Helical Polyacetylene-Origins and Synthesis

We present the origins and synthesis of helical polyacetylene (H-PA) by focusing on its peculiar spiral morphology. Interfacial polymerization of acetylene was carried out in an asymmetric reaction field consisting of chiral nematic liquid crystal (N*-LC) and Ziegler-Natta catalyst. As the N*-LC is composed of nematic liquid crystal and a chiral compound such as a binaphthyl derivative with either the R- or S-con figuration, the screw directions of the polyacetylene chain and fibril bundle-and even the spiral morphology are rigorously controlled by the chirality of the selected compound. Interestingly, the screw directions of the fibril and the bundle in H-PA were found to be opposite to that of N*-LC. It is worthwhile to emphasize that the hierarchical spiral morphology involving the primary to higher order structure is generated in a synthetic polymer such as polyacetylene by using N*-LC as an asymmetric polymerization solvent. (c) 2008 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 8: 395-406; 2008: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20163