MRL MVPs: Chris Evans

Although he shares a moniker with the beloved Captain America actor, University of Illinois Urbana-Champaign’s own Chris Evans’ strength is materials science. He joined the Materials Science and Engineering (MatSE) department in 2016, making an impact in the field of polymer science. Also a member of the Materials Research Laboratory (MRL), he’s been doing exciting work to make polymers that are easier to recycle and that have valuable new functionalities.

It's a small world

Beginning his academic journey in his home state, Evans attended the University of Minnesota for his undergraduate degree, starting out as a music performance and mechanical engineering double major. Ultimately deciding that those majors weren’t for him, he transitioned to chemistry and chemical engineering.

Time spent doing undergraduate research ultimately shaped Evans' interest in polymer chemistry and helped set him on his path to graduate school. “I worked with a postdoc who introduced me to his graduate advisor," Evans says. "I ended up working with that same graduate advisor at Northwestern University. It’s a small world.” Halfway through graduate school, he began to consider going into academia and after graduating, started a postdoc position first at the University of California, Berkeley and then moved to the University of California, Santa Barbara.

With degrees in chemical engineering, Evans initially pursued faculty positions in chemical engineering before finding an open position at UIUC in the MatSE department. He says, “It’s a fantastic department. I was very excited to have gotten an interview and even more excited to be offered the position.” Working in the field of materials science and engineering ended up being a better fit than chemical or mechanical engineering. He says it combines chemistry and physics skills, and a little bit of mechanical intuition and measurements.

Dynamic chemistry

The Evans research group focuses on experimental polymer science. One main area of their research is the development of polymers that are easier to reprocess and recycle. Some polymer-based things like rubber bands and tires are not recyclable: they cannot be melted down and reused like other polymers. With the goal of making sustainable, and possibly even self-healing, polymers, the Evans group is putting chemical bonds into polymers that can swap between molecules at high temperatures, but not at low temperatures.

“We design materials, synthesize them, and then characterize their properties and see if we can make connections between the molecular scale and the macroscopic properties that we are interested in using,” Evans explains.

Further, they’re using the same kinds of dynamic bonds to impart functionality. They use the motions of bonds to help with the transport of molecules and ions through polymers, which is important for applications like membranes, water filtration, and movement of charge through a battery.

Although they’re focusing on recyclability and sustainability-a hot topic in polymers-Evans says, “what sets our group apart is that we also use the dynamic chemistries for other non-recyclable reasons.” That includes adding dynamic bonds to improve the performance of battery electrolytes, membranes, and even adhesives of 3D printed polymer materials- applications that are complementary to recycling.

Biomaterials are a new area of research in the Evans group. The goal is to make polymers that use peptides inspired by nature rather than using synthetic strands that are petroleum-based. They ideally want to make helical peptides that can conduct ions, and then to make flexible reconfigurable networks out of the peptides for use in batteries, electrolytes, and membranes, potentially offering improved stability and make it easier to degrade back into amino acids.

Pioneering new research

Evans shares that one of his biggest career highlights so far has been graduating multiple students who have gone on to “bigger and better things” and have gotten positions that are well-suited to their goals. Another highlight has been pioneering new directions for dynamic networks. His group has explored dynamic networks for applications such as battery electrolytes and ultra-thin coatings; furthermore, since they published a paper on some of their work in this area, other research groups have taken up the subject. Evans says, “we are excited to see what the future holds for research that might be based on some of these concepts of dynamic bonded networks.”  

Despite the many competing demands on his time, Evans is always excited to talk with his students about their research and work on new projects with them. “It’s fun to see a paper coming together,” he says. “It’s rewarding to have a student and see that it clicks in their head. Maybe they didn’t quite appreciate what the significance was until they started writing and plugging things into the context of the literature, and they see that they really are doing new things-not just a derivative project, but actually pioneering new work.”

Looking ahead to the future, Evans would like to focus more on sustainability. “Our insights could be useful to designing sustainable polymers,” he says. Although his group’s research currently focuses more on basic physics, some of this work is translating into products and bio-inspired materials research. He sees a lot of potential for exciting polymer science that could lead to more environmentally benign materials if they were to be based on biomolecules as opposed to petrochemical derived plastics.