Interfacial concerns

The positive effect of ceramic fillers on the nature and properties of the lithium-electrolyte interface was recognised quite early and the first suppositions were that the filler grains can gather at the interface, decreasing the surface area between the lithium electrode and the polyether. However that supposition was discarded with the help of experiments conducted with the use of both low and high molecular weight PEO-based electrolytes (Syzdek et al. 2007). 

Other studies showed that by adjusting the surface groups the efficiency and kinetics of lithium metal plating/stripping can be enhanced. Acidic fillers were observed to be the best choice (Egashira et al 2006). 

How could that be explained One supposition is that fillers of high Lewis acidity can trap impurities/traces of water/other reactive molecules (including salt anions) (Li et al 2001) and in this way counteract secondary 

Whatever the model we assume, the experimental fact is that highly acidic fillers enhance stability and transport properties of the interfaces with low potential electrodes as presented in Fig. 2.8. 

8 Evolution of the resistance of a symmetrical lithium cell with a composite electrolyte consisting of 1M LiCI04 in 5 x 10 g/mol poly(oxyethylene) with 10% w/w 1 pm AI2O3 modified with sulphuric acid as a filler. Storage and measurements at 70°C. R el. - resistance of the electrolyte, RCT - resistance of the charge transfer, R passiv. -resistance of the passive layer, R diff - diffusion resistance. Notice initial decrease followed by a stability period of the measured impedances. This behaviour is very different from the continuous increase observed for liquid electrolytes. 

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Multiphase implementations, designed to optimize certain aspects of transport, lead to additional interfacial concerns. Last but not least, we often need to woik in non-Newtonian systems, which require a modification of the constitutive relation used in the Navier-Stokes equations. 

A large number of studies concerned witli tliiol-tenninated molecules has been directed at tire preparation of tailored organic surfaces, since tlieir importance has been steadily increasing in various applications. Films of o> functionalized alkanetliiols have facilitated fundamental studies of interfacial phenomena, such as adhesion [190, 191], corrosion protection [192], electrochemistry [193], wetting [194], protein adsorjDtion [195, 196] or molecular recognition [197, 198, 199, 200 and 201] to mention only a few. 

The traditional view of emulsion stability (1,2) was concerned with systems of two isotropic, Newtonian Hquids of which one is dispersed in the other in the form of spherical droplets. The stabilization of such a system was achieved by adsorbed amphiphiles, which modify interfacial properties and to some extent the colloidal forces across a thin Hquid film, after the hydrodynamic conditions of the latter had been taken into consideration. However, a large number of emulsions, in fact, contain more than two phases. The importance of the third phase was recognized early (3) and the lUPAC definition of an emulsion included a third phase (4). With this relation in mind, this article deals with two-phase emulsions as an introduction. These systems are useful in discussing the details of formation and destabilization, because of their relative simplicity. The subsequent treatment focuses on three-phase emulsions, outlining three special cases. The presence of the third phase is shown in order to monitor the properties of the emulsion in a significant manner. 

The important point to note here is that the gas-phase mass-transfer coefficient fcc depends principally upon the transport properties of the fluid (Nsc) 3nd the hydrodynamics of the particular system involved (Nrc). It also is important to recognize that specific mass-transfer correlations can be derived only in conjunction with the investigator s particular assumptions concerning the numerical values of the effective interfacial area a of the packing. 

One concerned with the measurement of gas-hquid interfacial tension should consult the useful reviews of methods prepared by Harkius [in Chap. 9 of Weissberger, Techniques of Organic Chemstry, 2d ed., vol. I, part 2, Interscience, New York, 1949), Schwartz and coauthors [Suiface Active Agents, vol. I, Interscience, New York, 1949, pp. 263-271 Suiface Active Agents and Detergents, vol. 2, Interscience, New York, 1958, pp. 389—391, 417—418], and by Adamson [Physical Chemistry of Suifaces, Interscience, New York, I960]. 

Jean-Baptiste Rome de I lsle (1736-1790) and Rene Haiiy (1743-1822), while they, as remarked, credited Linnaeus with the creation of quantitative crystallography, themselves really deserve this accolade. Rome de I lsle was essentially a chemist and much concerned with the genesis of different sorts of crystal, but his real claim to fame is that he first clearly established the principle that the interfacial... 

It must also be recognized that adhesive interfaces are not static entities, but may deteriorate or even strengthen over time, and often it is the time course of interfacial strength or durability under different conditions and in different environments that is of greatest concern [4]. As important as durability issues are, they too will not be a direct concern of this chapter. 

In general, p (r) is a function of the vector position of the point of observation r. However, if one is concerned mainly with the inhomogeneity of the confined fluid in the normal (z) direction, the average over the interfacial area is adequate. Averaging yields... 

In the following chapters, we will concern ourselves with the nature of the interfacial microenvironments of some polyelectrolytes whose functionality controls photoinduced ET. Emphasis will be placed on the local electrostatic potential and also on the microphase structure of some amphiphilic polyelectrolytes in aqueous solution. 

El), Oldshue (Ol), and Johnson et al. (J4)] have been concerned with the determination of the volume transfer coefficient KtAb (liter/hr), where Kx is the mass-transfer coefficient and Ab is the total gas-liquid interfacial area. The results obtained using a turbine impeller and an open pipe sparger can be correlated in terms of the nominal gas velocity wg(ft/hr) and the horsepower input to the impeller HP by an expression of the following form ... 

Later publications have been concerned with mass transfer in systems containing no suspended solids. Calderbank measured and correlated gas-liquid interfacial areas (Cl), and evaluated the gas and liquid mass-transfer coefficients for gas-liquid contacting equipment with and without mechanical agitation (C2). It was found that gas film resistance was negligible compared to liquid film resistance, and that the latter was largely independent of bubble size and bubble velocity. He concluded that the effect of mechanical agitation on absorber performance is due to an increase of interfacial gas-liquid area corresponding to a decrease of bubble size. 

This would of course have drastic consequences as far as the validity of interfacial free energies derived from LH analysis of growth rate data is concerned. 

The retarding influence of the product barrier in many solid—solid interactions is a rate-controlling factor that is not usually apparent in the decompositions of single solids. However, even where diffusion control operates, this is often in addition to, and in conjunction with, geometric factors (i.e. changes in reaction interfacial area with a) and kinetic equations based on contributions from both sources are discussed in Chap. 3, Sect. 3.3. As in the decompositions of single solids, reaction rate coefficients (and the shapes of a—time curves) for solid + solid reactions are sensitive to sizes, shapes and, here, also on the relative dispositions of the components of the reactant mixture. Inevitably as the number of different crystalline components present initially is increased, the number of variables requiring specification to define the reactant completely rises the parameters concerned are mentioned in Table 17. 

From the fundamental knowledge concerning the interfacial complexation mechanism obtained from the kinetic studies on chelate extraction, ion-association extraction, and synergistic extraction, one can design the interfacial catalysis. The main strategy is to raise the concentration of the reactant or intermediate at the interface. 

Rotational dynamics of a fluorescent dye adsorbed at the interface provides useful information concerning the rigidity of the microenvironment of liquid-liquid interfaee in terms of the interfacial viscosity. The rotational relaxation time of the rhodamine B dye was studied by time-resolved total internal reflection fluorescent anisotropy. In-plane... 

The electrical oscillations at the aqueous-organic interface or at membranes in the absence of any substances relative to the channel or gate were introduced. These oscillations might give some fundamental information on the electrical excitability in living organisms. Since the ion transfer at the aqueous-organic or aqueous-membrane interface and the interfacial adsorption are deeply concerned in the oscillation, it has been stressed that the voltammetry for the ion transfer at an interface of two immiscible electrolyte solutions is... 

When ionizabie compounds are concerned, the situation is complicated by the fact that all the species present may transfer from one phase to the other depending on the interfacial potential difference, so that the transfer process of the solute is entirely determined by the thermodynamic cycle described in Fig. 4. 

The Wilhelmy hanging plate method (13) has been used for many years to measure interfacial and surface tensions, but with the advent of computer data collection and computer control of dynamic test conditions, its utility has been greatly increased. The dynamic version of the Wilhelmy plate device, in which the liquid phases are in motion relative to a solid phase, has been used in several surface chemistry studies not directly related to the oil industry (14- 16). Fleureau and Dupeyrat (17) have used this technique to study the effects of an electric field on the formation of surfactants at oil/water/rock interfaces. The work presented here is concerned with reservoir wettability. 

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