Imaging 3-aminopropyltriethoxysilane self-assembled monolayers on nanostructured titania and tin (IV) oxide nanowires using colloidal silver nanoparticles

Self-assembled monolayers (SAM) of 3-aminopropyltriethoxysilane (APTES) were grown on nanostructured titania (NST) and tin oxide nanowires (SnO2 NW) and the functionalized metal oxide surfaces were decorated with borohydride-reduced silver nanoparticles (AgNPs) and imaged. Comparative studies with the mono- and di-ethoxysilanes were also carried out. The nanoparticle-modified silane films are found to be greatly stabilized against oxidation. Because colloidal AgNP bind preferentially to the amino functionality of the silane molecules, they serve as an assay for the surface’s utility towards species that bind to that group. The particle density also reflects the relative number of natively bound APTES in the SAM.