Retention behavior of polystyrene copolymers having different structures and compositions was investigated for measuring thermal diffusion coefficient (D_T) using thermal field-flow fractionation(ThFFF). Samples were random poly(styrene-co-methylmetha...
Retention behavior of polystyrene copolymers having different structures and compositions was investigated for measuring thermal diffusion coefficient (D_T) using thermal field-flow fractionation(ThFFF). Samples were random poly(styrene-co-methylmethacrylate)s, poly(styrene-co-isoprene) block copolymers having molecular weights ranging from 10^4 to 10^5. It was found that the ThFFF retention of copolymers is related to the composition as well as the molecular size of copolymers. For random copolymers, D_T was a linear function of the monomer composition, and it was possible to determine the molecular weight of polymers by use of calibration curve of log(wt % M[η]) versus log(D/D_T). For block copolymers, D_T values of diblock copolymers were greater than those of triblock. It was found that the thermal diffusion varies with the copolymer structure as well as the composition.