StatusThe thesis was presented on the 24 June, 2016
Approved by NCAA on the 6 October, 2016
Abstract– 2.38 Mb / in romanian
12.65 Mb /
The thesis consists of introduction, four chapters, general conclusions and recommendations, 213 references, two annexes, 130 pages, 88 figures, 23 charts, eight tables. The results are published in 17 scientific publications (seven articles and 10 theses at conferences).
Field of study: Nature Sciences
The aim and the objectives of the thesis: The study falls under the field of inorganic nanomaterials and aims at obtaining iron oxides and mixed oxides through chemical processes, starting from homo- and heteronuclear iron clusters. In order to do this, the following targets were set: synthesis of homo- and heteronuclear clusters of iron as metal precursors for nanoparticles; preparation of nanoparticles from preformed clusters by adapting established methods or by unconventional methods; optimization of the methods for obtaining iron oxides nanoparticles with preset sizes and shapes; characterization of the nanoparticles obtained by using various methods; identifying potential applications of the obtained nanoparticles.
Novelty and relevance of the study consists in the use of the iron mixed valence clusters and of the heteronuclear iron-chromium clusters as precursors for nanoparticles with predetermined structure and chemical composition. Stabilization of the nanoparticles was achieved by hydrophobic treatment with organic surfactants. It was highlighted and reported for the first time in the literature the self-assembly of organic phase in the presence of inorganic core (metal oxide) in a phase with a high degree of ordering (smectic crystal), which is useful for optical applications. Also, for the first time, silicone surfactant was used for hydrophobic – hydrophilic conversion treatment of the iron oxide nanoparticles surface. An iron complex with a newly synthesized macromolecular ligand containing siloxane segments generated iron oxide nanoparticles covered with silica through thermal decomposition.
Scientific problem solved in this thesis: Optimal processes were established for obtaining iron oxide and mixed oxides nanoparticles with preset structure, shape and size by using suitable precursors.
The theoretical importance and potential application value of the work: The thesis contributes to the understanding of the process for preparation of metal oxides nanoparticles. It has been shown that by using heteronuclear clusters could be obtained nanoparticles with the same ratio of metals as the starting cluster. The applicative importance of the thesis consists in the possibility of using the procedures that were developed for the synthesis of iron oxide nanoparticles in the preparation of new materials.
Implementation of scientific results: It was demonstrated the possibility of co-encapsulating hydrophobic drugs inside systems consisting of superparamagnetic nanoparticles - silicone surfactants, which makes them attractive for applications such as targeted drug delivery inside the human body. Also, using α-Fe2O3 nanoparticles as filler for silicones elastomers leads to increased dielectric permitivity.
Under consideration  :