Nanotube chemically modified

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. 

Zhao J, Lee CW et al (2009) Solution-processable semiconducting thin-film transistors using single-walled carbon nanotubes chemically modified by organic radical initiators. Chem Commun (Camb, UK) 46 7182-7184... 

In recent years, CNTs have been receiving considerable attention because of their potential use in biomedical applications. Solubility of CNTs in aqueous media is a fundamental prerequisite to increase their biocompatibility. For this purpose several methods of dispersion and solubilisation have been developed leading to chemically modified CNTs (see Paragraph 2). The modification of carbon nanotubes also provides multiple sites for the attachment of several kinds of molecules, making functionalised CNTs a promising alternative for the delivery of therapeutic compounds. 

Attaching chemical functionalities to CNTs can improve their solubility and allow for their manipulation and processability [24]. The chemical functionalization can tailor the interactions of nanotubes with solvents, polymers and biopolymer matrices. Modified tubes may have physical or mechanical properties different from those of the original nanotubes and thus allow tuning of the chemistry and physics of carbon nanotubes. Chemical functionalization can be performed selectively, the metallic SWCNTs reacting faster than semiconducting tubes [25]. 

Single-walled carbon nanotubes, SWNT, having a diameter of 0.7 nm were electro-chemically derivatized on the sides and ends with diazonium tetrafluoroborate derivatives. In this process the estimated degree of functionality was about 1 out of every 20 to 30 carbons in the nanotube. These chemically modified nanotubes have applications in polymer composite materials, molecular electronic applications, and sensor devices. 

When the tip is functionalized with a chemical species, chemical discrimination can be achieved (chemical force microscopy, CFM) [236, 237]. Covalently functionalized nanotubes can be prepared, allowing chemical contrast between areas with different SAM layers [238]. For biomolecular applications tips can be chemically modified by a layer of molecules that bind especially strongly to complementary molecules. Insight into mechanical properties of biomolecules, such as binding/recognition interactions, unfolding, and elasticity of complex biomolecules has been gained on the basis of force-distance curves [239-243]. 

Covalent functionalisation and the surface chemistry of CNTs have been envisaged as very important factors for the processing and applications of nanotubes. Recently, many efforts on polymer composite reinforcement have been focused on an integration of chemically modified nanotubes containing different functional groups into the polymer matrix. Covalent functionalisation of CNTs can be achieved by either direct addition reactions of reagents to the sidewalls of nanotubes or the modification of appropriate surface-bound functional e.g. carboxylic acid) groups on to the nanotubes. " ... 

Regarding the nanotubes, it was possible to establish carbon functional group present in the surface of them once these were chemically modified. This is important since this allows figuring out what kind of interactions with other materials could be taken place, and understanding the mechanism of such interactions. 

Natural amylose and its chemically modified form, i.e., CMAs and MAs, possess basically a rigid cavity, and therefore, they can include guest molecules or polymers in a size-selective manner because the cavity can act flexibly in an induced-fit manner, being different from those of cyclodextrines (CDs). From the stand point of the nanotube structure, this is in contrast to CD hosts in rigidity and ring structures. 

Jiang, M.-J. Dang, Z.-M. Xu, H.-P., Enhanced Electrical Conductivity in Chemically Modified Carbon Nanotube/Methylvinyl Silicone Rubber Nanocomposite. Ear. Polym. J. 2007, 43, 4924-4930. 

Therefore, the key step for the in-situ polymerization of PUCNs is the dispersion of CNTs in macromolecular polyols. In order to reduce the aggregations, it is necessary to physically or chemically modify the surface of CNTs to reduce the van der Waals force among the nanotubes. Strong mechanical tools such as ball milling and ultrasonic treatment can be used to help break down the aggregation of CNTs. The kinetics of PU chain growth should be taken into account although it is rarely reported in up-to-date publicahons. 

Kim Y J, Shin T S, Choi H D, Kwon J H, Chung Y C and Yoon H G (2005) Electrical conductivity of chemically modified multiwalled carbon nanotube/epoxy composites. Carbon 43 23-30. 

Substances that have been used in this context include glass fiber (occasionally glass beads), carbon fiber, carbon nanotubes, carbon black, graphite, fuUerenes, graphite chemically modified clays and montmorillonites, silica, and mineral alumina. Other additions have been included in polymer formulations, including calcium carbonate, barium sulfate, and various miscellaneous agents, such as aluminum metal, oak husks, cocoa shells, basalt fiber, silicone, rubbery elastomers, and polyamide powders. The effects of such additions of polymer properties are discussed next. 

The WE, typically a cathode, is generally where the reaction of interest occurs. Typical WEs (see Chapters 5 and 6) include the noble metals (especially gold and platinum), carbon (including pyrolytic carbon, glassy carbon, carbon paste, nanotubes, and vapor-deposited diamond), liquid metals (mercury and its amalgams), and semiconductors (indium-tin oxide. Si, see Chapter 9). WEs can be chemically modified (see Chapter 8) in order to increase their sensitivities toward specific species (i.e., become chemical sensors) or to decrease the potential required to drive a particular reaction (i.e., catalysis). 

The functionalized carbon nano tubes can present different mechanical and electrical properties when compared to the unfimctionalized carbon nanotubes. These chemically modified structures can be used to facilitate the interaction of the nanotubes with organic and biological molecules and with other chemical groups as toxic molecules, drugs, and even viruses and bacteria (FUho and Fagan 2007). 

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