Orientational order and elastic constants of some cyanobiphenyls: Part III

Abstract

In continuation of our previous work, we report here the elastic constants, order parameters and densities of 4'-n-octyloxy-4-cyanobiphenyl (8 OCB) and two of its mixtures with 7 CB. All the three systems exhibit smectic A and nematic phases. The nematic range increases and the A-N transition entropy decreases as the 7 CB content increases in the mixture. Both k,, and k,, exhibit pretransition increases as the N-A point is approached. Though the experimental set up was not adequate for precise determinations of the critical indices (γ), the estimates of γ exhibit a trend which is of qualitative significance.