We report a simple method of forming Au nanostructure arrays over large areas. A thin film of oligothiodendrimer-stabilised An nanoparticles was prepared via spin-coating on a solid substrate. The morphology of the adsorbed thin films is found to be markedly sensitive to the hydrophobicity of the underlying substrate. Adsorption on hydrophilic surfaces (native oxide-terminated Si(1 1 1) and mica) results in the formation of spatially correlated droplet aggregates with an average diameter of similar to 300 nm, an average height of similar to 30 nm, and an average areal density of similar to 3 x 10(8) cm(-2). On a highly hydrophobic surface (H:Si(1 1 1)), however, the dendrimer-coated particles aggregate so that the average height and diameter of the clusters are much lower (similar to 5 nm and similar to 100 nm, respectively) whereas the areal density is significantly higher (similar to 5 x 10(9) cm(-2)). Moreover, and importantly, there are key differences in the topography of the aggregates on the hydrophobic and hydrophilic surfaces. While for the hydrophilic surfaces the aggregates form droplets with an approximately hemispherical shape, on H:Si(1 1 1) the dendrimer-coated nanoparticles aggregate to form mesa-like or 'doughnut' features. (c) 2007 Elsevier B.V. All rights reserved.