Phase-separation in Mixed Surfactant Monolayers, or Why "Lipophobic" is a Bad Word
Dr. Matthew Paige
(University of Saskatchewan)

ABSTRACT: 
Surfactant monolayers consisting of a mixture of hydrogenated and perfluorinated compounds tend to undergo phase-separation at the air-water interface to form highly-ordered surfaces. My research group has been attempting to understand the underlying molecular and thermodynamic factors which contribute to the diverse morphologies observed in these mixed systems. Recently, we have begun to explore the use of synchrotron-based liquid surface x-ray scattering methods, including Glancing Incidence X-ray diffraction and X-ray reflectivity, to probe molecular-scale packing and organization of film components at the air-water interface. These approaches have led to new insight into factors which control micron-scale film morphology. I discuss these new measurement results in the context of previous experiments, particularly in terms of the properties of the perfluorinated surfactant component, the behaviour of which is often not appropriately described in the literature.  Time allowing, I will also discuss some recent results involving single-molecule fluorescence imaging of phase-separated, luminescent polydiacetylene fibers, and the potential for inter- and intramolecular energy transfer in these systems.

BIO:  Dr. Matthew Paige is the Thorvaldson Professor and Department Head at the University of Saskatchewan. The common theme that connects various research interests in the Paige group is the use of high-sensitivity, high-resolution spectroscopy and microscopy approaches for answering important scientific questions. Our research spans both fundamental and applied areas of investigation.

Dr. Paige is the guest of Dr. Christine DeWolf