Solution properties of semirigid polyquinolines. I. Size-exclusion chromatography with light-scattering detection of poly[2,2′-(P,P′-oxydi-P-phenylene) 6,6′-oxybis(4-phenylquinoline)]

An aromatic semirigid polyquinoline, poly2,2′-(p,p′-oxydi-p-phenylene) 6,6′-oxybis(4-phenylquinoline)], has been studied in dilute solution using viscometry, light scattering, and size-exclusion chromatography coupled with low-angle light-scattering detection (SEC/LALS). The SEC/LALS technique permits determination of the intrinsic viscosity and absolute molecular weight for a series of narrow fractions without preparative fractionation. Aggregation that was observed in dilute chloroform solutions was found to be related to protonation of the polyquinoline by HCI present in chloroform. Unperturbed dimensions calculated from the SEC/LALS results show the chain to have nearly freely rotating dimensions, as expected for a chain composed of long (12-Å) rigid segments connected by ether linkages.