Effect of side chain length and crosslinking on the ac conductivity of oligo (ethyleneoxide) comb-branch polymer-salt mixtures

Linear and crosslinked comb-branch polymers have been prepared from the macromonomers CH₂ = CH-O-(CH₂CH₂O)nCH₃ where n=3, 5, and 6 7. Comparable ionic conductivity levels could be achieved in both linear and branched system when mixed with several salts, if the crosslink density was kept ~5%. The conductivity-temperature behaviour for the crosslinked systems mixed with LiClO₄, LiSO₃CF₃, LiBF₄ and NaClO₄ was examined as a function of the length of the oligo (ethylene oxide) side chain. It was found that the maximum conductivities of s=10^-4-1.58×10^-3 for T=303-373 K were achieved when n=5 for a 5% crosslinked sample mixed with LiClO₄ at the composition [Li⁺] [EO]=0.05. © 1990.