| 1. |
- Aydin, M., et al.
(författare)
-
Synthesis and characterization of poly(3-thiophene acetic acid)/Fe3O4 nanocomposite
- 2011
-
Ingår i: Polyhedron. - : Elsevier BV. - 0277-5387 .- 1873-3719. ; 30:6, s. 1120-1126
-
Tidskriftsartikel (refereegranskat)abstract
- Poly(3-thiophene acetic acid)/Fe3O4 nanocomposite is synthesized by the precipitation of Fe3O4 in the presence of poly(3-thiophene acetic acid) (P3TAA). Structural, surface, morphological, thermal properties and conductivity characterization/evaluation of the nanocomposite were performed by XRD, FT-IR, TEM, TGA. and conductivity measurements, respectively. The capping of P3TAA around Fe3O4 nanoparticles was confirmed by FT-IR spectroscopy, the interaction being via bridging oxygens of the carboxylate and the nanoparticle surface through bidentate binding. The crystallite and particle size were obtained as 9 +/- 2 nm and 11 +/- 1 nm from XRD line profile fitting and TEM image analysis, respectively, which reveal nearly single crystalline nature of Fe3O4 nanoparticles. Magnetization measurements reveal that P3TAA coated magnetite particles do not saturate at higher fields. There is no coercivity and remanence revealing superparamagnetic character. Magnetic particle size calculated from the theoretical fitting as 9.1 nm which coincides the values determined from TEM micrographs and XRD line profile fitting. The comparison to the TEM particle size reveals slightly modified magnetically dead nanoparticle surface.
|
|
| 2. |
- Durmus, Z., et al.
(författare)
-
Synthesis and characterization of L-carnosine coated iron oxide nanoparticles
- 2011
-
Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 509:5, s. 2555-2561
-
Tidskriftsartikel (refereegranskat)abstract
- L-Carnosine coated iron oxide nanoparticles (CCIO NPs) have been prepared via co-precipitation of iron oxide in the presence of L-carnosine. Crystalline phase was identified as magnetite with an average crystallite size of 8 nm as estimated from X-ray line profile fitting. Particle size estimated from TEM by log-normal fitting was similar to 11 nm. FTIR analysis showed that the binding of carnosine onto the surface of iron oxide is through unidentate linkage of carboxyl group. CCIO NPs showed superparamagnetic charactersitic at room temperature. The magnetic core size of superparamagnetic CCIO NPs was found slightly smaller than the size obtained from TEM, due to the presence of magnetically dead layer. Magnetization measurements revealed that L-carnosine iron oxide composite has immeasurable coercivity and remanence with absence of hysteritic behavior, which implies superparamagnetic behavior at room temperature. The low value of saturation magnetization compared to the bulk magnetite has been explained by spin canting. LDH activity tests showed slight cytotoxicity of high dose of CCIO NPs. The ac conductivity of CCIO NPs was found to be greater than that of carnosine and the effective conduction mechanism was found as correlated barrier hopping (CBH). dc activation energy of the product at around room temperature was measured as 0.312 eV which was in good agreement with the earlier reports.
|
|
| 3. |
- Karaoglu, E., et al.
(författare)
-
Effect of Hydrolyzing Agents on the Properties of Poly (Ethylene Glycol)-Fe3O4 Nanocomposie
- 2011
-
Ingår i: Nano-Micro Letters. - 2150-5551. ; 3:2, s. 79-85
-
Tidskriftsartikel (refereegranskat)abstract
- Poly (ethylene glycol) (PEG) assisted hydrothermal route has been used to study the influence of the hydrolyzing agent on the properties of PEG-iron oxide (Fe3O4) nanocomposites. Iron oxide nanoparticles (NPs), as confirmed by X-ray diffraction analysis, have been synthesized by a hydrothermal method in which NaOH and NH3 were used as hydrolyzing agents. Formation of PEG-Fe3O4 nanocomposite was confirmed by Fourier transform infrared spectroscopy (FTIR). Samples exhibit different crystallite sizes, which estimated based on line profile fitting as 10 nm for NH3 and 8 nm for NaOH hydrolyzed samples. The average particle sizes obtained from transmission electron microscopy was respectively 174 +/- 3 nm for NaOH and 165 +/- 4 nm for NH3 gas hydrolyzed samples. Magnetic characterization results reveal superparamagnetic characteristics despite a large particle size, which indicate the absence of coupling between the nanocrystals due to the presence of polymer in the nanocomposites. The conductivity curve demonstrates that sigma(DC) is strongly temperature dependent.
|
|
