Interaction of liquids with nanoporous cluster assembled au films

We report a spectroscopic ellipsometry investigation of the interaction of nanoporous cluster-assembled Au films with pure ethanol in a liquid environment. The Au films were first characterized in atmosphere in terms of the mean size of the constituent clusters and their porosity. Upon immersion in liquid, a clear correlation between the relative density of the films and the corresponding fraction of pores that could be filled by ethanol molecules was observed. Low-density porous Au structures exhibit abundant open pores, accessible by molecules from the ambient, whereas for higher-density structures the fraction of accessible pores sharply drops. We found evidence that the pore accessibility in cluster-assembled films with pore dimension in the sub-10 nm range is strongly dependent on fine morphological details of the solid scaffold.