Simple coating method for the preparation of superhydrophobic flame-retardant cotton fabrics with excellent mechanical stability performance

Cotton fabrics are widely used in many fields due to their softness, comfort and breathability. Regrettably, cotton fabrics are easily ignited and extremely susceptible to contamination owing to their high hydrophilicity. Therefore, it is necessary to give cotton fabrics flame retardant and superhydrophobic properties to meet the demands of different scenes. In this report, ammonium polyphosphate, pentaerythritol and melamine cyanurate were selected as the main ingredients for the preparation of flame retardant solution, which was deposited on the surface of cotton fabrics by dip-coating to prepare flame retardant coatings. Secondly, fluorinated polydimethylsiloxane was obtained by cross-linking reaction between fluorinated modifier perfluorodecyltriethoxysilane and polydimethylsiloxane, which was combined with nano-silica to prepare superhydrophobic solution. The superhydrophobic solution was covered on the upper layer of the flame retardant cotton fabric by spraying method to prepare the superhydrophobic flame retardant cotton fabric. The cotton fabrics prepared exhibited excellent superhydrophobicity (water contact angle of 162.1 degrees and sliding angle of 2.5 degrees) and anti-fouling property. It also had a superior mechanical stability and durability, with superhydrophobicity almost unchanged after 10 abrasion tests with sandpaper cycles and a 10 wash cycles test. Most importantly, the prepared flame-retardant hydrophobic cotton fabric could realize the flame self-extinguishing within 20 s in the vertical combustion experiment, and its limiting oxygen index (LOI) value was 29.4 %, which demonstrated the outstanding flame-retardant performance.