Solidified Liquid Metal with Regulated Plasticity for Channel-Free Construction of 3D Structured Flexible Electronics

Abstract Gallium alloy based liquid metals (LMs) have shown great promise for soft and stretchable electronics in virtue of intrinsic fluidity and metallic conductivity. However, it has been a challenge by using LM to construct 3D structured circuits which are crucial for building flexible electronics with high integration. Hereby, taking advantage of the solid-liquid phase transition and plastic deformation of a Ga-10In LM alloy, we propose a novel strategy to fabricate LM based flexible electronic devices, in particular comprised of 3D circuits, without the need to pre-fabricate microchannels. We demonstrate applications including 3D interconnect arches for the integration of a multi-channel LED array, a 3D structured wearable sensor and a multilayer flexible circuit board for monitoring of finger movement. The current work provides a facile strategy for constructing LM based flexible electronics, which is of particular interest for building highly integrated electronics of hierarchical structure involving complicated 3D circuits.