Paradox of Stability of Nanoparticles at Very Low Ionic Strength

TitleParadox of Stability of Nanoparticles at Very Low Ionic Strength
Publication TypeJournal Article
Year of Publication2012
AuthorsLin S, Wiesner MR
JournalLangmuir
Volume28
Issue30
Pagination11032 - 11041
Date Published07/2012
ISSN1520-5827
Abstract

The scaling of electrical double layer interaction energy from a plate-plate system to a sphere-plate system was reexamined, and it was found that accurate scaling without resorting to the Derjaguin approximation theoretically predicts the destabilization of nanoparticles in water depleted of added electrolyte and, consequentially, a maximum stability at a moderate ionic strength. This theoretical feature re-emphasizes the dual-role nature of added electrolyte that was supported by experimental results of direct surface force measurement but not by those of colloidal stability of nanoparticle deposition/aggregation. Inconsistences between the theoretical prediction and the experimental observation and between experimental observations in different systems were discussed. Possible reasons leading to the inconsistences were explored, including the effect of curvature, the contribution from counterions, the mode of interaction, and the applicability of an equilibrium model to describe the colloidal interaction of a nanoparticle suspension.

DOI10.1021/la3016589
Short TitleLangmuir