Morphological study of structured latex particles by Transmission Electron Microscopy

1993 ◽  
Vol 51 ◽  
pp. 882-883
Author(s):  
Iris Segall ◽  
Olga L. Shaffer ◽  
Victoria L. Dimonie ◽  
Mohamed S. El-Aasser
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Uranyl Acetate ◽  
Structure Property ◽  
Seeded Emulsion Polymerization ◽  
Morphological Effect ◽  
Latex Particles ◽  
Structure Property Relationships ◽  
Transmission Electron ◽  
Polymerization Conditions

Transmission electron microscopy plays an important role in the study of the influence polymerization conditions have on the morphology of structured latex particles and thus in the understanding of the morphological effect of such particles on the structure-property relationships of polymeric end products.Structured latex particles are prepared by seeded emulsion polymerization, where the first stage is a polymerization of ”the core” poly(n-butyl acrylate) (PBA), followed by a second stage polymerization of ”the shell” poly(benzyl methacrylate/styrene) (P(BM/St)) at various ratios. The changes in polymerization conditions include such variables as the polymerization mode (batch vs. semicontinuous), core/shell ratio, shell thickness, and shell composition. Morphology studies of the structured latex particles are performed by transmission electron microscopy on preferentially stained samples. In a small vial, a few drops of latex sample are combined with a few drops of uranyl acetate (UAc) 2% solution. The uranyl acetate serves as a negative staining to better delineate the particles edges.

scholarly journals A Review of Grain Boundary and Heterointerface Characterization in Polycrystalline Oxides by (Scanning) Transmission Electron Microscopy

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 878
Author(s):  
Hasti Vahidi ◽  
Komal Syed ◽  
Huiming Guo ◽  
Xin Wang ◽  
Jenna Laurice Wardini ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Experimental Studies ◽  
Atomic Scale ◽  
Polycrystalline Materials ◽  
Structure Property ◽  
Ceramic Oxides ◽  
Structure Property Relationships ◽  
Transmission Electron ◽  
Scanning Transmission

Interfaces such as grain boundaries (GBs) and heterointerfaces (HIs) are known to play a crucial role in structure-property relationships of polycrystalline materials. While several methods have been used to characterize such interfaces, advanced transmission electron microscopy (TEM) and scanning TEM (STEM) techniques have proven to be uniquely powerful tools, enabling quantification of atomic structure, electronic structure, chemistry, order/disorder, and point defect distributions below the atomic scale. This review focuses on recent progress in characterization of polycrystalline oxide interfaces using S/TEM techniques including imaging, analytical spectroscopies such as energy dispersive X-ray spectroscopy (EDXS) and electron energy-loss spectroscopy (EELS) and scanning diffraction methods such as precession electron nano diffraction (PEND) and 4D-STEM. First, a brief introduction to interfaces, GBs, HIs, and relevant techniques is given. Then, experimental studies which directly correlate GB/HI S/TEM characterization with measured properties of polycrystalline oxides are presented to both strengthen our understanding of these interfaces, and to demonstrate the instrumental capabilities available in the S/TEM. Finally, existing challenges and future development opportunities are discussed. In summary, this article is prepared as a guide for scientists and engineers interested in learning about, and/or using advanced S/TEM techniques to characterize interfaces in polycrystalline materials, particularly ceramic oxides.

Diffusion Characteristics of Cu in TiN Thin Films

2001 ◽  
Vol 686 ◽  
Author(s):  
Abhishek Gupta ◽  
Hiyan Wang ◽  
Alex V. Kvit ◽  
Gerd Duscher ◽  
Jay Narayan
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Diffusion Barrier ◽  
Pulse Laser Deposition Technique ◽  
Structure Property ◽  
Contrast Imaging ◽  
Transmission Electron ◽  
Diffusion Characteristics ◽  
Tin Thin Films

AbstractWe have investigated the diffusion characteristics of Cu in nanocrystalline, polycrystalline and single crystal TiN thin films, which are being used as a diffusion barrier for sub-quarter-micron metallization. These films were synthesized on Si (100) substrate by first ablating TiN and then ablating Cu targets using Pulse Laser Deposition technique. The three different microstructures of TiN were achieved by growing the films at different substrate temperatures, where higher temperatures (650 °C) leads to epitaxy. Then a uniform thin layer of Cu was deposited on TiN/Si substrate at room temperature for all the three depositions above. These structures were characterized using X-Ray diffraction technique and high-resolution transmission electron microscopy. Each sample is then annealed at 500 °C for 30min to study the diffusion barrier characteristics as a function of microstructure of TiN. Study of diffusion profile and Cu concentration measurement were performed using Scanning Transmission Electron Microscopy-Z contrast Imaging (0.12nm resolution), Electron Energy Loss Spectroscopy and Secondary Ion Mass Spectroscopy. From the results obtained the effect of microstructure of TiN thin films on the diffusion characteristics of Cu after annealing was analyzed. Four points probe resistivity measurements were made to establish structure property correlations.

Scanning and Transmission Electron Microscopy of Human Lung in a Patient with Sarcoid-like Reaction

1974 ◽  
Vol 32 ◽  
pp. 14-15
Author(s):  
John H. L. Watson ◽  
Jessica Goodwin ◽  
E. Osborne Coates
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Hypersensitivity Reaction ◽  
Light Microscopy ◽  
Critical Point ◽  
Clinical Evidence ◽  
Human Lung ◽  
Uranyl Acetate ◽  
Lead Citrate ◽  
Transmission Electron

Biopsies of lung were taken at operation from a patient with semi-acute diffuse pulmonary infiltrates for study by TEM and SEM. Tissue by light microscopy showed non-caseating granulomas consistent with sarcoidosis. Clinical evidence suggested a hypersensitivity reaction related to inhalation of substance of undetermined nature. Samples were fixed in glutaraldehyde, cacodylate-buffered. They were critical point dried and coated with Au-Pd for SEM, and were handled appropriately for TEM in Araldite. Sections were contrasted with uranyl acetate and lead citrate.

Phosphotungstic acid staining of latexes for transmission electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 30-31
Author(s):  
O. L. Shaffer ◽  
M. S. El-Aasser ◽  
J. W. Vanderhoff
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Glass Transition ◽  
Phosphotungstic Acid ◽  
Particle Morphology ◽  
Ethyl Acrylate ◽  
Uranyl Acetate ◽  
Positive Staining ◽  
Sample Treatment ◽  
Transmission Electron

Measurement of particle size and particle morphology by transmission electron microscopy (TEM) is important in the characterization of polymer latex systems. Special sample treatment methods have been developed to permit the study of latexes that present problems, such as low-glass-transition-temperature (Tg) and electron-transparent particles. Some of these methods include hardening and staining by osmium tetroxide or bromine of latexes that contain unsaturation, negative staining by uranyl acetate, and freezing of latexes with low glass-transition temperatures.We have recently found phosphotungstic acid (PTA) to be useful in both negative and positive staining of latex particles. As a negative stain, PTA can enhance the contrast between the electron-transparent particles and the dense PTA-stained background. This has been particularly useful with latexes such as poly(butyl acrylate), poly(ethyl acrylate), poly(ethylene), and other polymers of similar electron densities. As a positive stain, PTA can also react with the surface functional groups of particles, such as hydroxyl, carboxyl, and amine groups.

TEM/STEM Characterization of Rapidly Solidified Aluminum Alloys

1985 ◽  
Vol 43 ◽  
pp. 30-31
Author(s):  
R. J. Kar ◽  
T. P. McHale ◽  
R. T. Kessler
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloys ◽  
High Strength ◽  
Advanced Materials ◽  
Structure Property ◽  
Aerospace Applications ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Rapidly Solidified

Low-density and high strength-type rapidly solidified (RST) aluminum alloys offer promise for structural aerospace applications. At Northrop, as part of a continuing program to establish structure-property relationships in advanced materials, detailed transmission electron microscopy (TEM)/scanning transmission electron microscopy (STEM) of candidate RST aluminum-lithium (Al-Li) and high strength (7XXX-type) aluminum-copper-magnesium-zinc (Al-Cu-Mg-Zn) alloys is routinely performed. This paper describes typical microstructural features that we have observed in these alloys.Figure 1 illustrates the microstructure of an inert-gas atomized RST Al-Li-Cu-Mg-Zr alloy. Frequently the grain boundaries are decorated with continuous or semi-continuous stringers of oxide that are relatively opaque to the incident electron beam. These have been identified to be Al-,Mg-, and Li- containing oxides present on powder particle surfaces prior to consolidation, and which have not been adequately broken up and dispersed by post-consolidation processing. The microstructures of these alloys are generally characterized by unrecystallized grains and equiaxed sub-grains pinned by fine (0.2μm) precipitates. These have been identified to be Al3Zr dispersoids using a combination of selected area diffraction/energy-dispersive x-ray (SAD/EDX) methods.

Uranyl acetate staining under different conditions of preparation, storage and use

1990 ◽  
Vol 48 (3) ◽  
pp. 726-727
Author(s):  
R.H.M. Cross ◽  
A.N. Hodgson ◽  
R.T.F. Bernard
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Biological Tissue ◽  
Storage Time ◽  
Uranyl Acetate ◽  
Experimental Conditions ◽  
Thin Sections ◽  
Standard Methods ◽  
Gut Epithelium ◽  
Transmission Electron

Uranyl acetate is routinely used in the staining of thin sections of biological tissue for transmission electron microscopy. Although many methods for its preparation and use have been described, there is seldom reference to the reasons for variations in concentration, solvent, storage time and staining time. Likewise, possible variations in the effects of staining under different conditions are largely ignored. In order to gain clarity on this issue an attempt has been made to test three variables (solvent, storage time and use in light or dark) under controlled experimental conditions.The tissues used for the experiment were the testis of a marine limpet, the gut epithelium of a fresh-water catfish, and the kidney of a rat; all of which were fixed and embedded by standard methods. The uranyl acetate solutions were prepared at the outset of the experiment and dispensed into small volumes and stored in the dark at 4°C until required.

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