Debye Length Dependence of the Anomalous Dynamics of Ionic Double Layers in a Parallel Plate Capacitor

Abstract

The electrical impedance spectrum of simple ionic solutions is measured in a parallel plate capacitor at small applied ac voltage. The influence of the ionic strength is investigated using several electrolytes at different concentrations in solvents of different dielectric constants. The electric double layers that appear at the electrodes at low frequencies are not perfectly capacitive. At moderate ionic strength, ion transport agrees with a model based on the Poisson–Nernst–Planck (PNP) equations. At low ionic strength, double layer dynamics deviate from the PNP model, and the deviation is well described by an empirical function with only one fit parameter. This deviation from the PNP equations increases systematically with increasing Debye length, possibly caused by the long-range Coulomb interaction.

Electrode covering effect on the electric response of a cell to external stimulus

“…1. The deviation of the slope of log X versus log X from À1 has been observed by many authors [29,30]. A possible interpretation of the experimental data reported in [29,30] could be the presence of non-homogeneities on the electrodes, as considered in our paper.…”

“…The deviation of the slope of log X versus log X from À1 has been observed by many authors [29,30]. A possible interpretation of the experimental data reported in [29,30] could be the presence of non-homogeneities on the electrodes, as considered in our paper. These effects have been described using anomalous diffusion invoking the non-validity of the Fick law near the electrodes [31,32].…”

Fabrication and Characterization of Nanoporous Gold Electrodes for Sensor Applications

“…In such cases, the dynamics of ions in solution at the electric double layer can break from the standard solution to the Poisson‐Nernst‐Planck equations (anomalous diffusion). As a result, fractional exponents arise in the resulting solution to the Poisson‐Nernst‐Planck equations and this solution can be effectively described by general CPE model rather than the Warburg special case. In the experiments conducted (see Table ), values of α above 0.9 were obtained for both the NPAu/water and NPAu/DCE interfaces.…”

Thermodynamic Charge-to-Mass Sensor for Colloids, Proteins, and Polyelectrolytes

“…Samples were continuously stirred at 700 min −1 with a magnetic stirrer. Impedance spectra were fitted following ref 30 in terms of a constant-phase element in series with a resistor of magnitude R that is in parallel with a capacitor of magnitude C ω ω ω ω…”