Effects of polymer surface structures on liquid crystal alignment studied with molecular dynamics simulations

Abstract Effects of polymer surface structures on surface alignment of liquid crystal molecules were studied by comparison with our previous results of molecular dynamics simulations. An adsorption-related liquid crystal molecule alignment on the packed polyimide surface was found in the simulation study. In this article, we first compared the alignment on a sparse polyimide surface with the previous results of the packed polyimide surface to see effects of polymer surface density. The excluded volume effect with the polyimide domain edges additionally contributed to alignment of the liquid crystal molecules on the sparse surface, and resulted in a similar alignment structure (i.e. alignment direction and tilt angle) to the packed cases. Secondly, we made similar simulations by changing the polymer from a polyimide to a polyamide with similar polymer chain density. Differences between the corresponding packed polyimide case were found mainly in the energetics (the polyamide had about two thirds of the ads...