Halloysite nanotube-based nanofiber coatings with Ag-Cu nanoclusters for dual antimicrobial and anticorrosion applications

Abstract

Microbiologically influenced corrosion (MIC) accelerates the degradation of metal components in marine and water-handling systems, creating a need for coatings that combine barrier protection with antimicrobial activity. Here, we report a dual-function nanofiber coating in which Ag-Cu bimetallic nanoclusters are immobilized within halloysite nanotubes (Ag-Cu_NC/halloysite nanotube (HNT)) and embedded into electrospun polycaprolactone (PCL) nanofibers to form conformal coatings on copper. In artificial seawater, the nanocomposite coating improved corrosion performance under both abiotic and Lysinibacillus sp.-inoculated conditions by increasing charge-transfer resistance and yielding the lowest corrosion current densities. Notably, bare copper reached 17.8 × 10⁻⁶ A cm⁻² after 7 days, while neat PCL nanofibers reduced this value to 7.29 × 10⁻⁶ A cm⁻², and Ag-CuNC/HNT–PCL provided the strongest protection. The coating also stabilized the corrosion medium pH close to the initial value in abiotic tests and mitigated acidification in biotic tests. Ag-Cu nanoclusters exhibited broad-spectrum antimicrobial activity against Escherichia coli, Staphylococcus aureus, and Candida albicans, and inhibited Pseudomonas aeruginosa biofilm formation by 94.5% as free nanoclusters and 61% when incorporated into nanofiber coatings. Structural analyses confirmed successful dispersion of Ag-CuNC/HNT within the nanofiber matrix, supporting a scalable strategy for MIC mitigation and antimicrobial surface protection in marine environments.