Lingnan Wang, Chengxiang Li, Zhou Rao, Xiao Li, Huifen Huang, Mengsai Li, Liang Wang, Zefeng Wang, Danfeng Deng, Ying Fu
Copper-based metal-organic frameworks (Cu-MOFs) have emerged as promising antibacterial materials by virtue of their porous architectures and tunable metal ion release profiles. Nevertheless, conventional Cu-MOF coatings that rely on a single Cu2+ release-mediated bactericidal mechanism suffer from initial burst release, inadequate long-term efficacy, and an inherent inability to suppress initial bacterial adhesion. To overcome these limitations, we report a hierarchical, dual-mode antibacterial coating strategy with high bio-based content. The bottom layer employs a high bio-based waterborne polyurethane (WPU) as the film-forming matrix, within which Cu-MOF is physically embedded. The polymer matrix acts as a diffusion barrier to modulate sustained Cu2+ release while providing a robust adhesion interface for the top layer microspheres. The top layer comprises microspheres fabricated via copolymerization of isobornyl acrylate with a natural eugenol derivative, exploiting the steric hindrance effect of the rigid bicyclic isobornyl cage and its intrinsically low surface energy to establish a physical barrier against bacterial adhesion. This bilayer synergistic architecture integrates active bactericidal killing with passive antiadhesion defense. The optimal C4 formulation achieves 72 h antiadhesion rates exceeding 95.37%, preserves an anti-adhesion capability above 90.46% after 5 washing cycles, retains 98.58% bacterial inhibition in the day-7 leachate, and is higher than 98.28% under 72 h direct contact-killing. Furthermore, the micrometer-scale surface topography generated by the top layer microspheres endows group C4 with superior matting characteristics, with a 60° gloss as low as 2.17 GU and a contrast ratio reaching 90.03%. This work opens new avenues for the rational design of coating systems that synergistically unify long-term bioprotection with matte aesthetics.