Miscibility between the Smectic A Phase of A Conventional Liquid Crystal and the Lamellar Phase of an Inverse Salt

The isobaric phase diagram of a binary system is presented which gives evidence that the smectic A phase of a conventional liquid crystal is completely miscible with the lamellar phase of an inverse salt. With respect to the rule of selective miscibility the latter therefore corresponds to the phase type smectic A. According to X-ray measurements in the salt component as well as in the mixtures the layer spacings d of the smectic A phase are clearly smaller than the molecular lengths resp. the average molecular lengths. A packing model is proposed for interpreting the experimental results.