Hydrothermal Synthesis and Characterization of PEG-Mn3O4 Nanocomposite

Karaoglu E., Deligoz H., Sozeri H., Baykal A., Toprak M. S.

NANO-MICRO LETTERS, vol.3, no.1, pp.25-33, 2011 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 3 Issue: 1
  • Publication Date: 2011
  • Doi Number: 10.3786/nml.v3i1.p25-33
  • Journal Name: NANO-MICRO LETTERS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.25-33
  • Istanbul University Affiliated: Yes

Abstract

Here, we reported on the synthesis of PEG-Mn3O4 nanocomposite (NP’s) via a hydrothermal route by using Mn (acac)2, ethanol, NH3 and PEG-400. The crystalline phase was identi?ed as Mn3O4. The crystallite size of the PEG-Mn3O4 nanocomposite was calculated as 12 ± 5 nm from X-ray line pro?le ?tting and the average particle size from TEM was obtained as 200 nm. This reveals polycrystalline character of Mn3O4 NP’s. The interaction between PEG-400 and the Mn3O4 NP’s was investigated by FTIR. Temperature independent AC conductivity of PEG-Mn3O4 nanocomposite beyond 20 kHz provides a strong evidence of ionic conduction through the structure. The conductivity and permittivity measurements strongly depend on the secondary thermal transition of nanocomposite beyond 100°C. Above that temperature, Mn3O4 particles may interact with each other yielding a percolated path that will facilitate the conduction. On the other hand, the relatively lower activation energy (Ea=0.172 eV) for relaxation process suggests that polymer segmental motions of PEG and electrons hopping between Mn2+ and Mn3+ may be coupled in the sample below 100°C. Room temperature magnetization curve of the sample does not reach to a saturation, which indicates the superparamagnetic character of the particles. As the temperature increases, the frequency at which (ε'') reaches a maximum shifted towards higher frequencies. The maximum peak was observed at 1.4 kHz for 20°C while the maximum was detected at 23.2 kHz for 90°C.

Here, we report on the synthesis of PEG-5/Mn3O4 nanocomposite (NP's) via a hydrothermal route by using Mn(acac)(2), ethanol, NH3 and PEG-400. The crystalline phase was identified as Mn3O4. The crystallite size of the PEG-Mn3O4 nanocomposite was calculated as 12 +/- 5 urn from X-ray line profile fitting and the average particle size from TEM was obtained as 200 nm. This reveals polycrystalline character of Mn3O4 NP's. The interaction between PEG-400 and the Mn3O4 NP's was investigated by FTIR. Temperature independent AC conductivity of PEG-Mn3O4 nanocomposite beyond 20 kHz provides a strong evidence of ionic conduction through the structure. The conductivity and permittivity measurements strongly depend on the secondary thermal transition of nanocomposite beyond 100 degrees C. Above that temperature, Mn3O4 particles may interact with each other yielding a percolated path that will facilitate the conduction. On the other hand, the relatively lower activation energy (E-a=0.172 eV) for relaxation process suggests that polymer segmental motions of PEG and electrons hopping between Mn2+ and Mn3+ may be coupled in the sample below 100 degrees C. Room temperature magnetization curve of the sample does not reach to a saturation, which indicates the superparamagnetic character of the particles. As the temperature increases, the frequency at which (epsilon '') reaches a maximum shifted towards higher frequencies. The maximum peak was observed at 1.4 kHz for 20 degrees C while the maximum was detected at 23.2 kHz for 90 degrees C.