(3au) Electrostatics In Chemical and Material Processing

My past research has utilized electrostatics principles to produce unique materials. I have investigated the fundamentals of producing nanomaterials from electrohydrodynamic processes such as electrospinning and electrospraying from a free liquid surface. In this process, electrostatic forces repel surface charges to form Taylor Cones, resulting in electrostatically driven jets or droplets. The electrostatic forces cause the charged liquid to accelerate toward a grounded collector which enhances evaporation and eventually leads to solidification of the jets and droplets, producing nanomaterials with high surface areas and porosities. These materials can be applied in a wide range of fields such as textiles, filtration, tissue engineering, drug delivery systems, pharmaceuticals, nanocomposites, and alternative-energy generation systems including solar cells, fuel cells, and energy storage devices.  Correlations have been developed to predict productivity and fiber diameter based upon solution properties, operating parameters, and system configuration.

In addition, my work has focused on the commonly observed, yet poorly understood, electrostatic phenomena of contact charging also known as triboelectrification.  In this process, two initially neutral surfaces come in contact with each other and a subsequent transfer charge occurs. Once the two surfaces are separated, an equal but opposite polarity charge remains on the charge surface. The polarity of the surface charge and amount of charge transfer has been empirically studied, however it remains highly debated whether or not ions and/or electrons are responsible for charge transfer. This contact charging produces problems for manufacturing chemicals and materials, particularly in the case of granular materials. Due to the surface area to volume ratio, large amounts of charge can accumulate in granular materials (both in multi-component and single-component systems). A kinetic gas model was employed to determine the frequency of collisions between granular particles. It showed an unbalanced accumulation of the charge transfer species (positive, negative ions, and/or electrons) on the relatively smaller size particles. This model explains the observed behavior of single component systems in which the relatively smaller size particles charged negatively and the larger particles charged positively. This result suggests a negative transfer species (i.e. negative ions and/or electrons) between surfaces.