Polarization profiles in corona poled P(VDF-TFE) copolymer studied by piezoelectrically induced pressure step method

Abstract

Polarization profiles have been measured with a resolution of about in corona poled 95:5 P(VDF-TFE) copolymer by using the piezoelectrically induced pressure step (PPS) method. A polarization peak is observed near the positive side of samples poled in a negative corona by the constant current technique. The distribution of polarization is also nonuniform in the case of a constant voltage poling at , but profiles are rather uniform if a poling field is applied at . In multilayer samples, the upper film bombarded by corona ions remains absolutely nonpolarized. Thin transition nonpolarized zones are seen near surfaces of even well polarized P(VDF-TFE). It is shown that polarization uniformity in P(VDF-TFE) is strongly affected by injection of negative charge carriers from the virtual electrode formed either on the surface bombarded by corona ions, or between two contacting dielectric surfaces. Our data on P(VDF-TFE) are in accord with those reported on other ferroelectric polymers.

Distribution of the Ferroelectric Polarization in Polyvinylidene Fluoride During Initial Poling and Polarization Reversal

“…The pressure wave propagated in the thickness direction creating a current pulse, the shape of which repeated the profile of the polarization distribution over the film thickness [2]. The method and the setup schematic were described elsewhere [2,6].…”

“…One of the important characteristics of charged PVDF films is the spatial distribution of polarization in the thickness direction, because the inhomogeneous distribution distorts piezoand pyroelectric activity [2]. Therefore, a few experimental methods were applied for studying the distribution of polarization, such as the laser-intensitymodulation (LIMM) [3,4], the laser-induced pressure pulse (LIPP) [5] and the piezoelectrically-generated pressure step (PPS) methods [2,6].…”

“…This effect was of significant practical importance and showed how strong the relationship between polarization and space charge was. A corresponding physical model has been suggested and described assuming important role of injected charges and their coupling with the already formed ferroelectric polarization [6][7][8][9].…”

Surface Modification of Fluoropolymers via Molecular Design

“…Corona discharge is usually employed to polarize the fluoropolymer surfaces and to induce the piezoelectric effect. [116,117] Corona discharge treatment can also produce oxygen-containing species on the fluoropolymer surface to improve the surface wettability. [118] Flame treatments are effective in the surface treatment of partially fluorinated polymers.…”

Effect of Ferroelectric Polarization on Carrier Transport in Controlled Polarization-Type Ferroelectric Gate Field-Effect Transistors with Poly(vinylidene fluoride–tetrafluoroethylene)/ZnO Heterostructure

“…When voltage is applied across the P(VDF-TeFE) layer, its polarization can be reversed through the rotation of the molecular chain. 18) P(VDF-TeFE) has a variable crystallization temperature related to the composition of VDF and TeFE, and can be crystallized at a low temperature of under 150 C. [19][20][21] In this study, we fabricated CP-type FeFETs with the P(VDF-TeFE)/ZnO heterostructure and investigated the carrier transport in the CP-type FeFETs by Hall effect measurement.…”