A highly efficient flame retardant nacre-inspired nanocoating with ultrasensitive fire-warning and self-healing capabilities

Design and exploitation of flame retardant coatings with sensitive fire-warning response and self-healing capability are urgently needed to decrease the fire risk of combustible materials. Herein, we reported the fabrication of a novel multifunctional flame retardant nanocoating created by using graphene oxide (GO) and functional cellulose (FC) via one step self-assembly. The prepared nacre-like nanocoating endowed many kinds of combustible materials (including polypropylene, polyurethane foam and wood) with exceptional fire safety. All the coated substrates were self-extinguished in the flame retardant tests. More importantly, when being attacked by fire at the very early stage, it triggered the fire-warning in less than three seconds through the dramatic decrease of electrical resistance. Moreover, the nanocoating exhibited outstanding self-healing capability at room temperature. Due to the multiple hydrogen bondings between the ureido pyrimidinone groups on FC, the damaged coating could be healed successfully and almost recovered to its original integrated performance. Our work provides a new and effective route to remarkably improve the fire safety of the combustible materials, exhibiting an enticing prospect for its application in the fields of building, transportation and electrical equipment.