Letter to the Editor
The Role of Colloidal Stability in the Formation of Gold Sols

https://doi.org/10.1006/jcis.1993.1430Get rights and content

Abstract

The stability of gold sols, formed by the reduction of AuCl-4 with trisodium citrate, was examined as a function of reaction time using optical spectroscopy and direct force measurements performed with an atomic force microscope (AFM). The competitive adsorption of the ions and the effects of each species on the dispersion forces for the sol are examined. Analysis of the data suggests that the AuCl-4 is adsorbed preferentially at the gold/water interface but, due to its lower charge density, is not as efficient a dispersion agent as the trivalent citrate anion. The use of raw force data from the AFM to attain a qualitative understanding of colloidal phenomena is also demonstrated with this study.

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