Here, we report on the synthesis of PEG-Mn_3O_4 nanocomposite(NP's) via a hydrothermal route by using Mn(acac)2, ethanol, NH3 and PEG-400. The crystalline phase was identified as Mn_3O_4. The crystallite size of t...Here, we report on the synthesis of PEG-Mn_3O_4 nanocomposite(NP's) via a hydrothermal route by using Mn(acac)2, ethanol, NH3 and PEG-400. The crystalline phase was identified as Mn_3O_4. The crystallite size of the PEG-Mn_3O_4 nanocomposite was calculated as 12±5 nm from X-ray line profile fitting and the average particle size from TEM was obtained as 200 nm. This reveals polycrystalline character of Mn_3O_4 NP's. The interaction between PEG-400 and the Mn_3O_4 NP's was investigated by FTIR. Temperature independent AC conductivity of PEG-Mn_3O_4 nanocomposite beyond 20 k Hz 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. Above that temperature, Mn_3O_4 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 e V) 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. 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 k Hz for 20 while the maximum was detected at 23.2 k Hz for 90.展开更多
基金the Fatih University,Research Project Foundation(Contract No.:P50020902-2)Turkish Ministry of Industry and TUBITAK(Contract No.:110T487)for financial support of this study
文摘Here, we report on the synthesis of PEG-Mn_3O_4 nanocomposite(NP's) via a hydrothermal route by using Mn(acac)2, ethanol, NH3 and PEG-400. The crystalline phase was identified as Mn_3O_4. The crystallite size of the PEG-Mn_3O_4 nanocomposite was calculated as 12±5 nm from X-ray line profile fitting and the average particle size from TEM was obtained as 200 nm. This reveals polycrystalline character of Mn_3O_4 NP's. The interaction between PEG-400 and the Mn_3O_4 NP's was investigated by FTIR. Temperature independent AC conductivity of PEG-Mn_3O_4 nanocomposite beyond 20 k Hz 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. Above that temperature, Mn_3O_4 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 e V) 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. 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 k Hz for 20 while the maximum was detected at 23.2 k Hz for 90.
