Polydimethylsiloxane-Based Superhydrophobic Surfaces on Steel Substrate: Fabrication, Reversibly Extreme Wettability and Oil-Water Separation

Xiaojing Su, Hongqiang Li*, Xuejun Lai, Lin Zhang, Tao Liang, Yuchun Feng, and Xingrong Zeng*

Abstract: Functional surfaces for reversibly switchable wettability and oil-water separation have attracted much interest with pushing forward an immense influence on fundamental research and industrial application in recent years. This article proposed a facile method to fabricate superhydrophobic surfaces on steel substrates via electroless replacement deposition of copper sulfate (CuSO₄) and UV curing of vinyl terminated polydimethylsiloxane (PDMS). PDMS-based superhydrophobic surfaces exhibited water contact angle (WCA) nearly to 160^o and water sliding angle (WSA) lower than 5^o, preserving outstanding chemical stability which maintained superhydrophobicity immersing in different aqueous solutions with pH values from 1 to 13 for 12 h. Interestingly, the superhydrophobic surface could dramatically switch to superhydrophilic state under UV irradiation, and then gradually recover to highly hydrophobic state with WCA at 140^o after dark storage. The underlying mechanism was also investigated by scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Additionally, the PDMS-based steel mesh possessed high separation efficiency and excellent reusability in oil-water separation. Our studies provide a simple, fast and economical fabrication method for wettability-transformable superhydrophobic surfaces and have the potential applications in microfluidics, biomedical field and oil spill clean-up.

论文链接：http://dx.doi.org/10.1021/acsami.6b13901