Simultaneous stretching and corona poling of PVDF films

Abstract

Simultaneous stretching and corona poling (SSCP) of polyvinylidene fluoride (PVDF) films at elevated temperatures in batch mode greatly enhanced the piezo- and pyroelectric constants. When poled under optimum conditions, a piezoelectric constant d31 approximately 60 pC N-1 and a pyroelectric constant p approximately 6 nC cm-2 K-1 at 30 degrees C were obtained. Both these values are about twice the best values found by the authors, and other workers, for films that were first stretched and then corona poled. The time stability of d31 at all temperatures was also greatly improved by SSCP. They postulate that there is a greater contribution of whole beta crystallite rotation in these SSCP films. X-rays show that they have enhanced beta phase over those that are first stretched and then poled.

The Role of Solution Phase Water on the Deposition of Thin Films of Poly(vinylidene fluoride)

“…This form can be produced by crystallization under high pressure, poling in a high electrical field, solid-state extrusion, rolling, or stretching of unoriented PVDF films. [11][12][13][14][15] Polymer films are commonly obtained in the R and γ crystalline form when deposited from solution. Few papers describe methods to produce solution cast polymer films in its unoriented phase.…”

Structural characterization of blends containing both PVDF and natural rubber latex

“…The other phases are all polar and thě -phase is of special interest due to its large pyro-and piezoelectric activity. 1,2 PVDF-ˇcan be reached from the˛-phase using different processes such as mechanical deformation, 3,4 application of very intense electric fields, 5,6 annealing at temperatures above the glass transition temperature 7 or even casting a PVDF solution onto a solid substrate at controlled temperatures. 8 Together with its excellent mechanical properties and biocompatibility, these ferroelectric and electrical properties make PVDF a suitable material for electro-optical and electromechanical devices 9,10 and in applications in biomedical engineering 11 to produce bone healing 12 and artificial tissues and prostheses.…”

Novel Electroceramic: Polymer Composites - Preparation, Properties and Applications

“…In some cases for poling polymers, film is stretched while the corona discharge is on. This produces uniform orientation of domains and large piezoelectric coefficients (Sessler, 1994;Das-Gupta and Doughty, 1986;Kaure et al, 1991). In field poling, an applied field is up to 10 MV/m and poling time is usually a few seconds.…”