This award supports computational and theoretical research and education with the aim to elucidate the physical basis of triboelectric charging.
The project has two thrusts:
(1) Elucidation of triboelectric charging on a well-characterized system. The use of a well-characterized system will enable strong connections to be made with experiment and other simulations of related phenomena. The well-characterized system involves crystallographic surfaces of quartz and sapphire. These surfaces have been very actively studied and are relatively well understood. Molecular dynamics simulations will be performed to analyze partitioning and free energy profiles for ions in thin water layers between two solid surfaces. A better understanding of the ion transfer mechanism should enable insight into when this mechanism, as opposed to an electron transfer mechanism, is applicable and what parameters affect charging by the ion transfer mechanism.
(2) Development of a coarse-grained model to describe triboelectric charging between surfaces of identical chemical composition. A fundamental understanding of the charging in this case remains unclear. Since the surfaces have the same chemical composition, this symmetry would seem to preclude a driving force for charge transfer. The PI will endeavor to include undergraduate researchers in a meaningful way. In the past 13 years, 17 undergraduate researchers from the PI's group have been coauthors of journal articles. The PI also aims to train scientists and engineers with a global perspective, with a particular focus on sub-Saharan Africa. The study of triboelectric charging has led to interactions with universities in Botswana and Niger.
NON-TECHNICAL SUMMARY This award supports computational and theoretical research and education on triboelectric charging, the electrostatic charging that occurs when two surfaces rub. While everyone appreciates whimsical effects like the mild shock when a doorknob is touched after walking across a carpet, triboelectric charging has a wide range of important applications in industry, including imaging technologies and pneumatic conveying, and consequences for natural phenomena, such as dust devils, and volcano plumes. There are important scientific aspects of triboelectric charging that are in essence completely unknown - for example, it is not clear whether the species transferred between surfaces are electrons, ions or bits of material, and whether rubbing the surface merely increases the contact area between surfaces or introduces stresses that enhance charge transfer. This project aims to apply computer simulation techniques to model experimentally well characterized materials down to the level of individual atoms with the aim of elucidating the origins of triboelectric charging. Of particular interest are systems where the materials that are rubbing are identical. The PI will endeavor to include undergraduate researchers in a meaningful way. In the past 13 years, 17 undergraduate researchers from the PI's group have been coauthors of journal articles. The PI also aims to train scientists and engineers with a global perspective, with a particular focus on sub-Saharan Africa. The study of triboelectric charging has led to interactions with universities in Botswana and Niger.
