Synthesis of anion receptor grafted siloxane polymers and the ionic conductivity studies of polymer-salt complexes

A new type of ionic conducting polymers has been synthesized by grafting anion receptors on siloxane polymer backbones. The polymer electrolytes were formed by complexing these polymers with LiCl salt. The room temperature conductivity is in the range of 7 X 10(-8) to 4 X 10(-6) S cm(-1) and depends on the structures of grafted anion receptors and the polymer backbones. These values are close to the conductivities of poly(ethylene oxide)-based polymer electrolytes. The temperature dependence of the ionic conductivity of these polymer electrolytes was also studied. The unique feature and an interesting point of this new type of polymer electrolytes is that the ion complexation is formed between the attached anion receptors and the anions, and there are no ethylene oxide groups in these polymers. The anion receptors are based on aza-ether structures with electron-withdrawing groups attached on them. In contrast to this, in poly(ethylene oxide)-based electrolyte systems, the complexation is formed between the oxygen atoms in the ethylene oxide groups of the polymer and the cations. The complexation between the anion receptors and anions in this new type of polymer electrolytes was confirmed by near edge X-ray absorption fine structure spectra. (C) 1999 The Electrochemical Society. S0013-4651(98)06-081-9. All rights reserved.