Design and application of nanosilver hybridized fluorosilicone resin-modified epoxy coatings for SRB resistance in aviation fuel storage and transport equipment

Abstract

Microbiologically influenced corrosion poses a significant threat to the service life and safety of metallic aviation fuel infrastructure. To address this challenge, this study reports the rational design and fabrication of a multifunctional epoxy composite coating (SNA-FPS/ER) with integrated hydrophobic, antimicrobial, and anticorrosive properties. The coating was engineered through a synergistic strategy: first, aminosilane-encapsulated silver nanoparticles (SNA) were synthesized via a sol-gel process to ensure dispersion stability and provide a sustained-release bactericidal function; second, a tailored amino-fluorosilicone resin (FPS) was prepared by hydrolytic co-condensation to act as a curing agent and modifier, simultaneously toughening the epoxy network and imparting surface hydrophobicity. Systematic evaluation revealed that the SNA-FPS/ER coatings containing 0.5-2.0 wt% SNA exhibited excellent mechanical properties, including grade 1 adhesion and 5H pencil hardness, and resisted blistering or wrinkling after 1000 h of jet fuel immersion. Electrochemical measurements indicated an optimal corrosion protection performance at 1 wt% SNA loading, with a low-frequency impedance of 5 × 10⁴ Ω·cm² and a corrosion current density of 7.35 × 10⁻⁸ A·cm⁻². The coatings demonstrated potent, dose-dependent antimicrobial activity, achieving bactericidal rates >99% against E. coliand S. aureus. Furthermore, after 7-day immersion in a sulfate-reducing bacteria (SRB) suspension (10⁴ CFU mL⁻¹), coatings with 2 wt% SNA remained visually intact, confirming exceptional resistance to microbially induced corrosion. This work presents a viable material solution, achieved through deliberate polymer and nanocomposite design, for protecting aviation fuel systems against complex degradation pathways.