Surface induced crystallization of polymeric nano-particles: effect of surface roughness

Molecular dynamics simulations are conducted to study the crystallization of a polymeric system as a drop in an isolated state and on a surface. It is shown that crystallization kinetics for the polymeric system as a particle on a smooth surface is much faster than in the isolated form. We show however that as the surface becomes rough the crystallization rate of the polymeric particle decreases. The effect of roughness was compared for two cases of a polymer drop, partially (Wenzel state) and fully (fully confined) wetting the cavities on a rough surface. In both cases it was observed that crystallization was slower than that on a smooth surface, and crystal growth rate was decreased by increasing the characteristic roughness ratio. The crystallization on rough surfaces was still faster than that of the isolated polymer drop.