Nanoparticles based nanostructured films are currently under intense investigation because their potential applications in various fields such as semiconductors, molecular electronics, photovoltaic, chemical and biological sensing and catalysis [1]. The assembly of metal nanoparticles into bi- or tri-dimensional superstructures has been reported using various kinds of electroactive linkers. Recently, the layer-by-layer growth of polyelectrolyte/gold nanoparticle films has also been reported [2]. Depending on the polyelectrolyte structure and the nanoparticles properties as well as the self-assembling conditions the final properties of the film can be modified.
In this work we describe the electrostatic LbL assembling of negatively charged gold nanoparticles (NP6: 6.4±0.6 nm and NP11: 11.0±0.7 nm) with a viologen-based cationic redox polyelectrolyte (PV). The growing of PV-NP assemblies was demonstrated from UV-visible experiments showing an increase of the NP6 or NP11 surface plasmon resonance absorption band intensity as a function of the number of layers. In addition, ellipsometric in situ studies were performed to follow the step by step growth of the PV-NP assemblies on MPS-thiolated gold surfaces. The D-y trajectories obtained at two wavelengths (546.1 and 632.8 nm) for assemblies ended either by PV or NP using different NP time adsorption (15 or 60 minutes) were fitted on the basis of different optical models. UV-visible spectra and ellipsometric results are correlated with the structure of the PV-NP assemblies.
