Because SPM can provide real-time, in situ images not only of topography but also of different frictional, adhesive, and viscoelastic properties, it is uniquely useful for the study of organic molecules, molecular films, or living organisms that might be difficult to identify or preserve using other techniques. Mineral dissolution and growth SPM is often used to monitor surface microtopography during mineral dissolution and growth. Proposed reaction mechanisms can be constrained and quantified through observation of growth or dissolution spirals and rates of step motion. The image is 600 nm on a side. Note the large changes in step position over time and the time-dependent increase in size of etch pits.
All images are in false color.
The growth and dissolution mechanisms of clay minerals, which can dominate the reactive mineral surface area in many hydrogeologic settings, have sometimes been controversial. SPM provides particle shape and microtopographic information that helps constrain the growth mechanisms in some cases. At the University of Colorado, Boulder, Kathy Nagy is using SPM to observe the growth modes of clay minerals. Processes that occur at the atomic scale can influence the environment at the global scale. The dissolution of certain feldspars plays a part in controlling the CO 2 content of the atmosphere over long periods.