Structure of Self-assembled Magnetic FePtCu Nanoparticles Arrays

2003 ◽  
Vol 775 ◽  
Author(s):  
Xiangcheng Sun ◽  
J.W. Harrell ◽  
D. E. Nikles ◽  
K. Sun ◽  
L. M. Wang ◽  
...  
Keyword(s):  
Average Diameter ◽  
Iron Pentacarbonyl ◽  
Particle Packing ◽  
Three Dimensions ◽  
Face Centered Cubic ◽  
Oleyl Amine ◽  
Organic Surfactant ◽  
Self Assembled ◽  
Face Centered ◽  
Organic Capping

AbstractIn this study, a series of FexPtyCu100-x-y nanoparticles were chemically synthesized by solution-phase reduction of platinum and copper reagents and thermal decomposition of iron pentacarbonyl in the presence of stabilizers oleic acid and oleyl amine. As-prepared particles had a chemically disordered face-centered cubic (fcc) lattice with an average diameter of 3.5 nm. The particle size, and the corresponding size distribution were controlled by varying the organic surfactant (oleic acids, etc.), its concentration, and the reaction temperature. These particles were well dispersed in hydrocarbon solvents and self-assembled into two or three dimensions particles arrays with a variety of closepacking arrangements. Domain of monolayers, bilayers and multilayers of particles arrays were frequently detected in TEM specimens. Both cubic close-packed (ccp) and honeycomb arrays were also uniquely observed. It was also demonstrated that the controlled organic surfactant layer (organic capping) play a crucial role in determining assembly dimensions and symmetry as well as particle packing arrays.

Synthesis, Self-assembly and Magnetic Properties of FePtCu Nanoparticle Arrays

2002 ◽  
Vol 739 ◽  
Author(s):  
Xiangcheng Sun ◽  
S. S. Kang ◽  
J. W. Harrell ◽  
David E. Nikles ◽  
Z. R. Dai ◽  
...  
Keyword(s):  
Self Assembly ◽  
Magnetic Hysteresis ◽  
Average Diameter ◽  
Iron Pentacarbonyl ◽  
Close Packing ◽  
Three Dimensions ◽  
Second Phase ◽  
Hard Component ◽  
Extra Peak ◽  
Self Assembled

ABSTRACTFePtCu nanoparticles with varying composition were synthesized by chemical solution-phase reduction of platinum and copper reagents and thermal decomposition of iron pentacarbonyl in the presence of oleic acid and oleyl amine stabilizers. As prepared the particles had fcc structure with an average diameter of 3.5 nm and were superparamagnetic. The particles were well dispersed in hydrocarbon solvents and could be self-assembled into two or three dimensions particles arrays with a variety of close-packing arrangements. Heat-treatment of the self-assembled films at temperatures above 550°C transformed the particles from the fcc to the L10 phase, giving in-plane coercivities as high as 9000 Oe. X-ray diffraction revealed that the Cu remained in the annealed FePtCu films and the presence of an extra peak, indicated a second phase was present. Consistent with one or more phases, the magnetic hysteresis curves could be decomposed into a hard component (Hc > 5,000 Oe) and a soft component (Hc < 2,000 Oe). Unlike our earlier results for Ag in FePt, adding Cu to FePt did not lower the temperature required for phase transformation from the fcc to the fct L10 phase.

Synthesis and Self-Assembly of Films Containing FeCoPt Nanoparticles

2001 ◽  
Vol 674 ◽  
Author(s):  
Min Chen ◽  
David E. Nikles
Keyword(s):  
Self Assembly ◽  
Annealing Temperature ◽  
Chemical Reduction ◽  
Average Diameter ◽  
Iron Pentacarbonyl ◽  
Face Centered Cubic ◽  
Oxidized Iron ◽  
Carbon Coated ◽  
Face Centered ◽  
Cobalt Acetylacetonate

ABSTRACTFe49Co7Pt44 and Fe40Co17Pt43nanoparticles were synthesized by simultaneous chemical reduction of platinum acetylacetonate and cobalt acetylacetonate and thermal decomposition of iron pentacarbonyl. As-prepared the particles had a disordered face-centered cubic lattice with an average diameter of 3.2 nm and were superparamagnetic. These particles were well dispersed in a 50/50 mixture of hexane and octane. The particles self-assembled into ordered superlattices when deposited onto carbon coated Cu TEM grids or onto single crystal Si (100) substrates. After vacuum annealing (from 500°C to 700 °C), the particles transformed to the tetragonal phase. The coercivity of the film strongly depended on the composition and annealing temperature. For the Fe49Co7Pt44film, coercivity of 8700 Oe and a squareness of 0.75 after annealing at 700 °C for 30 minutes. XPS shows existance of oxidized iron and cobalt on the surface of film.

scholarly journals Superhydrophilic Coating of Pine Wood by Plasma Functionalization of Self-Assembled Polystyrene Spheres

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 114
Author(s):  
Sebastian Dahle ◽  
John Meuthen ◽  
René Gustus ◽  
Alexandra Prowald ◽  
Wolfgang Viöl ◽  
...  
Keyword(s):  
Dip Coating ◽  
Face Centered Cubic ◽  
Wood Substrate ◽  
Polystyrene Spheres ◽  
Pine Wood ◽  
Self Assembling ◽  
Monodisperse Polystyrene ◽  
Self Assembled ◽  
Face Centered ◽  
Plasma Functionalization

Self-assembling films typically used for colloidal lithography have been applied to pine wood substrates to change the surface wettability. Therefore, monodisperse polystyrene (PS) spheres have been deposited onto a rough pine wood substrate via dip coating. The resulting PS sphere film resembled a polycrystalline face centered cubic (FCC)-like structure with typical domain sizes of 5–15 single spheres. This self-assembled coating was further functionalized via an O2 plasma. This plasma treatment strongly influenced the particle sizes in the outermost layer, and hydroxyl as well as carbonyl groups were introduced to the PS spheres’ surfaces, thus generating a superhydrophilic behavior.

scholarly journals Identification of Local Structure in 2-D and 3-D Atomic Systems through Crystallographic Analysis

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1008
Author(s):  
Pablo Miguel Ramos ◽  
Miguel Herranz ◽  
Katerina Foteinopoulou ◽  
Nikos Ch. Karayiannis ◽  
Manuel Laso
Keyword(s):  
Local Structure ◽  
Point Group ◽  
Local Symmetry ◽  
Crystallographic Analysis ◽  
Three Dimensions ◽  
Group Symmetry ◽  
Spherical Particles ◽  
Specific Reference ◽  
Face Centered Cubic ◽  
Face Centered

In the present work, we revise and extend the Characteristic Crystallographic Element (CCE) norm, an algorithm used to simultaneously detect radial and orientational similarity of computer-generated structures with respect to specific reference crystals and local symmetries. Based on the identification of point group symmetry elements, the CCE descriptor is able to gauge local structure with high precision and finely distinguish between competing morphologies. As test cases we use computer-generated monomeric and polymer systems of spherical particles interacting with the hard-sphere and square-well attractive potentials. We demonstrate that the CCE norm is able to detect and differentiate, between others, among: hexagonal close packed (HCP), face centered cubic (FCC), hexagonal (HEX) and body centered cubic (BCC) crystals as well as non-crystallographic fivefold (FIV) local symmetry in bulk 3-D systems; triangular (TRI), square (SQU) and honeycomb (HON) crystals, as well as pentagonal (PEN) local symmetry in thin films of one-layer thickness (2-D systems). The descriptor is general and can be applied to identify the symmetry elements of any point group for arbitrary atomic or particulate system in two or three dimensions, in the bulk or under confinement.

scholarly journals Self-Assembled Fullerene Crystals as Excellent Aromatic Vapor Sensors

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 267 ◽  
Author(s):  
Natsumi Furuuchi ◽  
Rekha Shrestha ◽  
Yuji Yamashita ◽  
Tetsuji Hirao ◽  
Katsuhiko Ariga ◽  
...  
Keyword(s):  
Average Length ◽  
Fullerene C60 ◽  
Nanoporous Structure ◽  
Face Centered Cubic ◽  
Bitter Melon ◽  
Vapor Sensing ◽  
Porous Architecture ◽  
Vapor Sensors ◽  
Self Assembled ◽  
Face Centered

Here we report the aromatic vapor sensing performance of bitter melon shaped nanoporous fullerene C60 crystals that are self-assembled at a liquid-liquid interface between isopropyl alcohol and C60 solution in dodecylbenzene at 25 °C. Average length and center diameter of the crystals were ca. 10 μm and ~2 μm, respectively. Powder X-ray diffraction pattern (pXRD) confirmed a face-centered cubic (fcc) structure with cell dimension ca. a = 1.4272 nm, and V = 2.907 nm3, which is similar to that of the pristine fullerene C60. Transmission electron microscopy (TEM) confirmed the presence of a nanoporous structure. Quartz crystal microbalance (QCM) results showed that the bitter melon shaped nanoporous C60 performs as an excellent sensing system, particularly for aromatic vapors, due to their easy diffusion through the porous architecture and strong π–π interactions with the sp2-carbon.

scholarly journals Close-packed block copolymer micelles induced by temperature quenching

2018 ◽  
Vol 115 (28) ◽  
pp. 7218-7223 ◽  
Author(s):  
Liwen Chen ◽  
Han Seung Lee ◽  
Sangwoo Lee
Keyword(s):  
Block Copolymer ◽  
Spherical Particles ◽  
Face Centered Cubic ◽  
Time Resolved ◽  
Hexagonal Close Packed ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles ◽  
Crystal Grains ◽  
Self Assembled ◽  
Face Centered

Close-packed structures of uniformly sized spheres are ubiquitous across diverse material systems including elements, micelles, and colloidal assemblies. However, the controlled access to a specific symmetry of self-assembled close-packed spherical particles has not been well established. We investigated the ordering of spherical block copolymer micelles in aqueous solutions that was induced by rapid temperature changes referred to as quenching. As a function of quench depth, the quenched self-assembled block copolymer micelles formed three different close-packed structures: face-centered cubic (fcc), random stacking of hexagonal-close-packed layers (rhcp), and hexagonal-close-packed (hcp). The induced hcp and rhcp structures were stable for at least a few weeks when maintained at their quench temperatures, but heating or cooling these hcp and rhcp structures transformed both structures to fcc crystallites with coarsening of the crystal grains, which suggests that these noncubic close-packed structures are intermediate states. Time-resolved scattering experiments prove that the micellar rhcp structures do not originate from the rapid growth of competing close-packed structures. We speculate that the long-lived metastable hcp and rhcp structures originate from the small size of crystal grains, which introduces a nonnegligible Laplace pressure to the crystal domains. The reported transitions from the less stable hcp to the more stable rhcp and fcc are experimental observations of Ostwald’s rule manifesting the transition order of the key close-packed structures in the crystallization of close-packed uniform spheres.

scholarly journals Effect of feed supplementation with biosynthesized silver nanoparticles using leaf extract of Morus indica L. V1 on Bombyx mori L. (Lepidoptera: Bombycidae)

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Sudip Some ◽  
Onur Bulut ◽  
Kinkar Biswas ◽  
Anoop Kumar ◽  
Anupam Roy ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Bombyx Mori ◽  
Leaf Extract ◽  
Silver Ions ◽  
Average Diameter ◽  
Face Centered Cubic ◽  
Tem Analysis ◽  
Beneficial Effects ◽  
Selected Area Electron Diffraction ◽  
Face Centered

Abstract Herein, we report the synthesis of silver nanoparticles (AgNPs) by a green route using the aqueous leaf extract of Morus indica L. V1. The synthesized AgNPs exhibited maximum UV-Vis absorbance at 460 nm due to surface plasmon resonance. The average diameter (~54 nm) of AgNPs was measured from HR-TEM analysis. EDX spectra also supported the formation of AgNPs, and negative zeta potential value (−14 mV) suggested its stability. Moreover, a shift in the carbonyl stretching (from 1639 cm−1 to 1630 cm−1) was noted in the FT-IR spectra of leaf extract after AgNPs synthesis which confirm the role of natural products present in leaves for the conversion of silver ions to AgNPs. The four bright circular rings (111), (200), (220) and (311) observed in the selected area electron diffraction pattern are the characteristic reflections of face centered cubic crystalline silver. LC-MS/MS study revealed the presence of phytochemicals in the leaf extract which is responsible for the reduction of silver ions. MTT assay was performed to investigate the cytotoxicity of AgNPs against two human cell lines, namely HepG2 and WRL-68. The antibacterial study revealed that MIC value of the synthesized AgNPs was 80 µg/ml against Escherichia coli K12 and Staphylococcus aureus (MTCC 96). Finally, the synthesized AgNPs at 10 µg/ml dosages showed beneficial effects on the survivability, body weights of the Bombyx mori L. larvae, pupae, cocoons and shells weights via enhancing the feed efficacy.

scholarly journals Exploration of the Antimicrobial and Catalytic Properties of Gold Nanoparticles Greenly Synthesized by Cryptolepis buchanani Roem. and Schult Extract

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Kamonpan Wongyai ◽  
Phitchayapak Wintachai ◽  
Rasimate Maungchang ◽  
Parawee Rattanakit
Keyword(s):  
Staphylococcus Aureus ◽  
Gold Nanoparticles ◽  
Analytical Techniques ◽  
Average Diameter ◽  
Face Centered Cubic ◽  
Tem Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Face Centered

A green, simple, and rapid synthesis of gold nanoparticles using plant extract, Cryptolepis buchanani Roem. and Schult, and their applications are first described in this paper. The formation of gold nanoparticles was visually observed by the appearance of a ruby red color, which was further indicated by an absorption peak at 530 nm in UV-Vis spectroscopy. Optimization of reaction parameters for the gold nanoparticles was also investigated. Various analytical techniques were employed as part of the process of characterizing the resulting gold nanoparticles. Fourier transform infrared (FTIR) analysis revealed that the phenol compounds present in the extract were responsible for gold(III) reduction and stabilization of gold nanoparticles. Transmission electron microscopy (TEM) analysis showed that the gold nanoparticles were spherical in shape with an average diameter of 11 nm. Powder X-ray diffraction (XRD) pattern indicated that the green synthesis approach produced highly crystalline, face-centered cubic gold nanoparticles. Energy-dispersive X-ray spectroscopy (EDS) measurements confirmed the presence of elemental gold in the prepared nanoparticles. The negative zeta potential value of gold nanoparticles was found to be -30.28 mV. The green synthesized gold nanoparticles expressed effective antibacterial activity against Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, and Acinetobacter baumannii and exhibited an excellent catalytic property in terms of its reduction ability of methylene blue.

Effects of Substrates on the Self-Assembling of FePt Nanocrystals

2001 ◽  
Vol 674 ◽  
Author(s):  
Min Chen ◽  
David E. Nikles
Keyword(s):  
Chemical Reduction ◽  
Average Diameter ◽  
Iron Pentacarbonyl ◽  
Fept Nanoparticles ◽  
Hexagonal Close Packed ◽  
Self Assembling ◽  
Hydrocarbon Solvents ◽  
Carbon Coated ◽  
Self Assembled ◽  
Hexagonal Arrays

ABSTRACTFe48Pt52 nanoparticles were synthesized by the simultaneous chemical reduction of platinum acetylacetonate and thermal decomposition of iron pentacarbonyl. As-prepared the particles were spherical with an average diameter of 3 nm and a polydispersity of less than 5%. The particles were superparamagnetic and had a fcc structure. Highly ordered self-assembled supercrystals of particles were formed in TEM grids by deposition from dispersions in hydrocarbon solvents. Nanoparticles deposited on amorphous carbon-coated and SiO2-coated Cu grids tend to assemble into small domains of hexagonal arrays. Larger domains of hexagonal arrays formed on Si3N4 membrane TEM grids. For thin multilayers, the FePt nanoparticles tends to assemble into hexagonal close-packed lattices (ABABAB stacking). For the thicker multilayers, ABCABC stacking was observed. Small angle X-ray reflectivity of the particles on a Si (100) substrate show highly ordered multiplanar structure with d-spacing of 6.2 nm. The coercivity of self-assembled FePt films strongly depended on the annealing temperature. After annealing at 700°C for 30 minutes, the particles transformed from FCC to “FCT” phase and the coercivity of film increased up to 11570 Oe. However, the particle size increased to 16 nm due to sintering.

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