Preparation and controlled coating of hydroxyl-modified silver nanoparticles on silk fibers through intermolecular interaction-induced self-assembly

Highlights: • Hydroxyl-modified silver nanoparticles possess a small and uniform size. • The self-assembly process is fast, efficient, and environmentally-friendly. • The silver content of coated silk fibers can be precisely controlled up to 8 mg/g. • Silk fibers gain satisfied antibacterial activity when silver content is over 1.5 mg/g. Herein, we report an efficient and environmentally-friendly approach for the preparation of silver nanoparticle-coated silk fibers (SFs) through self-assembly of hyperbranched poly(amine-ester)s modified silver nanoparticles (HBPAE/AgNPs) on hyperbranched poly(amidoamine)s modified silk fibers (HBPAA/SFs) driven through intermolecular interactions between hydroxyl-terminated HBPAE and amino-terminated HBPAA. The HBPAE/AgNPs had a particle size of 11.8 nm and were slightly negatively charged. The self-assembly process was conducted by successively impregnating the SFs with HBPAA and HBPAE/AgNPs solutions. Up to 160 mg/L of HBPAE/AgNPs could completely self-assemble onto HBPAA/SFs (2 g) at room temperature within 10 min, allowing the Ag content of HBPAE/AgNP-coated HBPAA/SFs to be precisely controlled up to 8 mg/g by simply adjusting the concentration of the AgNPs. The antibacterial activity of HBPAE/AgNP-coated HBPAA/SFs was dose-dependent and the minimum Ag content was determined as 1.5 mg/g with an inhibitory rate of over 99%. Further characterization demonstrated that the as-prepared HBPAE/AgNP-coated HBPAA/SFs have unique structural features including well-dispersed NPs on the surface and good chemical stability. The developed self-assembly technology may provide a simple, efficient, and environmentally-friendly coating strategy for the precise control of Ag content on coated fibers, which is important for the quality control of antibacterial textiles.