Stabilised columnar mesophases formed by 1 : 1 mixtures of hexaalkoxytriphenylenes with a hexaphenyltriphenylene-based polymer

Abstract

The synthesis is reported for a main chain polymer in which the repeat units are 2,3,6,7,10,11-hexaphenyltriphenylene moieties linked through flexible dodecyl chains. In compositions with a series of 2,3,6,7,10,11-hexakis(alkoxy)triphenylenes (HATn) this new polymer forms stable hexagonal columnar liquid crystal phases. These are investigated in detail using optical polarised microscopy (OPM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). In these mixtures, suppression of crystallisation and enhancement of the clearing temperatures leads to very wide liquid crystal ranges: much wider than those for the HATn materials on their own. For the longer chain HATn compounds (n = 12–16) a columnar rectangular phase is also observed. The enhancement of the liquid crystal phase range is attributed to stabilising complementary polytopic interactions between the planar aromatic moieties.