Resistive and Capacitive Behavior in Self-Healing Poly(Ionic Liquid) Copolymers

This thesis elucidates the origin of molecular events during the damage-repair cycle in a new class of copolymers composed of ionic liquids (ILs) and acrylic-based monomers. In these studies, (1-[(2-methacryloyloxy)ethyl]-3- butylimidazolium bis(trifluoromethyl-sulfonyl)imide) (MEBIm-TFSI) was copolymerized with methyl methacrylate (MMA) and n-butyl acrylate (nBA) to form poly((1-[(2-methacryloyloxy)ethyl]-3- butylimidazolium bis(trifluoromethyl-sulfonyl)imide)-co-methyl methacrylate-co-n butyl acrylate) (p(MEBIm-TFSI/MMA/nBA)) and its mechanical and electrical properties were examined. Following the introduction to this work, Chapter 1 provides an overview of the continuously growing field of ILs and focuses on the structure-property relationships between ILs and their properties as single molecules and monomers in poly(ionic liquid)s (PILs). Chapter 2 reviews the applications of PILs in the fields of self-healing, fuel cell membranes, nanoparticles, and porous materials. Chapter 3 outlines the procedures of this work including synthesis and characterization of the imidazolium-based PIL copolymer. Chapter 4 elucidates the origin of self-healing in the context of unique electrical responses that are frequency dependent. Broadband Dielectric Spectroscopy (BDS) is utilized to define this dependence, along with generating characteristic RC circuits that best fit these responses. This chapter proposes the mechanism of self-healing for p(MEBImTFSI/MMA/nBA) utilizing MD simulations. Finally, conclusions and future opportunities in the field of PILs are discussed, along with suggestions for further foundational understanding of the interactions that result from chosen IL monomer structures and their inclusion in dielectric copolymers