Light-induced Phase Transition of Lyotropic Liquid Crystals and Motion Behavior of Micron Objects via Photochemical Azobenzene Molecules

Abstract

Abstract. Ternary lyotropic liquid crystal (LLC), was prepared by mixing tetradecyltrimethylamonium bromide (MTAB), water and azobenzene (Az). The phase transition of the LLC was induced from LC phase to isotropic (I) one upon Ar+ laser, which was owing to the trans-cis-trans phoisomerizaion cycle of Az during the irradiation. After that, the LC phase gradually recovered from I phase to nematic (N) phase when being exposed to dark condition. It was also suggested that the recovery time from I to N was different with the Az structures, temperature and ratio of MTAB/Az in the ternary system. Then, the effect of light irradiation on the motion behavior of micron objects dispersed in the ternary LLC film was studied. It was found that the micron objects which dispersed in the irradiated area moved toward the center of the irradiated area, while the micron objects which dispersed around the irradiated area moved away from the irradiated area.