Growth Model, Synthesis of Carbon Nanostructures and Alteration of Surface Properties Using Them

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dc.contributor.authorNaha, Sayangdeven
dc.contributor.committeechairPuri, Ishwar K.en
dc.contributor.committeememberLesko, John J.en
dc.contributor.committeememberMahajan, Roop L.en
dc.contributor.committeememberPatil, Mayuresh J.en
dc.contributor.committeememberCramer, Mark S.en
dc.contributor.committeememberHajj, Muhammad R.en
dc.contributor.departmentEngineering Science and Mechanicsen
dc.date.accessioned2014-03-14T20:14:52Zen
dc.date.adate2008-08-26en
dc.date.available2014-03-14T20:14:52Zen
dc.date.issued2008-07-25en
dc.date.rdate2008-08-26en
dc.date.sdate2008-08-07en
dc.description.abstractFlame synthesis is recognized as a much cheaper and higher throughput process for carbon nanotube/nanofiber (CNT/CNF) production compared to conventional catalytic processes like chemical vapor deposition (CVD). Nanostructured carbon materials, such as carbon nanotubes and nanofibers, exhibit superhydrophobic behavior over a range of pH values, including for corrosive liquids. Part of this research reports the development of a rapid on-demand process for the synthesis of superhydrophobic surfaces on silicon (Si) discs using an ethylene-air nonpremixed flame. Such superhydrophobic behavior, combined with increase in effective surface area due to carbon nanostructure (CNS) deposition and corresponding desirable size (nanoscale roughness) attract the growth and attachment of microbial colonies to these CNS-enhanced substrates. This has potentially high-impact application in microbial fuel cells (MiFCs) whereby stainless steel (SS) meshes coated with flame-deposited CNS are used as anodes and the electrons produced by attaching biofilms can generate electricity in a fuel cell. However, despite such and many other applications and promise of carbon nanotubes (CNTs), their production is generally based on empirical principles. There are only a few CNT formation models that predict the dependence of CNT growth on various synthesis parameters. Typically, these do not incorporate a detailed mechanistic consideration of the various processes that are involved during CNT synthesis. Herein, this need is addressed and a model is presented for catalytic CNT growth that integrates various interdependent physical and chemical mechanisms involved in CNT production. It is validated by comparing its predictions with experimental measurements for CVD synthesis of CNTs and a concise parametric study is presented. The results are extrapolated for flame synthesis that is recognized as a desirable cost-effective process for the bulk synthesis of CNTs, as already mentioned. The last part of this dissertation discusses an extension of the CNT growth model to silicon nanowire/nanowhisker (SiNW) synthesis. SiNWs are synthesized by a number of methods — catalysis by a metal (involving vapor-liquid-solid or VLS growth mode), molecular beam epitaxy, thermal evaporation and laser ablation to name a few. Our model pertains to metal-catalyzed VLS growth mode.en
dc.description.degreePh. D.en
dc.identifier.otheretd-08072008-105548en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-08072008-105548/en
dc.identifier.urihttp://hdl.handle.net/10919/28559en
dc.publisherVirginia Techen
dc.relation.haspartThesis_Naha_ETD.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectcarbon nanofibersen
dc.subjectcatalysisen
dc.subjectnanotechnologyen
dc.subjectflame synthesisen
dc.subjectsilicon nanowiresen
dc.subjectsuperhydrophobicityen
dc.subjectCarbon nanotubesen
dc.titleGrowth Model, Synthesis of Carbon Nanostructures and Alteration of Surface Properties Using Themen
dc.typeDissertationen
thesis.degree.disciplineEngineering Science and Mechanicsen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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