Researchers demonstrated new ways to use electron microscopy to study liquids at high resolution. This new method combines different microscopy techniques. Using a beam of electrons, scientists took images of the sample as well as measured how much energy was lost as a result of the sample scattering the electrons. They used this technique to examine how nuclei in liquids and molecules vibrate at multiple length scales. This work can lead to new ways for scientists to describe liquids, the interfaces between fluids, and materials labeled with isotopes.
To better study liquids for energy applications, scientists need improvements in microscopy and imaging techniques. They need unique instruments that have greater spatial resolution. Over time, these tools will enable scientists to fine-tune materials at the atomic level. That will allow them to use these materials in more applications, like energy storage and conversion. The new approach overcomes several experimental challenges scientists face in understanding the physics of liquids. In particular, it allowed scientists to study properties of water and other liquids at a nanometer scale.
This research demonstrates a newly developed approach that can capture the vibrational properties of liquids at a very high resolution (~50 nanometers) using electron energy-loss spectroscopy (EELS) in a scanning transmission electron microscope (STEM). The combination of vibrational EELS and STEM techniques creates a unique opportunity to study water and other liquids that are not well-suited to existing vacuum-based methods. It also minimizes background noise and radiation damage to liquid samples that typically inhibit high-energy, high-resolution liquid studies.
The research was performed at the Center for Nanophase Materials Sciences at Oak Ridge National Laboratory, which is a Department of Energy Office of Science user facility. The research at UIC was supported by the National Science Foundation. Expertise with the software used for this research was provided by the Nion Company.