2008 NSTI Nanotechnology Conference and Trade Show - Nanotech 2008 - 11th Annual

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Clean Technology 2008

The Nanoscale Description of Solvent Diffusion to the Gold Colloids Encapsulated in Silica Sol-Gel

K. Yokoyama, T.M. Gilbert, D.D. Chen, L. Chen
The State University of New York, Geneseo College, US

Keywords:
gold colloids, silica sol-gel, diffusion

Abstract:
Various sizes of gold nano colloidal particles ranging from 5 nm to 100 nm of size were encapsulated in a silica based sol-gel, and these surfaces were exposed to a pH 1 acid solution. This enabled us to observe the process of solvent intrusion and interaction with gold colloids through colour change which was monitored by the absorption spectrum as a function of time. The rate was analyzed by a single exponential analytical function, and the maximum rate was found for gold colloid of 15 nm size. The least acid interaction and colour change was observed for the size of 60 nm. It was speculated that the surface of these gold colloids were homogeneously covered by the silica gel layer, thus avoiding direct contact of the acid with the surface of the gold colloid. The close match of the average size of the cavity with the size of the gold colloids was considered to contribute to a lack of acid penetration. This study confirmed that the nano scale dopant size affects the rate of solvent penetration into a sol-gel cavity


Nanotech 2008 Conference Program Abstract