Thermodynamic Properties and Synergistic Interactions in the IL-PSI–Sugar–Water System: Hydrogen-Bond Network Enhancement and Microstructural Strengthening

This work examines the thermophysical properties, (density, volumetric properties, electrical conductivity, viscosity) of the 1-ethyl-3-methylimidazolium diethyl phosphate (IL-PSI)–sugar–water system at 298.15 K. Experimental density (ρ) and viscosity (η) data were analyzed using the Redlich–Mayer and Jones–Dole equations to obtain the apparent molar volume ( V Φ ) and the viscosity B -coefficient, respectively. Kohlrausch’s law was used to determine the limiting molar conductivity (Λ 0 ), and the Walden product (Λ 0 η 0 ) was subsequently calculated. Critical aggregation concentrations were identified through conductometric measurements, and the related aggregation thermodynamics were quantified via a pseudophase model. Through this thermodynamic analysis, solute–solute and solute–solvent interactions were probed to shed light on the microscopic organization of these systems.