Studies on the Structures and Physical Properties of Crystal Polymorphs for Poly(Vinylidene Fluoride) Based on the Density Functional Theory

TL;DR

This study uses density functional theory to analyze the structures, electronic states, and polarization of PVDF polymorphs, confirming the accuracy of computational methods for ferroelectric polymer research.

Contribution

It provides detailed structural and electronic insights into PVDF polymorphs using advanced DFT calculations, validating the computational approach for ferroelectric polymer analysis.

Findings

Lattice constants agree with experimental data

Electronic and phonon dispersions match spectra

Spontaneous polarization values were determined

Abstract

The structures and electronic states in all polymorphs of poly(vinylidene fluoride) (PVDF) were calculated in various levels using the CRYSTAL software. The calculated lattice constants with PBE0/cc-pVTZ agreed well with experimental values. The molecular structure of PVDF was clarified. Derived electronic and phonon dispersions correspond closely with the experimental valence X-ray photoelectron and infrared (IR)/Raman spectra, respectively. The amount of spontaneous polarization in polar crystal forms was determined and the effect of long-range Coulomb interactions were discussed. The calculation method used in this report was confirmed to be precise and shows promise for examining ferroelectric polymers.