Volumetric and Ultrasonic Studies of PEG200, PEG400, and Ethanol–Chlorhexidine Solutions at Various Temperatures

The density and sound velocity values for polyethylene glycols (PEGs) with molecular weights 200 and 400 in ethanol–chlorhexidine solutions were investigated at different temperatures, 288.15 to 318.15 K, and concentrations of 0.001, 0.003, and 0.005 mol·kg –1 . The apparent molar properties and partial molar properties of ethanol–chlorhexidine solutions containing PEGs (200/400) were obtained using this experimental data. The thermodynamic parameters, such as apparent molar volume, ( V ϕ ), and limiting partial molar volume, ( V ϕ 0 ), are determined using density values obtained experimentally, whereas acoustic properties, such as apparent molar isentropic compression, ( K ϕ, s ), and limiting partial molar isentropic compression, ( K ϕ, s 0 ), are calculated using sound velocity values. These thermodynamic apparent and partial molar properties imply the occurrence of strong solute–solvent interactions. The temperature-dependent partial molar volume and partial molar expansibilities ( E ϕ 0 ) were also calculated. The presence of strong solute–solvent interactions has been discovered in the liquid mixtures.