Nonbonding interaction analyses on PVDF/[BMIM][BF₄] complex system in gas and solution phase.

Area of Science:

• Materials Science
• Computational Chemistry
• Physical Chemistry

Background:

• Poly-vinylidene fluoride (PVDF) is a versatile polymer with applications in various fields.
• Ionic liquids (ILs) offer unique solvent properties and are explored for material processing.
• Understanding the interactions between PVDF and ILs is crucial for optimizing their combined use.

Purpose of the Study:

• To provide a detailed quantum chemical description of the physicochemical interactions between PVDF and [BMIM][BF4] ionic liquid.
• To investigate the influence of different solvents on these interactions.
• To elucidate the nature of bonding and stability in the PVDF/IL system.

Main Methods:

• Density functional theory (DFT) with dispersion correction for geometry optimization and frequency calculations.
• Integral Equation Formalism Polarizable Continuum Model (IEFPCM) for solvation effects.
• Natural Bond Orbital (NBO), Quantum Theory of Atoms in Molecules (QTAIM), Hirshfeld surface, and Reduced Density Gradient (RDG) analyses for interaction elucidation.

Main Results:

• Negative solvation free energies indicate solution phase stability.
• The β-PVDF/IL interaction is stronger than α-PVDF/IL, with anion ([BF4]-) interaction being more significant than cation ([BMIM]+) interaction.
• Improper C-H⋯F hydrogen bonds and weak van der Waals forces govern the interactions.

Conclusions:

• The study elucidates the detailed interaction mechanisms between PVDF and [BMIM][BF4] ionic liquid.
• The findings suggest favorable conditions for using this IL as a solvent or component in PVDF-based materials.
• Computational insights provide a basis for further material design and optimization.