**3.1.2.3 Effect of temperature and calculation of thermodynamic parameters**

The potentiodynamic polarization curves as a function of the solution temperature in the range between 293 and 313 K under the optimum experimental conditions as mentioned above (i.e. 0.04M monomer and 0.6M acid in case of OCP or 0.08M monomer and 0.6M acid in case of OHP) were illustrated in Figure 9(a and b). From the figure, it is clear that, an increase of the reaction temperature resulted in a progressive increase of the charge included in the anodic peaks. The plot of the log (i*p1)* versus 1/T is represented in Figure 9 (c and d), straight lines are obtained with slopes equal to -1.44 in case of OCP and -1.17 in case of OHP. The apparent activation energies were calculated using Arrhenius equation [sayyah et al, 2010] and it is found to be 27.57kJ mol-1 for OCP and 22.39 kJ mol-1 for OHP. The enthalpy ΔH\* and entropy ΔS\* of activation for the electropolymerization reaction can be calculated from Eyring equation plot at different temperatures (Fig. 9(e and f)) we obtained linear relationships with slopes of -ΔH\*/2.303R and intercepts of log {(R/Nh) +

Fig. 8. Cyclic voltammetry curves showing the effect of acid concentration on

**3.1.2.3 Effect of temperature and calculation of thermodynamic parameters** 

The potentiodynamic polarization curves as a function of the solution temperature in the range between 293 and 313 K under the optimum experimental conditions as mentioned above (i.e. 0.04M monomer and 0.6M acid in case of OCP or 0.08M monomer and 0.6M acid in case of OHP) were illustrated in Figure 9(a and b). From the figure, it is clear that, an increase of the reaction temperature resulted in a progressive increase of the charge included in the anodic peaks. The plot of the log (i*p1)* versus 1/T is represented in Figure 9 (c and d), straight lines are obtained with slopes equal to -1.44 in case of OCP and -1.17 in case of OHP. The apparent activation energies were calculated using Arrhenius equation [sayyah et al, 2010] and it is found to be 27.57kJ mol-1 for OCP and 22.39 kJ mol-1 for OHP. The enthalpy ΔH\* and entropy ΔS\* of activation for the electropolymerization reaction can be calculated from Eyring equation plot at different temperatures (Fig. 9(e and f)) we obtained linear relationships with slopes of -ΔH\*/2.303R and intercepts of log {(R/Nh) +

electropolymerization and its related double logarithmic plot.

ΔS\*/2.303R}. From slopes and intercepts the values of ΔH\* and ΔS\* were found to be 31.54 k J mol-1 and -99.68 JK-1 mol -1, respectively for OCP and 19.87k J mol-1 and –286.69 JK-1 mol -1, respectively for OHP.

Fig. 9. Cyclic voltammetry curves for the effect of temperature on the electropolymerization, Arrhenius plot and Eyring equation plot
