Nanostructures hierarchy

There is a wide range of so-called bottom-up methods for achieving complex structural hierarchies within polyfluorene nanostructures. Synthesis of block... 

Fig. 7 Nanostructured microporous nickel with accessible pores showing the hierarchy of the pore sizes (A) micropores created by fused metal grains (B) structure of the metal grains before heat treatment (C) surface pore structure of the grains and (D) inner structure of metal grains showing the existence of a porous inner core.

Figure 7.17 SEM images of nanocomposites with hierarchial nanostructures prepared by electrospinning followed by calcination (a) V20s-Ta205 nanorods on Ti02 nanofibers, and (b) V2O5 nanorods on Si02 nanofibers. (Reprinted with permission from R. Ostermann et al. Nano Lett. 2006, 6, 1297. Copyright (2006) American Chemical Society.)...

Incorporation of structural hierarchy enhances the superhydrophobicity further. Jxmg et at have compared the nanostructured and hierarchical surfaces of CNTs [221]. The hierarchal structure is formed by applying CNT on microstructures Si replica. With a contact angle of 170°, the hierarchical structured surfaces exhibit higher superhydrophobic nature as compared to that of nanostructured surface (contact angle 166°). 

D, and 3-D systems are shown in Figure 17.1, as a nanowire, a thin film, and a nanoporous/nanograinedbulk material, respectively. In practice, nanostructured ceramic materials often contain a hierarchy of 1-D, 2-D, and 3-D structures, as illustrated later in the chapter. 

FIGURE 1.1 The concept of nanoarchitectonics a new methodology to produce architectures organized on multiple length scales, which bear a closer resemblance to the human body made up of hierarchies of nanostructures of biological molecules, cells, and tissue. 

In this chapter, we have provided an overview of die theoretical understanding of CCL operation at a hierarchy of scales. The long-term objective, facilitated by this systematic understanding, will be to develop nanostructured architectures for catalyst layers with high activity, low catalyst loading, and high stability. 

The variety of the nanostructures could become even richer and more complex in multiblock copolymers, multiblock multicomponent (e.g. terpolymers) or in nonlinear (e.g. miktoarm stars) (Lodge, 2003) chimeras, approaching that found in nature. Therefore, the synthesis of well defined complex chimeras adds another dimension to the suprastructural hierarchy of the block copolymers with potential biomedical applications (Deming, 2007). 

Apart from the hierarchy of bone structures discussed in the last section, bone chemical composition is another important aspect. Bone in nature is a nanostructured composite with an organic matrix and an inorganic reinforcing phase (Liu and Webster, 2007a). Bone chemical composition varies with many factors, such as age and individual health status. Calcified bone is composed of 25% organic matter and 75% inorganic matter (70% minerals and 5% water) by weight (Sommerfeldt and Rubin, 2001). 

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