image: Liheng Cai, an associate professor at the University of Virginia School of Engineering and Applied Science, is the 2026 John H. Dillon Medal winner.
Credit: University of Virginia
The American Physical Society has awarded its 2026 John H. Dillon Medal to Liheng Cai at the University of Virginia School of Engineering and Applied Science.
Cai is an associate professor in the departments of Materials Science and Engineering and Chemical Engineering whose research has twice challenged long-accepted “rules” of how polymers are supposed to behave. His discoveries offer enormous promise for designing better, safer materials for applications in health care and sustainability.
“This is among the most highly prized awards in polymer research,” said dean of UVA Engineering Jennifer West. “It’s truly a mark of distinction for Liheng and the research program he has built here, and a testament to the significance of his groundbreaking work.”
The medal recognizes Cai’s work for “pioneering the understanding and applications of architecturally complex polymers and networks using experiments and theory,” the society announced on Nov. 5.
“Grateful,” said Cai of how he felt upon hearing the news.
“You only get this honor with tremendous support, from advisors and mentors, your school and leadership, the research community, funders, and most of all, grad students and postdocs who do the work in the lab,” Cai said. “I’ve been blessed with all of the above and I’m incredibly honored and humbled that our lab’s work has been recognized in this way.”
The Dillon Medal was established in 1983 by the American Physical Society and its Division of Polymer Physics to recognize an early- to mid-career researcher for “outstanding accomplishment and unusual promise” in polymer physics.
Going back to his Ph.D. studies at the University of North Carolina, where he was trained in theoretical polymer physics with physicist Michael Rubinstein, Cai has grappled with the fundamental challenge of these big, versatile molecules: How to make new materials without having to trade off one desirable trait for another.
As Cai’s career progressed through two postdoctoral appointments, at UNC and at Harvard University with David Weitz, another physicist, he was given freedom to explore experimentation as a path to discovery — though he remained rooted in the fundamental science of polymers.
“Our lab’s philosophy is to identify and solve problems of both fundamental importance and practical value,” Cai said. “This is often accomplished by working closely with experts from various fields.”
Since establishing his own lab at UVA in 2018, Cai’s quest has led to two consequential findings.
The first challenged the prevailing understanding of associative polymers, a class of materials with unique self-healing and flow properties. Cai’s team offered a new theory to explain their behavior that shifts thinking about how to engineer these materials with optimized properties.
Then his team discovered how to make “foldable bottlebrush polymers and networks,” solving a conundrum that has stumped scientists since Charles Goodyear invented vulcanized rubber nearly 200 years ago. They figured out how to stiffen a material without sacrificing its ability to stretch — traits needed for high-performance polymeric materials and compatibility with biological tissue. That paper appeared on the cover of Science Advances.
The Dillon Medal also recognizes how Cai’s team has applied these findings to develop drug delivery systems and 3D printing of soft materials, as well as how they’ve translated their knowledge in polymer physics to advance biomaterials for voxel bioprinting.
Over his career, Cai’s numerous awards include the U.S. Presidential Early Career Award for Scientists and Engineers, National Science Foundation CAREER Award, National Institutes of Health Maximizing Investigators’ Research Award, the American Chemical Society Petroleum Research Fund Doctoral New Investigator Award and ACS Polymeric Materials: Science and Engineering Early Investigator Award, and UVA’s Research Excellence Award. He has also been recognized as a Royal Society of Chemistry Soft Matter Emerging Investigator and an ACS Polymers Au Rising Star.
“None of this is possible without my students and postdocs,” Cai said. “They are the driving force to make those discoveries. They are never afraid of trying new ideas. Yes, we can always try new ideas, but how do we pick the right ones?”
Cai will receive the Dillon Medal at the APS Global Physics Summit in Denver next March.