Preparation of bio-based and phosphorus-free functional coatings for flame retardant, UV-resistance and antibacterial silk fabric

To endow silk with multifunctionality and expand its application fields, the silk fabric was treated with protocatechualdehyde to prepare a novel silk fabric with Schiff base structure (CAT@Silk). Then, CAT@Silk was immersed in iron (III) solution to chelate Fe 3+ to obtain flame retardant , antibacterial and UV-resistant silk fabric (CAT@Fe@Silk). Compared with the limiting oxygen index (LOI) value of the original silk, the CAT@Fe@Silk increased from 23.3 % to 35.1 %, and remained 32.4 % even after 20 laundering cycles (LCs), indicating excellent flame retardant durability. The UV protection coefficient of CAT@Fe@Silk was 67.74, which was higher than that of the original sample (21.02). In addition, CAT@Fe@Silk had good antibacterial effects against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ). This work constructed a dynamic cross-linking network that mimicked the adhesion of mussels generating from the complexation of catechol groups and Fe 3+ ions (catechol-Fe 3+ ), which not only endowed silk fabric with good flame retardancy, but also with UV resistance and antibacterial properties, demonstrating good potential application.