Fabrication and Properties of Self-Assembled Nanosized Magnetic Particles

2001 ◽  
Vol 707 ◽  
Author(s):  
G. Salazar-Alvarez ◽  
M. Mikhailova ◽  
M. Toprak ◽  
Y. Zhang ◽  
M. Muhammed
Keyword(s):  
Self Assembly ◽  
Magnetic Particles ◽  
Average Particle Size ◽  
The Self ◽  
Average Particle ◽  
Shell Nanoparticles ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Self Assembled ◽  
Core Shell Nanoparticles

ABSTRACTThe synthesis and characterisation of gold-coated cobalt nanoparticles, as well as their chemically- and magnetically-induced self-organisation have been studied. Metallic core-shell nanoparticles were prepared using two different experimental techniques: bulk reductive precipitation, with average particles size ∼15 nm, and microemulsion confining method, with average particle size of ∼6 nm. The self-assembly of prepared nanoparticles on flat substrates was achieved by derivatising the substrate and particle surfaces with bifunctional organic molecules that attaches to both particles and substrates. Examination of the self-assembled systems was carried out by a number of characterisation techniques including transmission electron microscopy (TEM), UV-visible spectrophotometry (UV-VIS), and atomic force microscopy (AFM).

Fabrication and Properties of Self-Assembled Nanosized Magnetic Particles

2001 ◽  
Vol 704 ◽  
Author(s):  
G. Salazar-Alvarez ◽  
M. Mikhailova ◽  
M. Toprak ◽  
Y. Zhang ◽  
M. Muhammed
Keyword(s):  
Self Assembly ◽  
Magnetic Particles ◽  
Average Particle Size ◽  
The Self ◽  
Average Particle ◽  
Shell Nanoparticles ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Self Assembled ◽  
Core Shell Nanoparticles

AbstractThe synthesis and characterisation of gold-coated cobalt nanoparticles, as well as their chemically- and magnetically-induced self-organisation have been studied. Metallic core-shell nanoparticles were prepared using two different experimental techniques: bulk reductive precipitation, with average particles size ∼15 nm, and microemulsion confining method, with average particle size of ∼6 nm. The self-assembly of prepared nanoparticles on flat substrates was achieved by derivatising the substrate and particle surfaces with bifunctional organic molecules that attaches to both particles and substrates.Examination of the self-assembled systems was carried out by a number of characterisation techniques including transmission electron microscopy (TEM), UV-visible spectrophotometry (UV-VIS), and atomic force microscopy (AFM).

Expanding Micelle Nanolithography to the Self-Assembly of Multicomponent Core−Shell Nanoparticles

2010 ◽  
Vol 132 (31) ◽  
pp. 10671-10673 ◽  
Author(s):  
Beri N. Mbenkum ◽  
Alejandro Díaz-Ortiz ◽  
Lin Gu ◽  
Peter A. van Aken ◽  
Gisela Schütz
Keyword(s):  
Self Assembly ◽  
The Self ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Core Shell Nanoparticles

scholarly journals Self-assembly and wetting properties of gold nanorod–CTAB molecules on HOPG

2019 ◽  
Vol 10 ◽  
pp. 696-705 ◽  
Author(s):  
Imtiaz Ahmad ◽  
Floor Derkink ◽  
Tim Boulogne ◽  
Pantelis Bampoulis ◽  
Harold J W Zandvliet ◽  
...  
Keyword(s):  
Self Assembly ◽  
Cetyltrimethylammonium Bromide ◽  
Pyrolytic Graphite ◽  
The Self ◽  
Gold Nanorod ◽  
Force Microscopy ◽  
Wetting Properties ◽  
Atomic Force ◽  
Highly Ordered Pyrolytic Graphite ◽  
Self Assembled

The formation of self-assembled superstructures of cetyltrimethylammonium bromide (CTAB) after drying on a nonwetting highly ordered pyrolytic graphite (HOPG) surface have been investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Although SEM did not reveal coverage of CTAB layers, AFM showed not only CTAB assembly, but also the dynamics of the process on the surface. The self-assembled layers of CTAB molecules on the HOPG terraces prior to nanorod deposition were shown to change the wettability of the surface, and as a result, gold nanorod deposition takes place on nonwetting HOPG terraces.

Synthesis and Characterization of Co3O4-MnxCo3-xO4 Core-Shell Nanoparticles

MRS Advances ◽  
2018 ◽  
Vol 3 (47-48) ◽  
pp. 2899-2904
Author(s):  
Ning Bian ◽  
Robert A. Mayanovic ◽  
Mourad Benamara
Keyword(s):  
Electron Microscopy ◽  
Average Particle Size ◽  
Synthesis Method ◽  
Blocking Temperature ◽  
Core Shell ◽  
Average Particle ◽  
Shell Nanoparticles ◽  
X Ray ◽  
The Core ◽  
Core Shell Nanoparticles

ABSTRACTThe mixed-valence oxide Co3O4 nanoparticles, having the normal spinel structure, possess large surface area, active-site surface adsorption properties, and fast ion diffusivities. Consequently, they are widely used in lithium-ion batteries, as well as for gas sensing and heterogeneous catalysis applications. In our research, we use a two-step method to synthesize Co3O4–based core-shell nanoparticles (CSNs). Cobalt oxide (Co3O4) nanoparticles were successfully synthesized using a wet synthesis method employing KOH and cobalt acetate. Manganese was incorporated into the Co3O4 structure to synthesize inverted Co3O4@MnxCo3-xO4 CSNs using a hydrothermal method. By adjustment of pH value, we obtained two different morphologies of CSNs, one resulting in pseudo-spherical and octahedron-shaped nanoparticles (PS type) whereas the second type predominantly have a nanoplate (NP type) morphology. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and x-ray photoelectron spectroscopy (XPS) have been performed in order to determine the morphological and structural properties of our CSNs, whereas the magnetic properties have been characterized using a superconducting quantum interference device (SQUID) magnetometer. XRD and TEM results show that the CSNs have the same spinel crystal structure throughout the core and shell with an average particle size of ∼19.8 nm. Our Co3O4 nanoparticles, as measured prior to CSN formation, are shown to be antiferromagnetic (AFM) in nature as shown by the magnetization data. Our SQUID data indicate that the core-shell nanoparticles have both AFM (due to the Co3O4 core) and ferrimagnetic properties (of the shell) with a coercivity field of 300 Oe and 150 Oe at 5 K for the PS and NP samples, respectively. The magnetization vs temperature data show a spin order-disorder transition at ∼33 K and a superparamagnetic blocking temperature of ∼90 K for both batches.

scholarly journals Effective Method for Obtaining the Hydrosols of Detonation Nanodiamond with Particle Size < 4 nm

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1285 ◽  
Author(s):  
Andrei Trofimuk ◽  
Diana Muravijova ◽  
Demid Kirilenko ◽  
Aleksandr Shvidchenko
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Synthetic Diamond ◽  
Average Particle Size ◽  
Average Particle ◽  
Detonation Nanodiamond ◽  
New Approach ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

Detonation nanodiamond is a commercially available synthetic diamond that is obtained from the carbon of explosives. It is known that the average particle size of detonation nanodiamond is 4–6 nm. However, it is possible to separate smaller particles. Here we suggest a new approach for the effective separation of detonation nanodiamond particles by centrifugation of a “hydrosol/glycerol” system. The method allows for the production of the detonation nanodiamond hydrosol with a very sharp distribution in size, where more than 85% of particles have a size ranging 1–4 nm. The result is supported by transmission electron microscopy, atomic force microscopy, and dynamic light scattering.

Ionic self-assembly of porphyrin nanostructures on the surface of charge-altered track-etched membranes

2010 ◽  
Vol 14 (05) ◽  
pp. 446-451 ◽  
Author(s):  
Nametso Mongwaketsi ◽  
Patrick G. Ndungu ◽  
Alexander Nechaev ◽  
Malik Maaza ◽  
Raymond Sparrow
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
Membrane Pore ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Self Assembled ◽  
Track Etched Membrane ◽  
Positively Charged

Track-etched polymer membranes are typically used as templates in the synthesis of various nanowires or nanotubes arrays. The unique advantages of track-etched membranes, such as uniform pore structure, excellent porosity, easily tailored pore sizes, and a well characterized surface chemistry, may find use in self-assembly strategies where colloidal nanostructures can be tethered to a suitable substrate to produce devices of interest. Meso-tetrakis(4-phenylsulfonicacid)porphyrin dihydrochloride and Sn(IV) tetrakis(4-pyridyl)porphyrin were used to synthesize ionic self-assembled porphyrin nanorods. The track-etched membranes surface charge was changed from negative to positive using polyethyleneimine. The porphyrin nanorods were either filtered through or self-assembled onto the surface of track-etched membranes. Comparisons were made with track-etched membranes modified with, and without, polyethyleneimine. Assembly of the porphyrin nanotubes only occurred on the surface of positively charged track-etched membranes, and filtration of the porphyrin nanorods produced a mesh-like structure on the surface of the membrane irrespective of the track-etched membrane pore diameter. In each case the characteristic absorbance profiles of the porphyrin nanorods was maintained. Transmission electron microscopy, scanning electron microscopy, atomic force microscopy, and UV-vis spectroscopy were used to characterize the various systems.

Well-Ordered Self-Assembly Growth of Strain-Modulated SrTiO3 Thin Films: Templates for Complex Oxide Quantum Wires

2005 ◽  
Vol 475-479 ◽  
pp. 4255-4260 ◽  
Author(s):  
Yan Rong Li ◽  
Jin Long Li ◽  
Ying Zhang ◽  
Xin Wu Deng ◽  
Fan Yang ◽  
...  
Keyword(s):  
Compressive Stress ◽  
Self Assembly ◽  
Quantum Wires ◽  
Complex Oxide ◽  
High Energy ◽  
The Self ◽  
Ex Situ ◽  
Force Microscopy ◽  
Atomic Force ◽  
Self Assembled

Well-ordered self-assembled SrTiO3 thin film, as a template for complex oxide quantum wires, was fabricated on LaAlO3 (100) single crystal substrates with laser molecular beam epitaxy. The self-assembled growth was in-situ monitored by reflective high energy electron diffraction. The morphology evolutions of the films as a function of thickness were studied by ex-situ atomic force microscopy. As the thickness of the films increased from 3.875nm to 46.5nm gradually, the compressive stress-induced SrTiO3 films exhibited a periodic well-ordered ripple structure, which formed a unique nanoassembled template for the fabrication of quantum wires. Small angle X-ray scattering technique was employed to investigate the structure. Symmetric satellite peaks were discovered, indicating the well-ordered superstructure. In contrast, the similar superstructure was not observed during the growth of the tensile stress-induced LaAlO3 films on SrTiO3 substrates. The Compressive stress was considered as the main reason of the self-assembled growth, and systematical elucidation about strain mechanism was discussed. These results might provide an efficient method for the controllable formation of well-aligned template of quantum wire for complex oxide with desirable structure via proper modulation of strains.

Fluorescent Rosette Nanotubes from the C-analogue of the Guanine–Cytosine (G∧C) Motif

2015 ◽  
Vol 1796 ◽  
pp. 1-6 ◽  
Author(s):  
Belete Legesse ◽  
Jae-Young Cho ◽  
Rachel L. Beingessner ◽  
Takeshi Yamazaki ◽  
Hicham Fenniri
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
The Self ◽  
Visible Spectroscopy ◽  
Fluorescent Properties ◽  
Force Microscopy ◽  
Rosette Nanotubes ◽  
Atomic Force ◽  
Transmission Electron ◽  
Uv Visible

ABSTRACTRosette nanotubes (RNTs) are tubular architectures generated through the hierarchical self-assembly of the guanine-cytosine (G∧C) motif 1 or 2 (Figure 1). Motif 2 differs from 1 by the substitution at the N-atom in the G-ring with a C-atom as shown in red. In this paper, we prepare a new tricyclic G∧C base 3 from a functionalized derivative of 2 and demonstrate its self-assembly into fluorescent helical RNTs in N,N-dimethylformamide (DMF). The self-assembly and fluorescent properties of RNTs 3 were established using scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM) and UV-visible spectroscopy.

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