Characteristics of PVDF Polymer Films Synthesized by Atmospheric Pressure Plasma Polymerization for Flexible Nanogenerator Applications

Nanogenerator (NG) based on the piezoelectric, which can convert mechanical energy to electric power, can be an interesting candidate for energy harvesting applications. These fabricated nanogenerators with nanomaterials have attracted lots of attentions since the first report on utilizing piezoelectric zinc oxide nanowires for mechanical energy harvesting
¹
. More and more piezoelectric nanomaterials have been researched in mechanical NG device such as ZnO, PZT, and BaTiO
3
. Compared with those inorganic nanomaterials in realistic applications, piezoelectric polymers are promising alternatives for flexible NG devices. Especially, polyvinylidene fluoride (PVDF) has a relatively high piezoelectric property owing to its polar crystalline structure, consisting of at least four different crystalline forms (namely
$\alpha, \beta, \gamma,$
, and
$\delta),$
among which
$\beta$
phase is primary for its piezoelectric activity
²
, In this study, in order to characterize the crystal structure and morphology of deposited PVDF polymer film by using novel atmospheric pressure plasma jets (APPJs) polymerization system, secondary electron microscopy (SEM), Fourier transforms-infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) have been investigated systematically for the energy-harvesting element of a flexible piezoelectric nanogenerator. From these results, SEM results show that PVDF nanoparticles are clearly observed and the thickness of PVDF polymer film is about 2
$\mu \mathrm{m}$
on flexible substrate by using novel APPJs at room temperature with PVDF/ DMF solution. The detailed characterization of PVDF polymer films using SEM, FT-IR, and XRD are under study and will be discussed in detail.