Olivier Anthony

Formation of hybrid colloids by suspension polycondensation in the presence of hydrophilic block copolymers

Double hydrophilic block copolymers were used to control the growth of inorganic particles and directly prepare hybrid colloidal suspensions. Colloids of metal hydrous oxides were obtained by forced hydrolysis of metal ions in presence of the copolymers. The block copolymers contain a metal-complexing polyelectrolyte block and a stabilizing neutral block. The role of the first block is to ensure a controlled growth of the inorganic phase, while simultaneously, the second block ensures the colloidal stabilization. Phase diagrams presenting the conditions under which precipitation is inhibited are established. The nanoparticles are then characterized in terms of sizes, morphologies and surface charges. The main parameters controlling the size were identified: the copolymer-to-metal ratio and the metal prehydrolysis ratio. The synthesis steps were characterized. First, a key step of induced micellization of the hydrophilic copolymers leads to hybrid core-shell assemblies. The second step consists in mineralization of the micellar core. The suspension polycondensation leads to hairy particles whose morphologies depend on the nature of the metal and on synthesis parameters.