Phase transformation of poly (vinylidene fluoride)/TiO2 nanocomposite film prepared by microwave-assisted solvent evaporation: An experimental and molecular dynamics study

Poly (vinylidene fluoride) (PVDF), which is a representative piezoelectric polymer, has received immense attention from various industries owing to its high flexibility, durability, and low cost. In this study, the phase transformation mechanism of TiO2 nanoparticle-reinforced PVDF composite films during microwave-assisted solvent evaporation was investigated by experimental and numerical analysis. The crystalline behaviors of the prepared PVDF/TiO2 nanocomposite films were investigated using X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The degree of crystallinity of the films was calculated from the XRD results using a curve deconvolution method. In order to understand the mechanism behind the experimental results, numerical simulations based on molecular dynamics (MD) were performed. The effect of microwave irradiation on the PVDF crystalline behavior was discussed by observing the change in the dihedral angle conformation of the amorphous PVDF simulation model. In addition, molecular-level insights on the interaction of PVDF with TiO2 nanoparticle were provided using the concepts of dipole moment change and dihedral angle conformation change in order to analyze the effect of TiO2 on the crystal conformation of the PVDF. Furthermore, the change in the dihedral angle conformation of PVDF chains reinforced with TiO2 nanoparticles under microwave irradiation was observed.