Crystalline Crystallinity

There are different criterion of how to classify solid-solid interfaces. One is the sharpness of the boundary. It could be abrupt on an atomic scale as, for example, in III-IV semiconductor heterostructures prepared by molecular beam epitaxy. In contrast, interdiffusion can create broad transitions. Surface reactions can lead to the formation of a thin layer of a new compound. The interfacial structure and composition will therefore depend on temperature, diffusion coefficient, miscibility, and reactivity of the components. Another criterion is the crystallinity of the interface. The interface may be crystalline-crystalline, crystalline-amorphous, or completely amorphous. Even when both solids are crystalline, the interface may be disturbed and exhibit a high density of defects. 

Physical form Oily Liquid Crystalline Crystalline Crystalline... 

Sample CEC, meq Ba /100g ACsHs % Y zeolite PI zeolite Thermal crystallinity crystallinity stability, °C Si02/Al203 FS203 ratio wt.% FeO wt. % TiOj wt.%... 

Structure as deposited Crystalline Crystalline/ amorphous Crystalline/ amorphous Amorphous Microcrystalline/ amorphous Mcirocrystalline/ amorphous Cross-linked... 

For crystalline-crystalline interfaces we further discriminate between homophase and heterophase interfaces. At a homophase interface, composition and lattice type are identical on both sides, only the relative orientation of the lattices differ. At a heterophase interface two phases with different composition or/and Bravias lattice structure meet. Heterophase interfaces are further classified according to the degree of atomic matching. If the atomic lattice is continuous across the interface, we talk about a fully coherent interface. At a semicoherent interface, the lattices only partially fit. This is compensated for by periodic dislocations. At an incoherent interface there is no matching of lattice structure across the interface. 

Fig. 24. Line shape analysis of the equilibrium spectrum of the a-methylene carbon shown in Fig. 22-(a). A, By and C represent the crystalline, crystalline-amorphous interfacial, and amorphous components, respectively...

In the hard kaolinites there is a positive correlation between mica and books which Hinckley suggests may be due, in part, to sedimentation conditions which favored the simultaneous deposition of books and mica in preference to quartz. This type also has Ti02 positively related to crystallinity. Crystallinity increases as grain size increases. This may reflect a leaching process in which quartz, Fe203 and montmorillonite are removed, Ti02 is concentrated as anatase, and some authigenic kaolinite is formed. 

Notes Sodium thiosulfate is one of a few known substances that will dissolve silver bromide. As such it is universally used in modern photographic procedures. In this process, which is known as fixation, the unexposed silver bromide is dissolved in the sodium thiosulfate by combining with it to form soluble complex thiosulfates of silver and sodium. Hypo is available in two forms anhydrous and, more commonly, crystalline. Crystalline hypo, when dissolved, lowers the temperature of the water considerably, whereas anhydrous does not. Always begin with water of at least 90F/32C when mixing the crystalline form. Use 64% of the anhydrous salt as a substitute for crystalline hypo. 

Four trimethyl-D-fructoses are known but only one of them is crystalline. Crystalline 1,3,4-trimethyl-D-fructose has been obtained from methylated levan,10 1,4,6-trimethyl-D-fructose from methylated melezi-tose and by synthesis, 3,4,6-trimethyl-D-fructose from methylated inulin and by synthesis, and 3,4,6-trimethyl-D-fructose has been synthesized. 

After filling of the DVB-DMN copolymer with methyl-containing silica, a band at 1144 cm1 was detected in the spectrum indicating increased crystallinity. Crystallinity was not detected in the spectrum of copolymer filled with methyl,hydride-containing silica. 

By contrast, the six monomeric 7-crystallin subunits do not have long flexible regions at their termini. Five 7-crystallin subunits have a relatively conserved hydrophobic two-residue extension at their C-terminus (Phe-Tyr in yB-crystallin) that is readily observed in the H NMR spectrum and is most likely involved in hydrophobic interactions with the other crystallin classes.63-64 The yS-crystallin subunit lacks these two C-terminal residues but instead has a four-residue flexible extension at its N-terminus that does not interact with the other crystallin classes to the extent of the C-terminal region in the other 7-crystallin subunits.63-64 As with the /3-crystallin subunits, the functional roles of the 7-crystallin subunits and their short extensions in crystallin-crystallin interactions are not fully understood. 

For a crystalline/crystalline blend, Yoshie et al. [151] studied blends of PVA and poly(3-hydroxybutyrate) (PHB). They found that PVA/PHB is compatible only when the blend contains a larger amount of PVA, and Model C was found with amorphous and crystalline PHB. Kwak et al. [94] studied poly(ether-ester)/PVC to find a common Ti, but double-exponential Tip decays. Model B was proposed with a mixed amorphous phase and two microcrystalline phases for component polymers. Note that Guo [95] reexamined this blend and pointed out that these assignments have to be reconsidered. 

Crystallinity. Most poly (thiol esters) are quite crystalline. Crystallinity can be lowered by using nonlinear monomers—for example, HSCH2(C2H5)CH-(CH2)4SH (31)—or by copolymerization (29). The x-ray pattern of a uniaxially oriented poly( -thiocaprolactone) (17) indicates that this polymer adopts a planar structure with extended chains. 

Crystalline-Crystalline Donor Acceptor Block Copolymers. 142... 

Scheme 2 Various donor and acceptor monomers can be combined to obtain block copolymers with amorphous or crystalline segments. In the left box, the polymerizable monomers are shown. On the right, the architectures of the resulting two main classes of D-A block copolymers are depicted amorphous-crystalline and crystalline-crystalline block copolymers...

However, another approach for improving the charge carrier mobility is to employ conjugated, semi-crystalline polymers. Here, a further advantage is the extended absorption in the visible range. These issues are addressed in the next chapter which is concerned with crystalline-crystalline block copolymers comprised of poly(3-hexythiophene) and PPerAcr. 

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