Carbon nanotubes modified surface

Nanotube patterned films were prepared by Park [3] using surface-modified carbon nanotubes with polyoxetanes. 

Vaisman L, Marom G, Wagner HD. Dispersions of surface-modified carbon nanotubes in water-soluble and water-insoluble polymers. Adv Funct Mater 2006 16 357-63. 

Taking into consideration that only the inner wall surface of carbon nanotubes is exposed to atmosphere in the stage of carbon-deposited alumina film, it would be possible to modify only the inner surface if the carbon-deposited alumina film is chemically treated. On the basis of this concept, Hattori et al. tried to fluorinate only the inner surface of carbon nanotubes (42). It is well known that fluorination is quite an effective way to introduce strong hydrophobicity to carbonaceous materials, and it perturbs the carbon it electron system (43,44). Thus, by the selective fluorination of nanotube s inner surface, it would be possible to produce carbon nanotubes whose inner surface is highly hydrophobic and electrically insulating while their outer... 

The amine function served also as the starting point for the first covalent linkage of Pcs to single-walled carbon nanotubes (SWNTs) [94], The pipes with open-end and surface-bound acyl chloride moieties were used to prepare the Pc-SWNTs system by amide-bond formation (Fig. 14). Accordingly, statistical reaction of 4-aminophthalonitrile with 4-tcr/-bu(yIph111alonitrile in the presence of zinc ions delivered the monoamino Pc that was then employed in the conjugation with the acid chloride modified carbon nanotubes (CNTs). Here, it should also be mentioned that other functions have been applied to the covalent modification of CNTs, i.e., amide [95], ester [96,97], or click chemistry [98],... 

Two weak signals related to the nitro group were observed at 1538 and 1340 cm-i for ox-N-MWCNTs. Similar spectra have been reported for oxidized multiwall carbon nanotubes characteristic poaks were assigned to carboxylic, carbonyl, and hydroxyl group (Wang et al., 2007). These results have probe that sp>ectra carefully acquired by FTIR-ATR are a useful tool for identification of chemical group attached to surface of carbon nanotubes chemically modified. 

Deep gray products, which are soluble in common organic solvents such as chloroform and 1,2-dichlorobenzene are obtained. If the PVK chains are grafted onto the surface of the carbon nanotubes, all of the PVK-modified carbon nanotubes in chloroform show a better optical limiting behavior than those of Ceo in toluene [23],... 

Oligonucleotides have frequently been used in the eonstruction of nanodevices where they are used as a means of detection, as electrical wires or as a scaffold (see also section on nanodevices in section 3.5). A real-time DNA detection method using ssDNA-modified nanoparticles and micropatterned chemoresponsive diffraction gratings has been reported that allows hybridisation detection of 40-900 femtomoles of surface-bound DNA. ° Carbon nanotubes are widely used for the construction of nanodevices, and DNA-functionalised carbon surfaces and nanotubes have been reported as platforms for electrochemical detection of hybridisation.PNA-modified carbon nanotubes have similarly been used for the detection of hybridisation with DNA. DNA conjugated to carbon and other solid surfaces may additionally be used as molecular wires,and carbon-modified nanotubes have been developed that act as a field-effect transistor. 

Figure 4 (A) AFM images (a) MWNTs/CoTMPyP/RCI film assembled on GC electrode (before electrochemical reduction) (b) MWNTs/CoTMPyP/R hybrid film (after electrochemical reduction at - 0.7 V in N2-saturated 0.1 mol I KCI solution). (B) XPS data of MWNTs/CoTMPyP film on GC surface (cun/es (a) and (b)) and MWNTs/CoTMPyP/RCii" film in the R (4f) region before (cun/e (c)) and after (cun/e (d)) electrochemical reduction. (Qu JY, Shen Y, Qu XH, and Dong SJ (2004) Preparation of hybrid thin film modified carbon nanotubes on glassy carbon electrode and its electrocatalysis for oxygen reduction. Chemical Communications 2004 34-35 reproduced by permission of The Royal Society of Chemistry.)...

Park C, Qunaies Z, Watson K A, Crooks R E, Joseph S J, Lowther S E, Connell J W, Siochi E J, Harrison J S and Clair T L (2002) Dispersion of single wall carbon nanotubes by in situ polymerization under sonication, Chem Phys Lett 364 303-308. Vaisnian L, Maron G and Wagner H D (2006) Dispersions of surface-modified carbon rianotubes in water-soluble and water-insoluble polymers, Adv Funct Mater 16 357-363. 

Figure 17.4 Cartoon representation of strategies for studying and exploiting enzymes on electrodes that have been used in electrocatalysis for fuel cells, (a) Attachment or physisorption of an enzyme on an electrode such that redox centers in the protein are in direct electronic contact with the surface, (b) Specific attachment of an enzyme to an electrode modified with a substrate, cofactor, or analog that contacts the protein close to a redox center. Examples include attachment of the modifier via a conductive linker, (c) Entrapment of an enzyme within a polymer containing redox mediator molecules that transfer electrons to/from centers in the protein, (d) Attachment of an enzyme onto carbon nanotubes prepared on an electrode, giving a large surface area conducting network with direct electron transfer to each enzyme molecule.

Figure 15.14 The NHS ester of a pyrene butyric acid derivative can be used to modify a carbon nanotube by adsorption of its rings onto the surface of the tube. The NHS ester groups then can be used to couple amine-containing molecules to form amide bonds.

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. 

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. 

---