Carbon nanotubes functionalization additives

A limitation of AFM approaches in the study of porous materials is the limited ability of the scanned probe tip to penetrate and probe into smaller pores. This is illustrated in Chap. 2 (Fig. 2.23). Clearly, ultrasharp, high aspect ratio probe tips comprise an improvement in this respect. While carbon nanotube functionalized tips are not yet of widespread availability, conventional TM probes are preferred over CM probes because of the different opening angles (compare Chap. 2). In addition,... 

Rich A. Carbon nanotubes an additive with multi-functional properties and current commercial applications. Automotive Composites Conference and Exposition, conference proceedings. Society of Plastics Engineers 2006. 

Ghasemi I, Farsheh AT, Masoomi Z. Effects of multi-walled carbon nanotube functionalization on the morphological and mechanical properties of nanocomposite foams based on polyfvinyl chloride)/(wood flour)/(multi-walled carbon nanotubes). J Vinyl Addit Technol 2012 18 161-7. 

An additional and very attractive aspect of molecular qubits is the fact that they are stable in solution, and that the ligand shell can be functionalized with specific chemical groups. In recent years, this has enabled depositing molecular clusters onto different substrates and grafting them to nanostructures or devices, such as carbon nanotube single electron transistors or point contacts [112]. These devices... 

The following sections discuss many of the major particle types and provide bioconjugation options for the coupling of ligands to the surface of functionalized particles. Some additional nanoparticle constructs, including gold particles, dendrimers, carbon nanotubes, Buckyballs and fullerenes, and quantum dots are discussed more fully elsewhere (see Chapter 7 Chapter 9, Section 10 Chapter 15 and Chapter 24). 

In another example [56] SWNT was modified with peroxytrifluoroacetic add (PTFAA). Raman spectrum of the carbon nanotubes after the FIFA A treatment shows a D-line substantially increased indicating the formation of defect sites with sp3-hybridized carbon atoms on the sidewalls due to the addition of the functional groups. The RBM bands in the region of 170-270cm-1 decreased and shifted to higher... 

The diameter of the nanotube is an additional important parameter, with smaller tubes presenting enhanced curvature and consequently enhanced reactivity. One last aspect affecting reactivity is the helicity of the carbon nanotubes. In metallic CNTs, the aromaticity is slightly lower than in the semiconducting types, rendering the former more susceptible to functionalization. 

One problem associated with An + 2n cyclizations of carbon nanotubes is the reversibility of the process, and for this reason Diels-Alder reactions have been a less used synthetic route. One of the most representative examples of Diels Alder functionalization was reported by Langa and co-workers, who performed MW-assisted addition of o-quinodimethane on pentanol-ester functionalized SWCNTs [34]. 

Fig. 3.9 Functionalization of pristine carbon nanotubes by radical addition.

To summarize, one can say that the electrochemical performance of CNT electrodes is correlated to the DOS of the CNT electrode with energies close to the redox formal potential of the solution species. The electron transfer and adsorption reactivity of CNT electrodes is remarkably dependent on the density of edge sites/defects that are the more reactive sites for that process, increasing considerably the electron-transfer rate. Additionally, surface oxygen functionalities can exert a big influence on the electrode kinetics. However, not all redox systems respond in the same way to the surface characteristics or can have electrocatalytical activity. This is very dependent on their own redox mechanism. Moreover, the high surface area and the nanometer size are the key factors in the electrochemical performance of the carbon nanotubes. 

Acyl chloride-functionalized SWCNTs are also susceptible to reactions with other nucleophiles, e.g. alcohols. Haddorfs group reported the preparation of soluble ester-functionalized carbon nanotubes SWCNT-COO(CH2)17CH3 (Fig. 1.6a) obtained by esterification with octadecanol [134]. The syntheses of soluble polymer-bound and dendritic ester-functionalized SWCNTs have been reported by Riggs et al. by attaching poly(vinyl acetate-co-vinyl alcohol) (Fig. 1.6b) [135] and hydrophilic and lipophilic dendron-type benzyl alcohols [119], respectively, to SWCNT-COC1 (Fig. 1.6c). These functional groups could be removed under basic and acidic hydrolysis conditions and thus additional evidence for the nature of the attachment was provided [119, 136]. 

These examples of functionalization of carbon nanotubes demonstrate that the chemistry of this new class of molecules represents a promising field within nanochemistry. Functionalization provides for the potential for the manipulation of their unique properties, which can be tuned and coupled with those of other classes of materials. The surface chemistry of SWCNTs allows for dispersibility, purification, solubilization, biocompatibility and separation of these nanostructures. Additionally, derivatization allows for site-selective nanochemistry applications such as self-assembly, shows potential as catalytic supports, biological transport vesicles, demonstrates novel charge-transfer properties and allows the construction of functional nanoarchitectures, nanocomposites and nanocircuits. 

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