Amplification of macromolecular helicity of dynamic helical poly(phenylacetylene)s bearing non-racemic alanine pendants in dilute solution, liquid crystal and two-dimensional crystal

Optically active poly(phenylacetylene) copolymers composed of non-racemic phenylacetylenes bearing L- and D-alanine decyl esters as the side groups (poly(1Lm-co-1Dn), m>n) were prepared by the copolymerization of the corresponding L- and D-phenylacetylenes with different enantiomeric excesses using a rhodium catalyst; their chiral amplification of the helical conformation as an excess of one-handedness in a dilute solution, in a lyotropic liquid-crystalline (LC) state and in a two-dimensional (2D) crystal on substrate was investigated by measuring the circular dichroism spectra of the copolymers at different temperatures, mesoscopic cholesteric twist in the LC state (cholesteric helical pitch) and high-resolution atomic force microscopy images of the self-assembled 2D helix-bundle structures of the copolymer chains, respectively.