Kink model

On an atomic scale, metal surfaces are usually described in terms of the terrace-ledge-kink model shown in Fig. 20.36Z>. Essentially, it is suggested that clean metal surfaces consist of low-energy low-index terraces separated by ledges of monatomic height which occasionally contain monatomic kinks. 

Fig. 20.36 (a) Grains of different orientation intersecting a free surface and (b) the lerrace-ledge-kink model of a free metal surface... 

The simplest model of a surface with defects is the terrace-ledge-kink model. In this model only 4 types of defects are assumed present in the surface ... 

The extended chain is another conformation which has been discussed often and proved to exist—e.g., in linear polyethylene crystallized at high pressures. It has also been assumed for amorphous polymers in the form of strands of parallel molecules [kink model (57)]. The maximum length L (x-ray) of a sequence of vinyl monomers of basic molecular weight M0 is 2.52 A. Straight strands of molecules can be... 

Up to this point, only the structure of surfaces in terms of the terrace step kink model has been considered. FEED... 

Based on the TLK (terrace, ledge and kink) model, growth on a perfect vicinal and singular surface proceed by a sequence of steps involving adsorption from vapor to form a surface adatom. This adatom diffuses to a kink site of the surface and incorporate into the crystal at the kink site. In order to determine the growth rate, the rate of formation of stable cluster must be determined. This is the rate at which cluster of radius r grow by the addition of one incremental atom from the adlayer. The rate is given by. 

For the plasma sample PT0X-40P, D = 650 X and G = 1.25%. By contrast, the comparable radiation samples have values of 550 X and 0.7%, respectively. The longitudinal dimensions for both samples are considerably shorter than the extended length of the microfibril, which is of the order of 10 X. The most likely interpretation for this observation is that the type of defects suggested by the kink model ( 7) must exist in the chain direction. 

Now a roughening of such a vicinal surface means that kinks may occur on the steps and these steps may shift relative to the neighboring ones. There is now ample evidence that roughening transitions of surfaces such as Cu(l 13) do occur (e.g., Liang el al., 1987 Salanon et al, 1988 Lapujoulade et al., 1990) and that these observations can be understood in terms of terrace-step-kink models (Selke and Szpilka, 1986) and related continuum models, where an effective step-step interaction is taken into account (Villain et al.. 1985). 

Fig. 10 Kink models for chain stretches of PAN including m configurational diads in a prevailing syndiotactic configiu tion. Kinks with conformational sequence G TG T shorten the chains while maintaining the trans-planar portions of chain parallel, but not coaxial, on both sides of the defect...

Standard deviation of the lateral positions of defective units, the lateral encumbrance, t, of kink defects (defined in Fig. 25) was esteemed to be about 1.6 A, in a good agreement with the lateral encumbrance of the kink model proposed in [105] by Petraccone, Allegra and Corradini. 

Ginzburg, V.V., Gendelman, O.V., and Manevitch, L.I. (2001) Simple kink model of melt intercalation in polymer-clay nanocomposites. Phys. Rev. Lett., 86, 5073-5075. 

In the pioneering simulations, the head groups of lipids were constrained on the plane surface. No explicit water molecules were included. Artificial and simple conformations and distributions of chains were used for the initial coordinates. Those simple simulations were, however, realistic enough to produce phase transitions of lipids, and elucidated details countering the kink model which was then a widely accepted... 

Fig. 2.18. Kink-model representation of (a) bundles of chains and (b) oriented fibers with sandwich-like structure (after [10, 111).

The close geometrical description of the arrangement of chain molecules within bundles offered by the kink-model have been used by Kroner and Anthony [14g,... 

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