Photochemically Induced Isothermal Phase Transition in Liquid Crystals. Effect of Interaction of Photoresponsive Molecules with Matrix Mesogens

Abstract

The photoinduced phase transition behavior of liquid crystals (LCs) was investigated. The rate of the phase transition increased with increasing temperature and decreasing cell gap. The amount of isomerization of photoresponsive molecules to induce the phase transition was found to depend on the LC forming force and affinity of the photoresponsive molecule with the host mesogen. A larger amount of isomerization was required to induce the phase transition of LC matrix with higher T _NI or ΔS. Mesogenic azobenzene derivatives induced the phase transition effectively. These results indicate that the interaction between photoresponsive molecules and matrix mesogens is an important factor affecting the isothermal phase transition behavior.