The synthesis of polystyrene (PS) brushes on fully deuterated PS nanoparticles by surface-initiated nitroxide-mediated radical polymerization (SI-NMRP) is reported. Due to the high demand of deuterated monomers, an effi cient deuteration procedure of suitable and readily available precursors is developed. SI-NMRP of styrene is improved regarding reaction control, grafting density, and conversion. Insights into the scaling behavior and conformational features of surface-attached PS chains on deuterated particles are investigated by using dynamic light scattering measurements, proving that polymer brushes are formed. The particles with surface-attached initiator are shown to be uniform spherical core-shell particles by small-angle neutron scattering measurements.

We previously reported that grafted polystyrene (PS) chains on silica nanoparticles at a low grafting density show similar conformations to free PS chains in the same solvent, THF (diameter ∼50 nm, Colloid.poly.Sci. (2013), 291, 9, 2087-2099. As an extension of our previous study we choose an organic nanoparticle (deuterated polystyrene, dPS) instead of inorganic nanoparticle to see the impact of the substrate material on chain conformation. Additionally, a wider range of molecular weights were prepared to investigate the conformation feature of grafted PS chains more in detail. Small angle neutron scattering (SANS) experiments were performed to characterize PS grafted dPS particles in good solvent condition, with deuterated toluene and deuterated THF as solvent. To get insight into the conformation of the grafted PS layer we apply a scaling law describing the dimension of free PS polymer in good solvent condition to the obtained thickness of the grafted PS layer. We find an overall agreement with the scaling law where the thickness of the grafted PS layer is slightly larger than 2R g of the free polymer chains in the respective solvent giving hint for semi dilute polymer brush (SDPB) situation.