Temperature and voltage dependence of attenuated total reflection properties of liquid crystal molecules on the LB films

Behaviors of liquid crystal molecules, 5CB, have been investigated in the thick cells having aligning layers of the polyimide (PI) Langmuir-Blodgett (LB) films on the aluminum electrodes using the attenuated total reflection (ATR) measurement method. The ATR curves strongly depended upon the AC voltages applied to the cell and upon temperatures. The resonant excitations of the surface plasmon polariton (SPP) were observed in the broad region of the incident angle in the ATR measurements. The tilt angles of the liquid crystal molecules were calculated by fitting the theoretical ATR curves to the experimental ones. The results showed that the ATR measurement method was very useful for evaluating the behaviors of liquid crystal molecules in thick cells.