Control of Main-Chain Stiffness of a Helical Poly(phenylacetylene) by Switching On and Off the Intramolecular Hydrogen Bonding through Macromolecular Helicity Inversion

摘要

Rodlike helical polymers with an excess of one-handedness arising from an optically active component incorporated into the main chain or at the pendants often show chiral liquidcrystalline (LC) phases in concentrated solutions or in a melt.[1] Since the 1980s, such LC helical polymers have been extensively studied with much interest. Typical biological macromolecules, such as DNA,[2] polysaccharides,[3] and polypeptides,[4] which adopt an ordered structure such as a helical structure, with a controlled helix sense stabilized by intra- and/or intermolecular hydrogen-bonding networks, also exhibit chiral LC phases resulting from the rigid-rod characteristics of the polymer main chains.