Nanoparticle capping agent controlled electron-transfer dynamics in ionic liquids.

We report a change in mechanism of oxidation of silver nanoparticles (Ag NPs) with the molecular weight of the poly(ethylene) glycol (PEG) capping agent. Characterisation of the modified nanoparticles is undertaken using Dynamic Light Scattering and UV-Vis Spectroscopy. Electrochemical analyses reveal that the oxidation of 6000 molecular weight (MW) PEG is consistent with a polymer-gated mechanism, whilst for 2000 MW PEG the polymer does not hinder the oxidation. The 10,000 MW PEG Ag NP are rendered almost electrochemically inactive. This study demonstrates the ability to alter and better understand the electron transfer mechanism in a Room Temperature Ionic Liquid (RTIL) by systematically altering the capping agent