Elastic liquid metal composite with strain-independent EMI shielding properties

Abstract

Stable electrical and electromagnetic interference (EMI) shielding performance is crucial for the development of the new generation of flexible electronic devices, but maintaining stability under strain remains a challenge. This study presents the development of a composite elastomer utilizing eutectic gallium indium (EGaIn), characterized by its high flexibility in circuit design, excellent conductivity, minimal resistance variation, and consistent EMI shielding effectiveness under high strain conditions. The composite is engineered through the deposition of EGaIn particles within the lower layer of polydimethylsiloxane (PDMS), followed by the self-encapsulation of the upper PDMS layer. The robust electrical and EMI shielding properties of the PDMS/EGaIn composite elastomers under strain can be attributed to the internally formed defect-free liquid metal (LM) network. Furthermore, the composite elastomer's versatile circuit inscription capability on its surface, coupled with its resistance independence from the stress direction, underscores its functional versatility in electronic applications. Elastomers with exceptional stretch and strength hold great promise for applications in combat robotics and aerospace apparel. This biomimetic elastomer exhibits vast potential across diverse domains, including flexible electronics, flexible electromagnetic concealment, and aerospace technologies.