Almost everyone has experienced the disappointment that comes along with the first scratch on a new car, a freshly painted wall, or a just-out-of-the-box cell phone. But what if that scratch were just a temporary thing? What if the car or wall or phone could repair itself and no one would ever know the scratch had been there? If Dominik Konkolewicz has anything to do with it, that fantasy may one day become reality.
Konkolewicz, an assistant professor of chemistry and biochemistry at Miami University, recently received a CAREER grant from the Faculty Early Career Development program of the National Science Foundation (NSF).
The NSF CAREER grant is one of the organization’s most prestigious awards in support of junior faculty who “exemplify the role of teacher-scholars through outstanding research, excellent education, and the integration of education and research within the context of the mission of their organizations.”
Konkolewicz is the ninth scientist at Miami to be awarded a CAREER grant. He and his group will receive $600,000 of funding over five years for his research program on polymers. This award brings the number of currently active CAREER grants at Miami to two.
“If you look around a room, and you remove the air, metals, ceramics, and the small amount of water, just about everything else is a polymer,” Konkolewicz says.
Polymers can be natural or synthetic. Natural polymers include cellulose, which is the main component of wood and paper, and proteins or DNA that are essential for life processes. Among the dozens of commodity synthetic polymers are polyethylene milk jugs and plastic wrap; polystyrene packing materials; polyvinylaacetate (PVA) and epoxy glues; and PET soda and water bottles. Polymers are also included as components of paints and other coatings used to finish surfaces like those of cars, walls, and cell phones.
From a chemistry perspective, polymers consist of smaller molecules, or repeating units, linked together to form a larger molecule. This larger molecule, or macromolecule, is like a necklace, with dozens to tens-of-thousands of smaller molecules making up the individual links. In many useful materials, such as cured epoxy glue, soft contact lenses, and the rubber used in tires, long polymer chains are linked to form a mesh or network-like structure at the molecular level.
“The links that bind these chains together are a little like staples,” Konkolewicz says. “They’re permanent. When a material becomes damaged or fractured, the material becomes useless because there’s no way to recover the original properties.”
Konkolewicz’s work focuses on creating links between the chains that he says are more like paper clips than like staples, ones that can be reused many times. If one link is damaged, it can be exchanged for another one, allowing the material – whether it’s wall paint or a truck tire – to heal itself when scratched or punctured.
Konkolewicz says the tradeoff in this kind of chemistry, since it was pioneered in the late 1990s and early 2000s, has been between dynamism and stability. The types of “paper clips” used to hook units together would either allow a material to recover its original properties very quickly, or allow it to maintain its original shape over time, but typically not both.
To understand this tradeoff, we can think about truck tires. If they were made out of a material that could heal quickly when punctured by a nail picked up on the road, drivers could avoid the time, expense, and hassle of being stuck with a flat. However, if that same highly dynamic material were also highly unstable, the tires would lose their shape as they were squeezed between the truck and the road. That’s exactly the dilemma Konkolewicz says currently exists in this type of materials science.
His innovation is to introduce two different types of links in the same material. One type of link would allow the material to heal itself quickly, while the other – which would be activated by applying heat, pH, or light – would “lock in” the permanent shape. In the case of truck tires, that means they could both recover from a nail puncture and remain perfectly round.
Another consideration Konkolewicz says is important in materials science is toughness, or the ability to withstand seemingly minor damage. Once a brittle material acquires a small chip or other defect, any little bump could cause it to shatter. Konkolewicz says the types of dynamic bonds that he is using can increase material toughness, extending the useful lifetime of products made from those materials.
Konkolewicz’s work has clear implications for sustainability. “If you don’t need to throw something out over time, if something has a longer lifetime, that’s a huge benefit,” he says. “It’s a much smaller drain on resources.”
Konkolewicz currently supervises eight graduate students and has 11 undergraduates on his team. He has also mentored an additional graduate student who has since graduated. These students work with Konkolewicz on his CAREER project, as well as on his other projects involving conjugation of synthetic materials to enzymatic proteins and development of light driven chemical and polymerization processes.
All NSF CAREER projects include an integrated education objective. Konkolewicz will conduct community-based STEM outreach for K-12 students in collaboration with Dayton Public Schools and the Public Library of Cincinnati and Hamilton County. In addition, he will continue developing innovative activities to use in the undergraduate classroom. For example, he plans to expand a pilot project in which students use YouTube as a forum to reflect on how they overcame challenges in their studies and to share these strategies with their peers. The CAREER grant will also provide funds for a student from underrepresented groups to work in Konkolewicz’s lab each summer.
Konkolewicz received his doctorate from the University of Sydney in 2011 and was a visiting assistant professor/senior research chemist at Carnegie Mellon University from 2011 to 2014.
Written by Heather Beattey Johnston, Associate Director of Research Communications, Office for the Advancement of Research and Scholarship, Miami University.
Photos by Jeff Sabo, Miami University Photo Services.