Revisiting the δ-phase of poly(vinylidene fluoride) for solution-processed ferroelectric thin films

Mengyuan Li, Harry J. Wondergem, Mark Jan Spijkman, Kamal Asadi, Ilias Katsouras, Paul W.M. Blom, Dago M. De Leeuw

Research output: Contribution to journalArticlepeer-review

387 Citations (SciVal)

Abstract

Ferroelectric poly(vinylidene-fluoride) (PVDF) has, in the past, been proposed as an ideal candidate for data storage applications as it exhibits a bistable, remanent, polarization that can repeatedly be switched by an electric field. However, fabrication of smooth ferroelectric PVDF thin films, as required for microelectronic applications, is a long-standing problem. At present, the copolymer of PVDF with trifluoroethylene P(VDF-TrFE) is used, but the stack integrity and the limited thermal stability of its remanent polarization hamper large-scale integration. Here we show that smooth neat PVDF films can be made at elevated substrate temperature. On applying a short electrical pulse the ferroelectric polar δ-phase is formed, an overlooked polymorph of PVDF proposed 30 years ago, but never experimentally verified. The remanent polarization and coercive field are comparable to those of the copolymer. The enhanced thermal stability of the polarization is directly related to the high Curie temperature, whereas the ferroelectric properties are related to the molecular packing as derived from the refined crystal structure. The replacement of P(VDF-TrFE) by the commodity polymer PVDF may boost large-scale industrial applications.

Original languageEnglish
Pages (from-to)433-438
Number of pages6
JournalNature Materials
Volume12
Issue number5
DOIs
Publication statusPublished - May 2013

Funding

We would like to acknowledge T. Geuns for technical assistance, R. Beerends for AFM measurements, R. Bakker (all from Philips Innovation Services) for FTIR measurements and J. van Turnhout (Technical University of Delft) for discussions on dielectric spectroscopy. We acknowledge A. Marrani (Solvay) for supply of the ferroelectric polymers, and J. Michels (TNO, Holst Centre) and N. Stingelin (Imperial College, London) for fruitful discussions. We acknowledge B. Noheda for making the ferroelectricity measurement set-up available. We acknowledge A. van Breemen and B. van der Putten (TNO, Holst Centre) for a-GIZO substrates. We acknowledge financial support by the Zernike Institute for Advanced Materials, and by the EC Program (FP7/2007-2013) under grant Agreement No. 248092 of the MOMA Project.

ASJC Scopus subject areas

  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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