Transparent smart surface with pH-induced wettability transition between superhydrophobicity and underwater superoleophobicity

Smart surface with the switchable water/oil extreme wettability by external stimuli has great research and application value. In this paper, we present transparent smart surfaces with pH-responsive water wettability in air and oil wettability in water via grafting pH-responsive block copolymers on an inverse opal film. The resulting transparent surface not only shows superhydrophobicity in air but also displays the underwater superoleophobicity after treatment with acid. This transition in wettability is reversible and can be repeated multiple times through adjusting the pH value on the surface. Moreover, this smart surface sustains its superhydrophobicity and underwater superoleophobicity after being abraded with the sand or immersed into NaCl aqueous solutions for 7   days. This transparent surface may be useful for the development of swimsuits, microfluidic valves, automotive glass and solar cells.