Optičke i transportne osobine nanoprahova na bazi oksida gvožđa
Optical and transport properties of iron oxide nanoparticles
Author
Mamula Tartalja, DanicaMentor
Milanović, VitomirCommittee members
Ivanović, Nenad
Radovanović, Jelena

Raković, Dejan

Radunović, Jovan


Metadata
Show full item recordAbstract
Electrical Engineering / Physical Electronics
Nanočestice oksida gvođža, posebno magnetita (Fe3O4), privlače pažnju zbog svojih
superparamagnetnih osobina, biokompatibilnosti i niskog nivoa toksičnosti. Od mnoštva
metoda za dobijanje nanočestica, elektrohemijska (EH) metoda se pokazala kao
jednostavna, jeftina i ekološki prihvatljiva, a pored toga omogućava i dobru kontrolu
osobina dobijenih čestica. Struktura, morfologija i veličina čestica, pa time i njihove
magnetne, optičke i električne osobine, mogu se menjati promenom uslova u EH ćeliji
tokom procesa sinteze i/ili njihovim naknadnim grejanjem u odgovarajućoj atmosferi.
U ovoj disertaciji ispitivane su mogućnosti sinteze nanoprahova oksida gvožđa, EH
metodom, u opsegu gustina struje J = 200-1000 mA/dm2 i temperatura T = 295-361 K.
Takođe je proučeno preuređenje katjona i vakancija u magnetitu, prouzrokovano
toplotom, kao i fazni prelazi magnetit-maghemit (γ-Fe2O3) i maghemit-hematit (α-Fe2O3).
U disertaciji su prikazani rezultati ispitivanja strukture, morfologije i raspodele... veličine
čestica dobijenih nanoprahova, koji su dobijeni različitim tehnikama, kao što su difrakcija X-zračenja (XRD), skenirajuća i transmisiona elektronska mikroskopija (SEM, TEM) i
dinamičko rasejanje laserske svetlosti. Magnetne osobine su određene merenjem
zavisnosti magnetizacije od temperature Faradejevom metodom i merenjem histerezisa
SQUID aparaturom.Izmereni su i infracrveni (IC) sprektri dobijenih prahova, kao i
temperaturna zavisnost specifične električne otpornosti i specifične toplote.
Da bi se ispitali načini vezivanja različitih organskih supstanci, koje se često koriste za
oblaganje nanočestica oksida gvožđa, ravnotežne konformacije i vibracioni spektri
molekula limunske kiseline, dekstrana (1-5 molekula), polietilen glikola (1-3 molekula),
citozana (1-3 molecula) i oleinske kiseline proračunati su polu-empirijskom,
kvantno-mehaničkom metodom AM1, a neki od molekula i metodom linearne
kombinacija atomskih orbitala (LCAO), sa bazisom talasnih funkcija 631-G,
korišćenjem programskog paketa HyperChem. Mogućnosti primene dobijenih nanoprahova oksida gvožđa u biosistemima, ispitane su
tako što su neki neobloženi, kao i neki prahovi obloženi limunskom kiselinom (ferofluid),
u različitim koncentracijama parenteralno administrirani Wistar pacovima in vivo, ili
primenjeni na uzorke humane krvi, in vitro. 24 časa posle primene nanoprahova i
ferofluida, analizirane su promene krvne slike, diferencijalne krvne slike, i ispitane metabolčke promene, pomoću VSC (Volume-Conductivity-Light Scatter) aparature.
Utvrđeno je da primenjeni nanoprahovi i ferofluid na različite načine utiču na krv, ali da u primenjenim koncentracijama nisu štetni, ni na koji način.
Iron oxide nanoparticles, especially Magnetite (Fe3O4), have attracted attention due to
their biocompatibility, low toxicity and superparamagnetic properties. Among the
numerous methods for nanoparticles preparation, the electrochemical (EH) method has
been recognised as an easily feasible, low cost, and environmental friendly preparation
process, which offers good possibillity for nanoparticles properties control. Structure,
morphology, size, magnetic, optical, and electrical properties of the powders can be tuned
by changing the conditions in the EH cell during the powder synthesis, and/or by their
subsequent heating in the appropriate atmosphere.In this dissertation, the EH synthesis of iron oxide nanopowders of specific
characteristics is investigated in the range of current density of J = 200–1000 mA/dm2,
and temperature of T = 295–361 K. The temperature induced cation-vacancy reordering
in magnetite, the magnetite to maghemite (γ-Fe2O3), and the maghemite to haematite (α-
Fe2O3) ...phase transitions were examined, as well. For that reason structure, morphology
and particle size distribution of the produced powders are investigated, using X-ray
diffraction (XRD), Scanning and Transmition Electron Microscopy (SEM and TEM), and
dynamic light scattering. The magnetic properties are established by temperature
dependent magnetisation measurements using Faraday method, and hysteresis
measurements by SQUID. Infrared spectra and temperature dependences of specific
electrical resistivity and specific heat are also determined.In order to analyse the attachment of various surfactants, the properties of optimal
ground-state conformation, and vibrational spectra of citric acid molecule, dextran (1-5
molecules), polyethylen glicol (1-3 molecules), chitosan (1-3 molecules), and oleic acid
molecule are calculated at AM1 quantum-mechanical, and some of the molecules also at ab-initio LCAO (Linear Combination of Atomic Orbitals) 631-G level, using the HyperChem program package. The calculated results are compared with measured IR
spectra, and some literature data.
For the purpose of investigation of their applicability in biosystems, some of the obtained
powders were covered with the citric acid layer (ferrofluid), and together with some noncovered
powders parenterally administrated to Wistar rats in vivo, and human blood in
vitro in various concentrations. 24 hours after the application of the powders and the
ferrofluid, a Volume-Conductivity-Light Scatter apparatus is used to analyse the changes
of blood test, differential blood test, and metabolic changes. It has been established that
ferrofluid and plane powders influence blood in various ways, but that any of them is by
no means harmful in the applied concentrations