A Model for the Contact Angle of Liquid Droplets on Rough Surfaces

Up to now, measured results of the contact angle on rough surfaces have been explained usually based on the Wenzel equation (1936) and the Cassie–Baxter equation (1944). However, these equations do not take into account considerations of liquid wetting behaviors on rough surfaces, and this leads to poor understanding of the mechanisms of contact between liquid droplets and rough surfaces (e.g. contact angle hysteresis). We propose a new model for the contact angle of liquid droplets. By means of the present model, we can well understand the experimental data which could not be well explained by the Wenzel equation and the Cassie–Baxter equation.