Swel领 behavior of poly- N-isopropylacrylamide mic

It has been shown that the swel领 of poly-N-isopropyl-acrylamide (poly-NIPAM) microgel particles can be controlled by the addition of alcohols, in addition to the previously observed effect of temperature. The degree of swel领 is also controlled by the amount of cross-linker within the microgel particles. At 25?°C, poly-NIPAM microgel particles collapse upon the addition of MeOH, EtOH and 2-PrOH to a minimum size and then, reswell again as the alcohol-rich region is approached. This trend was also observed for poly-NIPAM microgel particles dispersed in 2-PrOH/water mixtures upon heating to 50?°C. The particles, dispersed in either water or alcohol/water mixtures were found to be stable to flocculation between 25?°C and 50?°C.