Anisotropic morphology

In order to study the connectivity of the anisotropic morphology, the 2D cuts of the 3D scalar field can be made at different angles to, for example, an XY plane. The 2D Euler characteristic can be calculated for each angle of the sectioning plan, and the anisotropic connectivity can be specified in this way. 

The authors ascribed the high WGS rates of the Pt/FSM-16 catalysts to confinement effects which increased the activities of Pt surface atoms, as well as to anisotropic morphological effects. Based on infrared studies, the authors identified unidentate formate species as intermediates in Au/NaY, and though the species was also observed on Au/Na Mordenite, the catalyst was found to deactivate by poisoning from a carbonate species. Only stable carbonates were observed on Au/Na-ZSM-5. The authors proposed a mechanism for Au/NaY, depicted in Scheme 94. 

Unfortunately, the X-ray diffraction patterns for different UZM-5 preparations showed broad peaks (due to the very small crystalhte size and anisotropic morphology) and were not of sufficient quality for ah initio structure solution. However, indexing the patterns did provide the crystal system (tetragonal) and approximate... 

Given the complex nature of the crystal structure and small crystal size with an anisotropic morphology of UZM-5, the normal X-ray diffraction patterns were not sufficient to deduce an unambiguous structure. Thus a multi-technique approach was required to successfully solve the structure, to explain the adsorption properties and by analogy to the structure of other zeolites in order to assess potential applications. 

A novel route for the synthesis of Si02 and Ti02 nanotubes with rectangular cross-section is developed. The high metal content and their anisotropic morphology render these tubelike nanocomposites attractive materials for nanoelectronics. In order to realize probable applications as nanowires, the synthesis route must be further optimized to obtain tubes, which are uniform in length and width. 

Liquid crystals combine properties of both liquids (fluidity) and crystals (long range order in one, two, or three dimensions). Examples of liquid crystalline templates formed by amphiphiles are lyotropic mesophases, block copolymer mesophases, and polyelectrolyte-suxfactant complexes. Their morphological complexity enables the template synthesis of particles as well as of bulk materials with isotropic or anisotropic morphologies, depending on whether the polymerization is performed in a continuous or a discontinuous phase. As the templating of thermotropic liquid crystals is already described in other reviews [47] the focus here is the template synthesis of organic materials in lyotropic mesophases. 

Theory. Basic theories for the prediction of the modulus of a composite from those of the components were derived by, for example, Hashin in 1955 (I), Kerner in 1956 (2), and van der Poel in 1958 (3). Takayanagi (4, 5), and Fujino et al. (6) developed a very promising and instructive model theory which includes calculation of the loss spectra of composites, and it may easily be extended to anisotropic morphologies. Furthermore, Nielsen and coworkers may be cited for fundamental theoretical and experimental contributions (7, 8, 9,10). 

Figure 11.7. Schematic iiiustration of (a) the anisotropic morphology of stretched SBS and (b) the periodic presence of disordered c/s-azobenzene and oriented trans-azobenzene in irradiated and nonirradiated fringes, respectively, for both perpendicular and parallel gratings recorded on azo-SCLCP-grafted SBS. Source Bai and Zhao, 2002. Reprinted with permission.

Anisotropic morphology has different effects on rheological properties compared to droplet morphology. When there is no interaction between the components in an immiscible multicomponent system, the rheological properties of a blend can be determined by a linear combination of each contribution ... 

Due to their anisotropic morphology with a unidirected pore structure on the micrometer level, biomorphous SiC- and SiSiC-ceramic composites represent interesting candidates for applications such as liquid metal filters, high-temperature catalyst supports or nozzle structures, and micro-reactor devices. 

The following section demonstrates the use of self-assembly as a nanofabrication tool in diverse examples of hybrid building blocks, mainly from our recent research. These involve different types of self-assembly aimed at the design of functional nanostructures at different length scales. The driving forces and functionality of these hybrid architectures are linked to the degree of anisotropic morphology, which reflects different levels of interaction and complex self-assembly. 

For pervaporation and gas sep ation, nonporous membranes are required preferably with an anisotropic morphology, an asymmetric structure with a dense top layer and an open porous sublayer, as found in asymmetric and composite membranes. The requirements for the substructure are in fact the same as for gas separation membranes ... 

Other applications in micro and nanoelectronics are been developed with the help of CNTs. One example is the development of sensors that are placed in situ in concrete for the evaluation of internal porosity [13], through the use of oriented nanotube membranes that vibrate when they are in the middle. For certain applications, the solution to this approach is the synthesis of films of aligned CNTs [14-17], enabling the manufacture of monitors and microwave generators. This is possible because of their ability to emit electron by field effect [18]. The applications of these films also include the development of polymeric solar cells the semiconducting properties of CNTs films with anisotropic morphology result in a route for the separation of pairs and conduction electrons/holes generated by photons [19]. 

There are different embodiments of SMSLS. They can contain flow cells, batch cells, or both. They can use lasers with beam splitters or individual lasers per cell. Cells can be in series, for applications where there is no tmbidity, in parallel when tmbidity is an issue, or some combination of the two. Other featmes are currently being added to SMSLS. Depolarized detection, for example, can monitor processes in which there are transitions from isotropic to anisotropic morphologies or vice versa, snch as nano- and micro-fibrillar modes of protein aggregation. 

An unusual feature of the work is the modeling of an isotropic (random) distribution of the montmorillonite within the polymer (continuous) matrix. The work above focused on modeling the composites with the montmorillonite aligned in the direction of the applied stress. This alignment is important for the full benefit of reinforcements of the anisotropic morphology of montmorillonite to be realized. This isotropic model predicts the modulus for epoxy and high viscosity polyester-montmorillonite composites well. 

The fourth significant independent variable that increases the thermal stability of polymer-clay nanocomposites is the barrier properties provided by the anisotropic morphology of the clay particles [3]. The mechanism of barrier performance of montmorillonite is fully developed... 

Isojima et al. also showed that by varying the ratio of metal nanoparticles to polymer matrix one can obtain both isotropic and anisotropic morphologies [84]. Another way of adding further or changing existing compartments is the removal of one compartment, for example by a selective solvent [85, 86]. 

Page KA et al (2006) SAXS analysis of the thermal relaxation of anisotropic morphologies in oriented Nafion membranes. Macromolecules 39(ll) 3939-3946... 

Figure 13.1 shows an atomic force microscopy (AFM) image of an AlN buffer layer, about 25-nm thick, grown in N-rich conditions (Al/N 0.7) on a (11-20) SiC oriented substrate. AFM reveals a highly anisotropic morphology, consisting of ripples oriented along the [1-100] direction. A sxuTace profile... 

The ordering field of LC molecules promotes the formation of LC polymer networks having anisotropic morphologies and the long range as the same length scale of LC textures... 

Figure 7.3 shows the complex nature of the concentration profiles in a columnar dendrite as determined by electron probe microanalysis. These clearly reflect the anisotropic morphology of the dendrite growth. The profiles agree with earlier results obtained using autoradiographyand with subsequent studies using a... 

The most common case for block copolymers forming anisotropic morphologies in thin films is for lamellae or cyfinders to orient parallel to the substrate. This is the case when the substrate tension or the surface tension against the different blocks is different. For the case of a AB diblotk copolymer, this is described by the cases yairCAj yaiiCB) and ) subsvate(A) ) substrate(B), where y represents the intetfadal tension. If each block shows equal interfadal interactions to the substrate and the surface, also known as neutral interphases, the domains will orient with the axes perpendicular to the substrate/surface. This is represented by yair(A) =yair(B) and... 

---