Department of Mechanical Engineering 2019 Spring Seminar Series: Class 530.804
Control of Reaction Fronts for Rapid Energy-Efficient Manufacturing of Multifunctional Polymers and Composites
Presented by Professor Nancy R. Sottos
Department of Materials Science and Engineering &
The Beckman Institute for Advanced Science and Technology
University of Illinois at Urbana Champaign
Reaction-diffusion processes are versatile, yet underexplored methods for manufacturing that provide unique opportunities to control the spatial properties of materials, achieving order through broken symmetry. The mathematical formalism and derivation of equations coupling reaction and diffusion were presented in the seminal paper by Alan Turing [Phil. Trans. R. Soc. Lond. B 237, 37,1952], which describes how random fluctuations can drive the emergence of pattern and structure from initial uniformity. Inspired by reaction-diffusion systems in nature, this talk describes a new manufacturing platform technology predicated on the exploitation of an autocatalytic (self-propagating) polymerization reaction occurring in a system undergoing reaction and diffusion of its ingredients. The system uses the exothermic release of energy to provide a positive feedback to the reaction. In turn, this stimulates further exothermic energy release, and a self-propagating reaction “front” that rapidly moves through the material – a process called frontal polymerization. The self-sustained propagation of a reaction wave through the material gives rise to entirely new ways of manufacturing high performance composites using rapid, energy efficient methods at greatly reduced costs, including 3D printing of thermosetting polymers and composites. Controlling the reaction wave by simple thermal perturbations gives rise to symmetry breaking events that can enable complex, emergent pattern formation and control over growth, topology, and shape.
Nancy Sottos is the Donald B. Willet Professor of Engineering in the Department of Materials Science and Engineering and the Beckman Institute at the University of Illinois Urbana-Champaign. Sottos started her career at Illinois in 1991 after earning a Ph.D. from the University of Delaware. Her research interests include self-healing polymers and advanced composites, mechanochemically active polymers, tailored interfaces and novel materials for energy storage. Sottos’ research and teaching awards include the ONR Young Investigator Award, Scientific American’s SciAm 50 Award, the Hetényi Best Paper Award in Experimental Mechanics, the M.M. Frocht and B.J. Lazan Awards from the Society for Experimental Mechanics, the Daniel Drucker Eminent Faculty Award, an IChemE Global Research Award and the Society of Engineering Science Medal. She is a Fellow of the Society of Engineering Science and the Society for Experimental Mechanics.