Influence of chirality on the mesophase of side chain polymers with phenyl benzoate pendant groups

Abstract

To reveal the structure of an amorphous mesophase with a hidden liquid crystalline structure (ISm*) in a chiral side chain polymer, P8*M, its racemic isomer has been synthesized along with two more RS‐copolymers with controlled enantiomer excess. The phase behaviour of the copolymers was studied comparatively by DSC and X‐ray scattering. Optical rotatory dichroism was measured for thin films of P8*M and two homologue polymers, differing in the polymeric main chain, by the size of the chiral terminal group and by its absolute configuration. A helical superstructure with pitch of about 250 nm is indicated within the ISm* mesophase. Its structure as a short pitch TGB phase hase been proven conclusively.

Acknowledgements

The author is greatly indebted to Prof. W.Haase (Institute of Physical Chemistry, Darmstadt University of Technology, Darmstadt, Germany) and Prof. H.‐G. Kuball (Institute of Physical Chemistry, University Kaiserslautern, Kaiserslautern, Germany) for their hospitality, valuable discussions, and support in chemical synthesis and X‐ray measurements (WH) and ORD measurements (HGK). The assistance of Dr B.Helgee (Institute of Polymer Technology, Chalmers University of Technology, Göteborg, Sweden) in DSC measurements is also acknowledged. This work was supported by the Volkswagen Foundation (Germany), Project I 74 471, and by the Deutsche Forschungsgemeinschaft (DFG, Germany), project Re 923–8.