The context of the study is to design Nanocomposites with well defined and controlled polymer/particle interfaces to understand more deeply the interfacial contributions on the macroscopic properties in Nanocomposites. We adapted a previous work of conventionnal polystyrene (PS) silica grafted nanocomposites on the controlled synthesis (ATRP and NMP) of silica particles grafted with photo-cleavable polymer chains (PS). The aims of the proposal is first to characterize with SANS the grafted particles in solution using silica core contrast matched with mixtures of solvent. Then, we will apply different duration of UV radiation on the solution for de-grafting the chains from the particles and follow the scattering intensity. Finally, we will mixed the photo-cleavable particles with free PS chains to make a film with a specific matrix whose scattering length density matches the silica particles. We can thus determine the conformation of the grafted chains inside the nanocomposites and see how this conformation evoluate under UV radiations.