Fabrication of superhydrophobic surfaces for applications in total internal reflection effects

Superhydrophobic surfaces have attracted significant attention in the applied science community. This paper presents three different methods for fabricating superhydrophobic surfaces, which can be applied in liquid light guides with the total internal reflection effect playing a central role. The selective bi-polymer etching only produces a hydrophobic porous poly(methyl methacrylate) surface but is simple and versatile for use on an arbitrary surface. In metal-assisted chemical etching, wet etching of a silver layer on a silicon sample creates porous silicon with superhydrophobicity, characterized by a water contact angle of 160°. The metal-assisted chemical etching method modified with the presence of polystyrene nanoparticles further improved the water contact angle to 164° by creating a nanopillar silicon structure. The metal-assisted chemical etching methods are more complicated but can produce superhydrophobic surfaces with very high water contact angles. These results show that superhydrophobic surfaces fabricated by methods in this study can be used for total internal reflection effect at the interface between water with huge potential applications in liquid light guides.