Phase Transition in Super Thin Liquid Crystal Films

An existence of mesomorphous phase is proved in super thin 20-nm films prepared by Langmuir– Blodgett technique from a smectic liquid crystal material para-tetradecyloxybenzyliden-amino-2methylbutyl-cyanocinnamate. The structural phase transition is registered in the films near 75 C and investigated by a number of methods including molecules adsorption measurements, light reflection and polarization, as well as electrophysical methods. The analysis of experimental data has proven that the observed structural phase transition in the film is the ferroelectric–paraelectric transition. A comparison is made between the super thin and more thick (spin coated) films of the same material. The phase transition is shifting towards lower temperatures with the increase of the film thickness.