Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/4647

 Title: Effect of silica colloids on the rheology of viscoelastic gels formed by the surfactant cetyl trimethylammonium tosylate Authors: Bandyopadhyay, RanjiniSood, A.K. Issue Date: 2005 Publisher: Elsevier B.V. Citation: Journal of Colloid and Interface Science, 2005, Vol.283, p585–591 Abstract: The effects of the addition of sub-micrometer sized colloidal silica spheres on the linear and nonlinear rheology of semi-dilute solutions of a viscoelastic gel are studied. For a 1.4 wt.% solution of the surfactant CTAT, a peak in the zero shear rate viscosity $\eta_{\circ}$ is observed at approximately equal weight percents of silica and CTAT. This peak shifts to lower silica concentrations on increasing either the CTAT concentration or the surface charge on silica and disappears when the CTAT concentration is increased to 2.6wt%. The increases in $\eta_{\circ}$ and the high frequency plateau modulus G$_{\circ}$ on the introduction of SiO$_{2}$ are explained by considering the increasingly entangled wormlike micelles that are formed due to the enhanced screening of the electrostatic interactions. The observed decrease in the values of G$_{\circ}$ and $\eta_{\circ}$ at higher concentrations of silica particles is explained in terms of the formation of surfactant bilayers due to the adsorption of the positively charged cetyl trimethylammonium to the negatively charged silica. Description: Restricted Access. URI: http://hdl.handle.net/2289/4647 ISSN: 0021-97971095-7103 (Online) Alternative Location: http://arxiv.org/abs/cond-mat/0409435 Copyright: 2005 Elsevier B.V. Appears in Collections: Research Papers (SCM)

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