Eco-friendly fabrication of antibacterial cotton fibers by the cooperative self-assembly of hyperbranched poly(amidoamine)- and hyperbranched poly(amine-ester)-functionalized silver nanoparticles

Abstract

Wastewater has long been a highly important insurmountable problem in the textile industry. Since the rapid development of antimicrobial silver nanoparticle (AgNP)-coated textiles in the recent several decades, AgNP-containing wastewater produced in the finishing process has gradually posed a greater threat to the ecological environment than that by traditional organic dyes because of the former’s strong antimicrobial ability. Herein, we designed an environmentally friendly, energy-efficient, bottom-up nanocoating strategy for cotton fibers through the cooperative self-assembly of heterogeneous AgNPs functionalized by amino-terminated hyperbranched poly(amidoamine) (HBPAA) and hydroxyl-terminated hyperbranched poly(amine-ester) (HBPAE), respectively. The HBPAA-functionalized AgNPs possessed a positive surface charge of +40.8 mV and dense amino end groups, whereas the HBPAE-functionalized AgNPs had a slightly negative surface charge (−15.8 mV) and abundant OH end groups. Therefore, given the intermolecular recognition and interactions between HBPAA and HBPAE, the heterostructured AgNPs selectively co-precipitated on the natural fiber surfaces. Our scanning electron microscopy (SEM), field emission SEM, and X-ray photoelectron spectroscopy studies confirmed that the heterostructured AgNPs were uniformly anchored on the surface of the cotton fibers, indicative of their excellent physical and prolonged chemical stability. The coated cotton fibers showed excellent antibacterial activity. At the extremely low Ag content of 3 mg/g, the coated cotton fibers showed satisfactory antibacterial effects with over 99% antimicrobial rates. The developed cooperative self-assembly strategy demonstrated a nearly complete AgNP uptake by natural fibers and the ability to precisely control silver content. As such, the cooperative self-assembly method promises a high potential for practical production.