Multifunctional design integrating the flame-retardant and antifouling functionality into superhydrophobic cotton fabric

Here, we construct a stable flame-retardant superhydrophobic cotton fabric (FRS-CF) via simple impregnation method. The firstly deposited ammonium polyphosphate/zinc borate (APP/ZB) and silicon dioxide form an inorganic hierarchical structure, which not only endow the fabric with flame retardancy, but also provide appropriate roughness for the construction of superhydrophobicity coating. The latter deposited polydimethylsiloxane function as low surface energy materials to achieve the superhydrophobic performance, and the added epoxy resin could strongly increase the overall mechanical stability of the coating through providing interfacial adhesion. Importantly, the hierarchical micro-sized structure generated by the deposition of APP/ZB can supply particular protection for the constructed superhydrophobic coating from flame. Thus, the modified cotton fabric can self-extinguish during vertical combustion and display excellent flame retardancy with oxygen limitation index above 30 %. Additionally, the coating shows excellent water repellency, self-cleaning, anti-fouling properties and oil-water separation to a variety of liquids. The constructed coating holds durable flame-retardant and robust mechanical stability. After cycled friction test, the FRS-CF still maintains excellent superhydrophobicity and the oxygen limitation index remains above 30 %. We believe that the design of robust superhydrophobic/flame-retardant coating may advance the development of flame-retardant cotton fabric and provide new possibilities for the practical application of superhydrophobic coating.