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| Author(s): |
Rafael Amatte Bizão
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Física Gleb Wataghin |
| Defense date: | 2017-11-10 |
| Examining board members: |
Douglas Soares Galvão;
Alexandre Fontes da Fonseca;
Kleber Roberto Pirota;
André Rodrigues Muniz;
Ricardo Paupitz Barbosa dos Santos
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| Advisor: | Douglas Soares Galvão |
| Abstract | |
Graphene is a recently isolated material made exclusively by carbon atoms that has low density, atomic thickness and excellent electronic, thermal, optical and mechanical properties. In this study, we employed classical molecular dynamics simulations to characterize the elasticity, mechanical strength, mechanical resistance due to impact and tribology of different graphene-based materials. In chapter 1, we started with a brief introduction to graphene, derivated its electronic properties using the tight binding method, described some graphene-based materials, the molecular dynamics method and some important definitions of mechanical properties. In chapter 2, we calculated the mechanical properties for a new graphene nanoribbons family known as nanowiggles. Our results show that, like its electronic properties, the mechanical properties of graphene nanowiggles also can be tuned according to its topology. In chapter 3, we analised the strength and energy absortion of graphene sheets under high impact ballistic tests. More specifically, we utilised an analytical model to relate results obtained theoretically at nano scale with experimental results obtained at micro scale. Thereby, we justified the difference of one order of magnitude obtained between theoretical and experimental studies and suggested that the best performance of graphene for this kind of application would be obtained for few layers. In chapter 4 we did molecular dynamics calculations for the tribology process performed by our collaborators. We utilised a silicon tip to study the friction with the step edge formed by the difference of height between one layer and two layers graphene. We found a transition from a stage in which the normal force is small, enabling the superior layer to bend and afterwards overcome the van der Waals force without breaking any bond, for another stage with higher normal force that slides the superior layer and hence break chemical bonds. In chapter 5 we show the resulting publications of my PhD project. Lastly, in chapter 6 we show the general conclusions of this study (AU) | |
| FAPESP's process: | 13/17468-5 - Design of Smart Surfaces With Tunable Wetting Behavior |
| Grantee: | Rafael Amatte Bizão |
| Support Opportunities: | Scholarships in Brazil - Doctorate |