Rheological and Electrokinetic Behavior Associated with Concentrated Nanosize Silica Hydrosols
J Y. Kim, U Paik, Vincent A. Hackley
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.