Physico-chemical behavior in solution of star-shaped polystyrene with a C60 core

Fairly pure hexaadducts of molecular weights ranging from 2 x 10(4) to 2 x 10(6) could be prepared by reacting polystyryllithium with C-60 in toluene. These star-shaped polymers, with a fullerene core, associate a low polymolecularity of the arms (I<1.1) and a fairly good control of the functionality (6). Their behavior in toluene has been established using static and dynamic light scattering as well as viscometric measurements. The dimensions of these star-molecules in this good solvent, normalized by the dimensions of the arm or by that of linear polystyrene of same molecular weight, are in agreement with those expected for stars with six arms. Upon decreasing the molecular weight fi-om 2 x 10(6) to 5 x 10(5), an evolution from a random coil type behavior toward that of a dense sphere can be observed. (C) 1998 Elsevier Science Ltd. All rights reserved.