Revisit to phase diagram of poly(N-isopropylacrylamide) microgel suspensions by mechanical spectroscopy

摘要: Microgels are soft particles that can be deformed and compressed, which would induce intriguing phase behaviors at high packing fractions. Poly(N-isopropylacrylamide) (PNIPAM) microgels, with a lower critical solution temperature (LCST) of 33 °C, have attracted considerable interests as model colloids, since the volume them interaction between microgels tuned precisely by temperature. In this work, linear viscoelastic properties PNIPAM microgel suspensions been investigated using mechanical spectroscopy. A particular attention is focused on concentrations. With increasing concentration system undergoes repulsive glass-to-gel transition below LCST, while, raised across gel-to-attractive glass transition. mechanism these transitions for proposed based directional particles. moderate or de-swelling isotropic leading to phase, while in concentrated gel phase. Our results enrich current understanding systems shed new light diagram colloidal general.