Morphology and Properties of Flame-Retardant Superhydrophobic Polymer Coatings Deposited on Cotton Fabrics from Supercritical CO₂

An approach for deposition of a multifunctional coating on the surface of cotton fabric using supercritical carbon dioxide (sc CO2) is explored. Polyphosphazene-based microspheres to be used for deposition are synthesized, and their thermal behavior is studied using thermogravimetric analysis. The morphologies of hydrophobic polymer and polyphosphazene microspheres deposited on cotton fibers from acetonitrile and from sc CO2 are compared using scanning electron microscopy. The results suggest that the use of sc CO2 as a medium allows for uniform deposition of both the copolymer and the microspheres. The water contact angle for the treated fabrics is revealed to be above 170°. A certain increase in limiting oxygen index for the treated fabrics is observed. We demonstrate that sc CO2 can be successfully used as a medium to deposit the microspheres onto cotton textile materials. With further optimization, the suggested procedure can lead to the development of a process of multifunctional textile finishing in which supercritical carbon dioxide is used as a process medium instead of water. The technology described may help in eliminating such pressing environmental problems of the textile finishing industry as high energy consumption and possible water pollution.