Facile preparation of superhydrophobic coatings by sol–gel processes

Different organic/inorganic compositions and deposition methods were used to prepare superhydrophobic surfaces using metal alkoxides and the sol–gel process. Both surface roughness and composition had to be adjusted in order to obtain very high contact angles and low contact angle hysteresis as a necessary requirement for superhydrophobicity. Multilayer samples with a fluorinated organic–inorganic top layer showed water contact angles of about 157° with low hysteresis (2°). Water drops rolled easily off their surface at a tilt angle as low as 4°.