Nanometer-size materials

Hence polysaccharides have been viewed as a potential renewable source of nanosized reinforcement. Being naturally found in a semicrystalline state, aqueous acids can be employed to hydrolyze the amorphous sections of the polymer. As a result the crystalline sections of these polysaccharides are released, resulting in individual monocrystalline nanoparticles [13]. The concept of reinforced polymer materials with polysaccharide nanofillers has known rapid advances leading to development of a new class of materials called Bionanocomposites, which successfully integrates the two concepts of biocomposites and nanometer sized materials. The first part of the chapter deals with the synthesis of polysaccharide nanoparticles and their performance as reinforcing agents in bionanocomposites. 

On the other hand, the nonlinear optical properties of nanometer-sized materials are also known to be different from the bulk, and such properties are strongly dependent on size and shape [11]. In 1992, Wang and Herron reported that the third-order nonlinear susceptibility, of silicon nanocrystals increased with decreasing size [12]. In contrast to silicon nanocrystals, of CdS nanocrystals decreased with decreasing size [ 13 ]. These results stimulated the investigation of the nonlinear optical properties of other semiconductor QDs. For the CdTe QDs that we are concentrating on, there have been few studies of nonresonant third-order nonlinear parameters. 

M. Kang, The superhydrophilicity of Al-Ti02 nanometer sized material synthesized using a solvothermal method , Materials letters, 59, 3122-3127, (2005). 

Nanometer-size materials have attracted remarkable academic and industrial research interest due to their fundamental properties and their potential apphca-tion, ranging from fundamental studies to catalysis [125-130]. Precise control of size and chemical behavior (stability and reactivity) by means of the synthesis itself is a major aim due to the direct correlation of intriguing new properties with particle size, bridging the gap between molecules and bulk materials. 

Moreover, we have demonstrated that the size of the active material grains is of great importance for the understanding of the interfacial behavior, because of the larger specific surface area exhibited by the nanometer-sized materials. 

One-dimensional nanometer-sized materials (e.g., thin films)... 

A polymer nanocomposite is a multiphase material in which a polymer matrix is combined with nanometer-sized materials having one, two, or three dimensions smaller than 100 nm, or structures having nanoscale repeat distances between the different phases that make up the bulk polymer material (Thostenson et al. 2005 Lin et al. 2011a, b). In a polymer nanocomposite, the polymer matrix functions as a concentrated component that enables a phase continuum, while nanomaterials are deliberately added to induce an enhanced performance in the functional properties such as mechanical, barrier, electrical, triggered biodegradabilily, moisture resistance, and thermal properties of the polymer (Thakur et al. 2012, 2014c, d, e). 

Classical simulations often lack the crucial insight into the problem, because one cannot simply use the force to characterize all the possible interactions. Fortunately, with decades of development, theoretical calculations have become quite sophisticated for crystals and molecules, although not yet for realistic nanometer-sized materials. For solids, the pseudopotential as well as the full-potential linearized augmented plane-wave (FLAPW) method within the density functional theory are well developed. Modern quantum chemical techniques (Gaussian98 [5] and MOLPRO [6]) are quite efficient to compute the potential surfaces for a given molecule. In order to illustrate those possibilities, we show some of our own results in simulating the reaction path for a segment of the retinal molecule in rhodopsin [7]. 

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