Bio-inspired fabrication of multifunctional cotton fabric with durable flame retardancy and superhydrophobicity for oil-water separation application

In response to the growing demands for cotton fabric across different applications, the development of multifunctional fabric has garnered significant attention. However, it is still a great challenge to simultaneously realize functions such as flame retardancy, washing durability and water repellency of fabric. In this work, an eco-friendly multifunctional cotton fabric (CF-PZF/PDMS) with durable flame retardancy and superhydrophobicity was successfully prepared through nanotechnology and surface modification methods, which included the impregnation with phytic acid (PA), in-situ growth of zeolitic imidazolate framework-8 (ZIF-8) and spraying of polydimethylsiloxane (PDMS). Due to the synergistic effect of nitrogen, phosphorus and silicon elements, as well as the catalytic charring effect of transition metal (Zn 2+ ) in ZIF-8 nanoparticles, CF-PZF/PDMS fabric had excellent flame retardancy and washing durability, with a limiting oxygen index (LOI) of 34.5% and a char length of 38 mm. Even after 20 washing cycles, CF-PZF/PDMS fabric still maintained an LOI value of 29.6%, exhibiting great self-extinguishing. Furthermore, the rough structure with hierarchical micro/nano-scale protuberances constructed by ZIF-8 and low surface energy of PDMS endowed CF-PZF/PDMS fabric with excellent superhydrophobicity and self-cleaning properties, evidenced by a water contact angle (WCA) of 152.8°. Notably, this fabric possessed excellent selective oil absorption capacity, high efficiency (more than 97%) in separating various oil–water mixtures, as well as superior stability in repetitive use. This study presents a straightforward method for fabricating multifunctional cotton fabric, which has promising applications in the field of advanced functional textiles and oil–water separation. Graphical abstract