Elaboration of hybrid silica particles using a diazonium salt chemistry approach

We demonstrate that the reaction of diazonium salts with silica particles in basic media can provide reactive surface functionalities which are able: (i) to initiate the growth of polymers and (ii) to immobilize iron oxide nanoparticles at the surface of silica particles. Using this strategy, we synthesized hybrid >silica core@poly(acrylic acid) shell particles and magnetic hybrid materials composed of silica cores surrounded by a dense covalent attachment of magnetic iron oxide nanoparticles and polyethyleneglycol chains. Advantages of this functionalization approach rely not only on the simplicity, rapidity and efficiency of the procedure but also on the formation of strong silica aryl surface bonds, highly suitable for a wide variety of potential applications in colloid and surface science and technology.