• Misture, Scott T.
• Jones, Jacob L.
• Paterson, Alisa R.
• Choi, Andrew C.
• Ren, Yang
• Borkiewicz, Olaf C.

Abstract

Ferroelectric polymers have gained tremendous attention due to several attractive properties including high breakdown strength, low dielectric loss, relatively fast charge/discharge rates and greater flexibility than their ceramic counterparts. In order to achieve enhanced energy efficiency in high-energy storage capacitor applications, it is desirable to obtain slim polarization hysteresis loops for ferroelectric polymer films. Here, it has been demonstrated that promotion of large crystallites and γ phase content through thermal annealing provides a cost-effective way to obtain a quasi-linear polarization response in a PVDF co-polymer thin film. The polarization mechanisms underlying a thin hysteresis loop in the thermally annealed film are elucidated using direct experimental insights from in situ synchrotron diffraction with two-dimensional detection. It has been demonstrated that the susceptibility for electric-field-induced structural changes is higher in the defective ferroelectric phase γ than the polar phase β, due to a higher flexibility for accommodation of gauche bond along the carbon chain. In addition, the polymer chains in the γ phase also exhibit a range of different responses depending on their orientations with respect to the electric field. These results are broadly significant as they provide a fundamental basis for rational design of phase assemblages to obtain tailor-made properties in ferroelectric polymer films.

Topics

• impedance spectroscopy
• polymer
• Carbon
• phase
• thin film
• strength
• two-dimensional
• annealing
• ceramic
• susceptibility