The synthesis of novel polymers obtained by grafting poly(dimethyl siloxane) with NIPAM, N,N'-dimethyl acrylamide (DMA) and copolymers of NIPAM with DMA and butyl acrylate using SET-LRP technique is presented. The polymers were characterized by H-1 NMR, fluorescence spectroscopy, and DSC. The thermo-sensitivity and the LCST as well as the aggregation phenomena during phase transition are evidenced by dynamic light scattering (DLS) and rheology coupled with small angle light scattering (SALS). Rheological and Rheo-SALS measurements proved to be useful tools to characterize the macroscopic behavior but also to evidence structural changes below and above the LCST for the analyzed systems. Good correlation was found between rheological, rheo-SALS and DLS data.