Imidazolium-Containing ABA Triblock Copolymers as Electroactive Devices

Evan Margaretta, Gregory B. Fahs, David L. Inglefield, Chainika Jangu, Dong Wang, James R. Heflin, Robert B. Moore, Timothy E. Long

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


Two-step reversible addition-fragmentation chain transfer (RAFT) polymerization and two subsequent postpolymerization modification steps afforded well-defined ABA triblock copolymers featuring mechanically reinforcing polystyrene outer blocks and 1-methylimidazole-neutralized poly(acrylic acid)-based central blocks. Size exclusion chromatography and 1H NMR spectroscopy confirmed predictable molecular weights and narrow distributions. The ionic liquid (IL) 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([EMIm][OTf]) was incorporated at 30 wt % into polymeric films. Thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis determined the thermomechanical properties of the polymers and polymer-IL composites. Atomic force microscopy, small-angle X-ray scattering (SAXS), and transmission electron microscopy (TEM) determined surface and bulk morphologies, and poly(Sty-b-AA(MeIm)-b-Sty) exhibited a change from packed cylindrical to lamellar morphology in SAXS upon IL incorporation. Electrochemical impedance spectroscopy determined the in-plane ionic conductivities of the polymer-IL membranes (μ 10-4 S/cm). A device fabricated from poly(Sty-b-AA(MeIm)-b-Sty) with 30 wt % incorporated IL demonstrated mechanical actuation under a low applied voltage of 4 V.

Original languageEnglish (US)
Pages (from-to)1280-1288
Number of pages9
JournalACS Applied Materials and Interfaces
Issue number2
StatePublished - Jan 20 2016
Externally publishedYes


  • block copolymers
  • controlled polymerization
  • electromechanical actuators
  • ionic liquids
  • self-assembly

ASJC Scopus subject areas

  • General Materials Science


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