Enhancement of polypyrrole linear actuation with poly(ethylene oxide) (original) (raw)
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International Journal of Nanotechnology
We show improvement in linear actuation properties of polypyrrole-doped dodecylbenzenesulfonate (PPy/DBS) by incorporating varying amounts of polyethylene oxide (5 wt % or 15 wt %) into PPy during electroploymerisation (PPy/DBS-PEO). Knowing that pristine PPy/DBS linear actuators in aqueous electrolytes are driven by cation ingress during reduction, the actuation properties are studied in isotonic (length change) mode of electro-chemo-mechanical-deformation (ECMD) measurements. Scanning electronic microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy revealed that PEO is incorporated in PPy/DBS films. ECMD studies revealed a threefold improvement in electronic conductivity for the PPyDBS-PEO 15% film that also demonstrated improved strain of 7% in comparison to the strain of PPy/DBS film of 1.9%.
Influence of solvent on linear polypyrrole-polyethylene oxide actuators
Journal of Applied Polymer Science, 2018
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 electrochemo-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.
2011
The low-voltage electromechanical actuation of polypyrrole (PPy) doped with di-(2-ethylhexyl) sulfosuccinate (DEHS) has been investigated. The PPy-DEHS has been prepared both chemically (cast as films from solution) and by more conventional electrochemical polymerization. Very large strains of ∼30% were obtained during slow-scan redox cycling of the electrochemically prepared PPy-DEHS films. In constrast, PPy-DEHS films cast from solutions of the chemically polymerized polymer gave actuation strains of ∼2.5%. The polymerization method was also found to have a significant effect on the structure, conductivity and mechanical properties of the PPy-DEHS materials. The conductivity of the electrochemically polymerized PPy-DEHS was 75 S cm −1 , considerably higher than that found for the chemically derived polymer (7 S cm −1). The structure of the PPy-DEHS was further elucidated from UV-vis, Raman and FT-IR spectral studies which indicated that the conjugation length of the PPy could be increased significantly by varying the polymerization method. Films obtained by casting chemically prepared PPy-DEHS showed higher modulus (2.3 GPa) than electropolymerized PPy-DEHS (0.6 GPa), but were more brittle. Both materials were electroactive in acetonitrile/water electrolyte. The higher actuation strain observed in the electrochemically prepared films was attributed to a more open molecular structure (as indicated by the lower modulus) allowing for easier ion diffusion and a higher conductivity allowing easier charge transfer.
Materials, 2022
Controllable linear actuation of polypyrrole (PPy) is the envisaged goal where only one ion dominates direction (here anions) in reversible redox cycles. PPy with polyethylene oxide (PEO) doped with dodecylbenzenesulfonate forms PPy-PEO/DBS films (PPy-PEO), which are applied in propylene carbonate (PC) solvent with electrolytes such as 1-ethyl-2,3-dimethylimidazolium trifluoromethanesulfonate (EDMICF3SO3), sodium perchlorate (NaClO4) and tetrabutylammonium hexafluorophosphate (TBAPF6) and compared in their linear actuation properties with pristine PPy/DBS samples. PPy-PEO showed for all applied electrolytes that only expansion at oxidation appeared in cyclic voltammetric studies, while pristine PPy/DBS had mixed-ion actuation in all electrolytes. The electrolyte TBAPF6-PC revealed for PPy-PEO best results with 18% strain (PPy/DBS had 8.5% strain), 2 times better strain rates, 1.8 times higher electronic conductivity, 1.4 times higher charge densities and 1.5 times higher diffusion c...
Role of polyethylene oxide content in polypyrrole linear actuators
Materials Today Communications, 2020
Current research on conducting polymer composite actuators has been mainly focused on achieving increased linear actuation with improved electrical, physical and chemical properties. Polyethylene oxide (PEO) has been shown to enhance both mechanical and electrical properties of conducting polymers at certain concentrations. However, as some of these effects peak off, the optimal concentration is difficult to determine. 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 behaviourexpansion/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.
Electrochemistry of interlayer supported polypyrrole tri-layer linear actuators
Electrochimica Acta, 2014
Electro-chemo-mechanical deformation of polypyrrole doped with dodecylbenzenesulfonate (PPy/DBS), deposited electrochemically on chitosan and polyvinylidene fluoride (PVdF) substrates made conductive by chemically deposited poly(3,4-ethylenedioxythiophene) (PEDOT) are examined. The electronic conductivity and structural properties (by Raman and FTIR spectroscopy) of the chemically deposited PEDOT on chitosan film and PVdF membrane are characterized. The linear actuation response of PPy/DBS films on the two substrates in tetrabutylammonium trifluoromethanesulfonate in propylene carbonate electrolyte is investigated under isotonic (constant force) conditions. The goal of this study was to obtain novel linear actuators with mechanically stable tri-layer design and controllable strain, and to compare the effect of two completely different substrate materials on the properties of the conducting polymer coatings.
Investigation of bi-ionic contribution for the enhancement of bending actuation in polypyrrole film
Sensors and Actuators B-chemical, 2003
Electrochemomechanical deformation (ECMD) in the electrodeposited polypyrrole (PPy) ®lms was examined by judicious selection of the supporting electrolytes during electropolymerization and cyclic voltammetry (CV). A critical perusal of the ECMD characteristics corroborates the cation-driven and/or anion-driven deformation in the PPy ®lms. It was found that a freestanding PPy ®lm successively electrodeposited as a cation-driven layer followed by an anion-driven layer works as a bimorph actuator. The large bending motions were observed in 1 M NaCl solution in which both anion-driven and cation-driven layers are electroactive. In contrast, the bending motions were found to be suppressed in both 1 M ethylbenzene sulfonic acid sodium salt and 1 M tetrabutylammonium chloride, in which only one of the cation-driven or the anion-driven layer is electroactive. The results indicate that the bimorph actuator driven by the synchronized insertion and deinsertion of anion and cation, which can be expressed as the bi-ionic actuator, clearly enhances its bending motion compared to that observed in the conventional bimorph actuators driven by mono-ionic ECMD behaviors. #
Polypyrrole linear actuation tuned by phosphotungstic acid
Sensors and Actuators B: Chemical
Co-doping polypyrrole (PPy) with dodecylbenzenesulfonate and multicharged phosphotungstate anions (PT) from the phosphotungstic acid (PTA) led to free-standing PPy/DBS-PT films, which were studied for their linear actuation properties. FTIR and Raman spectra revealed that PT was successfully embedded in PPy/DBS during electropolymerisation. Isometric stress and isotonic strain measurements in aqueous electrolyte under various electrochemical experiments showed an increase in the obtainable strain and stress, which was attributed to the electrocatalytic role PTA plays during the electropolymerisation. This results in lower synthesis potential and the formation of more compact films in comparison to PPy/DBS films under equal conditions. With the improved structure as well as the higher-charged immobilized PT dopant, 17 times higher conductivities, 1.7 times higher redox charge, and 1.8 times higher specific capacitance were obtained (at equal frequency). Energy dispersive X-ray (EDX) spectra indicated that contrary to some other published works, the majority of PT stayed stably in the film during consecutive redox cycles.
Synthetic Metals, 2019
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°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.