Static Electrification of Plastics under Friction: The Position of Engineering‐Grade Polyethylene Terephthalate in the Triboelectric Series

Abstract

There is an emerging trend to replace moving metallic parts, such as bearings or bushes, with plastic components. The electrostatic hazard associated with plastic components subject to mechanical friction is well documented, but the magnitude as well as physical–chemical origin of this phenomenon remains debated. Using atomic force microscopy and Faraday pail measurements, the triboelectrification of Ertalyte®, a commonly used bearing‐grade formulation of polyethylene terephthalate, when rubbed against other polymers and metals, is studied. The sign and magnitude of the net charge that Ertalyte® gains in relation to the chemical nature—electron affinity and ionization energy—of the contacting material are analyzed, concluding that this material should be located toward the negative end of the triboelectric series. It is also shown that large charge densities and fast charge decays result from contact of Ertalyte® with polymers of a small Derjaguin–Muller–Toporov (DMT) modulus and unstable ions, suggesting that ion transfer leads to the electrification of a dynamic insulator/insulator contact. These findings have immediate implications in the choice of the material used to manufacture plastic parts subject to friction and wear and to help address ongoing fundamental questions over the nature of the charge carriers that leads to static electricity.

Passivation of miniature microwave coplanar waveguides using a thin film fluoropolymer electret

“…This is approximately the same as silicon dioxide used in MOS structures 49 , 50 . The election affinity of poly(tetrafluoroethylene) fluoropolymer is cited as ~ − 0.8 eV 77 , compared to 0.9 eV for silicon dioxide 78 . Using these values, the value of the positive charge in the fluoropolymer layer is calculated to be 5.72 × 10 –7 C cm −2 (p-type MIS) and 5.11 × 10 –7 C cm −2 -n-type MIS).…”

Electrostatics and Electrochemistry: Mechanism and Scope of Charge-Transfer Reactions on the Surface of Tribocharged Insulators

“…However, this is not the case. Rubbing two pieces of the same material leads to static electricity. , This observation is mirrored by a related fact; that is, different formulations of a given polymer, such as polyethylene terephthalate in the form of either Mylar or Ertalyte, , take up different positions in the triboelectric series. This indicates that mechanochemical aspects underlie contact electrification, , including substrate softness, adhesion, and roughness …”

“…This phenomenon, referred to as contact- or triboelectrification, has widespread practical consequences and applications. For example, it underpins seemingly unrelated phenomena and technologies, such as a car’s static zip, the failure of automotive bearings, and the transfer of inks in xerography . The first written account on the static charging of an insulator is generally attributed to Thales of Miletus, who lived around 600 B.C .…”

Electrostatic Charges Regulate Chemiluminescence by Electron Transfer at the Liquid–Solid Interface

“…Fortunately, over the last 5–10 years, a growing number of research groups have noticed one type of electrostatic field, which can be simply generated by contact electrification without any applied voltage or additives. − Static charges develop on the surface of electrically insulating materials that are first brought in contact with and then macroscopically separated from another solid. , Recent studies show that this phenomenon is not limited to the solid/solid interface but also occurred at the liquid/solid or liquid/liquid interface. − Based on the contact charging at the liquid/solid interface, our group developed a self-powered droplet triboelectric nanogenerator with spatially arranged electrodes as a probe for measuring the charge transfer (CT) between liquid and solid interfaces and showed that the electron transfer is the dominant CT species in the case of liquid/solid contact . This inevitably raises a challenge about the reproducibility of the chemical reaction in the liquid solution as chemical reactivity is governed by the movement and transfer of electrons, and electron transfer is most likely to occur at the interface between the reaction solution and the surrounding environment or the container, , such as air, beaker and pipette, when preparing the reaction solution.…”

“…7−10 Static charges develop on the surface of electrically insulating materials that are first brought in contact with and then macroscopically separated from another solid. 11,12 Recent studies show that this phenomenon is not limited to the solid/solid interface but also occurred at the liquid/solid or liquid/liquid interface. 13−19 Based on the contact charging at the liquid/solid interface, our group developed a self-powered droplet triboelectric nanogenerator with spatially arranged electrodes as a probe for measuring the charge transfer (CT) between liquid and solid interfaces and showed that the electron transfer is the dominant CT species in the case of liquid/solid contact.…”