Shape-adaptive electronics based on liquid metal circuits printed on thermoplastic films

Conformal electronics are of use in the development of wearable and biointegrated devices. However, existing methods of creating such electronics can lead to a lack of mechanical robustness, are limited in their range of materials or require specialized equipment and complex procedures. Here we report a heat-shrinking method for fabricating conformal electronics in which semi-liquid metal circuits are patterned onto thermoplastic substrates and then heated to induce shrinkage around a target object. We develop a semi-liquid metal that can withstand shrinkage deformation and maintain long-term electrical stability. We also develop simulation tools to consider the effect of the thermoplastic film’s deformation on the final circuit pattern, which allows precise circuit designs to be created on the initially planar film. The resulting shape-adaptive electronics exhibit high durability, with minimal conductivity change after 5,000 bending and twisting cycles. We illustrate the potential of the method by creating circuits for de-icing model aircraft, robot tactile sensors, fruit temperature and humidity sensors, fingertip pulse sensors, and smart bandages.