Raspberry-like superhydrophobic silica coatings with self-cleaning properties

Here we report, an easy, straightforward and novel way to prepare raspberry-like superhydrophobic silica coatings for self-cleaning applications. The hydrophobic silica particles were obtained by simple condensation of fluoroalkoxysilane (17FTMS) in ethanol at room temperature. These silica particles were embedded into the sol–gel processed silica matrix and deposited on glass plates. On this coating surface, water drops exhibited a contact angle of 152° and rolls off the surface at sliding angle of 10°. This extremely low sliding angle was employed to self-clean the superhydrophobic coating, where dirt particles accumulated on the surface of superhydrophobic coating was efficiently cleaned by quickly sliding water drops. The stability of the microstructure as well as the wetting properties of the coating surface was investigated by scratch resistance and water stream impact test. The superhydrophobic coatings endured against the scratch of applied force of ~150 mN. Such one pot synthesis of raspberry-like superhydrophobic silica coatings may open new avenue in the sublime field of superhydrophobic research.