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