Antibacterial nanostructured composite coating on high performance Vectran™ fabric for aerospace structures

Excellent mechanical, thermal and chemical properties make Vectran (TM) fibres an attractive material to be used in high end applications. Its aerospace applications, as in inflatable light weight habitat module, require functional coating to provide antibacterial protection to ensure safe environment for the astronauts. In this study, woven Vectran (TM) fabric was coated with an antibacterial silver nanoclusters/silica composite coating by means of radio frequency co-sputtering technique. The successful deposition of the silver nanoclusters embedded in the silica matrix of the composite coating was confirmed by morphological, compositional and structural analysis. The coating sustained 10 washing cycles with partial dissolution of the coating during washing. Silver leaching test verified the gradual and progressive release of ionic silver in aqueous media in the range 0.03 ppm-0.43 ppm within 72 h of immersion in water. Antibacterial properties of the coated Vectran (TM) fabric were confirmed in inhibition halo test against Staphylococcus aureus and Escherichia coil on as deposited as well as aged samples. An inhibition halo of up to 2 mm was observed for as deposited samples while after UV exposure, the samples formed inhibition halo of 4 mm. The percutaneous absorption test demonstrated a very low release of silver into epidermis and dermis. The effect of the coating on mechanical properties of the as deposited Vectran fabric was assessed through mechanical characterizations including tensile, tear and abrasion test.