Role of polyethylene oxide content in polypyrrole linear actuators

In this study, polypyrrole (PPy)-PEO composite films, doped with dodecylbenzene sulfonate, were electropolymerized from solutions with different concentrations of PEO. The obtained films were studied by atomic force microscopy (AFM), scanning electron microscopy (SEM), Raman, FTIR and energy dispersive X-ray spectroscopy (EDX). Electrochemical impedance spectroscopy (EIS) and modified scanning ionic conductance microscopy (mSICM) allowed the determination of electronic and ionic conductivities of the samples. Their electro-chemo-mechanical deformations (ECMD) were investigated under cyclic voltammetry. In aqueous electrolyte, the samples showed expansion/contraction during reduction/oxidation, respectively (cation-driven), while opposite behaviour - expansion/contraction during oxidation/reduction (anion-driven) behaviour was observed in propylene carbonate solutions. These films obtained from solutions with a PEO content of 5% showed the highest deformations (strain and stress). They also presented the highest ionic and electronic conductivities and redox charge density. The ECMD deformation per unit of redox charge was much higher in PC solutions than in aqueous solutions: more PC molecules are exchanged for osmotic balance per unit of redox charge.
Source: Materials Today Communications - Category: Materials Science Source Type: research