Impedance spectroscopy measurements

Figure 5 presents the capacitance-frequency dependence from impedance spectroscopy measurements for CS48 and CS15 in acidic and organic medium. In the low frequency region (from ImHz to lOOmHz) nearly a complete penetration of the ions into the pores is allowed and the quite stable values indicate the domination of the capacitive behavior at the electro 1 ytc/carbon interface. All the curves show a typical drop of... 

Fig. 1 Representative a Nyquist and b Bode plots from electrochemical impedance spectroscopy measurements (HubrechtJ (1998) Metals as Biomaterials, Helsen J, Breme H (eds) John WUey Sons Limited. Reproduced with permission)...

Impedance Spectroscopy Measurements of Silicone Rubber Membranes... 

To evaluate the crystallinity of the films, Raman spectroscopy is used. A typical Raman spectrum is presented in Fig. 4. Of the crystalline diamond, a narrow peak at a frequency of 1332 cur1 is characteristic, which is caused by the first-order phonon scattering by the crystal lattice. The non-diamond carbon is represented in the spectrum by two diffuse bands at ca. 1350 and 1550 cm-1. When comparing the peaks height, one should keep in mind that the Raman signal is 50 times more sensitive to the non-diamond carbon than to the crystalline diamond [20], In the high-quality diamond films used as electrodes, the non-diamond carbon component rarely exceeds 1%. Raman spectroscopy data have been corroborated by the independent impedance spectroscopy measurements (see below). According to [21], the inner layer of a diamond film is enriched with the admixture of non-diamond carbon as compared to its outer layer. 

The best method to measure the double-layer capacitance is to use a phase-sensitive voltmeter. This instrument is sometimes incorporated into a frequency response analyzer, designed to make electrochemical impedance spectroscopy measurements, but it can also be used independently. In Part Two we devote a full section to the operation of such instruments and the analysis of results obtained by them. Here we shall limit the discussion to the measurement of capacitance. 

Initial evidence for the intermediacy of surface states came from dark current measurements on n-Ti02 and n-SrXi03 in the presence of oxidizing agents such as [Fe(CN)6] ", Fe +, and [IrCle] [177, 178]. Similar evidence that the charge-transfer process was more complex than direct transfer of electrons from the semiconductor CB also came early from AC impedance spectroscopy measurements on n-ZnO, n-CdS and n-CdSe in contact with [Fe(CN)6] species [179, 180],... 

The surface layer formation is a crucial phenomenon as it affects the electrode charge transfer rate. Low-conductivity films determine high electrode overvoltages and lower battery performance. The charge transfer resistance can be monitored by impedance spectroscopy measurements, which represent a useful tool for the in-situ characterization of resistive and capacitive processes occurring in different time scales (1 mHz-100 kHz) [80]. 

The avidin-biotin procedure has been extensively used in hybridization studies. Since the concentration of all analysed DNAs used is identical, the total concentration of the analysed samples is high. The amplification of the base-mismatch recognition event is necessary to improve sensitivity. The use of oligonucleotide-functionahzed Uposomes or biotin-labelled liposomes as probes for the dendritic amphfication of DNA-sensing processes was characterized by Willner and co-workers [62] and showed better performance using QCM than impedance spectroscopy measurements. 

F. Zou, D. Thierry, and H. S. Isaacs, "High-Resolution Probe for Localized Electrochemical Impedance Spectroscopy Measurements," Journal of The Electrochemical Society, 144 (1997) 1957-1965. 

M. E. Orazem, T. E. Moustafid, C. Deslouis, and B. Tribollet, "The Error Structure of Impedance Spectroscopy Measurements for Systems with a Large Ohmic Resistance with Respect to the Polarization Impedance/ Journal of The Electrochemical Society, 143 (1996) 3880-3890. 

The fluid electrical conductivity a is assumed to be linearly dependent on temperature in all fluid zones and in the membrane as well. The linear law coefficients were fitted on impedance spectroscopy measurements performed over a wide range of temperatures and H2S04 concentrations. The catholyte conductivity is also dependent on the gas volume fraction a2 following the Brugge man relation ... 

Model study investigating the role of interfacial factors in electrochemical impedance spectroscopy measurements. Corrosion 2000, (7),... 

Fig. 2 presents typical hodograph curves of the cell impedance. The impedance spectroscopy measurements allowed separating contributions from electrode processes (Ri ), resistance of the grain bulk (Rbuik), and resistance of grain boundaries (Rgb) in a polycrystal. The experimental data were processed using a program [2,3], which was written by Bernard Boukamp. 

Impedance spectroscopy measurements have been used to investigate molecular dynamics in a-chitin. After dc conductivity correction, the exclusion of contact and interfacial polarization effects, and obtaining a condition of minimum moisture content ( 0.1%), the a-relaxation process that likely represents the glass transition is unveil. 

M. Grzeszczuk, Electrochemical study of polyaniUne film electrodes and their modifications impedance spectroscopy measurements on hydrogen evolution reaction, ElectrocMm. Acta, 39, 1809 1816 (1994). 

Impedance spectroscopy measures the frequency response of the electric impedance. In an impedimetrie sensor, the molecules to be characterized are adsorbed on the electrodes, or on a surface between a pair of electrodes. This process of absorption changes the electrical performance of the device. By measuring the impedance between the electrodes, some conclusions can be established. " ... 

Sarro, E., Lecina, M., Fontova, A., Sola, C., Godia, F, Cairo, J.J., Bragos, R., 2012. Electrical impedance spectroscopy measurements using a four-electrode configuration improve on-Une monitoring of cell concentration in adherent animal cell cultures. Biosens. Bioelectron. 31, 257—263. 

Fig. 2 Representative (a) complex plane diagrams (Nyquist or Cole-Cole plots) and (b) Bode plots from electrochemical impedance spectroscopy measurements...

Benavente, J., Zhang, X. and Garcta-Vails, R. 2005. Modification of polysulfone membranes with polyethylene glycol and lignosulfate Electrical characterization by impedance spectroscopy measurements. J. Colloids Interface Sci. 285 273-280. 

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