Interfacial curvature of surfactant systems

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The goal of the interfacial curvature program is to use chemical engineering principles to design products and processes involving Surfactant-Oil-Water (SOW) systems. We have used the hydrophilic-lipophilic-difference (HLD) + net-average curvature (NAC) as equation of state (EOS) for SOW systems to formulate products such as self-microemulsifying delivery systems (SMEDS) for pharma and food ingredients, and Targeted Emulsified Solvent Injection (TESI) for bitumen recovery. Our food-grade, lecithin SMEDS improves the bioavailabity of common drugs by about 4 times compared to dispersions. TESI has the potential to reduce by 80% the energy consumption and green house gasses of Steam Assisted Gravity Drainage (SAGD). Because of its versatility and use in real applications, the HLD-NAC has become a benchmark EOS for the surfactant industry. Past findings pointed us to new opportunities. The first one involves fixed charges in the Integrated Free Energy Model (IFEM). IFEM rivals HLD-NAC, but we developed IFEM from molecular thermodynamics. Exploring charges will make IFEM suitable for ionic surfactants (~60% of all surfactants), will enable exploring polar oils (common in food and pharma) and answer the long-standing question of Hoffmeister salt effects. We learned that HLD-NAC also describes the cloud point of nonionic surfactants, and surprisingly, even features of lyotropic liquid crystal (LLC) behavior. The second aim is to understand why HLD-NAC can predict LLC features and how we can use them to design structured materials (polymers). Preliminary work shows that we can produce nanostructured polymer-nanoparticle composites and nanostructured polymer gels with potential use in catalysis and water treatment. The third aim was born out of a surprising observation that our lecithin-SMEDS, designed with HLD-NAC, extended the circulation times of a drug, suggesting a potential modification in the way lipids and lipoproteins exchange material with tissue. By exploring the lipoprotein-SMEDS interaction we hope to understand if and how SMEDS can alter lipid distribution, and its potential use in lipid management, including parenteral nutrition. The fourth aim is to bring in transport phenomena principles, HLD-NAC as equation of state, and incorporate them in flow simulators that could work with self-emulsified solvent processes, particularly TESI. This integrated system is expected to help us design optimal hydrodynamics that would ensure that TESI can maintain or increase its oil recovery capacity (~80%, better than 60% for SAGD) in 2D models of oil sand reservoirs. Alumni trained in the program have gone on to lead R&D divisions for Canadian companies, and one is starting his own company to implement technologies from the program. The lack of expertise in SOW systems, in most engineers, suggest that the 4 PHDs and 5 undergrad trainees will be well positioned to make significant contributions in their respective careers.