Superhydrophobic SiO2-protected MXene/ sericin/PVA flexible films for enhanced mechanical strength, infrared stealth, and EMI shielding

Sericin bridging builds H-bond networks, delivering 91 MPa strength and 14.3 MJ m −3 toughness. • Discontinuous SiO 2 enables MXene-dominated IR stealth with a 107.8 °C temperature drop. • 34.4 dB EMI shielding is achieved at a thickness of only 63 μm. • PVA/SS matrix and superhydrophobic layer (155.9°) ensure long-term stability. • Gradient architectures enable reliable piezoresistive response for motion sensing. Developing flexible materials with integrated infrared (IR) stealth, electromagnetic interference (EMI) shielding and long-term stability is essential for personal protection and smart wearables. Traditional MXene composites suffer from weak interfacial bonding, poor mechanical properties, easy oxidation, and the functional trade-off between hydrophobic protection and infrared stealth. Herein, a synergistic strategy of multi-level interfacial bridging and discontinuous superhydrophobic barrier was proposed to fabricate MXene/sericin (SS)/PVA flexible films with a micro-nano SiO 2 protective layer. Sericin acts as an interfacial bridge to construct dense and reversible hydrogen-bond networks, effectively improving mechanical performance. The optimized SMSP-35 film with 35 wt% MXene achieves a tensile strength of 91 MPa, a toughness of 14.3 MJ m −3 and 19.2% elongation at break. The discontinuous SiO 2 coating maintains the low-emissivity feature of MXene in the 8–14 μm band, reducing the radiation temperature of a 200 °C target by 107.8 °C. The film (63 μm) realizes an EMI shielding efficiency of 34.4 dB. Combined with the physical barrier of PVA, interfacial bridging effect of SS and superhydrophobic SiO 2 layer (155.9°), the film retains nearly original shielding performance after 5-month ambient exposure with outstanding oxidation resistance. It also exhibits reliable strain response for human motion monitoring. This work addresses the challenges associated with multifunctional incompatibility and limited stability, providing a viable design strategy for flexible multifunctional protective materials. Download: Download high-res image (416KB) Download: Download full-size image