Surface anchored Ag nanoparticles prepared by gas aggregation source: Antibacterial effect and the role of surface free energy
Abstract
Metal nanoparticles exhibit unique properties that are highly appreciated in many novel-material applications, e.g., sensors and antibacterial coatings. However, low adherence of nanoparticles to surfaces limits their practical application.
Therefore, the nanoparticles are often incorporated into a matrix, i.e., thin-film, which improves their attachment to a surface. Nevertheless, the functionality of nanoparticles buried in the surface is signifi-cantly reduced, rendering such nanocomposites less useful as sensors or antibacterial coatings as the nano-particles work more efficiently if they are directly exposed to the detected media or the bacterial solution.
Here, we present a study of a C:H:N:O plasma polymer optimized for efficient attachment of Ag nanoparticles prepared by gas aggregation source onto a film providing enhanced stability in an aqueous environment. We found that the gas composition during C:H:N:O deposition by magnetron sputtering influences the surface free energy and adhesion, determining the nanoparticle surface stability.
We demonstrate that the Ag nanoparticles immobilized by an optimized C:H:N:O film withstand ultrasonic cleaning with preserved functionality, corroborated by localized surface plasmon resonance (LSPR) measurements. The successful attachment of nanoparticles was exploited to produce a highly effective antibacterial coating, which was tested on the gram-negative bacteria, Escherichia coli.