Flexible and Thermally Induced Switchable Fire Alarm Fabric Based On Layer-by-Layer Self-Assembled Silver Sheet/Fe₃O₄ Nanowire Composite

Textiles with fire detection will appeal for the interior decoration of houses and play a critical role in public security. Herein, we fabricated a sandwichlike fire alarm fabric (Ag@Fe3O4-MS) based on Fe3O4 nanowire (NW) arrays and fish-scale-like silver sheets, designed by in situ layer-by-layer assembly on the surface of polypropylene (PP) nonwoven fabric. The Ag@Fe3O4-MS sensor has fish-scale-like silver sheets as self-assembling electrode layers on the upper and lower sides of fabric, which can be tailored into various shapes and integrated into other flexible electronics. The sensor provides a real-time monitoring strategy for early warning fire detection (below 100 °C). At room temperature, the fabricated Ag@Fe3O4-MS sensor is electrically insulating, while it switches to an electrical conductor when exposed to flame. In view of its fast response time (2 s) and sustained working time (at least 15 min), the sensor with a connected alarm light can immediately alert people of house fires. More importantly, this sensor can provide additional real-time information on the fire location and reliable real-time monitoring of fire rekindling. The sensor was exposed to fire for successive cycles with an average response of I = 43 mA, confirming the reliable repeatability to detect fires. This ultralight, flexible Ag@Fe3O4-MS sensor could have broad applications in home safety. Moreover, the sandwichlike design provides a reliable strategy to modify household fabric items to provide a fire warning function.