Templating, direct, nanostructure

Template-Based Synthesis Template directed synthesis represents a convenient and versatile method for generating ID nanostructures. In this technique, the... 

The chemical methods for the preparation of nanomaterial could be categorized as either template-directed or template-free. The template synthesis methods commonly used for the production of one-dimensional nanostructured PANI are further subdivided into hard template (physical template) synthesis and soft template (chemical template) synthesis approach according to the solubility of the templates in the reaction media. Non-template routes for the synthesis of one-dimensional nanostructured PANI such as rapid-mixing reaction method, radiolytic synthesis, interfacial polymerization, and sonochemical synthesis have also been reported [56], Other approaches like combined soft and hard template synthesis are also known. An overview of hard-template, soft-template, and template-free procedures are presented in the following paragraphs. 

Template-directed generation of nanostructures in polymers thus indeed leads to antibody-like interaction abilities and thus highly appreciable selec-tivities. Sensitivity is added to the systems mainly by the transducer device, where the mass-sensitive strategy offers the big advantage of detecting a property that is inherent for any analyte. On a laboratory scale, sensor systems for a variety of analytes ranging from small molecules (volatile organic compounds) up to entire cells have been proposed. 

Electrochemical polymerization provides a convenient approach to fabricate CNTs/CP nanocomposites [46-53], Using such a strategy, the morphology and properties of the nanocomposites can be controlled by the electropolymerization conditions, such as the applied potential or current density. Ajayan and co-workers have reported the electrochemical oxidation of aniline in H SO on the CNTs electrode to fabricate CNT/PANl composites [46]. Chen et al. fabricated CNT/PPy nanocomposites, the first example of anionic CNTs acting as the dopant of a CP [47]. Their results showed that PPy was xmiformly coated on the surface of individual CNTs by electrolysis at a low apphed potential for a short time, rendering them potential applications in nanoelectronic devices. Another kind of CNTs/CP composite nanostructures, e.g., CNTs as inorganic fillers in CP matrices [54] can be prepared by a template-directed electropolymerization method. (Figure 13.3)... 

Figure 21 Left AFM height image and cross-sectional analysis of molecular brushes with PnBA-b-PAN-b-PfBA triblock terpolymer side chains. Right Synthetic scheme of template-directed synthesis of carbon nanostructures from core-shell-corona structured PnBA-b-PAN-b-PAA molecular brushes. Reprinted from Tang, C. Dufour, B. Kowalewski, T. Matyjaszewski, K. Macromolecules 2007, 40 (17), 6199-6205, with permission from ACS. ...

This section has discussed a diverse range of self-assembled synthetic macromolecules such as block copolymers and elastm-like polymers for template-directed assembly of different types of inorganic nanoparticles into anisotropic ID nanostructures. In the next section, we introduce a simple and cost-effective approach for directing the assembly of gold nanoparticles into ID structures via self-assembly of a short commercially available surfactant. 

A quite widely used method for the achievement of nanostructured polymers deals with the assistance of templates. Direct templating is particularly suited for getting mesostructures of organic and soft materials such as polymers that, in general, can be easily replicated by adopting hard templates which allow a great synthetic flexibility. 

A second method for the formation of nanostructured surfiice-functionalized ionosilicas consists in the cocondensation reaction involving ionic precursor displaying surfactant-like behavior (Scheme 16.8) [108]. Template-directed syntheses of long chain-substituted silylated imidazolium or ammoniiun precursors in the presence of cationic surfactant such as CTAB or cetylpyridinium chloride yield highly structured ionosilica materials with surface-tethered ionic groups. 

Template-Directed Controlled Electrodeposition of Nanostructure and Composition... 

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