Environmental Scanning Electron Microscopy
SEM environmental mode allows imaging of specimens that contain water, including biological samples. The SEM is operated with water vapour in the specimen chamber, and the sample is cooled using a Peltier stage. Cooling causes water vapour to condense onto the sample surface, and by balancing the amount of water that is condensed onto the specimen to that lost to the vacuum system, humidity can be maintained. By then varying the amount of water vapour in the chamber, humidity can be altered, allowing wetting and drying experiments to be conducted. Videos can be made during dynamic experiments to record the changes to specimens.
