Interface conductivity

FIGURE 2.12 Effect of Ni content on the electrode/electrolyte interface conductivity (aE) and the ohmic resistance (Wohm) for Ni-YSZ cermet anodes prepared using NiO-YSZ powder mixtures precalcinated at 1400°C and sintered at 1500°C. (From Kawada, T. et al.,./. Electrochem. Soc., 137 3042-3047, 1990. Reproduced by permission of ECS-The Electrochemical Society.)... 

Polymer hypothesis Stereoregulation of polymer structure Organization of polymer chains Synthesis on a solid matrix Polymer structure and control at interfaces Conductive polymers... 

The increasing importance of multilevel interconnection systems and surface passivation in integrated circuit fabrication has stimulated interest in polyimide films for application in silicon device processing both as multilevel insulators and overcoat layers. The ability of polyimide films to planarize stepped device geometries, as well as their thermal and chemical inertness have been previously reported, as have various physical and electrical parameters related to circuit stability and reliability in use (1, 3). This paper focuses on three aspects of the electrical conductivity of polyimide (PI) films prepared from Hitachi and DuPont resins, indicating implications of each conductivity component for device reliability. The three forms of polyimide conductivity considered here are bulk electronic ionic, associated with intentional sodium contamination and surface or interface conductance. 

Table II. Lateral Interface Conductance Test Results.

In Figure 16-6 b, the interface at = 0 controls the reaction kinetics. If L denotes the interface conductivity coefficient, the rate of A uptake is given by L-A//a( = 0). For long times, the sensor registers a first order rate law E(t) e /T, r = (c°A-A )/(L-R T). This result is obtained for the linear geometry of Figure 16-6. In this context, we mention the a->P transformation of Ag2S as discussed in Sec-... 

Updated to reflect substantial developments and advances that have occurred in the past few years, this third edition unlocks a world of potential for integrating and interfacing conductive polymers. 

The observed relationship between the conductivity and film thickness can be explained as a superposition of YSZ/MgO interface conductivity, (c7j) and YSZ lattice, (cr ) contributions. An analysis of these contributions to the total conductivity, (a) has been performed using a rule... 

A difference in the bulk conductivity of the micro- and nanochannels results from the doublelayer overlap, even if they are filled with the same buffer. At low buffer concentrations, the interface conductivity (at the nanochannel) starts to dominate over the conductivity of the buffer ions. This results in a current being carried by different ratios of cations to anions in a nanochannel compared to a microchannel. Assuming that A+ and B have equal concentrations in the microchannel, the relationship between the ion fluxes in the microchannel (J ) and nanochannel (J ) for the cations can be described as ... 

Figure 50.37 has four cross-sectional planes, xi, yi, y2, and X2, respectively. The two x-cross-sectional planes represent the current passing through the microchannels and the two y-planes represent the current through the nanochannel. xi and yi are at the cathode end and X2 and y2 are at the anode end. At both x-planes, where no double-layer overlap exists, the current is carried by two cations and two anions. At both y-planes, where the interface conductivity starts to dominate the bulk conductivity, the current is carried by three cations and one anion. This results in an ion-enrichment at the cathode side and an ion-depletion at the anode side for both cations and anions. 

Further fine-tuning of the physicochemical and chemical properties of the derivatives allows for their use for extraction of cations, sensing at surfaces and interfaces, conducting of polymers, and specific-site targeting in biological macromolecules. 

Isothermal constant-mass work. Let the interface remain impermeable, thermally conducting, and movable, as above. But now adjust the reservoirs so the phases have the same temperature thereafter, the interface conducts heat in response to any (differential) temperature difference so that T = TP = constant. Then further adjust the reservoirs so the phases initially have different pressures the pressure difference moves the interface, so one phase does work against the other. Under these conditions, the closed-system form (7.2.10) of the combined laws reduces to... 

Kuhn, H.H. 1997. Adsorption at the liquid/solid interface Conductive textiles based on polypyrrole. Text Chem Color 27 17. 

Further information about the interface states can also be extracted from the impedance data. From measured values of the total conductance G and capacitance C, the interface conductance can be calculated at any given potential after correcting for the solution resistance according to (Diot et al. [1985])... 

The interface conductance can be understood, then, simply as the energy loss associated with this RC circuit such that R C = Tu or G = The loss will be a maximum when the applied frequency reaches resonance with the characteristic time. In that case, Gplm will reach a maximum value. For the case of weak inversion in the semiconductor, the maximum will occur when (OXi, = 1 and (Gpl(o)m3,x will equal Cu/2. The number of interface states Nu is given by CJe. 

Heat transfer at the interfacial surfaces is complex and involves radiation, convection, and at the covered bed/covered wall interface, conduction as well. Although a heat transfer coefficient can be allocated to each transport path shown in Figure 8.8 (Gorog et al., 1983) this should not obscure the difficulty associated with realistic determination of values for these coefficients. As mentioned earlier, the one-dimensional model is required only to produce a framework from which to operate... 

Abidian, M. Ludwig, K. Marzullo, T. Martin, D. Kipke, D. Interfacing conducting polymer nanotubes with the central nervous system Chronic neural recording using poly(3,4-ethylenedioxythiophene) nanotubes. Arfv. Mater. 2009, 21, 3764-3770. 

Relatively homogeneous fullerene LB films can be formed by mixing with arachidic acid [333]. This mixed film was used to construct a heterostructure with a PHT-arachidic acid layer, although no (bi)polaron formation was observed [341]. Donor-acceptor complexes of Cso with tetra(hexadecylthio)-TTF and BEDT-TTF were subjected to LB work. In both cases, multilayer film was formed at the air-water interface. Conductivity values of 4 and 20 S/cm for the tetra-(hexadecylthio)-TTF/C6o and the BEDT-TTF/Ceo system, respectively, were obtained after iodine doping of LB films [342]. 

The change of interface conductivity of another WORM device comprising an approximately 250 nm thin layer of FEDOTFSS sandwiched between Au electrodes was discussed by de Brito et al. in a different way. The authors observed delamination between Au and the polymer due to electrolysis of water and subsequent bubble formation. ... 

Clay and grain surface phenomena create a double layer or interface conductivity . The electrical double layer can be described with the Gouy-Chapman model or the Stem model. A detailed description of the physical properties and processes in the interface region is given by Revil et al. (1997) and Revil and Glover (1998). 

The additional interface conductive component was also detected in unconsolidated porous rocks. For example, Repsold (1976) found a dependence of the formation factor on water conductivity in sand, particularly in fine sand. Studies by Rink and Schopper (1974), Pape and Worthington (1983), and Bomer and Schon (1991) of various consolidated and unconsolidated sediments leads to an explanation of the second conductive component of rocks based on the specific internal surface, pore wall morphology, and surface charge density. 

Excess or interface conductivity also occurs in carbonate rocks but with a general low magnitude (Gegenhuber et al., 2014 Saner and Akbar, 2010). 

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