Multifunctional NR/MXene/SiO₂ film with core-shell structure for all-weather thermal management and EM shielding

To address the growing demand for efficient thermal management and electromagnetic interference (EMI) shielding in smart wearable devices and flexible electronics, as well as to overcome the high energy consumption and poor environmental adaptability of traditional thermal management technologies, this study designs and fabricates a novel multifunctional natural rubber/MXene/silica (NR/MXene/SiO₂) composite film with a "core-shell" structure (SiO₂@MXene). This is achieved through chemical modification, electrostatic self-assembly, and dicumyl peroxide (DCP) vulcanization. The material adopts a "one-core, dual-effect" strategy, enabling the highly efficient synergy of active/passive thermal management and EMI shielding performance. Leveraging the physical confinement effect of SiO₂@MXene nanoparticles and the cross-linking reconstruction of the network structure, a well-developed, high-density thermal/electrical conductive network is constructed within the NR/MXene/SiO₂ composite film even at low MXene content. This significantly enhances the mechanical properties, thermal conductivity, electrical conductivity, and EMI shielding performance of the composite film. Results show that the VNM30Si20 composite film, containing only 30 wt% MXene and 20 wt% SiO₂ after vulcanization, exhibits outstanding comprehensive properties: high electrical conductivity (3400 S/m), high thermal conductivity (6.26 W/m·K), satisfactory mechanical performance (tensile strength increased by 338.6 % compared to pure NR), and excellent EMI shielding effectiveness (41.6 dB). The film also demonstrates remarkable stability during stress-strain cyclic tests, ensuring its reliability for practical applications. Furthermore, the material possesses prominent photothermal and electrothermal conversion capabilities. Under 1000 W/m² light intensity, the temperature rises to 102.7 °C after 100 s of irradiation; under a 3.5 V voltage, the temperature reaches 75.2 °C within 100 s. This efficient temperature control capability allows it to adapt to complex environments, showing broad application prospects in fields such as flexible electronics, aerospace thermal management, and new energy vehicle battery thermal management.