Self-Assembly and Graft Polymerization Route to Monodispersed Fe3O4@SiO2—Polyaniline Core–Shell Composite Nanoparticles: Physical Properties

2008 ◽  
Vol 8 (11) ◽  
pp. 5632-5639 ◽  
Author(s):  
Kakarla Raghava Reddy ◽  
Kwang-Pill Lee ◽  
Ju Young Kim ◽  
Youngil Lee
Keyword(s):  
Magnetic Nanoparticles ◽  
Self Assembly ◽  
Magnetic Particles ◽  
Graft Polymerization ◽  
Photoelectron Spectra ◽  
Core Shell ◽  
X Ray ◽  
Pl Spectra ◽  
The Core ◽  
Modified Magnetic Nanoparticles

This study describes the synthesis of monodispersed core–shell composites of silica-modified magnetic nanoparticles and conducting polyaniline by self-assembly and graft polymerization. Magnetic ferrite nanoparticles (Fe3O4) were prepared by coprecipitation of Fe+2 and Fe+3 ions in alkaline solution, and then silananized. The silanation of magnetic particles (Fe3O4@SiO2) was carried out using 3-bromopropyltrichlorosilane (BPTS) as the coupling agent. FT-IR spectra indicated the presence of Fe—O—Si chemical bonds in Fe3O4@SiO2. Core–shell type nanocomposites (Fe3O4@SiO2/PANI) were prepared by grafting polyaniline (PANI) on the surface of silanized magnetic particles through surface initiated in-situ chemical oxidative graft polymerization. The nanocomposites were characterized by high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), Fourier transform infrared (FTIR) spectra, UV-visible spectroscopy, photoluminescence (PL) spectra, electrical conductivity and magnetic characteristics. HRTEM images of the nanocomposites revealed that the silica-modified magnetic particles made up the core while PANI made up the shell. The XPS spectrum revealed the presence of silica in the composites, and the XRD results showed that the composites were more crystalline than pure PANI. PL spectra show that composites exhibit photoluminescent property. Conductivity of the composites (6.2 to 9.4 × 10−2 S/cm) was higher than that of pristine PANI (3.7 × 10−3 S/cm). The nanocomposites exhibited superparamagnetism. Formation mechanism of the core–shell structured nanocomposites and the effect of modified magnetic nanoparticles on the electro-magnetic properties of the Fe3O4@SiO2/PANI nanocomposites are also investigated. This method provides a new strategy for the generation of multi-functional nanocomposites that composed of other conducting polymers and metal nanoparticles.

Characterization of Fe3O4@CS@NMDP magnetic nanoparticles with core–shell structure prepared by chemical cross-linking method

2017 ◽  
Vol 10 (05) ◽  
pp. 1750056 ◽  
Author(s):  
Huiping Shao ◽  
Jiangcong Qi ◽  
Tao Lin ◽  
Yuling Zhou ◽  
Fucheng Yu
Keyword(s):  
Magnetic Nanoparticles ◽  
Shell Structure ◽  
High Performance ◽  
Cross Linking ◽  
Composite Particles ◽  
Core Shell ◽  
The Core ◽  
Targeting Delivery ◽  
Core Shell Structure ◽  
Chemical Cross Linking

The core–shell structure composite magnetic nanoparticles (NPs), Fe3O4@chitosan@nimodipine (Fe3O4@CS@NMDP), were successfully synthesized by a chemical cross-linking method in this paper. NMDP is widely used for cardiovascular and cerebrovascular disease prevention and treatment, while CS is of biocompatibility. The composite particles were characterized by an X-ray diffractometer (XRD), a Fourier transform infrared spectroscopy (FT-IR), a transmission electron microscopy (TEM), a vibrating sample magnetometers (VSM) and a high performance liquid chromatography (HPLC). The results show that the size of the core–shell structure composite particles is ranging from 12[Formula: see text]nm to 20[Formula: see text]nm and the coating thickness of NMDP is about 2[Formula: see text]nm. The saturation magnetization of core–shell composite NPs is 46.7[Formula: see text]emu/g, which indicates a good potential application for treating cancer by magnetic target delivery. The release percentage of the NMDP can reach 57.6% in a short time of 20[Formula: see text]min in the PBS, and to 100% in a time of 60[Formula: see text]min, which indicates the availability of Fe3O4@CS@NMDP composite NPs for targeting delivery treatment.

Dynamic calculations of the core/shell structured Ising-type endohedral fullerenes: The effect of core and core/shell interaction

2017 ◽  
Vol 31 (33) ◽  
pp. 1750307 ◽  
Author(s):  
Ersin Kantar
Keyword(s):  
Magnetic Properties ◽  
Magnetic Particles ◽  
Stochastic Dynamics ◽  
Mean Field Theory ◽  
Mean Field ◽  
Core Shell ◽  
Core Particle ◽  
Factors Affecting ◽  
The Core ◽  
First Order Phase

In this study, we examine by comparing the dynamic magnetic and hysteretic properties of Ising-type endohedral fullerene (EF) with various dopant magnetic particles confined within a spherical cage. The model of EF X@C[Formula: see text] with X = spin-1/2, spin-1 and spin-3/2 is proposed to study the effect of the nature of core particle on the magnetic properties. The results were obtained by mean-field theory as well as Glauber-type stochastic dynamics, and focused on the response of thermal and hysteretic behaviors of systems. The system exhibits second- and first-order phase transitions. In three different core cases, the system also exhibits type-II superconductivity behavior with a dynamic hysteresis curves of the core. All results display magnetic properties of the EF which strongly depend on the nature of core particle. Moreover, core particle and core/shell (C–S) interaction are proposed as the basic factors affecting the magnetic properties of EF system.

scholarly journals Modified magnetic nanoparticles by PEG-400-immobilized Ag nanoparticles (Fe3O4@PEG–Ag) as a core/shell nanocomposite and evaluation of its antimicrobial activity

2018 ◽  
Vol Volume 13 ◽  
pp. 3965-3973 ◽  
Author(s):  
Kamiar Zomorodian ◽  
Hamed Veisi ◽  
Mahmoud Mousavi ◽  
Mahmoud Ataabadi ◽  
Somayeh Yazdanpanah ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Magnetic Nanoparticles ◽  
Ag Nanoparticles ◽  
Core Shell ◽  
Peg 400 ◽  
Modified Magnetic Nanoparticles

CORE-SHELL Zn/ZnO STRUCTURES WITH IMPROVED PHOTOCATALYTIC PROPERTIES SYNTHESIZED BY AQUEOUS SOLUTION METHOD

2013 ◽  
Vol 06 (06) ◽  
pp. 1350058 ◽  
Author(s):  
YUAN MING HUANG ◽  
QING-LAN MA ◽  
BAO-GAI ZHAI
Keyword(s):  
Aqueous Solution ◽  
Photocatalytic Activity ◽  
Solution Method ◽  
Core Shell ◽  
Green Method ◽  
X Ray ◽  
The Core ◽  
Semiconductor Junction ◽  
Aqueous Solution Method ◽  
Scanning Electron

A facile and green method was utilized to synthesize core-shelled Zn / ZnO microspheres by boiling Zn microparticles in water for improving the photocatalytic activity of ZnO . The synthesized Zn / ZnO core-shells were investigated by means of scanning electron microscope, X-ray diffractometer and photoluminescence spectrometer, respectively. The morphology analysis showed that the metallic Zn core was about 6 μm in diameter while the ZnO shell was about 600 nm in thickness. Compared to ZnO nanoparticles, the core-shelled Zn / ZnO microspheres exhibited improved photocatalytic activity in degrading methyl orange in water. Our results suggest that the metal–semiconductor junction formed at the Zn / ZnO interface is responsible for the enhanced photocatalytic activity of ZnO .

Encapsulation of Magnetic Particles in Metallic Hollow Nanospheres

2001 ◽  
Vol 704 ◽  
Author(s):  
M. Toprak ◽  
D. K. Kim ◽  
M. Mikhailova ◽  
Y. Zhang ◽  
Y. K. Jeong ◽  
...  
Keyword(s):  
Magnetite Nanoparticles ◽  
Electroless Deposition ◽  
Magnetic Particles ◽  
Second Step ◽  
Core Shell ◽  
Hollow Nanospheres ◽  
Coating Solution ◽  
Porous Gold ◽  
The Core ◽  
Core Shell Structure

AbstractNovel metallic capsules containing magnetite with given size in the sub-micron range have been produced. These nanocapsules are prepared in several steps through a colloidal templating approach. The first step is the synthesis of size-selected SiO2 nanospheres. The second step is coating the SiO2nanospheres by electroless deposition with gold, in order to form a porous gold shell around the silica. Electroless deposition is controlled by the concentration of gold in the coating solution. Subsequently, the core (SiO2) was removed to obtain gold capsules. The final step is the inclusion of magnetite nanoparticles inside these nanocapsules and recoating the capsules with gold in order to have continuous encapsulation. The nanocapsule and core-shell structure have been characterized by TEM and DSC

Influence of Nanoparticle Size on Strain at the Core-Shell Interface

2015 ◽  
Vol 662 ◽  
pp. 217-220 ◽  
Author(s):  
Ondrej Milkovič ◽  
Jana Michaliková ◽  
Jozef Bednarčík ◽  
Štefan Michalik
Keyword(s):  
Solid State ◽  
High Energy ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Core ◽  
Structure Of Nanoparticles ◽  
Fe Nanoparticles ◽  
Hall Method ◽  
Core Shell Structure

This work deals with the strain at the core-shell interface of Fe nanoparticles. Series of Fe nanoparticles with various mean diameters were prepared by precipitation in solid state in binary Cu-Fe alloy. Further, nanoparticles were isolated by dissolution of Cu matrix. High-energy X-ray diffraction (XRD) was used to probe structure of nanoparticles. XRD measurements suggest presence of the core-shell structure, where core and shell of the nanoparticles are formed of α-Fe and CuFe2O4 phase, respectively. Strains in core and shell were estimated as a function of nanoparticles size by Williamson-Hall method.

Preparation of Carbon-Encapsulated Fe Core-Shell Nanostructures by Confined Arc Plasma

2011 ◽  
Vol 688 ◽  
pp. 245-249 ◽  
Author(s):  
Zhi Qiang Wei ◽  
Xiao Yun Wang ◽  
Hua Yang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Specific Surface ◽  
Surface Area ◽  
Core Shell ◽  
Arc Plasma ◽  
X Ray ◽  
The Core ◽  
Transmission Electron

Special carbon encapsulated Fe core-shell nanoparticles with a size range of 15–40 nm were successfully prepared via confined arc plasma method. The composition, morphology, microstructure, specific surface area, particle size of the product by this process were characterized via X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), X-ray energy dispersive spectrometry (XEDS) and BET N2adsorption. The experiment results shown that the carbon encapsulated Fe nanoparticles with clear core-shell structure, the core of the particles is body centered cubic (BCC) structure Fe, and the shell of the particles is disorder carbons. The particle size of the nanocapsules ranges from 15 to 40nm，with an averaged value about 30nm, the particles diameter of the core is about 16nm and the thickness of the shells is about 6-8 nm, and the specific surface area is 24 m2/g.

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