The immobilization of dodecylbenzenesulfonate (DBS−) in polypyrrole (PPy) during electropolymerization is typically expected to lead to cation-driven activity. Here we demonstrate that the actuation direction changed by using same electrolyte but different solvent.

Either as salts or room temperature ionic liquids, fluorinated anion-based electrolytes have been a common choice for ionic electroactive polymer actuators, both linear and bending. In the present work, propylene carbonate solutions of four electrolytes of the three hugely popular anions—triflouromethanesulfonate, bis(trifluoromethane)sulfonimide, and hexafluorophosphate were compared and evaluated in polypyrrole linear actuators. The actuation direction, the characteristics—performance relations influence the behavior of the actuators. Isotonic Electro-chemo-mechanical deformation (ECMD) measurements were performed to study the response of the PPy/DBS samples. The highest strain for pristine PPy/DBS linear actuators was found in range of 21% for LiTFSI, while TBAPF6 had the least cation involvement, suggesting the potential for application in durable and controllable actuators. Interesting cation effects on the actuation of the same anions (CF3SO3−) were also observed.

While carbide-derived carbon (CDC)-based materials have shown stable behavior in ionic electro-chemomechanical actuators, the displacement and actuation speed have remained low compared to conducting polymer-based actuators. The goal of this research was to obtain more responsive conducting polymer-CDC composite films and to investigate their linear actuation properties, comparing the stress and strain to those of polypyrrole (PPy) doped with dodecylbenzenesulfonate (DBS À ). The PPy-CDC hybrid films were synthesized electrochemically using polyoxometalate (POM) (phosphotungstic acid) to attach charge to the CDC particles for embedding them into the PPy matrix as secondary dopants in addition to DBS À . Cyclic voltammetry and square wave potential steps in electro-chemo-mechanical deformation (ECMD) measurements were performed in aqueous electrolyte solution, showing that the PPy-CDC hybrids had higher strain (12%) and stress (0.6 MPa) than the PPy/DBS films. The new composite was investigated by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy to evaluate the composition of these promising materials.

Conducting polymers such as polypyrrole (PPy) can be deposited on various substrates to obtain conductive electroactive coatings. While electrochemical coatings are generally considered to be more effective, chemical coatings are more industrially suitable, especially on complex substrates. In this work, we aimed to explore the electro‐chemo‐mechanical response of conductive fiber scaffolds (CFS) prepared by coating PPy (chemically) on glucose‐gelatin nanofibre scaffolds. Electroactivity was readily observed in both aqueous and propylene carbonate solutions of lithium bis(trifluoromethanesulfonyl)imide, with mainly anion activity in both cases. A higher actuation response was achieved in the aqueous solutions with strain in the range of 1.2% and stress in the range of 3 kPa. Under both cyclic voltammetry and square wave potential steps driving, stable actuation for over 100 cycles was maintained. In addition to actuation, the CFS samples exhibited concurrent sensory properties, in sensing current densities and mechanical load. The PPy‐coated CFS material functioning as both an actuator and a sensor is envisaged to have potential applications in smart materials, soft robotics or e‐skin. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48533.

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In films of conducting polymers, the electrochemical reaction(s) drive the simultaneous variation of different material properties (reaction multifunctionality). Here, we present a parallel study of actuation-sensing-energy storage triple functionality of polypyrrole (PPy) blends with dodecylbenzenesulfonate (DBS-), PPy/DBS, without and with inclusion of polyethyleneoxide, PPy-PEO/DBS. The characterization of the response of both materials in aqueous solutions of four different salts indicated that all of the actuating, sensing and charge storage responses were, independent of the electrolyte, present for both materials, but stronger for the PPy-PEO/DBS films: 1.4× higher strains, 1.3× higher specific charge densities, 2.5× higher specific capacitances and increased ion-sensitivity towards the studied counterions. For both materials, the reaction energy, the material potential and the strain variations adapt to and sense the electrical and chemical (exchanged cation) conditions. The driving and the response of actuation, sensing and charge can be controlled/read, simultaneously, via just two connecting wires. Only the cooperative actuation of chemical macromolecular motors from functional cells has such chemical multifunctionality.

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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.