1. Quasi‐Newtonian Environmental Scanning Electron Microscopy (QN‐ESEM) for Monitoring Material Dynamics in High‐Pressure Gaseous Environments
- Author
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Kyle L. Wilke, Jinlong Zhu, Evelyn N. Wang, Lenan Zhang, Xiangyu Li, and Lynford L. Goddard
- Subjects
Materials science ,General Chemical Engineering ,environmental scanning electron microscopy ,General Physics and Astronomy ,Medicine (miscellaneous) ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Biochemistry, Genetics and Molecular Biology (miscellaneous) ,Signal ,Secondary electrons ,Nanomaterials ,Newtonian ,scattering force ,General Materials Science ,Time domain ,lcsh:Science ,high‐pressure gaseous chamber ,Environmental scanning electron microscope ,Scattering ,Communication ,material dynamics ,Condensation ,Resolution (electron density) ,General Engineering ,mechanical work ,021001 nanoscience & nanotechnology ,Communications ,0104 chemical sciences ,Chemical physics ,lcsh:Q ,0210 nano-technology - Abstract
Environmental scanning electron microscopy (ESEM) is a powerful technique that enables imaging of diverse specimens (e.g., biomaterials, chemical materials, nanomaterials) in a hydrated or native state while simultaneously maintaining micro‐to‐nanoscale resolution. However, it is difficult to achieve high signal‐to‐noise and artifact‐free secondary electron images in a high‐pressure gaseous environment due to the intensive electron‐gas collisions. In addition, nanotextured substrates can mask the signal from a weakly scattering sample. These drawbacks limit the study of material dynamics under extreme conditions and correspondingly our understanding in many fields. In this work, an imaging framework called Quasi‐Newtonian ESEM is proposed, which introduces the concepts of quasi‐force and quasi‐work by referencing the scattering force in light–matter interactions, to break these barriers without any hardware changes. It is shown that quasi‐force is a more fundamental quantity that has a more significant connection with the sample morphology than intensity in the strongly scattering regime. Experimental and theoretical studies on the dynamics of droplet condensation in a high‐pressure environment (up to 2500 Pa) successfully demonstrate the effectiveness and robustness of the framework and that the overwhelmed signal of interest in ESEM images can be reconstructed through information stored in the time domain, i.e., frames captured at different moments., This work introduces an electron imaging framework called quasi‐Newtonian environmental scanning electron microscopy (ESEM) that outperforms conventional ESEM in characterizing materials dynamics in high‐pressure gaseous environments.
- Published
- 2020