Multi-responsive microgels: 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. The aim of this experiment is to simultaneously explore the slowing down of the dynamics and how this is correlated to structural changes of the system approaching the glass transition. The use of the new portable DLS-SANS apparatus we have pioneered and recently made available at ISIS will allow us to perform this study never carried out not only in microgels but also in other soft matter systems.