Dynamics of Precise Ethylene Copolymers and Ionomers Using Dielectric Spectroscopy

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TECHNICAL SUMMARY:This project will explore the fundamental dynamics of a new class of polymer system: copolymers with monodisperse ethylene sequences between very precisely spaced acid (or ionic) functionalities. Motivated by the recent synthesis and self-assembly of poly(ethylene-acrylic acid) [PEAA] precise copolymers and ionomers this study will focus on the comprehensive investigation of polymer and ion dynamics of these novel materials using primarily broadband dielectric spectroscopy. Recent findings demonstrate that these materials exhibit considerably less heterogeneity than traditional ethylene-based copolymers with randomly placed functionality. Significantly narrower dielectric relaxations are anticipated, making these ideal model materials for the fundamental study of polymer dynamics. The role that highly regular self-assembly of ionic domains has on ion transport will be investigated in order to determine whether precise ethylene ionomers offer a unique route to mechanically robust, yet highly conductive, solid polymer membranes. As there is an intimate connection between phase-separated microstructure and molecular dynamics, a thorough understanding of the nanoscale structure of the precise ethylene copolymers and ionomers is required. Consequently, an important component of this project involves collaborations with other institutions on morphological and moedling aspects of these new materials.NON-TECHNICAL SUMMARY:This project focuses on the systematic investigation of polymer and ion motions in a new class of molecularly precise polymeric materials. The study will also enhance the basic understanding of ion transport in solid polymers, of interest for the next generation of membranes for lithium ion batteries, actuators, and other potential applications. Ethylene-based polymers are of strategic industrial importance, representing the largest class of commercial polymers. As this project is the first to investigate polymer and ion motions of precise ethylene-based acid copolymers and ionomers, it will assist in evaluating the commercial potential of these new materials.The project will create learning opportunities for graduate and undergraduate students, the latter participating through senior thesis projects or as part of the NSF-REU Program at Penn State on soft materials. Program participants will engage in outreach activities, particularly those connected with Penn State's Women in Science and Engineering Institute.