Interlayer diffusion

J.G. Amar and F. Family, Step barrier for interlayer-diffusion in Fe/Fe(100) epitaxial growth,... 

Figs. 11.5 and 11.6 show eight XRD patterns as measured along row C. In Fig. 11.5, the dominant (111) diffraction peak for 100% Pt appears at around 20=40°, as expected. The absence of diffraction peaks of pure Pt or Fe in the multi-metal XRD patterns is indicative of complete alloying of the multi-metal thin films by interlayer diffusion. 

Figure 32 STM topographs of 5-ML Pt deposited on a (a) clean and (b) oxygen precovered Pt(l 11) surface at 400 K. The imaged area is (220 x 220 nm ) for both images. The percentage of completion of the deposited layers versus the layer number n is plotted as histograms below each topograph. For the oxygen precovered surface, a completion of layers is favored before new layers nucleate, indicating a reduced interlayer diffusion barrier. (From Ref. 67.)...

Oxygen reduces the diffusion barrier for interlayer diffusion of Pt and a more perfect, layer-by-layer growth is achieved. 

Wood KC, Chuang HF, Batten RD, et al. Controlling interlayer diffusion to achieve sustained multiagent delivery from layer-by-layer thin films. Proc Natl Acad Sci U S A 2006 103 10207-10212. 

Returning to the smectic A arrangement, then introduction of hexagonal symmetry within the layers produces a more ordered molecular arrangement assigned as the smectic B phase (Sb). Again the phase is fluid and interlayer diffusion occurs, although rotation about the molecular axis is concerted. In a similar manner to the way that the molecules in the smectic C phase are tilted compared to the smectic A,... 

Metal chalcogenides of general formula, MX(M = Cd, Zn, etc. X = S,Se,orTe)are important in a variety of appKcations ranging from solar cells to chemical/biological sensors. While thin films of these materials can be prepared by many methods (e.g. vacuum evaporation, chemical bath deposition), electrodeposition is an attractive alternative because of its simplicity, low cost, ambient temperature operation (and consequently the absence of interlayer diffusion), and its amenability to large and irregular area coatings [1]. 

The kinetics of intercalation and deintercalation of alkali metal ions were investigated in pressure-jump experiments while monitoring the electrical conductivity of the samples (32). These studies indicate biphasic kinetics whose magnitudes are in milliseconds the rates of the fast and slow components increased with increased concentrations of the metal ions. The forward and reverse rates depend on the interlayer distances, and the fast and slow components have been attributed to the ingress of ions into the galleries and interlayer diffusion, respectively. Similar biphasic kinetics on millisecond-second time scales were also observed in pressure-jump experiments for the deprotonation-reprotonation of a-ZrP (33). In the latter case, the slow and fast components have been attributed to deprotonation from the surface and from the interlayer regions of the solid, respectively. 

Glaus MA, Baeyens B, Bradbury MH, Jakob A, Van Loon LR, Yaroshchuk A (2007) Diffusion of Na and Sr in montmorillonite evidence of interlayer diffusion being the dominant pathway at high compaction. Environ Sci Technol 41 478-485... 

Without interlayer With interlayer Without interlayer With interlayer diffusion diffusion diffusion diffusion... 

Gilbert, J.B., Rubner, M.F., Cohen, R.E. Depth-inofiling X-ray photoelectron spectroscopy (XPS) analysis of interlayer diffusion in polyelectrolyte multilayers. Proc. Nat. Acad. Sci. USA 110, 6651-6656 (2013)... 

Figure 31.12 displays the desirable skin morphologies at various locations of dual-layer membranes. Briefly, both the inner and outer skins of the inner layer are porous with intimate adhesion between them. When using two different materials, one can control the interlayer diffusion as a function of spinning conditions. Table 31.2 summarizes the elemental analysis data of the interfacial layers of hollow fibers spun from PES as the inner layer and Matrimid polyimide as the outer layer at different spinneret temperatures (Jiang et al., 2004). After being extruded from the spinneret, the two dopes should make contact with each other under normal conditions. When the spinneret temperature is low (i.e., 25°C), their viscosities are high, the diffusion rate of the polymer molecules between the two layers will not be fast therefore, no sulfur can be found in the outer layer, as shown in this table. When the spinneret temperature is increased to 60°C, the interlayer diffusion between the two polymers apparently occurs, as evidenced in Table 31.2, in which it is... 

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