Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Formation and Stability of Surfactant-Stabilized, Spontaneous, Oil-in-Water Emulsions in Saline Environments" By Cole R. Davis Purdue MSE Preliminary Exam Advisors: Professor Carlos J. Martinez and Professor Kendra A. Erk ABSTRACT Spontaneous emulsification provides a low energy alternative to forming nano-sized emulsions in pharmaceuticals, enhanced oil recovery, detergency, and more. Although this method can be advantageous, spontaneous emulsification can be problematic in systems where oil and water mixtures are undesirable. These systems include wastewater and can introduce harmful oils (e.g., aromatics) into the environment. Literature involving spontaneous emulsification provides mechanisms for how these emulsions form, but little is done to precisely control the occurrence or rate of spontaneous emulsification. Furthermore, few papers exist that include the presence of salts during emulsification, which is highly relevant to many wastewater systems including bilge water. This study investigates the formation of spontaneous oil-in-water emulsions in saline environments and proposes the following hypothesis: the presence of salts found in seawater will act to promote spontaneous emulsification and may increasing the stability of surfactant-stabilized oil-in-water emulsions. To test this hypothesis, dynamic light scattering will be used to quantify the rate of emulsification for a variety of surfactant-oil-saltwater mixtures. Salinities will be selected based on calculated optimal salinity values where the hydrophilic lipophilic difference (HLD) is zero. Surfactant concentrations will also vary according to their respective critical micelle concentrations (CMCs) at different salinities to test the need for the presence of surfactant micelles during spontaneous emulsification. This work will provide a deeper understanding on the formation and stability of spontaneous emulsions in saltwater systems with the goal of building a model, based on the HLD model, that can be used to predict and ultimately prevent spontaneous emulsification in wastewater systems. Date: Wednesday, December 11, 2019 Time: 9:30 A.M. Place: ARMS 1021