Priestley, the Pomeroy and Betty Perry Smith Professor of Chemical and Biological Engineering and dean of the Graduate School, has discovered many phenomena within the study of polymers and soft matter, particularly thin films, colloids and the intricately layered class of materials known as nanocomposites — materials that are important to electronics, cosmetics, medicines and other commercial products.

Out of more than 150 APS Fellows elected this year, Priestley was one of only three sponsored by the Division of Polymer Physics, underscoring the impacts of his work in this field. His election was announced by the organization on Oct. 19.

In one key area of research, Priestley has revealed deep truths about the glass transition, a fundamental material property that has puzzled scientists for decades. The glass transition is a kind of threshold that exists in all polymeric materials. Above it, materials are rubbery and flexible; below it, rigid and glassy. Each material has its own glass transition temperature, and as materials interact in nanoscopic, complex combinations, the effects become extremely complicated and hard to manipulate. Rigid strands of one material might trap just a few molecules of a more flexible material to combine into something that shares the bulk properties of both. But that trap is tiny. You could fit 10,000 of them across the width of an eyelash. Priestley’s work has uncovered key insights into how the glass transition changes in such confined spaces, and his research group has developed methods to tune that property for a range of technological applications.

All of that deep work has led to some deceptively simple technologies that promise to make an impact on global health and the environment. For example, in 2021 he and postdoctoral researcher Xiaohui Xu launched AquaPao, a company that is commercializing an affordable, portable water-purification device that draws directly on a membrane developed in Priestley’s laboratory. The device soaks up polluted water, say, from a lake or river. When set in the sun, it releases clean water. The contaminants remain trapped in the device’s sponge-like gel. Recent versions are efficient enough to supply daily clean water in many parts of the world.

Preistley has co-founded three other companies, and he is the co-inventor of more than 10 patent-pending technologies. He has received numerous previous awards, including the 2020 Dillon Medal from APS, which recognizes outstanding research by early-career polymer scientists, and the 2023 Carl S. Marvel Award for Creative Polymer Chemistry from the American Chemical Society. He was named to The Root 100 list of most influential African Americans in 2014.

In 2022, Priestley became Princeton’s 18^th dean of the Graduate School. Previously, he served as Princeton’s vice dean for innovation between 2020 and 2022. He is co-director of the National Science Foundation Innovation Corps Northeast Hub, a consortium designed to foster innovation at Princeton and other regional universities. Priestley got his bachelor’s degree in chemical engineering at Texas Tech University in 2003 and his doctorate at Northwestern University in 2008, where he studied nanoscale physical constraints on polymers. Before joining the Princeton faculty in 2009, Priestley was a postdoctoral fellow at Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris, in France.