(7hp) Controlling and Characterizing Complex Fluid-Fluid Interfaces

Controlling
and Characterizing Complex Fluid-Fluid Interfaces

Javen
S. Weston

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. My
experience provides me with an excellent foundation for a productive research
career by combining experience using a variety of characterization techniques
with valuable contacts and collaborators at national labs and industrial
R&D departments.

Successful
Proposals: Co-wrote an ADNOC-OSC
2-year Research and Development Grant ($460,000) and wrote 8 accepted beam time
proposals at three different international scientific user facilities

Postdoctoral
Project: “Developing Measurements of Structure-Property
Relationships for Complex Fluids in Extreme Environments.”

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: “Metal Oxide Nanoparticles: wettability
modification for emulsion stabilization and electrostatically induced gelation”

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

Research
Experience: As a post-doctoral
researcher, I have been helping to develop an apparatus using small-angle
neutron scattering to simultaneously measure the rheology and structure of
complex fluids under extreme flow conditions and elevated temperatures/pressures.
The device will eventually be available for use by external users and provide a
powerful new tool for investigating flow conditions relevant to pharmaceutical,
petroleum, coatings, and polymer processing applications. While developing this
device, I have also completed work using neutron scattering to study
shear-induced structures in microemulsions and worm-like micelles.

My graduate research was completed as a
member of the Center for Interfacial Reaction Engineering with funding from a
DoE-EPSCoR Grant. I studied how systematic surface modification alters the
wettability of nanoparticles along with their ability to stabilize oil/water
emulsions. Additional work studying dispersions of oppositely charged
nanoparticles and gels formed by their heteroaggregation was also a part of my
dissertation.

My research experiences introduced me to
a wide variety of different topics within the realm of colloid and interface
science. While an undergraduate, I worked as a research assistant in the
Applied Surfactant Lab (ASL), which balanced industrially-sponsored research
projects with academic grant-funded research. Over my time in the ASL, I worked
on a variety of different projects including: formulating a high performance
‘green’ hard surface cleaner, investigating the competitive adsorption of
surfactants and polyelectrolytes on metal oxide nanoparticles, optimizing
nanoparticle propagation through porous media, developing ultra-low interfacial
tension surfactant blends for use in environmental remediation applications,
improving performance of erasable inks, and incorporating polyelectrolytes into
detergent formulations.

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 OU’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, thermodynamics,
and colloids/surfaces focused courses.

Research
Interests: 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
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 and
provide students with leadership and managerial experience. In particular,
working with undergraduate researchers from other STEM majors, or creating
opportunities for interdepartmental collaboration, can help solve problems far
more synergistically than can occur when all the students and faculty involved
are approaching the research problem from a similar background.

            My research interests revolve around understanding how micro- and
nano-scale interfacial and colloidal forces affect bulk properties of
composites, membranes, emulsions, and complex fluids. My proposed research is
bound together under the theme of “engineered interfaces” with the goal of
being able to generate materials with optimized microstructural and bulk properties for their given
application, while generating generalized relationships that can inform future
material design. Below, are detailed descriptions of two specific research
thrusts:

§  Structure and rheology of complex
fluid-fluid interfaces - Solids-stabilized fluid-fluid
interfaces are encountered in a variety of industrial and practical
environments, such as asphaltene-stabilized emulsions in the oil industry that
can plug pipelines and production wells, or delicious protein-stabilized foams
like whipped cream and mousse. The bulk properties of these fluids are governed
by complex interactions spanning from the nanometer-scale particles to the
micron-scale droplets to the bulk fluid properties. Relatively little work has
been done to generate systematic relationships that tie the microstructural
arrangement of particles and droplets to the bulk properties that are important
in industrial applications

§  Engineering nanoscale structure via
emulsion polymerization - Membrane separations
are becoming increasingly popular in a wide variety of applications such as
municipal water desalination, waste water treatment, and pharmaceutical
purification processes. Current manufacturing methods for these membranes
experience problematic trade-offs between flux and selectivity of the resulting
membrane. Using in situ photopolymerization
of a bicontinuous microemulsion phase could provide a new way to finely tune
the size selectivity of a membrane without greatly diminishing the flux.

My
desire would be to supplement these long-term research thrusts with shorter,
industry-sponsored projects with more immediate practical and commercial goals,
by reaching out to various industry collaborators I have worked with during my
research career.

Selected
Publications:

·     JS Weston, DS Seeman, DL
Blair, PF Salipante, SD Hudson, and KM Weigandt. “A device for simultaneous rheological
and microstructural characterization of complex fluids at extreme shear rates,”
Soft
Matter, Submitted June 2017.

·    
JS Weston, JH Harwell, and BP Grady. “Rheological
characterization of yield stress gels formed via

electrostatic
heteroaggregation of metal oxide nanoparticles,” Soft Matter, Under
revision June 2017

·     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. “Pseudosolid, Shear-Thinning
Gel Formation in Binary Dispersions of Metal Oxide Nanoparticles at Low Volume
Fractions,” Langmuir, 30 (49), 14982, 2014.

·     JS Weston, JH Harwell, B-J
Shiau, and M Kabir, “Disrupting admicelle formation and preventing surfactant
adsorption on metal oxide surfaces using sacrificial polyelectrolytes,” Langmuir,
30 (22), 6384-6388, 2014.

·     N Briggs, JS Weston, B Li, D
Venkataramani, CP Aichele, JH Harwell, and S Crossley. “Multiwalled Carbon
Nanotubes at the Interface of Pickering Emulsions,” Langmuir, 31,
13077, 2015.