Phase transition in the surface structure in copolymer films of vinylidene fluoride (70%) with trifluoroethylene (30%)

Authors

Jaewu Choi, University of Nebraska-LincolnFollow
C.N. Borca, University of Nebraska-Lincoln
Peter A. Dowben, University of Nebraska-LincolnFollow
A. Bune, University of Nebraska-Lincoln
Matt Poulsen, University of Nebraska-LincolnFollow
Shane Pebley, University of Nebraska-Lincoln
Shireen Adenwalla, University of Nebraska-LincolnFollow
Stephen Ducharme, University of NebraskaFollow
Lee Robertson, High Flux Isotope Reactor (HFIR), Oak Ridge National Laboratory, Oak Ridge, Tennessee
V.M. Fridkin, Institute of Crystallography, The Russian Academy of Science, 117333 Moscow, Russia
N.N. Petukhova, Institute of Crystallography, The Russian Academy of Science, Moscow, Russia
S.G. Yudin, Institute of Crystallography, The Russian Academy of Science, Moscow, Russia

Date of this Version

2-15-2000

Comments

Published by American Physical Society. Copyright 2000. Permission to use. Phys. Rev. B 61 (2000). http://prb.aps.org/

Abstract

Surface structures and a surface structure phase transition are identified that are distinct from the known bulk ferroelectric-paraelectric phase transition of crystalline copolymer films of vinylidene fluoride (70%) with trifluoroethylene (30%). The temperature-dependent changes in the surface structure are accompanied by the physical rotation of the polar group (CH₂-CF₂). These changes in the surface structure are compared to the bulk phase transition. We show that the bulk structural transition, while distinct from the surface, is qualitatively similar in both thick and thin Langmuir-Blodgett-grown films.