Researchers at Penn State University have revealed a 3D-printed material that promises to transform wearable devices
This new material, shown in their recent publication in Advanced Materials, combines softness and stretchability with high conductivity, overcoming key limitations of existing fabrication methods.
Led by corresponding author Tao Zhou, assistant professor at Penn State’s College of Engineering, the team addressed longstanding challenges in achieving both flexibility and electrical conductivity in soft materials. “People have been developing soft and stretchable conductors for almost a decade, but the conductivity is not usually very high,” noted Zhou. Traditional approaches often rely on liquid metal-based conductors, which require complex secondary activation processes that can compromise device reliability.
Flexibility and electrical conductivity in soft materials
The new approach developed by Zhou and his team eliminates the need for secondary activation. By combining liquid metal with a conductive polymer mixture known as PEDOT and hydrophilic polyurethane, the researchers created a material capable of self-assembling into a conductive pathway upon printing and heating. This self-assembly process results in a highly conductive bottom layer, crucial for transmitting signals such as muscle activity and strain sensing in wearable sensors.
The top layer of the material naturally oxidizes upon exposure to oxygen, forming an insulated barrier that prevents signal leakage. This dual-layer structure not only enhances the accuracy of data collection but also simplifies the fabrication process, making it easier to produce wearable devices through 3D printing.
“Our method does not require any secondary activation to make the material conductive,” explained Zhou. “The material can self-assemble to make its bottom surface be very conductive and its top surface self-insulated.”
The next generation of wearable technology
With the ability to fabricate intricate designs through 3D printing, the material holds promise for applications in assistive technologies for individuals with disabilities, where precise and reliable sensor data are crucial.
The study’s co-authors, including doctoral students Salahuddin Ahmed, Marzia Momin, Jiashu Ren from the Engineering Science and Mechanics Department, and Hyunjin Lee from the Biomedical Engineering Department at Penn State, emphasise the collaborative effort that made this breakthrough possible.
Funding for this research was provided by the National Taipei University of Technology-Penn State Collaborative Seed Grant Program, showing the global collaboration driving innovation in materials science and biomedical engineering.
