Vibrational Spectroscopy of Liquid Crystals

Abstract

This contribution presents some applications of static and time‐resolved vibrational spectroscopy to various liquid crystalline systems including low‐molecular‐weight nematics, ferroelectric and antiferroelectric liquid crystals (LCs), polymeric LCs, guest–host systems, and polymer‐dispersed LCs. Special attention has been paid to an application of time‐resolved Fourier transform infrared (FT‐IR) and Raman spectroscopy to study the electric‐field induced reorientation mechanism of LCs on a molecular level by monitoring the behavior of different functional groups. Most of the experimental results suggest that the low‐molecular‐weight LCs reorient as rigid rods. Regarding the polymeric LCs, only the mesogen and a small part of the spacer participate in the switching, while the rest of the spacer and the main chain do not reorient. An understanding of these molecular motions may lead to the development of better‐performing LC systems.