scholarly journals Enhanced uptake of water by oxidatively processed oleic acid

2004 ◽  
Vol 4 (4) ◽  
pp. 4019-4038 ◽  
Author(s):  
A. Asad ◽  
B. T. Mmereki ◽  
D. J. Donaldson
Keyword(s):  
Thin Films ◽  
Oleic Acid ◽  
Relative Humidity ◽  
Gas Phase ◽  
Room Temperature ◽  
Quartz Crystal ◽  
Plateau Region ◽  
Polymeric Product ◽  
Partial Pressures ◽  
Additional Water

Abstract. A quartz crystal microbalance apparatus has been used to measure the room temperature uptake of water vapour by thin films of oleic acid as a function of relative humidity, both before and following exposure of the films to various partial pressures of gas phase ozone. A rapid increase in the water-sorbing ability of the film is observed as its exposure to ozone is increased, followed by a plateau region in which no additional water is taken up. In this fully-processed region the mass of water taken up by the film is about 4 times that of the unprocessed film. Infrared spectra of the films, measured after variable exposures to ozone, show dramatic increases in both the "free" and hydrogen-bonded O-H stretching regions, and a decrease in the intensity of olefinic features. These results are consistent with the formation of an oxygenated polymeric product or products, as well as the gas phase products previously identified.

scholarly journals Enhanced uptake of water by oxidatively processed oleic acid

2004 ◽  
Vol 4 (8) ◽  
pp. 2083-2089 ◽  
Author(s):  
A. Asad ◽  
B. T. Mmereki ◽  
D. J. Donaldson
Keyword(s):  
Thin Films ◽  
Oleic Acid ◽  
Relative Humidity ◽  
Gas Phase ◽  
Room Temperature ◽  
Quartz Crystal ◽  
Plateau Region ◽  
Polymeric Product ◽  
Partial Pressures ◽  
Additional Water

Abstract. A quartz crystal microbalance apparatus has been used to measure the room temperature uptake of water vapour by thin films of oleic acid as a function of relative humidity, both before and following exposure of the films to various partial pressures of gas phase ozone. A rapid increase in the water-sorbing ability of the film is observed as its exposure to ozone is increased, followed by a plateau region in which additional water is taken up more gradually. In this fully-processed region the mass of water taken up by the film is about 4 times that of the unprocessed film. Infrared spectra of the films, measured after variable exposures to ozone, show dramatic increases in both the "free" and hydrogen-bonded O-H stretching regions, and a decrease in the intensity of olefinic features. These results are consistent with the formation of an oxygenated polymeric product or products, as well as the gas phase products previously identified.

scholarly journals PECVD of Hexamethyldisiloxane Coatings Using Extremely Asymmetric Capacitive RF Discharge

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2147
Author(s):  
Žiga Gosar ◽  
Janez Kovač ◽  
Denis Đonlagić ◽  
Simon Pevec ◽  
Gregor Primc ◽  
...  
Keyword(s):  
Thin Films ◽  
Gas Phase ◽  
Discharge Chamber ◽  
Depth Profiling ◽  
Dust Particles ◽  
Rf Discharge ◽  
Plasma Parameters ◽  
Entire Volume ◽  
Partial Pressures ◽  
Pressure Discharge

An extremely asymmetric low-pressure discharge was used to study the composition of thin films prepared by PECVD using HMDSO as a precursor. The metallic chamber was grounded, while the powered electrode was connected to an RF generator. The ratio between the surface area of the powered and grounded electrode was about 0.03. Plasma and thin films were characterised by optical spectroscopy and XPS depth profiling, respectively. Dense luminous plasma expanded about 1 cm from the powered electrode while a visually uniform diffusing plasma of low luminosity occupied the entire volume of the discharge chamber. Experiments were performed at HMDSO partial pressure of 10 Pa and various oxygen partial pressures. At low discharge power and small oxygen concentration, a rather uniform film was deposited at different treatment times up to a minute. In these conditions, the film composition depended on both parameters. At high powers and oxygen partial pressures, the films exhibited rather unusual behaviour since the depletion of carbon was observed at prolonged deposition times. The results were explained by spontaneous changing of plasma parameters, which was in turn explained by the formation of dust in the gas phase and corresponding interaction of plasma radicals with dust particles.

scholarly journals Defects Induced Room Temperature Ferromagnetism in ZnO Thin Films

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Xiao Zhang ◽  
Wei Zhang ◽  
Xinghua Zhang ◽  
Xuewen Xu ◽  
Fanbin Meng ◽  
...  
Keyword(s):  
Thin Films ◽  
Oxygen Vacancy ◽  
Room Temperature ◽  
Magnetic Order ◽  
Room Temperature Ferromagnetism ◽  
Electronic Configuration ◽  
Zno Thin Films ◽  
Argon Gas ◽  
Pure Argon ◽  
Partial Pressures

Polycrystalline ZnO thin films are prepared by the co-sputtering method under different oxygen partial pressures. Films deposited in pure argon gas exhibit ferromagnetism, whereas other films deposited under different oxygen partial pressures are diamagnetism. XPS results show the presence of Zn interstitial and oxygen vacancy in all of samples. Further analysis indicates that Zn interstitial may play an important role in triggering magnetic order on the undoped ZnO thin films by inducing an alteration of electronic configuration.

Mass Thickness Analysis of Gold Thin Films Using Room Temperature Gas-Phase Chlorination

2009 ◽  
Vol 81 (8) ◽  
pp. 2877-2883 ◽  
Author(s):  
Alexander Vaskevich ◽  
Tali Sehayek ◽  
Israel Rubinstein
Keyword(s):  
Thin Films ◽  
Gas Phase ◽  
Room Temperature ◽  
Mass Thickness ◽  
Gold Thin Films

Humidity Sensitive Properties of Graphene Oxide Investigated by Quartz Crystal Microbalance

2014 ◽  
Vol 1051 ◽  
pp. 85-89 ◽  
Author(s):  
Hui Yao Yu ◽  
Ying Long Yao ◽  
Xiao Hua Wang
Keyword(s):  
Thin Film ◽  
Aqueous Solution ◽  
Graphene Oxide ◽  
Relative Humidity ◽  
Quartz Crystal Microbalance ◽  
Room Temperature ◽  
Quartz Crystal ◽  
Oxide Thin Film ◽  
Sensing Material ◽  
Maximum Humidity

Graphene oxide has been studied as sensing material for the humidity detection in this paper. At room temperature, graphene oxide was dissolved in water to prepare graphene oxide aqueous solution. This aqueous solution was distributed on the electrode surface of quartz crystal microbalance to form a thin film for humidity detection. The results of the experiment showed that the quartz crystal microbalance sensors with graphene oxide film have good response to the change of humidity. The maximum humidity sensitivity, during the humidity ranging from 10% to 90%RH (relative humidity), has achieved ~54Hz/%RH (relative humidity). The quartz crystal microbalance sensors with graphene oxide thin film have good stability and reproducibility properties. All results implied that the graphene oxide was a potential humidity sensing material for practical use.

Room Temperature Ferromagnetism in Ti0.985Co0.015O2-δ Thin Films Grown by Pulsed Laser Deposition Technique

2013 ◽  
Vol 760 ◽  
pp. 1-7 ◽  
Author(s):  
P. Mohanty ◽  
V. Ganeshan ◽  
Chandana Rath
Keyword(s):  
Thin Films ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Pulsed Laser Deposition ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Pulsed Laser ◽  
Phase Changes ◽  
Laser Deposition ◽  
Partial Pressures

Ti0.985Co0.015O2-δ thin films are deposited at 0, 0.1, 1 and 300 mTorr oxygen partial pressures by pulsed laser deposition (PLD) technique. Glancing angle x- ray diffraction (GAXRD) and micro-Raman spectroscopy show that the phase changes from rutile to anatase with increasing oxygen partial pressure. From Rutherford backscattering spectroscopic (RBS) technique, O to (Ti+Co) atomic ratio is found to increase with increasing oxygen partial pressure. Further, the simulation of RBS data while reveals non-uniform distribution of Co throughout the film deposited at 0 and 0.1 mTorr oxygen partial pressures, at 1 and 300 mTorr oxygen partial pressure, Co distribution is found to be uniform. Magnetic measurements confirm the room temperature ferromagnetism (RTFM) in all the films independent of the phase. Magnetic force microscopy (MFM) further supports the ferromagnetic nature of the films. We attribute the ferromagnetism in the films to be arisen from defects like oxygen vacancies rather than any contamination or Co clustering.

Studies on Water in the Hydration Chamber of a Modified Electron Microscope

1970 ◽  
Vol 28 ◽  
pp. 544-545
Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electron Microscope ◽  
Steady State ◽  
Room Temperature ◽  
Small Mass ◽  
Equilibrium Pressure ◽  
Biological Objects ◽  
Mechanical Pump ◽  
Differential Pumping

Use of the electron microscope to examine wet objects is possible due to the small mass thickness of the equilibrium pressure of water vapor at room temperature. Previous attempts to examine hydrated biological objects and water itself used a chamber consisting of two small apertures sealed by two thin films. Extensive work in our laboratory showed that such films have an 80% failure rate when wet. Using the principle of differential pumping of the microscope column, we can use open apertures in place of thin film windows.Fig. 1 shows the modified Siemens la specimen chamber with the connections to the water supply and the auxiliary pumping station. A mechanical pump is connected to the vapor supply via a 100μ aperture to maintain steady-state conditions.

Interactions Between Al and Cr Thin Films

1976 ◽  
Vol 34 ◽  
pp. 638-639
Author(s):  
R. M. Anderson ◽  
T. M. Reith ◽  
M. J. Sullivan ◽  
E. K. Brandis
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Vacuum System ◽  
Processing Temperature ◽  
Diffusion Couples ◽  
Electronic Circuits ◽  
Intermetallic Formation ◽  
Si Substrates ◽  
Aluminum Silicon

Thin films of aluminum or aluminum-silicon can be used in conjunction with thin films of chromium in integrated electronic circuits. For some applications, these films exhibit undesirable reactions; in particular, intermetallic formation below 500 C must be inhibited or prevented. The Al films, being the principal current carriers in interconnective metal applications, are usually much thicker than the Cr; so one might expect Al-rich intermetallics to form when the processing temperature goes out of control. Unfortunately, the JCPDS and the literature do not contain enough data on the Al-rich phases CrAl7 and Cr2Al11, and the determination of these data was a secondary aim of this work.To define a matrix of Cr-Al diffusion couples, Cr-Al films were deposited with two sets of variables: Al or Al-Si, and broken vacuum or single pumpdown. All films were deposited on 2-1/4-inch thermally oxidized Si substrates. A 500-Å layer of Cr was deposited at 120 Å/min on substrates at room temperature, in a vacuum system that had been pumped to 2 x 10-6 Torr. Then, with or without vacuum break, a 1000-Å layer of Al or Al-Si was deposited at 35 Å/s, with the substrates still at room temperature.

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