FOURIER-TRANSFORM INFRARED STUDY OF 2 TRUXENE-BASED DISCOTIC LIQUID-CRYSTALS

We have used FTIR absorption to study the crystalline and liquid-crystalline phases of 2,3,7,8,12,13-hexa-n-tetradecanoyloxy-truxene (HATX) and 2,3,7,8,12,13-hexa(4-n-undecyloxybenzoyloxy)truxene (HBTX). Both materials show pronounced changes in the CH2 stretching mode frequencies at their melting points. In addition, HATX shows a transition at about 20°C below the nominal melting point in which the alkyl tails gain significant disorder. Benzene stretching modes and the CH2 deformation modes show subtle changes at the D>rd → N transition of HBTX and at the Drd→ Dhd transition of HATX. © 1990 Taylor & Francis Group, LLC.