Structural Design Strategies for Flexible, Stretchable EMI-Shielding Composites: Balancing Mechanical Compliance and Shielding Effectiveness

A comprehensive review is presented on the stringent requirements for electromagnetic compatibility (EMC) under complex deformation conditions in wearable and flexible electronics. It discusses polymer-based material strategies that balance high shielding effectiveness (SE), low density, stretchability, and stability, including blending, isolation networks, porous/foam, multilayer/gradient, and Janus asymmetric structures. The paper elaborates on the mechanisms of reflection, absorption, and multiple reflections, along with relevant evaluation methods. Furthermore, it outlines controllable fabrication techniques such as additive manufacturing, laser patterning, and hydrogel programming. The key design principles identified include adapting to deformation through extensible conductive geometries, achieving lightweight absorption via hierarchical porosity, buffering stress through electrical/mechanical gradients, and dynamically restructuring conductive pathways in the network. These principles aim to collaboratively overcome the traditional trade-off between "high SE and high stretchability." Future research should focus on multi-scale predictive design and standardized evaluation systems, the development of sustainable materials, scalable manufacturing processes, and the integration with functions such as sensing and thermal management.