New strategy for preparing thin gold films on modified glass surfaces by electroless deposition

This paper describes a new strategy for fabricating continuous gold films based on the self-assembly of the gold colloid monolayer on a poly(diallyldimethylammonium chloride)-modified glass slide, followed by electroless plating. Hydroxylamine-mediated reduction was proven as an excellent route to enlargement of immobilized nanoparticles on polymer-coated glass substrates in comparison to formaldehyde-mediated reduction. Au colloidal surface-catalyzed reduction of Au3+ by hydroxylamine exhibited very fast kinetics as monitored and confirmed by UV-vis spectroscopy in real time. The nanoscale morphology of the gold film was dependent on the initial coverage of gold nanoparticles and thermal annealing. Atomic force micrographs further revealed that enlarged particles were neither spherical nor cyclindrical, but highly complex in shape. The gold film thickness and its corresponding surface roughness could be easily controlled by setting the electroless deposition time. X-ray diffraction certified uniformity of deposits with the Au(1 11) crystallographic structure as the predominant one. No organic contamination during the course of electroless plating was observed as confirmed by both X-ray photoelectron spectroscopy and contact angle measurements. The stable and continuous gold films were used as electrodes for electrochemical experiments.