Formation of close-packed nanoparticle chains.

The self-assembly of CoPt(3) particles (diameter 6 nm) into low-dimensional ordered arrays results from phase separation in a hexane solution containing nanoparticles, hexadecylamine, and water. The evaporation of hexane from the thin film of solution initiates the formation of a water layer on the solid substrate. Subsequent dewetting of this water layer leads to the formation of water droplets. The nanoparticles follow the motion of the contact line of the dewetting water layer and thus assemble into ordered arrays at the periphery of the water droplets.