Lotus leaf-inspired and multifunctional Janus carbon felt@Ag composites enabled by in situ asymmetric modification for electromagnetic protection and low-voltage joule heating

Abstract

Multifunctional materials with electromagnetic interference (EMI) shielding, thermal management, sensing, and comfort characteristics are greatly desirable in the application of intelligent and wearable devices. However, the multifunctional integration and low energy consumption of wearable devices remain a great challenge. Herein, inspired by the lotus leaf, a strategy of in situ asymmetric modification is proposed to construct a highly conductive and multifunctional Janus carbon felt@Ag nanoparticles (AgNPs) composite. Due to the uniform AgNPs layer together with carbon fiber, the resultant multifunctional composite demonstrates high electric conductivity with shielding effectiveness (SE) of ∼65 dB at a thickness of 270 μm. The composite also exhibits a great joule-heating property with the saturated temperature of 61.1 °C at an extremely low voltage of 1 V, as well as boosted thermal durability. More importantly, the asymmetrical feature constructed by a unique nano-micro structure endows the composite with simultaneously hydrophobic and superhydrophilic properties, which may integrate sweat removal and waterproof functions for manufacturing comfortable wearable devices. In addition, the carbon felt@AgNPs composite displays enormous potential as a sensor for human motion monitoring. Therefore, this work would provide a vital sight for fabricating advanced wearable equipment with EMI shielding, thermal management, and multifunctional applications.