Morphology of Materials

The magnetic, optical, and electrical properties of materials often depend on the microstructural details and the morphology of materials. Even if the final state is not a colloid, many products pass through colloidal processing routes prior to the final stage. The availability of methods to produce model particles allows us to study and control the desired properties of the final product. 

In Figure 4.11, the interaction of a high-energy electron beam with materials is represented. The electrons hitting the material surface provoke the emission of electrons from the specimen mainly as backscattered electrons (BSEs) and SEs. SEs are ordinary signals used for the study of the surface morphology of materials. SEs have low kinetic energy, that is, lower than 50 eV. 

In Chapter 2, we have studied the structure and the morphology of materials, and in Chapter 3 some of the methods of materials syntheses were studied. Among the materials included were some of the catalysts and supports, which are described here. These chapters should be referred to for the structure and syntheses methods, and this chapter focuses on catalysts and the modification of materials to obtain catalysts. 

Membrane autopsy and subsequent tests are generally the last resort in determining a definitive cause for membrane failure. This is because these tests are all destructive to the membrane module and membrane itself. The tests are used to determine the morphology of material on the membrane, the types of chemicals present, the amount of a specific species found on the membrane, and the nature of the materials that oxidized the membrane.7... 

Scanning electron microscopy (SEM), along with stereo or standard light microscopes, can be used to determine the morphology of materials on the surface of a membrane. 

Zhang, Y. L., R. W. Blanchar, and R. D. Hammer. 1993. Composition and pyrite morphology of materials separated from coal. In Proceeding of 10th National Meeting of American Society of Surface Mining and Reclamation, Vol. 2. Spokane, WA, May 16-19,1993. pp. 284-297. 

Several research approaches are pursued in the quest for more efficient and active photocatalysts for water splitting (i) to find new single-phase materials, (ii) to tune the band-gap energy of TJV-active photocatalysts (band-gap engineering), and (iii) to modify the surface of photocatalysts by deposition of cocatalysts to reduce the activation energy for gas evolution. Obviously, the previous strategies must be combined with the control of the s)mthesis of materials to customize the crystallinity, electronic structure, and morphology of materials at nanometric scale, as these properties have a major impact on photoactivity. 

Transmission electron microscopy (TEM) is also used to visualize materials using electrons. Samples must be thin enough that the electrons transmit through them and then onto a detector below the sample. TEM can be used to look at the morphology of materials and also probe the crystalline properties. When crystals are present the electrons are diffracted, similar to what occurs with XRD. The diffracted electrons provide a picture with lines crisscrossing each other, and the lines represent the crystal lattice. 

In order to determine the microscopic morphology of materials, scanning probe microscopies are particularly interesting since they allow the visualization of nanoscale objects in direct space. This family of techniques is complementary to electron microscopies (because the measurements can be carried out on as-prepared samples, without special conditioning) and to scattering experiments (because they... 

Most surfaces are fractal and their chemistry differs from that of flat crystal faces. The chapters comprising this volume are concerned with the chemistry of molecules, solids, surfaces, and fractal matter. Not only the morphology of materials controls many of their properties but the fractal dimension of the matter distribution in materials also strongly affects the result of chemical processes in or on those distributions of atoms. Dimensions of interfaces pervade materials properties and it is difficult to ignore them when optimizing polycrystalline composites. 

SME results from a combination of the polymer architecture/morphology and the applied SMCP (see Sect. 1). The morphology of materials describes its structural form, i.e., the size, shape and texture of domains formed by chain segments [32], The molecular structure and the morphology of SMPs can be observed by several well-established classical polymer characterization methods at various length scales from the molecular to the macrolevel. 

For ESs, FTIR is usually used with TEM, SEM, XRD, BET and other techniques to characterize electrode materials. For example, FTIR is used to examine and chemically confirm the presence of uniform ultrathin polymer layers formed on carbon nanofiber electrodes [52]. FTIR, SEM, and XRD are also used to study surface morphologies of materials, for example, surface changes created during activation of polyacrylonitrile thin films deposited on carbon fibers. Other examples include analysis of CNT electrodes after polyaniline... 

Under this backdrop, we have decided to produce an article that is designed to be helpful to students and postdocs who are entering this field. Rather than focusing on the efficiency of devices or the morphology of materials (subjects that are covered very well elsewhere), we instead focus some attention on how to approach OPV research from a more practical (laboratory-based) perspective. Section 1 introduces... 

Conner and coworkers (refs. 7,8) have recently utilized a pore/throat network model to obtain information about the morphology of materials from mercury penetration data. The void/solid structure is viewed as an interconnected network so that adsorption/desorption and retraction/intrusion can be associated with the openings and constrictions within the void network. These latter investigators analyzed the data as if the materials consisted of agglomerated microspheres. The measured ratio of the most probable radii of intrusion to those of retraction seemed to be characteristic of the void structure and pore shape. Conner et al. (ref. 8) developed a heuristic diagram for the classification of void/solid morphologies from a... 

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