1,721,013 research outputs found
Impedance spectroscopy analysis of an electrolytic cell limited by Ohmic electrodes: the case of ions with two different diffusion coefficients dispersed in an aqueous solution
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Determination of the effective spaly-bend eleastic constant of a lyotropic nematic liquid crystal
No full textTheory of small-signal ac response of a dielectric liquid containing two groups of ions
No full textThe analysis of Macdonald for electrolytes is generalized to the case in which two groups of ions are present. We assume that the electrolyte can be considered as a dispersion of ions in a dielectric liquid, and that the ionic recombination can be neglected. We present the differential equations governing the ionic redistribution when the liquid is subjected to an external electric field, describing the simultaneous diffusion of the two groups of ions in the presence of their own space charge fields. We investigate the influence of the ions on the impedance spectroscopy of an electrolytic cell. In the analysis, we assume that each group of ions have equal mobility, the electrodes perfectly block and that the adsorption phenomena can be neglected. In this framework, it is shown that the real part of the electrical impedance of the cell has a frequency dependence presenting two plateaux, related to a type of ambipolar and free diffusion coefficients. The importance of the considered problem on the ionic characterization performed by means of the impedance spectroscopy technique was discussed. (c) 2008 American Institute of Physics
Tetragonal structure induced by wetting at the interface between a solid substrate and a lyotropic sponge phase
No full textStability of the uniform alignment of lyotropic nematic liquid crystals doped with magnetic grains
No full textRestricted Access.The stability of the uniform alignment of lyotropic nematic liquid crystals doped with magnetic grains is theoretically analysed. The sample is assumed to be prepared in a uniformly magnetized state by means of an external magnetic field, which is switched off subsequently. We show that there is a critical concentration of magnetic grains above which the distorting effect of the magnetic interaction overcomes the stabilizing effect of the steric interactions among grains and micelles
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