The scope of the proposed project is to investigate the shear response of novel soft materials with controlled interaction potential yielding behavior in the intermediate regime between hard colloidal spheres and polymers. We plan to investigate the dynamics and structural rearrangements of highly concentrated suspensions, glasses and gels made of model soft spheres such as thermosensitive microgel particles and multiarm star polymers, subjected to a periodic shear strain. Probing the colloidal motion by Dynamic Light Scattering of suspensions of particles with variable softness we aim at addressing the role of inter particle interactions in the mechanisms of flow, shear melting and yielding of textured soft materials, as well as elucidating the mechanisms and potential differences of gels and glasses. The question of the reversibility of the colloidal motion, and thus the degree of rearrangement of the suspension below and above the yield strain, will be examined. The technique of Light Scattering Echo technique will be implemented in a commercial strain controlled rheometeravailable in the Host Institute to facilitate simultaneous scattering and rheological measurements. A separate shear cell and LS Echo set-up will also be built based on the experience the applicant gained during the initial fellowship. The anticipated impact to the host institute is high. The proposed technique will complement the already wide range of dynamic experimental facilities for probing complex fluids. This will bring an entirely new dimension to the lab's activities and add a world-class methodology to study such systems; the lab will be unique in terms of the range of techniques available. Further, the experience of the applicant in colloids and colloid-polymer mixtures, obtained in one of the leading institutes for colloidal science worldwide is much needed not only in FORTH but in Greece in general where almost no activity in colloidal science exists. It will advance a great deal the understanding of this class of systems and the progress of this lab in the physics of soft matter. Both the applicant and the Host Institute consider the return fellowship as the begging of along-term collaboration rather than merely a one-year project.