Fabrication of Superhydrophobic Coatings on Glass based on Poly(dimethylsiloxane) and Fumed Silica

Abstract

This study reports the preparation of superhydrophobic covalently attached poly(dimethysiloxane)(PDMS)/fumed silica composite coatings on glass via spin-coating and subsequent heating. The effect of PDMS molecular weight and fumed silica type (hydrophilic and three different hydrophobic) on the wettability and morphology were studied in detail and the wettability and morphology of the coatings were characterized by contact angle measurements and scanning electron microscopy (SEM). Superhydrophobic coatings which have advancing contact angles of 172-174° and contact angle hysteresis (CAH) as low as 7-8° were obtained using 4% (w/v) PDMS modified hydrophobic fumed silica and all kinds of PDMS. The surfaces which were prepared by 4% (w/v) hydrophilic and dimethylsiloxy modified fumed silica had high advancing contact angles of 163-168° but the CAH on these surfaces were higher than the ones prepared using PDMS modified fumed silica. This can be ascribed to the incompatibility of the hydrophilic and dimethylsiloxy modified fumed silica with the PDMS matrix which was also confirmed with the SEM results.