DMR Study of Molecular Order In A Reentrant Nematic Liquid Crystal

Abstract
We report on the measurement of molecular orientational order parameter Q of a perdeuterated 60CB molecule in a binary mixture of 60CB/80CB by means of deuterium quadrupolar splittings. The temperature variation of Q, both of the aromatic and the alkyl deuterons, behaves smoothly through the nematic, smectic A and reentrant nematic phases. These data are in contrast with the prediction of the molecular theory of McMillan-type and the phenomenological theory of Landau-type.