Molecular bridge crosslinking and nano-ZnO synergistically construct fluorine/silicon-free multifunctional cotton fabric coatings

Fluorine/silicon-free waterborne polyacrylate/nano-ZnO composite cotton fabric coatings (EPSAs) were developed to address the potential environmental and health risks posed by traditional fluorine-containing finishing agents. A molecular bridge constructed by 1,6-hexanediol diacrylate (HDDA) formed a crosslinked network, promoting synergistic directional alignment of tert-butyl and long-chain alkyl groups to create a low-surface-energy chemical hydrophobic barrier. Meanwhile, the polyvinyl alcohol (PVA) modified nano-ZnO not only improved the dispersibility of nano-ZnO, but also enhanced its mechanical stability through the hydrogen bonding interaction and interpenetrating network structure between PVA molecular chains and the polyacrylate main chains. Additionally, the PVA-modified nano-ZnO and polyacrylate jointly constructed a micro-nano rough structure on the fiber surface. This effectively inhibited water adsorption and enhanced impermeability. This hierarchical synergistic effect enabled the optimized EPSA 4 coating membrane to achieve 5.4 % water absorption over 7 d while the coated cotton fabric demonstrated a 128° water contact angle with 2.5 h effective water impermeability that remained stable after 50 washing cycles. Additionally, the coating significantly enhanced the cotton fabric's UPF value from 30.5 to 93.3 and achieved antimicrobial efficiencies of 99.98 % against Escherichia coli and 99.95 % against Staphylococcus aureus . By retaining their inherent breathability, this innovative coating system provided cotton fabrics with long-term hydrophobicity, antimicrobial functionality, and UV resistance, offering an environmentally sustainable multifunctional textile solution for applications including medical protective garments, outdoor technical textiles, and other sectors requiring integrated performance and eco-friendly characteristics.