Multi-responsive microgels of PNIPAM and Poly(acrylic) acid: simultaneous structure and dynamics

We propose to investigate a temperature and pH responsive microgel composed of Interpenetrating Polymer Networks (IPN) of poly(N-isopropylacrylamide) (PNIPAM) and Poly(acrylic) acid (PAAc). Our group has investigated the behaviour of both PNIPAM and IPN microgels as a function of temperature, concentration, pH and acrylic acid content, by combining DLS, XPCS, SANS, SAXS, TEM, Raman and IR spectroscopy, rheology, calorimetry and electrophoretic measurements. Using the new portable DLS-SANS apparatus we have pioneered and recently made available at ISIS we have very recently successfully explored the simultaneous evolution of the dynamics and the structure of the system approaching the glass transition. We want now correlate the softness of the system (that we can change ad hoc through the PAAc content) with the corresponding evolution of the dynamics and the structure simultaneously measured through the DLS-SANS setup. This will allow us to attain a better understanding of the differences between colloidal and structural glasses.