Lawrence Berkeley National Laboratory

We have directly observed motion of inorganic nanoparticles during fluid evaporation using a Transmission Electron Microscope. Tracking real-time diffusion of both spherical (5-15 nm) and rod-shaped (5x10 nm) gold nanocrystals in a thin-film of water-15percentglycerol reveals complex movements, such as rolling motions coupled to large-step movements and macroscopic violations of the Stokes-Einstein relation for diffusion. As drying patches form during the final stages of evaporation, particle motion is dominated by the nearby retracting liquid front.