Construction of shape-memory carbon foam composites for adjustable EMI shielding under self-fixable mechanical deformation

The design and fabrication of novel electromagnetic interference (EMI) shielding materials with the capability of realizing convenient performance regulation under self-fixable mechanical deformation is becoming an urgent challenge due to the increasingly complex application conditions. To alleviate this problem, the composite construction that consisted of compressible carbon foam (CF) and shape-memory polymer coating was proposed, and the demo samples were fabricated by coating trans-l,4-polyisoprene (TPI)-MXene layer onto compressible wood-derived CF with multilayer microstructure. The resultant composites (thickness: ~2–10 mm, density: ~150 mg/cm3) with enhanced shielding effectiveness (SE) of ~25.3–44.7 dB could not only adjust their SE value by changing their compressive strains, but also possess excellent thermally/electrically stimulated shape-memory behaviors that can be easily deformed and recovered as being heated and fix a temporary shape at low temperature, thereby realizing convenient SE regulation under self-fixable mechanical deformation. Moreover, based on different initial SE performance and compression conditions, the EMI SE of the composites can also be tuned within effective SE range of >20 dB, or switched between >20 and <20 dB, exhibiting smart function-tunable or function-switchable feature, which provides a promising platform for developing novel EMI shields for smart electromagnetic response applications.