Crystalline core

Fig. 2.1. The crystalline model a single crystal in which molecules traverse the lamella perpendicular to the fold surface. Cilia are formed at the end of the molecules outside the crystalline core. The folds are predominantly adjacent and the loop sizes may vary...

Block copolymer micelles in which the core-forming polymer blocks are able to crystallize are relatively similar to rod-coil copolymers. A significant part of these crystalline-core micelles is actually resulting from the self-assembly of rod-coil block copolymers. 

Figure 1.1. Electron micrographs of leukocytes (a) neutrophil, showing polymorphic nucleus and numerous cytoplasmic granules (b) eosinophil, showing distinctive granules with crystalline core (c) monocyte, with horseshoe-shaped nucleus (d) small lymphocyte. Magnification x7000.

Figure 6.5 Illustrations of nanoscale spherical assemblies resulting from block copolymer phase separation in solution are shown, along with the chemical compositions that have been employed to generate each of the nanostructures (a) core crosslinked polymer micelles (b) shell crosslinked polymer micelles (SCKs) with glassy cores (c) SCKs with fluid cores (d) SCKs with crystalline cores (e) nanocages, produced from removal of the core of SCKs (f) SCKs with the crosslinked shell shielded from solution by an additional layer of surface-attached linear polymer chains (g) crosslinked vesicles (h) shaved hollow nanospheres produced from cleavage of the internally and externally attached linear polymer chains from the structure of (g)...

The crystalline core can make SiNW either fairly straight, or coiled or curly. It was discovered that CH4 may affect the helicity. This may be caused by a more complicated phase diagram that involves carbon, silicon, and metal. 

Figure 65. High-resolution transmission electron micrograph of a single Cr02 particle showing the topotactically grown crystalline core-shell structure...

Nanoparticles can be separated by molecular exclusion chromatography just as proteins are separated. Figure 26-15 shows the relation between measured size and retention time of CdSe quantum dots. These are particles containing 2 000 CdSe units in a dense, crystalline core capped by alkyl thiol (RS) groups on Cd and trialkylphosphine (R3P) groups on Se. 

The second point concerns the surface mobility of atoms on small particles at low temperatures (close to ambient). From the work of Listvan106 on Au clusters it appears that surface mobility of Au occurs at room temperature (see also refs. 102 and 107). In this work it is proposed that a small particle consists of a crystalline core covered with a few disordered layers of mobile surface atoms. If such mobility is real it raises important questions about the relevance of bulk structures to surface structures in small particles. LEED experiments clearly show108 109 that for a bulk solid such a surface film does not exist at, or near, room temperature. However, the situation for small particles is less clear, and several theoretical treatments109 110 have emphasized that the solid-liquid transition should always appear smeared out when the particle size decreases. Catalysis depends on surface effects, so may be less dependent on particle size or overall morphology than might be anticipated. 

Fig. 6 a TEM images of the CNT-g-P2VP after deposition of PB2 clusters. b,c HR TEM images of the core-shell structure of the particles consisting of a dense crystalline core (diameter of 3-5 nm) surrounded by a few nanometer-thick amorphous shell. HR TEM image (d) and selected area diffraction pattern (e) confirm the crystalline structure of the PB clusters (lattice distances of 2.09 A (Fe —N), 1.96 A and 1.83 A (Fe —C) that correspond to the (422), (333) and (404) reflections, respectively)... 

Reconstitution experiments with apoferritins from animal and bacterial sources, whose native iron-loaded ferritins had crystalline and amorphous cores respectively, have been informative in showing that the core morphology is not determined by the protein shell. For example, Baaghil et al and Mann etalP were able to form crystalline cores in bacterioferritins, and Rohrer formed cores of iron-... 

These are experimentally determined values for polydisperse preparations of the holoferritins. a, Amorphous core c, crystalline core Ic, core of limited crystallinity. 

Figure 5.13. Schematic model showing the hard PBT particles (crystalline cores and surface amorphous regions) embedded in the amorphous phase of the soft segments. (From Balta Calleja etai, 1998.)...

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