The properties of existing polymers can be improved by adding a minor fraction of nanoparticles that are small (nanometer range) in at least one dimension. Block copolymers with a controlled structure will be added as an efficient stabilizer for the nanoparticles. The influence of the microstructure or composition of the block copolymers on its stabilization efficiency will be investigated. In addition various applications for the obtained nanocomposites will be tested.