Dependence of triboelectric charging behavior on material microstructure

We demonstrate that differences in the microstructure of chemically identical materials can lead to distinct triboelectric charging behavior. Contact charging experiments are carried out between strained and unstrained polytetrafluoroethylene samples. Whereas charge transfer is random between samples of identical strain, when one of the samples is strained, systematic charge transfer occurs. No significant changes in the molecular-level structure of the polymer are observed by XRD and micro-Raman spectroscopy after deformation. However, the strained surfaces are found to exhibit void and craze formation spanning the nano- to micrometer length scales by molecular dynamics simulations, SEM, UV-vis spectroscopy, and naked-eye observations. This suggests that material microstructure (voids and crazes) can govern the triboelectric charging behavior of materials.