Elastic constants and orientational viscosities of a bent-core nematic liquid crystal

Abstract

Using a combination of dynamic light scattering and Freedericksz transitions induced in applied magnetic and electric fields, we have determined the absolute magnitudes of the Frank elastic constants and effective orientational viscosities of the bent-core nematic liquid crystal, 4-chloro-1,3-phenylene bis 4-[4'-(9-decenyloxy)benzoyloxy] benzoate. At a fixed temperature 2 °C below the isotropic-nematic transition, we find K₁₁ = 3.1 x 10⁻¹² N, K₂₂ = 0.31 x 10⁻¹² N, K₃₃ = 0.88 x 10⁻¹² N, η{splay}=1.1 Pa s, η{twist}=0.37 Pa s, and η{bend}=1.2 Pa s. The unusual anisotropies of these parameters are discussed in terms of short-range, smectic-C-like correlations among molecules in the nematic phase.