Oligo-side chain liquid crystal polymers: comb polymers with long chiral teeth

The authors have synthesized a new variety of side chain liquid crystal polymers we term oligo-side chain LCP's. The macromolecules of these materials are comb-shaped and differ from conventional side chain LCP's in that the comb's teeth are longer and semiflexible. The oligomeric side chains contain a long flexible spacer not only at their junction with the backbone but also in the center of the mesogen. Specific features of the systems described include monosubstitution of enantiotopic protons in the central spacer by a cyano group and a long alkoxy tail at the terminus; both the configurationally disordered and the enantiomerically enriched comb polymers have been synthesized. An interesting and unusual property of these materials is a lower liquid crystal-isotropic transition temperature relative to that of their monomeric precursors.