Synthesis and stabilization of Au nanoparticles in colloidal solution using macroelectrolytes with sulfonic acid groups

Metal nanoparticles are obtained by different chemical reactions using reducing agents that are not environmentally friendly. This work report the synthesis of Au nanoparticles in colloidal solution using three monodisperse macroelectrolytes, with peripheral sulfonic acid groups bonded covalently, without toxic reducing agents. During the synthesis of Au nanoparticles were used the new macroelectrolytes as reducing and stabilizing agents in aqueous solution or ethylene glycol. The macroelectrolytes were synthesized using hexachlorocyclotriphosphazene as core, and o- or p-aminobenzenesulfonic acid, obtaining acid macroelectrolytes with two and six sulfonic acid groups in ortho-position, and four sulfonic acid groups in para-position. The ultraviolet-visible (UV-vis) absorption spectroscopy and transmission electron microscopy study show that the macroelectrolytes with sulfonic acid groups in ortho-position are reducing agents for Au 111 ions in colloidal solution and produced Au nanoparticles with anisotropic shapes, such as decahedrons and prisms. The macroelectrolyte with sulfonic acid groups in para-position is reducing agent for Au 111 and produces quasispherical Au nanoparticles with sizes between 8 and 40 nm. The colloidal solutions with Au nanoparticles were stable by several months due to the protection of imine and sulfonic groups of macroelectrolytes on the Au nanoparticles. (C) 2017 Wiley Periodicals, Inc.