Studies on electrochemical activity of CNT/PANI composite thin film coating on ITO coated glass surfaces: Effect of concentration on fractal dimension

- CNT/PANI films have been electrodeposited on ITO substrates by changing concentration of the acid solution.
- Effect of fractal dimension on the interfacial properties between film and electrolyte has been studied using dual approach by cyclic voltammetry and electrochemical spectroscopy.
- Double log plot from cyclic voltammetry is used to find fractal dimension.
- Log-log plot of frequency vs. impedance provides information about fractal dimension and CPA behaviour.
- Results have been used to interpret and correlate the evolution of fractal dimension with change in concentration.

Thin films of CNT/PANI composites have been deposited potentiostatically by electrochemical polymerization from a solution of CNT dispersed in aniline monomer and H2SO4 on ITO coated glass substrates. H2SO4 concentration in aniline monomer solution has been varied and its effect on electrochemical properties of films has been studied. To elucidate information about the degree of surface disorder, surface growth mechanism and the kinetics of electrochemical reactions at the surfaces, fractal dimensions has been evaluated using two electrochemical techniques: cyclic voltammetry and electrochemical impedance spectroscopy. It is observed that as acid concentration in the deposition solution increases, fractal dimension of the deposited film varies from DF = 1 corresponding to a series of isolated islands, increasing to 2 for a planar 2D configuration for smooth surfaces and finally reaching a value of 2< DF <3 for rough and porous surface of the electrodes. Results obtained from both the techniques are found to be in good agreement with the fractal dimension values lying between those for smooth and porous/rough surface.

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