Shear induced gelation of colloidal dispersions
作者:
B. Cabane,
K. Wong,
P. Lindner,
F. Lafuma,
期刊:
Journal of Rheology
(AIP Available online 1997)
卷期:
Volume 41,
issue 3
页码: 531-547
ISSN:0148-6055
年代: 1997
DOI:10.1122/1.550874
出版商: The Society of Rheology
关键词: Gelation, shear-induced;Colloidal suspension;Dispersion
数据来源: AIP
摘要:
Nanometric silica particles, dispersed in water, have been bridged into long necklaces by adsorbing macromolecules of poly(ethylene oxide). At high coverage of particles by macromolecules the necklaces repel each other and the dispersions are homogeneous solutions; at low coverage the necklaces bind to each other and a concentrated phase separates from excess water. It is reported here that shear induced gelation and shear induced flocculation are observed near the boundary of the phase separation region. The structures of these dispersions under shear have been observed through small angle neutron scattering. It has been found that, above a critical shear rate, the necklaces connect to each other to form threadlike objects which align along the velocity. At higher shear these objects associate sideways to form three-dimensional flocs.
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