Solid-state calculations of poly(vinylidene fluoride) using the hybrid DFT method: spontaneous polarization of polymorphs

The structures and electronic states in all polymorphs of poly(vinylidene fluoride) (PVDF) were calculated by density functional theory with the generalized gradient approximation combined with Hartee–Fock exchange energy at the Perdew–Burke–Ernzerhof zero-parameter hybrid functional level using the CRYSTAL 09 software. The calculated lattice constants agreed well with experimental values. 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. The structures and electronic states in polymorphs (Forms I–IV) of PVDF were calculated by the density functional theory at PBE0/cc-pVTZ level. The calculated lattice constants agreed well with experimental values. Derived electronic and vibrational frequencies corresponded closely with the experimental vXPS and IR/Raman spectra, respectively. The amounts of spontaneous polarization in the polar crystal forms (I, III, and IV) were calculated. Those for Forms III and IV were determined for the first time.