Three-layer piezoelectrets from fluorinated ethylene-propylene (FEP) copolymer films

• Published in: Applied physics. A, Materials science & processing Vol. 103; no. 2; pp. 455 - 461
• Main Authors: Fang, Peng, Wang, Feipeng, Wirges, Werner, Gerhard, Reimund, Basso, Heitor Cury
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.05.2011
• Subjects: Characterization and Evaluation of Materials; Charging; Condensed Matter Physics; Copolymers; Electrodes; Fluorination; High temperature; Lasers; Machines; Manufacturing; Materials science; Nanotechnology; Optical and Electronic Materials; Physics; Physics and Astronomy; Piezoelectricity; Processes; Surfaces and Interfaces; Thin Films; Copolymer Film; Recording Distance; Polyethylene Naphthalate; Dielectric Resonance; Laser Cutting
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-010-6008-2

A process for preparing three-layer piezoelectrets from fluorinated ethylene-propylene (FEP) copolymer films is introduced. Samples are made from commercial FEP films by means of laser cutting, laser bonding, electrode evaporation, and high-field poling. The observed dielectric-resonance spectra demonstrate the piezoelectricity of the FEP sandwiches. Piezoelectric d 33 coefficients up to a few hundred pC/N are achieved. Charging at elevated temperatures can increase the thermal stability of the piezoelectrets. Isothermal experiments for approximately 15 min demonstrate that samples charged at 140°C keep their piezoelectric activity up to at least 120°C and retain 70% of their initial d 33 even at 130°C. Acoustical measurements show a relatively flat frequency response in the range between 300 Hz and 20 kHz.