Π‐Conjugated Helical Nano‐Columnar Polyacetylenes as Novel Color Controllable Materials

Abstract

AbstractA series of p‐n‐alkoxyphenylacetylenes (pROPA)s (R: CnH2n+1, n = 1, 2, 4, 6, 8, 10, 12, and 14) was polymerized with [Rh(norbornadiene)Cl]2 catalyst in the presence of triethylamine to give stereoregular polyacetylenes, which colors of the resulting polymers were changed with increace of the carbon number of the alkyl side chains, i.e., yellow (n = 1∼6), orange (n = 8), red (n = 10), and dark red (n = 12, 14) along. Based on 1H NMR and laser Raman spectra, it was found that the main chain of these polymers was cis‐forms. Wide‐angle X‐ray diffraction (XRD) analysis indicated that yellow polymers were almost amorphous. In the case of the orange polymer, crystallinity, i.e., columnar content, was increased. Red and dark red polymers consisted largely of the columnar. It was concluded that colors of these polymers were strongly correlated with their columnar content. Therefore, the columnar of these stereoregular polyacetylenes can be considered as helical self‐assembly π‐conjugated , i.e., color controllable material.