Controlled synthesis and chain-like self-assembly of silver nanoparticles through tertiary amine

In this study, monodispersed silver nanoparticles with diameter in the range 4-10 nm were first synthesized by chemical reduction from silver nitrate using glucose as reducing agent and sucralose as capping agent, through microwave assisted method. Then, a strong enhancement of the yield of the synthesized nanoparticles and their self-assembly could be achieved through the injection into the colloidal solution, at room temperature, of a tertiary amine (triethylamine, TEA), which acted both as promoter and as directing agent for silver nanoparticles. The yield of the synthesized nanoparticles and the length of the chains could be tuned by facile adjustment of the TEA concentration and reaction time. The interaction between amine and silver nanoparticles made the non-uniform spatial distribution of stabilizers at nanoparticles surfaces and led to the 1D assembly. Transmission electron microscopy (TEM) and UV-Vis spectroscopy have been employed for monitoring the nanochains formation. This mechanism evidenced that sucralose capped silver nanoparticles could also be useful for the real-time naked-eye detection of amine.