Multiscale approach optimization on surface wettability change on rough surface

Surface wettability is known that is not only governed by chemical structure but also by the surface geometrical structure. A multiscale approach on rough surface wettability study was presented in this paper. The wettability study of photo-switched trans and cis isomers of azobenzene on different substrates was first calculated by molecular dynamics calculations. Different chemical structures and configurations were input into the molecular model to get equilibrated structures. Contact angle is then estimated and input into finite element model with roughness factor included. The parameters were input into the FLUENT software to estimate the respective surface wettability for each individual trans and cis configuration on different rough surface. The simulated wettability results were found to be in good correlation with experimental measures. This multiscale approach provides an opportunity to study the combined effects of surface interaction at molecular scale, and micron scale surface roughness, on the wettability of a rough surface. It enables the prediction of contact angle of liquid media on rough surfaces which will be a powerful tool in the selection and optimization of material and substrate surface structure to control the hydrophobicity/hydrophilicity at liquid/solid interface.