IONIC-CONDUCTIVITY AND ORGANIZATION OF MACROMOLECULAR POLYETHER ALKALI-METAL SALT COMPLEXES

The ionic association, ionic conductivity and macromolecular organisat ion of alkali-metal salt complexes with poly(ethylene oxide) (PEG) and related polymers are described. The amorphous phase is the principal pathway for ionic mobility in PEO and two regimes of salt concentratio n, polymer-rich and salt-rich, may be identified. Most attention so fa r has been paid to the former, where a better understanding of the sta te of aggregation of the salt and the mechanism of ion transport are c urrent aims of research. The salt-PEO association gives rise to helica l chain conformations in which the cations are enclosed and the anions stack alongside. Extensive macromolecular organisation into domain or fibrous textures may occur in particular systems and the stacking of radical anions such as tetracyanaquinodimethanide form electronically conducting systems. Premelting transformations involving ionic motion in the organised phase give rise to liquid-crystalline behaviour in sy stems with aromatic anions. The organisation and ionic conductivity of novel smectic liquid-crystalline polymer electrolytes are described.