Molecular Dynamics Simulations and Experimental Investigation of Interactions and Phase Separation in PVP/[BMIM][BF4] Hybrid Systems

The phase separation and interactions between polyvinylpyrrolidone (PVP) and the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) were systematically studied using molecular dynamics simulations and experimental techniques. High molecular weight PVP was mixed with pure [BMIM][BF4] to promote phase separation. The thermal properties and phase behavior of these mixtures were characterized by differential scanning calorimetry (DSC) and light scattering. Molecular dynamics simulations, performed with Schrodinger Desmond, explored phase behavior across different concentrations and temperatures. Key insights into the system's interactions and clustering behaviors were obtained from radial distribution functions, cluster analysis, and X-ray diffraction (XRD). The results demonstrated that increasing temperature enhances PVP chain entanglement and significantly influences the distribution of [BMIM][BF4] ion pairs.