Pyrrole- and polypyrrole-based liquid crystals

In this paper we report one of the first examples of a soluble, fusible liquid crystalline polypyrrole. We describe the synthesis and characterisation of two pyrrole-based monomers substituted at the N-position with the mesogenic group 4-cyanobiphenyl. The mesogenic group is separated from the pyrrole moiety by an alkyl chain of either 3 or 11 methylene units length. We discuss the spectroscopic and thermotropic properties of these monomers and describe their oxidative polymerisation using electrochemical methods and separately using FeCl3 and I-2 as chemical oxidants.