Mesoscale structure

The use of DNA as a template to fabricate mesoscale structures was also demonstrated in a recent work of Torimoto and coworkers. They used preformed, positively charged 3-nm CdS nanoparticles with a thiocholine-modified surface to be assembled into chains by using the electrostatic interaction between positively charged nanoparticle snr-faces and the phosphate groups of DNA. As determined by TEM analysis, the CdS nanoparticles were arranged in a qnasi-one-dimensional dense packing. This revealed interparticle distances of about 3.5 nm, which is almost equal to the height of one helical tnm of the DNA double strand [98]. 

Block copolymer phase separation has first and foremost been studied in bulk. The mesoscale structure is determined by molecular parameters such as chain length (N), volume fractions of the components, interaction between the blocks (x) and temperature (Figure 2.6). In this Chapter, we will be concerned mainly with diblock copolymers,... 

Gwo, J.P., R, O Brien, and P.M. Jardine. 1998. Mass transfer in stmctured porous media Embedding mesoscale structure and microscale hydrodynamics in a two-region model. J. Hydrol. 208 204-222. 

Fig. 4.3 AVHRR 1-km SST image for 24 July 2000 showing mesoscale structure in the Eastern Mediterranean. Raw data obtained from the NOAA Satellite Active Archive and processed at Plymouth Marine Laboratory.

The linear viscoelastic properties in the melt state of highly grafted polymers on spherical silica nanoparticles are probed using linear dynamic oscillatory measurements and linear stress relaxation measurements. While the pure silica tethered polymer nanocomposite exhibits solid-like response, the addition of a matched molecular weight free matrix homopolymer chains to this hybrid material, initially lowers the modulus and later changes the viscoelastic response to that of a liquid. These results are consistent with the breakdown of the ordered mesoscale structure, characteristic of the pure hybrid and the high hybrid concentration blends, by the addition of homopolymers with matched molecular weights. 

Figure C2.3.5. Mesoscale structures deriving from surfactants nominally exhibiting shapes corresponding to various packing parameter ranges.

The formation of surfaee aggregates of surfaetants and adsorbed micelles is a challenging area of experimental research. A relatively recent summary has been edited by Sharma [51], The details of how surfactants pack when aggregated on surfaces, with respect to the atomic level and with respect to mesoscale structure (geometry, shape etc ), are less well understood than for micelles free in solution. Various models have been considered for surface surfactant aggregates, but most of these models have been adopted without firm experimental support. 

R 125 P. Stilbs, Characterization Mesoscale Structure and Phenomena in Fluids Using NMR , p. 27 Vol. 864, 2004 Hemicelluloses... 

Stilbs" discussed NMR techniques that provide valuable insight into the structure and dynamics of mesoscale structures. In particular spin relaxation effects were considered. Klein and Ries reviewed the importance of NMR for studying glasses. 

C.H. Tan, A.R. Inigo, J.H. Hsu, W. Fann, and P.K. Wei, Mesoscale structures in luminescent conjugated polymer thin films studied by near-field scanning optical microscopy. J. Phys. Chem. Solids, 62, 1643 (2001). 

DNA is used as a stabilizer/template in the formation of CdS nanoparticles and its mesoscopic aggregates. Use of linear duplexes of DNA in solution help in this formation. In the beginning it was inferred that in DNA CdS nanoparticles split to form Cd and S . The role of DNA-nanoparticle interaction was unclear. When studied further it was realized that the DNA base sequence had a significant effect on the size of the CdS particles and their photophysical properties. DNA sequence in general and base adenine in particular had its influence on CdS particles. Coffer and co-workers 1996 developed a technique to synthesize well-defined mesoscale stractures in solution by binding a template DNA strand to a solid substrate. By controlling the particle composition, shape, length, and sequence of the DNA template via this approach a number of mesoscale structures were obtained. 

Rathgeber S, Perlich J, KAhnlenz F, TArk S, Egbe DA, Hoppe H, et al. Correlation between polymer architecture, mesoscale structure and photovoltaic performance in side-chain-modified poly(p-arylene-ethynyl-ene)-alt-poly(p-arylene-vinylene) PCBM bulk-heterojunction solar cells. Polymer 2011 52(17) 3819-26. 

The SEM pictures fi om Figure 9.12A-D show the nano- to mesoscale structure of the aerogel filaments. In Figure 9.12A, a part of a fiber s surface is flaked off. The fibers exhibit the typical mantle-core stracture and are well known from cellulose fiber production [31],... 

Figure 9 Dendrimers and dendrons are unique building blocks from supramolecular nanoscience—the molecular architecture can control the mode of self-assembly as illustrated in this figure, showing the hierarchical self-assembly of different dendrons into nano and mesoscale structures. (Reproduced from Ref. 64. American Chemical Society, 2009.)...

Most adaptronic structures are used, or are intended to be used in macroscopic devices. In a single domain crystal system, macroscopic properties are simply the statistical average of microscopic properties of each miit cell. For most functional materials, however, such a simple average fails due to nonlocal interactions and the additional mesoscopic structures created at the intermediate length scale, such as domain patterns in single crystal systems and grain microstructures in ceramics. These nonlocal interactions and mesoscale structures often produce very strong extra enhancement to the functional proper-... 

Working on these systems showed that the performance of such materials may suffer from their low electronic conductivity of active components and the large volume changes in the electrodes. In this context, metal nano/mesoscale structures gained considerable attention because of their novel physical and chemical properties that are not present in their corresponding macroscale structures. The mesoscale structure of the battery material seems to be vital to further improvement of the electrochemical performance and first promising results will be presented for both the negative and the positive electrode of this type of batteries. The chapter will also provide examples for anode and cathode systems which are based on the conversion principle and on the use of nanoscale... 

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