Hierarchical Interfacial Engineering Enables Durable Superamphiphobic Cotton Fabrics With Integrated Fire Safety and Photocatalytic Air Purification.

Sustainable cellulose textiles are promising for wearable protection, yet integrating durable superamphiphobicity, fire safety, and environmental remediation within a single cellulose substrate remains challenging. Herein, a silane-mediated stabilized organic-inorganic interface was constructed on cotton fabric through hierarchical interfacial engineering. First, a bio-based phytic acid/L-lysine interlayer was introduced to impart phosphorus-nitrogen synergistic flame retardancy. Subsequently, a molecularly designed poly(perfluorodecyl acrylate-co-butyl acrylate-co-methacryloxypropyl trimethoxysilane) acted as an interfacial bridge coupling the cellulose substrate with fluorinated TiO2 nanoparticles to form a robust hierarchical micro/nano-structure. Benefiting from this chemically coupled and structurally stabilized architecture, the fabric exhibited durable superamphiphobicity with water and oil contact angles above 150° even after washing, abrasion, tape-peeling, ultrasonication, corrosive media exposure, and prolonged ultraviolet irradiation. It also displayed excellent flame retardancy with a limiting oxygen index of 33.2%, while enabling efficient formaldehyde degradation for photocatalytic air purification, achieving removal efficiencies of 75.15% and 82.10% under static and dynamic conditions, respectively. These results demonstrate that silane-mediated interfacial coupling and polymer-assisted nanoparticle immobilization suppressed nanoparticle detachment and stabilizes the hierarchical architecture, enabling long-term synergistic liquid repellency, fire safety, and photocatalytic activity. Overall, this strategy offers a versatile route to durable multifunctional cellulose textiles for wearable protection and environmental remediation.