Evolution of electromechanical and morphological properties of piezoelectric thin films with thermomechanical processing

Publication date: 5 December 2016
Source:Polymer, Volume 106
Author(s): Zhe Xu, Mahmoud Baniasadi, Salvador Moreno, Jizhe Cai, Mohammad Naraghi, Majid Minary-Jolandan
Piezoelectric polymers (PVDF and its co-polymers) in film and nanofiber forms are increasingly used for sensing, actuation and energy harvesting. Given the semi-crystalline structure of these polymers, their electromechanical coupling behavior changes with thermomechanical processing. This article reports on the evolution of the mechanical properties, piezoelectric properties and morphology of P(VDF-TrFE) poly[(vinylidenefluoride)-co-trifluoroethylene] piezoelectric polymer thin films fabricated by spin-coating during thermal annealing and drawing, studied via tensile test, polarized optical microscopy, X-ray diffraction, polarized FTIR, and piezoresponse force microscopy (PFM). The results show that annealing and drawing process result in ∼10 and 13 folds improvement in the elastic modulus and strength of the films, respectively. In addition, the piezoelectric constant and electromechanical coupling improves by 30% and more than 17 times, respectively. These changes are accompanied by 65% increase in the percentage of the crystallinity of the semi-crystalline piezoelectric films, compared to the as-fabricated films.

Graphical abstract

http://ift.tt/2ety4zX