POE incorporation into ionic clusters of ionomer and ion‐conduction behaviors

Poly(oxyethylene) (POE) was incorporated into the ionic clusters of ionomers, ethylene and methacrylic acid (7.2% neutralized with KOH) copolymer membrane. The changes of properties were studied from SAXS, DSC, IR and ionic conductivity. The IR study suggested that the coordinated structures in ionic clusters of the membrane were destroyed by POE incorporation, and also SAXS suggested that ionic clusters were swollen by POE incorporation. The ionic conductivity, a carrier being K⁺ in this system, increases from 10⁻¹⁶ S/cm to 10⁻⁹ S/cm at 30°C by the incorporation of POE (20.5 wt%). On the other hand, a large amount of POE (63 wt%) could be incorporated into ionomer membrane by the esterification of methacrylic acid groups (93%) with POE. When LiClO₄ was added, ionic conduction occurred in the phase‐separated POE domain, which had a low glass transition temperature (−55.2°C), showing an ionic conductivity 2.6 × 10⁻⁶ S/cm at 25°C.