PHASE IDENTIFICATION OF TRIPHENYLENE-BASED DISCOTIC MONOMER AND ITS MAIN-CHAIN POLYMERS

A monomer, 2,3,6,7,10,11-hexakispentyloxy triphenylene (HPT) possesses a triphenylene core as a discotic mesogen. Polymers containing this d iscotic mesogen have been studied using wide-angle X-ray and electron diffraction. HPT is known to show a discotic liquid crystal phase, not ed as D-ho (h for hexagonal bidimensional lattice, o for ordered molec ular spacing in each column). In this paper, however, HPT Liquid cryst alline phases, heated up from the crystalline state and cooled down fr om the isotropic state, were characterized in the diameter dimensions. In addition. the diameters of the columns are close to a parameter of two separate crystals. A core orientation was, therefore, proposed in the mesophase obtained by heating the crystalline. In order to distin guish these differences, the D-ho phase was divided to include the D-h cd and D-hco phases. Molecular modeling was performed to help our unde rstanding of the orientation. The D-hcd and D-hco phases were used to characterize the phases of the discotic polymeric analogs by comparing their column diameters to those of the monomers. (C) 1998 Published b y Elsevier Science Ltd. All rights reserved.