A transmission electron microscopy study of hexagonal ice

Abstract

The morphologies of fast-frozen, thin-film samples of pure and dilute solutions of salts and surfactants in hexagonal ice are investigated with transmission electron microscopy. The cold-stage microscopy technique is described briefly and limitations imposed by the equipment and the sample itself are discussed. Ice grains, grain boundaries, dislocations, and stacking faults are imaged before radiolysis from the electron beam can alter their structures. The technique shows that screw dislocations in the ice basal plane are common, in accord with observations from X-ray topography and etch-replication microscopy. It also makes visible nonbasal dislocations in hexagonal ice, including dislocations in first prismatic planes, nonprismatic dislocation loops, and stacking faults on first pyramidal planes; heretofore, these defects have not been confirmed experimentally. Implications of the work for cold-stage microscopy of microstructured fluids are mentioned.