Breakthrough 3D-printed material revolutionizes soft robotics and biomedical devices

Penn State researchers have developed a new 3D-printed material that aims to advance soft robotics, skin-integrated electronics and biomedical devices. The material is soft, stretchable and self-assembles, allowing it to overcome many of the limitations of previous fabrication methods, such as lower conductivity and device failure. According to Tao Zhou, assistant professor at Penn State, the challenge of developing highly conductive, stretchable conductors has been going on for nearly a decade. While liquid metal-based conductors offered a solution, they required secondary activation methods — such as stretching or laser activation — that complicated fabrication and risked device failure.

Zhou explained that their method eliminates the need for secondary activation to achieve conductivity. The innovative approach combines liquid metal, a conductive polymer blend called PEDOT:PSS, and hydrophilic polyurethane. Once printed and heated, liquid metal particles in the bottom layer of the material self-assemble into a conductive path, while the top layer oxidizes in an oxygen-rich environment, creating an insulated surface. This structure ensures efficient data transmission to sensors—such as those used to record muscle activity and detect stress—while preventing signal leaks that could compromise data accuracy.

“This material innovation enables self-installation, which results in high conductivity without secondary activation,” Zhou added. The material’s 3D printing capability also simplifies the fabrication of wearable devices. The research team is exploring various potential applications, with a focus on assistive technology for people with disabilities.

The research, funded by the National Taipei University of Technology and Penn State Collaborative Seed Grant Program, included contributions from doctoral students Salahuddin Ahmed, Marzia Momin, Jiashu Ren and Hyunjin Lee.