Researchers at the University of Illinois Urbana-Champaign have made a breakthrough in visualizing nanoscale voids in filtration materials, paving the way for improved performance in various industries. The study, published in Nature Communications, combined high-powered microscopy with mathematical graph theory to map these randomly oriented empty spaces.

"We knew that if we could find a way to see them, we could then figure out how they work and ultimately improve filter membrane performance," said Falon Kalutantirige, a University of Illinois graduate student and the study's first author.

The team examined industrial filter membranes, which appear solid to the naked eye but contain nanoscale voids within "mountainous landscapes" when magnified. By integrating materials science with graph theory, they quantitatively mapped these irregular structures to understand their impact on filtration properties.

"Mapping and measuring alone will work for materials with a regular or periodic structure... But the irregularity we observed in our study pushed us to use graph theory, which gives us a mathematical way to describe this heterogeneous and messy — but practical — material," said Qian Chen, a professor of materials science and engineering at Illinois and the study's director.

The approach revealed a strong correlation between the physical and mechanical properties of the random voids and enhanced filtration performance. The researchers believe their method can be universally applied to describe and optimize the structure of many irregular materials used in everyday life and various scientific applications.

"The title of this study hints at the concept of 'beyond nothingness,' and by that, we mean that these empty, void spaces are really important when it comes to developing the best filtration membranes," Chen said.

The advancement is expected to improve the effectiveness of next-generation porous materials, including those used in water treatment, chemical processing, energy applications and drug delivery.

The research was supported by the U.S. Department of Energy, the Air Force Office of Scientific Research and the National Science Foundation.