Interfacial stability

Compared with the non-electrochemical interface discussed in the previous section, where a sofid was in contact with a surrounding gaseous atmosphere, the electrode/ electrolyte interface is a multicomponent system and, besides temperature and partial pressures/concentrations, it is also influenced by the electrode potential. This results in greater complexity, which requires additional considerations prior to deriving an expression for the interfacial stability. 

Although the extended ab initio atomistic thermodynamics approach provides an exact expression for the interfacial stability, the formalism requires self-consistent modeling of the entire electrochemical system, or electrode/electrolyte interface, exceeding presently available computational capabilities. Therefore, certain assumptions had to be made that reduce the effort to the calculation of the electrode surface only. Even with this simplified approach, which has been applied to the two examples discussed in this chapter, the qualitative behavior can be reproduced. 

Pitts, R.R., Smith, D., Lee, S., and Tracy, E. Interfacial Stability of Thin Film Hydrogen Sensors, FY 2004 Annual Progress Report, VI.3, DOE Hydrogen Program, 2004. 

Dickinson, E. (1997b). Enzymic crosslinking as a tool for food colloid rheology control and interfacial stabilization. Trends in Food Science and Technology, 8, 334-339. 

Interfacial stability has been studied by analytical means [4, 5, 9, 11-15] and also numerically [19-21], In the following, we present some of the analytical results of most immediate interest. Many other important results may be found in the... 

J.S. Langer and L. A. Turski. Studies in the theory of interfacial stability—I. Stationary symmetric model. Acta Metall., 25(10) 1113—1119, 1977. 

P.G. Shewmon. Interfacial stability in solid-solid transformations. Trans. TMS-AIME, 233 736-748, 1965. 

The purpose of this paper is to provide a broad overview of why interfacial stability is crucially important in materials used for the direct conversion of solar radiation to useful end-products in man-made col-lection/conversion systems. The importance of interfacial stability and studies of interfacial phenomena has been addressed in considerable detail in previous review articles (1-3) and in the proceedings of a workshop (4). 

Polycrystalline Films/Coatings Materials Specific Multilayer Stacks Extensive Interfaces Interfacial Stability... 

Extensive interface research is crucially essential for developing long-life, cost-effective, multilayer, polycrystalline, thin-film stacks for SECS. Microchemical analysis and other interface measuring techniques must be employed to solve the interfacial stability problems in the stacks. Important topical areas in solar materials interface science include thin films grain, phase, and interfacial boundaries corrosion and oxidation adhesion chemisorption, catalysis, and surface processes abrasion and erosion photon-assisted surface reactions and photoelectrochemistry and interface characterization methods. 

The difference of the cycling performance between the PMMA and the PAN systems should be due to the difference in the chemical stability of the Li/ gel electrolyte interface. The interfacial stability of the Li electrodes in contact with the gel electrolytes was investigated by impedance spectroscopy. Figure 6 shows the interfacial resistance (/ ,), which is estimated from the first semicircle... 

So in the crystallization of microporous systems there is a balance between the energy cost of micropore generation and the energy gain because of interfacial stabilization by occluded molecules. Clearly there is no gain for porous aluminum-free systems in water, so they will not be formed unless a trick is used. 

Y.Y. Su and B. Khomami, Interfacial stability of multilayer viscoelastic fluids in slit and converging channel die geometries, J. Rheol., 36 (1992) 357-387. 

Figure 1 Interfacial stability for freezing of typical natural lake water a) Wavelength-velocity diagram for two liquid temperature gradients Gi, and b) Stability function Sr from Sekerka for dilute NaCl solutions for a range of plausible values of k.

The alloy solidification experiments that have been performed on Spacelab missions generally fall into four categories 1) interfacial stability 2) evolution... 

Favier used the USMP-1 opportunity to explore the interfacial breakdown in Bi-doped Sn, which, like most metals, solidifies as a plane front with little kinetic undercooling. His U.S. co-investigator, Abbaschian, investigated interfacial stability on the other side of the phase diagram i.e., Sn-doped Bi, which solidifies with a faceted interface. The purpose was to test the extension of the Mullins-Sekerka stability criterion to include the effects of anisotropy, which acts to stabilize the interface against breakdown into cellular and dendritic growth. " ... 

Electrochemistry is a central theme in the interconnection of chips and other microelectronic components. The manufacture of printed wiring boards, such as single-layer, multilayer, or flexible boards, involves electroplating of the conductor that forms the electrical paths. The corrosion of these paths and the interfacial stability of the conductor-polymer composites that determine the reliability of these interconnections are electrochemical problems. 

VI.A.2 Interfacial Stability of Thin Film Hydrogen Sensors... 

To be useful, most commercial polymer blends are either designed or selected to have some degree of the technological compatibility between the components to resist delamination and loss in ductility. Compatibility is defined here as the ability for the polymer components to co-exist either as molecularly miscible or as morphologically distinct phases, but interfacially stabilized, without a tendency for delamination. 

Additional work on the fundamental mechanisms of occlusion formation under various crystallization conditions is needed. The interactions of mixing and addition rates with rates of nucleation and growth, and with interfacial stability need further elueidation. 

Interfacial stability is predicted using the ERR, which is defined as the mechanical energy that is released during an incremental increase in crack length. Crack advance occurs when the ERR reaches a critical value, often referred to as the interface toughness, denoted here as Fj. Thus, the crack growth criterion is G > Fj. The ERR is defined as [33]... 

Abstract Nanoparticles (NPs, diameter range of 1-100 nm) can have size-dependent physical and electronic properties that are useful in a variety of applications. Arranging them into hollow shells introduces the additional functionalities of encapsulation, storage, and controlled release that the constituent NPs do not have.This chapter examines recent developments in the synthesis routes and properties of hollow spheres formed out of NPs. Synthesis approaches reviewed here are recent developments in the electrostatics-based tandem assembly and interfacial stabilization routes to the formation of NP-shelled structures. Distinct from the well-established layer-by-layer (LBL) synthesis approach, the former route leads to NP/polymer composite hollow spheres that are potentially useful in medical therapy, catalysis, and encapsulation applications. The latter route is based on interfacial activity and stabilization by NPs with amphiphilic properties, to generate materials like colloidosomes, Pickering emulsions, and foams. The varied types of NP shells can have unique materials properties that are not found in the NP building blocks, or in polymer-based, surfactant-based, or LBL-assembled capsules. 

Keywords Hollow spheres Nanoparticles Layer-by-layer assembly Tandem assembly Nanoparticle assembled capsule Interfacial stabilization - Particle stabilized emulsion... 

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