SummaryNaturally deformed ice contains subgrains with characteristic geometries that have recently been identified in etched surfaces using high-resolution light microscopy (LM). The probable slip systems responsible for these subgrain boundary types can be determined using electron backscattered diffraction (EBSD), providing the etch features imaged with reflected LM can be retained during EBSD data acquisition in a scanning electron microscope (SEM). Retention of the etch features requires that the ice surface is stable. Depending on the pressure and temperature, sublimation of ice can occur. The equilibrium temperature for a low pressure SEM operating at 1 × 10 −6 hPa is about −112 • C and operating at higher temperatures causes sublimation. Although charging of uncoated ice samples is reduced by sublimation, important information contained in the etch features are removed as the surface sublimes. We developed a method for collecting EBSD data on stable ice surfaces in a low pressure SEM. We found that operating at temperatures of <-112 • C reduced sublimation so that the original etch surface features were retained. Charging, which occurred at low pressures (<1.5 × 10 −6 to 2.8 × 10 −5 hPa) was reduced by defocusing the beam. At very low pressures (<1.5 × 10 −6 hPa) the spatial resolution with a defocused beam at 10 kV was about 3 µm in the x-direction at −150 • C and 0.5 µm at −120 • C, because at higher temperature charging was less and only a small defocus was needed to compensate it. Angular resolution was better than 0.7 • after orientation averaging. Excellent agreement was obtained between LM etch features and EBSD mapped

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009

The search for new functional soft materials with precise and reconfigurable structures at the nano and meso-scale is a major challenge as well as objective of the current science. Patchy colloids of different shape and functionalities are considered important new building blocks of a bottom-up approach towards rational design of new soft materials largely governed by anisotropic interactions. Herein, we investigate the self-assembly, growth of hierarchical microstructures and aging dynamics of 2D nano-platelets of two different aspect ratios (Laponite ~25 and Montmorillonite ~250) which form gels with different porosity that is achieved by tuning their mixing ratios. Qualitative in situ real-space studies are carried out, including fluorescent confocal microscopy imaging of the bicontinuous gelation process or final states, which provides dynamic visualization of the self-organization. The bicontinuous gels exhibit a foam-like morphology having pores of a few micrometers in size that can be tuned by varying the mixing ratio of nanoplatelets. It is shown that this new class of clay gels has unique and tunable physical properties that will find potential applications in the development of low cost lithium ion batteries, nanocomposites and nuclear waste management.

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008

No abstract