Enhancement of polypyrrole linear actuation with poly(ethylene oxide)

•Polyethylene oxides in electropolymerization forming more compact PPy films.•Linear actuators of PPy-PEO/DBS showing significant increase in strain.•The ion diffusion coefficient and strain rate is improved in PPy-PEO/DBS.

In the present paper, we report the electro-chemo-mechanical deformation (ECMD) measurements of pristine polypyrrole (PPy) and polypyrrole/poly(ethylene oxide) composite films doped with dodecylbenzenesulfonate (DBS) under isotonic (constant force) conditions. The PPy/DBS and PPy-PEO/DBS films, the latter made from a polymerization solution containing 5 wt% PEO, were actuated potentiodynamically in an aqueous solution containing lithium bis-trifluoromethane-sulfonimide (LiTFSI). The obtained composite films were characterized with scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy and Fourier transform infrared spectroscopy (FTIR). The results confirmed the successful incorporation of PEO within the PPy film. The composite films showed a remarkable improvement in maximum strain achieved (of 7.7%), nearly double that of the pristine PPy/DBS film, had a higher conductivity, higher ion diffusion coefficient and faster strain rate. The ECMD measurements for both the pristine as well as the PEO-composite films showed cation driven actuation involving the migration of Li+ cations in the aqueous electrolyte.