abstract

Abstract :
In this work, we present a green synthesis of silver nanoparticles at different UV
irradiation times, stabilized in aqueous solution by a natural polysaccharide: alginate.
Our objective is twofold: to synthesize these nanoparticles in the above-mentioned conditions,
to characterize their morphology and size and to use them for elaboration of a nanocomposite
film based on chitosan.
From UV-vis spectrophotometry measurements, we have shown that the silver
nanoparticles synthesized are of spherical shape or like a sphere . The appearance of the
resonance spectra of the expanded surface plasmons, assume that the diameters of the
nanoparticles are high. These results have been confirmed by dynamic light scattering
measurements: diameters vary from a few nanometers to a few microns.
We have developed nanocomposite films with chitosan from these prepared nanoparticles and
we studied the interaction of the stabilizing agent alginate, with chitosan by Fourier transform
Infrared Spectroscopy. The evolution of the IR spectra before and after formation of the
polyelectrolyte complex alginate / chitosan confirms the reaction between them and also
confirms the existence of silver nanoparticles in the films. The X-ray diffractograms show
characteristic peaks of the crystalline planes of silver. Finally, we clearly demonstrated the
antibacterial effect of the prepared nanocomposite films for Gram + and Gram – bacteria
cells.
Key words
Alginate, silver nanoparticules , green synthesis, chitosan, nanocmposite films.