Preparation and performance of flame-retardant, superhydrophobic cotton fabric with enhanced wash durability and self-cleaning properties

Here, we construct a flame-retardant, superhydrophobic cotton fabric by pre-treating it with polyethyleneimine (PEI) and 2,6,7-trioxa-1-phospha-bicyclo[2.2.2]octane-4-methanol-1-oxide (PEPA), followed by the application of a polydimethylsiloxane (PDMS) coating. The introduction of the PDMS layer not only imparted excellent superhydrophobic properties but also significantly enhanced the flame-retardant performance and wash durability of the fabric. The treated cotton fabric exhibited a remarkable transition from a hydrophilic to a superhydrophobic state, with an initial water contact angle of 148 degrees and a rolling angle of 25 degrees, and its limiting oxygen index (LOI) increased from 18.0 % for untreated cotton to 28.8 %, indicating greatly improved flame resistance. After 40 washing cycles, the water contact angle remained at 125.1 degrees, and the LOI was maintained around 24 %, demonstrating outstanding wash durability and longevity. Additionally, results showed a char residue of 41.7 % at 800 degrees C in a nitrogen atmosphere, with the peak heat release rate (PHRR) reduced by 35.6 % and the total heat release (THR) decreased by 40 %. The synergistic effects of this composite coating achieved multiple enhancements in superhydrophobicity, flame resistance, and wash durability, providing an innovative and effective solution for functional textiles in high-demand environments.