Deposition kinetics of nanocolloidal gold particles

The deposition kinetics of the irreversible adsorption of citrate-stabilized, nanocolloidal gold particles on Si/SiO2 surfaces, derivatized with (aminopropyl)triethoxysilane (APTES), is investigated in situ using single wavelength optical reflectometry. A well-defined flow of colloids towards the surface is realized using a radial impinging jet cell geometry. The dynamics of the deposition process is at first mass transport limited. Surface blocking effects determine the adsorption kinetics in the final stage. The entire deposition process can be adequately described in terms of a generalized adsorption theory, which combines the effects of mass-transport and the actual adsorption onto the surface. The diffusion coefficient of the particles is calculated from the initial deposition rate. The obtained value corresponds well with data obtained from experiments described in literature and with the value calculated from the Stokes-Einstein relation.