Optimization of peak current of poly(3,4-ethylenedioxythiophene)/multi-walled carbon nanotube using response surface methodology/central composite design

Modification of electrode surface with poly(3,4-ethylenedioxythiophene)/multi-walled carbon nanotube (PEDOT/MWCNT) composite prepared by electrodeposition technique was reported in this study. The optimization of peak current response of PEDOT/MWCNT was performed by utilizing the combination of response surface methodology and central composite design (RSM/CCD). The effect of each variable and the interaction between three variables i.e. the concentration of MWCNT, electrodeposition potential and deposition time were studied and modeled. The statistical analysis showed that the concentration of MWCNT and deposition time have significantly affected the peak current response. A reduced cubic model equation with the coefficient of determination (R-2) value of 0.9973 was developed. The optimized condition predicted by the software was compared with the experiment and resulting in less than 2% error, indicating that this model was reliable and able to predict the peak current response accurately. Additionally, the electrochemical properties, chemical properties and morphology of the optimized modified electrode were characterized by cyclic voltammetry (CV), Fourier transform infrared (FTIR), Raman spectroscopy and field emission scanning electron microscopy (FESEM). The peak current of the optimized PEDOT/MWCNT modified electrode was higher than electrode without MWCNT and the FESEM study demonstrated that the tubular structure of MWCNT was uniformly wrapped by PEDOT. The FTIR and Raman spectra proved that MWCNT was successfully incorporated into PEDOT.