Method for constructing composite super-hydrophobic coating through dual bonding

Abstract

The invention relates to a method for constructing a composite super-hydrophobic coating through double bonding. The preparation method comprises the following steps: taking a clean copper sheet which is not pretreated as a substrate, dipping the copper sheet in a suspension consisting of nanoparticles and sulfydryl-containing siloxane ethanol, taking out, washing, drying, dipping in a perfluoromercaptan ethanol solution, taking out, washing, and drying to obtain the copper-based super-hydrophobic surface coating. The coating prepared by the method has excellent super-hydrophobicity, icing resistance and stability. Different from an existing conventional preparation method, the method has the advantages that pretreatment operation such as abrasive paper polishing, strong acid etching or anodic oxidation does not need to be carried out on a copper sheet, and micro-nano roughening and low-surface-energy self-assembly can be completed on the copper surface only through two-step normal-temperature dipping. The method is simple in preparation process, mild in condition, free of expensive equipment, thin in coating thickness and small in influence on electric conduction and heat conduction of the copper substrate, intrinsic performance of copper can be reserved, the electric conduction / heat conduction characteristic of the copper substrate is considered, and the method has wide application value and prospects.

Description

Technical Field

[0001] This invention belongs to the field of metal surface functionalization technology, and relates to superhydrophobic coating preparation technology, specifically a method for preparing a superhydrophobic copper-based surface coating. Background Technology

[0002] Constructing hydrophobic surfaces can endow substrates with multiple functions such as anti-icing, corrosion resistance, self-cleaning, and anti-fouling. In aviation, cold chain, and power industries, it can inhibit frost nucleation and ice accumulation, ensuring operational safety under extreme climates. In shipbuilding, marine engineering, and transportation, the hydrophobic barrier isolates water molecules and corrosive ions, slowing down metal corrosion and enabling maintenance-free, long-term equipment use. Furthermore, the increased droplet contact angle and reduced roll-off angle allow dust and bacteria to be shed as water droplets roll off, giving the substrate self-cleaning and anti-fouling properties. With these green, efficient, and economical advantages, hydrophobic surface technology has become an indispensable key functional interface in building energy conservation, marine engineering, energy equipment, and electronic devices.

[0003] Existing technologies often employ methods such as hydrofluoric acid / hydrogen peroxide chemical etching, anodic oxidation, laser texturing, or electrochemical deposition to first construct a rough structure, and then spray low surface energy materials to prepare a superhydrophobic coating. Building upon this foundation, it is meaningful to simplify the process and further develop a preparation process that is energy-efficient, environmentally friendly, operates under mild conditions, and exhibits superior hydrophobic durability, anti-icing properties, and mechanical stability.

[0004] This invention proposes a method for constructing a superhydrophobic surface coating by utilizing the combined action of nanoparticles, mercapto-containing siloxanes, and perfluorothiols to form a micro-nano composite rough structure through double bonding, thereby improving the superhydrophobicity and stability of the coating. Summary of the Invention

[0005] The purpose of this invention is to provide a simple and easy method for constructing superhydrophobic surface coatings, which achieves micro-nano composite roughening and low surface energy self-assembly on the material surface, thereby obtaining a superhydrophobic coating with high contact angle, low roll-off angle, anti-icing, wear resistance and good electrical / thermal conductivity.

[0006] To achieve the above objectives, the present invention employs the following technical methods:

[0007] Using a clean copper sheet as a substrate, nanoparticles and mercapto-containing siloxanes are ultrasonically dispersed in anhydrous ethanol to obtain a suspension. The copper sheet is immersed in the suspension for a period of time, then removed, rinsed with deionized water, and dried at 60°C, forming a micro-nano composite rough structure on the copper surface. Perfluorothiol is dissolved in anhydrous ethanol to obtain a perfluorothiol ethanol impregnation solution. The copper sheet sample with the micro-nano composite rough structure is placed in the perfluorothiol ethanol impregnation solution for a period of time, then removed, rinsed with anhydrous ethanol, and dried at 60°C to obtain a composite superhydrophobic surface coating. The above preparation method has the following main characteristics:

[0008] The nanoparticles used are at least one of TiO2, SiO2, ZnO, and Fe3O4.

[0009] Preferably, the average particle size of the nanoparticles is 10–300 nm, and the content of the nanoparticles in the ethanol suspension is 0.01–6.00 wt%.

[0010] The mercapto-containing siloxane is at least one of 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropyldimethylmethoxysilane.

[0011] Preferably, the molar amount of the mercapto-containing siloxane is 1–10 times that of TiO2.

[0012] Preferably, the immersion time in the suspension is 10–60 min.

[0013] The aforementioned micro-nano composite rough structure is constructed by using a thiol-containing siloxane as a bridge, through the binding of the siloxane with the hydroxyl groups on the surface of the nanoparticles, and the binding of the thiol groups with the copper substrate.

[0014] The perfluorothiol is at least one of 2-(perfluorobutyl)ethanethiol, 1H,1H,2H,2H-perfluorobutanethiol, 1H,1H,2H,2H-perfluorohexanethiol, 1H,1H,2H,2H-perfluorooctanethiol, 1H,1H,2H,2H-perfluorodecanethiol, 1H,1H,2H,2H-perfluorododecanethiol, and 1H,1H,2H,2H-perfluorotetradecanethiol.

[0015] The perfluorothiol ethanol solution contains 0.1–3.0 wt% perfluorothiol, and the copper sheet is immersed in the perfluorothiol immersion solution for 10 min–4 h.

[0016] The order of the two impregnation steps in the preparation method can be reversed.

[0017] Unlike other methods for preparing hydrophobic coatings, the method provided in this invention is unique. It utilizes the combined action of nanoparticles, mercapto-containing siloxanes, and perfluorothiols. Through the dual bonding between the mercapto groups in the mercapto-containing siloxanes and perfluorothiols and copper, a composite micro-nano rough structure is self-assembled on the copper-based surface to form a superhydrophobic surface coating with excellent superhydrophobic, anti-icing, and wear-resistant properties.

[0018] The superhydrophobic coating construction process of this invention is completed entirely at room temperature and pressure, requiring no strong acids, strong oxidants, or expensive vacuum / laser equipment. The ethanol solution used as the dispersion solvent can be directly distilled and recovered, making it environmentally friendly. The coating is thin, having minimal impact on the electrical and thermal conductivity of the copper substrate, thus preserving the intrinsic properties of copper. The superhydrophobic coating prepared by this invention has broad practical application value and promising prospects. Attached Figure Description

[0019] Figure 1 This is a contact angle diagram of the coating constructed according to the present invention;

[0020] Figure 2 This is a comparison of the freezing time of the coating constructed in this invention; Detailed Implementation

[0021] The present invention will be further described below with reference to embodiments, but the present invention is not limited to the following embodiments. All other embodiments obtained by other persons skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0022] Example 1

[0023] TiO2 nanoparticles (0.0039 g, 20 nm) were added to an anhydrous ethanol solution (50 mL) containing 120 μL of 3-mercaptopropyltrimethoxysilane (KH590) and sonicated for 30 min to form a suspension. A clean copper sheet was immersed in the suspension and kept for 60 min. The copper sheet was then removed, rinsed with deionized water, and dried at 60 °C for 30 min. 24 μL of 1H,1H,2H,2H-perfluorodecanethiol (PFDT) was dissolved in 50 mL of anhydrous ethanol to form a PFDT ethanol impregnation solution. The copper sheet treated as described above was placed in the PFDT ethanol impregnation solution and immersed for 4 h. After immersion, the copper sheet was rinsed with anhydrous ethanol and dried at 60 °C for 30 min to obtain a copper-based superhydrophobic surface coating.

[0024] Example 2

[0025] TiO2 nanoparticles (2.3670 g, 20 nm) were added to an anhydrous ethanol solution (50 mL) containing 3-mercaptopropyltrimethoxysilane (7.2 mL, KH590) and sonicated for 30 min to form a suspension. A clean copper sheet was immersed in the suspension and kept for 10 min. The copper sheet was then removed, rinsed with deionized water, and dried at 60 °C for 30 min. 705 μL of 1H,1H,2H,2H-perfluorodecanethiol (PFDT) was dissolved in 50 mL of anhydrous ethanol to form a PFDT ethanol impregnation solution. The copper sheet treated as described above was placed in the PFDT ethanol impregnation solution and immersed for 10 min. After immersion, the copper sheet was rinsed with anhydrous ethanol and dried at 60 °C for 30 min to obtain a copper-based superhydrophobic surface coating.

[0026] Example 3

[0027] ZnO nanoparticles (0.0039 g, 10 nm) were added to an anhydrous ethanol solution (50 mL) containing 3-mercaptopropylmethyldimethoxysilane (88 μL, KH8O2). After sonication for 30 min, a suspension was formed. A clean copper sheet was immersed in the suspension and kept for 60 min. The copper sheet was then removed, rinsed with deionized water, and dried at 60 °C for 30 min. 26 μL of 1H,1H,2H,2H-perfluorohexanethiol (PFHT) was dissolved in 50 mL of anhydrous ethanol to form a PFHT ethanol impregnation solution. The copper sheet treated as described above was placed in the PFHT ethanol impregnation solution and immersed for 4 h. After immersion, the copper sheet was rinsed with anhydrous ethanol and dried at 60 °C for 30 min to obtain a copper-based superhydrophobic surface coating.

[0028] Example 4

[0029] SiO2 nanoparticles (2.3670 g, 300 nm) were added to an anhydrous ethanol solution (50 mL) containing 3-mercaptopropyltriethoxysilane (7.2 mL, KH580) and sonicated for 30 min to form a suspension. A clean copper sheet was immersed in the suspension and kept for 10 min. The copper sheet was then removed, rinsed with deionized water, and dried at 60 °C for 30 min. 731 μL of 1H,1H,2H,2H-perfluorooctyl mercaptan (PFOT) was dissolved in 50 mL of anhydrous ethanol to form a PFOT ethanol impregnation solution. The copper sheet treated as described above was placed in the PFOT ethanol impregnation solution and immersed for 10 min. After immersion, the copper sheet was rinsed with anhydrous ethanol and dried at 60 °C for 30 min to obtain a copper-based superhydrophobic surface coating.

[0030] Example 5

[0031] TiO2 nanoparticles (0.0138 g, 30 nm) were added to an anhydrous ethanol solution (50 mL) containing 3-mercaptopropyltrimethoxysilane (32 μL, KH590) and sonicated for 30 min to form a suspension. A clean copper sheet was immersed in the suspension and kept for 40 min. The copper sheet was then removed, rinsed with deionized water, and dried at 60 °C for 30 min. 350 μL of 1H,1H,2H,2H-perfluorodecanethiol (PFDT) was dissolved in 50 mL of anhydrous ethanol to form a PFDT ethanol impregnation solution. The copper sheet treated as described above was placed in the PFDT ethanol impregnation solution and immersed for 3 h. After immersion, the copper sheet was rinsed with anhydrous ethanol and dried at 60 °C for 30 min to obtain a copper-based superhydrophobic surface coating.

[0032] Example 6

[0033] The freezing time of the coating surface was tested using a thermoelectric cooling plate. The temperature of the thermoelectric cooling plate was set to -1.0℃, and the ambient humidity was controlled at 35±3%. After the temperature stabilized, a copper sheet with 20μL of water droplets was placed on the surface of the thermoelectric cooling plate, and the freezing process and freezing time of the water droplets were recorded with a camera.

[0034] Comparative Example 1

[0035] Dissolve 325 μL of 1H,1H,2H,2H-perfluorodecanethiol (PFDT) in 50 mL of anhydrous ethanol to form a PFDT ethanol impregnation solution. Place a clean copper sheet into the PFDT ethanol impregnation solution and immerse it for 4 hours. Then remove the sheet, rinse it with anhydrous ethanol, and dry it at 60 °C for 30 minutes to obtain a copper-based surface coating.

[0036] Comparative Example 2

[0037] TiO2 nanoparticles (0.0552 g, 20 nm) were added to anhydrous ethanol solution (50 mL) and sonicated for 30 min to form a suspension. A clean copper sheet was immersed in the suspension and kept for 30 min. The copper sheet was then removed, rinsed with deionized water, and dried at 60 °C for 30 min. 325 μL of 1H,1H,2H,2H-perfluorodecanethiol (PFDT) was dissolved in 50 mL of anhydrous ethanol to form a PFDT ethanol impregnation solution. The copper sheet treated as above was placed in the PFDT ethanol impregnation solution and immersed for 4 h. After immersion, the copper sheet was rinsed with anhydrous ethanol and dried at 60 °C for 30 min to obtain a copper-based surface coating.

[0038] Comparative Example 3

[0039] Dissolve 129 μL of 3-mercaptopropyltrimethoxysilane (KH590) in 50 mL of anhydrous ethanol to form a KH590 ethanol impregnation solution. Immerse a clean copper sheet in the KH590 ethanol impregnation solution for 30 min, then remove it, rinse with anhydrous ethanol, and dry at 60 °C for 30 min. Dissolve 325 μL of 1H,1H,2H,2H-perfluorodecanethiol (PFDT) in 50 mL of anhydrous ethanol to form a PFDT ethanol impregnation solution. Immerse the copper sheet treated above in the PFDT ethanol impregnation solution for 4 h, then remove it, rinse with anhydrous ethanol, and dry at 60 °C for 30 min to obtain a copper-based surface coating.

[0040] Table 1. Measurement results of sample contact angle and freezing time

[0041] Contact angle Freezing time (-1.0℃ 35% RH) Uncoated copper sheet 65.65° 1min Comparative Example 1 120.30° 16min Comparative Example 2 130.55° 26min Comparative Example 3 137.45° 33min Example 5 169.30° 67min

Claims

1. A method for constructing a composite superhydrophobic coating through dual bonding, characterized in that, A micro-nano composite rough structure is constructed through double bonding to form a superhydrophobic surface coating. The steps include: using a clean copper sheet as a substrate, nanoparticles and mercapto-containing siloxanes are ultrasonically dispersed in anhydrous ethanol to obtain a suspension; the copper sheet is immersed in the suspension and removed after a period of time, rinsed with deionized water, and dried at 60°C to form a micro-nano composite rough structure on the copper surface; perfluorothiol is dissolved in anhydrous ethanol solvent to obtain a perfluorothiol ethanol impregnation solution; the copper sheet sample with the micro-nano composite rough structure is placed in the perfluorothiol ethanol impregnation solution and removed after a period of time, rinsed with anhydrous ethanol, and dried at 60°C to obtain a composite superhydrophobic surface coating.

2. The method for constructing a composite superhydrophobic coating by double bonding according to claim 1, characterized in that, The nanoparticles are at least one of TiO2, SiO2, ZnO, and Fe3O4, with an average particle size of 10–300 nm and a content of 0.01–6.00 wt% in the ethanol suspension.

3. The method for constructing a composite superhydrophobic coating by double bonding according to claim 1, characterized in that, The mercapto-containing siloxane is at least one of 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropyldimethylmethoxysilane.

4. The method for constructing a composite superhydrophobic coating by double bonding according to claim 1, characterized in that, The molar amount of the mercapto-containing siloxane is 1–10 times that of TiO2.

5. A method for constructing a composite superhydrophobic coating by double bonding according to claim 1, characterized in that, The immersion time in the suspension is 10–60 min.

6. A method for constructing a composite superhydrophobic coating by double bonding according to claim 1, characterized in that, The aforementioned micro-nano composite rough structure is constructed by using a thiol-containing siloxane as a bridge, through the binding of the siloxane with the hydroxyl groups on the surface of the nanoparticles, and the binding of the thiol groups with the copper substrate.

7. A method for constructing a composite superhydrophobic coating by double bonding according to claim 1, characterized in that, The perfluorothiol is at least one of 2-(perfluorobutyl)ethanethiol, 1H,1H,2H,2H-perfluorobutanethiol, 1H,1H,2H,2H-perfluorohexanethiol, 1H,1H,2H,2H-perfluorooctanethiol, 1H,1H,2H,2H-perfluorodecanethiol, 1H,1H,2H,2H-perfluorododecanethiol, and 1H,1H,2H,2H-perfluorotetradecanethiol.

8. A method for constructing a composite superhydrophobic coating by double bonding according to claim 1, characterized in that, The perfluorothiol ethanol solution contains 0.1–3.0 wt% perfluorothiol, and the copper sheet is immersed in the perfluorothiol ethanol solution for 10 min–4 h.

9. A method for constructing a composite superhydrophobic coating by double bonding according to claim 1, characterized in that, The order of the two impregnation steps in the preparation method can be reversed.

10. A method for constructing a composite superhydrophobic coating by double bonding according to claim 1, characterized in that, The superhydrophobic surface coating is a micro-nano rough structure constructed on a copper-based surface by nanoparticles, mercapto-containing siloxanes, and perfluorothiols. Through the dual bonding self-assembly of the mercapto-containing siloxanes and perfluorothiols with copper at two sites, excellent superhydrophobicity, anti-icing properties, wear resistance, and stability are achieved.

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