Nanotechnology template synthesis

Co-axial electrospinning has also been used to develop hollow nanofibers or nanotubes from ceramic and ceramic-polymer composites that are otherwise commonly prepared using tedious processes, such as self-assembly and template synthesis. The latter are known as bottom-up techniques in nanotechnology,as they require atoms and molecules to be manipulated and assembled in desirable structures that are at least an order of magnitude larger than the molecules themselves. The procedure for making hollow fibers at nano level is, in fact, opposite to that illustrated in Fig. 2.33. In the current case (Fig. 2.34), the core, instead of the sheath, is selectively removed. 

Liang M, Wang L, Liu X, Q1W, Su R, Huang R, Yu Y, He Z (2013). Cross-linked lysozyme crystal template synthesis of Au nanoparticles as high-performance req clable catalysts. Nanotechnology, 24,245601. 

Since the disclosure by Mobil of Micelle-Templated Silicate structures called MCM-41 (hexagonal symmetry) or MCM-48 (cubic symmetry) [1,2] many other structures have been synthesized using different surfactants and different synthesis conditions. All of these Micelle-Templated Silicas (MTS) have attracted much interest in fields as diverse as catalysis, adsorption, waste treatment and nanotechnology. MTS materials possess a high surface area ( 1000 m2/g), high pore volume ( 1 mL/g), tunable pore size (18-150 A), narrow pore size distribution, adjustable wall thickness (5-20 A). The silica walls can be doped with different metals for catalytic applications, like Al orTi, for acidic or oxydation reactions, respectively. 

All sorts of everyday objects have been reconstructed as molecules via template-directed synthesis of mechanical bonds, from switches and buttons to rotors and elevators. The likeness of MIMs to macroscopic objects and machines has done much to advance molecular nanotechnology and is, as we shall see, another important aspect of their beauty. 

PANI nanowires are ID nanostructures which are very interesting from the nanotechnology point of view, due to their potential use in sensors and nanoscale electronic devices. DNA can be considered as an anionic polyelectrolyte that can behave as a template for PANI enzymatic polymerization in solution [20]. Double stranded DNA can be attached to aminated surfaces by electrostatic self assembly, providing a linear template for further aniline electrostatic assembly. By using this method followed by enzymatic polymerization of the assembled aniline, Ma et al. [69] and Nickels et al. [70] showed that stretched DNA molecules were able to template the enzymatic synthesis of PANI nanowires, according to the mechanism showed in Figure 8.7. 

Study of nanoscale biological systems and phenomena, the use of biological components in nanotechnological applications and the synthesis or construction of nanometre scale mimics of biological entities. Examples include the use of DNA for molecular computing, or as a nanoscale structural scaffold, and the temptation of nanostructures using bacterial S-layers (Section 14.6.2). With these ideas in mind we turn first to templated morphosynthesis the chemical synthesis of nanoscale morphologies that often mimic complex structures found in the Natural world. 

Sarkar D., Mandal K. and Mandal M. (2011). Synthesis of Chainlike alpha-Fe203 Nanoparticles in DNA Template and Their Characterization. Nanoscience and Nanotechnology Letters, 3(2), 170-174. 

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