(15f) Understanding Structure-Property Relationships for Complex Fluid-Fluid Interfaces

Postdoctoral Researcher:Georgetown University Department of Physics and National Institute of Standards and Technology

Research Interests: Material-material interfaces are everywhere around us and understanding how to control and modify them is at the center of many current research problems, from formulating laundry detergents to creating highly efficient photovoltaic solar cells. My research interests primarily revolve around studying how to create, stabilize, and modify these interfaces; with particular interests in surfactant adsorption, emulsion and foam stabilization, nanoparticle dispersions/composites, and nanoparticle assembly at fluid-fluid interfaces. Throughout my career I have both gained experience using a variety of characterization techniques and made valuable contacts at national labs and industrial R&D departments which, when combined, provide me with an excellent foundation to build a research career upon.

Successful Proposals: ADNOC-OSC 2-year Research and Development Grant

Postdoctoral Project: â??Developing Measurements of Structure-Property Relationships for Complex Fluids in Extreme Environments.â?

Under supervision of Steve Hudson (NIST, Mat. Sci. and Eng. Division), Daniel Blair (Georgetown, Dept. of Physics), and Katie Weigandt (NIST, Center for Neutron Research)

PhD Dissertation: â??Metal Oxide Nanoparticles: wettability modification for emulsion stabilization and electrostatically induced gelationâ?

Under supervision of Jeffrey H. Harwell, Chemical, Biological and Material Engineering, University of Oklahoma

Research Experience: My scientific research journey has introduced me to a wide variety of different topics within the realm of colloid and interface science. During my undergraduate career, I worked as a research assistant in OUâ??s Applied Surfactant Lab (ASL), which balanced industrially-sponsored research projects with more academic grant-funded research. Over my time in the ASL, I worked on a variety of different projects including: formulating a high performance â??greenâ?? hard surface cleaner with SC Johnson, investigating the competitive adsorption of surfactants and polyelectrolytes on metal oxide nanoparticles, optimizing nanoparticle propagation in oil reservoir rock with the Advanced Energy Consortium, developing ultra-low interfacial tension surfactant blends for use in a variety of environmental remediation applications, improving performance of erasable inks with Papermate, and incorporating polyelectrolytes into detergent formulations with Clorox. My graduate research was completed as a member of the Center for Interfacial Reaction Engineering with funding from a DoE-EPSCoR Grant. I modified the surfaces of nanoparticles and used them to stabilize Pickering emulsions; investigating how the surface modification alters the emulsion properties. Additional work studying interactions between oppositely charged nanoparticles dispersed in water using microscopy, small-angle scattering, and rheology rounded out my graduate studies. This wide range of experience has left me with a broad understanding of the current state of academic and industrial research in the field of colloids and surfactants.

Teaching Interests : Throughout the course of my graduate and post-graduate work I have had several opportunities to gain hands-on teaching experience. During my first year of graduate school I was given opportunities to act as a guest-lecturer and TA in undergraduate-level laboratory courses. Then, during fall semesters throughout the remainder of my graduate studies, I was asked to act as the Instructor of Record for a section of a First-Year Engineering Experience course in OUâ??s College of Engineering, for which I was awarded an Outstanding Graduate Assistant Teaching Award. As faculty I would be interested in teaching a wide variety of courses and would be excited to teach any course. Specific interests would include materials, fluid mechanics, thermodyanamics, and colloids/surfaces focused courses.

Proposed Future Research: As a faculty member, my research philosophy would rest on the belief that the best way to maintain a well-funded, relevant set of research goals is to strike a balance between basic scientific research that may or may not be of immediate commercial relevance and industry-funded research/consulting projects. Combining these two goals can be difficult, but I believe it is the best way to stay up to date with the cutting edge of academic research while simultaneously anticipating industry needs, which are often an excellent indicator of future research directions in engineering fields. I also believe in using a diverse group of researchers in terms of experience levels; using undergraduates, graduate students, and postdoctoral researchers to maximize the productivity of the research group, as a whole. In particular, I believe bringing in researchers from other STEM majors or creating opportunities for interdepartmental collaboration can help solve problems far more synergistically than can occur when all of the students and faculty involved are approaching the research problem from a similar background.

Scientifically, I plan to focus my research on studying how interfacial properties alter bulk performance in three different applications:

• Nanoparticle stabilized foams - How do interparticle forces, particle morphology, and surface modifications affect foam properties like stability, bubble size, and rheology
• Structure-property relationships in bicontinuous microemulsions - linker molecules are used to modify the interfacial rigidity of microemulsions and alter coalescence time, neutron scattering techniques and rheological measurements can be used to determine how changes in interfacial morphology and dynamics affect kinetics of emulsion coalescence
• Membranes via emulsion polymerization - Developing a technique to produce nanoporous membranes via polymerization of bicontinuous emulsions where the monomer is used as the organic phase could allow for greater control and tunability of pore size distributions and pore densities

Selected Publications:

• JS Weston, RE Jentoft, BP Grady, DE Resasco, and JH Harwell. "Silica Nanoparticle Wettability: Characterization and Effects on Emulsion Properties," Industrial & Engineering Chemistry Research, DOI: 10.1021/ie504311p, 2015.
• JS Weston, D Venkataramani, CP Aichele, BP Grady, JH Harwell, and DE Resasco. â??Pseudosolid, Shear-Thinning Gel Formation in Binary Dispersions of Metal Oxide Nanoparticles at Low Volume Fractions,â?Â Langmuir, 30 (49), 14982, 2014.
• JS Weston, JH Harwell, B-J Shiau, and M Kabir, â??Disrupting admicelle formation and preventing surfactant adsorption on metal oxide surfaces using sacrificial polyelectrolytes,â?Â Langmuir, 30 (22), 6384-6388, 2014.
• N Briggs, JS Weston, B Li, D Venkataramani, CP Aichele, JH Harwell, and S Crossley. â??Multiwalled Carbon Nanotubes at the Interface of Pickering Emulsions,â? Langmuir, 31, 13077, 2015.