4/6/2026 Taylor Parks
Written by Taylor Parks
Assistant Professor Lili Cai and collaborators recently published their findings on printable polymer nanocomposites for radiative cooling in the prestigious journal Nature Communications.
Daytime radiative cooling describes the use of specially designed surfaces to reflect sunlight and emit heat, reducing structure temperature without consuming energy. This is particularly relevant to large infrastructures, such as warehouses or factories, where passive heat emission could improve internal temperatures and overall energy efficiency. Most daytime radiative coolers that are currently available are manufactured as porous coatings in the form of planar films. However, these often lack durability and indiscriminately block sunlight from passing through transparent surfaces. Cai’s team has changed the field by demonstrating a method for printing radiative cooling structures using an ink that requires low particle loading—in other words, that is much more easily processed during manufacturing.
In their publication, Cai’s team debuts a new design principle that links polymer viscoelasticity to particle dispersion and optical scattering, resulting in an ink-like coating that can support paint-like, scalable manufacturing as well as 3D printing for the fabrication of architected structures.
“Our work demonstrates a new material design that enables scalable manufacturing methods,” Cai said. “We achieved record-level radiative cooling performance and mechanical robustness.”
Recent doctoral graduate Kai Zhou (PhD ME 2025) is the article’s first author. Coauthor Songtao Tang is a postdoctoral researcher in Cai’s research group alongside graduate student and coauthor Pranto Karua. Other coauthors include members of the U.S. Army Corps of Engineers Sungmin Hong, Gwendolyn Reeser, and Dr. Donald Cropek; recent MS graduate Diya Patel (MSME 2025); MechSE Professor Paul Braun, and graduate student Fukang Wu from Braun’s research group. Hong and Cropek served as the main collaborators from the Army Corps’ Construction Engineering Research Laboratory (CERL) and led the team’s field testing. Braun assisted with insightful discussion and microstructure characterization.
From a commercial standpoint, the team’s product paves the way for the development of commercial paint applications. Their work has implications for research as well—in their article, they demonstrated the capability to fabricate three-dimensional structures using their radiative cooling polymer.
“This can be used not only as a coating or paint, but also as its own structure,” Cai said, noting that her team demonstrated the first radiative cooling structure that still admits diffused daylight for illumination—in other words, reducing both cooling and lighting demand. The team also successfully printed a fibrous mask among other items including a channeled slab and cylindrical tube. “We can develop three-dimensional thermal structures using additive manufacturing methods.”
In ongoing work, the team intends to develop more complex, working prototypes of radiative structures. “We have some very exciting projects centered around this fabrication capability,” Cai said.