Professor Evans's award supports this proposal: The elastic modulus and viscosity of a polymer are two of the most important properties for many applications. They are critical to understanding time dependent behavior, and determine the performance of pressure sensitive adhesives, coatings, and damping materials. Conventionally, we have lumped polymers into two categories based on their behavior. Thermoplastics, things like airplane windows or bottles, will show a decrease in both modulus and viscosity when heated. Thermosets and elastomers, such as rubber bands, will exhibit an increasing modulus and never flow even when heated. Getting around these traditional behaviors is critical to designing the next generation of polymeric materials with unprecedented and unconventional responses. Our group is using dynamic networks called "vitrimers" to independently control all of these features which is not possible in traditional thermosets and thermoplastics. The ability to precisely design viscoelasticity in polymers will lead to an unprecedented ability to match material response to a given application.
“Our group is really interested in trying to design new materials which break from the traditional behavior of polymers that have been used from decades,” said Evans. “With dynamic networks, we can also think about new ways of manufacturing and recycling plastics which could lead to more sustainable materials.”
Evans is an Assistant Professor at the University of Illinois Urbana-Champaign working at the intersection of polymer chemistry and physics. His group focuses on tuning molecular aspects of soft materials to understand how they give rise to unconventional properties. Many projects in the group also focus on mass or ion transport in polymer networks to develop next generation materials for energy storage and efficient separations.