Self‐Destructible Electromagnetic Interference Shielding Films

Abstract In response to the increasing utilization of communication technology, there is a growing need for electromagnetic interference (EMI) shielding materials to adapt to diverse application scenarios. In this study, the self‐destructible EMI shielding films (SEFs) that possess the unique capability to reduce conductivity and shielding efficiency through temperature elevation are introduced. The SEFs effectively fulfill the requirement of triggering EMI shielding failure under specific conditions, which can be achieved by simply spraying a mixture of thermally expandable microspheres (TEMs), conductive fillers, and resin substrates. The segregated structures resulting from the incorporation of TEMs confer exceptional electrical conductivity and superior EMI shielding performance at low conductive filler content. When the ambient temperature surpasses the glass transition temperature of the TEM shell, the thermally expandable characteristics cause a disruption in the conductive path of the SEFs, leading to a significant decline in shielding effectiveness. Additionally, the SEFs exhibit outstanding Joule heating effects (90 °C) at low voltage (1.5 V) within a brief time frame (10 s). Importantly, when employed as Joule heaters, the SEFs possess an intrinsic safety mechanism that automatically ceases operation in the event of circuit overload, thus minimizing any potential risks.