A joint density functional and classical molecular dynamics study on interface characteristics of graphene and polyetheretherketone

Sert, Elif
Graphene is a single layer allotrope of carbon with a honeycomb arrangement of atoms, characterized by excellent mechanical properties such as high tensile strength, high Young’s modulus as well as desirable electrical properties such as high electron mobility. Due to these superior properties, it is considered an important material in numerous technological applications. Among these, graphene-polymer composites have attracted significant interest in the materials research community in recent years. The use of these composites are particularly important in such fields as aeronautics where strength and low mass are simultaneously desirable. The testing, processing and construction of applicable mixtures of graphene and polymers pose challenges experimentally. Therefore, numerical modeling of graphene and graphene reinforced polymer composites is essential. The main purpose of this thesis is to study the properties of the interface between graphene and the Poly Ether Ether Ketone (PEEK) polymer within the Density Functional Theory (DFT) and Molecular Dynamics (MD) frameworks. PEEK is a high performing thermoplastic polymer with remarkable mechanical characteristics, chemv ical resistance, and relative high melting temperatures. We study the interaction from the smallest building units of a single monomer and build it up to 3-, 6- and 9-monomer chains, revealing all of its facets. In addition, we adhesion characteristics between graphene and PEEK oligomers as they slide past one another as a function of such important parameters as velocity, temperature and chain length.


A density functional theory study on the structural and electronic properties of PbxSbySez (x plus y plus z=2, 3) clusters
Pekoz, Rengin; Erkoç, Şakir (2018-01-30)
The structural and electronic properties of neutral ternary PbxSbySez clusters (x y + z = 2, 3) in their ground states have been explored by means of density functional theory calculations. The geometric structures and binding energies are systematically explored and for the most stable configurations of each cluster type vibrational frequencies, charges on atoms, energy difference between highest occupied and lowest unoccupied molecular orbitals, and the possible dissociations channels have been analyzed. ...
A density functional theory investigation of graphene-based materials
Sayın, Ceren Sibel; Toffoli, Hande; Department of Physics (2014)
Employability of graphene-based materials in various technological applications in order to exploit its exceptional properties is achieved/improved via their interactions with various atoms, molecules, nanostructures and surfaces. In this thesis, the interaction of cyclohexane and derived molecules, carbon nanotubes and metallic surfaces with both pristine and defected graphene structures are investigated using density functional theory.
A comparative study of the electronic properties of aluminum nitride compounds
Mohammad, Rezek; Katırcıoğlu, Şenay (2016-01-01)
Electronic properties of aluminum nitride in wurtzite, zinc-blende, and rock-salt phases are investigated by a full potential-linearized augmented plane waves method based on density functional theory within standard local density approximation and its four improved versions. Local density approximation corrected by the generalized gradient functional of Perdew-Wang-Engel-Vosko is found to be more successful than the other generalized gradient functional approximations considered in this work for providing ...
A theoretical study of chemical doping and width effect on zigzag graphene nanoribbons
Pekoz, Rengin; Erkoç, Şakir (Elsevier BV, 2009-12-01)
The energetics and the electronic properties of nitrogen- and boron-doped graphene nanoribbons with zigzag edges have been investigated using density functional theory calculations. For the optimized geometry configurations, vibrational frequency analysis and wavefunction stability tests have been carried out. Different doping site optimizations for a model nanoribbon have been performed and formation energy values of these sites revealed that zigzag edgesite for both of the dopants were the most favorable ...
Modeling of spherulite microstructures in semicrystalline polymers
Oktay, H. Emre; Gürses, Ercan (2015-11-01)
Semicrystalline polymers are composed of crystalline structures together with amorphous polymer chain networks and therefore they exhibit deformation mechanisms of both crystalline materials and amorphous polymers. One of the most common microstructures observed in semicrystalline polymers is the spherulite microstructure in which crystalline lamellae are embedded in a matrix of amorphous material and grow out from a common central nucleus in radial directions. The mechanical behavior of semicrystalline pol...
Citation Formats
E. Sert, “A joint density functional and classical molecular dynamics study on interface characteristics of graphene and polyetheretherketone,” M.S. - Master of Science, Middle East Technical University, 2020.