Ion-selectivity of polypyrrole carbide-derived carbon films in aqueous electrolytes

In this work, we have combined polypyrrole (PPy) doped with dodecylbenzene sulfonate (DBS-) and carbide-derived carbon (CDC), forming PPyCDC (PPy/DBS-CDC) composites. Scanning electron microscopy revealed for PPyCDC that most CDC particles are located on the surface of the films. This work's main goal is to investigate the ion-selectivity of the novel PPyCDC composite by linear actuation studies, with primary actuation taking place at discharging. Four different aqueous electrolytes are applied with hydrophobic cations, such as TMA(+) (tetramethylammonium ion) and EDMI+ (1-ethyl-2,3-dimethyl imidazolium ion). They are hydrophilic with Li+ (lithium-ion) and Na+ (sodium ion). It was possible to distinguish each cation from linear actuation studies, either cyclic voltammetry or square wave potential steps. In the case of pristine PPy/DBS, that ion differentiation could not separate. Chronopotentiometric measurements of both films (PPyCDC and PPy/DBS) were performed. It could control (read) the strain for PPyCDC films and the potential at constant current density. The electrical energy adapts to exchange cations, forming a sensor device with ion-selectivity of the applied cations considering their hydrophilic and hydrophobic characteristics. The best specific capacitance (energy storage) is found for EDMI+ cations in PPyCDC films with 193 F g(-1), enabling this composite in multifunctional applications.