A natural clay-based Janus micro-nanosystem with ultra-temperature resistant piezoresistive sensing and self-switching fire warning for smart fire safety

Fire poses a significant threat to human lives, and effectively mitigating the occurrence of fire and conducting timely rescue operations post-fire remains a huge challenge in fire safety field recently. Hence, there is an urgent need to develop novel materials that can be efficiently integrated into fire safety strategies to minimize or eliminate fire-related casualties. Herein, inspired by the “mortar&brick” concept, an asymmetric “Janus” MXene@Vermiculite/Sodium alginate (MXene@V/SA) composite paper is constructed by layer-by-layer assembly of two-dimensional (2D) sheets. The composite paper integrates fire monitoring, early warning, alarm and rescue for fire safety. Specifically, the MXene@V/SA composite paper features temperature visualization for temperature monitoring and has a self-switching function suitable for smart fire alarm sensor (FAS) systems. By combining wireless communication technology, it can provide sensitive fire early warning (∼3.6 s) and efficient alarm transmission. Additionally, due to the “high-temperature shielding effect” of Vermiculite (V) and the piezoresistive sensing of MXene, the resulting MXene@V/SA composite paper exhibits exceptional flame retardant and thermal insulation properties, as well as the ability for real-time signal monitoring. Signal transmission is maintained even after withstanding extreme high temperature (∼1300 °C). It can be used as a wall-paper sensor to monitor distress signals from people trapped by fire, providing a new solution for emergency scenarios such as fire rescue and search. Therefore, MXene@V/SA composite paper not only broadens the application scope of MXene materials in the fire safety field but also serves as a platform to advance intelligent FAS and improve the efficiency and accuracy of rescue techniques.