Ring patterns in liquid crystals aligned by phase-separated two-component monolayers

We investigate the alignment of 4′-pentyl-4-cynobiphenyl (5CB) liquid crystal on phase-separated two-component organosilane monolayers that consist of the protruding islands surrounded by a continuous phase. The molecular disordering at the protruding island edge locally perturbs the homeotropic alignment of the 5CB induced the phase-separated monolayers, leading to the formation of ring patterns. The edge effect on the 5CB alignment decreases with the decrease of the height difference between the protruding islands and the surrounding monolayer and increases with the decrease of the size of the protruding islands.