Environmental scanning electron microscopy (ESEM) is a powerful imaging technique that involves the use of a scanning electron microscope (SEM) to examine samples under near-native environmental conditions. Unlike traditional SEM, which requires samples to be dehydrated and placed in a vacuum, ESEM allows observation of samples in their natural hydrated state. It enables scientists to study biological, physical, and chemical processes in various environments, including excess humidity, gas, or liquid.
In ESEM, a high-energy electron beam is focused on the sample, causing the emission of secondary electrons, backscattered electrons, and characteristic X-rays. These signals are then detected and translated into images by a specialized detector. The microscope also includes a pressure control system to ensure that the sample's environment remains stable throughout the imaging process.
The advantage of ESEM is that it provides detailed information on the surface morphology and topography of samples, allowing for the observation of dynamic processes such as growth, movement, and reaction. It is particularly valuable for studying hydrated or sensitive samples that cannot withstand the harsh conditions of traditional SEM.
Environmental scanning electron microscopy has numerous applications in various fields, including materials science, biology, geology, and environmental science. It has been used to study the structure and behavior of cells, nanomaterials, fossils, and corrosion processes, among others. ESEM's ability to examine samples in near-natural conditions makes it a valuable tool in understanding and characterizing complex systems and processes occurring in different environments.
