Molecular Dynamics Simulation of Wetting on Wavelike Nanorough Surfaces

Abstract

A Molecular Dynamics (MD) technique is proposed to simulate the motion of water nanodroplets on wavelike nanorough surfaces and the contact angle is evaluated. Results obtained through MD simulations, in agreement with the experimental evidence, suggest that the contact angle can be increased by folding the base surface, to produce a wavelike nanoroughness. By considering the fraction of nonwetted area as a function of the ratio of true area to projected area, it becomes possible to fit the results obtained through MD simulations on a generalized Wenzel-Cassie model, even in the nanometer range. The physical meaning of such fitting technique is discussed. Results obtained are useful for the appropriate design of the hydrophobic or hydrophilic surfaces, and for the adequate design of nanorough surfaces with tribological applications.

Keywords

• molecular dynamics
• wetting
• wavelike nanorough surface
• water
• wenzel-cassie model