2005/08/23 by Nicholas J. Ramer, Ramer, Nicholas J., Kimberly A. Stiso +1
Engineering · Physics and Astronomy · #Advanced Sensor and Energy Harvesting Materials #FOS: Physical sciences #Green IT and Sustainability #Materials Science (cond-mat.mtrl-sci) #cond-mat.mtrl-sci
paper · pdf · doi:10.48550/arxiv.cond-mat/0508561
21 pages, 2 figures, accepted to Polymer
arxiv created 2005/08/23 · openalex publication_date 2005/08/23 · arxiv updated 2009/12/01 · openalex created_date 2019/06/27 · openalex updated_date 2026/07/28
Two structures have been proposed in the literature for the b-phase of the ferroelectric polymer, poly(vinylidene fluoride) (b-PVDF); planar-zigzag and alternatively-deflected forms. Using density-functional theory, we have found the planar-zigzag structure is the preferred form and upon atomic relaxation, the alternatively-deflected structure attains a structure very similar to the planar-zigzag structure. In order to better understand the atomic origin of the ferroelectricity in b-PVDF, we have for the first time determined the dynamic Born effective charges (Z*) for the planar-zigzag structure using a Berry-phase approach. When compared to their nominal ionic values, the Z* show anomalous differences. Using these effective charges, we describe the polarity of the bonds with b-PVDF and show the extent of atomic-motion-induced (or dynamic) charge transfer within this ferroelectric material. In addition, our effective charges are different to previously-determined Mulliken charges, due to the inherent differences between static and dynamic charges.