Aromatic polyurethanes: the effect of hard segment and chain structure on their properties

2011 ◽  
Vol 31 (2-3) ◽  
Author(s):  
Abhinay Mishra ◽  
Pralay Maiti
Keyword(s):  
Hard Segment ◽  
Tensile Modulus ◽  
Chain Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Hard Segment Content ◽  
Microscopic Studies ◽  
The Difference

Abstract Structural variation and its effect on the properties of aromatic polyurethanes (PUs) with different chain structures have been reported. Polarized optical microscopic studies of aromatic PUs demonstrate the development of micro clusters with increasing hard segment content (HSC). Higher crystallinity has also been proven from differential scanning calorimeter (DSC) and X-ray diffraction (XRD) studies. A globular pattern has been observed through atomic force microscopy (AFM) and the pattern depends on the type of diisocyanate used to prepare the PU. The difference in surface morphology is evident for two different PUs. The tensile modulus increases systematically with increasing HSC while toughness decreases, due to the presence of bigger crystallites in higher HSC polymer. Both the modulus and toughness vary on the type of diisocyanate present in PUs.

Influence of Magnetic Field on Corrosion Resistance and Microstructure of Electrodeposited Ni Coatings

2011 ◽  
Vol 264-265 ◽  
pp. 1383-1388
Author(s):  
Mehdi Ebadi ◽  
Wan Jeffrey Basirun ◽  
Yatimah Alias
Keyword(s):  
Magnetic Field ◽  
Cathode Surface ◽  
X Ray Diffraction ◽  
Parallel Magnetic Field ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Presence And Absence ◽  
The Difference ◽  
Electrodeposition Of Nickel

This paper focuses on the electrodeposition of nickel from a Ni Watts solution in the presence and absence of a permanent parallel magnetic field (PPMF) to the cathode surface. It was found that the difference between the mass deposition were enhanced in the presence of PPMF and absence of a PPMF (B = 4.4 T) with increase of current density ( m= 0.413 to 4.173 mg cm2 in 6 min). The thickness of deposited layers with PPMF was smaller than without PPMF, therefore higher density of electrodeposited layers can be brought upon by the application of PPMF. The corrosion behavior of samples was tested in the presence and absence of a PPMF (9T). The Polarization resistance was reduced in the presence of the PPMF. The deposited layers were characterized by Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and Atomic force Microscopy (AFM).

Preparation and comparison of YBa2Cu4O8 films on MgO(100) and SrTiO3(100) by MOCVD

1993 ◽  
Vol 8 (9) ◽  
pp. 2143-2148 ◽  
Author(s):  
H. Sakai ◽  
Y. Shiohara ◽  
S. Tanaka
Keyword(s):  
Electron Microscopy ◽  
Lattice Mismatch ◽  
Film Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
The Difference ◽  
Xrd Patterns

The thin films (Y/Ba/Cu = 1.0/2.7/4.7) which have a strong intensity corresponding to the c-axis peaks of the 124 phase (YBa2Cu4O8) in x-ray diffraction (XRD) patterns were prepared. The film structure and surface morphology of these films were observed by scanning electron microscopy (SEM), energy dispersive x-ray (EDX), transmission electron microscopy (TEM), and atomic force microscopy (AFM). It was found that the film on MgO(100) clearly has grain boundaries with many a-axis oriented grains of the 123 phase (YBa2Cu3O7−x). However, the film on SrTiO3(100) had a smooth surface, and a-axis oriented grains of the 123 phase couldn't be observed. This difference could not be explained by only the difference in the lattice mismatch.

Morphology and Mass Changes with Magnetic Field during the Electrodeposition of Ni-Co

2011 ◽  
Vol 264-265 ◽  
pp. 1389-1394
Author(s):  
Mehdi Ebadi ◽  
Wan Jeffrey Basirun ◽  
Yatimah Alias
Keyword(s):  
Magnetic Field ◽  
Current Density ◽  
X Ray Diffraction ◽  
Parallel Magnetic Field ◽  
Cobalt Ions ◽  
Electrodeposition Process ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Difference

The influence of a static magnetic field of 4.4 T on the electrodeposition process on copper plates immersed in a solution of Nickel and Cobalt ions is presented. The electrodeposited layers characterized by Scanning Electron Microscopy (SEM) including Energy Dispersive X-Ray (EDX), X-Ray Diffraction (XRD) and Atomic Force Microscopy (AFM).It was observed that the difference between the mass of electrodeposition with the application of a Permanent Parallel Magnetic Field to the electrode surface (PPMF) and the electrodeposited layers without the PPMF, increased with the increase of current density. The presence of the PPMF gave smoother electrodeposited surface compared to without the PPMF. The increase in current density gave fewer the cracks on the electrodeposited surface.

Investigation of the Effect of Uv-Assisted Oxidation and Nitridation of Hafnium Metal Films

2003 ◽  
Vol 780 ◽  
Author(s):  
C. Essary ◽  
V. Craciun ◽  
J. M. Howard ◽  
R. K. Singh
Keyword(s):  
Uv Radiation ◽  
Photoelectron Spectroscopy ◽  
Grazing Angle ◽  
X Ray Diffraction ◽  
Metal Thin Films ◽  
X Ray ◽  
Force Microscopy ◽  
Si Substrates ◽  
Atomic Force ◽  
Silicon Interface

AbstractHf metal thin films were deposited on Si substrates using a pulsed laser deposition technique in vacuum and in ammonia ambients. The films were then oxidized at 400 °C in 300 Torr of O2. Half the samples were oxidized in the presence of ultraviolet (UV) radiation from a Hg lamp array. X-ray photoelectron spectroscopy, atomic force microscopy, and grazing angle X-ray diffraction were used to compare the crystallinity, roughness, and composition of the films. It has been found that UV radiation causes roughening of the films and also promotes crystallization at lower temperatures.Furthermore, increased silicon oxidation at the interface was noted with the UVirradiated samples and was shown to be in the form of a mixed layer using angle-resolved X-ray photoelectron spectroscopy. Incorporation of nitrogen into the film reduces the oxidation of the silicon interface.

Low Molecular Weight Microfibers with Light Sensing Properties

2017 ◽  
Vol 54 (4) ◽  
pp. 655-658
Author(s):  
Andrei Bejan ◽  
Dragos Peptanariu ◽  
Bogdan Chiricuta ◽  
Elena Bicu ◽  
Dalila Belei
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
X Ray Diffraction ◽  
Aromatic Rings ◽  
X Ray ◽  
Force Microscopy ◽  
Light Sensing ◽  
Sensing Applications ◽  
Atomic Force ◽  
Low Molecular Weight Compounds

Microfibers were obtained from organic low molecular weight compounds based on heteroaromatic and aromatic rings connected by aliphatic spacers. The obtaining of microfibers was proved by scanning electron microscopy. The deciphering of the mechanism of microfiber formation has been elucidated by X-ray diffraction, infrared spectroscopy, and atomic force microscopy measurements. By exciting with light of different wavelength, florescence microscopy revealed a specific optical response, recommending these materials for light sensing applications.

Nanocrystalline Solutions as Precursors to The Spray Deposition of Cdte Thin Films

1995 ◽  
Vol 382 ◽  
Author(s):  
Martin Pehnt ◽  
Douglas L. Schulz ◽  
Calvin J. Curtis ◽  
Helio R. Moutinho ◽  
Amy Swartzlander ◽  
...  
Keyword(s):  
Thin Films ◽  
Atomic Force Microscopy ◽  
Grain Size ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Cdte Nanoparticles ◽  
Atomic Force ◽  
Vis Spectroscopy ◽  
Cdte Thin Films

ABSTRACTIn this article we report the first nanoparticle-derived route to smooth, dense, phase-pure CdTe thin films. Capped CdTe nanoparticles were prepared by injection of a mixture of Cd(CH3)2, (n-C8H17)3 PTe and (n-C8H17)3P into (n-C8H17)3PO at elevated temperatures. The resultant nanoparticles 32-45 Å in diameter were characterized by x-ray diffraction, UV-Vis spectroscopy, transmission electron microscopy, thermogravimetric analysis and energy dispersive x-ray spectroscopy. CdTe thin film deposition was accomplished by dissolving CdTe nanoparticles in butanol and then spraying the solution onto SnO2-coated glass substrates at variable susceptor temperatures. Smooth and dense CdTe thin films were obtained using growth temperatures approximately 200 °C less than conventional spray pyrolysis approaches. CdTe films were characterized by x-ray diffraction, UV-Vis spectroscopy, atomic force microscopy, and Auger electron spectroscopy. An increase in crystallinity and average grain size as determined by x-ray diffraction was noted as growth temperature was increased from 240 to 300 °C. This temperature dependence of film grain size was further confirmed by atomic force microscopy with no remnant nanocrystalline morphological features detected. UV-Vis characterization of the CdTe thin films revealed a gradual decrease of the band gap (i.e., elimination of nanocrystalline CdTe phase) as the growth temperature was increased with bulk CdTe optical properties observed for films grown at 300 °C.

Frequency and Temperature Dependence of Dielectric Properties of Orthorhombic HoMnO3 Thin Films

2014 ◽  
Vol 1025-1026 ◽  
pp. 427-431
Author(s):  
Ping Gao ◽  
Wei Zhang ◽  
Wei Tian Wang
Keyword(s):  
Dielectric Properties ◽  
Pulsed Laser ◽  
Signal Amplitude ◽  
Debye Model ◽  
Laser Deposition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Cole Diagram

Orthorhombic HoMnO3 films were prepared epitaxially on Nb-doped SrTiO3 single crystal substrates by using pulsed laser deposition technique. The films showed perfectly a-axis crystallographic orientations. X-ray diffraction and atomic force microscopy were used to characterize the films. The complex dielectric properties were measured as functions of frequency (40 Hz~1 MHz) and temperature (80 K~300 K) with a signal amplitude of 50 mv. The respective dielectric relaxation peaks shifted to higher frequency as the measuring temperature increased, with the same development of real part of the complex permittivity. The cole-cole diagram was obtained according to the Debye model, and the effects of relaxation process were discussed.

Lateral Size of Self-Patterned Nanostructures Controlled by Multi-Step Deposition

2005 ◽  
Vol 106 ◽  
pp. 117-122 ◽  
Author(s):  
Izabela Szafraniak ◽  
Dietrich Hesse ◽  
Marin Alexe
Keyword(s):  
Electron Microscopy ◽  
Ultrathin Films ◽  
Lateral Size ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Non Volatile Memory ◽  
Ferroelectric Capacitors ◽  
Scanning Electron

Self-patterning presents an appealing alternative to lithography for the production of arrays of nanoscale ferroelectric capacitors for use in high density non-volatile memory devices. Recently a self-patterning method, based on the use of the instability of ultrathin films during hightemperature treatments, was used to fabricate nanosized ferroelectrics. This paper reports the use of the method for the preparation of PZT nanoislands on different single crystalline substrates - SrTiO3, MgO and LaAlO3. Moreover, a multi-step deposition procedure in order to control lateral the dimension of the crystals was introduced. The nanostructures obtained were studied by atomic force microscopy, scanning electron microscopy and X-ray diffraction.

Sign in / Sign up

Export Citation Format

Share Document