Functionalised CNTs

SWCNT—(C02H) 89-90% SWCNT (carbonaceous purity), bundle dimension diam 4-5nm x length 

SWCNT-(ODA) SWCNT-[CONHCH2(CH2)i6CH3)1 , octadecylamide functionalised, 89-90 /o SWCNT (carbonaceous purity), bundle dimension diam 2-lOnm x length 0.5-2.0pm, average diameter of individual SWCNT being 1.4nm 0.1nm. It is prepared from the above SWCNT-(COCl) (obtained from 

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The covalent functionalisation of CNTs is the alternative and extremely promising approach for applications in fields such as that of functional and composite materials and that of biology. According to the location of the functional groups, two main strategies are used to covalently functionalise CNTs with biomolecules (i) defect functionalisation, and (ii) sidewall functionalisation. 

Studies from our laboratories by Pantarotto et al. (2004a, b), Wu et al. (2005) and Kostarelos et al. (2007) using covalently functionalised CNTs (1,3-dipolar cycloaddition reaction chemistry) have reproducibly described that CNTs were uptaken by cells via pathways other than endocytosis. This work has experimentally observed that CNTs were able to interact with plasma membranes and cross into the cytoplasm without the apparent need of engulfment into a cellular compartment... 

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. 

The ehapter is organised as follows. After the introduction, a brief overview of the fundamentals of CNTs and CNT-based FETs will be given. The next section describes a range of chemical functionalisation schemes that have been devised for the performance enhancement of CNT-FETs. The subsequent section is devoted to the characterisation of as-prepared and functionalised CNT-FETs through electrical transport measurements and scanning photocurrent microscopy. In this context, the relevant device parameters of the FETs such as saturation behaviour, field-effeet mobility, transconductance and sub-threshold slope will be analysed and compared. The chapter concludes with future perspectives for the fabrication of CNT-based FETs. 

With CNTs becoming easier to produce and much cheaper to buy, CNT-based manufacturing could potentially overtake that of the carbon fibre industry and result in a number of new commercial polymer composite products. However, there are still many challenges in this area including the development of functionalised CNTs as additives for polymer reinforcement. 

Oxidation by ozonolysis is one of generic set of techniques which is utilised to functionalise CNTs. For example, in one recent work MWNTs oxidised by ozonolysis were then modified with long-alkyl chains via an esterification process. These MWNTS were used to produce PVC composites, which demonstrated improved solubility in organic solvents. ... 

The grafting to method was used for the preparation of composites with the polymers containing reactive functional groups. One of the first examples of the grafting to approach was published by Fu et al in 2001. In this work, carboxylic acid groups on the nanotube surface were converted into acyl chlorides by refluxing the samples in thionyl chloride. Then the acyl chloride functionalised CNTs have been reacted with hydroxyl groups of dendritic PEG polymers via esterification reactions. 

Another paper " reported the development of two main strategies (i) the covalent grafting of hydrolyzable Si(OEt)3 groups on oxidised CNTs and (ii) the non-covalent adsorption of a polycation on pristine CNTs (Figure 4.9). These approaches enabled the performance of further sol-gel processing of functionalised CNTs and their incorporation into poly(methyl methacrylate)... 

The Young s moduli and dT/dFf values of some polymer composites that contain various functionalised CNTs are summarised in Table 4.3. 

Table 4.3 Mechanical properties of selected polymer composites containing functionalised CNTs. 

For examples of some currently commercial CNTs and functionalised CNTs see the following paragraphs. CARBON NANOTUBES (CNTs)... 

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