MOLECULAR COMPOSITES FROM RIGID-ROD POLY(P-PHENYLENE)S WITH OLIGO(OXYETHYLENE) SIDE-CHAINS AS NOVEL POLYMER ELECTROLYTES

The preparation of new poly(p-phenylene)s with oligo(oxyethylene) side chains is reported. The solid state structure of the polymers as well as that of their mixtures with either lithium triflate or lithium bis (trifluoromethanesulfone)imide is described as a molecular composite c onsisting of rigid main chains embedded in a matrix of side-chain segm ents or side-chain/salt mixtures. DSC and temperature-dependent X-ray scattering prove that the side-chain matrix in the pure polymers and p olymer/salt mixtures is completely amorphous. Room-temperature conduct ivities of more than 10(-6) S/cm are obtained in some of these solid p olymer electrolytes. Plasticization of the materials with oligo(ethyle neglycol)-dimethylether (OEGDME) improves the conductivity up to 5.10( -5) S/cm. The stiff polymer backbone induces a high mechanical plateau -modulus in the temperature range between 0 and 90 degrees C, which is of considerable importance for potential applications of these molecu lar composites as separators in rechargeable solid state lithium cells .