First-order Structure and Solution Properties of Monodisperse Graftcopolymers as Studied by Light Scattering

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In this study, the following three types of graftcoplymers were synthesized and their solution properties were investigated: (1) Star-shaped polystyrene having a portionally deuterated arm; (2) Star-shaped polystyrene having a chemically-different arm; (3) Block-graftcopolymer with many grafted chains near the middle part of the stem.(1) Small-angle neutron scattering from the inner- and outer- labeled stars in CS2 were measured. The data analysis has allowed us to make the following conclusions. (A) Inner part of an arm chain in the star-shaped polymer is more expanded by about 2 times than the outer part of the arm. (B) Structure function of real star-shaped polymers is far from that of the Gaussian star, having large segmental pairwise correlation at short distances near the center.(2) This was synthesized for light-scattering measurements corresponding to the issuer (1). First, we made a diblockcopolymer consisting of poly(2-vinlynaphthalene), which would be a chemically-different arm, and poly(4- vinylphenyldimethylvinylsilane), which would be the center polymer. Then, living polystyrenes were coupled with the center polymer to be the arms of star.(3) The stem polymer was polystyrene, while the grafted polymer was polyethylene glycol. The copolymer formed a large micelle in a selective solvent, 1-methylcyclohexanol. The critical micelle concentration depends strongly on the temperature in the range of 30 - 45ﾟC. Experimental results of apparent molecular weight, radius of gyration, hydrodynamic radius, and scattering function suggest that the micelle may be nonuniform in size and shape, being rather rod-shaped in the initial stage of micelle formation and grow up to be hollow spherical or disshaped at the equilibrium.