Ultra-Thin Flexible Bacterial Cellulose Janus Conductive Films for Electromagnetic Interference Shielding and Joule Heating

This is the authors' abstract. We don't add key points for this paper.

Lightweight electromagnetic interference (EMI) protection increasingly requires shielding materials that retain mechanical reliability while minimizing thickness and integrating complementary functions. Here, an ultrathin bacterial cellulose/MXene/silver nanowire (BMA) Janus composite film was fabricated by vacuum-assisted filtration to combine EMI shielding and Joule heating within a mechanically compliant structure. The resulting film exhibits a tensile strength of 77.35 MPa and a fracture strain of 4.27%. At an AgNWs loading of 0.9 mg, the optimized BMA5 film shows a sheet resistance of 0.429 Ω sq−1. Despite a thickness of only (12.0 ± 0.1) μm, it achieves an EMI shielding effectiveness above 52.00 dB. The Janus film also reaches a surface temperature of 126 °C at an applied voltage of 2.5 V and maintains a stable temperature for more than 3000 s. These results show that spatially separating the structural, conductive, and electromagnetic functions of BC, MXene, and AgNWs provides an ultrathin composite platform that combines shielding performance, mechanical flexibility, and electrothermal response for lightweight electromagnetic protection and thermal management.