Interfacial Polymerization Using Acyl Chloride-Functionalized Porphyrin Comonomers toward Robust PA-66 with Type I/II Dual Photodynamic Antibacterial Durability

The growing threat of bacterial contamination and antibiotic resistance urgently requires functional antibacterial textiles. Photodynamic antibacterial approaches relying on reactive oxygen species (ROS) provide a promising alternative to achieve safe and long-term antimicrobial protection. Herein, a fabrication strategy was developed to construct intrinsically photodynamic antibacterial polyamide 66 (PA-66) yarns via interfacial polymerization. Acyl chloride-modified porphyrin (TCPP-Cl4), acting as a ternary monomer, was covalently grafted onto PA-66 molecular chains via interfacial polymerization. Subsequent drawing, spinning, and twisting yielded functional TCPP-Cl4-PA-66 yarns that preserved the favorable mechanical performance and thermal stability of PA-66. Physically blended TCPP/PA-66 yarns were also prepared as reference samples. Compared with TCPP/PA-66 yarns, the covalent anchoring process effectively reduced photosensitizer leaching and improved ROS generation capacity. As a result, TCPP-Cl4-PA-66 yarns achieved antibacterial efficiencies of 97.4 ± 1.3% against Staphylococcus aureus (S. aureus) and 94.0 ± 2.8% against Escherichia coli (E. coli). Furthermore, this covalent immobilization also endowed the yarns with favorable washing resistance, maintaining stable photodynamic antibacterial activity against both strains after multiple washing cycles. Interwoven fabrics fabricated from TCPP/PA-66, TCPP-Cl4-PA-66, and cotton yarns also exhibited desirable photodynamic antibacterial performance. This work provides a facile strategy for constructing photodynamic antibacterial textile materials with good stability.