Hot–dog structured protective nanocoating for multifunctional cotton fabrics through spray–assisted layer–by–layer assembly

Multifunctional cotton fabrics were prepared by low–cost and environmentally–friendly spray–assisted layer–by–layer assembly to simultaneously achieve excellent self–extinguishing ability, antistatic property and antimicrobial activity. Especially, a novel hot–dog structured protective coating was designed by was designed with the incorporation of polyaniline (PANI) nanofibers between graphene sheets, which could exhibit unique structural advantages and give full play to the compound synergetic effect. More clearly, 3–aminopropyl triethoxysilane, ammonium polyphosphate and PANI were selected for achieving phosphorus–silicon–nitrogen synergism in the assembled layer, while PANI nanofibers doped with various organic acids were intercalated between adjacent graphene sheets for constructing more stable and efficient protective space. The optimized coated fabric exhibited the excellent self–extinguishing ability for 5 composite layers including phytic acid doped nanofiber, and its limited oxygen index was increased significantly from 18.1% for neat cotton to 35.1%. Moreover, the peak heat release rate and the total heat release values were greatly declined by 78.3% and 49.0%, respectively. Furthermore, a low sheet resistance of 264.7 kΩ/sq for antistatic property, as well as remarkable growth inhibition of E. coli and S. aureus could be observed. In addition, the coated fabrics also had good washing durability. Therefore, such eco–friendly and facile large–scale fabrication approach has great potentials in application for multifunctional advanced textiles and could be employed to various kinds of other cellulose fibers. Graphic abstract