Static and dynamic characterization of droplets on hydrophobic surfaces

Abstract

We report on our study of the static and dynamic wetting property of hydrophobic surfaces with micro- and dual micro/nano-scale structures. Simulations based on the lattice Boltzmann method showed that the apparent contact angle of water droplets on hydrophobic surfaces with micro-scale structures increases as solid area decreases, whereas dual micro/nano-scale structures not only increase surface hydrophobicity but also greatly stabilize the Cassie state of droplets. Droplets falling on a superhydrophobic surface distort and, depending of free energy, sometimes bounced on the surface before finally adhering to the surface. These phenomena are in agreement with experimental observations. Simulated results also show that micro/nano-scale surface structures can increase droplet rebound height, which depends on static apparent contact angle. © 2012 Science China Press and Springer-Verlag Berlin Heidelberg.