Hexagonally packed cylindrical

Light microscopy has been used in a number of contexts to characterize block copolymer morphology. For crystalline block copolymers, spherulitic structures that result from organization of crystalline lamellae can be examined using microscopy. In solutions, polarized light microscopy can reveal the presence of lamellar and hexagonal-packed cylindrical micellar phases. Cubic micellar phases are optically isotropic, and consequently cannot be distinguished from sols only on the basis of microscopy. 

The phase behaviour of blends of PS-PI or PS-PB diblocks with PS homopolymer was summarized by Winey et al. (19926). Regions of stability of lamellar, bicontinuous cubic, hexagonal-packed cylindrical and cubic-packed spherical structures were mapped out as a function of homopolymer molecular weight, copolymer composition and homopolymer concentration. All blends were... 

Based on the weight loss during the PEC process measured using the microbalance, the porosity is estimated to be 0.1. Because the columnar pores are generally uniform throughout the porous layer, it is reasonable to assume that the columnar porous structure we obtain is comparable with a perfect hexagonal packed cylindrical pore lattice. For such a pore lattice, the porosity P can be calculated using ... 

An isothermal morphology diagram of poly(styrene-fe/oc -butadiene) is shown in Fig. 19 as a function of molecular weight and copolymer composition the classic morphologies include spherical microdomains (0< a<0.15) packed in a body-centered cubic lattice, hexagonally packed cylindrical microdomains (0.15 <( a-0-3), and alternating lamellae of approximately symmetric diblocks (0.3 <0 -0-5). Sever-... 

The pore size and the pore wall thickness of mesoporous silica obtained using C8Fi7S02[C3H7]N(EO)ioH surfactant are shown in Table 11.2. These results are compared to the typical values described for MCM-41 and SBA-15 sUicas, which have a similar mesostructure consisting of hexagonally packed cylindrical mesopores. 

Figure 6-11. T smisston electron micrographs of gold partide preparation in hexagonal packed cylindrical microdomains of phase separated norbornenyl phosphine/gold complex copolymCTs a) before and b) after gold particle formation. (Bar = 100 nm in a) 50 nm in b) reproduced by permission from ref. [155J.)...

Several ordered states distinguished by their symmetries have been identified the preferred one depends primarily on the polymer composition [29,38,39]. Some common patterns are lamellar sheets, ordered bicontinuous double diamond (OBDD), hexagonally packed cylindrical arrays, and body-centered-cubic spherical microstructures. If the volume fractions of the two halves of the polymer chain are similar, the interface between the two regions will be flat and the lamellar phase will form. However, if one block is much smaller than the other, then for packing reasons, the interface will curve toward the smaller half (see Fig. 19b), giving, in order of increasing curvature, the OBDD, cylindrical, and spherical microstructure. 

Fig. 8.1 Schematics of various micelles formed at various surfactant concentrations above the CMC (a) Spherical micelle forms first as the concentration of surfactants is above the CMC (b) Individual cylindrical micelle forms at the concentration of surfactants increases further (c) Further increased concentration of surfactants results in the formation of hexagonally packed cylindrical micelles (d) Lamellar micelles would form when the concentration of surfactants...

Figure 5.5 TEM bright-field images of the self-assembled microstructures of poly[(NBE)-6/oc/c-(NBE decaborane)] after solvent evaporation. (a) TEM showing the end view of a hexagonally packed cylindrical structure obtained using THE as the solvent.

Hashimoto, T., Kawamura, T, Harada, M., and Tanaka, H. (1994) Small-angle scattering from hexagonally packed cylindrical particles with paracrystalline distention. Macromolecules, 27,3063-3072. 

Figure 9 Polystyrene-block-polybutadiene-block-poly(methyl methacrylate) S-B-M with a B matrix embedding hexagonally packed cylindrical domains of S and M. (a) Transmission electron micrograph stained with OSO4 (b) Scheme of the morphology. (From Ref. 186, Copyright 1998 American Chemical Society.)...

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