Influence of backbone rigidity on the liquid crystallinity of mesogen-containing polyacetylenes

摘要

Two acetylene polymer containing cyanobiphenyl-based mesogens, poly{10-[((4'cyano-4-biphenylyl)oxy)carbonyl]-1-decyne} (PA8CN),which has a relatively flexible polyalkyne backbone, and poly {[4-(((12-((4'-cyano-4-biphenylyl)oxy)dodecyl)oxy) carbonul) phenyl]-acetylene} (PB12CN), which has a fairly rigid poly(phenylacetylene) backbone, were synthesized using respectively WCl_6 and [Rh(nbd)Cl]_2 as the catalysts. PA8CN exhibits enantiotropic interdigitated smectic A phase (S_Ad) over a temperature range a wide as ca. 100deg. C, whereas PB12CN is non-mesomorphic, Demonstrating that the backbone rigidity plays a important role in determining the liquid crystallinity of the polyacetylenes.