Intial investigations of ionically conductive polymers were principally focused
on poly(ethylene oxide), PEO. PEO can dissolve at room temperature in many
common solvents such as acetonitrile, dichloromethane, carbon tetrachloride,
tetrahydrofuran and benzene. The strong interaction between high-molecular-weight
PEO and inorganic salts was first reported more than 20 years ago (Fenton et al.,
1973), and it is now know that PEO can solvate a wide variety of salts, even at very
high salt concentrations. The solvation of salts occurs through the association of the
metallic cations with the oxygens in the polyether backbone (Figure 2.4). The
solvated ions can be quite mobile in the polymeric solvent, and thus give rise to
significant bulk ionic conductivities.