X-RAY-DIFFRACTION STUDIES OF THE LIQUID-CRYSTAL PHASES OF CERTAIN 4-N-ALKOXYPHENYL 4-(5-N-ALKYL-2-THIENYL)BENZOATES

The n-butyl, n-octyl, n-decyl and n-dodecyl homologues of each of the 4-n-pentyloxyphenyl, 4-n-hexyloxyphenyl and 4-n-heptyloxyphenyl 4-(5-n-alkyl-2-thienyl)benzoates have been prepared. All the homologues give rise to liquid crystal phases and their transition temperatures are reported. Phase identification was not straightforward, especially when distinguishing between some of the higher order smectic phases, and required a combination of thermal optical microscopy and X-ray diffraction studies, including powder photographs and detailed measurements of smectic layer spacings.