Dresden 2003 – wissenschaftliches Programm

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O: Oberflächenphysik

O 8: Teilchen und Cluster

O 8.4: Vortrag

Montag, 24. März 2003, 15:45–16:00, HSZ/02

In situ optical observation of nano-colloidal gold film deposition — •Herbert Wormeester, Martijn Brouwer, Stefan Kooij, Arend van Silfhout, and Bene Poelsema — MESA+ Research Institute, University of Twente, Enschede, The Netherlands

The deposition kinetics of the irreversible adsorption of citrate-stabilised, 13 nm diameter gold particles on APTES derivatised Si/SiO₂ surfaces was studied with single wavelength reflectometry. A well-defined flow of colloids towards the surface is realized using an impinging jet set-up. The saturation coverage after prolonged deposition depends on the ionic strength of the solution, in good agreement with DLVO theory. After an initial build-up of the jet stream, the dynamics of the deposition process is at first mass transport limited. Surface blocking effects determine the adsorption kinetics in the final stage. The whole deposition process can be completely understood within the Diffusion assisted Random Sequential Adsorption theory, which predicts a large influence of site diffusion for these small particles.