Construction of Hybrid Coatings Enabling Flame Retardancy and Ultraviolet Protection in Cotton Textiles

Cotton fabrics suffer from inherent flammability and limited resistance to ultraviolet (UV) radiation. These disadvantages severely restrict their safety and service lifetime in practical applications. In this work, a facile layer-by-layer self-assembly strategy was employed to construct a flame-retardant hybrid coating on cotton fabric surfaces. The coating is composed of polyethylenimine, phytic acid, and layered titanium carbide (MXene). It effectively combines the gas-phase and condensed-phase flame-retardant synergy of phosphorus and nitrogen with the physical barrier and thermal shielding effects of MXene nanosheets. As a result, the modified cotton fabrics exhibited markedly enhanced flame retardancy, achieving a limiting oxygen index of up to 37.6 vol %. Microscale combustion calorimetry tests demonstrated pronounced reductions in the peak heat release rate and total heat release, accompanied by a high char residue of 26.4 wt % at 800 °C, indicating significantly improved thermal stability and condensed-phase protection. In addition, the coating imparted excellent UV-shielding performance, with UV A and UV B transmittance reduced to 2.22% and 1.82%, respectively, and a high UV protection factor of 52.29. This study provides an effective surface-engineering strategy for the development of cotton textiles with simultaneous fire safety and UV protection. It offers both mechanistic insights and practical potential for advanced protective and functional textile applications.