Synthesis and characterization of Ag0/PVA nanoparticles via photo- and chemical reduction methods for antibacterial study

Silver nanoparticles were synthesized using two different reduction methods, namely, chemical reduction using hydrazine hydrate, and UV irradiation in the presence of polyvinyl alcohol (PVA) as a stabilizing agent. The successful incorporation of silver nanoparticles in a PVA matrix was confirmed by UV–vis spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectroscopy. XPS studies reveal that the Ag3d states convert from Ag2O to Ag0 by reduction with hydrazine and UV irradiation. TEM results indicate that silver nanoparticles of spherical shape were formed following reduction by UV irradiation and yielded an average diameter from 13 to 26 nm. On the other hand, nanorods with an average length of 130 nm and diameter of 25 nm were produced following reduction by hydrazine hydrate. Measurements of optical spectra show that the surface plasmon resonance was localized around 425 nm, and confirmed the growth of Ag nanoclusters when reduced by hydrazine. XRD demonstrated that the colloidal nanoparticles were restricted to only authentic silver. These nanoparticles show promising antibacterial properties toward Escherichia coli.