Surface potential stability of large-area Teflon PTFE electret dosimeters of different thicknesses

Abstract

The effects of charge polarity and thickness on the surface charge potential stability responses of large-area Teflon polytetrafluoroethylene (PTFE) discs electrostatically charged by a new “modified single point-to-plane corona poling rotating system” were studied. Large-area Teflon discs (6 cm diameter) with 0.2, 0.5 and 1 mm thicknesses were used to produce both negatively or positively charged Teflon discs, at the same charging conditions. The deposited charge potential stability of the Teflon discs of different thicknesses monitored by a non-contacting electrostatic voltmeter for an extended time were monitored up to 77 days. Some inter-related parameters such as surface charge potential and external electrostatic field, internal electrostatic field, surface charge density, and the storage duration were also studied. The thick large-area Teflon disc electrets produced provided a steady-state charge stability on either negative (0.2, 0.5 and 1 mm thick) or positive (1 mm thick) surface charge potentials for the long period studied. The Teflon electret discs produced demonstrated having the highest charge potential stability in thicker electrets (1 mm), either negative or positive polarity, with provision of high potential for different applications in general and radiation protection dosimetry in particular.

Evolution of the electrical characteristics of an atmospheric pressure dielectric barrier discharge system over one hour operation

“…They also found out that, even at a 100 • C, films having a high surface potential initially (around −4 kV) decreased to 72% of that value after 700 h, while the ones having lower surface potential (between −1 kV and −1.5 kV) remained constant. Very good stabilities on PTFE discs of 200 µm, 500 µm and 1000 µm were also obtained by Sohrabi and Komijani [32] with corona charging as well. The stability was thought much better for negatively charged PTFE.…”

Stretchable π-conjugated polymer electrets for mechanoelectric generators

“…It is also believed that the reduction in the elastic modulus upon heating aids charge diffusion into the electret and promotes thermally driven charge injection processes, allowing a higher volumetric charge density and stable charge retention to be achieved. For this reason, electret poling is routinely performed under heat [34]. Charge injection efficiency was found to be dependent on elastic modulus in our previous work [24]; under the same conditions, materials with lower elastic moduli were more likely to be poled.…”

Organic molecular and polymeric electrets toward soft electronics

“…Since fluorine is the most active non-metallic element in nature, the bond with carbon atoms is sufficiently strong, which is the reason for the chemical inertness of fluoropolymers. 32 Representative fluoropolymers are PTFE, 18 perfluoroalkoxy alkane (PFA), [48][49][50] and polyIJperfluoro-3butenyl-vinyl ether; cyclic transparent optical polymer; CYTOP 35,51 (see Table 1). a. PTFE.…”

“…Even though this type of electret exhibits high surface charge density, it suffers from poor durability and unreliability. 17 While among organic electrets, the dominant dielectric materials are polymers, such as polytetrafluoroethylene (PTFE), 18 polyethylene (PE), [19][20][21] polypropylene (PP), 22 polyethylene terephthalate (PET), 23 polyimide (PI), 24 polyIJmethyl methacrylate) (PMMA), 25 polyvinylidene fluoride (PVDF), 26 and ethylene vinyl acetate (EVA). 27 Typical representatives of organic electret are shown in Table 1.…”