Effect of molecular weight and salt concentration on conductivity of block copolymer electrolytes

Ashoutosh Panday, Scott Mullin, Enrique D. Gomez, Nisita Wanakule, Vincent L. Chen, Alexander Hexemer, John Pople, Nitash P. Balsara

Research output: Contribution to journalArticlepeer-review

283 Scopus citations


The ionic conductivity, σ, of mixtures of nearly symmetric polystyrene-block-poly(ethylene oxide) copolymers and Li[N(SO 2CF 3) 2] (LiTFSI) salt was measured as a function of molecular weight, salt concentration, and temperature. The molecular weight of the polyethylene oxide) block, M PEO, was varied from 7 to 98 kg/mol. The molar ratio of lithium to ethylene oxide, r, was varied from 0.02 to 0.10. In general, σ increases with increasing M PEO for all values of r. The data can be summarized by plots of normalized conductivity, σ n, versus M PEO, where σ n = σ/fφ PEOσ PEO), φ PEO is the PEO volume fraction in the copolymer, σ PEO is the conductivity of PEO homopolymer, and f is a morphology-dependent factor set equal to 2/3 for our lamellar samples. The temperature-dependent conductivity data at a given salt concentration collapse onto a single curve when plotted in this format. At r = 0.085, σn values reach a plateau in the vicinity of unity in the high M PEO limit. At other values of r, σn continues to increase with M PEO within the experimental range and reaches a value of around 0.5 in the high M PEO limit.

Original languageEnglish (US)
Pages (from-to)4632-4637
Number of pages6
Issue number13
StatePublished - Jul 14 2009

All Science Journal Classification (ASJC) codes

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry


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