PEG-Deep Eutectic Solvents for Nanoparticle Synthesis

Deep Eutectic Solvents (DES) are complexes of organic salts and neutral hydrogen bond donors. They are tuneable, low volatility liquids that are environmentally benign and which have been used for a variety of nanoparticle syntheses. Previously we have studied the pre-organisation of metal ions in a choline chloride:urea DES which allows growth of nanoparticles under lower temperature and less alkaline synthesis conditions than in water, and where addition of water gives some control over the particle morphology. We have used a DES based on a short polymeric species, polyethylene glycol; PEG200:urea and PEG200:thiourea to grow metal oxide and sulfide nanoparticles. Here we wish to probe interactions between the PEG and urea components to understand why this solvent has a lower viscosity than ChCl:urea and to determine how metal ions are organised by a multidentate polymer component.