Effect of Bulk Impurities on the Transparency of Cholesteryl Nonanoate

The effect of bulk impurities on the transparency of cholesteryl nonanoate is described. In one variation, the transparency was measured at a fixed incident wavelength (500 nm) as the sample was cooled from the isotropic liquid to the smectic phase. The effects on transition temperature and temperature of maximum dichroic scattering by each of nine solutes at a concentration of 0.5% were determined. The effect of varying the concentration of an added solute (methyl benzilate) was investigated in a similar fashion. In another variation, the dependence of the wavelength of dichroic scattering on concentration of solute was investigated. Combined with results from measurements of the helix pitch and optical anisotropy, these types of data can provide valuable information on the structure of cholesteric materials and on solvent-solute interactions.