MOLECULAR-CONFORMATION AND ORIENTATION IN SOME SMECTIC C-PHASES

X-ray diffraction measurements are reported on two types of smectic C phases. First, a compound showing very small variation in layer spacing through the smectic A and C phases was studied showing consistency with the normal second order behavior. Second, a homologous series of 4-alkyloxycinnamic acids was studied and some measurements were also made on 4-hexadecyloxybenzoic acid. The cinnamic acid results were analyzed to give information about the gross average molecular conformation in the smectic C phase. The implications of these results for the fast molecular rotations known to occur in smectic C phases are briefly discussed.