Enhancement of ferroelectric phase and dielectric properties of P(VDF-HFP) by NiCl₂⋅6H₂O nucleating agent

Abstract

This work focuses on an improvement of dielectric properties of poly(vinylidene fluoride-co-hexafluoropropylene) or P(VDF-HFP) via mixing with different nickel(II) chloride hexahydrate (NiCl₂⋅6H₂O) contents (0–2 wt%). The nanocomposite films have been prepared by a conventional solution technique. The results reveal that the surface roughness increases with increasing salt content. The NiCl₂⋅6H₂O salt has no significant effect on the crystallinity of films. Additional incorporation of NiCl₂⋅6H₂O in the polymer leads to the growing conductivity. However, the considerable enhancement in dielectric constant with the relatively low dielectric loss tangent (0.1–0.3) can be found because of the formation of β-phase nucleation of NiCl₂⋅6H₂O in the P(VDF-HFP) matrix. The maximum value of calculated β-phase fraction of the nanocomposite is achieved 86% for salt content 0.5 wt%. Moreover, the largest dielectric constant (29.2 at 10 Hz) of the film doped 2 wt% NiCl₂⋅6H₂O is about 7 times greater than that of the pure P(VDF-HFP). The findings in this research suggest that the NiCl₂⋅6H₂O/P(VDF-HFP) nanocomposite is a candidate dielectric material for the next generation of energy conversion components.

Keywords:

• P(VDF-HFP)
• NiCl₂⋅6H₂O
• ferroelectric phase
• dielectric property
• phase transformation
• hydrated salt

Acknowledgments

The authors would like to thank the Department of Physics, Faculty of Science, King Mongkut's Institute of Technology Ladkrabang and the Center of Excellence in Nanotechnology for Energy (CENE), Prince of Songkla University, for instrumental supports. The Science Achievement Scholarship of Thailand (SAST) is gratefully acknowledged for the research funding as well.