Surface Charge Effects Involved in the Control of Stability of Sols Comprising Uniform Cholesterol Particles

Abstract

The reported is a method for the preparation of stable dispersions of narrowly dispersed cholesterol crystals, which may provide an excellent model for the aggregation studies thereof. The effects of experimental parameters that include concentration, pH, ionic strength, temperature, and aging on the resulting morphologies are acknowledged. Regardless of the cause of destabilization, the multilayered aggregates of cholesterol particles are formed by “face-to-face” stacking of the original platelets, as promoted by higher surface charge density on particle sides comparing to their faces. In accordance with the crucial involvement of surface charge effects in stabilization of cholesterol dispersions produced hereby, aggregation of the original particles becomes enhanced at increased salt contents and at pH conditions that correspond to the isoelectric point of the dispersed particles.

Keywords:

• Cholesterol
• Sol
• Surface charge
• Uniform particles
• Zeta potential

ACKNOWLEDGMENTS

This work was done during the author's appointment with the Center for Advanced Materials Processing, Clarkson University, Potsdam, NY 13699, USA.

This research was supported by the NSF grant DMR-0509104.