Radical crossover reactions of alkoxyamine-based dynamic covalent polymer brushes on nanoparticles and the effect on their dispersibility

A polymer brush with exchangeable alkoxyamine side chains was prepared by surface-initiated atom transfer radical polymerization on silica nanoparticles. Fluorinated and ionic polymers were grafted to the polymer brush and the grafted side chains could be detached from the surface of the nanoparticles via radical exchange reactions of alkoxyamine moieties. The chemical composition of the polymer brushes on nanoparticles before and after the exchange reactions was investigated by X-ray photoelectron spectroscopy. The dispersibility of the nanoparticles in solution could be changed by the reversible grafting reactions.