its excellent weather resistance and suitability for long-term outdoor use.

[0047] 3. Outstanding self-repairing ability: Within the repair temperature range, the super-hydrophobic coating on the wood surface has good self-repairing ability, especially at 100°C. After multiple wear and repair cycles, the water contact angle can still be restored to 142°, with a repair rate of up to 92.4%, effectively extending the service life of the coating.

[0048] 4. No adverse effect on mechanical properties: Alkali etching treatment did not significantly reduce the bending strength and compressive strength of wood, verifying that this modification method maintains the original mechanical properties of wood while enhancing the surface properties of wood, ensuring structural safety in practical applications.

[0049] 5. Environmental protection and cost-effectiveness: The composite suspension used in the present invention has low toxicity and a simple process, which avoids the need for expensive equipment such as complex vapor deposition, has good prospects for industrial production, and reduces potential harm to the environment and human body. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 is a scanning electron micrograph of the hydroxyapatite nanospheres in Example 1;

[0051] Figure 2 This is a water contact angle test diagram of wood surface coating;

[0052] Figure 3 Data graph of water contact angle and rolling angle of wood surface coating;

[0053] Figure 4 The three-dimensional contour map of the wood surface, a is natural wood, b is wood after alkali etching treatment;

[0054] Figure 5 The water contact angle test diagram of wood surface coating under different alkali treatment conditions, a is different sodium hydroxide concentration, b is different immersion time;

[0055] Figure 6 The water contact angle test diagram of wood surface coating with different nanoparticles added;

[0056] Figure 7a~f are water contact angle test graphs of Example 1 after tape stripping, water impact, chemical corrosion, UV irradiation, freeze-thaw cycles, and outdoor exposure, respectively; g~h are flexural strength and compressive strength after alkali treatment, respectively;

[0057] Figure 8 Results of multiple wear-repair experiments on wood superhydrophobic coatings at different temperatures, a~e are the effects of repair temperature on contact angle, f~i are the changes in repair rate, h~i are the repair rate and water contact angle at 100°C, respectively;

[0058] Figure 9 This is the water contact angle test diagram of the coating on the cross section of wood. DETAILED DESCRIPTION

[0059] The present invention will be further described below in conjunction with the accompanying drawings and specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0060] Unless otherwise specified, the reagents and materials used in the following examples are commercially available. TM 184.

[0061] Example 1

[0062] The tangential section of the wood was polished with sandpaper and washed with 75% ethanol and pure water. The treated wood was then soaked in a 0.5wt% NaOH solution for 2 h, and the residual NaOH on the wood surface was washed with deionized water. The wood was then dried in a 103°C oven for 6 h before use. 0.08g of HAP was added to 40g of ethyl acetate, followed by 0.8g of polydimethylsiloxane prepolymer and 0.08g of curing agent. The mixture was ultrasonically dispersed for 30 min to prepare a composite suspension. The prepared composite suspension was then heated to 1 g / cm 2 The amount of the solvent was sprayed on the polished surface of the wood at a distance of 30 to 50 cm from the wood, and then dried in an oven at 80°C for 1 hour to obtain superhydrophobic wood.

[0063] Example 2

[0064] The tangential section of the wood was polished with sandpaper and washed with 75% ethanol and pure water. The treated wood was then soaked in a 0.1wt% NaOH solution for 2 h, and the residual NaOH on the wood surface was washed with deionized water. The wood was then dried in a 103°C oven for 6 h before use. 0.08g of HAP was added to 40g of ethyl acetate, followed by 0.8g of polydimethylsiloxane prepolymer and 0.08g of curing agent. The mixture was ultrasonically dispersed for 30 min to prepare a composite suspension. The prepared composite suspension was then heated to 1 g / cm 2 The amount of the solvent was sprayed on the polished surface of the wood at a distance of 30 to 50 cm from the wood, and then dried in an oven at 80°C for 1 hour to obtain superhydrophobic wood.

[0065] Example 3

[0066] The tangential section of the wood was polished with sandpaper and washed with 75% ethanol and pure water. The treated wood was then soaked in a 1 wt% NaOH solution for 2 h, and the residual NaOH on the wood surface was washed with deionized water. The wood was then dried in a 103°C oven for 6 h before use. 0.08 g of HAP was added to 40 g of ethyl acetate, followed by 0.8 g of polydimethylsiloxane prepolymer and 0.08 g of curing agent. The mixture was ultrasonically dispersed for 30 min to prepare a composite suspension. The prepared composite suspension was then heated to 1 g / cm 2 The amount of the solvent was sprayed on the polished surface of the wood at a distance of 30 to 50 cm from the wood, and then dried in an oven at 80°C for 1 hour to obtain superhydrophobic wood.

[0067] Example 4

[0068] The tangential section of the wood was polished with sandpaper and washed with 75% ethanol and pure water. The treated wood was then soaked in a 0.5 wt% NaOH solution for 2 h, and the residual NaOH on the wood surface was washed with deionized water. The wood was then dried in a 103°C oven for 6 h before use. 0.08 g of HAP was added to 48 g of ethyl acetate, followed by 0.8 g of polydimethylsiloxane prepolymer and 0.08 g of curing agent. The mixture was ultrasonically dispersed for 30 min to prepare a composite suspension. The prepared composite suspension was then heated to 1.2 g / cm 2 The amount of the solvent was sprayed on the polished surface of the wood at a distance of 30 to 50 cm from the wood, and then dried in an oven at 80°C for 1 hour to obtain superhydrophobic wood.

[0069] Example 5

[0070] The tangential section of the wood was polished with sandpaper and washed with 75% ethanol and pure water. The treated wood was then soaked in a 0.5 wt% NaOH solution for 1 hour and then taken out. The residual NaOH on the wood surface was washed with deionized water and then dried at room temperature (25°C) for 24 hours before use. 0.08 g of HAP was added to 32 g of ethyl acetate, followed by 0.8 g of polydimethylsiloxane prepolymer and 0.08 g of curing agent. The mixture was ultrasonically dispersed for 30 minutes to prepare a composite suspension. The prepared composite suspension was then heated to 0.8 g / cm 2 The amount of the hydrophobic agent was sprayed on the polished surface of the wood at a distance of 30 to 50 cm from the wood, and the wood was placed at room temperature (25°C) for 12 hours to obtain superhydrophobic wood.

[0071] Comparative Examples 1 to 3

[0072] The technical solutions of Comparative Examples 1 to 3 are similar to those of Example 1, except that Comparative Example 1 (WH-WE-W) is not alkali-treated and does not contain HAP, Comparative Example 2 (WH-EW) is alkali-treated and does not contain HAP, and Comparative Example 3 (H-WE-W) is not alkali-treated and contains HAP.

[0073] Comparative Examples 4-5

[0074] The technical solutions of Comparative Examples 4 to 5 are similar to those of Example 1, except that the concentrations of the NaOH solutions are 3 wt % and 5 wt %, respectively.

[0075] Comparative Examples 6-7

[0076] The technical solutions of Comparative Examples 6 to 7 are similar to those of Example 1, except that the alkali treatment time is 0.5 h and 4 h, respectively.

[0077] Comparative Examples 8-9

[0078] The technical solutions of Comparative Examples 8 to 9 are similar to those of Example 1, except that HAP is replaced by SiO2 and TiO2, respectively.

[0079] Detection method

[0080] (1) Extreme environment testing

[0081] The superhydrophobic wood of Example 1 was tape stripped 30 times (using 3M tape to peel the coating surface), subjected to 10L water shock (the sample was fixed on a slope with an inclination angle of 45°, and then the water was released at a distance of 30 cm from the wood sample), immersed in a strong acid and strong base solution for 12 hours (the sample surface coating was immersed in a strong acid and strong base solution), UV irradiation for 24 hours (the sample was placed 10 cm away from the UV lamp for irradiation), freeze-thaw cycles 5 times (the coating surface was repeatedly frozen and thawed), and exposed outdoors for 60 days. The water contact angle was measured.

[0082] (2) Coating self-repair test

[0083] The superhydrophobic wood of Example 1 was subjected to 7 wear-repair cycles (the sample coating was placed downward on 1500CW sandpaper, and a 50g weight was placed on the wood. The wood was pushed to move on the sandpaper surface, moving vertically 5cm and then horizontally 5cm, which was recorded as one wear cycle; the worn sample was placed in an oven at 100°C and taken out after 1h, which was recorded as one wear-repair cycle), and then the water contact angle was measured.

[0084] (3) Cross-section hydrophobicity test

[0085] The tangential section of the wood was polished with sandpaper and washed with 75% ethanol and pure water. 0.1 g, 0.08 g, 0.53 g, and 0.04 g of HAP were added to 40 g of ethyl acetate, followed by 0.8 g of polydimethylsiloxane prepolymer and 0.08 g of curing agent. The suspension was ultrasonically dispersed for 30 min to prepare a composite suspension. The composite suspension was then heated to 1 g / cm 2 The amount of the solvent was sprayed on the polished surface of the wood at a distance of 30 to 50 cm from the wood, and then dried in an oven at 80°C for 1 hour to obtain superhydrophobic wood.

[0086] Analysis

[0087] Depend on Figure 1 It can be seen that the hydroxyapatite nanospheres are spherical with a diameter of about 10 to 30 nm.

[0088] Figure 2 This is a water contact angle test diagram of the wood surface coating in Example 1, and its water contact angle is about 153.3°.

[0089] like Figure 3 As shown, Example 1 was treated with alkali and HAP was added at the same time, and the contact angle of the HEW sample was as high as 153.3°, with the smallest rolling angle (4.3°), showing the best hydrophobic performance. Comparative Example 1 was not treated with alkali and no HAP was added. The water contact angle on the surface of the WH-WE-W sample was low (145.3°) and the rolling angle was high, indicating that its hydrophobic performance was poor. Comparative Example 2 was treated with alkali but no HAP was added. Although the water contact angle on the surface of the WH-EW sample was slightly improved (146.8°), the rolling angle was still high. Comparative Example 3 was not treated with alkali but HAP was added. It shows that although the H-WE-W sample with only HAP added improved the water droplet rolling performance, the water contact angle was still lower than that of the HEW sample in Example 1. The above results show that the synergistic effect of alkali treatment and HAP can significantly increase the roughness of the wood surface, increase the surface active sites, and thus greatly enhance its hydrophobicity.

[0090] like Figure 4As shown, the surface of natural wood is relatively smooth and the color distribution is relatively uniform, indicating that the surface microstructure is less and the average roughness is lower ( Figure 4 a). The wood surface after alkali treatment in Example 6 showed more red areas, representing an increase in surface height differences ( Figure 4 b) Because the alkali treatment partially corrodes the wood surface, creating a rougher microstructure, the wood surface provides more active sites for the hydrophobic coating to adhere, enhancing the coating's stability and hydrophobic effect. The average surface roughness Ra of natural wood is 3.9 μm, while the surface roughness of the wood in Example 3 is significantly increased to 8.5 μm.

[0091] like Figure 5 As shown in Figure a, when the NaOH concentration is 0.1wt%, 0.5wt%, and 1wt% (Examples 1 to 3), the water contact angle is greater than 150°, reaching the super-hydrophobic condition (the test results of Examples 4 to 5 are all greater than 150°). However, when the NaOH concentration is further increased to 3wt% and 5wt%, the contact angle decreases instead. This is because the excessively high concentration of alkaline solution causes excessive corrosion on the wood surface, destroys the appropriate microscopic roughness structure, reduces the active sites, and thus reduces the hydrophobicity. Figure 5 As shown in Figure 2, as the alkali treatment soaking time is extended, the water contact angle gradually increases. However, when the soaking time exceeds 2 hours (such as 4 hours in Comparative Example 7), the water contact angle of the wood prepared is 145.5°. When the soaking time of Comparative Example 6 is 0.5 hours, the wood surface roughness is insufficient, and the water contact angle of the wood prepared is 147.3°. When the NaOH concentration is too high and the soaking time is not within the appropriate range, the water contact angle of the resulting wood is less than 150°, which does not meet the super-hydrophobic standard.

[0092] like Figure 6As shown, the HAP-based coating in Example 1 achieved a water contact angle of 153.3°, while samples containing silicon dioxide (Comparative Example 8) and titanium dioxide (Comparative Example 9) all achieved water contact angles less than 150°, failing to achieve superhydrophobicity. Superhydrophobicity relies on the micro-nanostructure of the material surface to increase the contact angle between water droplets and the surface. HAP can form a more uniform and rougher microstructure on the wood surface, making it nearly impossible for water droplets to penetrate the microscopic gaps, resulting in a high contact angle. SiO2 and TiO2 inherently have high hydrophilicity. The surface of silicon oxide has a large number of silanol (Si-OH) groups, which can form hydrogen bonds with water molecules, increasing the interaction between water and the material surface and thus limiting the contact angle of water droplets. TiO2 also has hydrophilic properties at room temperature, and this hydrophilicity is enhanced by surface oxidation reactions, especially when exposed to light. Therefore, even after these materials are hydrophobically modified, their inherent hydrophilic properties are difficult to completely eliminate, affecting the ultimate hydrophobic effect. When PDMS is used as the modifier, the numerous active sites on the HAP particle surface enable better bonding with PDMS, forming a stable hydrophobic coating. However, for SiO2 and TiO2, the chemical reaction during bonding with PDMS is less effective than with HAP, resulting in reduced stability and hydrophobicity of the hydrophobic layer, ultimately leading to a smaller contact angle and suboptimal hydrophobic performance. Furthermore, due to surface energy and interparticle interactions, SiO2 and TiO2 nanoparticles are prone to agglomeration or uneven distribution, reducing hydrophobicity.

[0093] according to Figure 7 a~f, the preparation method of the present invention not only significantly improves the hydrophobic properties of wood, but also in the face of various harsh environments such as mechanical stripping, water shock, chemical corrosion, ultraviolet light, freeze-thaw cycles and long-term outdoor exposure, the water contact angle has almost no change and remains above 150°. It shows that the super-hydrophobic coating on the surface of wood has strong adhesion and peeling resistance, is suitable for complex outdoor environments such as heavy rain, long-term sun exposure, alternating hot and cold, and maintains stable performance. After 60 days of exposure to the outdoors, the water contact angle was about 152.5° and the rolling angle was 6.1°. In addition, according to Figure 7 g~h, after alkali etching, the bending strength and compressive strength of the wood did not decrease significantly, which verified that this method would not destroy the mechanical properties of the wood itself and ensure its structural safety in practical applications.

[0094] according to Figure 8a~e, the changes in water contact angle after two repair cycles at 40℃, 60℃, 80℃, 100℃ and 120℃. At lower temperatures (such as 40℃ and 60℃), the water contact angle changes greatly and the repair effect is unstable. At 100℃, the contact angle always remains at a high level (all over 150°), and the contact angle fluctuates less after repair, proving that its repair effect is the best. At 120℃, although the contact angle can be restored in a short time, Figure 8 As shown in Figure g, the wood underwent obvious deformation at this temperature, indicating that the high temperature damaged the wood itself and it was difficult to maintain the mechanical properties of the material. Figure 8 Figure f shows the repair rate at various temperatures as a function of the number of repair cycles. It can be seen that the repair rate at 80°C and 100°C remains high, even exceeding 90% after multiple repair cycles. However, the repair rate decreases significantly at lower temperatures (e.g., 40°C) and higher temperatures (e.g., 120°C). Figure 8 i shows the change in contact angle after 7 repairs at 100°C. Although the water contact angle decreased slightly, it still maintained a high level, indicating good durability. At 100°C, after 7 wear-repair cycles, the water contact angle of the wood surface can still be restored to 142°, with a repair rate of 92.4%, showing extremely high self-repair performance ( Figure 8 h). Figure 8 Figure j shows the change in contact angle after wear and repair. At 100°C, the water droplet contact angle dropped below 90° after the coating was worn, but the contact angle recovered rapidly after repair, approaching the original superhydrophobic level, indicating that the superhydrophobic coating has good self-healing ability.

[0095] according to Figure 9 When the composite suspension of the present invention was sprayed on a cross-section, the water contact angle on the wood surface was greater than 150° when the mass ratio of HAP to PDMS in the composite suspension was 1:8-20. When the mass ratio of HAP to PDMS in the composite suspension was 1:10, the hydrophobicity on the wood cross-section was the highest, with a water contact angle of 156.1°.

[0096] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing super-hydrophobic wood, characterized in that, The following steps are involved: S1: alkaline etching treatment of wood; S2: spraying a composite suspension containing nano-hydroxyapatite, polydimethylsiloxane, ethyl acetate and a curing agent onto the wood surface, and obtaining superhydrophobic wood after curing; During the alkaline etching treatment in S1, the wood is immersed in an alkaline solution with a concentration of 0.1-1 wt%; During the alkaline etching treatment described in S1, the wood is immersed in an alkaline solution for a soaking time of 0.5 to 4 hours.

2. The method for preparing super-hydrophobic wood according to claim 1, wherein The mass ratio of ethyl acetate to nano-hydroxyapatite is 400~600:

1.

3. The method for preparing super-hydrophobic wood according to claim 1, wherein In the composite suspension described in S2, the mass ratio of nano-hydroxyapatite to polydimethylsiloxane is 1:8~20.

4. The method for preparing super-hydrophobic wood according to claim 1, wherein The amount of the composite suspension in S2 added to the wood surface is 0.8~1.2 g / cm 2 .

5. The method for preparing super-hydrophobic wood according to claim 1, wherein The wood surface described in S2 includes a transverse section, a tangential section, and a radial section.

6. A superhydrophobic wood, characterized in that The compound is prepared by the preparation method according to any one of claims 1 to 5.

7. The super-hydrophobic wood according to claim 6, characterized in that: After being damaged, the superhydrophobic coating can be restored at a temperature above 80°C and below 120°C.

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