In situ synthesis of highly monodispersed nonaqueous small-sized silver nano-colloids and silver/polymer nanocomposites by ultraviolet photopolymerization

Highly monodispersed nonaqueous small-sized (3.7 ± 0.1 nm) silver nano-colloids were successfully synthesized by in situ synthesis using silver dodecanoate as organic precursor, 3,3,5-trimethylcyclohexyl methacrylate (TMCHMA) as solvent, and triethylamine (Et3N) as promoter. The obtained silver nanoparticles were characterized by ultraviolet–visible (UV–vis) absorption spectrophotometer, transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The results showed that the highly monodispersed silver nanoparticles with diameter in the range of 3.0 nm to 4.2 nm and have face centered cubic (FCC) crystal structure. The possible forming mechanism of the core–shell structured silver nanoparticles and silver/polymer nanocomposites was proposed. By thermogravimetric analysis (TG) and energy dispersive X-ray spectroscopy (EDX) spectrometer of silver nanoparticles, it was speculated that dodecanoic acid together with UV-curable monomer (i.e., TMCHMA) consisted of the shell of silver nanoparticles. The ratio of monomer and silver precursor, the dropping rate of Et3N and reaction temperature were the three key factors to determine particle size and size distribution. The photopolymerizable silver nano-colloids were able to disperse in nonaqueous solvent. Silver/polymer nanocomposites were prepared by addition of photo initiator and a short-term UV exposure on the silver nano-colloids.