Soft matter expert Brun wins APS Award for “creative and groundbreaking” research

Written by
Stephanie Pappas, for the Office of Engineering Communications
Oct. 11, 2022

Pierre-Thomas Brun, an expert in soft-matter engineering, has been awarded an early career award by the American Physical Society (APS).

The Early Career Award for Soft Matter Research goes to one recipient each year for contributions to soft matter research. Brun, an assistant professor of chemical and biological engineering, will be recognized at an upcoming APS meeting for “creative and groundbreaking contributions to make soft functional materials using mechanical and hydrodynamic instabilities, elasticity and flow, from bubble casting for soft robotics to pendant drops coated on the underside of a substrate.”

stages of an inflatable, soft-robotic arm reaching for and grasping a ball
Brun devised a way to control elastic polymers for inflatable structures that rely on small amounts of injected air to reach for and grasp objects with sensitivity and precision. Courtesy Pierre-Thomas Brun.

Brun’s work often draws inspiration from patterns found in nature to design new fabrication technologies. In 2021, he and his team published a paper in the journal Nature describing “bubble casting,” a new way to make soft robots. The technique involves injecting bubbles into a liquid polymer, allowing the polymer to cure, and then using air to move and bend the resulting soft structure. Researchers can control how the soft robot bends by varying the shape of the mold, the polymer’s cure time, and the thickness of the polymer.

In one recent study, Brun and his team discovered a way to grow hair-like spindles by spinning a liquid elastic on a disc, not unlike the way sugar is spun into cotton candy, with applications for assembling complex materials. Another study showed that the same physics that breaks a thread of water falling from a kitchen faucet can lead to the assembly of two-dimensional arrays of drops, with advanced mechanical and acoustic properties.

Other projects involve new ways to fabricate soft materials. Earlier this year, Brun led research developing a method of printing pixelated sheets of curable elastic polymers, which can’t be printed with conventional 3D printers. The method uses the natural physics of fluid flow, such as capillary action, to herd the polymers into the desired spaces. The resulting sheets can be designed pixel-by-pixel for applications in anything from soft robotics to medical device development.

The award provides $5,000 and the cost of travel to the APS March meeting. It has been given since 2015 and is awarded to researchers with fewer than 12 years of activity after their Ph.D.

Brun earned his M.S. in chemical engineering at Cambridge University in 2009 and his Ph.D. in mechanics at the Université Pierre-et-Marie-Curie in 2012. Before joining the faculty at Princeton, he was a postdoctoral fellow at the École Polytechnique Fédérale de Lausanne in Switzerland and the Massachusetts Institute of Technology. He is a 2021 recipient of a National Science Foundation CAREER award.