title: Formation of stable Ag-nanoparticle aggregates induced by dithiol cross-linking.
abstract: Aggregation of thiol-stabilized silver nanoparticles induced by 1,6-hexane dithiol was studied in situ by dynamic light scattering. The aggregates were observed to reach a finite size in the 100-200 nm range depending on the applied conditions. Growth kinetics were shown to be linked to the dynamics of the thiol-exchange reaction. A model for the aggregation process was developed on the basis of a simple diffusion-kinetic approach assuming an elementary kinetic reaction at the surfaces and a spherical diffusion field surrounding the aggregates. The rate constant for the thiol exchange reaction was found to vary between 0.6 and 4.0 x 10(-4) s(-1), and the activation energy was 46 +/- 10 kJ mol(-1).
authors.affiliation: Laboratory of Physical Chemistry and Electrochemistry, Helsinki University of Technology, P.O. Box 6100, FIN-02015 HUT, Finland.
authors.forename: Päivi
authors.initials: P
authors.lastname: Ahonen
authors.forename: Timo
authors.initials: T
authors.lastname: Laaksonen
authors.forename: Antti
authors.initials: A
authors.lastname: Nykänen
authors.forename: Janne
authors.initials: J
authors.lastname: Ruokolainen
authors.forename: Kyösti
authors.initials: K
authors.lastname: Kontturi