This research has as its aim the synthesization and study of the solid-state properties of homogeneous ion-conducting polymer- electrolyte complexes as well as composites of polymers with heavy metal, radiopacifying salts. The project focuses on two broad objectives: 1) the synthesis, mechanism of formation, and characterization of comb-like homopolymers and block copolymers of polysiloxanes and other polymer with oligo-oxyethlene side chains, including those in which the anion of the conducting salt is covalently bound to the polymer, and 2) the synthesis of homogeneous polymer-salt complexes or mixtures in which the salt is added either to effectuate ion-conduction or to impart radiopacity to the polymer. The properties of these polymer- salt composites will be studied by a variety of techniques including FTIR, NMR, small-angle X-ray scattering, electron microscopy, differential scanning calorimetry, conductivity, and radiology. The investigations are designed to clarify relationships between the ionic conductivity or radiopacity of the polymer-salt composites and their morphology, to evaluate salt effects on mechanical properties and to determine how polymer-salt compatibility is affected by interionic and ion- polymers interactions. The solvent-free polymer electrolyte complexes are potentially useful as flexible, plastic electrolytes in rechargeable solid- state alkali batteries. Resins in which heavy-metal salts are solubilized or immobilized on the polymer matrix are of importance in the development of X-ray contrast or radiopaque materials useful in applications such as dental resins, medical implants, or plastic fireweapons where rapid imaging is important.