Preparation and capacitive performances of PEDOT/indigo carmine composite hydrogel

In this article, indigo carmine (IC) was introduced into poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT‐PSS) hydrogel by in situ polymerization to prepare PEDOT/IC composite hydrogel. The structural characterization of PEDOT/IC composite hydrogel was analyzed by Fourier‐transform infrared spectroscopy (FTIR), UV–vis spectroscopy, X‐Ray diffraction (XRD), and Scanning electron microscopy (SEM). The results indicated that IC was successfully introduced into PEDOT‐PSS hydrogel. Electrochemical performances were investigated by cyclic voltammetry, galvostatic charge‐discharge, and electrochemical impedance technology. The specific capacitance of PEDOT‐PSS hydrogel was efficiently increased by the introduction of IC. The specific capacitance of PEDOT‐PSS hydrogel increased first and then decreased with the increase of the concentration of IC. The specific capacitance of PEDOT‐PSS hydrogel was increased from 38F/g to a maximum value of 123F/g (current density = 0.5 A/g) when the concentration of IC reached 5 mM. On the basis of cycle‐life tests, the capacitance retention of about 68% for the PEDOT/IC composite hydrogel after 5000 cycles suggested a high cycle stability of PEDOT/IC composite hydrogel and its potential as an electrode material for supercapacitor applications. POLYM. COMPOS., 34:989–996, 2013. © 2013 Society of Plastics Engineers