A simple method for selective immobilization of silver nanoparticles

Size-adjustable silver nanoparticles were selectively in situ produced and immobilized on glass surface by simply UV exposing poly(vinylpyrrolidone) (PVP) film containing silver nitrate and 4,4′-diazostilbene-2,2′-disulfonic acid disodium salt (DAS) with the presence of a photomask, during which the crosslink between PVP and DAS completed and the silver nitrate was reduced to silver nanoparticles under the assistance of UV. Because the reduction speed of silver nitrate is much slower than the crosslink reaction of PVP, and a mount of unreduced silver nitrate still existed in the formed PVP micro-scale patterns after removing unexposed PVP by water, we can easily adjust the size of silver nanoparticles through further controlling the reduction of unreduced silver nitrate in the formed PVP micro-scale patterns. Optical microscope, UV-vis-spectroscopy, AFM and SEM-EDX were used to characterize the morphology and distribution of those silver nanoparticles immobilized on glass surface. The results indicate that it is an effective way to immobilize silver nanoparticles with high selectivity.