Structure and Dielectric Properties of Poly(vinylidenefluoride-co-trifluoroethylene) Copolymer Thin Films Using Atmospheric Pressure Plasma Deposition for Piezoelectric Nanogenerator

Abstract

This study investigates the structural phase and dielectric properties of poly(vinylidenefluoride-co-trifluoroethylene) (P[VDF–TrFE]) thin films grown via atmospheric pressure (AP) plasma deposition using a mixed polymer solution comprising P[VDF–TrFE] polymer nano powder and dimethylformamide (DMF) liquid solvent. The length of the glass guide tube of the AP plasma deposition system is an important parameter in producing intense cloud-like plasma from the vaporization of DMF liquid solvent containing polymer nano powder. This intense cloud-like plasma for polymer deposition is observed in a glass guide tube of length 80 mm greater than the conventional case, thus uniformly depositing the P[VDF–TrFE] thin film with a thickness of 3 μm. The P[VDF–TrFE] thin films with excellent β-phase structural properties were coated under the optimum conditions at room temperature for 1 h. However, the P[VDF–TrFE] thin film had a very high DMF solvent component. The post-heating treatment was then performed on a hotplate in air for 3 h at post-heating temperatures of 140 °C, 160 °C, and 180 °C to remove DMF solvent and obtain pure piezoelectric P[VDF–TrFE] thin films. The optimal conditions for removing the DMF solvent while maintaining the β phases were also examined. The post-heated P[VDF–TrFE] thin films at 160 °C had a smooth surface with nanoparticles and crystalline peaks of β phases, as confirmed by the Fourier transform infrared spectroscopy and XRD analysis. The dielectric constant of the post-heated P[VDF–TrFE] thin film was measured to be 30 using an impedance analyzer at 10 kHz and is expected to be applied to electronic devices such as low-frequency piezoelectric nanogenerators.

A Review of Plasma-Synthesized and Plasma Surface-Modified Piezoelectric Polymer Films for Nanogenerators and Sensors

“…[38] 2.1.2. Plasma Deposition and Synthesis Process of the Piezoelectric Polymer Using APP Technique Jung et al [39] examined the structural and dielectric properties of P[VDF-TrFE] copolymer thin films grown by APP deposition using a mixed polymer solution comprising P[VDF-TrFE] nanopowder and dimethylformamide (DMF) solvent, as depicted in Figure 7a. In the APP deposition system, the length of the glass guide−tube is an important parameter when producing intense cloud-like plasma for polymer deposition.…”

“…Thus, the dielectric constant of the post-heated P[VDF-TrFE] thin film at 160 • C for 3 h was 30 at 10 kHz and room temperature. Accordingly, post-heated piezoelectric P[VDF-TrFE] copolymer thin film prepared by APP deposition is expected to be a prospective piezoelectric polymer material for flexible PENG [39]. dielectric constant values decreased with increasing frequency due to dipole dispersion in the polymer structures [39].…”

“…Accordingly, post-heated piezoelectric P[VDF-TrFE] copolymer thin film prepared by APP deposition is expected to be a prospective piezoelectric polymer material for flexible PENG [39]. dielectric constant values decreased with increasing frequency due to dipole dispersion in the polymer structures [39]. Thus, the dielectric constant of the post-heated P[VDF-TrFE] thin film at 160 °C for 3 h was 30 at 10 kHz and room temperature.…”

“…Thus, the dielectric constant of the post-heated P[VDF-TrFE] thin film at 160 °C for 3 h was 30 at 10 kHz and room temperature. Accordingly, post-heated piezoelectric P[VDF-TrFE] copolymer thin film prepared by APP deposition is expected to be a prospective piezoelectric polymer material for flexible PENG [39]. Jung et al [40] systematically investigated the effects of post-heating treatment on the crystalline phase of a PVDF thin film fabricated through APP deposition using a PVDF/DMF solution.…”

“…To solve this problem, low and atmospheric pressure plasma (APP) processes have recently attracted attention because of their specific properties, such as pinhole-free and cross-linked structures for polymer film deposition and plasma surface modification [ 31 , 32 , 33 , 34 ]. Recent research related to plasma processes for piezoelectric NPs and polymers has also been conducted [ 35 , 36 , 37 , 38 , 39 , 40 , 41 ]. Here, we will deal with polymerization and applications using plasma in more detail.…”