Grassian Group Webpage

University of Iowa Dept. of Chemistry Dept. of Chemical & Biochemical Eng. NNI@UI CGRER OSTC

 

     Microscopy- SEM, TEM, and AFM

 

In the past few years, the Grassian research group has begun to extensively use different microscopy techniques to characterize particles, including nanoparticles, to follow the reaction chemistry of individual components of mineral dust aerosol and to learn more about the spatial inhomogenieties found in surface reactions of environmental interfaces.  Some of the images that we have taken using Scanning Electron Microscopy coupled to Energy Dispersive X-ray analysis (SEM/EDX) to study the chemistry of individual dust particles, transmission electron microscopy (TEM) to measure nanoparticle size distributions and atomic force microscopy (AFM) to investigate spatial inhomogenieties are shown below.

 

SEM/EDX Images

 

Heterogeneous reactions of individual particles from an authentic dust sample – China Loess – followed by SEM/EDX. The three particles labeled a, b and c are a clay particle, calcium carbonate particle and quartz particle. These show different reactivity with nitric acid (e.g. CaCO3 particles shows unique morphology changes due to the formation of deliquescent calcium nitrate), demonstrating the difference in reactivity of the components of mineral dust aerosol. These studies are being done with Dr. Alexander Laskin at Pacific Northwest National Laboratory.

 

 

 

 

 

TEM Images

 

TEM image of 5 nm particles used to investigate the health implications of commercial manufactured nanoparticles. The individual particles can be seen in this image. The scale bar on the bottom is 20 nm.

 

 

 

AFM Images


AFM Height images of MgO(100) (a) before and (b) after reaction with nitric acid.  The white spots in image (b) are  magnesium nitrate crystallite, not a continuous thin film that was proposed from spectroscopic studies.  These crystallites are on the order of 0.5 to 1 micron wide and 40 nm in height.
 

Copyright 2005 The University of Iowa Created by Jonas Baltrusaitis