Ultrafine fiber, ion conductive composite polymer membrane, and method for producing the same

摘要

[PROBLEMS] To provide a fiber having both a nanofiber effect and a polymer alloy effect, and to provide an ion-conductive polymeric membrane having dimensional stability against water absorption while maintaining high ion conductivity. [MEANS FOR SOLVING PROBLEMS] An extrafine fiber characterized in that the diameter of single fibers is not more than 1 µm, and a plurality of fibers having a diameter which is smaller than the diameter of the single fibers are contained within the single fibers. An ion-conductive composite polymeric membrane comprising nanofibers formed of an ion exchange group-containing polymer A, which has high chemical stability and high proton conductivity, dispersed, on a nanolevel, in a matrix phase of an ion exchange group-free polymer B which is incompatible with the polymer A, is meltable, and is highly mechanically and chemically stable.