Capacitance properties and structure of electroconducting hydrogels based on copoly(aniline – p-phenylenediamine) and polyacrylamide

• Electroactive hydrogels based on PAAM and polyaniline copolymers were prepared.
• Optimal composition for highest properties was found.
• Hydrogels display a high specific capacitance in wide range of current densities.
• After 1000 cycles the hydrogels keep more than 100% of their initial capacitance.

Electroconducting hydrogels (EH) based on copoly(aniline – p-phenylenediamine) grafted to the polyacrylamide for the application as pseudo-supercapacitor's electrodes have been prepared. The influence of preparation conditions on the structure and capacitance properties of the systems were investigated: we determined the optimal amount of p-phenylenediamine to obtain the network of swollen interconnected nanofibrils inside the hydrogel which provides the formation of continuous conducting phase. Structure and morphology of the prepared samples were investigated with UV–VIS spectroscopy, scanning electron microscopy (SEM) and wide-angle X-ray diffraction (WAXD). The maximal value of capacitance was 364 F g−1 at 0.2 A g−1. It was shown that the EH samples demonstrate the retention of 50% of their capacity at high current density 16 A g−1. Cycle-life measurements show evidence that capacitance of EH electrodes after 1000 cycles is higher than its initial value for all prepared samples. Changes of the copolymer structure during swelling in water have been studied with WAXD.

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