New hybrid functional materials based on carbon (Doctoral thesis)

Ζυγούρη, Παναγιώτα

The aim of this PhD thesis was to synthesize and develop novel hybrid functional materials based on graphite and fullerenes, to study their properties and to investigate their use in various applications on these properties. Chapter 3 constitutes an overview of various theoretical and experimental studies about the interactions of polyaromatic hydrocarbons (PAHs) with graphene sheets. In these works efforts were made to clarify the role of PAHs in the development of new composites for a plenty of applications such as in electronic, sensing and biomedical devices. Because PAHs and their metabolites are mutagenic and carcinogenic, most of the studies focused on the elimination of PAHs’ toxicity with the help of nanomaterials, e.g. based on graphene. In chapter 4 we present for the first time the successful chemical oxidation of buckminsterfullerene (C60) based on the well-known Staudenmaier method, producing what is called oxidized fullerenes. This facile and reproducible approach creates oxygen functional groups, like epoxy and hydroxyl groups on the surface of the fullerene, which make this material highly soluble in polar solvents such as water. An important advantage of this method consists in the presence of epoxy groups that allow for further functionalization. In this thesis, oxidized fullerenes were modified with a primary aliphatic amine (octadecylamine) thus generating a new fullerene derivative. The hydrophilic character of these materials potentially renders them ideal for a plethora of applications, for example in medicinal chemistry and biochemistry. Chapter 5 describes the chemical oxidation of carbon nanodiscs (oxCNDs), which were industrially produced via the so-called pyrolytic Kværner Carbon Black & H2 process. The facile, versatile and reproducible oxidation procedure was based on the Staudenmaier method. The result of the oxidation treatment was firstly the separation of carbon nanodiscs from the mixed nanodiscs/nanocones/soot starting material and secondly the attachment of oxygen-containing functional groups (epoxy, hydroxyl and carboxyl groups) on their surface, improving their solubility in polar solvents (e.g. water). The obtained material was characterized by many characterization techniques, which confirmed the successful oxidation and provided information about the morphology. The investigation their potential for bioapplications demonstrated that oxidized nanodiscs can act as cytotoxic agent and as supports for nanobiocatalytic systems. Chapter 6 we report the intercalation of Ibuprofen, a nonsteroidal anti-inflammatory drug, into graphite oxide and into two its derivatives, namely sulfonated and carboxylated graphene oxide. The aim of this project was to study the efficacy of these three nanomaterials as delivery systems of Ibuprofen. The adsorption of the drug into carbon carriers was quantified and the release of Ibuprofen in simulated gastric and intestinal fluid determined. The results show that the release in gastric fluid takes place more gradually than in intestinal fluid and promise well for these nanomaterials’ potential to eliminate the drug’s side effects in the stomach. Chapter 7 gives an overview of four published studies. More specifically, we describe in detail the electrical conductivity, as a function of temperature of different fullerene derivatives. For this purpose, polybrominated fullerenes (C60Br6), polyhydroxylated fullerenes [C60(OH)24] and sodium fullerene salt (C60O24Na24) were synthesized and studied.
Alternative title / Subtitle: σύνθεση, χαρακτηρισμός και μελέτη ιδιοτήτων
synthesis, characterization and study of properties
Institution and School/Department of submitter: Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Μηχανικών Επιστήμης Υλικών
Subject classification: Carbon
Keywords: Οξειδωμένα φουλερένια,Νανοδίσκοι άνθρακα,Οξείδιο του γραφενίου,Σύστημα μεταφοράς φαρμάκου,Oxidized fullerenes,Carbon nanodiscs,Graphene oxide,Drug delivery system
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