Stabilization of aqueous clay suspensions with AOT vesicular solutions

Abstract

Greatly extended stability of clay aqueous suspensions of particles of size about 10–100 nm is achieved by the incorporation of Aerosol OT (AOT) vesicular solutions. Direct images of the interactions between clay particles with AOT vesicles and liposomes in aqueous suspensions, with and without added NaCl, have been obtained for the first time by artifact free (no drying and no staining) cryogenic transmission electron microscopy (cryo-TEM). Combined centrifugation and cryo-TEM results indicate that the heightened stability of the clay-AOT suspension is due mainly to strictly limited mobility and separation of clay particle aggregates in the presence of large multi-bilayers, and to a lesser extent by the encapsulation of clay particles. Greatly reduced rigidity of bilayers and shrinking of vesicles, with the added NaCl, lead to a lowered effect of stabilization with AOT vesicular solutions.