Highly Conducting Lithium Polyelectrolytes Based on Maleic Anhydride−Styrene Copolymers

Comblike polyelectrolytes comprising immobilized carboxylic anions and poly(oxyethylene) (OCH 2 CH 2 ) n side chains of various length were obtained from the reaction of appropriate lithium alcoholates with maleic anhydride−styrene alternating copolymers. These materials may be fabricated as films of ambient temperature conductivity in the range of 10 -9 −10 -6 S·cm -1, depending on the side-chain length. The conductivity values increase by 2−3 orders of magnitude after the addition of strong polar plasticizers such as dimethyl sulfoxide and propylene carbonate. A further increase in conductivity was observed after the complexation of carboxylic anions by BF 3 . On the basis of 13 C NMR studies and 7 Li NMR relaxation times of lithium carboxylates, it was found that the anion complexing agent reduces ion pairing in polyelectrolytes more effectively than cation-solvating solvents. The possible conduction mechanism in the solid and gel polyelectrolytes is discussed.