Polarization inversion in a ferroelectric liquid crystal studied by H-1 nuclear magnetic resonance

Abstract

A ferroelectric liquid crystal, S-2-methylbutyl 4-n-octanoyloxybiphenyl-4(')-carboxylate, undergoing a characteristic polarization inversion, has been studied by H-1 nuclear magnetic resonance (NMR). In addition to the discontinuities at the first-order isotropic and recrystallization phase transitions, the nuclear magnetic relaxation revealed a weak anomaly attributed to the soft mode at the Sm-A-Sm-C-* liquid crystalline phase transition. Besides, the polarization inversion in the Sm-C-* phase was manifested in the nuclear magnetic relaxation as well as in the NMR lineshape and in the temperature-dependent relative peak positions of the NMR line components, indicating that the polarization inversion is associated with a conformational transition.