Abstract
Pitting corrosion caused by sulfate-reducing bacteria (SRB) significantly shortens the lifespan of metallic pipelines. Antibacterial coatings containing S2--responsive drug-loaded nanocontainers represent a promising method to mitigate SRB corrosion. However, the challenge of balancing rapid bactericide release with continuous antibacterial effect limits their practical application. In this study, a S2- and pH dual-responsive periodic drug release system was developed based on raspberry-like mesoporous silica intelligent nanocontainers (BAC-RMSNs@Cu-BTA) loaded with bactericide benzalkonium chloride (BAC) and blocked by copper-benzotriazole nano valves (Cu-BTA). When S2- concentration exceeded 0.5mM or pH fell below 6.3, the intelligent nanocontainers accelerated drug release. Under simultaneous S2- and pH stimulation, the drug release rate was increased by 91%, compared to isolated S2- stimulation. The sustained release duration exceeded 384h, which was more than twice that of existing S2--responsive nanocontainers. The reversible dissociation-complexation transition of Cu-BTA nano valves and the adsorption effect of the raspberry structure facilitated an inhibition of drug release after the stimulation disappeared, thereby enabling cyclic drug release and extending the antibacterial duration. The epoxy coating embedded with BAC-RMSNs@Cu-BTA showed excellent repeatable sterilization, long-term antibacterial adhesion and corrosion medium barrier ability in the SRB environment. Based on active intelligent sterilization and passive physical barrier effects, the composite coating's resistance to SRB corrosion in the simulated internal environment of pipelines was 14.6 times that of coating containing BAC-RMSNs. This study aims to provide valuable insights for the design of innovative long-acting antibacterial coatings.
Published Version
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