Patterns of gold nanoparticles formed at the air/water interface: effects of capping agents.

Gold nanoparticles stabilized with different capping agents were synthesized in a two-phase liquid-liquid system and found to self-assemble into various patterns at the air/water interface. The shapes of the patterns are closely related to the molecule structures of the capping agents. Systems with mixed capping agents were also investigated, and honeycomb patterns can be obtained in this way. T-shape and H-shape patterns were also observed. A possible mechanism based on Marangoni-Benard convection in evaporating droplets is proposed.