Influence of solvent on linear polypyrrole-polyethylene oxide actuators

Ionic conductivity of polypyrrole (PPy) doped with dodecylbenzenesulfonate (DBS) was improved by loading of 10 wt % of polyethylene oxide (PEO). The linear actuation properties of PPy-PEO/DBS films were investigated and compared in polar (aqueous) and aprotic (propylene carbonate) solvents keeping the concentration of lithium bis(trifluoromethane)sulfonimide (LiTFSI) electrolyte the same. The results were compared to those of pristine PPy/DBS films. The actuation direction changed from pure cation-driven in the aqueous electrolyte (LiTFSI(aq)) to anion-driven in propylene carbonate electrolyte (LiTFSI(PC)). At the same time, the electro-chemo-mechanical deformation revealed that the strain of PPy-PEO/DBS increased from 5% in LiTFSI(aq) to 20% in LiTFSI(PC). The effect of solvent on the ionic conductivity was investigated using electrochemical impedance spectroscopy, showing a 27% increase in charge transfer kinetics and an increase in the electronic conductivity, resulting in significant increase in the strain rate, when propylene carbonate electrolyte was used. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46831