Tribology and the Triboelectric Effect: A study into the influence of tribological factors on frictional electrification

The triboelectric effect has long been understood as the phenomenon of electric charge transfer resulting from mechanical contact. Although this has long been observed in a multitude of circumstances, ranging from daily life to specific engineering applications, a significant knowledge gap remains regarding the mechanisms that describe triboelectric charge transfer. Research into the triboelectric effect has however seen a recent surge in the previous decade, owing to the conception of the triboelectric nanogenerator (TENG) and its subsequent applications in energy recycling and self-powered sensing. Existing research now entails various models for predicting the output of TENG devices from an electrical engineering standpoint, in addition to qualitatively describing the mechanisms that drive triboelectric charging. However, many of these models fall short with regards to describing the role of tribological factors in these physical mechanisms. Similarly, the field of tribology has only recently begun to expand its interests into triboelectric phenomena. This research plays a key part in discerning the influence of tribology on triboelectric mechanisms and applications. Factors such as surface composition, contact topography, normal and tangential forces, and relative motion are determined, as well as the effects of material wear and the presence of contaminating media. This is achieved primarily through the modification of a mechanical testing apparatus with the integration of a high-impedance electronic measurement circuit for the correlation of mechanical and electrical measurements. Ultimately, a semi-analytical model is also constructed using these data as a way of providing a stepping stone towards a fundamental understanding of all aspects of the triboelectric effect.