Shape memory effects mediate electromagnetic interference shielding performances of hybrid fibroin-carbon nanotube sponge

This research integrates the shape-memory effect and electromagnetic interference (EMI) shielding performance by constructing a hierarchical silk fibroin/carbon nanotube (SF/CNT) sponge composite. The achieved smart composite materials exhibit both flexible shielding mechanism and tunable EMI shielding performance with tunable range of more than 350 %. The smart EMI shielding performances comes from the conductive CNT sponge with both porous and zigzag structures combining shape-memory effect originating from the pressure induced conformation transition of fibroins. Beyond multi-functionalization, this study also achieves a synergistic coordination of distinct properties, yielding exceptional tunable EMI shielding performance and excellent reusability over multiple compression-recovery cycles, providing insights for designing next-generation tunable electromagnetic protection systems and portable electronic devices. Electromagnetic interference (EMI) shielding materials generally exhibit confirmed performance due to their intrinsic structures and composition, which do not vary once constructed. Here in this study, by combining the recoverable conformational transition of silk fibroin (SF) with the EMI shielding properties of carbon nanotube sponge (CNTS), we successfully constructed the hybrid SF/CNTS with tunable high EMI shielding performance. The silk fibroin underwent a reversible secondary conformational transition, in which α-helices/random coils transform into β-sheets, enabling the shape memory effect of SF/CNTS that is associated with structural changes and mediates EMI shielding efficiency. Specifically, the 6 mm-thick SF/CNTS composite exhibits an average EMI SE of 62 dB across the X-band, which decreases to 53 dB at a 90% compressive strain. Furthermore, the hierarchical SF/CNTS architecture allows the EMI SE to be dynamically tuned within the range of 35 dB to 10 dB, demonstrating that structural regulation is effective across both macro and micro scales. Our study presents a strategy for designing smart EMI shielding materials, offering valuable insights into the development of next-generation tunable electromagnetic protection systems.