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ABSTRACT: Composite polymeric electrolytes of PEO-LiClO4-Al2O3 and PEO-LiClO4-EC were prepared and the ionic conductivity by a.c. impedance was calculated using four different methods, and three kinds
of representations of a.c. impedance spectra were adopted. The first is based on the Nyquist impedance plot of the imaginary
part (Z″) versus the real part (Z′) of the complex impedance. The second and the third correspond to the plots of imaginary impedance Z″ as a function of frequency (f), and the absolute value (|Z|) and phase angle (θ) as a function of f, respectively. It was found that the values of the ionic conductivity calculated using the three representations of a.c.
impedance spectra are basically identical.
Journal of Solid State Electrochemistry 11/2001; 6(1):8-15. · 2.13 Impact Factor
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ABSTRACT: Ultrathin multilayer films of a polybasic lanthanide heteropoly tungstate-molybdate complex and a cationic polymer of quaternized
poly(4-vinylpyridine) partially complexed with osmium bis(2,2′-bipyridine) have been fabricated on a gold electrode precoated with a cysteamine self-assembled monolayer. The multilayer
films have been characterized by optical spectroscopy, small-angle X-ray diffraction, and electrochemical methods (cyclic
voltammetry and electrochemical impedance). Especially, the electrochemical impedance spectroscopy is developed to monitor
the layer deposition processes. It provides important information such as double-layer capacitance and charge-transfer resistance.
All obtained results reveal regular film growth with each layer adsorption. © 2001 The Electrochemical Society. All rights
reserved.
Journal of The Electrochemical Society. 04/2001; 148(5):E227-E232.
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ABSTRACT: A novel type of potassium sensor based on the capacitance change of valinomycin-incorporated bilayer supported on a gold electrode has been developed and characterized. The lipid membrane was formed by painted method and monitored simultaneously by capacitance variation. The capacitance of the electrode-supported membrane was found to be modulated by different concentrations of K+. Investigating the capacitance change allows a simple and specific technique for the measurement of potassium ion in solution. Especially, the homemade capacitance meter is, to our knowledge, used to monitor the bilayer membrane formation and detect K+ for the first time. It has been proved that this capacitance measurement is a very useful technique because it is simple and sensitive compared to the other methods.
Electroanalysis 01/2001; 13(1):68 - 71. · 2.87 Impact Factor
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ABSTRACT: The effects of plasticizer ethylene carbonate (EC) on the AC impedance spectra and the ionic conductivity are reported. With increasing of EC concentration the semicircle in high frequency disappears, and the slope of the straight line in low frequency decreases. The data obtained from impedance experiments can be explained using an equivalent circuit proposed. On the other hand, the room temperature conductivity increases with EC concentration because of the increase of the segmental flexibility of PEO. For lower EC concentration samples, the temperature dependence of conductivity in low temperature range follows Arrhenius type, but when EC concentration is larger than 20%, the temperature dependence of conductivity obeys the Vogel–Tamman–Fulcher (VTF) equation in all temperature ranges.
Materials Chemistry and Physics 74(1):98-103. · 2.23 Impact Factor
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ABSTRACT: A composite solid polymer electrolyte (SPE) of (PEO)10LiClO4–Al2O3 was prepared and Pt and stainless steel(SS) blocking electrodes were used for an impedance study. It was found that the semicircle in the high frequency range and the straight line in the low frequency range depend upon different blocking electrodes and polarization potentials applied in the experiments. In the equivalent circuit, two constant phase elements (CPE) have been used instead of the pure geometrical and double layer capacitances, respectively. A theoretical line calculated from their estimated values has a good correlation with the experiment data. Moreover, the equivalent circuit also can be used to explain the impedance properties of Pt and stainless steel (SS) blocking electrodes both in the high and the low frequency ranges.
Electrochimica Acta.
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ABSTRACT: A flow injection amperometric immunoassay system based on the use of screen-printed carbon electrode for the detection of mouse IgG was developed. An immunoelectrode strip, on which an immunosorbent layer and screen-printed carbon electrode were integrated, and a proposed flow cell have been fabricated. The characterization of the flow immunoassay system and parameters affecting the performance of the immunoassay system were studied and optimized. Amperometric detection at 0.0 V (versus Ag/AgCl) resulted in a linear detection range of 30–700 ng ml−1, with a detection limit of 3 ng ml−1. The signal variation among electrode strips prepared from variant batch did not exceed 8.5% (n=7) by measuring 0.5 μg ml−1 antigen standard solution.
Analytica Chimica Acta.
