Linking the Chemistry and Physics of Electronic Charge Transfer in Insulators: Theory and Experiment

The surface states model is successful in predicting many salient features of charge transfer in insulative materials, which is critical to electrophotography. This article will discuss how the surface chemistry controls the physics and the chemical potentials, and how it fits the surface states model. The interrelationship of acid-base K-a/K-b values of the materials in contact, measured by inverse gas chromatography, the highest occupied molecular orbitals and lowest unoccupied molecular orbitals and their excited states calculated using DFT (density functional theory) quantum mechanical modeling, the chemical potentials measured by the Kelvin method, and triboelectric charging data are studied. It will be shown that a precursor complex of the contacting materials, prior to the charge transfer event, can be calculated by DFT to predict triboelectric charging both qualitatively and quantitatively. This article focuses on polytetrafluoroethylene, Kynar and PMMA polymers, as well as silica, titania, and alumina. (C) 2013 Society for Imaging Science and Technology.