Student Research

Environmental and hydrophilic effects on the triboelectric charging of insulator materials

Triboelectric charging is a natural phenomenon that often plagues many manufacturing processes. Electrical charge is transferred when two material surfaces contact each other. This phenomenon attributes to a wide range of occurrences, such as volcanic lightning and grain silo explosions. Currently, the mechanisms and variables that affect triboelectrification are unclear and poorly understood. Three mechanisms: electron, ion, and mass transfer, are believed to be responsible for the charge transfer and are considered explanations for the occurrence of triboelectric charging. Variables, such as relative humidity and hydrophilicity, contribute to the sign and magnitude of charging that transpires. To investigate these variables and the mechanisms responsible for triboelectric charging of insulators, a simple experimental approach was created, whereby a particle (300-800 μm) is gravitationally driven through a spiraled insulator tube (ID 1.5 mm). The tube is held in a controlled chamber in order to hold a near zero humidity environment. Different particle materials (soda lime glass, polystyrene) and tube materials (Nylon, Teflon) were studied due to their inherently different hydrophilicities. The rate of charge accumulation was recorded as the particle traversed through the segments of insulator tubing. The charged particles were collected in a Faraday cup and the total accumulated charge on each particle was calculated. This study aims to isolate triboelectric charging at or near zero relative humidity as well as to gain a better understanding of the mechanisms responsible for triboelectric charging of insulators.


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