A team of chemical engineers from the University of Illinois Urbana-Champaign collaborated with Argonne National Laboratory, Johns Hopkins University and the University of Ottawa to develop a new metric called a "correlation ratio" to connect larger-scale observations of soft materials failing to what happens at the microscale level. They used rheo-X-ray photon correlation spectroscopy (Rheo-XPCS) to study the flow-dependent structure-property relationships of soft materials in real-time, according to a recent press release.
Rheo-XPCS is one of the few techniques that allow researchers to perform X-ray analysis of a material as it is being deformed, while simultaneously measuring it using rheometers – devices that measure stress and strain – directly in line with an X-ray beam, the researchers said.
“From a materials science perspective, we have not been able to distinguish when a material changes from behaving like a solid to a liquid at the microstructural scale,” says Illinois chemical and biomolecular engineering professor Simon Rogers, who led the project. “The Rheo-XPCS at Argonne National Lab gives us an unprecedented peek at the microscale behavior of soft materials yielding to stress.”
The team hopes their research will allow future researchers to design new soft materials by tweaking various microscale parameters to obtain a desired macroscale property. “We’re not quite there yet, but we have shown a clearly defined mathematical correlation between the micro- and macroscale,” says Gavin Donley, the first author of the study and former Illinois graduate student now at Georgetown University.
