Hydrophobic and anti-fouling polyelectrolyte complex coating for durable flame-retardant cotton fabric

Surface treatment is one of the most effective ways to impart flame retardancy to fabrics, woods, etc. Especially, water-soluble polyelectrolyte complex (PEC) coating deposition is one of the most environmentally benign and facile technologies. However, durability, especially washing durability, remains a challenge for almost all PEC coated materials. In an effort to keep the desirable flame retardancy of cotton despite multiple washings, in this work, perfluorodecyltrichlorosilane modified polyethylenimine (PEI) was prepared to coat onto the ammonium polyphosphate (APP) based PEC coating. The extra 2 wt% fluorinated PEI has not only retained the high LOI value (28.5%) of 10 wt% PEC-coated cotton, but also endowed this coated cotton with high water contact angle of 117°. Also, the treated cotton displayed excellent antifouling performance to milk, coffee, honey, cola and ink. Notably, it still preserved self-extinguishing behavior on a vertical flame test and high LOI value of 26.5%, after vigorously stirring in water at 40 °C for 20 times. This facile and efficient method could provide a new strategy for durable flame-retardant cotton fabric against humid and pollutant conditions.