We examine the interactions between gold nanoparticles stabilized by the 4-(dimethylamino)pyridine (DMAP-AuNP) and various polyelectrolytes (PEs), both in solution and in layer-by-layer (LbL) assembled multilayer films. UV-vis spectrophotometry studies showed that the plasmon absorption band of the DMAP-AuNP in solution red-shifts and broadens in the presence of poly(sodium 4-styrenesulfonate) (PSS), poly(allylamine hydrochloride) (PAH), or poly(ethyleneimine) (PEI). This suggests that the polyanion PSS electrostatically associates with the nanoparticles, while PAH and PEI bond through the amine functionalities, despite having the same charge as the nanoparticles. In contrast, the addition of poly(diallyldimethylammonium chloride) (PDADMAC) to a DMAP-AuNP dispersion has no influence on either the peak position or shape of the absorption spectrum of the nanoparticles, indicating no interaction. PE/nanoparticle hybrid films were assembled by a single-step adsorption of the DMAP-AuNP into preassembled LbL PE multilayer films. The interactions between the DMAP-Au NP and the multilayer films were investigated by UV-vis spectrophotometry, quartz crystal microgravimetry, and surface plasmon resonance spectroscopy. These experiments revealed that PAH/PSS films have a highly uniform and dense DMAP-AuNp coverage, which is attributed to the bonds formed between the nanoparticles and PAH and PSS in the films. Additionally, the DMAP-AuNP adsorbed amount and the nanoparticle-nanoparticle interactions (and hence film optical properties) can be controlled by the number of preassembled PAH/PSS bilayers. In contrast, for PDADMAC/PSS films only a sparse and nonuniform DMAP-AuNP coating is obtained, and an irregular trend between PE bilayer number and DMAP-Au NP adsorbed amount was observed. The results obtained indicate that the combined interactions originating from PAH and PSS with DMAP-AuNP facilitate the preparation of stable nanoparticle/PE thin films with tailored optical properties. Such films may be exploited in diverse areas, including electrochemical sensing, colloidal crystals, and controlled delivery.
|Number of pages||7|
|Journal||Chemistry of Materials|
|Publication status||Published - 2005 Aug 23|
ASJC Scopus subject areas
- Chemical Engineering(all)
- Materials Chemistry