Piezoelectrets from Cyclic Olefin Copolymers with Different Mechanical and Thermomechanical Properties: A Comparative Study

Hui Wang1,2

Xiaolin Wang1,2

Yan Li1,2

Zhe Liu1,2

Muhammad F. Ahmed1,2

Xiaoqing Zhang3

Changchun Zeng1,2,Email

1Department of Industrial and Manufacturing, FAMU-FSU College of Engineering, Tallahassee, FL 32310, USA
2High-Performance Materials Institute, Florida State University, Tallahassee, FL 32310, USA
3School of Physics Science and Engineering, Tongji University, Shanghai 200092, China

Abstract

This paper reports on the fabrication and characterization of piezoelectrets using three types of cyclic olefin copolymers (COCs). The COCs (COC 6017, 6013, 8007) differ considerably in their glass transition temperatures, thermal stability, and mechanical flexibility. The piezoelectrets were fabricated using a carbon dioxide assisted assembly of a multi-layer non-overlapping structure followed by contact charging. The piezoelectricity was characterized by quasi-static piezoelectric coefficients. Piezoelectrets from the three COCs all showed excellent piezoelectric activity with the quasi-static piezoelectric coefficient reaching up to 1600 pC/N. Thermal stability of the three types of piezoelectret were investigated by thermally stimulated discharge (TSD). The discharge peaks for 6017, 6013 and 8007 were found to be around 210 oC, 180 oC and 130 oC, respectively. The electrical and electromechanical characteristics of the piezoelectrets were further probed by electric hysteresis loop measurements, butterfly loop measurements and dielectric resonance spectra for all three types of materials.  The study provided the first systematic and comprehensive investigation of the potential of the family of COC copolymers in piezoelectric applications, broadening the materials choices and design space of porous polymer based piezoelectric materials.

Piezoelectrets from Cyclic Olefin Copolymers with Different Mechanical and Thermomechanical Properties: A Comparative Study