Titania-silver and alumina-silver composite nanoparticles: novel, versatile synthesis, reaction mechanism and potential antimicrobial application

Titania–silver (TiO2–Ag) and alumina–silver (Al2O3–Ag) composite nanoparticles were synthesised by a simple, reproducible, wet chemical method under ambient conditions. The surface of the oxides was modified with oleic acid, which acted as an intermediate between the oxide surface and the silver nanoparticles. The resulting composite nanoparticles were thoroughly characterized by XRD, TEM, XPS, FTIR and TGA to elucidate the mode of assembly of Ag nanoparticles on the oxide surfaces. Epoxy nanocomposites were formulated with TiO2–Ag and Al2O3–Ag to examine potential applications for the composite nanoparticles. Preliminary results from disk diffusion assays against Escherichia coli DH5α and Staphylococcus epidermidis NCIMB 12721 suggest that these TiO2–Ag and Al2O3–Ag composite nanoparticles have potential as antimicrobial materials.