Density and Susceptibility Measurements on a Micellar Nematic System

Abstract

The densities and diamagnetic susceptibilities in the nematic and isotropic ranges of two mixtures of decylammonium chloride, ammonium chloride, and water are reported. The mixtures have a lamellar smectic phase, a nematic phase, and an isotropic micellar solution. The smectic-nematic transition is second order, the nematic-isotropic transition first order. The density does not show a discontinuous change at the nematicisotropic transition, and the expansion coefficients of the nematic and isotropic regions are the same within error limits. The diamagnetic susceptibility in the isotropic range and the susceptibility perpendicular to the optical axis in the nematic range were determined using the Gouy method. The diamagnetic anisotropy of the nematic range was derived. It varies from 2 X10⁻⁹ near the nematic-isotropic transition to 5 × 10⁻⁹ cgs near the nematic-smectic transition.