Surface-to-bulk ratio

Increasing the surface-to-bulk ratio of the sample to be studied. This is easily done in the case of highly porous materials, and has been exploited for the characterization of supported catalysts, zeolites, sol-gels and porous silicon, to mention a few. 

By using dispersed samples, the surface-to-bulk ratio is increased, and standard methods of studying bulk samples will work (see the article on EXAFS). 

For poorly soluble drugs, the digestive absorption depends on their rate of dissolution. Decreasing the particle size of these drugs to increase the surface-to-bulk ratio improves their rate of dissolution. Fine-grinding mills are used to... 

The high surface-to-bulk ratio in nanostructures means that a nanocrystal structure is determined by a balance between bulk terms such as lattice energy, surface energy terms, and terms due to faults (such as dislocations) as all these terms are now significant. This can lead to unusual crystal structures such as thin films of bcc copper, compared with the normal bulk structure which is ccp. 

Although nanoscale materials promise to revolutionize many of our industries including electronics, health care, energy and more, the near term uses are in environmental remediation and green chemistry applications. One reason for this is that nanomaterials possess unique properties as adsorbents and catalysts, because (1) they possess high surface areas with large surface to bulk ratios so that the nanomaterial is used efficiently (2) nanocrystals have... 

The measured data give evidence that the susceptibility of palladium deposited on silica gel surfaces is dependent on both the surface to bulk ratio and the lattice constant. They also show definite surface states on the palladium crystallites with more holes in the d-band of the surface than in the rest of the metal. 

Nanoparticle materials are important because they exhibit unique properties due to size effects, quantum tunneling, and quantum confinement. As sizes of embedded particles are reduced to the nanometer scale, the surface-to-bulk ratio increases significantly. Therefore, surface effects can dominate bulk properties and an understanding of nanosurfaces becomes important. In this chapter, we discuss characterization of vacancy clusters that reside on surfaces of embedded nanoparticles as well as studies on the correlation of surface vacancy clusters to the properties of the nanomaterials. 

Due to its high surface area, surface chemistry and physics dominate the properties of fumed silica. The O—Si-O being 0.3 to 0.4 nm let estimate about only 20 silicon dioxide units spanning the diameter of a primary particle of amorphous silica. Fumed silica therefore has an extremely high surface to bulk ratio up to about 10 %. This is why even bulk methods of chemical analysis are suitable to follow chemical reactions on its surface elemental analysis, IR or NMR methods, etc. 

CNTs have been touted as next-generation sensing agents in conventional gas sensors due to their high surface-to-bulk ratio, but their ability to produce high... 

Neutron scattering is known to be a very valuable tool for studying the dynamics of bulk hydrogen. Ihcreased neutron flux (lO - 10 neutrons/ cm sec) allows the investigation of the dynamics of adsorbed hydrogen for samples with a reasonably high surface to bulk ratio. The sample can be... 

As the cluster size increases, the cluster properties evolve toward their bulk coimterparts. The understanding of this evolution is of fundamental importance not only from the perspective of basic science but also from the technological viewpoint. At a very approximate level, one can claim that the cluster properties can be described in terms of their surface and core (bulk) contributions and due to the fact that the surface to bulk ratio gets smaller as the cluster size increases. Consequently, it is natural to expect that the cluster properties will evolve to their corresponding bulk-phase ones for large cluster sizes. 

As described in the Sect. 3.3, transition metals are conjugated with n-conjugated polymer like polyanilines. The transition metals can be extended to the transition metal nanoparticles (NPs). The resulting hybrids of metal NPs and polyanilines are expected to be of their potential applicability as electronic devices, chemical sensors, and catalysts. The NPs with small size and high surface-to-bulk ratio exhibit advantages compared with the bulk materials in the catalytic applications [73]. Therefore, the smaller and well-dispersed NPs are desired. 

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