A System of Aqueous Electrolyte Gels Exhibiting Double Glass Transitions and High Conductivities

Author(s):

Michael S. Ding, Arthur V. Cresce, and Patricia M. Gonzales

Abstract:

We characterized and studied a system of polymer-supported aqueous electrolytes containing a series of gels that exhibited double glass transitions and high conductivities. These electrolytes, composed of a 12-m aqueous solution of lithium bis(trifluoromethanesulfonyl)imide and a monomer of poly(ethylene glycol) diacrylate (PDA), were characterized, both before and after polymerization by ultraviolet irradiation, with thermoconductometry, rheometry, and glass transition analysis. For the gel compositions, the polymerization transformed the starting solution of a single liquid structure into the gel of a polymer-solution double substructure, as evidenced by the emergence of a double glass transition in these gels. Individually, the polymer substructure in the gel gave it a storage modulus that rose rapidly with its PDA content, and the solution substructure, an unusually high conductivity. The generation of a polymer substructure in a gel also made the remaining solution substructure more conductive and less viscous, resulting in conductivity gains upon polymerization and in other unusual phenomena. The coexistence in the gel of two substructures, separately responsible for its mechanical and electrical properties and amenable to alterations in chemical composition and materials processing, holds great interest and promise for future electrolyte development.