BICONTINUOUS BIPHASIC LIQUID MEDIA FOR CATALYSIS AND SEPARATIONS

Orateur : Daeyeon LEE (Department of Chemical and Biomolecular Engineering, University of Pennsylvania / Chair, Nanosciences)

A recent approach that has shown great promise for biomass conversion and biofuel upgrade reaction involves using biphasic emulsions stabilized with interfacially active catalytic nanoparticles. It combines the advantages of phase transfer and heterogeneous catalysis. To enable continuous reactions and separations in a biphasic liquid mixture, we explore the formation of bicontinuous interfacially jammed emulsions (Bijels). Bijels are typically prepared by arresting spinodal decomposition of two fluid phases via interfacial attachment and jamming of colloidal particles. Their fabrication is currently limited to a few pairs of immiscible liquids, and bicontinuous morphology can be obtained within narrow composition and temperature windows. We explore the formation of bijels by solvent transfer-induced phase separation (STRIP) of ternary mixtures. The use of commercially available silica nanoparticles and ionic surfactants allows us to continuously form bijel fibers with controllable morphologies and domain sizes down to a few hundreds of nanometers. We study the dependence of fiber morphology on different control parameters such as particle and surfactant concentrations. We also develop a new in situ technique to characterize the mechanical properties of bijel fibers during different stages of their maturation. The potential of generating bijels that can be used in reactive separations for biofuel upgrade will be discussed.

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