CBE Colloquia - The Emergence of Non-equilibrium Dynamic Polymer Networks

Since its inception a century ago, the forefront of polymer science has always evolved around non-crosslinked polymers (thermoplastics), with most major developments centered on how to precisely control the chain structures so to push the limits of the macroscopic material properties. By comparison, crosslinked polymer networks (thermosets) had achieved industrial success before the concept of macromolecule/polymer came into life. Surprisingly, however, major theories/methods on controlling their structures have been notably lacking throughout the history of modern polymer science. The root cause lies in the difficulty on precise control of the polymerization conditions during their synthesis, coupled with the occurrence of gelation during polymerization. Consequently, network structures of crosslinked polymers often correspond to highly disordered equilibrium states, with very limited freedom for structural tuning. This has led to challenges to meet emerging demands for flexible and sustainable manufacturing of high performance polymeric materials. Non-equilibrium states are fundamental to the diversity of nature and offer inspirations for the design of next‑generation materials. Can the concept of non-equilibrium be introduced into crosslinked polymer networks and what unique benefits would this offer in pushing this type of materials beyond their conventional limits? In this talk, I will describe our adventure in this direction, including the origin of the concept of non-equilibrium dynamic polymer networks, its evolution over the years in terms of the molecular design scope, and how this may reshape the landscape of polymer materials.