Abstract
Iron oxide magnetic nano-particles (MNPs) have been prepared in aqueous solution by a modified co-precipitation method. Surface modifications have been carried out using tetraethoxysilane (TEOS), triethoxysilane (TES) and 3-aminopropyltrimethoxysilane (APTMS). The uncoated and coated particle products have been characterized with transmission electron microscope (TEM), energy dispersive X-ray (EDX) spectroscopy, infrared (IR) and Raman spectroscopy, and thermal gravimetric analysis (TGA). The particle sizes were determined from TEM images and found to have mean diameters of 13, 16 and 14 nm for Fe{sub 3}O{sub 4}, TES/Fe{sub 3}O{sub 4} and APTMS/Fe{sub 3}O{sub 4}, respectively. IR and Raman spectroscopy has been applied to study the effect of thermal annealing on the uncoated and coated particles. The results have shown that magnetite nano-particles are converted to maghemite at 109 Degree-Sign C and then to hematite by 500 Degree-Sign C. In contrast, the study of the effect of thermal annealing of micro-crystalline magnetite by IR spectroscopy revealed that the conversion to hematite began by 300 Degree-Sign C and that no maghemite could be identified as an intermediate phase. IR spectra and TGA measurements revealed that the Si-H and 3-aminopropyl functional groups in TES and APTMS coated magnetite nano-particles decomposed below 500 Degree-Sign C while the silica
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Li Yingsing, E-mail: yingli@memphis.edu;
[1]
Church, Jeffrey S;
Woodhead, Andrea L
[2]
- Department of Chemistry, University of Memphis, Memphis, TN 38152 (United States)
- CSIRO Materials Science and Engineering, PO Box 21, Belmont, VIC 3216 (Australia)
Citation Formats
Li Yingsing, E-mail: yingli@memphis.edu, Church, Jeffrey S, and Woodhead, Andrea L.
Infrared and Raman spectroscopic studies on iron oxide magnetic nano-particles and their surface modifications.
Netherlands: N. p.,
2012.
Web.
doi:10.1016/J.JMMM.2011.11.065.
Li Yingsing, E-mail: yingli@memphis.edu, Church, Jeffrey S, & Woodhead, Andrea L.
Infrared and Raman spectroscopic studies on iron oxide magnetic nano-particles and their surface modifications.
Netherlands.
https://doi.org/10.1016/J.JMMM.2011.11.065
Li Yingsing, E-mail: yingli@memphis.edu, Church, Jeffrey S, and Woodhead, Andrea L.
2012.
"Infrared and Raman spectroscopic studies on iron oxide magnetic nano-particles and their surface modifications."
Netherlands.
https://doi.org/10.1016/J.JMMM.2011.11.065.
@misc{etde_22010761,
title = {Infrared and Raman spectroscopic studies on iron oxide magnetic nano-particles and their surface modifications}
author = {Li Yingsing, E-mail: yingli@memphis.edu, Church, Jeffrey S, and Woodhead, Andrea L}
abstractNote = {Iron oxide magnetic nano-particles (MNPs) have been prepared in aqueous solution by a modified co-precipitation method. Surface modifications have been carried out using tetraethoxysilane (TEOS), triethoxysilane (TES) and 3-aminopropyltrimethoxysilane (APTMS). The uncoated and coated particle products have been characterized with transmission electron microscope (TEM), energy dispersive X-ray (EDX) spectroscopy, infrared (IR) and Raman spectroscopy, and thermal gravimetric analysis (TGA). The particle sizes were determined from TEM images and found to have mean diameters of 13, 16 and 14 nm for Fe{sub 3}O{sub 4}, TES/Fe{sub 3}O{sub 4} and APTMS/Fe{sub 3}O{sub 4}, respectively. IR and Raman spectroscopy has been applied to study the effect of thermal annealing on the uncoated and coated particles. The results have shown that magnetite nano-particles are converted to maghemite at 109 Degree-Sign C and then to hematite by 500 Degree-Sign C. In contrast, the study of the effect of thermal annealing of micro-crystalline magnetite by IR spectroscopy revealed that the conversion to hematite began by 300 Degree-Sign C and that no maghemite could be identified as an intermediate phase. IR spectra and TGA measurements revealed that the Si-H and 3-aminopropyl functional groups in TES and APTMS coated magnetite nano-particles decomposed below 500 Degree-Sign C while the silica layer around the iron oxide core remained unchanged. The molecular ratio of APTMS coating to iron oxide core was determined to be 1:7 from the TGA data. Raman scattering signals have indicated that MNPs could be converted to maghemite and then to hematite using increasing power of laser irradiation in a manner similar to that observed for thermal annealing. - Highlights: Black-Right-Pointing-Pointer A modified co-precipitation method to prepare dispersive iron oxide magnetic nano-particles. Black-Right-Pointing-Pointer Coating the nano-particle with different silicas. Black-Right-Pointing-Pointer Estimating the numbers of iron oxide and 3-aminopropylsilica in the coated particles. Black-Right-Pointing-Pointer Silica coating may help to protect iron oxide nano-particles from thermal transformation.}
doi = {10.1016/J.JMMM.2011.11.065}
journal = []
issue = {8}
volume = {324}
journal type = {AC}
place = {Netherlands}
year = {2012}
month = {Apr}
}
title = {Infrared and Raman spectroscopic studies on iron oxide magnetic nano-particles and their surface modifications}
author = {Li Yingsing, E-mail: yingli@memphis.edu, Church, Jeffrey S, and Woodhead, Andrea L}
abstractNote = {Iron oxide magnetic nano-particles (MNPs) have been prepared in aqueous solution by a modified co-precipitation method. Surface modifications have been carried out using tetraethoxysilane (TEOS), triethoxysilane (TES) and 3-aminopropyltrimethoxysilane (APTMS). The uncoated and coated particle products have been characterized with transmission electron microscope (TEM), energy dispersive X-ray (EDX) spectroscopy, infrared (IR) and Raman spectroscopy, and thermal gravimetric analysis (TGA). The particle sizes were determined from TEM images and found to have mean diameters of 13, 16 and 14 nm for Fe{sub 3}O{sub 4}, TES/Fe{sub 3}O{sub 4} and APTMS/Fe{sub 3}O{sub 4}, respectively. IR and Raman spectroscopy has been applied to study the effect of thermal annealing on the uncoated and coated particles. The results have shown that magnetite nano-particles are converted to maghemite at 109 Degree-Sign C and then to hematite by 500 Degree-Sign C. In contrast, the study of the effect of thermal annealing of micro-crystalline magnetite by IR spectroscopy revealed that the conversion to hematite began by 300 Degree-Sign C and that no maghemite could be identified as an intermediate phase. IR spectra and TGA measurements revealed that the Si-H and 3-aminopropyl functional groups in TES and APTMS coated magnetite nano-particles decomposed below 500 Degree-Sign C while the silica layer around the iron oxide core remained unchanged. The molecular ratio of APTMS coating to iron oxide core was determined to be 1:7 from the TGA data. Raman scattering signals have indicated that MNPs could be converted to maghemite and then to hematite using increasing power of laser irradiation in a manner similar to that observed for thermal annealing. - Highlights: Black-Right-Pointing-Pointer A modified co-precipitation method to prepare dispersive iron oxide magnetic nano-particles. Black-Right-Pointing-Pointer Coating the nano-particle with different silicas. Black-Right-Pointing-Pointer Estimating the numbers of iron oxide and 3-aminopropylsilica in the coated particles. Black-Right-Pointing-Pointer Silica coating may help to protect iron oxide nano-particles from thermal transformation.}
doi = {10.1016/J.JMMM.2011.11.065}
journal = []
issue = {8}
volume = {324}
journal type = {AC}
place = {Netherlands}
year = {2012}
month = {Apr}
}