Is it Possible to Change Wettability of Hydrophilic Surface by Changing Its Roughness?

Wetting behavior of model rough surfaces made of hydrophilic square pillars is investigated. The hydrophilic pillars are equally spaced on hydrophilic surface. The surface roughnesses are altered by varying the pillar width and interpillar spacing. Wetting to dewetting transition is observed for these surfaces. This is one of the first accounts of observation from molecular simulations where hydrophilic surface converts into hydrophobic by changing its roughness. The extent of hydrophilicities are also changed to gain more insightful observations. Energies of the wetting to dewetting transitions are analyzed by calculating the contribution from water–water and water–surface energy components. A correlation between energy and the wetting to dewetting transition has been established, which rationally explains the observed water repellent nature of hydrophilic surface as a function of roughness.