Nanopore layer transitions

A significant consistency is observed between MC simulation and SSL. Wang (Wang, 2007) also studied the layer transitions in nanopore by MC simulation and strong stretching theory. Sun et al. (Sun et al.,... 

In this work, a framework of the SSL theory for diblock copolymer melts confined in ring-like curved surfaces has been proposed. When the curvature approaches to zero, it reduces to the well-known SSL theory for the parallel lamellar phases. In the case of the equal confined thickness to the exterior radius, it can also be extended to the system with a nanopore confinement. Moreover, the Helmholtz energy of the concentric cylinder barrel, sector column and CMSC phases in 2D confinements based on this SSL theoretical framework can be evaluated in the convenient manner. The calculated results show that the diblock copolymer melts exhibit a layer-type transition with a similar mechanism, regardless of ring-like curved surfaces, planar surfaces, and nanopores. 

In this work, we have focused on strong surface preference with only mutual transition between the symmetrical and asymmetrical layer-type structures. SSL theory and MC simulation are further applied to investigate the self-assembled morphology of diblock copolymers confined in the nanopore. MC simulation shows that the Niayer of the concentric cylinder barrel changes with respect to the extent of frustration between the exterior radius Rex and the bulk lamellar period L0. Simultaneously, the predictions of SSL theory also show that both... 

Fig. 43. Complex plane IMPS plot for 14 micron thick nanoporous GaP layer on n-GaP under depletion conditions (potential 2.5V vs. SCE) in acid electrolyte (pH = 1.0). Illumination from the electrolyte side 350 nm). The steady state photocurrent efficiency is unity. The transit time r d) derived from a> i is 5 10-3 s ...

As for effective kinetic parameters of the ORR that should be used in macroscopic models, it seems reasonable to assume that the reaction order for oxygen concentration will be yo2 = 1 for conditions of interest. The effective transfer coefficient of the ORR, ac, will transition through a sequence of discrete values between 1 and 0.5, as a function of electrode potential. The reaction order for proton concentration, yh+, depends strongly on the adsorption regime and, therefore, a prediction of the value is not trivial. The difference ac - yh+ is a key determinant of electrostatic effects in water-filled nanopores inside of catalyst layers, as discussed in the section ORR in Water-Filled Nanopores Electrostatic Effects. ... 

The physical properties of materials in a confined state have attracted considerable attention both due to their fundamental significance and to their primary importance for nanotechnology. The term confined state embraces a wide variety of systems the boundary layers at the interfaces between two bulk phases, the adsorption layers, wetting films, epitaxial structures, emulsions, free-lying nanoparticles and particles embedded in solid matrices, the substances condensed in pores, and so on. As a rule, the transition of a substance from the bulk state to the confined state is accompanied by an essential alteration of many physical properties. In particular, for practically all of the confined systems mentioned above, a shift of the first order phase transition temperature with respect to that in the bulk state was detected experimentally (see [1-4] for reviews). In nanoporous systems, not only a considerable (tens of degrees) depression of the freezing temperature can be observed, but the transition to solid state might even disappear. At the same time there are systems that demonstrate not a depression but an elevation of the solid/liquid phase transition temperature in pores. A similar situation occurs with small particles, adsorbed films and boundary layers at plane interfaces. 

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