Characterization of mixed solutions of hyperbranched and linear polystyrenes by a combination of size-exclusion chromatography and analytical ultracentrifugation

Separation and characterization on mixed solutions of hyperbranched and linear polystyrenes was achieved using size-exclusion chromatography (SEC) as the first dimension and analytical ultracentrifugation (AUC) as the second dimension. The results show that linear and hyperbranched polystyrenes with similar hydrodynamic sizes (one fraction from SEC) can be separated by AUC according to the molar mass, and the separation efficiency decreases with the increasing of the retention volume in SEC. Moreover, the molar masses determined by AUC are consistent with the values measured by SEC-refractive index (RI) and SEC-multi-angle light scattering (MALS) detection. Furthermore, the result shows that the separation efficiency decreases with the increasing of the subchain length of hyperbranched polystyrenes. Our study lays a solid foundation for future studies to separate polymers with different topologies by a combination of SEC and AUC.