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

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 (M-w) 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 (R-g(s)) were determined in benzene-d(6) as a good solvent and in cyclohexane-d(12) or cyclohexane-h(12) as 0 solvents by small-angle neutron scattering (SANS) or light scattering (LS). It has been found that R-g(s) of ring polymers are scaled with M-w as R-g proportional to M-w(0.60) in a good solvent and as R-g proportional to M-w(0.53) in Theta solvents. Moreover it was confirmed that g factors, R-g((Ring))2/R-g((Linear))2, obtained in Theta solvents are meaningfully larger than theoretically predicted values owing to the topological effect stored in ring molecules.