Small Angle Neutron Scattering of Arborescent Graft Polymer Solutions

Abstract

Small Angle Neutron Scattering (SANS) was used to characterize the size and shape of generation 3 and generation 4 polystyrene (PS) based arborescent graft polymers where the final generation of the polymer molecule composed of deuterated PS. Contrast variation techniques were used to match the solvent to the either the PS core or the deuterated PS shell. A core-shell model was used to fit the SANS data with good success. Density profiles of generation 4 and generation 3 arborescent graft polymers in different solvents are calculated, and the size of the molecule is found to be dominated by the solvent quality. The radius of gyration is found to be determined by the scattering length density of core and shell, core radius and total hydrodynamic radius. The radius of gyration from Guinier plot is discussed and found unreliable due to non-uniform density distribution of the molecule.