Time-Dependent Strength of Colloidal Gels

S. Manley, Harvard University
Benny Davidovitch, Harvard University
Neil R. Davies, Harvard University
L. Cipelletti, Universite Montpellier II
A. E. Bailey, Harvard University
Rebecca J. Christianson, Franklin W. Olin College of Engineering
U. Gasser, University of Konstanz
V. Prasad, University of California - Santa Barbara
P. N. Segre, Harvard University
M. P. Doherty, NASA Glenn Research Center
S. Sankaran, NASA Glenn Research Center
A. L. Jankovsky, NASA Glenn Research Center
Zin Technologies, Inc.
Zin Technologies, Inc.
Zin Technologies, Inc.
Zin Technologies, Inc.
Zin Technologies, Inc.
D. A. Weitz, Harvard University

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© 2005 American Physical Society. The article appeared in Physical Review Letters, Vol. 95, Iss. 4 and may be found here.

Abstract

Colloidal silica gels are shown to stiffen with time, as demonstrated by both dynamic light scattering and bulk rheological measurements. Their elastic moduli increase as a power law with time, independent of particle volume fraction; however, static light scattering indicates that there are no large-scale structural changes. We propose that increases in local elasticity arising from bonding between neighboring colloidal particles can account for the strengthening of the network, while preserving network structure.