A Metalgel with Liquid Metal Continuum Immobilized in Polymer Network

Abstract Gels are formed by fluids that expand throughout the whole volume of 3D polymer networks. To unlock unprecedented properties, exploring new fluids immobilized in polymer networks is crucial. Here, a new liquid metal‐polymer gel material termed “metalgel” is introduced via fluid replacement strategy, featuring 92.40% vol liquid metal fluid as a continuum immobilized by interconnected nanoscale polymer network. The unique structure endows metalgel with high electrical conductivity (up to 3.18 × 10 6 S·m ‒1 ), tissue‐like softness (Young's modulus as low as 70 kPa), and low gas permeability (4.50 × 10 ‒22 m 2 ·s ‒1 ·Pa ‒1 ). Besides, metalgel demonstrates electrical stability under extreme deformations, such as being run over by a 4.5‐metric‐tonne truck, and maintains its integrity in various environments for up to 180 days. The immobilization of high‐volume‐fraction liquid metal fluid is realized by electrostatic interactions is further revealed. Potential applications for metalgel are diverse and include soft electromagnetic shielding, hermetic sealing, and stimulating/sensing electrodes in implantable bioelectronics, underscoring its broad applicability.