Ph.D in Biophysical Chemistry (2013)
University of California, Santa Cruz
Advisor: Professor Olof Einarsdottir
B.S. in Biological Sciences with a minor in Chemistry (2005)
California State University, Chico
Water is essential for life in a myriad of molecular and biological processes. I am interested in studying the interactions and behaviors of model biologically important systems at the interface of oil and water.
Currently, I am looking at self-assembling peptoid monolayers at the oil-water interface. Peptoids are a chemically diverse class of bio-inspired polymer in which the side chain ligands are attached to the nitrogen atoms of a glycine backbone. The interchangeability of the peptoid side chain functional groups enables these polymers to form a variety of secondary and tertiary structures. Of particular interest are peptoid nanosheets, which form from certain amphiphilic peptoid sequences through the compression of a key air-water monolayer intermediate resulting in highly organized 2D bilayers. Nanosheet formation can also occur via an oil-water interface, which can expand the diversity of applications for these novel 2D materials that include catalysts, molecular sensors, and artificial membranes. The oil-water system has several potential advantages, such as the use of oil soluble chemical reagents, minimizing evaporation of the aqueous phase, and allowing microfluidic production. Understanding the processes that mediate the interfacial adsorption and assembly of peptoid monolayers at the oil-water interface is thus essential for increasing the functionality and complexity of these materials. The behavior of peptoid monolayers at the carbon tetrachloride-water (CCl4-H2O) interface was investigated by surface specific vibrational spectroscopy and interfacial tension measurements, helping to identify the molecular orientations and intermolecular forces involved in the packing of peptoid chains containing a variety of charge and steric groups, as well as showing that interfacial chemistry plays a key role in nanosheet formation.
Also, I am studying the behavior of sodium dioctyl sulfosuccinate (AOT) at the water/ oil (CCl4) planar surface using vibrational sum frequency (VSF) generation. AOT is an amphiphilic surfactant that is highly soluble in most organic solvents, has a high degree of steric hindrance that gives emulsion stability, and does not require a co-surfactant to give it the ability to form reverse emulsions. Its behavior at a planar oil/water interface will be complementary to the ongoing investigations of AOT reverse emulsions, which are studied by vibrational sum-frequency scattering.
Vibrational sum-frequency scattering probes molecules at the curved oil/water interface; and we’d like to answer the question of whether the behavior changes when going from planar to curved interfaces and if there is a role in the confinement of water. MD/DFT calculations will also be used to assign and identify the orientation of AOT at the planar interface.