A Stretch‐Tunable, Self‐Healing Liquid Metal‐Based Broadband Electromagnetic Wave Absorber

Traditional electromagnetic wave (EMW) absorbing materials are limited by their fixed electromagnetic parameters and structural characteristics, making it difficult to meet the demands of dynamic adjustment in complex electromagnetic environments. The dynamic tunability of wave-absorbing materials can be efficiently achieved by applying external forces to adjust the structure. However, repeated external forces can easily lead to structural damage and performance deterioration. To address these challenges, a flexible, broadband wave-absorbing material with adjustable absorption and self-healing capabilities is fabricated by combining a liquid metal (LM) based wave absorber with a self-healing polymer. Benefiting from LM's high conductivity and deformability and the polymer's self-healing capacity, the wave-absorbing material with high extensibility (∼3000% strain) not only exhibits an excellent effective absorption bandwidth (EAB) of 7.50 GHz in the X and Ku bands, but also can dynamically adjust its wave-absorbing performance under external force. Moreover, the structure and microwave absorption performances of this material can be self-healing at room temperature after damage, recovering ∼98% of its original EAB. Overall, this work provides crucial insights for the development of flexible electromagnetic materials.