Polyol-vermittelte Präparation nanoskaliger Oxidpartikel

Feldmann, Claus; Jungk, Hans-Otto

doi:10.1002/1521-3757(20010119)113:2<372::aid-ange372>3.0.co;2-j

Cited by 46 publications

(18 citation statements)

References 32 publications

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“…Consequently, metal oxides are obtained at lower temperatures (e.g., 100–180 °C) and elemental metals at higher temperatures (180–250 °C). Typical systems with temperature‐dependent product composition are, for instance, Cu +II O/Cu +I 2 O/Cu 0 , Co +II O/Co 0 or Bi +III 2 O 3 /Bi 0 . Due to high temperature (partly close to the decomposition temperature of the polyols) and oxidation (polyols are oxidized upon reduction of metals), the polyols start to decompose (including dehydration, oxidation, decarboxylation, polymerization).…”

Section: Introductionmentioning

confidence: 99%

Unexpected Fluorescence of Polyols and PEGylated Nanoparticles Derived from Carbon Dot Formation

Dong

Roming

Feldmann

2014

Part. Part. Syst. Charact.

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Synthesis of nanoparticles in high‐boiling alcohols (so‐called polyol synthesis) and surface functionalization of nanoparticles with polyethylene glycol (so‐called PEGylation) in combination with certain heating are often accompanied with an intense fluorescence in the blue to green spectral range. Based on the polyol synthesis of Zn3(PO4)2 nanoparticles and a critical consideration of the relevant experimental conditions—including the presence of nanoparticles, the role of dissolved metal salts (ZnCl2, MgCl2, KCl), the type of the polyol (DEG, GLY, PEG400), the temperature and time of heating (150–230 °C, 1–6 h)—we can correlate the observed fluorescence to the formation of carbon dots (C‐dots) stemming from thermal decomposition (i.e., dehydration and carbonization) of the polyol. Thus, the thermal decomposition of polyols results in C‐dots with a diameter of 3–5 nm at narrow size distribution. The formation of C‐dots is confirmed by transmission electron microscopy (TEM), high‐resolution TEM (HRTEM), X‐ray powder diffraction (XRD), Fourier‐transform infrared spectroscopy (FT‐IR), and fluorescence spectra.

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Section: Introductionmentioning

confidence: 99%

Unexpected Fluorescence of Polyols and PEGylated Nanoparticles Derived from Carbon Dot Formation

Dong

Roming

Feldmann

2014

Part. Part. Syst. Charact.

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“…Polyol process [7][8][9] is a versatile chemical approach, which refers to the use of polyols (for example ethylene glycol, diethylene glycol, ethylene glycol) to reduce metal salts to metal particles, that has successfully been used to prepare a great variety of inorganic compounds nonaggregated particles. Triethylene glycol (TREG) with the general formula H(OCH 2 CH 2 ) n OH is a typical non-toxic, non-immunogenic, non-antigenic and protein resistant polymer, which is widely used in the pharmaceutical field, has attracted much attention.…”

Section: Introductionmentioning

confidence: 99%

Triethylene Glycol Stabilized CoFe2O4 Nanoparticles

Baykal

Deligöz

Sözeri

et al. 2012

J Supercond Nov Magn

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We report on the synthesis and detailed composition, thermal, micro-structural, ac-dc conductivity performance and dielectric permittivity characterization of triethylene glycol (TREG) stabilized CoFe 2 O 4 nanoparticles synthesized by polyol method. XRD analysis confirmed the inorganic phase as CoFe 2 O 4 with high phase purity. Microstructure analysis with TEM revealed well separated, spherical nanoparticles in the order of 6 nm, which is also confirmed by X-ray line profile fitting. FT-IR analysis confirms that TREG is successfully coated on the surface of nanoparticles. Overall conductivity of nanocomposite is approximately two magnitudes lower than that of TREG with increase in temperature. The ac conductivity showed a temperature dependent behavior at low frequencies and temperature independent behavior at high frequencies which is an indication of ionic conductivity. The dc conductivity of the nanocomposites and pure TREG are found to obey the Ar-A. Baykal ( ) · Z. Durmus rhenius plot with dc activation energies of 0.258 eV and 0.132 eV, respectively. Analysis of dielectric permittivity functions suggests that ionic and polymer segmental motions are strongly coupled in the nanocomposite. TREG stabilized CoFe 2 O 4 nanoparticles has lower ε and ε than that of pure TREG due to the doping of cobalt. As the temperature increases, the frequency at which (ε ) reaches a maximum shifted towards higher frequencies. On the other hand, the activation energy of TREG for relaxation process was found to be 0.952 eV which indicates the predominance of electronic conduction due to the chemical nature of TREG. Contrarily, no maximum peak of tan δ was observed for the nanocomposite due to the being out of temperature and frequency range applied in the study.

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“…This method, generally called the polyol method, has been successfully used for preparing a large variety of materials including oxides, phosphates [13], sulfides [14] and elemental metals [15,16]. For preparation of rare-earth based sesqui-oxides the choice of the precursors is quite crucial.…”

Section: Introductionmentioning

confidence: 99%