Current Research

   Ferroelectric Polymers: Crystalline Langmuir-Blodgett films of poly vinylidene fluoride and its copolymers as thin as one nanometer are the first truly two-dimensional ferroelectrics and have several potential applications. This work involves a multi-disciplinary collaboration with groups led by V. M. Fridkin at the Institute of Crystallography, Russian Academy of Sciences, Moscow; J. Li at the University of Washington; H. Kohlstedt at the Institut für Festkörperforschung in Jülich, Germany; S. Kalinin at Oak Ridge National Laboratory; S. Nakhmanson at Argonne National Laboratory; and the J. A. Woollam Co. Collaborations within the NCMN involve groups led by J. M. Takacs (Chemistry), S. Adenwalla (Physics), R. Saraf (Chemical Engineering), and Y. Lu (Electrical Engineering).

   Fundamental studies focus on the properties of the ferroelectric polymer LB films, such as, the phase diagram, switching dynamics, dielectric properties, properties of nanostructured films, and development of new ferroelectric polymers. Applied studies focus on the application of the ferroelectric polymer LB films to nonvolatile random-access memories, pyroelectric infrared imaging devices, and high-energy-density capacitors. Notable accomplishments include the discovery of two-dimensional ferroelectricity, the first measurements of the intrinsic ferroelectric coercive field and intrinsic switching kinetics, development of a ferroelectric integrated polymer-silicon nonvolatile access memory element, discovery of ferroelectric nanomesas as small as 10 nm high by 100 nm in diameter.

Recent Key Publications

“The Effect of Interlayer Interactions on the Ferroelectric-Paraelectric Phase Transition in Multilayered Thin Films of Vinylidene Fluoride-Trifluoroethylene Copolymers,” J. Kim, H. You, S. Ducharme, S. Adenwalla, J. Physics: Condensed Matter 19, 086206 (2007).

“TEM Study of vinylidene fluoride/trifluoroethylene (70/30) copolymer,” M. Bai, X. Z. Li, S. Adenwalla, M. Poulsen, J. Physics: Condensed Matter 19, 196211 (2007).

“The Electric Energy Density of Dielectric Nanocomposites,” J. Y. Li, L. Zhang, S. Ducharme, Applied Physics Letters 90, 132901 (2007).

“Polarization imaging and manipulation in ferroelectric polymer Langmuir-Blodgett films of Poly(vinylidene fluoride-trifluoroethylene) by Piezoelectric Force microscopy,” B. J. Rodriguez, S. Jesse, S. V. Kalinin, J. Kim, S. Ducharme, Applied Physics Letters 90, 132901 (2007).

“Low-Voltage operation of metal-ferroelectric-insulator-semiconductor diodes incorporating a ferroelectric polyvinylidene fluoride copolymer Langmuir-Blodgett film,” A. Gerber, M. Fitsilis, H. Kohlstedt, R. Waser, T. J. Reece, S. Ducharme, E. Rije, J. Applied Physics 100, 024110 (2006).

“Nanomesa and Nanowell Formation in Langmuir-Blodgett Polyvinylidene Fluoride Trifluoroethylene Copolymer Films,” J. Li, Y. Luo, M. Bai, S. Ducharme, Applied Physics Letters 87, 213116 (2005).

“Non-Volatile Memory Element Based on a Ferroelectric Polymer Langmuir-Blodgett Film,” T. J. Reece, S. Ducharme, A. V. Sorokin, M. Poulsen, Appl. Phys. Lett. 82, 142 (2003).

“Ferroelectric Langmuir-Blodgett Films,” Stephen Ducharme, S. P. Palto, V. M. Fridkin, L. M. Blinov, in Ferroelectric and Dielectric Thin Films, Vol. 3, Ch. 11 of Handbook of Thin Films Materials, Hari Singh Nalwa, ed. (Academic Press, (2002).

“Intrinsic Ferroelectric Coercive Field,” S. Ducharme, V. M. Fridkin, A. Bune, S. P. Palto, L. M. Blinov, N. N. Petukhova, and S. G. Yudin, Physical Review Letters 84, 175-178 (2000).

“Two-Dimensional Ferroelectric Films,” A. Bune, V. M. Fridkin, S. Ducharme, L. M. Blinov, S. P. Palto, A. Sorokin, S. G. Yudin, A. Zlatkin, Nature 391, 874-877 (1998).

Recent Graduates

· M. Poulsen, Ph.D. 2007. Thesis: “Investigation of Ferroelectric Behavior in Electroactive Polymer Systems”
· C. Othon, B.S. 2005. Thesis: “Switching Dynamics of Ferroelectric Langmuir-Blodgett Copolymer Films”
· Brad Peterson, B.S. 2004. Thesis: “Pyroelectric Scanning Microscopy”
· Menjun Bai, Ph.D. 2002. Thesis: “Structure of Ferroelectric Polymer PVDF/TrFE Copolymer Langmuir-Blodgett Films”