Optical anisotropy and local order parameter in a homologous series of cholesteryl esters of fatty acids

Abstract

The paper discusses estimates of local order parameters derived from refractive index data for a homologous series of cholesteryl esters of fatty acids. The local order parameter corresponds to the untwisted nematic structure in the cholesteric phase and, similar to nematogenic compounds, exhibits the well known even-odd alternation with increasing alkyl chain length. The calculated values of the optical anisotropy of the different homologues vary between 3.9 and 6.5 × 10₋₂₄ cm³ indicating that the optical anisotropy arising from alkyl chain is significant when compared to the core contribution.