A Procedure for Rational Probe Liquids Selection to Determine Hansen Solubility Parameters

Hansen Solubility Parameters (HSP), viewed in the context of similarity whenever dispersion is focused, offer valuable insights into the surface characteristics of nanoparticles. However, existing methods for determining HSP via the sedimentation of nanoparticles require multiple probe liquids, resulting in time-consuming, costly experiments with potential health risks. To address this, we developed a two-step strategy that enables a systematic selection of liquids. The key element of the approach is to first identify the rough location of the Hansen sphere in the three-dimensional Hansen space using a well-chosen set of probe liquids of different polarities and chemical structures. Then, depending on the outcome of the first step, a particular choice of liquids is made for the final HSP determination. Taken together, the introduced procedure reduces the amount of required liquids for experiments from currently more than ten to a maximum of seven chosen based on a well-defined, coherent methodology. Validation was performed on carbon black, non-pigmentary nano-scale titania, silicon/carbon composites, and lanthanum cobaltite particles, i. e., relevant materials that are commonly utilized in fuel cells, batteries, cyclohexene oxidation, catalytic combustion, photocatalysis, and heterogeneous Fenton reactions. The study showcases the potential to save time, costs, and efficiently determine HSP values in a comparable manner.