scholarly journals Morphological Transformation and Photophysical Properties of Polyfluorene-Based Luminescent Rod-Coil Block Copolymers

2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Yang-Yen Yu ◽  
Chun-Yen Huang
Keyword(s):  
Thermal Stability ◽  
Block Copolymers ◽  
Fluorescence Quenching ◽  
Fluorescence Spectra ◽  
Annealing Temperature ◽  
Photophysical Properties ◽  
Morphological Transformation ◽  
Solvent Selectivity ◽  
Thermal Stability Of

The morphologies, synthesis, and photophysical characterizations of poly[2,7-(9,9-dihexylfluorene)]-block-poly(2-(diethylamino)ethylmethacrylate) using amphiphilic rod-coil (PF-b-PDEAEMA) were demonstrated. The aggregation morphologies of PF13-b-PDEAEMA100 were manipulated by tuning the selectivity of mixed THF/methanol solvents with methanol contents ranging from 0 to 90 vol%. The morphological transformation of PF13-b-PDEAEMA100 caused significant changes in its photophysical properties, including absorption, fluorescence spectra, and fluorescence quenching. Moreover, the thermal stability of PF13-b-PDEAEMA100 was investigated by varying the annealing temperature. The results of the present study suggest that the solvent selectivity influences the photophysical properties and aggregation morphologies of rod-coil block copolymers in solid and solution states.

Thermal Stability of Ultrafine-Grained Pure Titanium Processed by High-Pressure Torsion

2021 ◽  
Vol 1016 ◽  
pp. 338-344
Author(s):  
Wan Ji Chen ◽  
Jie Xu ◽  
De Tong Liu ◽  
De Bin Shan ◽  
Bin Guo ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Grain Size ◽  
High Pressure ◽  
Annealing Temperature ◽  
High Pressure Torsion ◽  
Stored Energy ◽  
Ultrafine Grained ◽  
Average Grain Size ◽  
Thermal Stability Of

High-pressure torsion (HPT) was conducted under 6.0 GPa on commercial purity titanium up to 10 turns. An ultrafine-grained (UFG) pure Ti with an average grain size of ~96 nm was obtained. The thermal properties of these samples were studied by using differential scanning calorimeter (DSC) which allowed the quantitative determination of the evolution of stored energy, the recrystallization temperatures, the activation energy involved in the recrystallization of the material and the evolution of the recrystallized fraction with temperature. The results show that the stored energy increases, beyond which the stored energy seems to level off to a saturated value with increase of HPT up to 5 turns. An average activation energy of about 101 kJ/mol for the recrystallization of 5 turns samples was determined. Also, the thermal stability of the grains of the 5 turns samples with subsequent heat treatments were investigated by microstructural analysis and Vickers microhardness measurements. It is shown that the average grain size remains below 246 nm when the annealing temperature is below 500 °C, and the size of the grains increases significantly for samples at the annealing temperature of 600 °C.

Effect of annealing temperature on the thermal stability of FeCrNiMnMoxSi0.5B0.5 coatings

2019 ◽  
Vol 35 (11) ◽  
pp. 962-969 ◽  
Author(s):  
Ying Zhu ◽  
Xiong Ya Guo ◽  
Cheng Wen Liu ◽  
Fang Zhou ◽  
Bin Qi Liu
Keyword(s):  
Thermal Stability ◽  
Annealing Temperature ◽  
Thermal Stability Of

Dependence of Vickers Hardness on Annealing Temperature at Co/Cu Multilayered Films

2007 ◽  
Vol 561-565 ◽  
pp. 2399-2402
Author(s):  
Yoshihisa Kaneko ◽  
H. Sakakibara ◽  
Satoshi Hashimoto
Keyword(s):  
Thermal Stability ◽  
Vickers Hardness ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Copper Substrate ◽  
The Other ◽  
Multilayered Structures ◽  
Multilayered Films ◽  
Hardness Tests ◽  
Thermal Stability Of

Co/Cu and Ni/Cu multilayers fabricated by electroplating technique were annealed at various temperatures in order to investigate thermal stability of multilayered structures. Vickers hardness tests on the annealed Co/Cu and Ni/Cu multilayers were conducted at room temperature. It was recognized that after the annealing at 1023K the Co/Cu multilayer still maintained the hardness of as-deposited state. On the other hand, the hardness of Ni/Cu multilayer was almost identical to copper substrate after the annealing at 903K.

Implant isolation of ZnO epitaxial layers

2002 ◽  
Vol 744 ◽  
Author(s):  
S. O. Kucheyev ◽  
C. Jagadish ◽  
J. S. Williams ◽  
P. N. K. Deenapanray ◽  
Mitsuaki Yano ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Single Crystal ◽  
Sheet Resistance ◽  
Annealing Temperature ◽  
Ion Beam ◽  
Irradiation Temperature ◽  
Minor Effect ◽  
Electrical Isolation ◽  
Atomic Displacements ◽  
Thermal Stability Of

ABSTRACTThe formation of highly resistive films of single-crystal ZnO as a result of irradiation with MeV Li, O, and Si ions is demonstrated. Results show that the ion doses necessary for electrical isolation close-to-inversely depend on the number of ion-beam-generated atomic displacements. Results show that an increase in the dose of 2 MeV O ions (up to ∼ 2 orders of magnitude above the threshold isolation dose) and irradiation temperature (up to 350 °C) has a relatively minor effect on the thermal stability of electrical isolation, which is limited to temperatures of ∼ 300 — 400 °C. For the case of multiple-energy implantation with keV Cr, Fe, or Ni ions, the evolution of sheet resistance with annealing temperature is consistent with defect-induced isolation, with a relatively minor effect of Cr, Fe, or Ni impurities on the thermal stability of isolation. Based on these results, the mechanism for electrical isolation in ZnO by ion bombardment is discussed.

Synthesis, Morphology and Photophysical Properties of Rod-Coil Copolymers

2009 ◽  
Vol 79-82 ◽  
pp. 2095-2098
Author(s):  
Yang Yen Yu ◽  
Wen Chen Chien ◽  
Chung Yi Hsu
Keyword(s):  
Photophysical Properties ◽  
Mixed Solvents ◽  
Blue Shift ◽  
Morphological Transformation ◽  
Good Thermal Stability ◽  
Lamellar Morphology ◽  
Long Rod ◽  
Spherical Micelles ◽  
Large Compound ◽  
Thermal Stability Of

The synthesis, morphology, and photophysical properties of poly[2,7-(9,9- dihexylfluorene)]-block-poly(2-vinyl pyridine) (PF-b-P2VP) with different coil lengths in mixed solvents of THF/methanol are reported. A flakes-like lamellar morphology is observed at a short coil length of PF-b-P2VP. As the coil length increases, a spherical and large compound micelle is formed. Upon further increase of the coil length, the morphological transformation from spherical micelles to long rod-like structures is observed. TGA results indicate a good thermal stability of the prepared copolymers. The spectra of optical absorption for the PF-b-P2VP in solution have a blue shift when the fraction of methanol in the mixed solvent increases. The present study shows that the significance of the rod/coil ratio and selective solvent content on the aggregate morphologies and photophysical properties of the rod-coil block copolymers.

Thermal Stability of Platinum Silicide in Deep Sub-Micron Lines

1995 ◽  
Vol 391 ◽  
Author(s):  
Dan-Xia Xu ◽  
Suhit R. Das ◽  
Lynden Erickson ◽  
Abdalla Naem
Keyword(s):  
Thermal Stability ◽  
Sheet Resistance ◽  
Annealing Temperature ◽  
Electrical Conductance ◽  
Sharp Decrease ◽  
Platinum Silicide ◽  
Deflection System ◽  
Stability Of Resistance ◽  
Pt Films ◽  
Thermal Stability Of

AbstractThe properties of platinum silicide have been evaluated in the form of blanket films and confined lines with linewidth down to 0.15 μm. Pt films, ranging in thickness from 150Å to 1000Å, were prepared by sputter-deposition onto Si (100) blanket substrates or substrates patterned with windows of various sizes in SiO2. The samples were then annealed in a rapid thermal annealing system up to 550°C to form PtSi. The sheet resistance of silicide lines did not change significantly with linewidth. The thermal stability of the sheet resistance of PtSi was also measured for different linewidths and film thicknesses. The sheet resistance remained stable on annealing up to 850°C for a silicide film made of 250Å Pt and did not appear to be sensitive to the linewidth. The thickness dependence of the thermal stability of resistance was also evaluated.The stress of the silicide films was measured using a laser deflection system. The asdeposited metal films were under compressive stress, but the stress turned into tensile upon annealing when silicide started to form. After PtSi was formed, the stress remained stable with annealing temperature until approximately 900°C when the stress exhibited a sharp decrease. Unlike electrical conductance, however, the breakdown temperature for stress did not strongly depend on the film thickness.

A Correlation Study of Thermal Stability on Porous Low k

2002 ◽  
Vol 716 ◽  
Author(s):  
Y.F. Chow ◽  
T.H. Foo ◽  
L. Shen ◽  
J.S. Pan ◽  
A.Y. Du ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Dielectric Constant ◽  
Refractive Index ◽  
Annealing Temperature ◽  
Correlation Study ◽  
Film Properties ◽  
Unannealed Sample ◽  
Nano Indentation ◽  
Low K ◽  
Thermal Stability Of

AbstractThe thermal stability of organic porous low k, porous SiLK with a dielectric constant of 2.4, has been studied. Organic low k material SiLKTM, non-porous SiLK, with a dielectric constant 2.8 is used as a baseline for comparison. Each sample was subjected to annealing cycles, where each cycle was conducted in a vertical furnace for one hour in an N2 ambient. The annealing temperature was set at either 430°C or 450°C. After every alternate cycle, the film properties were measured and compared to the unannealed sample for changes in film shrinkage, refractive index, dielectric constant, roughness, breakdown voltage, pore size, hardness and Young's modulus. Changes in film properties were investigated and evaluated by using opti-probe, FTIR, XPS, AFM, mercury probe, nano-indentation, SEM and TEM techniques.

High thermal stability of block copolymer-capped Au and Cu nanoparticles

2014 ◽  
Vol 50 (80) ◽  
pp. 11919-11921 ◽  
Author(s):  
Iryna I. Perepichka ◽  
Mohamed A. Mezour ◽  
Dmitrii F. Perepichka ◽  
R. Bruce Lennox
Keyword(s):  
Thermal Stability ◽  
Block Copolymer ◽  
Block Copolymers ◽  
Metal Nanoparticles ◽  
High Temperatures ◽  
High Thermal Stability ◽  
Cu Nanoparticles ◽  
Prolonged Heating ◽  
Thermal Stability Of

Pyridine-containing block copolymers (PS-P4VP) can effectively stabilize metal nanoparticles which survive prolonged heating in solutions at high temperatures.

Thermal Stability of Cu Films on Tin/Ti/Si(100) by Partially Ionized Beam Deposition

1996 ◽  
Vol 438 ◽  
Author(s):  
H. G. Jang ◽  
K. H. Kim ◽  
D. J. Choi ◽  
S. Han ◽  
S. C. Choi ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Annealing Temperature ◽  
Rutherford Backscattering Spectrometry ◽  
Depth Profiling ◽  
Film Surface ◽  
Cu Films ◽  
Profiling Techniques ◽  
Partially Ionized ◽  
Thermal Stability Of ◽  
Beam Deposition

AbstractCu thin films with a thickness around 850 Å were prepared on Ti45N55/Ti/Si(100) substrates at room temperature by partially ionized beam deposition (PIBD) with an ion energy of 3 keV at pressure of 8×10−7-1 x 10−6 Torr. The Cu/Ti45N55/Ti/Si samples were annealed at 8×10−6-1 × 10−5 Torr with annealing temperature of 500 to 700 °C for 30 min.. Thermal stability of the PIB-Cu films was investigated with Rutherford backscattering spectrometry (RBS), Auger electron spectroscopy (AES), Scanning electron microscopy (SEM), and X-ray diffraction (XRD). The as deposited Cu films had a (111) texture and there was no change of phase in annealed Cu films regardless of annealing temperature. Grain size of the annealed Cu films increased with annealing temperature. SEM studies show no hillock and no voiding on the Cu film surface up to annealing temperature of 700 °C. For PIB-Cu/Ti45N55/Ti/Si samples, all the layers were intact and there was no indication of interdiffusion by conventional depth profiling techniques (RBS, AES) up to 700 °C in vacuum for 30 minutes.

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