Deliquescence Investigated by Environmental Transmission Electron Microscopy
Although the deliquescence relative humidities of particles such as sodium chloride or ammonium sulfate are well known when their diameters are larger than 100 nm, there have been few studies on the deliquescence of particles having diameters between 1 and 100 nm, which are abundant in the troposphere. These previous studies do, however, show different behaviors of nanoparticles as they interact with water vapor. Environmental transmission electron microscopy (ETEM) allows high resolution, in-situ observation of nanoparticles as relative humidity is cycled in an environmental cell located in the electron microscope column. In order to utilize ETEM to study deliquescence of nanoparticles, the conditions the particles experience under the electron beam need to be determined. We have used a variety of sub-micron salt particles to determine water vapor pressure and particle temperature in the environmental cell of the ETEM. With this knowledge, we plan to extend the capabilities of ETEM to study phase changes of atmospherically relevant nanoparticles.
Wise, M. E.; Biskos, G.; Martin, S. T.; and Buseck, P. R., "Deliquescence Investigated by Environmental Transmission Electron Microscopy" (2004). Faculty Research. 78.