Tie Lu, Zhao Siyang, Guo Zhiguang, Li Jing
State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China.
Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei University, Wuhan 430062, P. R. China.
Langmuir. 2020 Apr 7;36(13):3300-3307. doi: 10.1021/acs.langmuir.0c00154. Epub 2020 Mar 27.
Switching between superhydrophobicity/underwater superoleophilicity and superhydrophilicity/underwater superoleophobicity has been widely designed. Recently, superwettability is subdivided into multiple extreme wetting states for oil, water, and air as wetting and medium phases. However, fine switching among the multiple superwettability is rare. Here, a pH-responsive case is presented to demonstrate the fine switching between underwater superoleophilicity and underwater superoleophobicity while maintaining superhydrophobicity. The surface chemistry of silver-roughened copper coatings is elaborately manipulated by water-repellent perfluoroalkyl and alkyl chains and the smart terminal carboxyl group. By adjusting the pH value of water, the completely opposite extreme wetting states for oil in water are precisely controlled. Simultaneously, the extreme repellence for water in the air can be kept owing to the fairly low surface energy of the perfluoroalkyl chain. This discovery accelerates the subdivision of superwettability and the achievement of unusual superwetting switching.
超疏水性/水下超亲油性与超亲水性/水下超疏油性之间的切换已被广泛设计。最近，超润湿性被细分为油、水和空气作为润湿相和介质相的多种极端润湿状态。然而，在多种超润湿性之间进行精细切换的情况很少见。在此，提出了一个pH响应案例，以展示在保持超疏水性的同时，水下超亲油性和水下超疏油性之间的精细切换。通过疏水性全氟烷基和烷基链以及智能末端羧基对银粗糙化铜涂层的表面化学进行精心调控。通过调节水的pH值，可以精确控制水中油的完全相反的极端润湿状态。同时，由于全氟烷基链的表面能相当低，在空气中对水的极端排斥性得以保持。这一发现加速了超润湿性的细分以及实现异常的超润湿切换。
