Amorphous SiO2 films were deposited by means of an electrospray technique. The relation between the water contact angle (WCA) of the deposited SiO2 films and the surface morphology is investigated. The feeding rate of the electrospray process greatly affects the morphology of the synthesized SiO2 films. There is also a significant change in the WCA on the surface of the films: the rougher the surface, the greater the WCA. A model based on the Cassie–Baxter formulation is used to explain the change observed in the WCA on the SiO2 films. Copyright © 2012 John Wiley & Sons, Ltd.