Adhesive Property Enhancement by Photochemical Modification on Polyimide Sheet Surface by Irradiation with Excimer Lamp

1995 ◽  
Vol 397 ◽  
Author(s):  
T. Okamoto ◽  
K. Hatao ◽  
T. Shimizu ◽  
M. Aoike ◽  
M. Murahara
Keyword(s):  
Water Solution ◽  
Pure Water ◽  
Fused Silica ◽  
Oh Radicals ◽  
Hydrogen Atoms ◽  
Excimer Lamp ◽  
Hydrophilic Property ◽  
Sheet Surface ◽  
Modified Surface ◽  
Photochemical Modification

ABSTRACTPolyimide sheet surface was photochemically modified to be hydrophilic property with Xe2* excimer lamp ( λ =172nm) irradiation and pure water solution. The solution was sandwiched between the surface and fused silica glass. With the excimer lamp irradiation, the solution and the surface were excited; the surface was dehydrogenated by the hydrogen atoms which were photodissociated from pure water and replaced the photodissociated OH radicals. The hydrophilic property of the modified surface was evaluated by measuring the contact angle with water. The replacement of the OH radicals were confirmed by FTIR. The modified surface was bonded to stainless steel with an epoxy resin for evaluation of the adhesive strength by the shearing tensile test. As a result, the adhesion was increased to 1.4 times that of the non-irradiated sample.

Open Air Fabrication of Al2O3 Thin Films at Room Temperature

1996 ◽  
Vol 451 ◽  
Author(s):  
T. Okamoto ◽  
K. Toyoda ◽  
M. Murahara
Keyword(s):  
Excimer Laser ◽  
Pure Aluminum ◽  
Fused Silica ◽  
Active Oxygen ◽  
Aluminum Substrate ◽  
Entrance Window ◽  
Excimer Lamp ◽  
Before And After ◽  
Modified Surface ◽  
Fused Silica Glass

ABSTRACTA thin layer of water or hydrogen peroxide solution, which was formed on a pure aluminum substrate, was photodissociated by ArF excimer laser( λ =193nm) or Xe2* excimer lamp (λ = 172nm) light to photochemically oxidize the surface of aluminum substrate. The layer was formed by a capillary phenomenon between the substrate and a fused silica glass as an entrance window of ultraviolet light. Then, the layer was photodissociated by the excimer laser or the excimer lamp light irradiation to generate active oxygen; the surface oxidization was performed by the photo-induced active oxygen. The surface before and after modification was evaluated by the XPS analysis; the high densed photo-oxidization film was confirmed on the modified surface, compared with a natural oxidization film Furthermore, the contact angle with water became remarkably small, and it is seen that the treated surface was quite densely oxidized.

Photochemical Modification of Fluorocarbon Resin Surface to Adhere with Epoxy Resin

1993 ◽  
Vol 334 ◽  
Author(s):  
M. Okoshi ◽  
T. Miyokawa ◽  
H. Kashiura ◽  
M. Murahara
Keyword(s):  
Tensile Test ◽  
Adhesive Strength ◽  
Photochemical Reaction ◽  
Water Solution ◽  
Surface Region ◽  
Oh Radicals ◽  
Near Surface ◽  
Modification Process ◽  
Arf Excimer Laser ◽  
Photochemical Modification

AbstractAn epoxy-compatible layer was produced in the near-surface region of a fluorocarbon resin by irradiating with an ArF excimer laser in a gaseous B(CH3)3 or a B(OH)3 water solution atmosphere. The pure photochemical reaction was employed in the modification process, the defluorination of the surface was performed with boron atoms which were photo-dissociated from B(CH3)3 or B(OH)3. The CH3 or OH radicals, also photo-dissociated, replaced the fluorine atoms of the surface. As a result, chemical bonding of the surface with the epoxy was performed. The adhesive strength was evaluated by the shearing tensile test, and the epoxy break value of 130 kgf/cm2 was sucessfully achieved.

Krf Excimer Laser Induced Photochemical Modification of Polyphenylenesulfide Surface Into Hydrophilic Property

1993 ◽  
Vol 334 ◽  
Author(s):  
H. Kashiura ◽  
M. Okoshi ◽  
M. Murahara
Keyword(s):  
Formic Acid ◽  
Excimer Laser ◽  
Laser Light ◽  
Carboxyl Groups ◽  
Hydrogen Atoms ◽  
Acid Vapor ◽  
Dehydrogenation Reaction ◽  
Hydrophilic Property ◽  
Krf Excimer Laser ◽  
Photochemical Modification

AbstractCarboxyl groups were photochemically substituted for hydrogen atoms at a polyphenylenesulfide surface by using an KrF excimer laser light and vaporized formic acid. In the process, the polyphenylenesulfide film was placed in the formic acid vapor, and the surface was irradiated with the KrF excimer laser light. Irradiating with the laser, the surface was dehydrogenated by the hydrogen atoms which were photodissociated from the formic acid; the dangling bonds on the surface combined with the COOH radicals which were also photodissociated. The hydrophilic property of the photomodified surface was evaluated by the measurement of the contact angle with water. The dehydrogenation reaction and the substitution reaction of the COOH radicals were inspected by XPS analysis. Surface morphology of the sample was observed by SEM photograph.

Association of Graft Copolymers of Alkyl Methacrylates with α-Methyl-ω-hydroxy-poly(oxyethylene) ethacrylates

1995 ◽  
Vol 60 (11) ◽  
pp. 1971-1985 ◽  
Author(s):  
Čestmír Koňák ◽  
Zdeněk Tuzar ◽  
Pavla Kopečková ◽  
Joseph D. Andrade ◽  
Jindřich Kopeček
Keyword(s):  
Light Scattering ◽  
Graft Copolymers ◽  
Water Solution ◽  
Pure Water ◽  
Solution Properties ◽  
Monomer Composition ◽  
Special Procedure ◽  
Methyl Cellosolve ◽  
Hexyl Methacrylate ◽  
Alkyl Methacrylates

Solution properties of the statistical copolymers of alkyl methacrylates (AMA) with α-methyl-ω-hydroxy-poly(oxyethylene) methacrylates (MPOEMA) (nonionic polysoaps) were studied using static and dynamic ligh scattering as a function of monomer composition and concentration in aqueous and methyl cellosolve solutions. The solubility of the copolymers in water was found to be dependent on molar contant of AMA. While copolymers with low content of hexyl methacrylate (HMA) (0 and 20 mole %) were directly soluble in water, forming true solutions with a low content of large swollen aggregates, copolymers with a higher content of HMA or lauryl methacrylate (LMA) were not directly dispersable in water. A special procedure, the stepwise dialysis from methyl cellosolve solutions against water, had to be used to prepare them in the pseudomicellar form. The copolymers were directly soluble in methyl cellosolve and its water solution containing up to 60 vol.% of water. Nevertheless, the light scattering experiments were dominated by light scattering of swollen particles of aggregated copolymer molecules. The copolymers were not soluble in the mixtures containing 70-100 vol.% of water. Paramaters of aggregates in the mixture with 60 vol.% of water and in pure water were found to be very similar.

scholarly journals Behavior and properties of water in silicate melts under deep mantle conditions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bijaya B. Karki ◽  
Dipta B. Ghosh ◽  
Shun-ichiro Karato
Keyword(s):  
Electrical Conductivity ◽  
Molar Volume ◽  
Water Solution ◽  
Pure Water ◽  
Electrical Conductance ◽  
Water Structure ◽  
Bulk Water ◽  
Silicate Melts ◽  
Pressure Regime ◽  
Low Pressures

AbstractWater (H2O) as one of the most abundant fluids present in Earth plays crucial role in the generation and transport of magmas in the interior. Though hydrous silicate melts have been studied extensively, the experimental data are confined to relatively low pressures and the computational results are still rare. Moreover, these studies imply large differences in the way water influences the physical properties of silicate magmas, such as density and electrical conductivity. Here, we investigate the equation of state, speciation, and transport properties of water dissolved in Mg1−xFexSiO3 and Mg2(1−x)Fe2xSiO4 melts (for x = 0 and 0.25) as well as in its bulk (pure) fluid state over the entire mantle pressure regime at 2000–4000 K using first-principles molecular dynamics. The simulation results allow us to constrain the partial molar volume of the water component in melts along with the molar volume of pure water. The predicted volume of silicate melt + water solution is negative at low pressures and becomes almost zero above 15 GPa. Consequently, the hydrous component tends to lower the melt density to similar extent over much of the mantle pressure regime irrespective of composition. Our results also show that hydrogen diffuses fast in silicate melts and enhances the melt electrical conductivity in a way that differs from electrical conduction in the bulk water. The speciation of the water component varies considerably from the bulk water structure as well. Water is dissolved in melts mostly as hydroxyls at low pressure and as –O–H–O–, –O–H–O–H– and other extended species with increasing pressure. On the other hand, the pure water behaves as a molecular fluid below 15 GPa, gradually becoming a dissociated fluid with further compression. On the basis of modeled density and conductivity results, we suggest that partial melts containing a few percent of water may be gravitationally trapped both above and below the upper mantle-transition region. Moreover, such hydrous melts can give rise to detectable electrical conductance by means of electromagnetic sounding observations.

scholarly journals Testing for ion-mediated enhancement of the hydraulic conductance of the leaf xylem in diverse angiosperms

2017 ◽  
Vol 4 ◽  
pp. e004 ◽  
Author(s):  
Christine Scoffoni ◽  
Grace John ◽  
Herve Cochard ◽  
Lawren Sack
Keyword(s):  
Water Solution ◽  
Pure Water ◽  
Xylem Sap ◽  
Hydraulic Conductance ◽  
Membrane Pores ◽  
Whole Plant ◽  
Pit Membrane ◽  
Major Bottleneck ◽  
The Difference ◽  
Xylem Conduits

Replacing ultra-pure water solution with ion solution closer to the composition of natural xylem sap increases stem hydraulic conductance by up to 58%, likely due to changes in electroviscosity in the pit membrane pores. This effect has been proposed to contribute to the control of plant hydraulic and stomatal conductance and potentially to influence on carbon balance during dehydration. However, this effect has never been directly tested for leaf xylem, which constitutes a major bottleneck in the whole plant. We tested for an ion-mediated increase in the hydraulic conductance of the leaf xylem (Kx) for seven species diverse in phylogeny and drought tolerance. Across species, no significant changes in Kx were observed between 0 and 15 mM KCl. We further tested for an effect of ion solution during measurements of Kx vulnerability to dehydration in Quercus agrifolia and found no significant impact. These results for leaf xylem contrast with the often strong ion effect reported for stems, and we suggest several hypotheses to account for the difference, relating to the structure of xylem conduits across vein orders, and the ultrastructure of leaf xylem pores. A negligible ion response in leaves would weaken xylem sap ion-mediated control of plant hydraulic conductance, facilitating modeling of whole plant hydraulic behavior and its influence on productivity.

Photochemical Bonding of Fluorocarbon and Fused Silica Glass for Ultraviolet Ray Transmitting

2003 ◽  
Vol 796 ◽  
Author(s):  
Kenji Asano ◽  
Masataka Murahara
Keyword(s):  
Tensile Strength ◽  
Silica Glass ◽  
Silicone Oil ◽  
Unsaturated Polyester ◽  
Fused Silica ◽  
Strong Absorption Band ◽  
Excimer Lamp ◽  
Silicon Oil ◽  
Fused Silica Glass ◽  
Uv Rays

ABSTRACTFluorocarbon was photo-chemically combined to a fused silica glass with the silicon oil used as a bonding agent. Balsam, unsaturated polyester resins and UV hardening adhesives have been generally used for joining two optical glasses together. They, however, have a strong absorption band in the UV region. Therefore, a new bonding method was developed for optical materials to allow UV rays to pass through using silicone oil and excimer- lamp. This new method requires the fluorocarbon-polishing pad employed in our PCP (Photo-Chemical Polishing) method in hydrofluoric acid ambience, which is bonded with the silica glass. The silicone oil was put between the fused silica glass and the fluorocarbon (FEP), and an excimer- lamp was irradiated. When the excimer lamplight was irradiated vertically, the silicon oil ((-O-Si(CH3)-O-)n) was photo-dissociated and reacted with the oxygen adsorbed on the silica glass surface to produce a SiO2. On the other hand, the H atoms photo-dissociated from the silicon oil pulled out the F atoms of the FEP. As a result, the FEP and the silica glass were combined. The tensile strength of the sample bonded by the photo-chemical reaction was evaluated. The tensile strength of 5.4 [kgf/cm2] was obtained, whereas that of the non-treatment sample was nil. Moreover, the transmittance of the vitrified silicone oil was measured at the 193 nm of ArF laser wavelength. It increased by 90.6% from 29.2% without the UV photon irradiation. The results showed that the silicon oil changed to silica glass by the excited oxygen, which improved the UV rays under 200nm transmittance.

Hydrometallurgical thermodynamics. I. Effect of sulfate ion-pairing and ion-solvation on the copper-iron redox equilibrium in aqueous acetonitrile

1983 ◽  
Vol 36 (9) ◽  
pp. 1687 ◽  
Author(s):  
BW Clare ◽  
P Singh ◽  
P Mangano ◽  
AJ Parker ◽  
DM Muir
Keyword(s):  
Water Solution ◽  
Pure Water ◽  
Ion Pairing ◽  
Ion Solvation ◽  
Sulfate Ion ◽  
Redox Equilibrium ◽  
Small Shift ◽  
Enthalpy Changes ◽  
The Right ◽  
Iron Redox

The copper-iron redox equilibrium is shifted to the right CuII+FeII↔CuI+FeIII by strong ion-pairing of sulfate ion with FeIII and by specific solvation of CuI with acetonitrile. The equilibrium constant has been measured by direct e.m.f. and spectroscopic methods between pH 0-2 and found to be about 107 higher for practical solutions of sulfates in acetonitrile/water than that calculated for perchlorates in pure water. Enthalpies and free energies of transfer of these ions from water to acetonitrile/water show that the shift in equilibrium to Cul+FeIII in acetonitrile/water solution is strongly favoured by enthalpy changes associated with copper(I)-acetonitrile ion-solvation. Ion-pairing of sulfate ion with iron(III) results in an increase in entropy and a small shift of the equilibrium to the right.

Activation Energy for Strength Degradation of Fused Silica Optical Fibers

1998 ◽  
Vol 531 ◽  
Author(s):  
Yunn-Shin Shiue ◽  
M. John Matthewson
Keyword(s):  
Activation Energy ◽  
Optical Fibers ◽  
Pure Water ◽  
Strength Degradation ◽  
Fused Silica ◽  
Static Fatigue ◽  
Buffer Solution ◽  
Silica Fibers ◽  
Apparent Activation Energies ◽  
Stress Dependent

AbstractThe strength degradation behavior of fused silica optical fiber is well known to be sensitive to the temperature and an apparent activation energy can be determined. In addition, it has been observed that the activation energy also depends on the applied stress and the nature of the environment. However, no consistent model for this behavior has emerged. We propose a chemical kinetics model which accounts for the temperature dependence of the dissociation of water which predicts that degradation should be faster in pH 7 buffer than in pure water. Static fatigue of fused silica fibers in both water and pH 7 buffer solution has been carefully studied as a function of temperature to test the model. The apparent activation energies are stress dependent, and, while the dependency is not clear, different environments give different dependencies. These observations support the proposed model.

The application of resonance enhanced multiphoton ionization to the detection of hydrogen atoms during the oscillatory combustion of hydrogen

1991 ◽  
Vol 434 (1891) ◽  
pp. 399-412 ◽  
Keyword(s):  
Numerical Analysis ◽  
Flow Reactor ◽  
Multiphoton Ionization ◽  
Laser Wavelength ◽  
Time Profile ◽  
Experimental Result ◽  
Oh Radicals ◽  
Hydrogen Atoms ◽  
Experimental Conditions ◽  
Concentration Time

The relative concentrations of hydrogen atoms were measured during the oscillatory ignition of hydrogen in a well stirred flow reactor. Comparisons were made with the experimental concentration—time profiles of the hydroxyl radical obtained previously under similar experimental conditions. The predicted concentration profiles obtained from numerical analysis of a thermokinetic model were also compared with the experimental results. Experiments were performed in a 600 cm 3 Pyrex glass, jet-stirred reactor with the reactants, 2H 2 + O 2 , at a total pressure of 16 Torr ( ca . 2132.8 Pa) and at a vessel temperature of 753 K. The mean residence time was 1.2 s. Oscillatory ignition was established at a period of 3 s in which high radical concentrations were attained and in which the temperature rise was almost adiabatic. The concentration-time profile of hydrogen atoms was obtained by a resonance enhanced multiphoton ionization (rempi) which was induced by a laser pulse at energies in the vicinity of 364 nm, with ion collection at a stainless steel probe inserted into the reactor. Supplementary studies were made to characterize the signals and to identify effects of the probe within the reaction volume. A measurement of the relative concentrations of hydrogen atoms was obtained from an integration of the area of the rempi spectrum determined over the laser wavelength range 363.8-364.6 nm. The spectrum was measured at successive times in the oscillatory cycle by imposing a variable delay on the laser firing signal. The results show that, during oscillatory ignition, the maximum concentration of hydrogen atoms was reached and a sharp decay was already well advanced before that of the hydroxyl radicals was attained. The numerical analysis was in very good quantitative accord with this experimental result. The phase difference of the cyclic variation in the H atoms relative to that of OH radicals is a key feature of the kinetic mechanisms which control the oscillatory oxidation of hydrogen.

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