Some aspects of impedance measurements at the interface between two immiscible electrolyte solutions in the four-electrode cell

Trojánek, Antonı́n; Mareček, Vladimı́r; Samec, Zdeněk

doi:10.1016/j.electacta.2014.12.013

Cited by 12 publications

(14 citation statements)

References 25 publications

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“…7,8,53 They proposed that the measured discrepancy between tension and impedance spectroscopy that results at larger potentials is an artifact arising from the inadequate representation of the interface and/or the electrochemical cell by the Randles equivalent circuit. Our results demonstrate that the PB-PMF model provides an excellent description of both nanoscale and macroscale characterizations of the interface by X-ray reflectivity and interfacial tension measurements.…”

Section: Discussionmentioning

confidence: 99%

“…As stated in Ref. 53, the high frequency semicircle is a result of the stray capacitance and resistance associated with the parasitic coupling of the reference and counter electrodes, as well as the resistance of the bulk solution. None of these effects are the direct consequence of the double layer capacitance that is of interest in this study.…”

Section: 32mentioning

confidence: 99%

“…We had limited success fitting the high frequency part of our data, and could only fit the mid-frequency range (40-3000 Hz) of these data, most likely because of the larger size and different geometry of our sample cell compared to that used in Ref. 53. As stated in Ref.…”

Section: 32mentioning

confidence: 99%

“…7,8,[18][19][20]53 As with the Randles equivalent circuit that we have used, these equivalent circuits often provide an acceptable fit of impedance spectroscopy data. First, we note that the simplest equivalent circuit, consisting of a capacitor and resistor in series (Fig.…”

Section: 32mentioning

confidence: 99%

“…An example of a more complicated equivalent circuit has been demonstrated in Ref. 53 for the purposes of fitting the high frequency semi-circular (or semi-elliptical in our case) part of the real and imaginary parts of the impedance, as well as accounting for parasitic couplings of the reference and counter electrodes. We had limited success fitting the high frequency part of our data, and could only fit the mid-frequency range (40-3000 Hz) of these data, most likely because of the larger size and different geometry of our sample cell compared to that used in Ref.…”

Section: 32mentioning

confidence: 99%

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Ion Distributions at Electrified Water-Organic Interfaces: PB-PMF Calculations and Impedance Spectroscopy Measurements

Hou

Luo

et al. 2015

J. Electrochem. Soc.

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The interface between two immiscible electrolyte solutions consisting of alkali chlorides in water and the organic electrolyte BTPPATPFB in 1,2-dichloroethane is characterized with X-ray reflectivity, interfacial tension and impedance spectroscopy measurements over a range of applied voltage between the bulk solutions. X-ray reflectivity probes the interfacial ion distribution on the sub-nanometer length scale, whereas interfacial tension and impedance spectroscopy characterize quantities such as interfacial excess charge and differential capacitance that represent integrations over the interfacial ion distribution. Predictions of interfacial ion distributions by the recently introduced PB-PMF method, which combines Poisson's equation with ion potentials of mean force, provide excellent agreement, within one to two experimental standard deviations, with both X-ray reflectivity and interfacial tension measurements. However, the agreement with the differential capacitance measured by impedance spectroscopy, and modeled by the Randles equivalent circuit, is not as good. Values of measured and calculated differential capacitance can deviate by as much as 20% for applied electric potential differences larger than approximately ±100 mV. These comparisons indicate that our understanding of the ion distributions that underlie these measurements is adequate, but that further understanding of the modeling of impedance spectroscopy data is required for quantitative agreement at larger applied electric potential differences. Ion distributions at interfaces underlie many electrochemical and biological processes, including electron and ion transfer across biomembranes and liquid interfaces, phase transfer catalysis and solvent extraction. The interface between two immiscible electrolyte solutions (ITIES) has been used as a model system to study ion and electron transfer across liquid-liquid interfaces by electrochemical techniques.1,2 These techniques characterize the interfacial ion distribution in terms of integrated properties such as interfacial excess charge or differential capacitance, which can be calculated by integrating the ion distribution over the spatial coordinate perpendicular to the interface.The differential capacitance of ITIES has been widely investigated.3-5 Impedance spectroscopy data for ITIES are often modeled by the Randles equivalent circuit to yield the interfacial differential capacitance. 6 Although this model is convenient in many circumstances, its limitations have been discussed in the literature. For example, Samec and co-authors reported limited agreement between the results from interfacial tension and impedance spectroscopy measurements of the interface between aqueous and 1,2-dichloroethane (DCE) electrolyte solutions and suggested that the Randles equivalent circuit might be at fault at high electric potential differences. 7,8 Impedance spectroscopy studies of ITIES have measured interfacial differential capacitance that depends on the nature of the ions. 4,[9][10][11][12][13][14] Interfac...

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Section: Discussionmentioning

confidence: 99%

Section: 32mentioning

confidence: 99%

Section: 32mentioning

confidence: 99%

Section: 32mentioning

confidence: 99%

Section: 32mentioning

confidence: 99%

See 3 more Smart Citations

Ion Distributions at Electrified Water-Organic Interfaces: PB-PMF Calculations and Impedance Spectroscopy Measurements

Hou

Luo

et al. 2015

J. Electrochem. Soc.

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Free‐Standing Phytantriol Q²²⁴ Cubic‐Phase Films: Resistivity Monitoring and Switching

et al. 2017

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Phytantriol Q 224 cubic phase, as a bicontinuous meso-structured material stable in contact with aqueous electrolyte, has found applications in drug delivery and cosmetics and is employed here as a free-standing film separating two aqueous compartments in order to study i) ion conductivity (at low potential bias within AE 0.8 V), ii) conductivity switching effects (at high potential bias beyond AE 0.8 V), and iii) phase switching effects (as a function of temperature). A microhole of approximately 20 mm diameter in a 6 mm thick poly-ethylene-terephthalate film is employed as the support coated with phytantriol (on a single side or on both sides) in contact with aqueous electrolyte phase on both sides in a classic four-electrode measurement cell. The conductivity of the phytantriol phase within the microhole is shown to be ionic strength, applied potential, time/history, and temperature dependent. The experimental data for asymmetric phytantriol deposits are indicative of a microhole resistance that can be switched between two states (high and low resistance associated with a filled or empty microhole, respectively). When heating symmetrically applied films of phytantriol, Q 224 -to-H II phase transition linked to a jump to a higher specific resistivity is observed, which is consistent with differential scanning calorimetry data for this phase transition.

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Bovine Serum Albumin Adsorption at a Polarized Water/1,2‐Dichloroethane Interface with No Effect on the Ion Transfer Kinetics

2022

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Adsorption of bovine serum albumin (BSA) at a polarized water/1,2‐dichloroethane (DCE) interface is examined by measuring the dynamic interfacial tension γ at various cell potentials E, BSA concentrations and pH of the aqueous phase (w). An addition of BSA to the phase (w) results in an appreciable decay ofγ with time in the whole potential range available, which follows an induction period at the very beginning of the γ transient. An analysis of the effect of the BSA concentration on the γ transients enables to establish the adsorption isotherm, and to evaluate both the maximum surface excess concentration of BSA and the standard Gibbs energy of adsorption. An increase of the potential E results in an acceleration of the adsorption, and an increase of the surface excess concentration of the positively charged BSA at pH 2, while the latter effect is absent when BSA is charged negatively at pH 7.3. It is shown that the adsorbed BSA has a negligible effect on both the interfacial capacitance of the polarized water/DCE interface and the rate constant of the interfacial transfer of the tetraethylammonium (TEA+) or Cs+ ion measured at the corresponding standard ion transfer potential.

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Some aspects of impedance measurements at the interface between two immiscible electrolyte solutions in the four-electrode cell

Cited by 12 publications

References 25 publications

Ion Distributions at Electrified Water-Organic Interfaces: PB-PMF Calculations and Impedance Spectroscopy Measurements

Ion Distributions at Electrified Water-Organic Interfaces: PB-PMF Calculations and Impedance Spectroscopy Measurements

Free‐Standing Phytantriol Q²²⁴ Cubic‐Phase Films: Resistivity Monitoring and Switching

Bovine Serum Albumin Adsorption at a Polarized Water/1,2‐Dichloroethane Interface with No Effect on the Ion Transfer Kinetics

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Some aspects of impedance measurements at the interface between two immiscible electrolyte solutions in the four-electrode cell

Cited by 12 publications

References 25 publications

Ion Distributions at Electrified Water-Organic Interfaces: PB-PMF Calculations and Impedance Spectroscopy Measurements

Ion Distributions at Electrified Water-Organic Interfaces: PB-PMF Calculations and Impedance Spectroscopy Measurements

Free‐Standing Phytantriol Q224 Cubic‐Phase Films: Resistivity Monitoring and Switching

Bovine Serum Albumin Adsorption at a Polarized Water/1,2‐Dichloroethane Interface with No Effect on the Ion Transfer Kinetics

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Free‐Standing Phytantriol Q²²⁴ Cubic‐Phase Films: Resistivity Monitoring and Switching