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Desktop growth of carbon nanotube monoliths with in situ optical imaging
A.J. Hart, L.C. van Laake, A.H. Slocum. Small 3(5):772-777, 2007. [http://dx.doi.org/10.1002/smll.200600716] [PDF] Fruits of the forest: A desktop reactor rapidly grows forests of aligned carbon nanotubes (CNTs) to heights of many millimeters by atmospheric-pressure chemical vapor deposition (see picture). This low-cost apparatus achieves the reaction temperature by resistive heating of a suspended silicon platform,…
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Quantitative characterization of the morphology of multi-wall carbon nanotube films by small-angle X-ray scattering
B.N. Wang, R.D. Bennett, E. Verploegen, A.J. Hart, R.E. Cohen. J. Physical Chemistry C 111(16):5859-5865, 2007. [http://dx.doi.org/10.1021/jp068895a] [PDF] Films of multiwall carbon nanotubes (MWCNTs) grown by thermal chemical vapor deposition were studied using small-angle X-ray scattering (SAXS). We assessed the extent of alignment of carbon nanotubes (CNTs) by examining relative SAXS intensities as a…
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Fabrication of composite microstructures by capillarity-driven wetting of aligned carbon nanotubes with polymers
E.J. García, A.J. Hart, B.L. Wardle, A.H. Slocum. Nanotechnology 18(16):165602, 2007. [http://dx.doi.org/10.1088/0957-4484/18/16/165602] [PDF] The interaction, or wetting, of long aligned carbon nanotube (CNT) forests with off-the-shelf (no solvent added) commercial thermoset polymers is investigated experimentally. A technique for creating vertically aligned CNT composite microstructures of various shapes is presented. The effective wetting of the…
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Method of characterizing electrical contact properties of carbon nanotube coated surfaces
O. Yaglioglu, A.J. Hart, R. Martens, A.H. Slocum. Review of Scientific Instruments 77:095105, 2006. [http://dx.doi.org/10.1063/1.2349300] [PDF] We present a method for electromechanical characterization of carbon nanotube (CNT) films grown on silicon substrates as potential electrical contacts. The method includes measuring the sheet resistance of a tangled CNT film, measuring the contact resistance between two…
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Controlling the Morphology of Carbon Nanotube Films by Varying the Areal Density of Catalyst Nanoclusters Using Block-Copolymer Micellar Thin Films
R.D. Bennett, A.J. Hart, R.E. Cohen. Advanced Materials 18:2274-2279, 2006. [http://dx.doi.org/10.1002/adma.200600975] [PDF] The morphologies of carbon nanotube (CNT) thin films are controlled by varying the areal density of catalytic nanoclusters synthesized from a block-copolymer micellar thin film. The morphologies of the CNT films vary from a tangled and sparse arrangement of individual CNTs, through…
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Creating Patterned Carbon Nanotube Catalysts through the Microcontact Printing of Block Copolymer Micellar Thin Films
R.D. Bennett, A.J. Hart, A.C. Miller, P.T. Hammond, D.J. Irvine, R.E. Cohen. Langmuir 22:8273-8276, 2006. [http://dx.doi.org/10.1021/la061054a] [PDF] We report a route for synthesizing patterned carbon nanotube (CNT) catalysts through the microcontact printing of iron-loaded poly(styrene-block-acrylic acid) (PS-b-PAA) micellar solutions onto silicon wafers coated with thin aluminum oxide (Al2O3) layers. The amphiphilic block copolymer, PS-b-PAA,…
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Experimental determination of kinematic coupling repeatability in industrial and laboratory conditions
P.J. Willoughby, A.J. Hart, A.H. Slocum. SME J. Manufacturing Systems 24:108-121, 2005. [http://dx.doi.org/10.1016/S0278-6125(05)80011-1] [PDF ] While kinematic couplings are frequently used as components of repeatable interfaces in ideal environments, their use in heavily loaded industrial interfaces is less frequent, as previous studies have validated couplings mostly under modest loads and controlled environmental conditions. On…
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Force output, control of film structure, and micro-scale shape replication by carbon nanotube growth under mechanical pressure
A.J. Hart, A.H. Slocum. Nano Letters 6:1254-1260, 2006. [http://dx.doi.org/10.1021/nl0524041] [PDF] We demonstrate that a film of vertically aligned multiwall carbon nanotubes (CNTs) can exert mechanical energy as it grows, and in our experiments the average force output is approximately 0.16 nN per CNT, for CNTs having an outer diameter of 9 nm and five…
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Rapid growth and flow-mediated nucleation of millimeter-scale aligned carbon nanotube structures from a thin-film catalyst
A.J. Hart, A.H. Slocum. J. Physical Chemistry B 110(16):8250-8257, 2006. [http://dx.doi.org/ 10.1021/jp055498b] [PDF] We discuss the rapid growth of films and lithographically templated microstructures of vertically aligned small-diameter multiwalled carbon nanotubes (VA-MWNTs), by atmospheric-pressure thermal chemical vapor deposition (CVD) of C2H4/H2/Ar on a Fe/Al2O3 catalyst film deposited by electron beam evaporation. The structures grow…
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Uniform and selective CVD growth of carbon nanotubes and nanofibers on arbitrarily microstructured silicon surfaces
A.J. Hart, B.O. Boskovic, A.T.H. Chuang, V.B. Golovko, J. Robertson, B.F.G. Johnson, A.H. Slocum. Nanotechnology 17:1397-1403, 2006. [http://dx.doi.org/10.1088/0957-4484/17/5/039] [PDF] Carbon nanotubes (CNTs) and nanofibres (CNFs) are grown on bulk-micromachined silicon surfaces by thermal and plasma-enhanced chemical vapour deposition (PECVD), with catalyst deposition by electron beam evaporation or from a colloidal solution of cobalt nanoparticles. Growth…