Chemical and orientational imaging of polymeric samples

1994 ◽  
Vol 52 ◽  
pp. 68-69
Author(s):  
H. Ade ◽  
B. Hsiao ◽  
G. Mitchell ◽  
E. Rightor ◽  
A. P. Smith ◽  
...  
Keyword(s):  
Ethylene Terephthalate ◽  
National Laboratory ◽  
Brookhaven National Laboratory ◽  
Carbonyl Groups ◽  
Aromatic Rings ◽  
Edge Structure ◽  
X Ray ◽  
Scanning Transmission ◽  
Polymeric Samples ◽  
X Ray Absorption

We have used the Scanning Transmission X-ray Microscope at beamline X1A (X1-STXM) at Brookhaven National Laboratory (BNL) to acquire high resolution, chemical and orientation sensitive images of polymeric samples as well as point spectra from 0.1 μm areas. This sensitivity is achieved by exploiting the X-ray Absorption Near Edge Structure (XANES) of the carbon K edge. One of the most illustrative example of the chemical sensitivity achievable is provided by images of a polycarbonate/pol(ethylene terephthalate) (70/30 PC/PET) blend. Contrast reversal at high overall contrast is observed between images acquired at 285.36 and 285.69 eV (Fig. 1). Contrast in these images is achieved by exploring subtle differences between resonances associated with the π bonds (sp hybridization) of the aromatic groups of each polymer. PET has a split peak associated with these aromatic groups, due to the proximity of its carbonyl groups to its aromatic rings, whereas PC has only a single peak.

Determination of the Cation Distribution in NiFe2(PO4)2 using Resonant X-ray and Neutron Powder Diffraction

1995 ◽  
Vol 28 (5) ◽  
pp. 494-502 ◽  
Author(s):  
J. K. Warner ◽  
A. K. Cheetham ◽  
D. E. Cox
Keyword(s):  
Powder Diffraction ◽  
National Laboratory ◽  
Time Of Flight ◽  
Brookhaven National Laboratory ◽  
Neutron Powder Diffraction ◽  
Anomalous Scattering ◽  
Edge Structure ◽  
X Ray ◽  
Scattering Correction

The distribution of divalent iron and nickel over two metal sites of differing coordination geometry in NiFe2(PO4)2, sarcopside, has been investigated by resonant X-ray and time-of-flight neutron powder diffraction. To assess the reproducibility of the X-ray technique, data have been collected from instruments X7A at Brookhaven National Laboratory and 8.3 at the Synchrotron Radiation Source, Daresbury Laboratory, England, using wavelengths λ X1 = 1.7437 (3) Å and λ X2 = 1.7434 (1) Å, respectively, close to the Fe2+ K edge determined by X-ray absorption near-edge structure. The real part of the anomalous-scattering correction for iron at each energy, f′(Fe) X1 = −7.81 (9) and f′(Fe) X2 = −10.16 (6), was determined experimentally by diffraction from Fe3(PO4)2 under identical conditions. Occupancies obtained for iron at the M(1) site were found to be M(1) X1 = 0.366 (6) and M(1) X2 = 0.376 (3), compared with M(1) N = 0.26 (15) from time-of-flight neutron powder diffraction.

Local Crystal Structure Modifications in Pulsed Laser Deposited Colossal Magnetoresistive Oxide Thin Films

2008 ◽  
Vol 1118 ◽  
Author(s):  
M. Alper Sahiner ◽  
Wiqar Shah ◽  
Marc Aranguren ◽  
Jeffrey Serfass ◽  
Joseph C. Woicik
Keyword(s):  
Thin Films ◽  
National Laboratory ◽  
Pulsed Laser ◽  
Manganese Atom ◽  
Lattice Parameter ◽  
Brookhaven National Laboratory ◽  
Least Square ◽  
Concentration Effects ◽  
X Ray ◽  
X Ray Absorption

ABSTRACTThe local structure around the manganese atom is probed by extended x-ray absorption spectroscopy (EXAFS) measurements in pulsed laser deposited thin films of La11xCaxMnO3 (x=0.1210.53). The thin films were deposited on various single crystal oxide substrates. The effect of the lattice parameter of the substrate on the local structural modifications around Mn atom is investigated. All the x-ray absorption experiments were performed at the National Synchrotron Light Source of Brookhaven National Laboratory. By detailed EXAFS theoretical modeling for the possible local structures and the least square fitting to the EXAFS data using these models, the overall substrate and the Ca concentration effects are probed. The EXAFS results indicate a rigid Mn-O bonding, but response of the Mn-O-Mn bond angle upon variations of the substrate lattice constant and Ca substitution.

Imaging, Spectroscopy and Tomography of Frozen Hydrated Specimens With the Cryo Scanning Transmission X-Ray Microscope at The NSLS

1998 ◽  
Vol 4 (S2) ◽  
pp. 354-355
Author(s):  
J. Maser ◽  
C. Jacobsen ◽  
Y. Wang ◽  
A. Osanna ◽  
B. Winn ◽  
...  
Keyword(s):  
National Laboratory ◽  
Imaging Spectroscopy ◽  
Optical Resolution ◽  
Brookhaven National Laboratory ◽  
X Rays ◽  
X Ray ◽  
Measuring Techniques ◽  
Steady Improvement ◽  
Scanning Transmission ◽  
Synchrotron Light

With the steady improvement of x-ray optics with high resolution and efficiency, and continued development or adaptation of different imaging and measuring techniques, soft x-ray microscopy has emerged as a powerful method to image and analyze fully hydrated specimens of several micrometer thickness at sub-optical resolution (for a recent overview, see ref. 1). We report on experiments performed with the cryo scanning transmission x-ray microscope (cryo-STXM), which has recently come into operation at the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory.Cryo-STXM uses x-rays with energies between the absorption edge of Carbon (E = 284 eV) and Oxygen (E = 543 eV) from the soft x-ray undulator at the NSLS. Fully hydrated specimens such as eucaryotic cells in water or ice layers of up to 10 micrometer thickness can be imaged without any additional need for contrast enhancing techniques.

X-Ray Microscopy Of Multiphase Polymeric Materials

1996 ◽  
Vol 437 ◽  
Author(s):  
H. Ade ◽  
A. P. Smith ◽  
G. R. Zhuang ◽  
B. Wood ◽  
I. Plotzker ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
National Laboratory ◽  
Polymeric Materials ◽  
High Energy ◽  
Brookhaven National Laboratory ◽  
Energy Calibration ◽  
High Energy Resolution ◽  
X Ray ◽  
Scanning Transmission ◽  
Spectral Fidelity

AbstractWe have utilized the scanning transmission x-ray microscope at Brookhaven National Laboratory to acquire high energy resolution spectra of various polymers and to investigate the bulk characteristics of multiphasic polymeric materials with chemical sensitivity at a spatial resolution of about 50 nm. We present studies ranging from phase separated liquid crystalline polyesters and polyurethanes to various polymer blends. Improvements in the NEXAFS imaging and spectral acquisition protocol in the recent past provide much improved spectral fidelity and include in situ energy calibration with CO2.

Mapping DNA and protein in biological samples using the scanning transmission x-ray microscope

1994 ◽  
Vol 52 ◽  
pp. 50-51
Author(s):  
X. Zhang ◽  
R. Balhorn ◽  
C. Jacobsen ◽  
J. Kirz ◽  
S. Williams
Keyword(s):  
Biological Samples ◽  
National Laboratory ◽  
Local Environment ◽  
High Energy ◽  
Brookhaven National Laboratory ◽  
High Energy Resolution ◽  
X Rays ◽  
X Ray ◽  
Scanning Transmission ◽  
Absorption Edges

The Scanning Transmission soft X-ray Microscope (STXM) at the XIA beamline at the National Synchrotron Light Source, Brookhaven National Laboratory, has achieved 50 nm Rayleigh resolution and has been used to image wet biological samples using the natural absorption differences between carbon and water in the water window (between carbon and oxygen K-absorption edges). The step-like jumps in the absorption of soft x-rays by materials as a function of energy have been used for elemental mapping. Examination of these absorption "edges" with high energy resolution resolves fine absorption structures. These fine structures are strongly affected by the atom's local environment, such that they carry detailed information about the atom's chemical state. We have used this chemical sensitivity to distinguish between materials which have similar elemental composition but are chemically different. Images with 50 nm resolution and spectra from a spot size less than (0.2 (μm)2 can be acquired routinely.Figure 1 shows the x-ray absorption fine structure spectra at the carbon absorption edge from DNA and bovine serum albumin (BSA, a typical protein) taken using the STXM.

Origin of luminescence from ZnO/CdS core/shell nanowire arrays

Nanoscale ◽  
2014 ◽  
Vol 6 (16) ◽  
pp. 9783-9790 ◽  
Author(s):  
Zhiqiang Wang ◽  
Jian Wang ◽  
Tsun-Kong Sham ◽  
Shaoguang Yang
Keyword(s):  
Optical Properties ◽  
Chemical Imaging ◽  
Nanowire Arrays ◽  
Nano Composites ◽  
Core Shell ◽  
Edge Structure ◽  
X Ray ◽  
Optical Luminescence ◽  
Scanning Transmission ◽  
X Ray Absorption

Chemical imaging, electronic structure and optical properties of ZnO/CdS nano-composites have been investigated using scanning transmission X-ray microscopy (STXM), X-ray absorption near-edge structure (XANES) and X-ray excited optical luminescence (XEOL) spectroscopy.

X-ray Microscopy of Polymeric Materials

1994 ◽  
Vol 375 ◽  
Author(s):  
H. Adel ◽  
B. Hsiao ◽  
G. Mitchell ◽  
E. Rightor ◽  
A. P. Smith ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
National Laboratory ◽  
Polymeric Materials ◽  
Brookhaven National Laboratory ◽  
Chemical Bonds ◽  
Chemical Sensitivity ◽  
Specific Chemical ◽  
X Ray ◽  
Oriented Samples ◽  
Scanning Transmission

AbstractWe describe how the scanning transmission x-ray microscope at Brookhaven National Laboratory can be used to investigate the bulk characteristics of polymeric materials with chemical sensitivity at a spatial resolution of about 50 nm. We present examples ranging from unoriented multiphase polymers to highly oriented Kevlar fibers. In the case of oriented samples, a dichroism technique is used to determine the orientation of specific chemical bonds. Extension of the technique to investigate surfaces of thick samples is discussed.

Large-scale hollow nanoparticle identification by X-ray absorption spectroscopy

2017 ◽  
Vol 95 (11) ◽  
pp. 1151-1155
Author(s):  
Yuanhong Tang ◽  
Zhiqiang Wang ◽  
Dongniu Wang ◽  
Jian Wang ◽  
Tsun-Kong Sham
Keyword(s):  
Absorption Spectroscopy ◽  
Chemical Bonding ◽  
Large Scale ◽  
Sol Gel ◽  
Hollow Spheres ◽  
Hollow Nanoparticles ◽  
Edge Structure ◽  
X Ray ◽  
Scanning Transmission ◽  
X Ray Absorption

Large-scale SiO2 hollow nanoparticles were synthesized by a sol-gel method. The composition, morphology, and chemical bonding information of SiO2 hollow nanoparticles were studied by X-ray absorption near edge structure (XANES) and scanning transmission X-ray microscopy (STXM). XANES at the Si L-edge and K-edge reveal the characteristics of hollow nanoparticles, which are essentially amorphous SiO2 with a slightly longer Si–O bond than SiO2 nanoparticles on average and deficiencies in oxygen. Individual SiO2 hollow spheres were also examined using STXM, which provides spectromicroscopic information, as well as the absolute thickness, of the sample.

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