Interfacial characteristics of a gas bubble immersed in a surfactant and protein laden fluid: Experimentation and modeling
Abstract
This dissertation is a study of macromolecule adsorption to a gas-liquid interface. This study is of broad interest to such diverse fields as material science, food science, cardiology, and polymer science. All of these fields involve the interfacial phenomena investigated here. In this undertaking, surface tension measurements of single protein solutions, single tri-block copolymer solutions, binary protein solutions, and protein tri-block copolymer solutions have been recorded as a function of time and bulk concentration. A model for the equilibrium surface tension of a single protein solution based on 3-D dense packing has been provided. The tri-block copolymer equilibrium surface tension behavior is accurately modeled by the Langmuir Isotherm in dilute concentrations. The equilibrium surface tension behavior of surfactant-protein and protein-protein mixtures has also been modeled. Here, competition has been found to be comprised of both steric and energetic competition. This new competitive model accurately captures previously unreported effects related to competitive adsorption, especially cooperative surface tension change at low bulk concentrations. ^ In addition to surface tension measurements, a novel Laser Scanning Confocal Microscopy method is described for the measurement of the adsorbed surface excess concentration. Modeling of protein adsorption has been, in general, confounded by the inability to accurately measure the surface excess at the gas liquid interface. The method described in this dissertation involves the imaging of fluorescently labeled protein molecules in a droplet placed on a microscope cover slip, and holds great promise. It is especially suited to measuring the surface excess of a small number of competing protein or surfactant species. ^
Subject Area
Engineering, Mechanical|Biophysics, General
Recommended Citation
Joshua Willard Lampe,
"Interfacial characteristics of a gas bubble immersed in a surfactant and protein laden fluid: Experimentation and modeling"
(January 1, 2007).
Dissertations available from ProQuest.
Paper AAI3292046.
http://repository.upenn.edu/dissertations/AAI3292046
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