Description
- Abstract:
- Living cells depend on electrochemical potentials across membranes for many crucial cell functions. Electric fields are also used in engineering applications such as the electroporation of cells, allowing for the transport of molecules across a cell membrane. The fundamental concept underlying these phenomena is the dynamic response of a cell membrane to an electric potential, which remains poorly understood. The approach taken in my thesis is to study interfacial dynamics in electric fields by using the foundations of fluid-fluid interfaces to guide the study of complex behavior of bilayer membranes. <br/><br/> Artificial cell-sized membrane envelopes are used as a model system to visualize interfacial dynamics with light microscopy, which are then compared to analytical theory. The dynamics of model membranes are studied experimentally in both AC and pulsed DC electric fields. Due to the finite thickness of the interface, bilayer capacitance is critical to membrane dynamics. A novel method is developed that utilizes micro-scale morphological changes to measure membrane capacitance, an important parameter for membrane stability in electric fields. Two behaviors are investigated: shape dynamics and collapsing behavior of vesicles in a DC pulse and the measurement of membrane fluctuations in an AC field. <br/><br/> Vesicle response to an electric field bears similarity to drops, therefore the stability of drops in electric fields is explored. New features are investigated, particularly the unsteady behavior of a viscous fluid drop in a DC electric field. Viscosity contrast is shown to be critical to drop dynamics in a combined rotational and extensional flow generated by an electric stress at the interface. The dynamics of drops in an electric fields has potential applications in its own right, for instance electrorheological fluids and oil separation technologies.
- Notes:
- Thesis (Ph.D. -- Brown University (2013)
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Citation
Salipante, Paul F.,
"Electrohydrodynamics of Simple and Complex Interfaces"
(2013).
Fluid, Thermal, and Chemical Processes Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://doi.org/10.7301/Z0W66J3F
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Fluid, Thermal, and Chemical Processes Theses and Dissertations
Theses and Dissertations for the Fluid, Thermal, and Chemical Processes department....