LAUSR

Several systems are now commercially available to analyze samples in liquid. They can be classified into two main categories. The first one corresponds to liquid cells, where the liquid is encapsulated into two thin membranes. The cell is then introduced into a Transmission Electron Microscope (TEM) operating under vacuum. Eventually, the liquid can flow or may be heated, which requires specific sample holders. If no heating or flow is required, newly designed cells can even be placed onto regular sample holders. The second category corresponds to Environmental Scanning Electron Microscopes (ESEM). When cooled down to a few degrees and when surrounded by the appropriate gas pressure, a liquid droplet can be maintained at the liquid-vapor equilibrium. In all cases, a well suited imaging mode corresponds to the collection of scattered electrons in transmission, which gives rise to a mass-thickness contrast [1].