Search Results (2)

Researchers have focused on incorporating porous carbon particles such as carbon-derived carbon (CDC) into polypyrrole (PPy), preferably on the surface, to achieve high-capacitive electrodes. Less attention is afforded to their linear actuation properties. Therefore, in this work, we chose two different electropolymerization processes using the typical PPy doped with dodecylbenzene sulfonate (DBS⁻) and added CDC particles, compared with CDC with phosphotungstic acid (PTA), forming CDC-PT⁴⁻ dopants. The resulting PPy/DBS-CDC (PPyCDC) and PPy/DBS-CDC-PT (PPyCDC-PT) films showed different morphologies, with PPyCDC having the most CDC particles on the surface with less surrounding PPy, while in PPyCDC-PT, all the CDC particles were covered with PPy. Their linear actuation properties, applying electrochemical techniques (cyclic voltammetry and square wave potential steps), were found to enhance the PPyCDC-PT films in organic (2-times-higher strain) and aqueous electrolytes (2.8-times-higher strain) in an applied potential range of 0.8 V to −0.5 V. The energy storage capability found for the PPyCDC was favorable, with 159 ± 13 F cm⁻³ (1.2 times lower for PPyCDC-PT) in the organic electrolyte, while in the aqueous electrolyte, a result of 135 ± 11 F cm⁻³ was determined (1.8 times lower for PPyCDC-PT). The results showed that PPyCDC was more favorable in terms of energy storage, while PPyCDC-PT was suitable for linear actuator applications. The characterization of both the film samples included scanning electron microscopy (SEM), Raman, FTIR, and energy-dispersive X-ray (EDX) spectroscopy. Full article

Linear actuators based on polypyrrole (PPy) are envisaged to have only one ion that triggers the actuation direction, either at oxidation (anion-driven) or at reduction (cation-driven). PPy doped with dodecylbenzenesulfonate (PPy/DBS) is the most common applied conducting polymer having cation-driven actuation in aqueous solvent and mainly anion-driven actuation in an organic electrolyte. It is somehow desired to have an actuator that is independent of the applied solvent in the same actuation direction. In this research we made PPy/DBS with the addition of phosphorus tungsten acid, forming PPyPT films, as well with included carbide derived carbon (CDC) resulting in PPyCDC films. The solvent in electropolymerization was changed from an aqueous ethylene glycol mixture to pure EG forming PPyPT-EG and PPyCDC-EG composites. Our goal in this study was to investigate the linear actuation properties of PPy composites applying sodium perchlorate in aqueous (NaClO₄-aq) and propylene carbonate (NaClO₄-PC) electrolytes. Cyclic voltammetry and square potential steps in combination with electro-chemo-mechanical-deformation (ECMD) measurements of PPy composite films were performed. The PPyPT and PPyCDC had mixed ion-actuation in NaClO₄-PC while in NaClO4-aq expansion at reduction (cation-driven) was observed. Those novel PPy composites electropolymerized in EG solvent showed independently which solvent applied mainly expansion at reduction (cation-driven actuator). Chronopotentiometric measurements were performed on all composites, revealing excellent specific capacitance up to 190 F g⁻¹ for PPyCDC-EG (best capacitance retention of 90 % after 1000 cycles) and 130 F g⁻¹ for PPyPT-EG in aqueous electrolyte. The films were characterized by scanning electron microscopy (SEM), Raman, Fourier-transform infrared (FTIR) and energy dispersive X-ray spectroscopy (EDX). Full article