1 - Environmental scanning electron microscopy (ESEM): principles and applications to food microstructures

This chapter introduces some basic principles of scanning electron microscopy (SEM) and its extension to environmental scanning electron microscopy (ESEM), describing why ESEM is useful for characterising materials of interest in food research. It first surveys the main techniques of imaging and microanalysis in SEM. The principles of ESEM are then described, explaining how gases can be used to mitigate electrical charging of uncoated insulating materials and contribute to the image formation process, and other ways in which gases and specimen temperature control are useful for expanding the range of available techniques to yield additional information about the structure–property relations of hard, soft and even liquid specimens. Several key application techniques will be covered, from general imaging of dry or moist, uncoated specimens through to in situ dynamic experiments.