Interpenetrated triple polymeric layer as electrochemomechanical actuator: Solvent influence and diffusion coefficient of counterions

Full polymeric trilayers formed by two lateral polypyrrole-dodecylbenzoesulfate (PPyDBS) films interpenetrating a polyvinylidene fluoride (PVdF) central membrane were electrochemically characterized. Square wave voltammetric and square wave amperometric responses in 0.5 M LiCIO4 solutions using different solvents was undertaken with parallel video-recording of the reversible angular displacements. According to the bending Movemetits in aqueous and ethylene glycol (EG) Solutions the PPyDBS films shrunk upon oxidation and swelled during reduction: the electrochemical reactions drive the exchange of cations in both solvents. In propylene carbonate (PC) and acetonitrile (AN) solutions the PPyDBS films swelled and shrunk by oxidation and reduction, respectively, driven by the exchange of anions. Propylene carbonate and acetonitrile hinder the dissociation of the LiDBS ionic couples inside the PPyDBS film forcing the exchange of anions to compensate polarotis on polypyrrole. The diffusion coefficient of the exchanged ions and the angular rates follow the sequence: aqueous > PC >AN > EG solutions. Whatever the solvent, actuators are Faradaic devices: the described angle is a linear function of the consumed charge. (C) 2017 Elsevier Ltd. All rights reserved

Polypyrrole coatings on gelatin fiber scaffolds: Material and electrochemical characterizations in organic and aqueous electrolyte

Polypyrrole (PPy) was chemically deposited on glycose-crosslinked gelatin fiber scaffold (FS) by simple dip coating technique, resulting in conductive fiber scaffolds (CFS). The CFS samples were comparatively studied in aqueous and propylene carbonate solutions of equal concentrations of lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) electrolyte. Our aim in this work was to characterize the mechanical and electrochemical properties of the CFS samples. The new CFS material was characterized by scanning electron microscopy (SEM) and FTIR measurements confirming chemical oxidized PPy deposits on FS. The electrochemical measurements applying cyclic voltammetric, chronoamperometric and chronopotentiometric measurements showed that while diffusion coefficients for both solvents were in similar range, the exchanged charge was nearly doubled in aqueous solutions. The specific capacitance of the CFS had the highest value in aqueous electrolyte reaching 175 F g(-1), which suggests that in addition to smart tissue engineering, this novel CFS material could also find application in energy storage

Role of polymerization temperature on the performance of polypyrrole/dodecylbenzenesulphonate linear actuators

Polypyrrole doped with dodecylbenzenesulphonate (PPy/DBS) free-standing films were electropolymerized in sodium perchlorate propylene carbonate solution at different temperatures, observing increasing conductivity with decreasing synthesis temperature. Our goal in this study was to evaluate how the linear actuation of PPy depends on the polymerization temperature. The anion driven actuation of materials synthesized at lower temperatures changed to mainly cation active for PPy/DBS films polymerized at 20 degrees C; the latter films also showed the highest diffusion coefficients. Scanning electron microscopy did show that the surface roughness of the films increased with increasing synthesis temperature, as expected. Isometric and isotonic electro-chemo mechanical deformation (ECMD) measurements were performed with combined electrochemical techniques (cyclic voltammetry and chronoamperometry), revealing wide differences in the actuation behavior

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