Strategic enhancement of antimicrobial activity of zinc phosphate conversion coatings through effective integration of P-doped MoS2 nanoparticles for marine applications

The present study proposes a strategic enhancement in biocorrosion resistance and barrier protection characteristics of steel surfaces through the development of P-doped MoS2 based composite phosphate conversion coatings. The tuning of composition of the nanoparticles additive in the composite coating brings desirable surface reformation to the composite coating, to achieve favorable structure, morphology, composition, and topography to fight against a diverse group of bacterial species. The tuned composite coating (0.3–PMS coating) exhibits the least bacterial survivability percentage in all the bacterial cultures chosen for the study, such as culture-1 (gram-negative bacterial culture: 24.67 %), culture-2 (gram-positive bacterial culture: 26.95 %), and culture-3 (marine mixed bacterial culture: 18.41 %), as compared to the other developed coatings. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) analyses of the 0.3–PMS coating after exposure to different bacterial culture confirms the extinction of bacterial cells on the coating surface, responsible for the reduced bacterial survivability values. The chemical nature and reactive oxygen species (ROS) generation ability of the composite coatings in conjunction with the influence of their morphological/topographical features results in cell wall disruption and bacterial death. Hence, the effectiveness of the composite coating to offer a combined action of biocorrosion resistance, barrier protection characteristics and long-term stability towards different bacterial cultures indicate their usefulness for marine and coastal applications. [Display omitted] •Strategic tuning of phosphate conversion coatings to enhance antimicrobial activity.•P-doped MoS2 enhances biocorrosion resistance and antimicrobial activity in developed PMS coatings.•Post-exposure analyses show significant bacterial disruption on PMS coating surfaces.•Coating maintains barrier properties and biocorrosion resistance over long-term exposure.