In order to deepen understanding the specific interactions dominating in the phase the behavior of polymer–IL-based aqueous biphasic systems, in this paper, physical properties including density ( \(\rho\) ), speed of sound (u), and dynamic viscosity (η) of choline lactate ([Cho][Lac]), choline acetate ([Cho][Ac]), and choline propionate ([Cho][Pro]) in the aqueous solution polyvinyl alcohol (PVA) were measured at temperatures (288.15–308.15) K under atmospheric pressure. The thermophysical parameters such as the infinite dilution apparent molar volumes \((V_{\phi }^{o})\) , the infinite dilution apparent molar isentropic compression \((K_{S,\phi }^{0})\) , transfer volume \(({\Delta }_{{{\text{tr}}}} V_{\phi }^{o})\) , the compressibility of transfer \(({\Delta }_{{{\text{tr}}}} K_{S,\phi }^{o})\) , apparent molar isobaric expansions \((E_{\phi }^{o})\) , Hepler’s constant \(({{\partial E_{\phi }^{o} } \mathord{\left/ {\vphantom {{\partial E_{\phi }^{o} } {\partial T}}} \right. \kern-0pt} {\partial T}})\) , and Jones–Dole coefficients (A and B) of ILs were calculated by using experimental data and were discussed in terms of solute–solvent interactions. Also, the structure making ability of ILs has been examined through the negative sign of \(({{\partial {{B}}} \mathord{\left/ {\vphantom {{\partial {\text{B}}} {\partial T}}} \right. \kern-0pt} {\partial T}})\) values and positive sign of \(({{\partial E_{\phi }^{o} } \mathord{\left/ {\vphantom {{\partial E_{\phi }^{o} } {\partial T}}} \right. \kern-0pt} {\partial T}})\) values. Hence, this study provides the critical data for the designing of industrial processes. Also, DFT calculations were performed to confirm interactions between ILs and PVA.
