A two-dimensional network of Au nanoclusters on water surface: example of facile control of nanospace

We report isotherm and Brewster Angle Microscopy (BAM) studies on mixed monolayers of Stearic Acid (StA) and Dodecanethiol-capped gold nanoparticles (AuNPs) (10% by weight) at the air-water interface. The surface pressure-specific molecular area isotherm for the mixed monolayer shows small hysteresis as well as a lowering of the slope change in going from L2-L2' and L2'-S phases, indicating lesser number of monolayer phases for the mixed film relative to a pristine StA monolayer. The BAM study shows formation of a two-dimensional, stable, reproducible, and extensive network of nanoparticle clusters with near-circular pores, in the 5-20 mN/m surface pressure range. This assembly of nanospaces has a pore area peak at approximately 75 microm2, width approximately 120 microm2 and can be disassembled and reassembled simply by changing the surface pressure.