title: Effects of particle softness on shear thickening of microgel suspensions.
abstract: A series of microgel particles composed of a polystyrene (PS) core and a 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 parameters. According to the obtained results, the softness parameter can provide an estimate for the shear thickening behavior of microgel suspensions, at least semi-quantitatively.
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Joint Laboratory of Polymer Science and Materials, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, CAS, Beijing 100190, China. c.c.han@iccas.ac.cn.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Zhou
authors.forename: Javoris V
authors.initials: JV
authors.lastname: Hollingsworth
authors.forename: Song
authors.initials: S
authors.lastname: Hong
authors.forename: Guangmin
authors.initials: G
authors.lastname: Wei
authors.forename: Yu
authors.initials: Y
authors.lastname: Shi
authors.forename: Xi
authors.initials: X
authors.lastname: Lu
authors.forename: He
authors.initials: H
authors.lastname: Cheng
authors.forename: Charles C
authors.initials: CC
authors.lastname: Han