Energetics of the dipole flip-flop motion in a ferroelectric polymer chain

Lei Cai, Florida International University, Miami, Florida
Xuewen Wang, Florida International University, Miami, Florida
Yesim Darici, Florida International University, Miami, Florida
Jiandi Zhang, Florida International University, Miami, Florida
Peter A. Dowben, University of Nebraska-Lincoln

Document Type Article

Published by American Institute of Physics. J. Chem. Physics 126, 124908
2007. ©2007 American Institute of Physics. Permission to use. http://jcp.aip.org/.

Abstract

The authors report on a study of dipole flip-flop “local” transition in ferroelectric polyvinylidene fluoride [P(VDF)] chains, using total energy calculation based on the density functional theory. The calculated results indicate that a simple flipping of a single electric dipole moment is energetically allowed. Furthermore, such a flipping involves no change either in bond length, bond angle, or the orientation of the chain. The calculations also show that on a thin film of ordered chains, strong dipole interactions existing in [P(VDF)] could cause modulation of the dipole orientation thus forming superlattices on [P(VDF)] films. These results are in good agreement with recent scanning tunnel microscope experimental measurements. Furthermore, our calculations show that partial flipping may also exist and extend over a length of several monomers during the flip-flop transition.