화학공학소재연구정보센터
Molecular Crystals and Liquid Crystals, Vol.475, 73-83, 2007
Memory effects and multistability in alignment of nematics at surfaces with inhomogeneous random anchoring
Alignment mechanisms for nematics at a macroscopically isotropic polymer surface are studied in cells where the second surface provides strong anchoring. Surface morphology of tested surfaces was studied using Atomic Force Microscopy and Scanning Electron Microscopy. We observed in polarizing microscope that the temperature gradient across the cell during transition from isotropic to nematic state strongly affects the alignment at the tested surface. We present a model that explains the temperature gradient effect. The initial patterns formed at the tested surface recover after multiple phase transitions but they can be erased by the temperature exposure well above the nematic-isotropic transition.