Carbon nanotubes surface functionalization

Peng S, Cho K (2003) Ab initio study of doped carbon nanotube sensors. Nano Lett 3(4) 513—517 Penza M, Cassano G, Rossi R, Alvisi M, Rizzo A, Signore MA, Dikonimos T, Serra E, Gioigj R (2007) Enhancement of sensitivity in gas chemiresistors based on carbon nanotube surface functionalized with noble metal (Au, Pt) nanoclusters. Appl Phys Lett 90 173123... 

Chahine, N.O., et al., 2014. Nanocomposite scaffold for chondrocyte growth and cartilage tissue engineering effects of carbon nanotube surface functionalization. Tissue Engineering. Part A 20 (17-18), 2305-2315. Available at http //www.ncbi.nbn.nih.gov/pubmed/24593020 (accessed 08.10.14.). 

I. Gerber, M. Oubenali, R. Bacsa, J. Durand, A. Gonsalves, M. F. R. Pereira, F. Jolibois, L. Perrin, R. Poteau, P. Serp, Theoretical and experimental studies on the carbon-nanotube surface oxidation by nitric acid Interplay between functionalization and vacancy enlargement, Chem. Eur. J., vol. 17, pp. 11467-11477, 2011. 

Peng, X. and S.S. Wong, Functional covalent chemistry of carbon nanotube surfaces. Advanced Materials, 2009. 21(6) p. 625-642. 

Dameron, A.A., et ah, Aligned carbon nanotube array functionalization for enhanced atomic layer deposition of platinum electrocatalysts. Applied Surface Science, 2012. 258(13) ... 

Chen J, Liu H, Weiner W A, Halls M D, Waldeck D H and Walker G C (2002) Noncovalent engineering of carbon nanotube surfaces by rigid, functional conjugated poljuners, J Am Chem Soc 124 9034-9035. 

Wang and colleagues studied file functionalization of composite nanofibers of poly(acrylonitrile-co-acrylic acid) [P(AN-AA)] and multiwalled carbon nanotubes (MWCNTs) by attaching catalase (hydrogen peroxide oxido-reductase from bovine liver) onto the carbon nanotube surface. The activity of the catalase was reported to increase by about 42% with increasing MWCNT content in the composite nanofiber and was attributed to promotion of electron transfer via charge-transfer complexes formed by carbon nanotubes (Wang, Z.-G., et al. 2006). 

S. Kundu, Y. Wang, W. Xia, M. Muhler, Thermal stability and redudbUity of oxygen-containing functional groups on multi walled carbon nanotube surfaces a quantitative high-resolution XPS and TPD/ TPR study, J. Phys. Chem. C112 (2008) 16869-16878. 

S. Kundu, W. Xia, W. Busser, M. Becker, D.A. Schmidt, M. Havenith, M. Muhler, The formation of nitrogen-containing functional groups on carbon nanotube surfaces a quantitative XPS and TPD study, Phys. Chem. Chem. Phys. 12 (2010) 4351 59. 

Carbon nanotubes (CNTs) functionalized with cyclotriphosphazene-containing polyphosphazenes (164) were found to be useful in the generation and immobilization of gold nanoparticles on the surface of the CNTs as shown in diagram (165) (Scheme 25). ... 

Due to their moderate specific surface area, carbon nanotubes alone demonstrate small capacitance values. However, the presence of heteroatoms can be a source of pseudocapacitance effects. It has been already proven that oxygenated functional groups can significantly enhance the capacitance values through redox reactions [11]. Lately, it was discovered that nitrogen, which is present in carbon affects also the capacitance properties [12]. 

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). 

An important route to solubilization of carbon nanotubes is to functionalize their surface to form groups that are more soluble in the desired solvent environment. It has been shown that acid treatment of nanotube bundles, particularly with HC1 or HNO3 at elevated temperatures, opens up the aggregate structure, reduces nanotube length, and facilitates dispersion (An et al., 2004 Kordas et al., 2006). Nitric acid treatment oxidizes the nanotubes at the defect sites of the outer graphene sheet, especially at the open ends (Hirsch, 2002 Alvaro et al., 2004), and creates carbonyl, carboxyl, and hydroxyl groups, which aid in their solubility in polar solvents. 

Maehashi et al. (2007) used pyrene adsorption to make carbon nanotubes labeled with DNA aptamers and incorporated them into a field effect transistor constructed to produce a label-free biosensor. The biosensor could measure the concentration of IgE in samples down to 250 pM, as the antibody molecules bound to the aptamers on the nanotubes. Felekis and Tagmatarchis (2005) used a positively charged pyrene compound to prepare water-soluble SWNTs and then electrostatically adsorb porphyrin rings to study electron transfer interactions. Pyrene derivatives also have been used successfully to add a chromophore to carbon nanotubes using covalent coupling to an oxidized SWNT (Alvaro et al., 2004). In this case, the pyrene ring structure was not used to adsorb directly to the nanotube surface, but a side-chain functional group was used to link it covalently to modified SWNTs. 

With the aid of a bi-functionalized reagent (terminated with pyrenyl unit at one end and thiol group at the other end), gold nanoparticles were self-assembled onto the surface of solubilized carbon nanotubes [147], Raman spectrum of the gold nanoparticle bearing CNTs is enhanced possibly due to charge transfer interactions between nanotubes and gold nanoparticles. 

Amide bond is an effective anchor to connect CNTs to substrate surfaces. Lan et al. [52] covalently assembled shortened multi-walled carbon nanotubes (s-MWNT) on polyelectrolyte films. The shortened MWNT is functionalized with acyl chloride in thionyl chloride (SOCl2) before self-assembling. The FTIR spectrum of self-assem-bled MWNT (SA-MWNT) adsorbed on a CaF2 plate modified with PEI/(PSS/PEI)2 shows two characteristic absorption peaks at 1646cm-1 (amide I bond) and 1524cm-1 (amide II bond) resulting from the amide bond formed between the polyelectrolyte films and s-MWNTs. 

S. Lefrant, I. Baltog, M. Baibarac, J. Schreiber, and O. Chauver, Modification of surface-enhanced Raman scattering spectra of single-walled carbon nanotubes as a function of nanotube film thickness. Phys. Rev. B 65, 235401.1- 235401.9 (2002). 

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