Imidazolium-Containing ABA Triblock Copolymers as Electroactive Devices

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• 作者：Evan Margaretta ; Gregory B. Fahs ; David L. Inglefield Jr. ; Chainika Jangu ; Dong Wang ; James R. Heflin ; Robert B. Moore ; Timothy E. Long
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：January 20, 2016
• 年：2016
• 卷：8
• 期：2
• 页码：1280-1288
• 全文大小：528K
• ISSN：1944-8252

文摘

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 <sup>1sup>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<sup>–4sup> 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.