Aramid nanofiber-reinforced graphene oxide frameworks for durable and flame-resistant fire warning sensors

Currently, fire warning sensors utilizing nanomaterials gained attention in research and development sectors. Among these, graphene oxide (GO)-based sensors stand out for their promising features in fire detection systems. However, GO sensors still suffer from poor durability, short-alarming time and poor solvent resistance. In this study, GO is modified with melamine diborate (M·2B) and incorporated into aramid nanofibers (ANFs) to develop GO-MB@ANFs nanopaper via mechanical mixing followed by vacuum-assisted filtration self-assembly. ANFs cross-linked graphene oxide sheets within a 3D scaffold while M·2B plays a critical role in enhancing flame retardancy of GO-based nanopaper. GO-MB@ANFs nanopaper features tensile strength of 132.3 MPa and toughness of 837 MJ/m³ in comparison with 10 MPa and 2 MJ/m³ for pure GO-based nanopaper. The GO-MB@ANFs nanopaper demonstrated remarkable flame resistance; it can endure direct exposure to an alcohol flame for 120 s with exceptional thermal stability. Additionally, it showed excellent features as a fire-warning sensor; GO-MB@ANFs exhibited a rapid response time of 0.73 s and an extended alarm duration exceeding 1260 s at 300 °C. Moreover, the supramolecular cross-linking of M·2B and ANFs endowed the GO nanopaper with excellent solvent resistance, maintaining its integrity even under harsh acidic and alkaline environments such as H₂SO₄, NaOH, and NaCl. The current study provides a new strategy for developing a robust, durable and cost-effective GO-based fire alarm sensor for diverse applications in construction and transportation industry.