Lightweight, rigid, ordered RSF/PVA/MXene aerogels with Janus structure for effective electromagnetic interference shielding with low reflectivity

Electromagnetic interference (EMI) shielding materials principally attain shielding by reflecting electromagnetic waves through impedance mismatch caused by high conductivity, which inevitably leads to secondary electromagnetic wave pollution. Consequently, the development of multifunctional, low-reflection electromagnetic shielding materials remains a significant challenge. Materials that are lightweight, possess high mechanical strength, exhibit excellent electromagnetic shielding absorption, and demonstrate low reflectivity have historically been the focus of significant interest. Natural silk, lightweight and strong, is an ideal composite matrix. Regenerated silk fibroin (RSF) synthesized via a bottom-up approach and cross-linked with polyvinyl alcohol (PVA) forms an aerogel matrix with remarkable compressive strength. In accordance with the principle of integrating functional design with structural design, spherical NiFe₂O₄ particles were grown on the MXene surface via electrostatic self-assembly and combined with RSF/PVA as the aerogel absorptive layer, while RSF/PVA/MXene served as the reflective layer. A vertically oriented structure of Janus aerogel was prepared through sequential directed freezing. The resulting aerogel with 0.058 g/cm³ reveals the high compression strength (3.52 MPa). Reasonable functional and structural design enables aerogel to effectively dissipate incident electromagnetic waves through absorption, reflection, and reabsorption processes, achieving an average SE_T value of 48.05 ± 1.75 dB and reaching a minimum reflection coefficient of 0.19. Furthermore, the aerogel displays remarkable infrared stealth capabilities. This lightweight, rigid, multifunctional aerogel is poised to play a significant role in the field of next-generation electronic devices.