Effect of molecular-scale surface morphology on the surface melting of liquid crysals on self-assembly monolayers

Abstract

We devised liquid crystal cell substrates with different surface roughnesses at the molecular scale by controlling the density of two types of trichlorosilanes with different alkyl chain lengths. We investigated surface melting of liquid crystals on these surfaces by observing the anchoring transition (change in the direction of alignment) that usually accompanies surface melting. Surface melting was observed only on substrates that had undulating surface morphologies due to either a low molecular density or interspersed arrangement of the two types of trichlorosilanes. We attributed the surface melting to the influence of molecular-level surface roughness on liquid crystal order parameters near the surface