IONIC-CONDUCTIVITY AND DIELECTRIC-PROPERTIES OF POLY(ETHYLENE OXIDE) GRAFT-COPOLYMERS END-CAPPED WITH SULFONIC-ACID

Both anions and cations are mobile and carry the electrical charge in most polymer electrolytes. A single ion conductor with purely cationic conduction can be realized by incorporation of the anion into the pol ymer chain. In order to obtain pure lithium ion conductors we prepared two types of graft copolymers, namely poly(amide 12-graft-ethylene ox ide) and poly(ethylene-co-vinyl alcohol-gr aft-ethylene oxide), respec tively, and end-capped the poly(ethylene oxide) grafts with sulfonic a cid groups. Lithium salts of the graft copolymers were made by neutral izing the sulfonic acid groups with lithium hydroxide. Films of the ne utralized polymers were prepared by solution casting. The thermal prop erties of the films were evaluated from DSC measurements. Complex impe dance spectroscopy gave information on the ionic conductivity and diel ectric relaxations. The highest conductivity, at 80 degrees C, 210(-5 ) S/cm was obtained for poly(amide 12-graft-ethylene oxide). (C) 1998 Published by Elsevier Science Ltd. All rights reserved.