| DU Wen-qian,WANG De-hui,YU Hua-li,LI Luo-hui-zi,LUO Jing,DENG Xu.Weather Resistance and Failure Mechanism of Superhydrophobic Copper Surface Modified by Mercaptans[J],52(11):326-334 |
| Weather Resistance and Failure Mechanism of Superhydrophobic Copper Surface Modified by Mercaptans |
| Received:November 15, 2022 Revised:February 08, 2023 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2023.11.027 |
| KeyWord:superhydrophobic copper surface chemical etching method mercaptan modification environmental weather resistance superhydrophobic failure failure mechanism |
| Author | Institution |
| DU Wen-qian |
Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu , China |
| WANG De-hui |
Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu , China;Key Laboratory of Icing and Anti/De-icing, China Aerodynamics Research and Development Center, Sichuan Mianyang , China |
| YU Hua-li |
Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu , China |
| LI Luo-hui-zi |
Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu , China |
| LUO Jing |
Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu , China |
| DENG Xu |
Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu , China |
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| Abstract: |
| The superhydrophobic copper surface has a very broad application prospect in the fields of self-cleaning, anti-frost, anti-corrosion, reduction of resistance and residue of fluid in copper pipes, etc. However, the weather resistance of the superhydrophobic copper surface in the real application environment is not clear, and there is still short of systematic research. Therefore, the work aims to explore the failure factors of mercaptan modified superhydrophobic copper surface in outdoor environment and the mechanism of superhydrophobic failure. The nanostructure was constructed on the copper surface by chemical etching, and then the surface was modified with 1-dodecanethiol to obtain a superhydrophobic copper surface (SCS). The SCS was placed outdoors to study its weather resistance. The mechanism of failure was explored by four kinds of experiments simulating outdoor conditions. Simulation experiments included combinatorial cycle experiment (cyclic conditions including UV radiation, rain and condensation), UV radiation experiment, water environment experiment and temperature experiment ("high temperature" in this work referred to the high temperature in the outdoor environment). The mechanism of superhydrophobicity failure of SCS was verified by the environmental weather resistance of hydrophobic copper surface (HCS) without rough microstructure. Scanning electron microscope (SEM), contact angle measurement and X-ray photoelectron spectrometer (XPS) were used to characterize the morphology, wettability and chemical composition of SCS, respectively. After 10 days of outdoor experiments, the water contact angle of SCS was reduced from the initial 158.5° to 131.1°. According to the SEM diagram and Energy Dispersive Spectrometer (EDS) analysis, impurities containing metal/non-metal inorganic substances and organic matter were absorbed on the surface. The experimental results showed that the superhydrophobic performance of SCS failed and the self-cleaning performance was also lost. The water contact angle of SCS decreased to 130.3°, 124.5° and 131.7° after 2 combinatorial cycle experiments (12 hours of each cycle), 20 days of UV radiation experiment, and 30 days of water environment experiment respectively, indicating that SCS lost its superhydrophobic property. After 20 days of high temperature experiment, SCS still maintained superhydrophobic property, but the superhydrophobic property began to fail after 40 days of high temperature experiment. XPS spectrum indicated that sulfur element was no longer present on SCS after the failure of superhydrophobic properties, i.e. 1-dodecanethiol was removed from SCS. The shedding of mercaptan molecules on the SCS was the root cause of superhydrophobic failure. UV radiation, water and high temperature were the main factors leading to the failure of superhydrophobicity of SCS. The superhydrophobic property of SCS was destroyed faster by UV radiation or water than by high temperature. Compared with the effect of a single factor (UV radiation, water or high temperature), the synergistic effect of the three accelerated the shedding of mercaptan molecules from SCS, thereby accelerating the rate of superhydrophobic failure. By studying the weather resistance and failure mechanism of HCS, it is found that the wettability change trend of HCS is consistent with that of SCS, and the hydrophobicity failure of HCS without rough microstructure is also caused by the shedding of mercaptan molecules on the surface. The results verify that the mercaptan molecule detachment from the surface results in the superhydrophobic failure of SCS. |
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