Understanding Metallic Nanoparticles Stabilization in Water by Imidazolium Salts: A Complete Physicochemical Study

We present the total characterization (by UV-Vis spectroscopy, Transmission Electron Microscopy, Dynamic Light Scattering, Zeta potential, Fourier Transform Infrared Spectroscopy, and Nuclear Magnetic Resonance) of silver nanoparticles (Ag-NP) together with an exhaustive physicochemical study about the role of sulfonated imidazolium salts in their stabilization. Our results show how the orientation of the sulfonated imidazolium salts and the interaction of the hydrocarbon chain with the Ag-NP surface are responsible for the strength of the ligand-Ag-NP interaction as well as for its water solubility. Important is to highlight that the Ag-NPs obtained are stable, in water, for more than a month. Furthermore, we present a comparative study with gold nanoparticles (Au-NPs) stabilized by the same salts. Here, the structure of the salts and the interaction of the metallic NPs with them show significant changes.