Multiscale Simulations of Discotic Materials

Ziogos, Orestis George; Ζιώγος, Ορέστης Γεώργιος

dc.contributor.author	Ziogos, Orestis George	en
dc.contributor.author	Ζιώγος, Ορέστης Γεώργιος	el
dc.date.accessioned	2018-04-20T10:10:26Z
dc.date.available	2018-04-20T10:10:26Z
dc.date.issued	2018-04-20
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/46855
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.2923
dc.rights	Αναφορά Δημιουργού - Μη Εμπορική Χρήση - Παρόμοια Διανομή 3.0 Ελλάδα	*
dc.rights.uri	http://creativecommons.org/licenses/by-nc-sa/3.0/gr/	*
dc.subject	Δισκόμορφα υλικά	el
dc.subject	Νανογραφένιο	el
dc.subject	Οργανικά ηλεκτρονικά	el
dc.subject	Μοριακή Δυναμική	el
dc.subject	Θεωρία Συναρτησιακού Ηλεκτρονικής Πυκνότητας	el
dc.subject	Discotic materials	en
dc.subject	Nanographene	en
dc.subject	Organic electronics	en
dc.subject	Molecular Dynamics	en
dc.subject	Density Functional Theory	en
dc.title	Multiscale Simulations of Discotic Materials	en
dc.title	Προσομοιώσεις Πολλαπλής Κλίμακας Δισκόμορφων Υλικών	el
dc.contributor.department	Τομέας ΙΙΙ - Επιστήμης και Τεχνικής των Υλικών	el
heal.type	doctoralThesis
heal.classification	MATERIALS SCIENCE	en
heal.classification	PHYSICS	en
heal.classification	COMPUTATIONAL PHYSICS	en
heal.classificationURI	http://data.seab.gr/concepts/840868f9d668cd136ec6f074902084034906c943
heal.classificationURI	http://data.seab.gr/concepts/ac3478d69a3c81fa62e60f5c3696165a4e5e6ac4
heal.classificationURI	http://data.seab.gr/concepts/09e8c435d248d8bcc197638f445400edf42a8b80
heal.language	en
heal.access	free
heal.recordProvider	ntua	el
heal.publicationDate	2018-03-19
heal.abstract	Soluble disc-shaped organic molecules with the ability to self-organize into intricate supramolecular assemblies constitute a very promising materials family for a plethora of applications. In the case of polyaromatic hydrocarbon (PAH) mesogens, delocalized π interactions enable such materials to be used as active media for organic electronic applications. This doctoral dissertation is primarily focused on multiscale simulations of discotic materials by means of ab-initio Density Functional Theory (DFT) calculations and empirical Molecular Mechanics and Molecular Dynamics (MD) simulations for the determination of structure-property relationships, ranging from electronic and charge transfer properties at the quantum level of description to structural, mechanical, and dynamical characterization of periodic bulk systems at the nanoscale regime. As regards systems under study, molecules belonging to the so-called nanographene family are examined, with particular focus placed on the hexa-peri-hexabenzocoronene (HBC) molecule and its derivatives, utilizing a variety of peripheral functional groups. Quantum mechanical (QM) calculations are employed for the conduction of comparative studies involving molecules from the very smallest discotic unit, i.e. the benzene molecule, up to large polyaromatic assemblies, covalently-linked into forming articulate discotic “super-molecules”. Electronic and charge transfer properties are examined at the single molecule and molecular dimer levels of description via ground-state DFT calculations. Alkyl-substituted HBC derivatives, either in non-polar or polar variants by means of iodine atom peripheral functionalization, are examined through empirical MD simulations, aiming at the determination of structural, mechanical, and dynamical properties for given temperature and pressure conditions. PAH stacking patterns are thoroughly examined, a structural feature of paramount importance, since QM studies both in this work and in the literature confirm the direct link between charge transfer capabilities and core packing motifs. Amphiphilic, “Janus-type” HBC derivatives are also examined by means of MD simulations. Mesogens under study carry both hydrophilic and hydrophobic side chains, thus enabling the formation of lamellar molecular crystals. The effect of temperature rise on structural and dynamical properties is examined, while gaining an atomistic insight of the melting process for such materials. Atomistic MD simulations are also put to use for the examination of molecular crystals of functionalized extended discotics, namely the superphenalene C96 and the tetragonal C132 molecules, characterized by a 3-fold and 4-fold expanse, respectively, compared to HBC. Apart from single core discotics, covalently-linked assemblies in the form of the HBC dumbbell and star-shaped, tri-arm “super- molecules” with HBC, C96, and C132 terminal cores are modeled by means of MD simulations, elucidating their tendency to form structurally robust chiral molecular nanowires, densely packed into hexagonal molecular crystals. A multiscale methodology is adopted, using information from ab-initio DFT calculations, in order to provide insight for possible charge transfer mechanisms pertinent to such assemblies. As regards initial configurations to be used as input for atomistic simulations, in cases where crystallographic constructions are not applicable or desirable, a hybrid MC bond-by-bond growth methodology is proposed and utilized, capable of growing soft nanophases out of rigid nanostructured areas in a given simulation domain.	en
heal.sponsor	Ίδρυμα Κρατικών Υποτροφιών	el
heal.advisorName	Theodorou, Theodoros (Doros)	en
heal.committeeMemberName	Theodorou, Theodoros (Doros)	en
heal.committeeMemberName	Tsetseris, Leonidas	en
heal.committeeMemberName	Pissis, Polykarpos	en
heal.committeeMemberName	Floudas, George	en
heal.committeeMemberName	Charitidis, Costas	en
heal.committeeMemberName	Likos, Christos	en
heal.committeeMemberName	Harmandaris, Vaggelis	en
heal.academicPublisher	Σχολή Χημικών Μηχανικών	el
heal.academicPublisherID	ntua
heal.numberOfPages	235
heal.fullTextAvailability	true