Poly /MWCNT

The group in the Swiss Federal Institute of Technology [55] has fabricated a macroscale device by depositing the conducting polymer (poly(/j-phenylenevinylene)) on the MWCNT film (Fig. 16). They have observed the characteristic rectifying effect from the l-V curve, which suggests the CNTs inject holes efficiently into the polymer layer. However, due to the difficulty in... 

Fig. 1.16 Schematic representation of the nanofibrous poly (acrylonitrile-co-acrylic acid) membrane containing MWCNTs, as well as the promoted electron transfer from hydrogen peroxide to the immobilized catalase through the PANCAA/MWCNTs nanofiber. Reprinted from [209] (reproduced by permission ofWiley-VCH).

D. H. Zhang, M. A. Kandadai, J. Cech, S. Roth, S. A. Curran, Poly(L-lactide) (PLLA)/multiwalled carbon nanotube (MWCNT) composite Characterization and biocompatibility evaluation, Journal of Physical Chemistry B, vol. 110, pp. 12910-12915, 2006. 

Lin et al. oxidized MWCNTs and followed by mixing with poly(allylamine hydrochloride) (PAH) [84]. A higher coverage of PAH was obtained when KN03 was added to increase the ionic strength of the solution. A solution containing H2PtCl6... 

CVD processes can also be used to grow polymers from nanocarbons. An important example is the coating of a CNT forest with a thin layer of poly(tetrafluorethlylene) (PTFE) via hot filament CVD to produce a superhydrophobic substrate [245]. Here, a vertically aligned MWCNT forest was prepared and placed in a CVD reaction chamber. Hexafluorpropylene oxide gas was then thermally decomposed to form the reactive radical difluorocarbene (CF2) and flowed over the CNT substrate along with a small amount of initiator where direct polymerization of PTFE onto the CNTs occurred [245]. 

Bhandari, S. Deepa, M. Srivastava, A. K. Lai, C. Kant, R., Poly(3,4-Ethylenedioxythiophene) (Pedot)-Coated Mwcnts tethered to conducting substrates Facile electrochemistry and enhanced coloring efficiency. Macromol Rapid Commun 2009, 30,138-138. 

Fig. 18.6 Upper part - chemical structures of poly(oxyethylene)-segmented (POE) and amides and imides polymer derivatives (POEM). Lower left part - chemical structure of 15-crown-5-functionalized MWCNT. Lower right part - chemical structure of l-(2-acryloyloxy-ethyl)-2-methyl-benzoimidazol-l-ium iodide (AMIml).

Ferrocene was one of the earliest mediators used [10] but is somewhat hydrophobic so derivatives of the molecule are often employed [39-43]. Ferricyanide can also be used, and the use of MWCNT with this mediator was shown to enhance its effectiveness [33]. Other groups have studied a wide diversity of novel mediator systems such as poly(vinylferrocene-co-acrylamide) dispersed within an alumina nanoparticle membrane [34], ruthenium [35] and osmium [36,37] complexes, and the phenazine pigment pyocyanin, which is produced by the bacteria Pseudomonas aeruginosa [38]. 

MWCNTs were functionalized with iron phthalocyanines (FePc) to improve the sensitivity towards hydrogen peroxide. A highly sensitive glucose sensor with an FePc-MWCNT electrode based on the immobilization of GOx on poly(o-amino-phenol) (POAP)-electropolymerized electrode surface [219]. A hemin-modified MWCNT electrode to be used as a novel 02 sensor was obtained by adsorption of hemin at MWCNTs and the electrochemical properties of the electrode were characterized by cyclic voltammetry [220]. 

Jin et al. (65) used poly(vinylidene fluoride) (PVDF) as a compatibilizer to assist dispersion of CNTs in PMMA. Multi-walled carbon nanotubes were first coated with PVDF and then melt-blended with PMMA. Poly(vinylidene fluoride) served as an adhesive to improve wetting of CNTs by PMMA and to increase the interfacial adhesion resulting in improved mechanical properties of MWCNT-PMMA composites. 

Kim et al. (66) used poly(3-hexylthiophene) (P3HT)-graft-PMMA as a compatibilizer to prepare MWCNT-PMMA composites by solution blending. The CNT content was varied from 0.01 to 0.1 wt%. The resulting composites showed improved tensile strength and modulus. 

Jia etal. 1999 (23) MWCNT CVD Untreated tubes Treated tubes In situ polymerization Improved In situ polymerization CNT Loading levels 1 to 10 wt% Tensile Strength, fracture toughness and hardness increased with CNT loading from 0 to 7 wt% using treated tubes and improved method Tensile Strength Untreated tubes Treated tubes In situ poly. Improved In situ poly. Wt% MPa Wt% MPa 0 54.9 3 66.8 1 21.2 5,7 71.7 3 20.3 10 47.2 FTIR and SEM studies revealed CNT participation in PMMA polymerization and presence of a strong interface between CNTs and PMMA ... 

In consequent experiments, the authors (16) innovated the preparation procedure in order to improve the quality of prepared PMMA/ MWCNT particles they profitably used a steric stabilizer, poly(vinyl pyrrolidone) (PVP) (48). PVP has both hydrophobic and hydrophilic... 

As described above, ILs for functionalization of CNTs are generally low molecular organic salts. Recently, Chen et al. [146] have employed PIL-functionalized MWCNTs to serve as the templates for fabrication of metal NP hybrids. In this method, the IL of 3-ethyl-l-vinylimidazolium tetrafluoroborate (EVimBF ) was in situ polymerized to form a poly(EVunBF ) shell on the surface of MWCNTs (Fig. 15.11). This not only makes MWCNTs uniform dispersion in water but also serves as the medium to stabilize and grow metal NPs. It is noted that metal NPs (e.g., Pt, PtRu) are uniformly dispersed on the supported surface of poly(EVimBF )/... 

Fig. 15.11 Schematic diagram of the preparation of Pt/poly(EVimBF )/MWCNT hybrids EG ethylene glycol, AIBN 2,2 -azobisisobutyronitrile)...

Cytochrome c MWCNT/poly(amidoamine)/ chitosan modified GCE Nitrite biosensor [119]... 

---