8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

Thu 811:10-14:00P7.77Formation of nano-scale water droplets andcharacterization of several modes of dynamicinstabilities by directly imaging in a TEMUtkur Mirsaidov, 1 Haimei Zheng, 2 and Paul Matsudaira 11 Center for Bioimaging Sciences, 14 Science Dr 4, 117543, Singapore, Singapur2 National Center for Electron Microscopy, Berkeley, United States of AmericaMuch of the interesting and important biology occurs at the interface with water. In an attemptto understand the properties of water within the few nanometers of the surface of a protein, membraneor other materials, theory and modeling have proposed often conflicting conclusions becausethere is no direct observation techniques for liquids at these scales. Here we report the ability toform 10-100 nanometer-sized droplets of water, image these droplets at room temperature in theelectron microscope, and to characterize the dynamics of the droplets as they are heated by a beamof electron. These droplets are formed by heating water in specially designed liquid cells fabricatedfrom Si 3 N 4 and isolated from the vacuum of the TEM. At the nm-scale, these dropletscontain a finite number of water molecules range of a few million water molecules. Furthermore,most of the water lies at an interface, either with the Si 3 N 4 substrate or air. Thus, most of thewater in a nanodroplet should not exhibit any properties of bulk water but more closely resemblethe properties in direct contact with a biological or any other surface. Our studies reveal severalunusual properties of nanodroplets of water including several forms of dynamic instability. First,the thin film of water breaks down into nanodroplets when energy is pumped into this film. Second,these droplets translocate on the surface of the Si 3 N 4 under beam influence of TEM. Third,we observe evidence from the trajectories of the droplets of short-range interactions because thedroplets appear attracted to each other when they move within a few nanometers of each other.Broadly speaking, this work opens up a new avenues for understanding the physics, chemistry, andbiology of nano-scale liquids at an interface with polymeric or solid materials, gases, and other liquidsby providing a method for generating nanodroplets and measuring directly through electronmicroscopy.77