Characterization of ion-exchange membranes prepared by ion irradiation graft polymerization method

Goto, Mitsuaki*; Yamaki, Tetsuya; Koshikawa, Hiroshi; Sawada, Shinichi; Kitamura, Akane; Higa, Mitsuru*

We have exploited a grafting technique with heavy-ion beams to create ion exchange membranes for various practical applications such as fuel cells and water desalination systems. In this study, instead of styrene that is a common monomer, sodium styrene sulfonate (SSS) was for the first time employed for this so-called ion-track grafting. A 25 m-thick poly(vinylidene fluoride) film was bombarded with 560 MeV Xe at a fluence of 3.010 or 1.010 ions/cm, and subsequently immersed in a SSS grafting solution at 60C. The charge density was estimated through the measurement of the membrane potential in an aqueous solution of potassium chloride. Our membranes exhibited higher charge density than the conventional or commercially-available samples probably due to track structures characteristic of the bombarding heavy ions.