Electrical Properties of Surfaces

Electrokinetic processes are widely used in different fields of science and technology. We had already mentioned the use of electrokinetic processes for research into the electric properties of surface layers of insulating materials. Such measurements are used, in particular, when studying the surface properties of polymeric materials, their behavior in different media, and their interactions with other materials (e.g., with adsorbing surface-active substances). The results of this research are used in textile, cellulose and paper, and other industries. 

Here, AP is the applied pressure and is the electrical conductivity of the electrolyte (in Q rn ). Streaming potential measurements are routinely used to characterize the electrical properties of surfaces (e.g. [104]). 

The purpose of this study was to explore the interaction between slurry particles and wafer surfaces by the measurements of their zeta potentials. The zeta potentials of slurry particles such as fumed and colloidal silica, alumina, ceria and MnOj and substrates such as silicon, TEGS, W, and A1 have been measured by electrophoretic and electroosmosis method to evaluate the electrical properties of surfaces, respectively. The zeta potential of oxide and metal surfaces showed similar values to those of particles as a function of pH. The interaction energy between alumina and silica particles and TEOS, W and A1 substrate were calculated based on DLVO theory. No deposition of silica particles on TEOS and the heavy deposition of alumina particles on metal substrates were observed in the particle deposition test. Experimental results were well agreed with the theoretical calculation. 

Recently, xenon has been used as a nonreactive probe of surface structure. As long as the surface can be cooled to a low enough temperature to adsorb this inert gas atom, its local interaction with surface sites of different structure yields large enough variations in its heat of adsorption to be used as a probe of the surface structure. As we shall see in the chapter on electrical properties of surfaces, the surface electric dipole varies from site to site, depending on the structure of the site. This electric dipole influences the polarizability and thus the bonding of adsorbed atoms or molecules at that site. 

The function of impedimetric sensors consists of the electrical properties of an electrode change, with its svurface properties. The electric properties of surface modified electrodes can be probed by means of impedance spectroscopy. ... 

The aim of these studies is to understand and control the electrical properties of surfaces on a micrometric scale, that might be extremely useful for the application of these materials in the field of liquid crystal display (LCD) technology. In fact, it is well known that the LC anchoring properties depend not only on the substrate morphology but also on its electrical properties [68]. The electric polarization in nematic and other non-polar liquid crystals has essentially three origins flexoelectricity [65], orderelectricity [66,67] (related to the gradient in the order parameter) and the polarization of the substrate... 

The subject of surface films on electrodes in non-aqueous solutions is mostly important for the field of batteries. The performance of both Li and Li-ion batteries depends strongly on passivation phenomena that relate to surface film formation on both the anodes and the cathodes. Lithium and lithiated carbon anodes reduce all the solvents and salt anions in electrolyte solutions relevant to Li batteries. The products of these surface reactions always contain insoluble Li salts that precipitate on the electrodes as surface films. All charge transfer processes of Li, Li-C, and Li alloy anodes in Li batteries involve the critical step of Li-ion migration through the surface films. Thereby, the composition, structure, morphology, and electrical properties of surface films on Li, Li-C, and Li alloy electrodes were smdied very intensively over the years. In contrast, reversible magnesium electrodes can function only in surface film-free conditions. ... 

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