Wetting Phenomena (To be updated)

The wetting behaviour of liquids on solid surfaces plays an important role for a wide range of problems, including oil recovery, microfluidics, inkjet printing, and consumer products. For many of these applications, the key challenge is to control the wettability of a given substrate against various liquids. To achieve such control, especially over the full range of contact angle values (wetting landscape), surface chemistry, while crucial, is inadequate by itself. Additional 'handles' are required, which can be provided by the geometry and elasticity of the substrate.

Our group develops lattice Boltzmann simulation method (with J.M. Yeomans in Oxford and T. Krüger in Edinburgh) to study the equilibrium morphologies and dynamics of liquid droplets on elastic and structured substrates. In the past we have addressed the problems of contact line pinning, contact angle hysteresis, and how they can be exploited for the designs of superhydrophobic and smart surfaces. Currently, we are working with P&G Cincinnati (M. Wagner and Y. Gizaw) and Northumbria University (G. McHale)  to study the dynamics of droplets on SLIPS and deformable surfaces.

Below are two movies: (i) The liquid droplet undergoes a Cassie to Wenzel transition as it evaporates. This transition is driven by the Laplace pressure. (ii) A liquid droplet spreading on a chemically striped surface.