PPG-MRL Graduate research assistantships awarded to four students

8/15/2018

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Michael Caple, Larry Salvati, Samya Sen, and Yingfeng Yang have been awarded PPG-MRL Graduate Research Assistantships to pursue cutting-edge research broadly related to the areas of interest to PPG.

PPG and the PPG Foundation aim to bring color and brightness to PPG communities around the world. By investing in educational opportunities, the company and foundation help grow today’s skilled workforce and develop tomorrow’s innovators in fields related to coatings and manufacturing. This student program will bring this color and brightness to the University of Illinois community, with new thought leaders at the Materials Research Laboratory (MRL).

The Research

PPG provided MRL with a $75,000 donation from the PPG Foundation in 2018 to provide funding toward the graduate research assistantship for a second year. “We are very thankful the PPG Foundation provided this gift to the MRL,” MRL Director Paul Braun said.  “Using this gift to both advance the studies of our graduate students and to help catalyze a deep and productive relationship between PPG and the MRL is very exciting… we anticipate wonderful discoveries from these exceptional students as a part of this program.”

PPG and the PPG Foundation aim to bring color and brightness to PPG communities around the world. By investing in educational opportunities, the company and its foundation help grow today’s skilled workforce and develop tomorrow’s innovators in fields related to coatings and manufacturing. Plus, we empower PPG employees to multiply their impact for causes that are important to them by supporting their volunteer efforts and charitable giving. Learn more at www.ppgcommunities.com.

Michael Caple

Michael Caple
Michael Caple
“My research focuses on low-temperature electrodeposition of popular lithium transition metal oxide battery materials via the use of ionic liquids. Low-temperature deposition has the potential to allow for conformal coating of surfaces that are not stable for energy-intensive higher temperature techniques such as slurry casting (700 to 1000 °C) and low-temperature molten salt electrodeposition. The target temperature range for this project is 90 to 200°C.”

Caple’s advisor, Professor Paul V. Braun, an Ivan Racheff Professor of Materials Science and Engineering, describes Caple as “an exceptionally talented Ph.D. student. While only entering his second year of graduate study, he already has a firm grasp of his project, and has demonstrated a depth of understanding more typical of a student getting ready to finish than getting started. With only minimal guidance, shortly after joining my group, he embarked into a new direction on the near room temperature electrodeposition of high quality cathode materials for energy storage, materials that prior to his work had required growth temperatures in excess of 400 degrees Celsius, and is already achieving impressive results.”

Larry Salvati

“I am a second year physical chemistry graduate student working in Dana Dlott's lab. In our lab, we've developed methods for spectroscopically probing small-scale chemical systems in extreme pressure temperature states. Specifically, we use sub millimeter projectiles to generate jump discontinuities in pressure and temperature, referred to as shock compression. The central question of my research is to discover what chemical and physical processes occur under mild and extreme shock compression and how these discoveries help explain material properties under less extreme environments. The driving hypothesis of this research is that there exists an intellectual framework by which shock compression chemistry can predict chemical events occurring under a continuum of pressure-temperature states from ambient pressures to millions of atmospheres. To study this, our group has done extensive research on thin polymer matrices as well as liquid matrices containing various fluorophores and dyes to track how spectroscopic observables evolve over the course of shock compression. We are developing model systems that can be used as a basis by which the chemistry occurring in any thin layer material can be intuited under high-stress environments. Under the PPG-MRL grant, I wish to work towards better understanding degradation mechanisms that occur in coatings such as paints in high-stress applications.”
Larry Salvati
Larry Salvati

Salvati’s advisor, Professor Dana Dlott, a William H. and Janet G. Lycan Research Professor of Chemistry, describes Salvati as “excellent graduate student just beginning his third year in our Chemical Physics program.  Larry led the development of remarkable experiments where he has produced and studied actual realistic shock wave induced detonations in tiny charges of plastic-bonded explosives, and he is working on preparing a high-impact paper on the subject. Larry’s PPG project, Coatings in Extreme Environments, is an outgrowth of his ARO [Army Research Office]  and AFOSR [Air Force Office of Scientific Research] funded PhD work on impact initiation of energetic materials. He has developed a microscope that can produce well-controlled transient conditions of high strain rate, high temperature and high pressure in thin coatings while probing them with the most advanced high-speed optical and optomechanical diagnostics. We believe this will be useful and interesting to PPG as a method of testing by accelerated aging, discovering new phenomena in coatings under extreme conditions and explaining how coating materials respond to harsh or extreme environments.”

Samya Sen

Samya Sen
Samya Sen
“The objective of my research is to understand how fluid rheology determines droplet impact, splashing, and coating phenomena. Of particular interest are thixotropic properties which describe time-dependent breakdown and build-up of material structure, e.g., with colloidal flocs or associating polymers. My approach is to use experimental high-speed video studies of droplet and spray impacts on surfaces, fluid mechanics concepts of dimensionless groups, new methods of rheological characterization and consideration of material microstructure causing the thixotropy. Research in this direction is of significance, for instance, for applications where paint is sprayed onto a surface that has been pre-coated, among numerous other scenarios.

Our aim is to develop a method of characterizing fluids based on their thixotropic nature and advance our understanding of droplet impact dynamics on coated substrates through experimentation. It is important to acknowledge and incorporate thixotropic effects in applications that involve dynamic flow scenarios of complex fluids. Processes that involve fluids passing through different levels of shear and ultimately discharging as sprays or droplets onto a surface to coat it can be improved by understanding the effects of underlying dynamics, both due to the flow conditions and fluid structure. Knowledge of the thixotropic properties and related dynamic flow behaviors (relevant to coating processes) of complex fluids can facilitate appropriate material selection and design, and fluids can henceforth be developed that meet the desired performance standards of a coating without being affected by processing conditions.”

Sen’s advisor, Professor Randy H. Ewoldt, an Associate Professor in the Department of Mechanical Science and Engineering, describes Sen as “Samya is academically ambitious and yet maintains an outstanding GPA, taking a course load beyond that of a typical student and also covering a wide breadth of topics relevant to his research interests. This ranges from molecular perspectives to advanced fluid mechanics courses.

Even while taking extra courses above the typical load in our program, Samya has been very productive with research. It's been less than a year since he started in my group, and yet he has already made significant progress on two separate but complementary studies. Both are relevant to PPG interests in coatings and complex fluids.

Samya's overall objective is to understand how rheologically-complex fluids stick, splash, and coat surfaces upon impact. Even with Newtonian fluids, this is a challenge. But with non-Newtonian fluids, the added rheological complexity requires that material microstructure also be considered (e.g. colloidal flocs, or associating polymers, or high volume fraction emulsions, or microgel particle suspensions), and the mathematical and conceptual description of the macroscopic properties are themselves difficult to describe.

His research includes (i) experimental studies with high-speed video and color interferometry of droplet impacts onto surfaces, and (ii) mathematical analysis of thixotropic shear rheology tests to develop universal model-independent descriptions of this property for comparison across different material microstructures.”

Yingfeng Yang

“My research focus on studying the interesting new applications of hindered polyurea and constructing novel topological structures via hindered urea chemistry,” Yang said. “Polyurea is widely used as coating materials because of its exceptional physical properties such as high durability, moisture insensitivity, temperature tolerance, and chemical resistance. However, because of the extremely fast curing process (reaction between isocyanates and amines can finish within seconds), polyurea coating is usually spray applied only; the more environmentally/user- friendly and sagging-free powder coating is simply not applicable for polyurea. Now with our newly developed dynamic urea chemistry, we can first make cyclic urea precursors; these precursors can further cure and crosslink without extra crosslinker due to the bond dynamicity. Because this curing process is based on dynamic bond exchange and can finish in a reasonable timescale, powder coating of polyurea becomes possible with this method.”
Yingfeng Yang
Yingfeng Yang

 “Yingfeng is an excellent graduate student entering her fourth year in the Ph.D. program,” Yang’s advisor, Hans Thurnauer Professor of Materials Science and Engineering Jianjun Cheng said. “For her research, Yingfeng is exploring what interesting properties our newly developed hindered urea chemistry can bring to this ‘old’ but important class of materials. A small change can make huge differences. We have already demonstrated our hindered polyurea can be used in self-healing materials and malleable thermoset. I am very excited about Yingfeng’s work as part of the PPG fellowship because it offers a different strategy to apply polyurea coating and possibly broadens its applications, which cannot be easily achieved by conventional method.”

“The biggest challenge now falls into the design of the precursors and optimization of the curing condition, which we will spend some time to figure out.” Yang said. “As a PPG-MRL Graduate Research Assistant, I will continue to pursue my research in exploring all those interesting new features of hindered polyurea. Apart from powder coating, polyurea also holds great promise in areas like sacrificial materials, hot-melt adhesives, printable thermosets and so on.”

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This story was published August 15, 2018.