We investigate four examples of interfacial phenomena using continuum and molecular modeling and simulation. Surfaces with time-varying wettability find applications in emerging technologies such as biochemical sensing, microfluidics, and self-cleaning coatings. The first example investigates thin film behavior on such surfaces as a function of the amplitude, frequency and phase of the wettability variation. We obtain the strength, frequency, and phase of wettability variation required to alter a wettable surface into a non-wettable one, and vice versa. The second example investigates the role of surfactants and fluid elasticity in the Faraday instability of inertialess fluids since the Faraday instability could potentially be used for creating patterned surfaces and is a model system for studies of patient formation in nonlinear systems. We find that the presence of surfactants or fluid elasticity is required to generate the Faraday instability in inertialess fluids. Melt spinning, a micro-fiber production process, has a higher production rate than currently used processes. We investigate melt spinning of materials possessing a step-like change in viscosity (e.g., block copolymers) with temperature in the third example. We find that with sufficiently strong external heating, melt spinning could potentially produce nanofibers. These three examples are studied using continuum modeling and simulation. The fourth example explores dendrimer adsorption using molecular modeling and simulation. Dendrimers, regular hyperbranched polymers, are expected to be used in drug delivery and surface functionalization, making it important to investigate dendrimer adsorption, We find that an adsorbed dendrimer adopts a disc-like conformation by compressing in the direction normal to and extending in the direction parallel to the adsorbing surface. Terminal groups can be placed at the dendrimer periphery, near the center of mass and can be distributed in the dendrimer volume depending on dendrimer-surface interactions and dendrimer charge/hydrophobic group distributions. In the presence of shear flow, an adsorbed dendrimer tumbles with the vorticity direction as an axis of rotation, and translates in the flow direction. Our results contribute to the understanding of interfacial instabilities, melt spinning, and dendrimer adsorption, in addition to providing guidelines for patterning of surfaces, nanofiber production, and dendrimer design for various applications.However, certain individuals were absolutely key to completing this thesis. ... I am also obliged for his immense help in improving my writing and presentation skills. I would also like ... Tsapatsis for serving as PhD defense committee chair and being available for discussing my graduate study problems and career planning.
|Title||:||Continuum and Molecular Modeling of Interfacial Dynamics: Interfacial Instabilities, Melt Spinning, and Dendrimer Adsorption|
|Publisher||:||ProQuest - 2008|