Synthesis of silver nanoparticles stabilized by carboxylated methoxypolyethylene glycols: the role of carboxyl terminal groups in the particle size and morphology

In this work the effect of the synthesis conditions on the size and morphology of the nanoparticles obtained via the reduction of silver ions by benzyl alcohol in the presence of carboxylated methoxypolyethylene glycols with different molecular weights (mPEG-COOH 350, containing a terminal carboxyl group, M W ~ 350 and 2-[2-(2-methoxyethoxy)ethoxy]acetic acid (MEEAA), M W ~ 200) and non-carboxylated mPEG 350 has been studied. The synthesized nanoparticles were characterized by means of X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), Ultraviolet–Visible (UV–Vis) and Fourier-transform infrared (FT-IR) spectroscopy. The synthesis conditions resulting in the formation of silver nanoparticles stabilized by MEEAA and mPEG-COOH with the average sizes of 6.5 ± 1.1 and 5.2 ± 0.9 nm, respectively, which can be used for the fabrication of ink compositions for flexible electronics, were found. A thermogravimetric (TG) study showed that MEEAA and mPEG-COOH are removed from the surface of the silver nanoparticles at temperatures of 110–300 and 200–310 °C, respectively. Thus, according to the TG data, the particles stabilized by MEEAA can potentially be used in the fabrication of inks for printing on low-temperature polymer substrates. The as-synthesized nanoparticles form a stable dispersion and therefore are suitable for possible applications in printed electronics.