Computational Modeling of Growth and Mechanical Behavior of Carbon-based Nanomaterials
| dc.contributor.advisor | Yakobson, Boris I | en_US |
| dc.creator | Luo, Ming | en_US |
| dc.date.accessioned | 2019-05-16T20:49:58Z | en_US |
| dc.date.available | 2019-05-16T20:49:58Z | en_US |
| dc.date.created | 2017-12 | en_US |
| dc.date.issued | 2018-02-15 | en_US |
| dc.date.submitted | December 2017 | en_US |
| dc.date.updated | 2019-05-16T20:49:58Z | en_US |
| dc.description.abstract | The design of future nanoelectromechanical systems (NEMS) requires new materials which do not conform to classical scale material models. Carbon nanomaterials, exemplified by graphene, a single layer of graphite, and carbon nanotubes (CNTs), rolled up graphene nanoribbon, have attracted great interests due to their extraordinary electronic, thermal, and mechanical properties, promising a rich variety of applications in future NEMS. In this work, two main problems relating to the application of these carbon nanomaterials are addressed: synthesis (including nucleation and growth) and interface mechanical behavior. Firstly, we investigated the nucleation process of CNT caps on specific metal catalyst from both thermodynamic and kinetic perspective. Despite the minor effect of vertices of the metal catalyst on distribution of pentagons of caps, the main factor that determines the formation energy of caps is still the interface energy between cap edge and metal catalyst. Edge-etching “reverse engineering” reveals that the nucleation barrier maxima happens before complete matureness of caps, thus the possibility to control the chirality of synthesized CNT through cap-catalyst matching is subtle. Another issue that affects the production of CNTs is the growth speed. We utilized Markov chain theory to explain and analyze the phenomena such as growth speed, chirality change and the early termination due to emergence of defects during the growth stage. From the Markov chain theory we explored the effects of energy barrier, flux rate and temperature on the growth of CNTs. Two interface mechanical phenomena were investigated in the second part. It is disclosed that recoverable covalent cross links between CNTs or graphene sheets result in a nanoscale friction due to bond ruptures, which is logarithmically dependent on the shear rate and temperature. This friction plays an important role to strengthen CNT bundles or other composites. Oscillatory motion between bilayer graphene sheets was also explored through molecular dynamics (MD). The tunable gigahertz oscillator could be implemented into NEMS as nanooscillator. Another nanoscale friction in this system due to dissipation of kinetic energy to heat was investigated through both MD and theoretical analysis of adiabatic process, which is discovered to be linearly dependent on the motion velocity. These reveal that nanoscale friction is significantly different from macroscopic friction. | en_US |
| dc.format.mimetype | application/pdf | en_US |
| dc.identifier.citation | Luo, Ming. "Computational Modeling of Growth and Mechanical Behavior of Carbon-based Nanomaterials." (2018) Diss., Rice University. <a href="https://hdl.handle.net/1911/105547">https://hdl.handle.net/1911/105547</a>. | en_US |
| dc.identifier.uri | https://hdl.handle.net/1911/105547 | en_US |
| dc.language.iso | eng | en_US |
| dc.rights | Copyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder. | en_US |
| dc.subject | carbon nanomaterials | en_US |
| dc.subject | carbon nanotube | en_US |
| dc.subject | graphene | en_US |
| dc.subject | simulations | en_US |
| dc.subject | nucleation | en_US |
| dc.subject | growth | en_US |
| dc.subject | interface | en_US |
| dc.subject | mechanics | en_US |
| dc.title | Computational Modeling of Growth and Mechanical Behavior of Carbon-based Nanomaterials | en_US |
| dc.type | Thesis | en_US |
| dc.type.material | Text | en_US |
| thesis.degree.department | Materials Science and NanoEngineering | en_US |
| thesis.degree.discipline | Engineering | en_US |
| thesis.degree.grantor | Rice University | en_US |
| thesis.degree.level | Doctoral | en_US |
| thesis.degree.major | Computational Materials Science | en_US |
| thesis.degree.name | Doctor of Philosophy | en_US |
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