Control of the colloidal stability of polymer-grafted-silica nanoparticles obtained by atom transfer radical polymerization

Polymer chains are grafted from silica nanobeads. The method consists in grafting first the initiator molecules on the silica surface. Then, the polymerization of styrene or n-butyl methacrylate using Atom Transfer Radical Polymerization, is conducted. The nanoparticles are kept in Solution during the whole process to avoid irreversible aggregation. The state of dispersion of the grafted silica nanoparticles is followed by Small Angle Neutron Scattering, as well as the quantity and the spatial organisation of the polymer. This is done during the functionalisation and the polymerization, but also after purification where free polymer chains are eliminated. This permits to reach a quantitative level of SANS analysis from these Purified particles, which is compared to chemical data given by Size Exclusion Chromatography and Thermogravimetric analysis.