Rapid meniscus-guided printing of stable semi-solid-state liquid metal microgranular-particle for soft electronics

Abstract

Liquid metal (LM) is being regarded as the most feasible material for soft electronics owing to its distinct combination of high conductivity comparable to that of metals and exceptional deformability derived from its liquid state. However, the applicability of LM is still limited due to the difficulty of achieving its mechanical stability and intrinsic conductivity. Furthermore, reliable and rapid patterning of stable LM directly on various soft substrates at high-resolution remains a formidable challenge. In this work, meniscus-guided printing of ink containing polyelectrolyte-attached LM microgranular-particle (PaLMP) in an aqueous solvent to generate semi-solid-state LM is presented. PaLMP printed in the evaporative regime is mechanically stable, intrinsically conductive, and patternable down to 50 µm on various substrates. Demonstrations of the ultrastretchable (~500% strain) electrical circuit, customized e-skin, and zero-waste ECG sensor validate the simplicity, versatility, and reliability of this manufacturing strategy, enabling broad utility in the development of advanced soft electronics.