Show simple item record

Dynamics and Limiting Mechanisms of Self-Aligned Carbon Nanotube Growth.

dc.contributor.authorMeshot, Eric Ryanen_US
dc.description.abstractCarbon nanotubes (CNTs) are long, cylindrical molecules, which boast exceptional tensile strength and large thermal and electrical conductivities. Vertically aligned CNT “forests” have promising potential uses, including dry adhesives, electrical interconnects, light emitters, thermal interface materials, gas and liquid filters, composite reinforcements, and photonic crystals. Manufacturing indefinitely long CNTs may realize dreams of CNT-based cables and wires having stiffness, strength, and transport properties exceeding today’s best metal alloys and advanced fibers. However, the functional properties of CNT forests have so far fallen short of those of individual CNTs due to low packing fraction, polydisperse diameters, and relatively short lengths. Toward the eventual goal of bridging this structure-property relationship, my dissertation presents a novel set of in situ and ex situ characterization tools for CNT forest growth by chemical vapor deposition (CVD), as well as the use of these tools to investigate the limiting mechanisms thereof. In situ X-ray scattering reveals the dynamics of catalyst thin film dewetting into nanoparticle growth sites, the initial self-organization of the CNT forest, and the abrupt self-termination of growth. Quantification of catalyst and CNT sizes show that they are inevitably polydisperse, regardless of synthesis conditions. To overcome this, a novel method is introduced for templated dewetting of the catalyst film toward the formation of ordered, monodisperse particles using nanoporous anodic alumina. Further, a map of thermal conditions is explored by independently tuning the temperatures of the catalyst and gaseous precursors, thereby establishing a set of rules for engineering crucial characteristics of forest growth, including CNT diameter, structural quality, vertical alignment, as well as rate and lifetime of the reaction. Finally, aligned CNT ensembles are used as templates to direct the self-assembly of fullerene C60, creating hybrid films with high photoconductive gain, thereby demonstrating an immediate application of this exciting material. These studies represent many new insights into the so-called “birth, life, and death” of CNT growth, and they have important implications for future work in synthesis of advanced carbon materials, including CNTs, fullerenes, and graphene. Meanwhile, these results have immediate applicability to efficient CNT manufacturing, improved characterization, and new hybrid materials for energy conversion.en_US
dc.subjectCarbon Nanotubeen_US
dc.titleDynamics and Limiting Mechanisms of Self-Aligned Carbon Nanotube Growth.en_US
dc.description.thesisdegreedisciplineMechanical Engineeringen_US
dc.description.thesisdegreegrantorUniversity of Michigan, Horace H. Rackham School of Graduate Studiesen_US
dc.contributor.committeememberHart, Anastasios Johnen_US
dc.contributor.committeememberGarikipati, Krishnakumar R.en_US
dc.contributor.committeememberLinic, Suljoen_US
dc.contributor.committeememberPlata, Desiree L.en_US
dc.contributor.committeememberThouless, Michael D.en_US
dc.subject.hlbsecondlevelMechanical Engineeringen_US
dc.owningcollnameDissertations and Theses (Ph.D. and Master's)

Files in this item

Show simple item record

Remediation of Harmful Language

The University of Michigan Library aims to describe library materials in a way that respects the people and communities who create, use, and are represented in our collections. Report harmful or offensive language in catalog records, finding aids, or elsewhere in our collections anonymously through our metadata feedback form. More information at Remediation of Harmful Language.


If you are unable to use this file in its current format, please select the Contact Us link and we can modify it to make it more accessible to you.