scholarly journals Characterizing the Core-Shell Architecture of Block Copolymer Nanoparticles with Electron Microscopy: A Multi-Technique Approach

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1656
Author(s):  
Vitalii Tkachenko ◽  
Loïc Vidal ◽  
Ludovic Josien ◽  
Marc Schmutz ◽  
Julien Poly ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Block Copolymer ◽  
Self Assembly ◽  
Morphological Characterization ◽  
Spherical Particles ◽  
Core Shell ◽  
Positive Staining ◽  
Particle Volume ◽  
Core Diameter ◽  
The Core

Electron microscopy has proved to be a major tool to study the structure of self-assembled amphiphilic block copolymer particles. These specimens, like supramolecular biological structures, are problematic for electron microscopy because of their poor capacity to scatter electrons and their susceptibility to radiation damage and dehydration. Sub-50 nm core-shell spherical particles made up of poly(hydroxyethyl acrylate)–b–poly(styrene) are prepared via polymerization-induced self-assembly (PISA). For their morphological characterization, we discuss the advantages, limitations, and artefacts of TEM with or without staining, cryo-TEM, and SEM. A number of technical points are addressed such as precisely shaping of particle boundaries, resolving the particle shell, differentiating particle core and shell, and the effect of sample drying and staining. TEM without staining and cryo-TEM largely evaluate the core diameter. Negative staining TEM is more efficient than positive staining TEM to preserve native structure and to visualize the entire particle volume. However, no technique allows for a satisfactory imaging of both core and shell regions. The presence of long protruding chains is manifested by patched structure in cryo-TEM and a significant edge effect in SEM. This manuscript provides a basis for polymer chemists to develop their own specimen preparations and to tackle the interpretation of challenging systems.

Magnetic Properties of Fe3O4/CoFe2O4 Composite Nanoparticles with Core/Shell Architecture

2020 ◽  
Vol 65 (10) ◽  
pp. 904
Author(s):  
V. O. Zamorskyi ◽  
Ya. M. Lytvynenko ◽  
A. M. Pogorily ◽  
A. I. Tovstolytkin ◽  
S. O. Solopan ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Spinel Ferrite ◽  
Composite Nanoparticles ◽  
Core Shell ◽  
Cofe2o4 Nanoparticles ◽  
Core Diameter ◽  
The Core ◽  
Shell Particles ◽  
Interface Parameters ◽  
Shell Composite

Magnetic properties of the sets of Fe3O4(core)/CoFe2O4(shell) composite nanoparticles with a core diameter of about 6.3 nm and various shell thicknesses (0, 1.0, and 2.5 nm), as well as the mixtures of Fe3O4 and CoFe2O4 nanoparticles taken in the ratios corresponding to the core/shell material contents in the former case, have been studied. The results of magnetic research showed that the coating of magnetic nanoparticles with a shell gives rise to the appearance of two simultaneous effects: the modification of the core/shell interface parameters and the parameter change in both the nanoparticle’s core and shell themselves. As a result, the core/shell particles acquire new characteristics that are inherent neither to Fe3O4 nor to CoFe2O4. The obtained results open the way to the optimization and adaptation of the parameters of the core/shell spinel-ferrite-based nanoparticles for their application in various technological and biomedical domains.

Electron Microscopy Study of Submicron Size Antiferromagnetic KMnF3 Nanoparticles and Their Self-assembly

2003 ◽  
Vol 775 ◽  
Author(s):  
Jeffrey Anderson ◽  
Rubi Garcia ◽  
Weilie L. Zhou
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
Room Temperature ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Submicron Particles ◽  
Spherical Particles ◽  
Large Area ◽  
Homogeneous Crystal ◽  
Field Emission Electron Microscopy

AbstractSubmicron KMnF3 cubic and spherical nanoparticles were synthesized using the reverse micelle method. The nanostructures of the nanocrystals were studied by field emission electron microscopy and transmission electron microscopy. KMnF3 nanocrystals synthesized at room temperature started with cubic submicron particles (∼100 nm) and consisted of KMnF3 nanocrystallites (10-15 nm). As the reaction continued, the nanocrystals fused together and transformed into perfect cubic nanocrystals. Spherical beads composed of KMnF3 nanocrystallites were observed at low temperature synthesis. As the reaction continued, the spherical particles grew larger, however, no characteristic cubic shape of KMnF3 nanoparticles were observed. Even as they grew larger, there was no evidence of homogeneous crystal morphology as seen in the room temperature samples. Cubic shape KMnF3 nanocrystals were self-assembled into large area self-assembling patterns.

Formation of bismuth iron oxide based core–shell structures and their dielectric, ferroelectric and magnetic properties

2019 ◽  
Vol 7 (5) ◽  
pp. 1280-1291 ◽  
Author(s):  
Alaka Panda ◽  
R. Govindaraj ◽  
R. Mythili ◽  
G. Amarendra
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Magnetic Properties ◽  
Iron Oxide ◽  
Shell Structures ◽  
Core Shell ◽  
Bismuth Iron Oxide ◽  
The Core ◽  
Shell Nanostructures ◽  
Transmission Electron

Bismuth and iron oxides subjected to ball milling followed by controlled annealing treatments showed the formation of core–shell nanostructures with Bi2Fe4O9 as the core and a shell of BiFeO3 and Bi25FeO40 phases as deduced based on the analysis of transmission electron microscopy results.

Preparation of PS@SiO2, PS@TiO2，PS@TiO2/SiO2 Core-Shell Composites by a Spray Drying Process and Their Hollow Spheres after Removing PS Cores by Calcinations

2011 ◽  
Vol 194-196 ◽  
pp. 389-392
Author(s):  
Ling Li ◽  
Hong Liang Li ◽  
Ying Chun Zhu ◽  
Ai Ping Fu ◽  
Yong Wan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Spray Drying ◽  
Hollow Spheres ◽  
Nitrogen Adsorption ◽  
Core Shell ◽  
Drying Process ◽  
The Core ◽  
Adsorption Desorption ◽  
Drying Chamber ◽  
Scanning Electron

Polystyrene (PS) spheres encapsulated core-shell composites of SiO2or TiO2nanoparticles were prepared by the spray drying technique and hollow spheres of SiO2or TiO2nanoparticles were then derived by removing the PS cores with calcinations. The PS spheres were dispersed into the SiO2or TiO2colloids, forming a suspension and then the suspensions were sprayed to form micrometer-sized droplets, as the droplets rush through the drying chamber, the PS spheres were encapsulated into the core of SiO2or TiO2particles due to the high temperatures and the instant evaporation, obtaining PS@SiO2, PS@TiO2or PS@SiO2/TiO2core-shell composites. After removing the PS core by calcination at 550°C, SiO2or TiO2hollow spheres were then derived. The influence of drying temperature, the concentration of the SiO2or TiO2particles and the ratio of PS sphere to the particles on the structures and specific surface area of the hollow spheres were studied with scanning electron microscopy (SEM) and nitrogen adsorption-desorption measurements.

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.

Nano-structuring polymer/fullerene composites through the interplay of conjugated polymer crystallization, block copolymer self-assembly and complementary hydrogen bonding interactions

2015 ◽  
Vol 6 (5) ◽  
pp. 721-731 ◽  
Author(s):  
Fei Li ◽  
Kevin G. Yager ◽  
Noel M. Dawson ◽  
Ying-Bing Jiang ◽  
Kevin J. Malloy ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Block Copolymer ◽  
Supramolecular Chemistry ◽  
Self Assembly ◽  
Conjugated Polymer ◽  
Composite Nanofibers ◽  
Core Shell ◽  
Hydrogen Bonding Interactions ◽  
Non Covalent Interactions ◽  
Covalent Interactions

Core–shell P3HT/fullerene composite nanofibers were obtained using supramolecular chemistry involving cooperative orthogonal non-covalent interactions.

scholarly journals Observation and Analysis of an Electrically Active Layer at the Core-Shell Interface of a GaN Nanowire by Advanced Electron Microscopy

2017 ◽  
Vol 23 (S1) ◽  
pp. 1406-1407
Author(s):  
S. Yazdi ◽  
T. Kasama ◽  
R. Ciechonski ◽  
J. B. Wagner ◽  
R. E. Dunin-Borkowski ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Active Layer ◽  
Core Shell ◽  
The Core ◽  
Gan Nanowire
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