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• Nacre-like GO-PTA paper is prepared by evaporation-induced self-assembly method. • Fire sensor-based GO-PTA exhibits ultrasensitive and durable warning response. • Enhancement in fire resistance of GO is attributed to in situ phosphorus doping. A novel nacre-like flame-retardant paper based on graphene oxide (GO), and phytic acid (PTA) is fabricated via evaporation-induced self-assembly. This facile method is time saving and low energy consuming. A facile approach is proposed to improve thermal oxidative stability of GO paper by in situ phosphorus doping during flame exposure. Then fire-alarm system is designed based on the high-temperature thermal reduction characteristic of GO. The GO paper functionalized with PTA (GO-PTA) can provide ultrasensitive, reliable and longtime fire early-warning signal. Fire alarm can be triggered at approximately 0.50 s when GO-PTA samples are attacked by fire. Phosphorus atoms are in situ doped into graphene layers during fire exposure, endowing GO-PTA paper with outstanding thermal oxidative stability, and thus alarm duration time of GO is greatly improved. The work develops advanced fire detection and early-warning sensors that provide reliable and continuous signals, which provide more available time for fire evacuation. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract To overcome the shortcomings of inefficiency in the preparation of covalent organic frameworks (COFs) nanosheets by ball milling, a gram-scale method to preparing COFs nanosheets with butyl lithium as the intercalation agent has been proposed. A significant advantage of COFs nanosheets that display good interface compatibility has been discovered through experiments. Due to their special organic crystalline structure and hydrogen bonding effects, COFs nanosheets without any modification show good interface compatibility, good dispersibility and enhancement in the mechanical properties of PVA matrix even at the loading as high as 9.6 wt%. Meanwhile, thermal, hydrophobic and flame retardant performances of PVA/COFs nanosheets nanocomposite have also been strengthened. This work should provide a guidance for the preparation of multifunctional nanocomposites with high loading. [ABSTRACT FROM AUTHOR]