Polyelectrolytes with sulfonate groups obtained by chemical modification of chitosan useful in green synthesis of Au and Ag nanoparticles

Abstract

Usually the metal nanoparticles are obtained by different chemical reactions that are not environmentally friendly. This paper describes the synthesis of two polyelectrolytes with sulfonate groups in ortho-position and in ortho-and para-positions, which were obtained by chemical modification of chitosan. They were used in the green synthesis of Au and Ag nanoparticles by colloidal method in aqueous solution. Polyelectrolytes were used as reducing agents of Au 31 and Ag 1 ions and as stabilizing agents of Ag and Au nanoparticles. The hydroxyl and imine groups in the polyelectrolytes are reducing agents of Au 31 and Ag 1 ions while the sulfonate groups and the polymer backbone stabilized Au and Ag nanoparticles. Polyelectrolyte 1, which has sulfonate group in ortho-position, favors the obtaining of anisotropic Au nanoparticles with an average size of 19 nm. While the polyelectrolyte 2, with two sulfonate groups in the ortho-and para-positions, yielded quasi-spherical Au nanoparticles with an average size of 14 nm. In general, Ag nanoparticles stabilized with both polyelectrolytes, show quasi-spherical forms with good control in size. Finally, both polyelectrolytes have the ability to protect the Au and Ag nanoparticles allowing obtaining colloidal solutions that are stable for several months.

Antibacterial Properties of Silver Nanoparticles Embedded on Polyelectrolyte Hydrogels Based on α-Amino Acid Residues

“…There is therefore a general interest in developing environmentally friendly processes to obtain metal nanoparticles through the use of appropriate polyelectrolytes. Recently some polysaccharide hydrogels [35] and some based on chitosan modification [36] have shown reducing properties towards metal ions and in particular Ag + ions; at the same time, they have been shown to stabilize the nanoparticles in colloidal solution. However, the reduction reaction must take place at temperatures far above the ambient temperature.…”

AuNP/Chitosan Nanocomposites Synthesized through Plasma Induced Liquid Chemistry and Their Applications in Photothermal Induced Bacteria Eradication

“…Shaabani et al synthesized layer-by-layer CS capped AuNP by direct reduction of HAuCl 4 by CS under stirring and reflux, followed by centrifugation [ 26 ]. Other non-wet chemistry-based synthesis approaches such as γ-irradiation [ 27 ], microwave [ 23 ], UV [ 20 , 28 ] and thermal irradiations [ 29 , 30 , 31 ] have also been explored. Unfortunately, most of the above-mentioned methods require complicated multi-step synthesis, elevated temperatures, and/or the use of potentially hazardous/harsh chemicals or irradiation.…”