Structural features of star-shaped fullerene (C60)-containing polystyrenes: Neutron scattering experiments

Structural features of star-shaped polyprotostyrene and polydeuterostyrene containing fullerene C60 as a branching center have been studied by small-angle neutron scattering in benzene solutions. The results are compared with the corresponding characteristics of linear PSs, the molecular mass of which is equal to the molecular mass of one star arm in star-shaped macromolecules. The molecular masses of star-shaped polymers are estimated, and their branching center is shown to be hexafunctional. At relatively low concentrations of starshaped polymers in solutions, one can observe excluded volume effects, which are related by the presence of regions with higher densities at the center of a macromolecule. Using the Fourier transform of the scattering cross section, three-dimensional correlation functions are obtained, and the regular structure of stars is proved. Conclusions about the local correlations of units within one star arm and averaged correlations between units of neighboring arms within a given star are derived. An analysis of three-dimensional correlations shows that the centers of mass of all star arms are directed along orthogonal axes passing through the C60 branching center of a star-shaped macromolecule.