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Collective mechanism for the evolution and self-termination of vertically aligned carbon nanotube growth
M. Bedewy, E.R. Meshot, H. Guo, E.A. Verploegen, W. Lu, A.J. Hart. Journal of Physical Chemistry C 113:20576-20582, 2009. [http://pubs.acs.org/doi/abs/10.1021/jp904152v] [PDF] We explain the evolution and termination of vertically aligned carbon nanotube (CNT) “forests” by a collective mechanism, which is verified by temporal measurements of forest mass and height, as well as quantitative spatial…
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John Hart receives Outstanding Young Manufacturing Engineer Award
October 2009: John Hart will receive the 2010 Society of Manufacturing Engineers (SME)Outstanding Young Manufacturing Engineer Award, recognizing exceptional contributions and accomplishments in the manufacturing industry.
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Early evaluation of potential environmental impacts of carbon nanotube synthesis by chemical vapor deposition
D.L. Plata, A.J. Hart, C.M. Reddy, P.M. Gschwend. Environmental Science and Technology 43(21):8367-8373, 2009. [http://pubs.acs.org/doi/abs/10.1021/es901626p] [PDF] The carbon nanotube (CNT) industry is expanding rapidly, yet little is known about the potential environmental impacts of CNT manufacture. Here, we evaluate the effluent composition of a representative multiwalled CNT synthesis by catalytic chemical vapor deposition (CVD)…
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Jinjing Li, Megan Roberts and Aaron Schmidt Join
September 2009: Jinjing Li, Megan Roberts, and Aaron Schmidt join the Mechanosynthesis Group – people
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High-yield growth of vertically aligned carbon nanotubes on a continuously moving substrate
R. Guzman de Villoria, S.L. Figueredo, A.J. Hart, S.A. Steiner, A.H. Slocum, B.L. Wardle. Nanotechnology 20:405611, 2009. [http://dx.doi.org/10.1088/0957-4484/20/40/405611] [PDF] Vertically aligned carbon nanotube (CNT) arrays are grown on a moving substrate, demonstrating continuous growth of nanoscale materials with long-range order. A cold-wall chamber with an oscillating moving platform is used to locally heat a silicon…
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Low temperature synthesis of vertically aligned carbon nanotubes with electrical contact to metallic substrates enabled by thermal decomposition of the carbon feedstock
G.D. Nessim, M. Seita, K.P. O’Brien, A.J. Hart, R.K. Bonaparte, R.R. Mitchell, C.V. Thompson. Nano Letters 9(10):3398-3405, 2009. [http://dx.doi.org/10.1021/nl900675d] [PDF] Growth of vertically aligned carbon nanotube (CNT) carpets on metallic substrates at low temperatures was achieved by controlled thermal treatment of ethylene and hydrogen at a temperature higher than the substrate temperature. High-resolution transmission…
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Storing elastic energy in carbon nanotubes
F.A. Hill, T.F. Havel, A.J. Hart, C. Livermore. Journal of Micromechanics and Microengineering 19:094015, 2009. [http://dx.doi.org/10.1088/0960-1317/19/9/094015] [PDF] The potential performance of carbon nanotubes (CNTs) as springs for elastic energy storage is evaluated. Models are used to determine an upper bound on the energy density that can be stored in defect-free individual CNTs and in…
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Diffusional self-organization in exponential layer-by-layer films with micro and nanoscale periodicity
P. Podsiadlo, M. Michel, K. Critchley, S. Srivastava, M. Qin, J.W. Lee, E.A. Verploegen, A.J. Hart, Y. Qi, N.A. Kotov. Angewandte Chemie International Edition 48(38):7073–7077, 2009. [http://dx.doi.org/10.1002/anie.200901720] [PDF] The layer-by-layer deposition of poly(diallyldimethylammonium chloride) and poly(acrylic acid) incorporating inorganic sheets of sodium montmorillonite clay leads to a stratified structure throughout the film interior, with…
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Multifunctional properties of high volume fraction aligned carbon nanotube polymer composites with controlled morphology
H. Cebici, R. Guzman de Villoria, A.J. Hart, B.L. Wardle. Composites Science and Technology 69:2649-2656, 2009. [http://dx.doi.org/10.1016/j.compscitech.2009.08.006] [PDF] Advanced composites, such as those used in aerospace applications, employ a high volume fraction of aligned stiff fibers embedded in high-performance polymers. Unlike advanced composites, polymer nanocomposites (PNCs) employ low volume fraction filler-like concepts with randomly-oriented…
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Engineering vertically aligned carbon nanotube growth by decoupled thermal treatment of precursor and catalyst
E.R. Meshot, D.L. Plata, S. Tawfick, Y.Y. Zhang, E.A. Verploegen, A.J. Hart. ACS Nano 3(9):2477-2486, 2009. [http://dx.doi.org/10.1021/nn900446a] [PDF] We study synthesis of vertically aligned carbon nanotube (CNT) “forests” by a decoupled method that facilitates control of the mean diameter and structural quality of the CNTs and enables tuning of the kinetics for efficient growth…