title: Imidazolium-Containing ABA Triblock Copolymers as Electroactive Devices.
abstract: 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 (1)H 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 (σ ∼ 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.
authors.affiliation: Department of Chemistry, Macromolecules and Interfaces Institute, and ‡Department of Physics, Virginia Tech , Blacksburg, Virginia 24061, United States.
authors.forename: Evan
authors.initials: E
authors.lastname: Margaretta
authors.affiliation: Department of Chemistry, Macromolecules and Interfaces Institute, and ‡Department of Physics, Virginia Tech , Blacksburg, Virginia 24061, United States.
authors.forename: Gregory B
authors.initials: GB
authors.lastname: Fahs
authors.affiliation: Department of Chemistry, Macromolecules and Interfaces Institute, and ‡Department of Physics, Virginia Tech , Blacksburg, Virginia 24061, United States.
authors.forename: David L
authors.initials: DL
authors.lastname: Inglefield
authors.affiliation: Department of Chemistry, Macromolecules and Interfaces Institute, and ‡Department of Physics, Virginia Tech , Blacksburg, Virginia 24061, United States.
authors.forename: Chainika
authors.initials: C
authors.lastname: Jangu
authors.affiliation: Department of Chemistry, Macromolecules and Interfaces Institute, and ‡Department of Physics, Virginia Tech , Blacksburg, Virginia 24061, United States.
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Macromolecules and Interfaces Institute, and ‡Department of Physics, Virginia Tech , Blacksburg, Virginia 24061, United States.
authors.forename: James R
authors.initials: JR
authors.lastname: Heflin
authors.affiliation: Department of Chemistry, Macromolecules and Interfaces Institute, and ‡Department of Physics, Virginia Tech , Blacksburg, Virginia 24061, United States.
authors.forename: Robert B
authors.initials: RB
authors.lastname: Moore
authors.affiliation: Department of Chemistry, Macromolecules and Interfaces Institute, and ‡Department of Physics, Virginia Tech , Blacksburg, Virginia 24061, United States.
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Long
keywords: block copolymers; controlled polymerization; electromechanical actuators; ionic liquids; self-assembly