Multifunctional 2D-3D heterogeneous MXene@ZIF-8 coated cotton/lyocell blended fabrics for fire protection, motion detection and UV-resistance

Multifunctional cellulose fabrics with flame retardancy, electrical conductivity and UV resistance are expected to be used in the next generation of wearable flexible sensors, so there is an urgent need to develop novel coating systems that improve the natural properties of cellulose fabrics and give it more functionality. Here, a 2D-3D hetero-structured multifunctional coating consisting of titanium carbide (Ti3C2Tx MXene), zeolitic imidazolate framework-8 (ZIF-8) and phosphonitrilic chloride trimer (PPZ) was constructed on cotton/lyocell blended fabrics (C/L) by a one-pot impregnation method. Briefly, C/L first interacted with MXene via hydrogen bonding, and then the ZIF-8 encapsulation system grew in situ on MXene. The optimal sample obtained, named as MXene@ZIF-8@PPZ-C/L, combines flame retardancy, human motion detection and UV resistance. Compared to the untreated C/L, MXene@ZIF-8@PPZ-C/L exhibited a limiting oxygen index value of up to 30.8%, with peak heat release rate and total heat release values reduced by 65.7% and 15.8%, respectively. Meanwhile, MXene@ZIF-8@PPZ-C/L with an electrical conductivity of 24.4 s/m was able to sense human movement stably and continuously. Moreover, MXene@ZIF-8@PPZ-C/L also showed a high ultraviolet protection factor. In short, this work provided a simple method for fabricating new-generation multifunctional flexible wearable smart fabrics.