金属基体上超疏水表面的制备及其机械耐久性的研究进展

在金属基体上构建超疏水表面可有效解决金属材料在使用过程中不耐腐蚀、容易覆冰等问题,同时赋予其自清洁、油水分离、润滑减阻等特殊功能,具有极高的应用价值和市场前景。但目前普遍存在的规模化生产困难及机械耐久性差的两大问题严重限制了其实际应用。归纳了在金属基体上制备超疏水表面的基本方法,对化学刻蚀法、阳极氧化法、电化学沉积法、水热法、喷涂法等5种典型方法进行了重点综述,讨论了其优劣势,并结合最新研究进展,提出低表面能改性剂的绿色环保化和一步法制备超疏水表面是未来的发展趋势。针对超疏水表面机械耐久性的问题,分析了机械磨损导致超疏水材料失效的原因,总结了机械稳定性的测试手段和评价机制,然后立足于机械稳定性和化学稳定性两个关键因素,提出提高金属基体上超疏水表面的机械耐久性,延长服役寿命的4种基本方法:1)精细设计微纳米多级复合结构;2)引入粘结层以加固表面微观结构;3)不使用低表面能物质,仅靠粗糙结构实现超疏水;4)构建自修复表面。最后对该领域未来的研究重点和发展趋势进行了展望。

Research Progress of the Preparation and Mechanical Durability of Superhydrophobic Surfaces on Metal Substrates

The fabrication of superhydrophobic surfaces on metal substrates is an effective way to solve the problems of easy corrosion and easy ice-coating of metal materials during the course of use, besides, it can also endow surfaces with special functions such as self-cleaning, oil-water separation, lubrication and drag reduction etc, which definitely has considerable practical application value and far-reaching prospect. However, its practical application has been severely hindered currently by two widespread challenges which are difficult large-scale production and poor mechanical durability. In this review, the basic methods of preparing superhydrophobic surfaces were introduced, and five typical methods were summarized, such as chemical etching, anodizing, electrochemical deposition, hydrothermal process and spraying method and their advantages and disadvantages were discussed. In combination with the latest research progress, two promising research trends were proposed, which were to explore and use more economical and eco-friendly low surface energy substance as hydrophobic modifying agents and to combine the construction of micro- and nanostructed roughness and hydrophobic modification as one-step preparation of superhydrophobic surface. With respect to the mechanical durability of superhydrophobic surface, the causes for the failure of superhydrophobic materials caused by mechanical abrasion were analyzed and the testing methods and evaluation mechanism of the mechanical stability were summarized. Then, based on two key factors like mechanical stability and chemical stability, the following points were proposed: 1) elaborately design micro-nano multi-stage composite structure; 2) introduce bonding layer to reinforce surface microstructure; 3) achieve superhydrophobicity without using low surface energy modifier, but only with coarse structures; 4) construct self-repairing surface to improve the mechanical durability of superhydrophobic surfaces on the metal substrates and prolong the service life. Finally, the urgently demanded research focus and promising development trend of this field are prospected.