Evidence of inter-action between anion and polyether in the bulk

Poly(ethylene oxide) (PEO) derivatives having a positively-charged group on the chain end were prepared to analyze anion conduction mechanism in the polyether moiety. Effects of the terminal group structure and anion species on the anionic conductivity were analyzed. The anionic conductivity of PEO-onium salts was about 10(-4) S cm(-1) at room temperature, which was much higher than that for corresponding cation conductors. This difference should be based on much weaker interaction force of ether oxygens toward anions than that for cations. The ionic conductivity was evaluated under the same segmental motion by normalizing the different glass transition temperature (T-g). As a result, reduced ionic conductivity was nearly equal among all kinds of anion and cation conductive PEO oligomers having charged group on the chain end. The T-g was revealed to mainly govern the ionic conductivity of the matrix. Since the interaction between anion and ether oxygen was certainly detected but it was weak to suppress the elevation of T-g, lower T-g and corresponding high ionic conductivity were observed in these anion conductive polyethers. (C) 2000 Elsevier Science Ltd. All rights reserved.