Potent antifouling silver-polymer nanocomposite microspheres using ion-exchange resin as templating matrix

Biofouling of marine surfaces is a significant and complex problem especially in the shipping industry. This study seeks to develop a silver-polymer nanocomposite (Ag-PNC) system by synthesizing highly dispersed silver nanoparticles with narrow size distributions using Dowex protonated copolymer ion exchange resins as a templating matrix. Ag ions were introduced into the copolymer microbeads through an ion exchange process with silver nitrate, followed by chemical reduction using sodium borohydride to form metallic Ag on the surface of the microbead structure. Scanning electron microscopy (SEM) imaging revealed the uniform distribution of Ag nanoparticles with diameters between 20 and 60 nm on the surface of the microbeads, while UV–visible (UV–VIS) analysis showed the characteristic surface plasmon resonance for Ag nanoparticles ranging from 406 to 422 nm. Thermal stability of the nanocomposites was enhanced with the incorporation of Ag nanoparticles, with significant degradation occurring at 460 °C compared to 300 °C for the copolymer microbead, while the glass transition temperature of the Ag-PNCs increased from 130 °C to 323 °C. Significant inhibition of biofilm formation by Halomonas pacifica, a common marine bacteria responsible for initial marine fouling process, was observed, following treatment with Ag-PNC. Biocompatibility testing with human lung fibroblast and human keratinocytes show no significant toxicity to human cells. Toxicity testing of the Ag-PNC material with non-target marine microalgae Dunaliela tertiolecta and Isochrysis sp. also displayed no significant morphological changes, with cytostatic growth inhibition. These results strongly suggest that Ag-Dowex nanocomposites possess great potential to be an alternative to other antifouling agents due to their affordable, accessible and high yield production method.