Profiling Pvp/Ps Homopolymer Interfaces Using Core-Loss Electron Energy-Loss Spectroscopy

1998 ◽  
Vol 4 (S2) ◽  
pp. 810-811
Author(s):  
K. Siangchaew ◽  
P. Prayoonthong ◽  
M. Libera
Keyword(s):  
Electron Scattering ◽  
Core Loss ◽  
Polymer Interfaces ◽  
Digital Analysis ◽  
Bright Field ◽  
Spatially Resolved ◽  
Optical Electron ◽  
Solid Precipitate ◽  
Electron Energy Loss ◽  
Technological Significance

Despite the physical and technological significance of polymer interfaces (1), they have not been extensively studied using techniques based on electron scattering. Spontak et al. (2) used digital analysis of bright-field images to study Os-stained polystyrene-polydiene block copolymer interfaces, but work in this area has been lacking largely because of difficulties with staining or uncertainties in the distribution of stain at the nanometer length scales relevant to interfaces. Studies of polymer interfaces are now largely done by neutron scattering (3) This research explores the application of spatially-resolved electron energyloss spectroscopy to measure compositional widths of polymer-polymer interfaces. These first studies focus on blends of poly(2-vinyl pyridine) (PVP) dispersed in poly(styrene) (PS) to establish the various electron-optical, electron-scattering, and specimen-dependent limitations (4) to resolving such an interfacial width. The uncompatibilized PS/PVP interface should be relatively sharp.Blends of PS (M.W. 190,000) and PVP ( M.W. 200,000) were made using a 5wt% solution of polymer in THF with a PS/PVP ratio of 7/3. The solution was cast into methanol. The resulting solid precipitate was removed and annealed under vacuum at 120°C for 36 hours.

Spatially Resolved Core Level Spectroscopy of Nanotubes

2005 ◽  
Vol 475-479 ◽  
pp. 4085-4088 ◽  
Author(s):  
Yue Kui Sun ◽  
Jun Yuan
Keyword(s):  
Core Loss ◽  
Direct Determination ◽  
Core Level ◽  
Magic Angle ◽  
Core Excitation ◽  
Spatially Resolved ◽  
Spectral Contribution ◽  
Sample Orientation ◽  
Electron Energy Loss

In core-level electron energy loss spectroscopy (EELS) for anisotropic systems, the applied electric field is determined by the momentum transfer vector q, therefore the collection solid angle range for the scattering electrons and sample orientation will affect the measured EELS spectra.. Using the spatially resolved C 1s core excitation in carbon nanotube as an example, we show that the EELS measurement can be understood by a simple dipole theory of anisotropic core loss spectroscopy which decomposes the spectral contribution in terms of orientationelly averaged isotropic spectrum and linear dichrotic spectrum. In addition, we point out the Magic Angle (MA) conditions that allow the direct determination of the averaged spectra acquired independent of the exact sample orientation.

Energy-Loss Measurements of Polymer Microstructure and Polymer Interfaces: Issues and Opportunities

1997 ◽  
Vol 3 (6) ◽  
pp. 530-539 ◽  
Author(s):  
K. Siangchaew ◽  
M. Libera
Keyword(s):  
Energy Loss ◽  
High Spatial Resolution ◽  
Polyphenylene Sulfide ◽  
Polymer Interfaces ◽  
Polymer Microstructure ◽  
Polymer Systems ◽  
Spatially Resolved ◽  
Transmission Electron ◽  
Homopolymer Blends ◽  
Electron Energy Loss

Abstract: The traditional methods for studying polymer microstructure in the transmission electron microscope largely hinge on the use of differential heavy-element staining to induce amplitude contrast. However, adequate staining agents are not available for all polymer systems. Furthermore, nonlinearities in the distribution of stain, particularly at interfaces, degrade the achievable resolution. Spatially resolved electron energy loss spectroscopy (EELS), on the other hand, provides a new opportunity to study polymer microstructure by providing rich spectroscopic features and high spatial resolution. Translating this opportunity into practice is underpinned by three main factors: (1) the availability of spectral fingerprints distinguishing various polymers; (2) the limits of achievable resolution; and (3) the ultimate constraints imposed by electron irradiation. This study discusses these issues and demonstrates the use of spatially resolved EELS with examples from hydrocarbon homopolymer and homopolymer blends of polyphenylene sulfide (PPS) and polyethylene terephthalate (PET), nylon 6/high-density polyethylene (HDPE) and polystyrene/polyethylene (PS/PE).

Imaging, Core-Loss, and Low-Loss Electron-Energy-Loss Spectroscopy Mapping in Aberration-Corrected STEM

2010 ◽  
Vol 16 (4) ◽  
pp. 416-424 ◽  
Author(s):  
Sorin Lazar ◽  
Yang Shao ◽  
Lina Gunawan ◽  
Riad Nechache ◽  
Alain Pignolet ◽  
...  
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Core Loss ◽  
Unit Cell ◽  
Low Loss ◽  
Bright Field ◽  
Edge Structure ◽  
Electron Energy Loss ◽  
Aberration Corrected

AbstractHigh-angle annular dark-field and annular bright-field imaging experiments were carried out on an aberration-corrected transmission electron microscope. These techniques have been demonstrated on thin films of complex oxides Ba3.25La0.75Ti3O12 and on LaB6. The results show good agreement between theory and experiments, and for the case of LaB6 they demonstrate the detection of contrast from the B atoms in the annular bright-field images. Elemental mapping with electron-energy-loss spectroscopy has been used to deduce the distribution of Cr and Fe in a thin film of the complex oxide Bi2(Fe1/2Cr3/2)O6 at the unit cell level and the changes in the near-edge structure within the inequivalent regions in the crystalline unit cell. Energy-filtered images in the low-loss region of the energy-loss spectrum show contrast and resolution consistent with the modulation of the signals from elastic scattering. High-resolution contrast, mediated by phonon scattering, is observed for interband transitions. The limitations in terms of detection and signal are discussed.

Quantitative Electron Energy Loss Mapping

1985 ◽  
Vol 43 ◽  
pp. 404-405
Author(s):  
R.D. Leapman ◽  
C.R. Swyt
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Elemental Concentration ◽  
Core Loss ◽  
Elemental Distribution ◽  
Electron Energy Loss

The intensity of a characteristic electron energy loss spectroscopy (EELS) image does not, in general, directly reflect the elemental concentration. In fact, the raw core loss image can give a misleading impression of the elemental distribution. This is because the measured core edge signal depends on the amount of plural scattering which can vary significantly from region to region in a sample. Here, we show how the method for quantifying spectra due to Egerton et al. can be extended to maps.

In Situ Analysis of Surface Contaminant Desorption during Low-Temperature Silicon Substrate Cleaning using Reflection Electron Energy Loss Spectrometry

1992 ◽  
Vol 259 ◽  
Author(s):  
Selmer S. Wong ◽  
Shouleh Nikzad ◽  
Channing C. Ahn ◽  
Aimee L. Smith ◽  
Harry A. Atwater
Keyword(s):  
Low Temperature ◽  
Energy Loss ◽  
Electron Energy ◽  
Core Loss ◽  
Temperature Dependent ◽  
Electron Energy Loss Spectrometry ◽  
Analysis Technique ◽  
Chemical Analysis Technique ◽  
Electron Energy Loss

ABSTRACTWe have employed reflection electron energy loss spectrometry (REELS), a surface chemical analysis technique, in order to analyze contaminant coverages at the submonolayer level during low-temperature in situ cleaning of hydrogen-terminated Si(100). The chemical composition of the surface was analyzed by measurements of the C K, O K and Si L2,3 core loss intensities at various stages of the cleaning. These results were quantified using SiC(100) and SiO2 as reference standards for C and O coverage. Room temperature REELS core loss intensity analysis after sample insertion reveals carbon at fractional monolayer coverage. We have established the REELS detection limit for carbon coverage to be 5±2% of a monolayer. A study of temperature-dependent hydrocarbon desorption from hydrogen-terminated Si(100) reveals the absence of carbon on the surface at temperatures greater than 200°C. This indicates the feasibility of epitaxial growth following an in situ low-temperature cleaning and also indicates the power of REELS as an in situ technique for assessment of surface cleanliness.

scholarly journals Image Formation Based on Atomic Resolution Core-loss Electron Energy Loss Spectroscopy

2006 ◽  
Vol 12 (S02) ◽  
pp. 1138-1139
Author(s):  
MP Oxley ◽  
K van Benthem ◽  
M Varela ◽  
SD Findlay ◽  
LJ Allen ◽  
...  
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Core Loss ◽  
Image Formation ◽  
Atomic Resolution ◽  
Electron Energy Loss

Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2006

Strategies for EELS Data Analysis. Introducing UMAP and HDBSCAN for Dimensionality Reduction and Clustering

2021 ◽  
pp. 1-14
Author(s):  
Javier Blanco-Portals ◽  
Francesca Peiró ◽  
Sònia Estradé
Keyword(s):  
Dimensionality Reduction ◽  
Clustering Analysis ◽  
Manganese Oxides ◽  
Spatial Clustering ◽  
State Of The Art ◽  
Core Loss ◽  
Nonnegative Matrix ◽  
Case Scenario ◽  
Electron Energy Loss ◽  
Iron And Manganese

Hierarchical density-based spatial clustering of applications with noise (HDBSCAN) and uniform manifold approximation and projection (UMAP), two new state-of-the-art algorithms for clustering analysis, and dimensionality reduction, respectively, are proposed for the segmentation of core-loss electron energy loss spectroscopy (EELS) spectrum images. The performances of UMAP and HDBSCAN are systematically compared to the other clustering analysis approaches used in EELS in the literature using a known synthetic dataset. Better results are found for these new approaches. Furthermore, UMAP and HDBSCAN are showcased in a real experimental dataset from a core–shell nanoparticle of iron and manganese oxides, as well as the triple combination nonnegative matrix factorization–UMAP–HDBSCAN. The results obtained indicate how the complementary use of different combinations may be beneficial in a real-case scenario to attain a complete picture, as different algorithms highlight different aspects of the dataset studied.

Electron Scattering in Superconducting Oxides

1987 ◽  
Vol 99 ◽  
Author(s):  
J. Ruvalds ◽  
Y. Ishu
Keyword(s):  
Transition Temperature ◽  
Energy Loss ◽  
Cross Section ◽  
Electron Scattering ◽  
Superconducting Transition Temperature ◽  
Alloy Composition ◽  
Superconducting Transition ◽  
Highly Sensitive ◽  
Superconducting Oxides ◽  
Electron Energy Loss

ABSTRACTElectron energy loss measurements on superconducting oxides are correlated with an acoustic plasm on branch whose energy and width is highly sensitive to the alloy composition. Changing oxygen content reveals structure in the electron cross section which tracks the changes in the superconducting transition temperature.

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