Recyclable Printed Liquid Metal Composite for Underwater Stretchable Electronics

Multifunctional stretchable conductors are crucial components in fully stretchable circuits for wearable bioelectronics. Conductive composites made from liquid metal (LM) fillers and polymer matrices have garnered significant interest due to their high electrical conductivity, adjustable mechanical properties, biocompatibility, and recyclability. Herein, a printable LM composite is developed using a custom-designed block copolymer to ensure electromechanical stability in both wet and dry conditions. The LM composite demonstrates high conductivity (around 10⁵ S m^{- 1}), stretchability up to 500%, and maintains stable resistance with cyclic strain ranging from 0 to 50% for over 16 h, in both ambient and aqueous environments. Furthermore, bulk LM is successfully recovered from printed composites using green solvents, supporting the composite's recyclability.