Reaction/diffusion at conducting polymer ultramicroelectrodes†

Approximate Analytical Solution of Nonlinear Reaction’s Diffusion Equation at Conducting Polymer Ultramicroelectrodes

“…Figure 4 indicates the normalized steady-state current ψ for all values of α. From Figure 4(a), it is noticed that our analytical results (9) and (11) agree with the limiting result of Lyons et al [24] work. The normalized steady-state current for all large values of α is calculated using (9) in Figure 4(b).…”

“…In the case when the substrate diffusion in the adjacent solution is neglected, the expression corresponding to the concentration of substrate (5) and current (6) was provided by Lyons et al [24] (refer to Table 1). Figure 2 represents the substrate concentration u for various values of the reaction diffusion parameter γ and for α ≤ 1.…”

“…On the other hand, the reaction/diffusion equation under steady-state condition corresponding to the normalized substrate concentration within the polymer film can be expressed as [24] Normalized distance ρ Normalized substrate concentration Figure 3: Plot of normalized substrate concentration "u" at a microelectrode modified with a polymer film as a function of "ρ". The concentrations were computed using (8) for various values of the reaction diffusion parameter "γ" when (a) α = 10 for c Σ denotes the total catalyst concentration in the film, and D S is the diffusion coefficient of the substrate within the polymer film.…”

“…In this case transport and kinetics are described by (1), but the boundary conditions are given by [24] du where the Biot number v has been introduced…”

“…Further, the analytical applications of various polymermodified sensors and the reaction/diffusion at the conducting polymer electrode (where the chemical reaction term is described by Michaelis-Menten kinetics) were reviewed extensively by various groups [19][20][21][22][23]. Recently, Lyons et al [24] evaluated the analytical solutions corresponding to the steady-state substrate concentration profile and current observed at a conducting polymer microelectrode when the substrate concentration is low. For higher values of the substrate concentration, a kinetic rate law based on the Michaelis-Menten equation is more appropriate.…”