Bulk domain

FIGURE 10.12 The mole ratio of carotenoid/phospholipid and carotenoid/total lipid (phospholipid + cholesterol) in raft domain (detergent-resistant membrane, DRM) and bulk domain (detergent-soluble membrane, DSM) isolated from membranes made of raft-forming mixture (equimolar ternary mixture of dioleoyl-PC (DOPC)/sphingomyelin/cholesterol) with 1 mol% lutein (LUT), zeaxanthin (ZEA), P-cryptoxanthin (P-CXT), or P-carotene (P-CAR). 

FIGU RE 10.13 Schematic drawing of the distribution of xanthophyll molecules between raft domain (DRM) and bulk domain (DSM) in lipid bilayer membranes. For this illustration, the xanthophyll partition coefficient between domains is the same as obtained experimentally for raft-forming mixture. However, to better visualize the observed effect in the drawing, the number of lipid molecules was decreased and the total number of xanthophyll molecules was increased about 10 times. (From Wisniewska, A. and Subczynski, W.K., Free Radio. Biol. Med., 40, 1820, 2006. With permission.)... 

Kawasaki, K., J.-J. Yin, W. K. Subczynski, J. S. Hyde, and A. Kusumi. 2001. Pulse EPR detection of lipid exchange between protein-rich raft and bulk domains in the membrane Methodology development and its application to studies of influenza viral membrane. Biophys. J. 80 738-748. 

Figure 3.8. Dynamic redox experiments in propylene oxygen mixtures around the same sample area m (a) fresh catalyst (b) domains (c) bulk domains with CS nucleation (arrowed) and (d) CS planes. The domains and CS planes are formed even in the presence of oxygen gas (after Gai 1981).

Figure 3.10. Reduction of the catalyst (001) in H2/He (a) surface domains at 100°C with ED showing disorder (b) bulk domains with varying trace boundaries (leading to the V4O9 structure).

Other examples of the exploitation of shake up phenomena includes for example the investigation of the relationship of surface to bulk domain structure in AB block copolymers41. These studies considerably extend the scope of ESCA as one of the most important shots in the polymer chemist and physicists locker for studying aspects of structure, bonding and reactivity relating to the surface regions of polymers. 

Fig. 2.56 Beating of Kiessig fringes observed using X-ray reflectivity from a PVP PS-PVP tri block copolymer film (fes = 0.48, Mv = 120 kg mol ) with two discrete thicknesses of 1935 and 2229 A (de Jeu et al. 1993). The difference in height results from island and hole formation at the free surface, and is equal to the bulk domain spacing.

Fig. 12 Diagram of structures for varying interaction of the compounds with the top ( m ) and bottom ((mi) interface. Symbols denote the structures that are shown as insets. Isodensity profiles for Pa = 0.45 are shown, and the thickness h is twice the bulk domain distance ais (co in [59]). Reprinted from [59], with permission. Copyright 2004 American Institute of Physics...

Although a number of techniques have been devised to investigate the bulk domain structure of multicomponent polymer systems the detailed structure of the surface, i.e., the outermost few tens of angstroms, has been studied in much less detail. Since many of the important properties of a polymeric solid are dependent upon the surface structure and since the surface can differ considerably from the bulk a technique which can differentiate the surface from bulk properties is likely to be of considerable importance. 

The most general approach to afford stable nanopartides via solid-state assembly relies on the use of block copolymers composed of a cross-linkable/gelable block and a soluble segment. The block polymer is cast from a good solvent for both blocks followed by annealing to yidd a segregated thin film in which mesostructures of the cross-linkable block are surrounded by a matrix of soluble block. When a diblock copolymer, A -b-Bm, is assembled in bulk, domains of B on the nano- or microscale distributed in a matrix of A will form... 

The composition profile in depth direction was investigated using a 3D model, whereby a checkerboard stmcture was observed in the early stages of decomposition, but this decayed as the intrinsic value of R(f) in the bulk domain increased. The strip patterns were confined to the surface domain in the later stages of phase decomposition. A consideration of the isotropic elastic energy also caused a slower evolution in the depth direction. 

Compatibility to the functionalized substrate of the morphology on the layers through the depth is plotted at different time spots. The depth of the film in the time spot concerned is divided by 16 nodes. In the case considering evaporation, there was no significant change in the value of Cj in the depth direction, but in cases with a constant solvent composition the compatibility alternated from the surface to the bulk domain, which indicates that the dominant polymer type had changed from the surface to the depth. This result was in accordance with the checkerboard structure in the depth direction. As stated above, the surface attraction can affect only the neighboring surface of the ternary blends, and the domain that is not connected to the substrate is influenced only indirectly. The influence of the functionalization decays very quickly into the depth from the substrate surface. 

So far, tbe surface excess of a solute species was considered on tbe surface of a bulk phase, e.g. water, air, solid adsorbent, etc. Tbe surfaces of macromolecules, especially proteins, bave an interfacial region, sometimes called the local domain, which can have compositions different from the bulk domain, namely the bulk of the solution. For example, the bulk of an aqueous protein solution may have cosolvents (or cosolutes) such as urea, guanidine... 

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