17:15 〜 19:15
[MIS13-P05] 透過電子顕微鏡法による湿度制御環境のその場観察と地球科学への応用
キーワード：透過電子顕微鏡法、環境セル、その場観察、結晶化、湿度環境、エアロゾル
Transmission electron microscopy is one of the most useful analytical techniques in the field of earth science because it enables observation with high spatial resolution, identification of crystals by electron diffraction, elemental analysis, and so on. However, it is difficult to observe volatile or thick samples because the sample must be under a high vacuum environment and the electron beam is transmitted through the sample. In recent years, environmental cell transmission electron microscopy, in which a liquid and/or gas is sandwiched between two thin films to control the environment around the sample, has been established [1]. This technique allows the observation of samples in a solution and/or atmospheric pressure environments by transmission electron microscopy. As a result, crystallization from a solution can now be captured with higher spatial resolution than with optical microscopy, revealing the existence of various crystallization pathways [2].
On the other hand, the liquid layer in this method is often thicker, resulting in lower spatial resolution. Therefore, it is necessary to control the thickness of the liquid layer for observation with higher spatial resolution. Furthermore, to observe crystallization with higher spatial resolution, crystallization events must occur within the narrow field of view that is being observed. For observing crystallization from a solution with higher spatial resolution, we have developed a system that introduces humidity-controlled gas into a transmission electron microscope with an environmental cell to satisfy all the requirements mentioned above. By using humidity-controlled gas and deliquescence of salt, it is expected that crystallization and dissolution can be controlled at the same observation point. This system can also be used to observe the salt deliquescence phenomenon itself and the hygroscopic behavior of aerosol particles in the atmospheric environment. In this presentation, we report on the results of in situ observations of salt behavior using this system.
[1] F. M. Ross (Ed.), Liquid Cell Electron Microscopy. Cambridge University Press, 2016.
[2] M. H. Nielsen et al., Science 345, 1158, 2014.
On the other hand, the liquid layer in this method is often thicker, resulting in lower spatial resolution. Therefore, it is necessary to control the thickness of the liquid layer for observation with higher spatial resolution. Furthermore, to observe crystallization with higher spatial resolution, crystallization events must occur within the narrow field of view that is being observed. For observing crystallization from a solution with higher spatial resolution, we have developed a system that introduces humidity-controlled gas into a transmission electron microscope with an environmental cell to satisfy all the requirements mentioned above. By using humidity-controlled gas and deliquescence of salt, it is expected that crystallization and dissolution can be controlled at the same observation point. This system can also be used to observe the salt deliquescence phenomenon itself and the hygroscopic behavior of aerosol particles in the atmospheric environment. In this presentation, we report on the results of in situ observations of salt behavior using this system.
[1] F. M. Ross (Ed.), Liquid Cell Electron Microscopy. Cambridge University Press, 2016.
[2] M. H. Nielsen et al., Science 345, 1158, 2014.