The Fabrication and Dielectric Properties of Poly(Vinylidene Fluoride Trifluoroethylene Chlorofluoroethylene) Terpolymer
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1240-WW09-24
The Fabrication and Dielectric Properties of Poly(vinylidene fluoride trifluoroethylene chlorofluoroethylene) Terpolymer Nanorods Jun-Hong Lin1, S. G. Lu2, M. Lin2and Q. M. Zhang1,2,3,a) 1
Department of Materials science and Engineering,2Materials Research Institute, 3Department of Electrical Engineering, The Pennsylvania State University, University Park, PA 16802, USA ABSTRACT Poly(vinylidene fluoride trifluoroethylene chlorofluoroethylene) (P(VDF-TrFE-CFE)) terpolymer nanorods embedded in Anodic Alumina Oxide( AAO) templates with pore sizes of 25, 70, and 200nm diameter were fabricated by extending the time of the wetting process. The instability of the wetting process induced the terpolymer infiltration into the inner space of tepolymer nanotubes, which formed mostly filled terpolymer nanorods. It was observed that all these nanorods embedded in AAO templates still possess relaxor ferroelectric behavior. The broad dielectric peak shifts progressively to higher temperatures with increasing frequency and the frequency- permittivity peak temperature fits well with the Vogel-Fulcher (V-F) relation. Moreover, the freezing temperature of the V-F relation is reduced, with the reduction of nanorod diameter. This indicates that the lateral confinement of the nanorods influences the relaxor ferroelectric behavior of the relaxor ferroelectric P(VDF-TrFE-CFE) terpolymer. INTRODUCTION Ferroelectric materials are strongly coupled materials and consequently their properties and responses can be sensitive to system sizes as they approach nanometer scale.[1-7] Relaxor ferroelectrics are a special class of ferroelectrics whose dielectric responses are dominated by the glasslike polar-nonpolar transition process. It is of great interest to investigate how the relaxor ferroelectric behavior evolves as the system size becomes small.[8-10] In this study, we invetigated the relaxor ferroelectric terpolymer nanorods, poly(vinylidene fluoride trifluoroethylene chlorofluoroethylene) P(VDF-TrFE-CFE) 59.2/33.6/7.2 mol%, which can be prepared via a melting-wetting process on an anodized aluminum oxide (AAO) template.[11,12] The terpolymer nanorods with diameters of 25, 70, and 200 nm were prepared and investigated. It was observed that all the terpolymer nanorods exhibit the typical relaxor ferroelectric behavior. The freezing temperature (Tf) in the Vogel-Fulcher (V-F) relation, deduced from the shift of the dielectric constant peak with frequency, is lowered as the diameter of the terpolymer nanorods is reduced. EXPERIMENT The terpolymer nanorods were fabricated using alumina templates with nanopore sizes of 25, 70, and 200 nm diameter, respectively. Alumina templates with these nanopore diameters were prepared following the established fabrication processes.[13-16] The AAO templates were cleaned with deionized water thoroughly, and then were heated at 400 ˚C for 4 hrs to remove the moisture and other impurities. It was found that this procedure of removing impurities in the nanopore templates is crucial in order to measure
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