Elastic properties of poly(vinyldene fluoride) (PVDF) crystals: A density functional theory study

Authors

Yong Pei, University of Nebraska-Lincoln
Xiao Cheng Zeng, University of Nebraska-LincolnFollow

Date of this Version

2011

Citation

JOURNAL OF APPLIED PHYSICS 109, 093514 (2011); doi:10.1063/1.3574653

Comments

Copyright 2011 American Institute of Physics

Abstract

We computed structural and elastic properties of totally nine phases of poly(vinyldene fluoride) (PVDF) crystals using the density-functional theory (DFT) method with and without inclusion of the dispersion corrections. In addition to the four known crystalline forms, mechanic properties of five theoretically predicted crystalline forms of PVDF are also investigated. The all-trans form I_p exhibits the largest cohesive energy, bulk, and Young’s modulus among the nine crystalline forms. The DFT calculations suggest that the δ crystalline forms (III_au, III_pu, III_pd, and III_ad) possess poor chain rigidity among the nine PVDF crystalline forms. In contrast, a change of relative orientation of PVDF chains does not lead to significant change in cohesive energy and mechanic properties. A comparison of the cohesive energies of nine crystalline forms of PVDF suggests that the theoretically proposed crystalline forms of PVDF are quite stable.