| 1. |
- Kavas, H., et al.
(författare)
-
Negative Permittivity of Polyaniline-Fe3O4 Nanocomposite
- 2013
-
Ingår i: Journal of Inorganic and Organometallic Polymers and Materials. - : Springer Science and Business Media LLC. - 1574-1443 .- 1574-1451. ; 23:2, s. 306-314
-
Tidskriftsartikel (refereegranskat)abstract
- Polyaniline-Fe3O4 nanocomposite with and without ionic liquid were successfully synthesized via in situ polymerization using cetyl trimethylammonium bromide (CTAB) as surfactant. Both TG analysis and FT-IR measurements proved the presence of organic layer on the surface of Fe3O4 nanoparticles. The influence of 1-butyl-3-methyl-imidazolium bromide (BMIMBr) as ionic liquid on the structure, conductivity, and magnetic property of PANI-Fe3O4-CTAB nanocomposite were studied in detail. The results show that imidazolium-based ionic liquids BMIMBr acts as an anchor agent during the formation of PANI-Fe3O4-CTAB nanocomposite. Ionic liquid significantly deteriorated nanocomposite's magnetic properties, and contributed to non-saturated M-H curve due to the disappearance of antiferromagnetic interactions. It has also an improving effect on AC and DC conductivities. The most important effect of IL is observed in real part of permittivity of PANI-Fe3O4-CTAB that it has negative high values at low frequency low temperature region. Due to the negative dielectric constant, material exhibits uncommon properties in electromagnetic waves scattering and attraction between similar charges. This possibility provokes research on these composites as high T superconductors, negative index materials and microwave absorbers.
|
|
| 2. |
- Akman, O., et al.
(författare)
-
Magnetic metal nanoparticles coated polyacrylonitrile textiles as microwave absorber
- 2013
-
Ingår i: Journal of Magnetism and Magnetic Materials. - : Elsevier BV. - 0304-8853 .- 1873-4766. ; 327, s. 151-158
-
Tidskriftsartikel (refereegranskat)abstract
- Polyacrylonitrile (PAN) textiles with 2 mm thickness are coated with magnetic nanoparticles in coating baths with Ni, Co and their alloys via an electroless metal deposition method. The crystal structure, morphology and magnetic nature of composites are investigated by X-ray Powder diffraction, Scanning Electron Microscopy, and dc magnetization measurement techniques. The frequency dependent microwave absorption measurements have been carried out in the frequency range of 12.4-18 GHz (X and P bands). Diamagnetic and ferromagnetic properties are also investigated. Finally, the microwave absorption of composites is found strongly dependent on the coating time. One absorption peak is observed between 14.3 and 15.8 GHz with an efficient absorption bandwidth of 3.3-4.1 GHz (under -20 dB reflection loss limit). The Reflection loss (RL) can be achieved between -30 and -50 dB. It was found that the RL is decreasing and absorption bandwidth is decreasing with increasing coating time. While absorption peak moves to lower frequencies in Ni coated PAN textile, it goes higher frequencies in Co coated ones. The Ni-Co alloy coated composites have fluctuating curve of absorption frequency with respect to coating time. These results encourage further development of magnetic nanoparticle coated textile absorbers for broadband applications.
|
|
