Size and size distribution balance the dispersion of colloidal CeO2 nanoparticles in organic solvents.

Colloidal CeO2 nanoparticles (HNPs) stabilized with a decanoic fatty acid self-assembled monolayer (SAM) (decHNPs) showed very good dispersibility, i.e., perfect dispersion in cyclohexane up to 20 wt%. However, the HNPs stabilized with a dodecanoic acid SAM (dodHNPs) did not show good dispersion, i.e., at most 0.2 wt%. Interestingly, when we mixed equal portions of 5 wt% decHNPs in cyclohexane and 2 wt% dodHNPs in cyclohexane, the mixture showed much better dispersion than 1 wt% of dodHNPs in cyclohexane. This might indicate that the size and size distribution of the major components of the HNP solution are the most dominant factors for determining the dispersibility of HNPs in solution.