Sonochemical Synthesis under a Magnetic Field:  Structuring Magnetite Nanoparticles and the Destabilization of a Colloidal Magnetic Aqueous Solution under a Magnetic Field

2007 ◽  
Vol 112 (1) ◽  
pp. 35-42 ◽  
Author(s):  
R. Abu-Much ◽  
A. Gedanken
Keyword(s):  
Magnetic Field ◽  
Aqueous Solution ◽  
Magnetite Nanoparticles ◽  
Sonochemical Synthesis

scholarly journals Sonochemical Synthesis of the Magnetite Nanoparticles in Aqueous Solution

2007 ◽  
Vol 115 (1348) ◽  
pp. 867-872 ◽  
Author(s):  
Feng DANG ◽  
Kai KAMADA ◽  
Naoya ENOMOTO ◽  
Junichi HOJO ◽  
Keiji ENPUKU
Keyword(s):  
Aqueous Solution ◽  
Magnetite Nanoparticles ◽  
Sonochemical Synthesis

scholarly journals Demicellization of Polyethylene Oxide in Water Solution under Static Magnetic Field Exposure Studied by FTIR Spectroscopy

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Emanuele Calabrò ◽  
Salvatore Magazù
Keyword(s):  
Magnetic Field ◽  
Aqueous Solution ◽  
Ftir Spectroscopy ◽  
Static Magnetic Field ◽  
Polyethylene Oxide ◽  
Water Solution ◽  
Infrared Region ◽  
Bending Vibrations ◽  
Field Exposure ◽  
Methylene Groups

FTIR spectroscopy was used to investigate the alterations of the vibration bands in the mid-infrared region of Polyethylene oxide in aqueous solution at 25 mg/mL concentration under exposure up to 4 h to a static magnetic field at 200 mT. FTIR spectroscopic analysis of PEO solution in the range 3500–1000 cm−1 evidenced the stretching vibrations of ether band, C–H symmetric-antisymmetric and bending vibrations of methylene groups, and the C–O–C stretching band. A significant decrease in intensity of symmetric and asymmetric stretching CH2 vibration bands occurred after 2 h and 4 h of exposure, followed by a significant decrease in intensity of scissoring bending in plane CH2 vibration around 1465 cm−1. Finally, the C–O–C stretching band around 1080 cm−1 increased in intensity after 4 h of exposure. This result can be attributed to the increase of formation of the intermolecular hydrogen bonding that occurred in PEO aqueous solution after SMF exposure, due to the reorientation of PEO chain after exposure to SMF. In this scenario, the observed decrease in intensity of CH2 vibration bands can be understood as well considering that the reorientation of PEO chain under the applied SMF induces PEO demicellization.

scholarly journals Synthesis of cobalt nanowires in aqueous solution under an external magnetic field

2016 ◽  
Vol 7 ◽  
pp. 990-994 ◽  
Author(s):  
Xiaoyu Li ◽  
Lijuan Sun ◽  
Hu Wang ◽  
Kenan Xie ◽  
Qin Long ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Aqueous Solution ◽  
External Magnetic Field ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Chemical Reduction ◽  
Average Diameter ◽  
Firm Structure ◽  
Cobalt Nanowires ◽  
First Time

In contrast to the majority of related experiments, which are carried out in organic solvents at high temperatures and pressures, cobalt nanowires were synthesized by chemical reduction in aqueous solution with the assistance of polyvinylpyrrolidone (PVP) as surfactant under moderate conditions for the first time, while an external magnetic field of 40 mT was applied. Uniform linear cobalt nanowires with relatively smooth surfaces and firm structure were obtained and possessed an average diameter of about 100 nm with a coating layer of PVP. By comparison, the external magnetic field and PVP were proven to have a crucial influence on the morphology and the size of the synthesized cobalt nanowires. The prepared cobalt nanowires are crystalline and mainly consist of cobalt as well as a small amount of platinum. Magnetic measurements showed that the resultant cobalt nanowires were ferromagnetic at room temperature. The saturation magnetization (M s) and the coercivity (H c) were 112.00 emu/g and 352.87 Oe, respectively.

scholarly journals Interlayer structure and magnetic field-induced orientation of modified nanoclays in polymer aqueous solution

Heliyon ◽  
2019 ◽  
Vol 5 (9) ◽  
pp. e02421 ◽  
Author(s):  
Min Kwan Kang ◽  
Eun Jung Cha ◽  
Hyun Hoon Song ◽  
Yang Ho Na
Keyword(s):  
Magnetic Field ◽  
Aqueous Solution ◽  
Interlayer Structure ◽  
Polymer Aqueous Solution

scholarly journals High Encapsulation Efficiency of Magnetite Nanoparticles in Hydrophobic Polymer Microcapsules using Microsuspension Conventional Radical Polymerization

2019 ◽  
Vol 35 (2) ◽  
pp. 516-522 ◽  
Author(s):  
Jittaya Sadchaiyaphum ◽  
Pongsathon Phapugrangkul ◽  
Preeyporn Chaiyasat ◽  
Amorn Chaiyasat
Keyword(s):  
Aqueous Solution ◽  
Oleic Acid ◽  
Radical Polymerization ◽  
Magnetite Nanoparticles ◽  
Driving Force ◽  
Encapsulation Efficiency ◽  
Polymer Particle ◽  
Polymer Shell ◽  
Hydrophobic Polymer ◽  
Co Precipitation

High encapsulation efficiency of magnetite nanoparticles (MNPs; Fe3O4) in microcapsules using PDVB as a hydrophobic polymer shell was successfully achieved by microsuspension conventional radical polymerization (ms CRP). MNPs were initially synthesized by co-precipitation of Fe2+/Fe3+ in a binary phase. During the nucleation of MNPs in alkaline aqueous solution existing oleic acid (OA), MNPs were coated with OA (MNPs-OA) before moving to the toluene phase with the addition of salt. At OA concentration of 0.3 wt%, most of the nucleated MNPs were hydrophobic and well dispersed in the toluene phase. Using DVB as a monomer for ms CRP, high encapsulation efficiency (92 %EE) of MNPs-OA was obtained, with low free polymer particle formation. By contrast, large amounts of free polymer particles were observed at low %EE (32%) of MNPs. The main driving force for high %EE was obtained by coating the surface of the MNPs by OA which increased hydrophobicity.

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