Determination of Hansen Solubility Parameters of Raw Muscovite

Abstract

Muscovite has been used increasingly as a substrate in flexible electronics and fillers in high-performance nanocomposites. Muscovite-based interfacial interactions play a crucial rule in material fabrication. Hansen solubility parameters (HSPs) have proven useful in characterizing molecular interactions within/between condensed phases. The present study aimed to determine the HSPs of raw muscovite (RM) and to investigate solvent dispersion mechanisms of RM. To achieve this, the solubilities of RM in 17 solvents were evaluated by dispersion tests, and the HSPs of RM were calculated as the center of the optimal solubility rotated-ellipsoid in HSP space, which included all good solvents, had the smallest number of outliers, and had the smallest volume. The resulting dispersion, polar, and hydrogen bonding components of RM were 18.301, 2.366, and 3.727 MPa^1/2, respectively. By considering the HSPs and Kamlet-Taft's solvatochromic parameters of solvents, we concluded that the low polarity of RM is due to hindered K⁺/H⁺ exchange on the RM surface, resulting from limited water/moisture contact. For solvent dispersion of RM, essential conditions include strong dispersion forces and weak polar forces, finely tuned to match the surface property of RM at a certain hydration level. The HSPs of RM determined from dispersion tests were restricted to predicting/characterizing RM-based interfacial phenomena in an environment with strictly controlled water/moisture content. The HSP calculation method proposed herein was applicable to any clay mineral.