writer：Zhi Zhou; Javoris Hollingsworth; Song Hong; Guangmin Wei; He Cheng; Charles C. Han
keywords：shear thickening, softness parameter
source：期刊
specific source：Soft Matter, accepted
Issue time：2014年
A series of microgel particles composed of a polystyrene (PS) core and thermo-sensitive poly (N-isopropylacrylamide) (PNIPAM) shell with different shell thicknesses were investigated to elucidate the effect of microgel softness on its shear thickening behavior. Since the softness of the microgels increases with decreasing temperature through the volume phase transition effect of PNIPAM shell, the measured softness parameter, n, which is derived from the Zwanzig-Mountain equation, was used to measure and describe the combined influences of temperature and shell thickness. Confocal microscopy is used to investigate the interaction potential between microgel particles with different softness parameter. According to our results, the softness parameter is able to estimate the shear thickening behavior of microgel suspensions at least semi-quantitatively.