Investigation of a partially fluorinated chiral antiferroelectric liquid crystalline material with large negative dielectric anisotropy

Abstract

Liquid crystal is a state of matter that has both liquid-like fluidity and crystal-like ordering in varying degrees. In this work, we study 4-{[(2S)-octan-2-yloxy]carbonyl}phenyl4′-{4-[(2,2,3,3,4,4,4-heptafluorobutanoyl)oxy]butoxy}-[1,1′-biphenyl]-4-carboxylate, a partially fluorinated chiral liquid crystalline compound. The mesomorphic studies of the compound highlight the existence of polar smectic phases. The molecular geometry, chemical reactivity, nonlinear optics, and charge dynamics are investigated by density functional theoretical calculations. The structural characterization of the compound is performed through vibrational spectroscopy. Dielectric spectroscopy highlights five collective relaxation processes that perfectly fit the modified Cole-Cole relaxation model. The compound 3F4Bi exhibits a bandgap of 4.05 eV, high birefringence (0.16), optical nonlinearity, and a large negative dielectric anisotropy for the tilted ferroelectric phase. The compound could be used as an optically active component to form ferroelectric multi-component mixtures.