title: Effect of adsorbed poly(ethylene glycol) on the gelation evolution of Laponite suspensions: aging time-polymer concentration superposition.
abstract: The effects of the concentration of polyethylene glycol (PEG) and NaCl on the gelation kinetics of aqueous Laponite suspensions were investigated. The PEG concentration c(p) was increased from 0.063 wt.% to 1.0 wt.%, and the NaCl concentration c(s) was increased from 3.0 mM to 5.0 mM. The gelation process was monitored with the small amplitude oscillatory shear (SAOS) rheology. At each NaCl concentration, the time curves of storage and loss moduli G' and G" at different PEG concentrations were shifted horizontally to construct a master curve. Master curves for different NaCl concentrations were shifted further into a main master curve. The results were understood in terms of an increase in steric repulsion with increasing c(p). A model based on the theory of interaction-limited coagulation was proposed to describe the dependence of the shift factor on the PEG concentration, taking into account of the interactions between particles. The quantitative description of the observed results has been achieved with this model.
authors.affiliation: Research Institute of Materials Science and State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China.
authors.forename: Weixiang
authors.initials: W
authors.lastname: Sun
authors.forename: Yanrui
authors.initials: Y
authors.lastname: Yang
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.forename: Haohao
authors.initials: H
authors.lastname: Huang
authors.forename: Xinxing
authors.initials: X
authors.lastname: Liu
authors.forename: Zhen
authors.initials: Z
authors.lastname: Tong
mesh_terms: D000327:Adsorption; D005782:Gels / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D012212:Rheology; D017640:Silicates / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry; D013535:Suspensions
chemical_list: D005782:Gels; D017640:Silicates; D013535:Suspensions; D011092:Polyethylene Glycols; D012965:Sodium Chloride; C524813:laponite