L. L. Handy Colloquium Seminar

Smart Surfactants and Ligands in Pharmaceutical,
Environmental, and Energy Applications Professor Keith P. JohnstonDepartment of Chemical Engineering
The University of Texas at AustinABSTRACT Smart surfactants and ligands are being designed to (1) perform multiple functions, (2) achieve targeted activity at particular interfaces, and (3) be active at unusual interfaces, for example, in CO2. In pharmaceutical science, one of the key challenges is particle engineering of poorly water soluble drugs to achieve high bioavailability for oral and pulmonary administration. Increasingly, two goals are being pursued simultaneously: (1) control of particle nucleation and growth to achieve the desired particle morphology and (2) rapid wetting and dissolution, and in some cases high levels of supersaturation. Studies of fundamental thermodynamic, transport and interfacial mechanisms are leading to improvements in bioavailability in vivo.
Environmentally benign carbon dioxide-based emulsions may replace toxic organic solvents for pharmaceutical, chemical, materials, and microelectronics processing applications. Surfactants stabilize CO2-in-water emulsions or foams needed to control mobility in CO2-enhanced oil recovery, for producing 60 billion barrels of oil (approximately $6 trillion value). Nonionic methylated branched hydrocarbon surfactants emulsify up to 90% CO2 in water with polyhedral cells smaller than 10 microns, with the potential for excellent mobility control.
An emerging understanding of the role of surfactants in charging and stabilization mechanisms for colloids in low-permittivity solvents (dielect. const. < 5) will help advance a variety of applications including electrophoretic displays and electrophoretic deposition of nanocrystals to form superlattices. On the basis of novel experimental measurements for both hydrophilic and hydrophobic TiO2, a general mechanism is presented to describe particle charging in terms of preferential partitioning of cations and surfactant anions between the particle surface and reverse micelles in the bulk solvent. The design of smart surfactants and ligands for nano- and micron-sized emulsions and particle dispersions is in its infancy, and many new concepts will be developed for pharmaceutical, environmental, and energy applications.

Location: Olin Hall of Engineering (OHE) - 122

Audiences: Everyone Is Invited

Contact: Petra Pearce