Nanofibre

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).

Their antimicrobial activities were found to be improved compared with those of silver(i) nitrate. Encapsulation of 69 by electrospun tecophilic nanofibres for the formation of antimicrobial nanosilver particles was also achieved. 

Bezemer G.L., Bitter J.H., Kuipers H.P.C.E., Oosterbeek H., Holewijn J.E., Xu X., Kapteijn F., van Dillon A.J., and de Jong K.P. 2006. Cobalt particle size effects in the Fischer-Tropsch reaction studied with carbon nanofibre supported catalysts. J. Am. Chem. Soc. 128 3956-64. 

This review will discuss the possibility to control and improve the reactivity of Titania by design of new tailored nano-architecture. Specifically, analyses quasi-ID Ti02 nanostructures, e.g. nanorods, nanowires and nanofibres, nanotubes and nanopillars. 2D Titania nanostructures, e.g. columnar-type films, ordered arrays of nanotubes or nano-rods/-wires, nanobowl array, nanomembranes (called also nanohole array) and nanosponge, and Ti-based ordered mesoporous matrices will be instead discussed in a consecutive review paper. 

Research advances in the last few years have significantly progressed the possibility of developing new nanostructured Titania catalysts having controllable phase and architecture. This review is limited to quasi-1D Ti02 nanostructures, e.g. nanorods, nanowires and nanofibres, nanotubes and nanopillars. 

Oroudjev, E., Soares, J., Arcdiacono, S., Thompson, J. B., Fossey, S. A., and Hansma, H. G. (2002). Segmented nanofibres of spider dragline silk Atomic force microscopy and single-molecule force spectroscopy. Proc. Natl. Acad. Sci. USA 99, 6460-6465. 

Wang X, Kim Y-G, Drew C, Ku B-C, Kumar J, Samuelson LA (2004) Electrostatic assembly of conjugated polymer thin layers on electrospun nanofibrous membranes for biosensors. 

Long Y, Chen H, Yang Y, Wang H, Yang Y, Li N, Li K, Pei J, Liu F (2009) Electrospun nanofibrous film doped with a conjugated polymer for DNT fluorescence sensor. Macromolecules 42 6501-6509... 

Burger C, Chu B (2007) Functional nanofibrous scaffolds for bone reconstruction. Colloid. Surf. B 56 134-141. 

Sung JH, Kim HS, Jin HJ, Choi HJ, Chin IJ (2004). Nanofibrous membranes prepared by multi-walled carbon nanotube/poly(methyl methacrylate) composites. Macromolecules 37 9899-9902. 

Figure 1. Amount of hydrogen adsorbed at 298 K and 20 MPa by activated carbons (open symbols) and carbon nanotubes and nanofibres (closed symbols) versus the total micropore volume [Vpp (N )] (Figure 1(a)) and the narrow micropore volume [Vnpp (DR.CCty] (Figure 1(b)).

As observed in Figure 3, the results obtained for carbon nanofibres and nanotubes (closed symbols) fit in the tendencies obtained for activated carbons, showing that hydrogen adsorption depends on the porosity of the sample and does not depend on its structure. 

S. Helveg, C. Lopez-Cartes, J. Sehested, P. Hansen, B. Clausen, J. Rostrup-Nielsen, F. Abild-Pedersen, and J. Norskov, Atomic-scale imaging of carbon nanofibre growtti. Nature 427,426-429 (2004). 

Figure 7.5 shows, for the same period, the relative number of recent patents per fibre type. Nanotubes and nanocomposites, particularly carbon nanotubes, are generating intense research activity whereas research is definitely weaker for nanofibres. Figure 7.6 shows, for the same period, the recent patents for the different nano-reinforcements. 

Kannan, Menghal, and Barsukov [165] and Kannan and Munukutla [166] used a new form of parfially ordered graphitized nanocarbon black, called Pureblack carbon, as parf of fhe MPL for a carbon fiber paper DL. In addition, the nanocarbon black was mixed with nanofibrous carbon (Showa Denko) in order to improve mechanical strength. It was demonstrated that this composite MPL with Pureblack and the nanofibrous carbon performed better than an MPL with Vulcan CX-72R under fully humidified and ambienf pressure conditions, especially at higher current densities. 

One final example of multiple layer MPL was presented by Karman, Cindrella, and Munukutla [172]. A four-layer MPL was fabricated by using nanofibrous carbon, nanochain Pureblack carbon, PIPE, and a hydrophilic inorganic oxide (fumed silica). The first three layers were made out of mixtures of the nanofibrous carbon, Pureblack, carbon, and PTFE. Each of these three layers had different quantities from the three particles used. The fourth layer consisted of Pureblack carbon, PTPE, and fumed silica to retain moisture content to keep the membrane humidified. Therefore, by using these four layers, a porosity gradient was created that significantly improved the gas diffusion through the MEA. In addition, a fuel cell with this novel MPL showed little performance differences when operated at various humidity conditions. 

Gupta, B.K., Srivastava, O.N. 2000. Synthesis and hydrogenation behaviour of graphitic nanofibres. Int J Hydrogen Energy 25 825-830. 

Saita et al. [80] applied hydriding chemical vapor deposition (HCVD) for preparing MgH. They used commercial Mg, which was heated to 600°C and vaporized in a hydrogen atmosphere at a pressure of 4 MPa. The reaction product was deposited on a cooled Inconel substrate and subsequently collected for further investigation. Quite remarkably, the obtained morphology was nanofibrous, as shown in Fig. 2.47, and is very similar to the one fabricated by Zlotea et al. [79]. Each fiber was less than 1 jm in diameter and 10 or more micrometers in length. 

SUPRAMOLECULAR POLYMERIZATION OF PEPTIDES AND PEPTIDE DERIVATIVES NANOFIBROUS MATERIALS... 

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