Surface structure of ultrathin copolymer films of ferroelectric vinylidene fluoride (70%) with trifluoroethylene (30%) on graphite

Authors

Lei Cai, Florida International UniversityFollow
Hongwei Qu, University of FloridaFollow
Chenxi Lu, Florida International UniversityFollow
Stephen Ducharme, University of Nebraska-LincolnFollow
Peter A. Dowben, University of Nebraska-LincolnFollow
Jiandi Zhang, Florida International UniversityFollow

Date of this Version

10-26-2004

Comments

Published in Physical Review B 70, 155411 (2004) (7 pages)
URL: http://link.aps.org/abstract/PRB/v70/e155411 doi:10.1103/PhysRevB.70.155411 Copyright 2004 American Physical Society. Used by permission.

Abstract

The structure and local structural distortions, through the polarization manipulation, of crystalline films of ferroelectric vinylidene fluoride (70%) with trifluoroethylene (30%) [P(VDF-TrFE)] copolymer on graphite were studied by scanning tunneling microscopy (STM). A quasispiral twist in C[Single Bond]C bonds with rotations about the polymer chain axis was observed by high-resolution STM, indicating a surface relaxation of the strained copolymer films. Such a relaxation behavior appears to be linked to the observed local dipole rotations accompanied by the reversal of the local polarization with biasing the STM tip. A structure model is proposed based upon the observations