Fabrication of coral-like superhydrophobic coating on filter paper for water–oil separation

The physics related to superhydrophobic surfaces has been investigated with attention of its potential applications in a variety of industrial and scientific fields. In the present study, a coralloid superhydrophobic coating with numerous nanometer-scale embossments has been fabricated on the filter paper surface by a simple, facile and inexpensive route. The observations show that the wettability of paper sample has been transformed from superhydrophilicity to superhydrophobicity with the WCA of 156°, and had no significant change under ambient condition or in the water, oil and corrosive liquids, displaying an outstanding superhydrophobic stability. Importantly, the coated paper sample possesses not only superhydrophobicity but also superoleophobicity, and presents an excellent property in water–oil separation, which offers an opportunity to extend the range of practical applications for filter paper.