Radii of Gyration of Ring-Shaped Polystyrenes with High Purity in Dilute Solutions.

Abstract

Ring polystyrenes (PSs) were synthesized by anionic polymerization technique and purified with preparative size-exclusion chromatography (SEC). Seven ring PSs with their weight-average molecular weight (Mw) ranging from 17k to 570k were prepared and they were confirmed to have high purities all over 96% by liquid chromatography at the chromatographic critical condition (LCCC) analyses. Their radii of gyration (Rgs) were determined in benzene-d6 as a good solvent and in cyclohexane-d12 or cyclohexane-h12 as Θ solvents by small-angle neutron scattering (SANS) or light scattering (LS). It has been found that Rgs of ring polymers are scaled with Mw as Rg∝Mw0.60 in a good solvent and as Rg∝Mw0.53 in Θ solvents. Moreover it was confirmed that g factors, Rg2(Ring)/Rg2(Linear), obtained in Θ solvents are meaningfully larger than theoretically predicted values owing to the topological effect stored in ring molecules.