DIFFUSION AND SEDIMENTATION STUDIES ON POLY(MACROMONOMER) IN DILUTE-SOLUTION

Dynamic light scattering and sedimentation velocity measurements were performed on dilute benzene solutions of poly(macromonomer) with poly( methyl methacrylate) (PMMA) as the backbone chain and polystyrene (PS) as branches to obtain the diffusion coefficient D and the sedimentati on coefficient s, respectively. Dependences of D and s at infinite dil ution on the backbone chain length as well as the branch length were f ound to be quantitatively described by the prolate ellipsoid model wit h values of the main and the minor axis calculated from the planar zig zag PMMA backbone and the gaussian PS branched chains, respectively. A pplication of the wormlike cylinder model gave the Kuhn's statistical length lambda(-1) similar to 90 nm, which is substantially larger than lambda(-1) = 3.2 nm of homo-PMMA. The concentration coefficient of D and s also showed unique dependences on the backbone chain length as w ell as the branch length.