ChE Seminar – “Decoupling Ion Transport and Modulus in Polymeric Ionic Liquids” by Gabriel Sanoja
Polymeric ionic liquids (i.e. PILs) are single ion-conducting materials that exhibit the thermal and electrochemical stability of ionic liquids and the mechanical properties of polymers. Although PILs are exciting for a variety of applications in energy conversion and storage, the tradeoff between mechanics and conduction remains an important limitation in materials design. Herein, we present dynamic polymer networks based on metal-ligand coordination as promising materials toward this aim. We will examine the effect of the nature and concentration of dynamic ionic crosslinks on the modulus and ionic conductivity of a model poly[(ethylene oxide)-stat-(allyl glycidyl ether)] functionalized with tethered imidazole ligands. We will demonstrate that there is an optimum ionic conductivity due to the competing effects of increasing ion concentration and decreasing ion mobility, with further stiffening enabled by changing the crosslink chemistry without detrimental effects to the ionic conductivity. Finally, we will present some open questions and future directions on the field of ion-conducting polymers.