We report that concentrated fumed silica nanosols exhibit anomalous rheology with regards to predictions based on DLVO theory. Despite a high electrokinetic potential at pH 8, fumed silica not only exhibits rheologicl behavior normally indicative of an unstable suspension but also the rheology does not have the expected dependence on ionic strength. In this study, experimental measurements and simple geometric considerations are used to clarify the influence of solids loading and the electrical double-layer on the rheological behavior of concentrated silica nanosols, and to compare their behavior with that of much larger silica microspheres.
Citation: Materials Chemistry and Physics
Pub Type: Journals
cmp slurries, colloidal silica, dynamic mobility, electrokinetics, fumed silica, nanosol, particle interactions, rheology, silica