Fabrication of the Superhydrophobic Surface Using SU-8 Photoresist with Black Silicon

A novel change method of surface wettability using both micro- and nano-sized geometrical shape is presented in this paper. After the black silicon is formed in reactive ion etching, SU-8 mold is fabricated on top of the black silicon that has nano-sized holes. After the microfabrication of SU-8 photoresist mold, poly-dimethygloxane (PDMS) is poured into the mold. As a result, the molded PDMS surface has both micro- and nano-sized structures, which is similar to lotus leaf. The diameter of cylindrical pillar microstructures ranges from 50 to 100 mu m. The water contact angle of 150 degrees is obtained on the molded PDMS surface with pillars diameter of 50 mu m. The superhydrophobic surface made of micro- and nanostructures is straightforwardly formed, increasing water contact angle on the engineered surface.