Researchers from Tianjin University have developed a rapid and low-cost method for printing high-performance electronic circuits directly onto complex three-dimensional surfaces — a breakthrough that could accelerate the development of robotic "electronic skin" and next-generation wearable devices.

The technology allows electronic circuits to tightly adhere to irregular shapes such as robotic arms, airfoils and even fingers, marking a major advance in flexible electronics, a field focused on creating devices that can bend and conform to surfaces while maintaining stable performance.

Jiang Chengjie, the lead researcher, said manufacturing high-performance circuits on non-planar surfaces has long been a major challenge. Poor adhesion and limited control over circuit accuracy often cause breakage or signal instability, restricting innovation in both device design and functionality.

To address the challenges, the research team innovatively adopted commercially available thermoplastic films that shrink upon heating and can tightly wrap around objects of arbitrary shape. However, this also revealed that common metal conductors tend to break when the film contracts due to their insufficient ductility.

To tackle this problem, the research team developed a semiliquid metal material with high electrical conductivity and good fluidity, and utilized self-developed printing technology to "draw" the circuit onto the flat film.

Pre-calculation of deformation through simulation technology enables flat circuits to quickly conform to 3D surfaces as pre-designed after treatment with warm water or hot air at around 70 C. The entire process takes only five seconds, and the circuits exhibit excellent mechanical durability. Experiments have shown their electrical conductivity remains stable even after 5,000 bends or twists. The technology has already demonstrated strong application potential. In the field of embodied intelligence, the research team developed customized tactile sensor arrays for robotic arms and heads, effectively endowing robots with sensitive electronic skin. They also created an intelligent glove integrating pressure and temperature sensors, enabling robots to identify objects through touch with an accuracy of up to 97 percent.

Beyond robotics, the approach shows promise in smart agriculture, aerospace and healthcare, including temperature and humidity monitoring, aircraft wing de-icing and wearable health sensors, while also demonstrating reliable adhesion on challenging surfaces such as polytetrafluoroethylene, damp wood and rough plaster.

Wang Xiaojing contributed to this story.

yandongjie@chinadaily.com.cn