Kinetic polarization deficiency in electrolyte solutions.

Abstract

The prediction and experimental confirmation of a previously unsuspected kinetic effect occurng in electrolyte solutions are presented herein. Kinetic polarization deficiency may be described as a reduction, with respect to the pure solvent, in the static permittivity of the solution; the decrement in E0 is shown to be proportional to the product of the dielectric relaxation time of the solvent and the low frequency conductivity of the solution. The kinetic ion-solvent interaction affects the capacitive admittance in two closely related ways: as an ion migrates, the surrounding volume elements of the liquid tend to rotate according to the laws of hydrodynamics, and although dielectric relaxation tends to restore an equilibrium polarization appropriate to the local electric field, this adjustment is not instantaneous; rather it lags behind by the dielectric relaxation time. Conversely, the force that an external field exerts on an ion does not develop its full strength instantly because the ion is driven partly by the external field and partly by the polarization that develops in response to the applied field, the polarization field evolving wit a time constant that is the relaxation time for the orientation of solvent dipoles.We wish to report the theoretical prediction and experimental confirmation of an effect occurring in electrolyte solutions for which we have coined the term "kinetic polarization deficiency." For the purpose at hand the phenomenon may be described as a reduction, with respect to the solvent, in the static permittivity of the solution. Assuming, as we shall, a simple Debye dispersion for the dielectric relaxation of the pure solvent, the decrement in Eo will be shown to be proportional to the product of the relaxation time of the solvent TD and the low frequency conductivity of the solution fo.The theoretical framework is as follows: we regard not only the polarization of the vacuum, but also the intrinsic polarization of molecules and ions as occurring on a much shorter time scale than TD, thereby contributing to the high frequency dielectric constant e. On the other hand, since we are concerned only with ion-solvent interactions, the static and kinetic influences on the ionic atmosphere will also be neglected. The model we adopt is that of a symmetrically charged impenetrable sphere (the ion) moving in a viscous, incompressible, polarizble fluid continuum (the solvent) under the influence of a periodic external field. Of course, no continuum model that includes dielectric relaxation can avoid the following inconsistency: that a finite relaxation time implies finite dimensions for a fluid element.If the ion is fixed with respect to the solvent, the latter supports a static polarization field PD, which is the vector sum of the field of the ion Po, plus the image charge-induced polarization emanating from the conducting planes which, we assume, enclose the system. The specification of the compensating image charges is absolutely necessary inasmuch as this insures the convergence of t...

Dynamics in Organic Ionic Liquids in Distinct Regions Using Charged and Uncharged Orientational Relaxation Probes

“…The actual contribution will most likely be significantly smaller because the RTIL solvents are charged resulting in a reduction caused by the kinetic polarization deficiency and shielding. 42 With rotational frictions that exceeds stick boundary conditions by greater than a factor of 2 (see Table 4), the dielectric friction alone cannot account for the observed superstick results. Figure 5 shows the fluorescence spectra of MPTS in the three RTILs and in DMSO and water.…”

Dielectric properties of nonaqueous electrolyte solutions

“…(7) should result in an increase of the static permittivity of the electrolyte solution. With reference to the work of van Beek and Mandel (8) several authors take this effect into account when interpreting experimental results (7,57). However, no significant contribution of the Debye-Falkenhagen effect is detectable within the experimental accuracy of complex permittivity measurements (6,11,29,36,53), see also Cavell's argument (61).…”

Role of Water in Actin–Myosin Binding and Actin Polymerization: Rotational and Translational Mobility of Water Molecules

“…with the volume fraction 2 after the fitting process of ) ( [20][21][22][23][24][25][26]. In the analysis in the previous paper [19], spectra for actin […”

“…Note that kinetic depolarization effects in electrolyte solutions [23]. may appear in the sub-GHz range and would be included in a series of Debye functions in Eq.…”

“…However, it was misleading when their hydration volumes differ. Here we reexamined the spectra using the latest analytical method [20][21][22][23][24][25][26][27], as presented in eqs. (1)- (5), under fixed , introducing a bulk water component in the volume fraction ( > 0) to quantify the effect of the solute on the surrounding solvent of the same volume.…”