EXPERIMENTAL AND COMPUTATIONAL STUDY OF TUNABLE 2-DIMENSIONAL GROUP-III ALLOYS AND CARBON FIBERS
Open Access
- Author:
- Rajabpour, Siavash
- Graduate Program:
- Chemical Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- December 16, 2021
- Committee Members:
- Mauricio Terrones, Outside Unit Member
Joshua Robinson, Co-Chair, Outside Field Member & Dissertation Advisor
Raymond Schaak, Major Field Member
Michael Janik, Major Field Member
Adri van Duin, Co-Chair & Dissertation Advisor
Seong H. Kim, Professor in Charge/Director of Graduate Studies - Keywords:
- 2D Materials
Intercalation
Carbon Fibers
ReaxFF - Abstract:
- This dissertation has two distinct research foci: Carbon fibers and 2-Dimensional materials. As such, this abstract describes these separately. Carbon fibers (CFs), composed of 92 to 100 weight % (wt %) anisotropic carbon, are typically manufactured through a series of controlled thermal treatments of precursor polymer fibers. As connected and automated vehicles (CAVs) have been reshaping the transportation sector, there is a growing desire to capitalize on this opportunity to enhance fuel efficiency and reduce emissions by replacing metal components with light-weight, low-cost CF-reinforced composites. However, over 50% of their cost is attributed to the PAN precursor, a drawback that has triggered the search for low-cost alternatives. The work presented in this dissertation explores the strategy of improving the low-grade CFs properties by the graphene inclusion into the polymer matrix. Specifically, this dissertation presents studies regarding implementing ReaxFF molecular dynamic simulations to investigate the effects of graphene inclusion on CFs mechanical properties. The other research focus of this dissertation is atomically-thin, or 2-dimensional (2D) materials beyond van der Waals materials. 2D materials have gained tremendous interest in a wide range of scientific communities due to fundamental research afforded by single or few-atom-thick materials, as well as the potential for impact and application in electronic, optical, sensing, and quantum technologies. This dissertation presents investigation on stabilizing 2D group-III alloys with tunable properties via an intercalation process called Confinement Heteroepitaxy (CHet). These alloys exhibit tunable electronic and optical properties. This thesis is broken up into two main sections. First, after a short introduction on carbon fibers and 2-Dimensional materials (Chapter 1), Chapter 2 investigates how graphene inclusion into polymer matrix affect the chemistry and mechanical properties of low-grade carbon fibers. Chapter 3 introduces Confinement Heteroepitaxy (CHet) as a novel synthesis platform to stabilize group-III alloys with tunable electronic and photonic properties. We demonstrate that the electronic, superconducting and optical properties of air-stable two-dimensional metals can be controllably tuned by the formation of alloys. Chapter 4 introduces two ReaxFF force fields (GaCH-2020 and InCH-2020) which can be used to simulate the interaction of group-III metals with graphene. These force fields enable the investigation of intercalation mechanism in CHet and this knowledge can be used to extend the library of materials which can be stabilized by CHet. Chapter 5 will present ongoing and future work with a summary of findings in this thesis.