Molecular dynamical simulation of structure formation after nanodroplet spreading over heterogeneous surfaces

Simple (Lennard-Jones) and polymer nanosized droplet spreading over structured (heterogeneous) solid substrates has been simulated on the basis of isothermal molecular dynamics. Three types of modeling substrates with mesoscopic nanosized heterogeneities have been used: stripped surfaces, high-energy surfaces with regularly quadratic low-energy inclusions and low-energy ones with quadratic high-energy inclusions. It has been shown that spreading kinetics and final droplet configurations may be greatly influenced by the mesoscopic structure of the substrate. It has been also found that the macroscopic Cassie law is not always qualitatively satisfied for a substrate with mesoscopic heterogeneities.