Science.gov

Sample records for fluorocarbons

  1. PRODUCTION OF FLUOROCARBONS

    DOEpatents

    Sarsfield, N.F.

    1949-06-21

    This patent pertains to a process for recovering fluorocarbons from a liquid mixture of hydrocarbons with partially and completely fluorinated products thereof. It consists of contacting the mxture in the cold with a liquid which is a solvent for the hydrocarbons and which is a nonsolvent for the fluorocarbons, extracting the hydrocarbons, separating the fluorocarbon-containing layer from the solvent-containing layer, and submitting the fluorocarbon layer to fractlonal distillation, to isolate the desired fluorocarbon fraction. Suitable solvents wnich may be used in the process include the lower aliphatic alcohols, and the lower aliphatic ketones.

  2. Fluorocarbons: properties and syntheses.

    PubMed

    Dixon, D D; Holland, D G

    1975-05-01

    The paper discusses custom syntheses of fluorocarbons for potential use as artificial blood substitutes. The term "fluorocarbon" designates a perfluorinated carbon compound which does not contain another halogen or hydrogen. Prominent requirements of an artificial blood substitute are: 1) efficient oxygen/carbon dioxide transport, 2) biological inertness, 3) low vapor pressure, 4) dispersibility to form emulsion. Fluorocarbons are superior to other liquids in dissolving oxygen and carbon dioxide. The most biologically inert halogenated alkanes are fully fluorinated. Introduction of another halogen or unsaturation decreases biological inertness. Boiling points of fluoroalkanes can be estimated from the Kinney equation. The most common method of fluorination, namely electrofluorination, is briefly described and applied to several types of organic compounds. Hydrocarbons give low yields of perfluoroalkanes. Alternatively, perfluoroalkanes may be prepared through reaction of functionalized substrates. Innert perfluorocyclic ethers are obtained from substrate ethers or acid fluorides. All types of amines perfluorinate but only perfluorotertiary amines are inert. Divalent organo-sulfur compounds afford inert perfluorinated products with sulfur in the hexavalent state. Sulfonyl fluorides give perfluorosulfonyl fluorides which can be pyrolytically coupled producing perfluoroalkanes. The Schoniger combustion method and neutron activation are described as analytical means for determining fluorine content. PMID:1126440

  3. water-soluble fluorocarbon coating

    NASA Technical Reports Server (NTRS)

    Nanelli, P.

    1979-01-01

    Water-soluble fluorocarbon proves durable nonpolluting coating for variety of substrates. Coatings can be used on metals, masonry, textiles, paper, and glass, and have superior hardness and flexibility, strong resistance to chemicals fire, and weather.

  4. Hexafluorobenzene photochemistry: wellspring of fluorocarbon structures.

    PubMed

    Lemal, D M

    2001-08-01

    Ultraviolet irradiation of hexafluorobenzene in the vapor phase gives exclusively its Dewar valence isomer, from which a wealth of highly fluorinated compounds has been derived. Photoexcited in solution, hexafluorobenzene is capable of cycloaddition with a variety of unsaturated molecules. Like the Dewar benzene, resulting adducts have served as intermediates en route to many new fluorocarbons and fluorocarbon derivatives. PMID:11513574

  5. Fluorinated diamond bonded in fluorocarbon resin

    DOEpatents

    Taylor, Gene W. (Los Alamos, NM)

    1982-01-01

    By fluorinating diamond grit, the grit may be readily bonded into a fluorocarbon resin matrix. The matrix is formed by simple hot pressing techniques. Diamond grinding wheels may advantageously be manufactured using such a matrix. Teflon fluorocarbon resins are particularly well suited for using in forming the matrix.

  6. Extending TEWI to production of fluorocarbons

    SciTech Connect

    Banks, R.E.; Sharratt, P.N.; Johnson, E.P.; Clarke, E.K.

    1996-12-31

    In many analyses of Total Environment Warming Impact (TEWI) that involve fluorocarbons, the release of the end-product fluorocarbon to atmosphere--for instance, venting from a used refrigeration unit--is the only global warming that is considered. For fluorochemicals where the end-product is not even a global warmer itself, production may be the stage of the life-cycle where global warming is greatest. Thus, a TEWI comparison of two systems involving fluorocarbons that ignores the production stage may be inaccurate. This paper illustrates the above in three parts: (1) An overview of fluorocarbon manufacturing, focusing on key global warmers; (2) a closer, step-by-step examination of the manufacturing chain for hexafluoropropene (HFP), with quantification of the global warmers and ozone depletors emitted; and (3) presentation of the TEWI calculations and results for HFP, split into two types of contributions: (1) fluorocarbon and (2) energy/transport.

  7. Electron attachment to fluorocarbon radicals

    NASA Astrophysics Data System (ADS)

    Shuman, Nicholas

    2014-10-01

    Most plasma environments contain populations of short-lived species such as radicals, the chemistry of which can have significant effects on the overall chemistry of the system. However, few experimental measurements of the kinetics of electron attachment to radicals exist due to the inherent difficulties of working with transient species. Calculations from first principles have been attempted, but are arduous and, because electron attachment is so sensitive to the specifics of the potential surface, their accuracy has not been established. Electron attachment to small fluorocarbon radicals is particularly important, as the data are needed for predictive modeling of plasma etching of semiconductor materials, a key process in the industrial fabrication of microelectronics. We have recently developed a novel flowing afterglow technique to measure several types of otherwise difficult to study plasma processes, including thermal electron attachment to radicals. Variable Electron and Neutral Density Attachment Mass Spectrometry (VENDAMS) exploits dissociative electron attachment in a weakly ionized plasma as a radical source. Here, we apply VENDAMS to a series of halofluorocarbon precursors in order to measure the kinetics of thermal electron attachment to fluorocarbon radicals. Results are presented for CF2, CF3, C2F5,C2F3,1-C3F7, 2-C3F7, and C3F5 from 300 K to 900 K. Both the magnitude and the temperature dependences of rate coefficients as well as product branching between associative and dissociative attachment are highly system specific; however, thermal attachment to all species is inefficient, never exceeding 5% of the collision rate. The data are analyzed using a recently developed kinetic modeling approach, which uses extended Vogt-Wannier theory as a starting point, accounts for dynamic effects such as coupling between the electron and nuclear motions through empirically validated functional forms, and finally uses statistical theory to determine the fate of the highly excited anion intermediate formed during attachment. The kinetic modeling, along with complimentary data from electron beam measurements, is used to extrapolate the electron attachment rate coefficients to temperature and pressure regimes inaccessible to the experiment, including to non-thermal plasma conditions most relevant to plasma etching.

  8. Fluorocarbon Adsorption in Hierarchical Porous Frameworks

    SciTech Connect

    Motkuri, Radha K.; Annapureddy, Harsha V.; Vijayakumar, M.; Schaef, Herbert T.; Martin, P F.; McGrail, B. Peter; Dang, Liem X.; Krishna, Rajamani; Thallapally, Praveen K.

    2014-07-09

    The adsorption behavior of a series of fluorocarbon derivatives was examined on a set of microporous metal organic framework (MOF) sorbents and another set of hierarchical mesoporous MOFs. The microporous M-DOBDC (M = Ni, Co) showed a saturation uptake capacity for R12 of over 4 mmol/g at a very low relative saturation pressure (P/Po) of 0.02. In contrast, the mesoporous MOF MIL-101 showed an exceptionally high uptake capacity reaching over 14 mmol/g at P/Po of 0.4. Adsorption affinity in terms of mass loading and isosteric heats of adsorption were found to generally correlate with the polarizability of the refrigerant with R12 > R22 > R13 > R14 > methane. These results suggest the possibility of exploiting MOFs for separation of azeotropic mixtures of fluorocarbons and use in eco-friendly fluorocarbon-based adsorption cooling and refrigeration applications.

  9. A unique type of fluorocarbon elastomer

    SciTech Connect

    Eggers, R.E.

    1991-06-01

    This article examines the mechanical and chemical properties of the fluorocarbon elastomer Aflas tetrafluoroethylene (TFE/P) based on the monomers tetrafluoroethylene (TFE) and propylene (P). Topics discussed include TFE/P elastomer products, compounding TFE/P elastomers, polymer selection, reinforcing fillers, peroxide vulcanizing agents, coagents, process aids, processing TFE/P elastomers, and applications for the use of TFE/P elastomers.

  10. Fluorocarbon nanodrops as acoustic temperature probes.

    PubMed

    Mountford, Paul A; Smith, William S; Borden, Mark A

    2015-10-01

    This work investigated the use of superheated fluorocarbon nanodrops for ultrasound thermal imaging and the use of mixed fluorocarbons for tuning thermal and acoustic thresholds for vaporization. Droplets were fabricated by condensing phospholipid-coated microbubbles containing C3F8 and C4F10 mixed at various molar ratios. Vaporization temperatures first were measured in a closed system by optical transmission following either isothermal pressure release or isobaric heating. The vaporization temperature was found to depend linearly on the percentage of C4F10 in the droplet core, indicating excellent tunability under these fluorocarbon-saturated conditions. Vaporization temperatures were then measured in an open system using contrast-enhanced ultrasound imaging, where it was found that the mixed droplets behaved like pure C4F10 drops. Additionally, the critical mechanical index for vaporization was measured at the limits of therapeutic hyperthermia (37 and 60 C), and again the mixed droplets were found to behave like pure C4F10 drops. These results suggested that C3F8 preferentially dissolves out of the droplet core in open systems, as shown by a simple mass transfer model of multicomponent droplet dissolution. Finally, proof-of-concept was shown that pure C4F10 nanodrops can be used as an acoustic temperature probe. Overall, these results not only demonstrate the potential of superheated fluorocarbon emulsions for sonothermetry but also point to the limits of tunability for fluorocarbon mixtures owing to preferential release of the more soluble species to the atmosphere. PMID:26359919

  11. Fluorocarbon adsorption in hierarchical porous frameworks.

    PubMed

    Motkuri, Radha Kishan; Annapureddy, Harsha V R; Vijaykumar, M; Schaef, H Todd; Martin, Paul F; McGrail, B Peter; Dang, Liem X; Krishna, Rajamani; Thallapally, Praveen K

    2014-01-01

    Metal-organic frameworks comprise an important class of solid-state materials and have potential for many emerging applications such as energy storage, separation, catalysis and bio-medical. Here we report the adsorption behaviour of a series of fluorocarbon derivatives on a set of microporous and hierarchical mesoporous frameworks. The microporous frameworks show a saturation uptake capacity for dichlorodifluoromethane of >4?mmol?g(-1) at a very low relative saturation pressure (P/Po) of 0.02. In contrast, the mesoporous framework shows an exceptionally high uptake capacity reaching >14?mmol?g(-1) at P/Po of 0.4. Adsorption affinity in terms of mass loading and isosteric heats of adsorption is found to generally correlate with the polarizability and boiling point of the refrigerant, with dichlorodifluoromethane > chlorodifluoromethane > chlorotrifluoromethane > tetrafluoromethane > methane. These results suggest the possibility of exploiting these sorbents for separation of azeotropic mixtures of fluorocarbons and use in eco-friendly fluorocarbon-based adsorption cooling. PMID:25006832

  12. Fluorocarbon adsorption in hierarchical porous frameworks

    SciTech Connect

    Motkuri, RK; Annapureddy, HVR; Vijaykumar, M; Schaef, HT; Martin, PF; McGrail, BP; Dang, LX; Krishna, R; Thallapally, PK

    2014-07-09

    Metal-organic frameworks comprise an important class of solid-state materials and have potential for many emerging applications such as energy storage, separation, catalysis and bio-medical. Here we report the adsorption behaviour of a series of fluorocarbon derivatives on a set of microporous and hierarchical mesoporous frameworks. The microporous frameworks show a saturation uptake capacity for dichlorodifluoromethane of >4 mmol g(-1) at a very low relative saturation pressure (P/P-o) of 0.02. In contrast, the mesoporous framework shows an exceptionally high uptake capacity reaching >14 mmol g(-1) at P/P-o of 0.4. Adsorption affinity in terms of mass loading and isosteric heats of adsorption is found to generally correlate with the polarizability and boiling point of the refrigerant, with dichlorodifluoromethane >chlorodifluoromethane >chlorotrifluoromethane >tetrafluoromethane >methane. These results suggest the possibility of exploiting these sorbents for separation of azeotropic mixtures of fluorocarbons and use in eco-friendly fluorocarbon-based adsorption cooling.

  13. Blood fluorocarbon levels following exposure to household aerosols *

    PubMed Central

    Marier, G.; MacFarland, H.; Wiberg, G. S.; Buchwald, H.; Dussault, P.

    1974-01-01

    Measurement of blood fluorocarbon levels was carried out in subjects exposed to a number of household aerosol products containing fluorocarbon gases as propellants. All aerosols were used according to manufacturers' recommendations. The general purpose of the study was to determine whether with normal routine exposure to a wide variety of household aerosol products fluorocarbon could be found in the blood and if so, to check the potential toxicity of the levels reached. Daily exposure to aerosols according to the study regimen lasted four consecutive weeks; this period was preceded and followed by two weeks of abstention from exposure. At the end of each of the three periods a medical examination, including evaluation of cardiac function, respiratory function studies, and hematological and functional clinical biochemical tests was performed. All tests and assessments failed to show any indication of toxicity. No trace of fluorocarbon was found in any of the blood sampled at intervals during the study. PMID:4841238

  14. Decontamination by cleaning with fluorocarbon surfactant solutions

    SciTech Connect

    Kaiser, R.; Benson, C.E.; Meyers, E.S.; Vaughen, V.C.A.

    1994-02-01

    In the nuclear industry, facilities and their components inevitably become contaminated with radioactive materials. This report documents the application of a novel particle-removal process developed by Entropic Systems, Inc. (ESI), to decontaminate critical instruments and parts that are contaminated with small radioactive particles that adhere to equipment surfaces. The tests were performed as a cooperative effort between ESI and the Chemical Technology Division of the Oak Ridge National Laboratory (ORNL). ESI developed a new, environmentally compatible process to remove small particles from solid surfaces that is more effective than spraying or sonicating with CFC-113. This process uses inert perfluorinated liquids as working media; the liquids have zero ozone-depleting potential, are nontoxic and nonflammnable, and are generally recognized as nonhazardous materials. In the ESI process, parts to be cleaned are first sprayed or sonicated with a dilute solution of a high-molecular-weight fluorocarbon surfactant in an inert perfluorinated liquid to effect particle removal. The parts are then rinsed with the perfluorinated liquid to remove the fluorocarbon surfactant applied in the first step, and the residual rinse liquid is then evaporated from the parts into an air or nitrogen stream from which it is recovered. Nuclear contamination is inherently a surface phenomenon. The presence of radioactive particles is responsible for all ``smearable`` contamination and, if the radioactive particles are small enough, for some of the fixed contamination. Because radioactivity does not influence the physical chemistry of particle adhesion, the ESI process should be just as effective in removing radioactive particles as it is in removing nonradioactive particles.

  15. Fluorinated diamond particles bonded in a filled fluorocarbon resin matrix

    DOEpatents

    Taylor, G.W.; Roybal, H.E.

    1983-11-14

    A method of producing fluorinated diamond particles bonded in a filled fluorocarbon resin matrix. Simple hot pressing techniques permit the formation of such matrices from which diamond impregnated grinding tools and other articles of manufacture can be produced. Teflon fluorocarbon resins filled with Al/sub 2/O/sub 3/ yield grinding tools with substantially improved work-to-wear ratios over grinding wheels known in the art.

  16. Fluorinated diamond particles bonded in a filled fluorocarbon resin matrix

    DOEpatents

    Taylor, Gene W. (Los Alamos, NM); Roybal, Herman E. (Santa Fe, NM)

    1985-01-01

    A method of producing fluorinated diamond particles bonded in a filled fluorocarbon resin matrix. Simple hot pressing techniques permit the formation of such matrices from which diamond impregnated grinding tools and other articles of manufacture can be produced. Teflon fluorocarbon resins filled with Al.sub.2 O.sub.3 yield grinding tools with substantially improved work-to-wear ratios over grinding wheels known in the art.

  17. Fluorocarbon compounds in MRI diagnostics and medical therapy

    NASA Astrophysics Data System (ADS)

    Pirogov, Yu

    2016-02-01

    The lecture describes the application of fluorocarbon compounds as blood substitutes and contrasting preparations in MRI diagnostics. A blood substitute product fluorocarbon Perfluorane® has shown effectiveness in oxygen delivery to the tissues of living organisms, and cardioprotective effect which does not depend on the patient's blood group. Inclusion of paramagnetic atoms (gadolinium, iron, etc.) to the Perfluorane® chemical formula creates a new compound with high MRI contrast efficiencies at Larmor frequencies of protons so and fluorine-19 nuclei.

  18. Thermodynamic properties of gaseous fluorocarbons and isentropic equilibrium expansions of two binary mixtures of fluorocarbons and argon

    NASA Technical Reports Server (NTRS)

    Talcott, N. A., Jr.

    1977-01-01

    Equations and computer code are given for the thermodynamic properties of gaseous fluorocarbons in chemical equilibrium. In addition, isentropic equilibrium expansions of two binary mixtures of fluorocarbons and argon are included. The computer code calculates the equilibrium thermodynamic properties and, in some cases, the transport properties for the following fluorocarbons: CCl2F, CCl2F2, CBrF3, CF4, CHCl2F, CHF3, CCL2F-CCl2F, CCLF2-CClF2, CF3-CF3, and C4F8. Equilibrium thermodynamic properties are tabulated for six of the fluorocarbons(CCl3F, CCL2F2, CBrF3, CF4, CF3-CF3, and C4F8) and pressure-enthalpy diagrams are presented for CBrF3.

  19. NMR analysis of a fluorocarbon copolymer

    SciTech Connect

    Smith, R.E.; Smith, C.H.

    1987-10-01

    Vinylidene fluoride (VF/sub 2/) can be copolymerized with chlorotrifluoroethylene (CTFE) in an aqueous emulsion using a peroxide chain initiator. The physical properties of the resulting fluorocarbon polymer depend on the ratio of VF/sub 2/ to CTFE and the randomness of the copolymerization. When CTFE and VF are polymerized in an approximately 3:1 mole ratio, the resulting polymer is soluble in acetone (and other solvents) at room temperature. Using proton and fluorine-19 NMR, the mole ratio of CTFE to VF/sub 2/, the emulsifier (perfluorodecanoate) concentration, and the randomness of copolymerization can be determined. A trifluorotoluene internal standard is added to a d/sub 6/-acetone solution of the fluoropolymer. Proton NMR is used to determine the amount of VF/sub 2/. Fluorine-19 NMR is used to measure the amount of emulsifier and the randomness of copolymerization. Each analysis requires about 5 minutes, and is quite precise, with relative standard deviations from 3 to 10% (10 replicates analyzed). In addition, the results from NMR analyses agree well with wet chemical analyses. 4 refs., 3 figs., 3 tabs.

  20. Effect of fluorocarbons on acetylcholinesterase activity and some counter measures

    NASA Technical Reports Server (NTRS)

    Young, W.; Parker, J. A.

    1975-01-01

    An isolated vagal sympathetic heart system has been successfully used for the study of the effect of fluorocarbons (FCs) on cardiac performance and in situ enzyme activity. Dichlorodifluoromethane sensitizes this preparation to sympathetic stimulation and to exogenous epinephrine challenge. Partial and complete A-V block and even cardiac arrest have been induced by epinephrine challenge in the FC sensitized heart. Potassium chloride alone restores the rhythmicity but not the normal contractility of the heart in such a situation. Addition of glucose will, however, completely restore the normal function of the heart which is sensitized by dichlorodifluoromethane. The ED 50 values of acetylcholinesterase activity which are used as a measure of relative effectiveness of fluorocarbons are compared with the maximum permissible concentration. Kinetic studies indicate that all the fluorocarbons tested so far are noncompetitive.

  1. Cause and Effects of Fluorocarbon Degradation in Electronics and Opto-Electronic Systems

    NASA Technical Reports Server (NTRS)

    Predmore, Roamer E.; Canham, John S.

    2002-01-01

    Trace degradation of fluorocarbon or halocarbon materials must be addressed in their application in sensitive systems. As the dimensions and/or tolerances of components in a system decrease, the sensitivity of the system to trace fluorocarbon or halocarbon degradation products increases. Trace quantities of highly reactive degradation products from fluorocarbons have caused a number of failures of flight hardware. It is of utmost importance that the risk of system failure, resulting from trace amounts of reactive fluorocarbon degradation products be addressed in designs containing fluorocarbon or halocarbon materials. Thermal, electrical, and mechanical energy input into the system can multiply the risk of failure.

  2. Method and means for producing fluorocarbon finishes on fibrous structures

    NASA Technical Reports Server (NTRS)

    Toy, Madeline S. (Inventor); Stringham, Roger S. (Inventor); Fogg, Lawrence C. (Inventor)

    1981-01-01

    An improved process and apparatus is provided for imparting chemically bonded fluorocarbon finishes to textiles. In the process, the textiles are contacted with a gaseous mixture of fluoroolefins in an inert diluent gas in the presence of ultraviolet light under predetermined conditions.

  3. Gain and loss mechanisms in fluorocarbon plasmas

    NASA Astrophysics Data System (ADS)

    Nelson, Caleb Timothy

    Understanding dominant reaction channels for important gas-phase species in fluorocarbon plasmas is crucial to the ability to control surface evolution and morphology. In order to accomplish this goal a modified GEC reference ICP reactor is used in tandem with Fourier transform infrared spectroscopy (FTIR) to measure the densities of stable species. Integrated absorption cross-sections are presented for all fundamental bands in the 650 cm-1 to 2000 cm-1 region for C3F6, C4F 8, C3F8, C2F6, C2F 4, and CF4. The results show that although the absorption profile changes significantly, the integrated absorption cross-sections, with the exception of CF4, do not change significantly as gas temperature increases from 25°C to 200°C. However, the internal temperature of the absorbing species can be estimated from the rotational band maximum in most cases. Species densities obtained with the aforementioned cross-sections are used with a novel analysis technique to quantify gain and loss rates as functions of residence time, pressure, and deposited power. CF4, C2F6, C3F8, and C4F 10, share related production channels, which increase in magnitude as the plasma pressure, deposited power, or surface temperature are raised. CF 2 is primarily produced through a combination of surface production (the magnitude also increases with temperature) and electron impact dissociation of C2F4, while it is predominantly lost in the large reactor to gas-phase addition to form C2F4. Time-resolved FTIR results are used to measure a cross-section of 1.8x10-14 cm3/s for the reaction between CF2 radicals creating C2F4. Finally, C2F4 originates through the electron impact dissociation of c- C4F8. The loss process for C2F4 is undetermined, but the results indicate that it could occur on reactor surfaces. Neither the density of fluorine nor the ion flux to the chuck surface changes substantially with wall temperature. We show that increases in the deposition rate in a heated chamber are due to an increase in the fluxes of depositing neutral species. Furthermore, the sticking coefficient for these species does not change significantly as a function of surface temperature. Instead, surface temperature elevates the yield of etchant species, which terminate broken bonds to increase the desorption rates of stable species.

  4. [Formation of biologically active substances during cholesterol oxidation on the surface of fluorocarbon emulsions].

    PubMed

    Berezov, A T; Ivanov, A S; Ivkov, V G; Obraztsov, V V; Khalilov, E M; Archakov, A I

    1990-09-01

    Oxidative modification of cholesterol on the surface of fluorocarbon emulsions was studied. The oxidation yielded one primary product--7-peroxycholesterol. It was shown that the obtained cholesterol C7 derivatives possess a high biological activity. It was concluded that the possibility of oxidative modification of plasma substances on the surface of fluorocarbon emulsion particles with the formation of highly active compounds must be taken into account when using the fluorocarbon particles in medicine. PMID:2268717

  5. Spraylon fluorocarbon encapsulation for silicon solar cell arrays

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A development program was performed for evaluating, modifying, and optimizing the Lockheed formulated liquid transparent filmforming Spraylon fluorocarbon protective coating for silicon solar cells and modules. The program objectives were designed to meet the requirements of the low-cost automated solar cell array fabrication process. As part of the study, a computer program was used to establish the limits of the safe working stress in the coated silicon solar cell array system under severe thermal shock.

  6. Reaction of uranium and the fluorocarbon FC-75

    NASA Astrophysics Data System (ADS)

    Young, R. H.

    1985-04-01

    Because of criticality concerns with water cooling in enriched uranium upgrading, a fluorocarbon has been evaluated as a replacement coolant for internal module components in the Plasma Separation Process (PSP). The interaction of bulk uranium and of powdered uranium with FC-75 has been investigated at temperatures between 200 and 700 C. The gas pressure and the metal temperature were monitored as a function of time. Modest temperature changes of 50 to 100 C were observed for the bulk uranium/fluorocarbon reaction. Much larger changes (up to 1000 C) were noted for the reaction involving high surface area uranium powder. These temperature transients, particularly for the powdered uranium reaction, were short-lived ( 10 seconds) and indicative of the formation of a protective layer of reaction products. Analysis of residual gas products by infrared spectroscopy indicated that one potentially serious hazard, UF6, was not present; however, several small toxic fluorocarbons were produced by thermolysis and/or reaction. X-ray diffraction analysis of the residual solids indicated UF4 and UO2 were the major solid products.

  7. Spraylon fluorocarbon encapsulation for silicon solar cell arrays, phase 3

    NASA Technical Reports Server (NTRS)

    Naes, L. G.

    1978-01-01

    The liquid transparent film-forming, fluorocarbon, Spraylon, a protective coating for terrestrial solar cell modules was evaluated. Two modules were completed and field tested. Problems developed early in the field testing which led to the shortened test period, specifically, lifting of the antireflection coating, followed in some areas by complete film delamination. It is believed that although these problems were certainly induced by the presence of the SPRAYLON film, they were not failures of the material per se. Instead, assembly procedures, module design, and cell coating quality should be evaluated to determine cause of failure.

  8. Discovery during Hydrogen Annealing: Formation of Nanoscale Fluorocarbon Tubular Structures

    NASA Astrophysics Data System (ADS)

    Hao, Xiuchun; Tanaka, Sinya; Masuda, Atsuhiko; Maenaka, Kazusuke; Higuchi, Kohei

    2013-09-01

    A novel fabrication method for nanoscale tubular structures is presented in this paper. The tubular structures can be obtained by heating single-crystal silicon trenches or pillars formed by the inductively coupled plasma reactive-ion etching (ICP-RIE) Bosch process in hydrogen ambient. The importance of initial vacuum in the reaction chamber for tube formation and the tube formation mechanism were discussed. The components and sidewall size of the tubular structure were also studied to verify that the tube is made of the fluorocarbon (CF) passivation layer deposited by the Bosch process. The CF tubular structure would be a promising structure for BioMEMS.

  9. Micellization behavior of aromatic moiety bearing hybrid fluorocarbon sulfonate surfactants.

    PubMed

    Wadekar, Mohan N; Boekhoven, Job; Jager, Wolter F; Koper, Ger J M; Picken, Stephen J

    2012-02-21

    Aggregation behavior and thermodynamic properties of two novel homologous aromatic moiety bearing hybrid fluorocarbon surfactants, sodium 2-(2-(4-ethylphenyl)-1,1,2,2-tetrafluoroethoxy)-1,1,2,2-tetrafluoroethanesulfonate (1) and sodium 2-(1,1,2,2-tetrafluoro-2-(4-vinylphenyl)ethoxy)-1,1,2,2-tetrafluoroethanesulfonate (2) were studied using surface tension measurements and isothermal titration calorimetry (ITC) in dilute aqueous solutions at room temperature. Because of the aromatic group in the hydrophobic tail, both surfactants are soluble at room temperature unlike their starting precursor, 5-iodooctafluoro-3-oxapentanesulfonate as well as several other fluorocarbon sulfonic acid salts. Moreover, the surfactant 2 has the ability that it can be polymerized once microemulsions are formed with it. The ionic conductivity measurements of 1 at five different temperatures from 288 to 313 K were carried out to study the effect of temperature on the micellization and its thermodynamics. The pseudophase separation model was applied to estimate thermodynamic quantities from conductivity data. The Gibbs energy of micellization versus temperature exhibited the characteristic U-shaped behavior with a minimum at 306 K. The micellization process was found to be largely entropy driven. Because of its hybrid structure, the entropy change of micellization for 1 was larger than what is common for hydrocarbon surfactants like SDS but less than for fully fluorinated surfactants like NaPFO. The micellization process was found to be following the entropy-enthalpy compensation phenomena. PMID:22263549

  10. Enhanced removal of radioactive particles by fluorocarbon surfactant solutions

    SciTech Connect

    Kaiser, R.; Harling, O.K.

    1993-08-01

    The proposed research addressed the application of ESI`s particle removal process to the non-destructive decontamination of nuclear equipment. The cleaning medium used in this process is a solution of a high molecular weight fluorocarbon surfactant in an inert perfluorinated liquid which results in enhanced particle removal. The perfluorinated liquids of interest, which are recycled in the process, are nontoxic, nonflammable, and environmentally compatible, and do not present a hazard to the ozone layer. The information obtained in the Phase 1 program indicated that the proposed ESI process is technically effective and economically attractive. The fluorocarbon surfactant solutions used as working media in the ESI process survived exposure of up to 10 Mrad doses of gamma rays, and are considered sufficiently radiation resistant for the proposed process. Ultrasonic cleaning in perfluorinated surfactant solutions was found to be an effective method of removing radioactive iron (Fe 59) oxide particles from contaminated test pieces. Radioactive particles suspended in the process liquids could be quantitatively removed by filtration through a 0.1 um membrane filter. Projected economics indicate a pre-tax pay back time of 1 month for a commercial scale system.

  11. Fluorocarbon 113 exposure and cardiac dysrhythmias among aerospace workers.

    PubMed

    Egeland, G M; Bloom, T F; Schnorr, T M; Hornung, R W; Suruda, A J; Wille, K K

    1992-01-01

    We investigated the cardiotoxic effects of 1,1,2-Trichloro-1,2,2- Trifluoroethane (fluorocarbon 113 or FC113) exposures among healthy workers cleaning rocket and ground support equipment for the National Aeronautic and Space Administration (NASA) programs. Exposure and ambulatory electrocardiographic (ECG) monitoring data were evaluated on 16 workers, each of whom was examined on exposed and nonexposed workdays. We examined whether there was a greater rate of dysrhythmias on an exposed workday relative to a nonexposed workday. Overall, we found no within subject differences in the rate of ventricular and supraventricular premature beats (number per 1,000 heart beats), fluctuations in the length of the P-R interval, or heart rate. We found that levels of FC113 exposures below the Occupational Safety and Health Administration (OSHA) 8-hour time-weighted-average (TWA) standard of 1,000 ppm did not induce cardiac dysrhythmias or subtle changes in cardiac activity. However, because fluorocarbons may sensitize the heart to epinephrine, this study's negative findings based on sedentary and fairly healthy workers may not be generalizable to other populations of workers who are not as healthy or engaged in more physically demanding work. PMID:1463030

  12. Cholesterol oxidation on fluorocarbon emulsion surface leads to the formation of 7-peroxycholesterol.

    PubMed

    Beriozov, A T; Ivanov, A S; Ivkov, V G; Obraztsov, V V; Khalilov, E M; Archakov, A I

    1990-06-18

    Formation of biologically active oxidized derivatives of cholesterol as a result of its oxidation on the surface of fluorocarbon emulsions was studied. A single product of cholesterol oxidation, 7-peroxycholesterol, was found. It was shown that 7-peroxycholesterol and its derivative 7-keto-cholesterol inhibit the rosette formation between human T-lymphocytes and sheep erythrocytes. These substances exert a strong cytostatic action on the growth of procaryotic and eucaryotic cell cultures. Thus, oxidative modification of blood plasma components on the surface of fluorocarbon emulsion particles with the formation of highly active compounds must be taken into account when using the fluorocarbon emulsions in medicine. PMID:2365071

  13. Application of cyclic fluorocarbon/argon discharges to device patterning

    SciTech Connect

    Metzler, Dominik; Uppiredi, Kishore; Bruce, Robert L.; Miyazoe, Hiroyuki; Zhu, Yu; Price, William; Sikorski, Ed S.; Li, Chen; Engelmann, Sebastian U.; Joseph, Eric A.; Oehrlein, Gottlieb S.

    2015-11-13

    With increasing demands on device patterning to achieve smaller critical dimensions and pitches for the 5nm node and beyond, the need for atomic layer etching (ALE) is steadily increasing. In this study, a cyclic fluorocarbon/Ar plasma is successfully used for ALE patterning in a manufacturing scale reactor. Self-limited etching of silicon oxide is observed. The impact of various process parameters on the etch performance is established. The substrate temperature has been shown to play an especially significant role, with lower temperatures leading to higher selectivity and lower etch rates, but worse pattern fidelity. The cyclic ALE approach established with this work is shown to have great potential for small scale device patterning, showing self-limited etching, improved uniformity and resist mask performance.

  14. Application of cyclic fluorocarbon/argon discharges to device patterning

    DOE PAGESBeta

    Metzler, Dominik; Uppiredi, Kishore; Bruce, Robert L.; Miyazoe, Hiroyuki; Zhu, Yu; Price, William; Sikorski, Ed S.; Li, Chen; Engelmann, Sebastian U.; Joseph, Eric A.; et al

    2015-11-13

    With increasing demands on device patterning to achieve smaller critical dimensions and pitches for the 5nm node and beyond, the need for atomic layer etching (ALE) is steadily increasing. In this study, a cyclic fluorocarbon/Ar plasma is successfully used for ALE patterning in a manufacturing scale reactor. Self-limited etching of silicon oxide is observed. The impact of various process parameters on the etch performance is established. The substrate temperature has been shown to play an especially significant role, with lower temperatures leading to higher selectivity and lower etch rates, but worse pattern fidelity. The cyclic ALE approach established with thismore » work is shown to have great potential for small scale device patterning, showing self-limited etching, improved uniformity and resist mask performance.« less

  15. Anode/organic interface modification by plasma polymerized fluorocarbon films

    NASA Astrophysics Data System (ADS)

    Tang, J. X.; Li, Y. Q.; Zheng, L. R.; Hung, L. S.

    2004-04-01

    We investigated the effects of plasma polymerized fluorocarbon films (CFx) on device performance in organic light-emitting diodes (OLEDs). OLEDs with a 0.3-nm thick CFx film on an untreated indium tin oxide (ITO) anode showed identical current density-voltage characteristics and improved operational stability, as compared to the device with an ultra violet-treated ITO anode. Hole injection was virtually blocked when Au was replaced for ITO as an anode, while an ultrathin CFx film overlaid on an Au anode substantially reduced the barrier height and facilitated hole injection. The enhancement of hole injection was attributed to the manipulation of the energy level offset at the anode/organic interface by the formation of an artificial dipolar layer resulting from rich, negatively charged fluorine. The dipolar interface was fairly stable when being exposed to air, and the improved operational stability of OLEDs was ascribed to the stability of the ITO/CFx anode against atmospheric moisture.

  16. Marine biofouling on the fluorocarbon coatings comprising PTFE powders

    NASA Astrophysics Data System (ADS)

    Zhang, Zhan-ping; Qi, Yu-hong; Liu, Hong; Zhang, Zheng

    2009-07-01

    Fluorocarbon coatings were developed with respectively 10%, 20% and 30% PTFE powder to prevent marine biofouling. Influence of content of PTFE on microstructures and roughness of coatings was investigated using SEM and roughometer. It was studied that the effects of coating roughness on settlement of benthic diatom and Ectocarpus by using biological microscope, stereo microscope, image processing and spectrophotometer. Results indicated that the surface roughness of coatings decreases and the quantity of benthic diatom and Ectocarpus reduces attaching onto the coating with the increase of content of PTFE in paint studied. Benthic diatoms attached much more on horizontal specimen than on vertical one; they prefer to settle onto the coatings that there are lots of micro-cracks in it. These results are helpful for developing new non-toxic antifouling paints.

  17. Selective Plasma Deposition of Fluorocarbon Films on SAMs

    NASA Technical Reports Server (NTRS)

    Crain, Mark M., III; Walsh, Kevin M.; Cohn, Robert W.

    2006-01-01

    A dry plasma process has been demonstrated to be useful for the selective modification of self-assembled monolayers (SAMs) of alkanethiolates. These SAMs are used, during the fabrication of semiconductor electronic devices, as etch masks on gold layers that are destined to be patterned and incorporated into the devices. The selective modification involves the formation of fluorocarbon films that render the SAMs more effective in protecting the masked areas of the gold against etching by a potassium iodide (KI) solution. This modification can be utilized, not only in the fabrication of single electronic devices but also in the fabrication of integrated circuits, microelectromechanical systems, and circuit boards. In the steps that precede the dry plasma process, a silicon mold in the desired pattern is fabricated by standard photolithographic techniques. A stamp is then made by casting polydimethylsiloxane (commonly known as silicone rubber) in the mold. The stamp is coated with an alkanethiol solution, then the stamp is pressed on the gold layer of a device to be fabricated in order to deposit the alkanethiol to form an alkanethiolate SAM in the desired pattern (see figure). Next, the workpiece is exposed to a radio-frequency plasma generated from a mixture of CF4 and H2 gases. After this plasma treatment, the SAM is found to be modified, while the exposed areas of gold remain unchanged. This dry plasma process offers the potential for forming masks superior to those formed in a prior wet etching process. Among the advantages over the wet etching process are greater selectivity, fewer pin holes in the masks, and less nonuniformity of the masks. The fluorocarbon films formed in this way may also be useful as intermediate layers for subsequent fabrication steps and as dielectric layers to be incorporated into finished products.

  18. Tunable hydrophilicity on a hydrophobic fluorocarbon polymer coating on silicon

    SciTech Connect

    Kolari, K.; Hokkanen, A.

    2006-07-15

    An efficient, economic, reliable, and repeatable patterning procedure of hydrophobic surfaces was developed. A fluorocarbon polymer derived from the C{sub 4}F{sub 8} gas in an inductively coupled plasma etcher was used as the hydrophobic coating. For a subsequent patterning of hydrophilic apertures on the polymer, a short O{sub 2} plasma exposure through a silicon shadow mask was utilized. The overall hydrophilicity of the patterned surface can be tuned by the duration of the O{sub 2} plasma exposure, and also by the density and the size of the hydrophilic apertures. The laborious photolithography and tricky lift-off procedures are avoided. Optimization of the whole patterning process is explained thoroughly and supported with experimental data. The hydrophilic adhesion of the patterned polymer was evaluated with aqueous droplets, which were studied on matrices of the hydrophilic apertures of different sizes. The deposition parameters of the fluorocarbon polymer, the size of the droplet required to enable rolling on the patterned surface, and the duration of the O{sub 2} plasma exposure were considered as the main parameters. To determine the achievable resolution of the patterning procedure, the subsurface etching beneath the shadow mask was evaluated. The results show that a resolution of less than 10 {mu}m can be achieved. The simple hydrophilic patterning procedure described here can be used for the production of on-plane microfluidics, where a controlled adhesion or decohesion of 8-50 {mu}l droplets on the surface with a variable hydrophilicity from one location to another can be achieved.

  19. Fluorocarbon Surfactant Polymers: Effect of Perfluorocarbon Branch Density on Surface Active Properties

    PubMed Central

    Wang, Shuwu; Marchant, Roger E.

    2005-01-01

    We describe a series of fluorocarbon surfactant polymers designed for modifying fluorocarbon surfaces such as poly(tetrafluoroethylene). Novel fluorocarbon surfactant polymers poly(N-vinyldextranaldonamide-co-N-vinylperfluoroundecanamide), in which hydrophilic dextran oligosaccharides and hydrophobic perfluoroundecanoyl groups were incorporated sequentially onto a poly(vinylamine) backbone, were synthesized and characterized by FT-IR, NMR, and XPS spectroscopy. By adjusting the feed ratio of dextran to fluorocarbon branches, surfactant polymers with different hydrophilic/hydrophobic balances were prepared. The surface activity of the surfactants at the air/water interface was demonstrated by significant reductions in water surface tension. Surfactant adsorption and adhesion at the solid PTFE/aqueous interface were examined under well-defined dynamic flow conditions, using a rotating disk system. The surface activity at the air/water interface and adhesion stability on PTFE under an applied shear stress both increase with increasing density of fluorocarbon branches on the polymer backbone. The results show that stable surfactant adhesion on PTFE can be achieved by adjusting the hydrophilic dextran to hydrophobic fluorocarbon branch ratio. PMID:16429594

  20. Investigations of the environmental acceptability of fluorocarbon alternatives to chlorofluorocarbons.

    PubMed Central

    McFarland, M

    1992-01-01

    Chlorofluorocarbons (CFCs) are currently used in systems for preservation of perishable foods and medical supplies, increasing worker productivity and consumer comfort, conserving energy and increasing product reliability. As use of CFCs is phased out due to concerns of ozone depletion, a variety of new chemicals and technologies will be needed to serve these needs. In choosing alternatives, industry must balance concerns over safety and environmental acceptability and still meet the preformance characteristics of the current technology, the only viable alternatives meeting the safety, performance, and environmental requirements for the remaining 40% of demand are fluorocarbons, hydrochlorofluorocarbons (HCFs), and hydrofluorocarbons (HFCs). HCFCs and HFCs possess many of the desirable properties of the CFCs, but because of the, hydrogen, they results in shorter atmospheric lifetimes compared to CFCs and reduces their potential to contribute to stratospheric ozone depletion or global warming; HFCs do not contain chlorine and have no potential to destroy ozone. This paper provides an overview of challenges faced by industry, regulators, and society in general in continuing to meet societal needs and consumer demands while reducing risk to the enviroment without compromising consumer or worker safety. PMID:11607257

  1. Investigations of the environmental acceptability of fluorocarbon alternatives to chlorofluorocarbons.

    PubMed

    McFarland, M

    1992-02-01

    Chlorofluorocarbons (CFCs) are currently used in systems for preservation of perishable foods and medical supplies, increasing worker productivity and consumer comfort, conserving energy and increasing product reliability. As use of CFCs is phased out due to concerns of ozone depletion, a variety of new chemicals and technologies will be needed to serve these needs. In choosing alternatives, industry must balance concerns over safety and environmental acceptability and still meet the preformance characteristics of the current technology, the only viable alternatives meeting the safety, performance, and environmental requirements for the remaining 40% of demand are fluorocarbons, hydrochlorofluorocarbons (HCFs), and hydrofluorocarbons (HFCs). HCFCs and HFCs possess many of the desirable properties of the CFCs, but because of the, hydrogen, they results in shorter atmospheric lifetimes compared to CFCs and reduces their potential to contribute to stratospheric ozone depletion or global warming; HFCs do not contain chlorine and have no potential to destroy ozone. This paper provides an overview of challenges faced by industry, regulators, and society in general in continuing to meet societal needs and consumer demands while reducing risk to the enviroment without compromising consumer or worker safety. PMID:11607257

  2. Roughening of porous SiCOH materials in fluorocarbon plasmas

    NASA Astrophysics Data System (ADS)

    Bailly, F.; David, T.; Chevolleau, T.; Darnon, M.; Posseme, N.; Bouyssou, R.; Ducote, J.; Joubert, O.; Cardinaud, C.

    2010-07-01

    Porous SiCOH materials integration for integrated circuits faces serious challenges such as roughening during the etch process. In this study, atomic force microscopy is used to investigate the kinetics of SiCOH materials roughening when they are etched in fluorocarbon plasmas. We show that the root mean square roughness and the correlation length linearly increase with the etched depth, after an initiation period. We propose that: (1) during the first few seconds of the etch process, the surface of porous SiCOH materials gets denser. (2) Cracks are formed, leading to the formation of deep and narrow pits. (3) Plasma radicals diffuse through those pits and the pore network and modify the porous material at the bottom of the pits. (4) The difference in material density and composition between the surface and the bottom of the pits leads to a difference in etch rate and an amplification of the roughness. In addition to this intrinsic roughening mechanism, the presence of a metallic mask (titanium nitride) can lead to an extrinsic roughening mechanism, such as micromasking caused by metallic particles originating form the titanium nitride mask.

  3. Electron attachment and positive ion chemistry of monohydrogenated fluorocarbon radicals

    NASA Astrophysics Data System (ADS)

    Wiens, Justin P.; Shuman, Nicholas S.; Miller, Thomas M.; Viggiano, Albert A.

    2015-08-01

    Rate coefficients and product branching fractions for electron attachment and for reaction with Ar+ are measured over the temperature range 300-585 K for three monohydrogenated fluorocarbon (HFC) radicals (CF3CHF, CHF2CF2, and CF3CHFCF2), as well as their five closed-shell precursors (1-HC2F4I, 2-HC2F4I, 2-HC2F4Br, 1-HC3F6I, 2-HC3F6Br). Attachment to the HFC radicals is always fairly inefficient (between 0.1% and 10% of the Vogt-Wannier capture rate), but generally faster than attachment to analogous perfluorinated carbon radicals. The primary products in all cases are HF-loss to yield CnFm-1- anions, with only a minor branching to F- product. In all cases the temperature dependences are weak. Attachment to the precursor halocarbons is near the capture rate with a slight negative temperature dependence in all cases except for 2-HC2F4Br, which is ˜10% efficient at 300 K and becomes more efficient, approaching the capture rate at higher temperatures. All attachment kinetics are successfully reproduced using a kinetic modeling approach. Reaction of the HFC radicals with Ar+ proceeds at or near the calculated collisional rate coefficient in all cases, yielding a wide variety of product ions.

  4. Temperature dependence of acoustic impedance for specific fluorocarbon liquids

    NASA Astrophysics Data System (ADS)

    Marsh, Jon N.; Hall, Christopher S.; Wickline, Samuel A.; Lanza, Gregory M.

    2002-12-01

    Recent studies by our group have demonstrated the efficacy of perfluorocarbon liquid nanoparticles for enhancing the reflectivity of tissuelike surfaces to which they are bound. The magnitude of this enhancement depends in large part on the difference in impedances of the perfluorocarbon, the bound substrate, and the propagating medium. The impedance varies directly with temperature because both the speed of sound and the mass density of perfluorocarbon liquids are highly temperature dependent. However, there are relatively little data in the literature pertaining to the temperature dependence of the acoustic impedance of these compounds. In this study, the speed of sound and density of seven different fluorocarbon liquids were measured at specific temperatures between 20 C and 45 C. All of the samples demonstrated negative, linear dependencies on temperature for both speed of sound and density and, consequently, for the acoustic impedance. The slope of sound speed was greatest for perfluorohexane (-278+/-1.5 cm/s-C) and lowest for perfluorodichlorooctane (-222+/-0.9 cm/s-C). Of the compounds measured, perfluorohexane exhibited the lowest acoustic impedance at all temperatures, and perfluorodecalin the highest at all temperatures. Computations from a simple transmission-line model used to predict reflectivity enhancement from surface-bound nanoparticles are discussed in light of these results.

  5. Final report of ''Fundamental Surface Reaction Mechanisms in Fluorocarbon Plasma-Based Processing''

    SciTech Connect

    Gottlieb S. Oehrlein; H. Anderson; J. Cecchi; D. Graves

    2004-09-21

    This report provides a summary of results obtained in research supported by contract ''Fundamental Surface Reaction Mechanisms in Fluorocarbon Plasma-Based Processing'' (Contract No. DE-FG0200ER54608). In this program we advanced significantly the scientific knowledge base on low pressure fluorocarbon plasmas used for patterning of dielectric films and for producing fluorocarbon coatings on substrates. We characterized important neutral and ionic gas phase species that are incident at the substrate, and the processes that occur at relevant surfaces in contact with the plasma. The work was performed through collaboration of research groups at three universities where significantly different, complementary tools for plasma and surface characterization, computer simulation of plasma and surface processes exist. Exchange of diagnostic tools and experimental verification of key results at collaborating institutions, both experimentally and by computer simulations, was an important component of the approach taken in this work.

  6. Synthesis and tuning of bimodal mesoporous silica by combined hydrocarbon/fluorocarbon surfactant templating.

    PubMed

    Xing, Rong; Lehmler, Hans-Joachim; Knutson, Barbara L; Rankin, Stephen E

    2009-06-01

    Hydrocarbon and fluorocarbon surfactants show highly nonideal mixing that under some conditions results in demixing of the two types of surfactants into distinct populations of fluorocarbon-rich and hydrocarbon-rich aggregates. This also occurs in materials prepared by cooperative assembly of hydrolyzed tetraethoxysilane with mixtures of cetyltrimethylammonium chloride (CTAC) and 1,1,2,2-tetrahydro-perfluorodecylpyridinium chloride (HFDePC). Here, we report conditions under which demixed micelles lead to bimodal mesoporous materials (including specific concentrations of ammonia and salt in the synthesis solution) and show that the sizes of the hydrocarbon-templated and fluorocarbon-templated pores can be finely and independently controlled by adding lipophilic or fluorophilic oils, respectively. Nitrogen sorption isotherms and transmission electron microscopy provide clear evidence for a single phase of demixed but disordered wormhole-like pores. PMID:19323503

  7. Nanostructures in water-in-CO2 microemulsions stabilized by double-chain fluorocarbon solubilizers.

    PubMed

    Sagisaka, Masanobu; Iwama, Shuho; Ono, Shinji; Yoshizawa, Atsushi; Mohamed, Azmi; Cummings, Stephen; Yan, Ci; James, Craig; Rogers, Sarah E; Heenan, Richard K; Eastoe, Julian

    2013-06-25

    High-pressure small-angle neutron scattering (HP-SANS) studies were conducted to investigate nanostructures and interfacial properties of water-in-supercritical CO2 (W/CO2) microemulsions with double-fluorocarbon-tail anionic surfactants, having different fluorocarbon chain lengths and linking groups (glutarate or succinate). At constant pressure and temperature, the microemulsion aqueous cores were found to swell with an increase in water-to-surfactant ratio, W0, until their solubilizing capacities were reached. Surfactants with fluorocarbon chain lengths of n = 4, 6, and 8 formed spherical reversed micelles in supercritical CO2 even at W0 over the solubilizing powers as determined by phase behavior studies, suggesting formation of Winsor-IV W/CO2 microemulsions and then Winsor-II W/CO2 microemulsions. On the other hand, a short C2 chain fluorocarbon surfactant analogue displayed a transition from Winsor-IV microemulsions to lamellar liquid crystals at W0 = 25. Critical packing parameters and aggregation numbers were calculated by using area per headgroup, shell thickness, the core/shell radii determined from SANS data analysis: these parameters were used to help understand differences in aggregation behavior and solubilizing power in CO2. Increasing the microemulsion water loading led the critical packing parameter to decrease to ~1.3 and the aggregation number to increase to >90. Although these parameters were comparable between glutarate and succinate surfactants with the same fluorocarbon chain, decreasing the fluorocarbon chain length n reduced the critical packing parameter. At the same time, reducing chain length to 2 reduced negative interfacial curvature, favoring planar structures, as demonstrated by generation of lamellar liquid crystal phases. PMID:23701401

  8. A molecular dynamics investigation of fluorocarbon based layer-by-layer etching of silicon and SiO2

    NASA Astrophysics Data System (ADS)

    Rauf, S.; Sparks, T.; Ventzek, P. L. G.; Smirnov, V. V.; Stengach, A. V.; Gaynullin, K. G.; Pavlovsky, V. A.

    2007-02-01

    A molecular dynamics model is used to understand the layer-by-layer etching of Si and SiO2 using fluorocarbon and Ar+ ions. In these two-step etch processes, a nanometer-scale fluorocarbon passivation layer is grown on the material's surface using low energy CFx+ ions or radicals. The top layers of the material are then reactive ion etched by Ar+ ions utilizing the fluorocarbon already present on the material surface. By repeating these two steps, Si or SiO2 can be etched with nanometer-scale precision and the etch rate is considerably faster than what traditional atomic layer etching techniques provide. The modeling results show that fluorocarbon passivation films can be grown in a self-limiting manner on both Si and SiO2 using low energy CF2+ and CF3+ ions. The fluorocarbon passivation layer is a few angstroms thick, and its thickness increases with the fluorocarbon ion's energy. Increasing the ion energy, however, amorphizes the top atomic layers of the material. In addition, the fluorocarbon film becomes F rich with increasing ion energy. Simulations of fluorocarbon passivated SiO2 surface show that Ar+ ions with energy below 50eV etch Si (within SiO2) in a self-limiting manner. Si etching stops once F in the fluorocarbon passivation layer is exhausted or is pushed too deep into the substrate. Oxygen within SiO2 is more easily sputtered from the material surface than Si, and the top layers of SiO2 are expected to become O deficient during Ar+ ion bombardment. Ar+ ion etching of fluorocarbon passivated Si also appears to be self-limiting below 30eV ion energy, and etching stops once F on the material surface is either consumed or becomes inaccessible.

  9. A fluorocarbon plastic scintillator for neutron detection: Proof of concept

    NASA Astrophysics Data System (ADS)

    Hamel, Matthieu; Sibczynski, Pawel; Blanc, Pauline; Iwanowska, Joanna; Carrel, Frdrick; Syntfeld-Ka?uch, Agnieszka; Normand, Stphane

    2014-12-01

    The fast neutron nuclear reactions, such as 19F(n, ?)16N and 19F(n, p)19O, can be used to detect highly energetic neutrons due to their energy thresholds above which these activation reactions can occur. This was recently shown (Gozani et al., 2011 [2]) as a means to detect concealed nuclear materials via the detection of the high energy (?3 MeV) prompt neutrons emitted during the photofission process. Fluorine-loaded scintillation detectors, such as inorganic BaF2 and CaF2, and non-hydrogenous fluorocarbon (FC) liquid scintillators, such as Saint-Gobain BC-509 and Eljen Technology EJ-313, are possible candidates. The latter was selected and implemented in the above mentioned reference. In our paper, we propose a new pentafluorostyrene-based plastic scintillator (F-plastic) which can be a good alternative to the abovementioned scintillators. The fluorine content of F-plastic is equal to 3.731022 atoms/cm3, and the F/H ratio is 1.66. The fluorescence and radioluminescence spectra of the F-plastic display an emission maximum centered approximately at 420 nm. The light output measured for gamma rays is 3100300 photons/MeV, which is approximately 30% of the light output of the standard EJ-200 plastic scintillator and is similar to EJ-313. The response of the F-plastic to neutrons and gamma rays is presented and compared to the EJ-200 scintillator. Additionally, the n/? pulse shape discrimination (PSD) was measured and showed improvement of the discrimination at neutron energies as high as 3 MeV.

  10. The environmental history and probable future of Fluorocarbon 11

    SciTech Connect

    Khalil, M.A.K.; Rasmussen, R.A.

    1993-12-01

    The atmospheric concentration of fluorocarbon 11 (F-11) has increased steadily since it was first put into commercial use in the late 1930s and early 1940s. The observed trends, however, have two periods of dramatic declines. The atmospheric trends reflect estimated emissions, which reached highest values in 1974 (340-355 Gg/yr; 1 Gg = 10(exp 9)g) and again in 1988 (314-380 Gg/yr). The observed concentrations and trends agree extremely well with those calculated from independent estimates of emissions from the various sources. Atmospheric concentrations of F-11 are calculated from a mass balance theory involving seven reservoirs and their interactions. Three of the reservoirs are at the Earth`s surface arising from the uses of F-11 (quick-release applications such as open cell foams and aerosols, nonhermetically sealed refrigeration, and rigid polyurethane foams). We estimate that of the 9150 Gg of F-11 that have been produced throughout its history, at present about 1040 Gg are tied up in rigid foams (90 Gg and 24 Gg are tied up refrigeration and quick-release applications, respectively). There are four environmental reservoirs (deep oceans, the ocean mixed layer, the troposphere, and the stratosphere). F-11 is dynamically exchanged between these reservoirs and is destroyed principally by photolysis in the stratosphere and by soils at the Earth`s surface. The future concentrations of F-11 depend on leakage rates from the surface reservoirs and the atmospheric lifetime. It seems that concentrations are not likely to reach the peaks expected earlier and are likely to decline faster than previously thought. This abstract, the figures, and their captions form a self-contained condensed description of our results.

  11. Press Coverage of the Fluorocarbon Controversy: The Rise and Decline of a "Hot" Scientific Issue.

    ERIC Educational Resources Information Center

    Mahaffy, Cheryl

    This paper reviews press coverage of events surrounding the 1977 governmental decision to ban fluorocarbons in spray cans in the United States. The research reported focused on the years 1972 to 1978 and involved a count of the number of items published in selected newspapers and magazines or aired on the three major networks' evening news

  12. Plasma-deposited fluorocarbon coatings for passive and active integrated optical devices

    NASA Astrophysics Data System (ADS)

    Wirges, Werner; Bauer-Gogonea, Simona; Bauer, Stefan; Gerhard-Multhaupt, Reimund; Martinu, Ludvik; Klemberg-Sapieha, Jolanta E.; Wertheimer, Michael R.

    1994-07-01

    Amorphous fluorocarbon polymers are attractive materials for optical applications because of their high transparency at wavelengths up to 3 micrometers because of the absence of C-H bonds. since 1989 DuPont's amorphous fluoropolymer Teflon AF is available, films of which can be fabricated by means of spin, spray, or dip coating from solution or by use of compression or injection molding from the melt. An alternative and promissing route for processing fluorocarbon films is the use of a low- pressure plasma: This technique can be employed for plasma polymerization of suitable fluorocarbon monomers and for controlled etching of fluorocarbon materials. In the present work, we present the characteristics of plasma-polymerized tetrafluoroethylene layers with a refractive index of approximately 1.4. Reactive ion etching in an N2O plasma is used for patterning these layers, and also the spin-coated Teflon AF films with a refractive index of around 1.3. Possibilities of fabricating passive and active polymer waveguide devices from flurocarbon polymers are discussed, and estimates of the expected waveguide performance are presented.

  13. Long Term Aging of Elastomers: Chemorheology of Viton B Fluorocarbon Elastomer

    NASA Technical Reports Server (NTRS)

    Kalfayan, S. H.; Silver, R. H.; Mazzeo, A. A.; Lui, S. T.

    1972-01-01

    The continuation of a study to ascertain the nature, extent, and the rate of chemical changes that take place in certain selected elastomers is reported. Under discussion is Viton B, regarded as a temperature and fuel resistant fluorocarbon rubber. The kinetic analysis of the chemical stress relaxation, and infrared and gel permeation chromatography analysis results are discussed.

  14. Effective and efficient surfactant for CO2 having only short fluorocarbon chains.

    PubMed

    Sagisaka, Masanobu; Iwama, Shuho; Yoshizawa, Atsushi; Mohamed, Azmi; Cummings, Stephen; Eastoe, Julian

    2012-07-31

    A previous study (Langmuir2011, 27, 5772) found the fluorinated double-tail sulfogulutarate 8FG(EO)(2) to act as a superefficient solubilizer for water in supercritical CO(2) (W/CO(2)) microemulsions. To explore more economic CO(2)-philic surfactants with high solubilizing power as well as rapid solubilization rates, the effects of fluorocarbon chain length and linking group were examined with sodium 1,5-bis(1H,1H,2H,2H-perfluoroalkyloxy)-1,5-dioxopentane-2-sulfonates (nFG(EO)(2), fluorocarbon chain length n = 4, 6, 8) and sodium 1,4-bis(1H,1H,2H,2H-perfluoroalkyloxy)-1,4-dioxobutane-2-sulfonate (nFS(EO)(2), n = 4, 8). Visual observation and UV-vis spectral measurements with methyl orange as a reporter dye indicated a maximum water-to-surfactant molar ratio (W(0)) in the microemulsions, which was 60-80 for nFG(EO)(2) and 40-50 for nFG(EO)(2). Although it is normally expected that high solubilizing power requires long fluorocarbon surfactant chains, the shortest fluorocarbon 4FG(EO)(2) interestingly achieved the highest W(0) (80) transparent single-phase W/CO(2) microemulsion. In addition, a very rapid solubilization of loaded water into CO(2) was observed for 4FG(EO)(2) even at a high W(0) of ~80. PMID:22738302

  15. Alveolar gas concentrations of fluorocarbons-11 and -12 in man after use of pressurized aerosols

    PubMed Central

    Draffan, G. H.; Dollery, C. T.; Williams, Faith M.; Clare, R. A.

    1974-01-01

    Draffan, G. H., Dollery, C. T., Williams, Faith M., and Clare, R. A. (1974).Thorax, 29, 95-98. Alveolar gas concentrations of fluorocarbons-11 and -12 in man after use of pressurized aerosols. In dogs, inhalation of fluorocarbon aerosol propellants sensitizes the heart to arrhythmias provoked by intravenous injection of adrenaline. In this research, the concentrations of fluorocarbons-11 and -12, CCl3F and CCl2F2, have been measured in alveolar gas in man after using pressurized aerosol inhalers. Fluorocarbons were measured breath by breath using an AEI MS12 mass-spectrometer modified to allow sampling from a respiratory mouthpiece. After a single inhalation from an inhaler by six normal volunteers the mean concentration of fluorocarbon-12 in alveolar gas had reached 5·5 μg/ml, giving a mean apparent volume of distribution of 7·94 litres compared with the mean predicted total lung capacity of 6·61 litres. These results suggest that most of the fluorocarbon expelled from the inhaler entered the alveolar gas. The mean alveolar concentration of F-11 was 2·7 μg/ml and the mean apparent volume of distribution was 12·46 litres. The higher volume of distribution with the less volatile F-11 probably reflects the amount dissolved in lung tissue and pulmonary capillary blood. Similar results were obtained in two patients with obstructive airways disease. One volunteer took an inhalation on every breath up to two minutes and reached an alveolar concentration of F-11 of 29·6 μg/ml and of F-12 of 66·9 μg/ml. The concentration of F-11 required to sensitize the dog heart to arrhythmias was 68 μg/ml. Thus there should be no hazards from the amount entering alveolar gas in normal use after a single inhalation. Inhalation upon every breath over a period raises the alveolar concentration to one approaching that which, in the dog, might be hazardous. PMID:4825557

  16. Application of Chemically Adsorbed Fluorocarbon Film with Highly Durability as a Mold Release Agent

    NASA Astrophysics Data System (ADS)

    Yamamoto, Hiroyuki; Ohkubo, Yuji; Ogawa, Kazufumi; Utsumi, Kunihiro

    In this study, the physical performance (adhesion resistance, heat resistance, abrasion resistance, chemical resistance) extremely thin, highly durable and chemically adsorbed fluorocarbon film with low surface energy on the metal surface (the thickness is about 1 nm order.) was evaluated, and the evaluation results (durability, demolding resistance) on the actual injection molding performance up to 100,000 shots using a test mold were reported. The demolding resistance could be drastically decreased without losing the mold shape and dimensional accuracy by using the chemically adsorbed and highly durable fluorocarbon film. From these results, this technique should be useful for molding various elastomers such as silicone and urethane resin which are difficult to release from a mold for making high precision products such as optical components and chemical chips.

  17. Comparison of stratospheric ozone destruction by fluorocarbons 11, 12, 21, and 22

    NASA Technical Reports Server (NTRS)

    Robbins, D. E.; Stolarski, R. S.

    1976-01-01

    Measured photoabsorption cross sections for fluorocarbons (FC) 11, 12, 21, and 22 are presented for the wavelength region from 1740 A to about 2200 A. Solar radiation in this region dissociates these molecules in the stratosphere releasing atomic chlorine which participates in catalytic reactions that destroy ozone. Photolysis by solar UV is the only known loss mechanism for FC11 and FC12. However, FC21, and FC22 also react with OH in the troposphere reducing the amount of ground level releases which reach the stratosphere. Calculations comparing the steady state stratospheric C1X due to equal release rates of fluorocarbons 11, 12, 21, and 22 are presented using a range of OH profiles and eddy diffusion coefficients. These calculations indicate approximately a factor of 20 to 450 less C1X in the stratosphere for FC21 and a factor of 40 to 130 for FC22, compared to an equal release rate of FC11 and FC12.

  18. Nano-ring-shape growth of fluorocarbon macromolecules during SiO2 etching.

    PubMed

    Lee, Sang Hwui; Lu, Jian-Qiang

    2010-04-16

    A unique nanoscale ring-shape pattern of fluorocarbon macromolecules grown during SiO2 reactive ion etching (RIE) is presented. This pattern was discovered after SiO2 RIE using trifluoromethane (CHF3) and oxygen. Typical dimensions of the ring-type fluorocarbon structure are found to be approximately 50 nm in diameter, approximately 10 nm in wall thickness, and approximately 50 nm in height in this study. The ring-shape structure grows towards a tube-shape structure up to 500 nm. Morphological studies are also presented with various plasma etching parameters. This experiment shows that oxygen-rich RIE etching produces more ring-type structures. This could be used as a nanoscale template for other applications. PMID:20332556

  19. Nano-ring-shape growth of fluorocarbon macromolecules during SiO2 etching

    NASA Astrophysics Data System (ADS)

    Hwui Lee, Sang; Lu, Jian-Qiang

    2010-04-01

    A unique nanoscale ring-shape pattern of fluorocarbon macromolecules grown during SiO2 reactive ion etching (RIE) is presented. This pattern was discovered after SiO2 RIE using trifluoromethane (CHF3) and oxygen. Typical dimensions of the ring-type fluorocarbon structure are found to be ~ 50 nm in diameter, ~ 10 nm in wall thickness, and ~ 50 nm in height in this study. The ring-shape structure grows towards a tube-shape structure up to 500 nm. Morphological studies are also presented with various plasma etching parameters. This experiment shows that oxygen-rich RIE etching produces more ring-type structures. This could be used as a nanoscale template for other applications.

  20. The corrosion phenomena in the coin cell BR2325 of the ``superstoichiometric fluorocarbon-lithium'' system

    SciTech Connect

    Mitkin, V.N.; Galkin, P.S.; Denisova, T.N.

    1998-07-01

    It was noted at the earlier study and at the longer observations of the novel various types of superstoichiometric fluorocarbon materials CF{sub 1+x}, where x = 0.1--0.33 (FCM) and their behavior, that despite of their known hygroscopity during a storage of samples in laboratory and technological utensils nevertheless occurs an appreciable sorption of atmospheric moisture. The color of samples does not change but sometimes there appears a smell of hydrogen fluoride and even corrosion of glasswares at a long storage. On the basis of these facts was assumed that at a long storage the slow reactions of HF producing with a sorption moisture can proceed. This phenomena is necessary to take into account for successful manufacturing of long life lithium cells based on superstoichiometric fluorocarbon composite cathodes (FCC). The chemistry of such slow hydrolytic process and especially of processes which can proceed at manufacturing of FCC earlier was not investigated also of any data in the literature in this occasion is not present. Just for this reason the authors undertook a study of the corrosion phenomena which can proceed in industrial sources of a current at a long storage under influence of slow hydrolysis of C-F bonds by moisture. The goal of the study was to search long term damages in the slightly wet FCM and based on these materials cathodic composites for fluorocarbon-lithium cells. As a model for corrosion process investigation they have chosen a standard coin lithium battery of a type BR2325.

  1. Absorption and recovery of n-hexane in aqueous solutions of fluorocarbon surfactants.

    PubMed

    Xiao, Xiao; Yan, Bo; Fu, Jiamo; Xiao, Xianming

    2015-11-01

    n-Hexane is widely used in industrial production as an organic solvent. As an industrial exhaust gas, the contribution of n-hexane to air pollution and damage to human health are attracting increasing attention. In the present study, aqueous solutions of two fluorocarbon surfactants (FSN100 and FSO100) were investigated for their properties of solubilization and dynamic absorption of n-hexane, as well as their capacity for regeneration and n-hexane recovery by thermal distillation. The results show that the two fluorocarbon surfactants enhance dissolution and absorption of n-hexane, and their effectiveness is closely related to their concentrations in solution. For low concentration solutions (0.01%-0.30%), the partition coefficient decreases dramatically and the saturation capacity increases significantly with increasing concentration, but the changes for both are more modest when the concentration is over 0.30%. The FSO100 solution presents a smaller partition coefficient and a greater saturation capacity than the FSN100 solution at the same concentration, indicating a stronger solubilization for n-hexane. Thermal distillation is a feasible method to recover n-hexane from these absorption solutions, and to regenerate them. With 90sec heating at 80-85C, the recovery of n-hexane ranges between 81% and 85%, and the regenerated absorption solution maintains its original performance during reuse. This study provides basic information on two fluorocarbon surfactants for application in the treatment of industrial n-hexane waste gases. PMID:26574100

  2. Synthesis and applications of vegetable oil-based fluorocarbon water repellent agents on cotton fabrics.

    PubMed

    Zhao, Tao; Zheng, Junzhi; Sun, Gang

    2012-06-01

    Vegetable oil-based fluorocarbon water repellent agents were prepared by chemical modifications of different vegetable oils - soybean and linseed oils through several reactions, including saponification, acidification, acylation of vegetable oil and trans-esterification with 2,2,2-trifluoroethanol and 2,2,3,3-tetrafluoropropanol. The resulted fluorocarbon agents were then copolymerized with styrene. The structures of the vegetable oil based agents were characterized by FT-IR and NMR. By evaluating water contact angle and time of water disappearance on cotton fabrics, as well as whiteness and breaking strength of cotton fabrics that were treated by these agents, optimum fabric finishing conditions were explored. The cotton fabrics finished with the vegetable oil-based fluorocarbon agents showed excellent water repellency, while other properties of the cotton fabrics declined to certain level. The linseed oil-based tetrafluoropropanol water repellent agent displayed the highest water repellency among all modified oils. All the treated fabrics exhibited good durability of water repellency. The linseed oil-based tetrafluoropropanol water repellent agent demonstrated the best durability among all repellent agents. PMID:24750623

  3. Effect of two hydrocarbon and one fluorocarbon surfactant mixtures on the surface tension and wettability of polymers.

    PubMed

    Szymczyk, Katarzyna; Gonzlez-Martn, Maria Luisa; Bruque, Jose Morales; Ja?czuk, Bronis?aw

    2014-03-01

    The advancing contact angle of water, formamide and diiodomethane on polytetrafluoroethylene (PTFE) and polymethyl methacrylate (PMMA) surfaces covered with the film of ternary mixtures of surfactants including p-(1,1,3,3-tetramethylbutyl) phenoxypoly(ethyleneglycols), Triton X-100 (TX100) and Triton X-165 (TX165) and the fluorocarbon surfactants, Zonyl FSN-100 (FSN100) or Zonyl FSO-100 (FSO100) was measured. The obtained results were used for the surface tension of PTFE and PMMA covered with this film determination from the Young equation on the basis of van Oss et al. and Neumann et al. approaches to the interfacial tension. The surface tension of PTFE and PMMA was also determined using the Neumann et al. equation and the contact angle values for the aqueous solutions of the above mentioned ternary surfactants mixtures which were taken from the literature. As follows from our calculations mainly the presence of the fluorocarbon surfactant in the mixture considerably changes the surface properties of PTFE and PMMA causing that in contrast to hydrocarbon surfactants and their mixtures there is no linear dependence between adhesion and surface tension in the whole range of concentration of the ternary mixtures of surfactants including the fluorocarbon one. The behavior of fluorocarbon surfactants at the polymer-air and polymer-water interfaces is quite different from those of hydrocarbons. In the case of fluorocarbon surfactants not only adsorption but also sorption can occur on the polymer surface. PMID:24407675

  4. In situ analysis of aqueous structure and adsorption at fluorocarbon, hydrocarbon and mineral surfaces

    NASA Astrophysics Data System (ADS)

    Hopkins, Adam Justin

    Altering and controlling the properties of solid surfaces in aqueous or other liquid phase environments has been a sought after objective for decades. With the discovery of chemisorbed self-assembled monolayers, this dream has become a reality. Oxide and metal surfaces can now be readily coated with an array of commercially available products to produce a desired fnctionality. The presence of these coatings on solid surfaces affects properties of the interfacial region by altering interfacial electrostatic fields, changing the structure of interfacial water molecules and altering the interactions of adsorbed species. This dissertation reports on in situ studies of adsorption at several solid/aqueous interfaces using vibrational sum-frequency spectroscopy, a surface specific technique. These studies are augmented by the use of atomic force microscopy and contact angle goniometry to characterize the prepared surfaces and their interactions with adsorbates. The studies investigate how changes in the surface structure and chemistry, as well as the bulk aqueous phase, affect interfacial structure. The studies within are primarily focused on the interactions of water with bare and functionalized fused silica and the relationship between the aqueous phase composition and the structure of fluorocarbon and hydrocarbon self-assembled monolayers. The variations in aqueous structure are then examined in detail using ionic strength controlled experiments to understand the direct interactions of water hydrophobically coated silica. This analysis is followed by an investigation of the competitive adsorption of methanol and water at fluorocarbon and hydrocarbon monolayers which show spectroscopic signatures of the interaction strength between fluorocarbons and hydrocarbons. Further studies are performed using butylammonium chloride to verify these spectroscopic signatures and reveal different molecular structures of adsorbed species at chemically different hydrophobic surfaces. Lastly, specific ion effects on the CaF2/water interface are shown using equilibrium and time-resolved sum-frequency spectroscopy. The results of all these studies have implications for an array of surface chemical applications from mineral flotation to biocompatibility. This dissertation includes previously published co-authored material.

  5. Fluorocarbon nano-coating of polyester fabrics by atmospheric air plasma with aerosol

    NASA Astrophysics Data System (ADS)

    Leroux, F.; Campagne, C.; Perwuelz, A.; Gengembre, L.

    2008-04-01

    A fluorocarbon coating was deposited on polyester (PET) woven fabric using pulse discharge plasma treatment by injecting a fluoropolymer directly into the plasma dielectric barrier discharge. The objective of the treatment was to improve the hydrophobic properties as well as the repellent behaviour of the polyester fabric. Plasma treatment conditions were optimised to obtain optimal hydrophobic properties which were evaluated using water contact angle measurement as well as spray-test method at the polyester fabric surface. The study showed that adhesion of the fluoropolymer to the woven PET was greatly enhanced by the air plasma treatment. X-ray photoemission spectroscopy (XPS) analyses revealed chemical surface modifications occurring after the plasma treatments.

  6. Experimental Study on the Application as the Mold Release Agent of a Chemically Adsorbed Fluorocarbon Film

    NASA Astrophysics Data System (ADS)

    Yamamoto, Hiroyuki; Ohkubo, Yuji; Ogawa, Kazufumi; Utsumi, Kunihiro

    In this study, the use of an extremely thin and chemically adsorbed fluorocarbon film with no influences on the dimension accuracy of the mold geometries on an injection mold (The thickness is about 1 nanometer order.) was experimentally studied as a great releasing agent to reduce the ejection resistance without any influences on the dimensional accuracy of the mold geometries. As a result, this surface treatment on the mold was practically confirmed not only to be very beneficial for the polymers those are difficult to release from the mold surface such as silicone, urethane and elastomers, but also to be useful for making high precision products such as optical components and chemical chips.

  7. Disappearance of fuel hydrazine vapors in fluorocarbon-film environmental chambers. Experimental observations and kinetic modeling

    SciTech Connect

    Stone, D.A.; Wiseman, F.L.; Kilduff, J.E.; Koontz, S.L.; Davis, D.D.

    1989-03-01

    Fluorocarbon-film environmental chambers, of the type often employed in air pollution studies, have been used to investigate the stability of the fuel hydrazines (hydrazine, methylhydrazine, and 1,1-dimethylhydrazine) with respect to atmospheric oxidation. These studies have shown that the observed disappearance of fuel hydrazine vapors in these chambers is caused by physical loss processes rather than oxidation. Vapor-phase decay is affected by chamber size, water content of the matrix gas, and previous chamber experiments. A kinetic model has been developed that incorporates adsorption, permeation, and surface site concentration to fit the observed decay data.

  8. Synthesis and self-assembly of fluorocarbon- and hydrocarbon-modified hydrophilic polymers. Final report

    SciTech Connect

    Hogen-Esch, T.E.

    1996-11-01

    Over the past 3 years, work was done in several areas: effect of spacer lengths on degree of association of hydrophobically modified polyacrylamides; fluorocarbon mediated association of R{sub F}- substituted polyacrylamide-2-(acrylamido)-2-methyl-propane sodium sulfonate copolymers; hydrophobic association in R{sub F}(R{sub H})-modified poly(N,N-dimethylacrylamide)(PDMA) and polyvinylpyrrolidone; synthesis of R{sub F}-containing poly(N- isopropyl acrylamide)`s; synthesis of HM narrow MWD telechelics PDMA and PDMA block copolymers; and studies of telechelic R{sub F}(R{sub H}) derivatives of polyethyleneglycols. 15 refs, 7 figs, 2 tabs.

  9. Mesoporous Fluorinated Metal-Organic Frameworks with Exceptional Adsorption of Fluorocarbons and CFCs.

    PubMed

    Chen, Teng-Hao; Popov, Ilya; Kaveevivitchai, Watchareeya; Chuang, Yu-Chun; Chen, Yu-Sheng; Jacobson, Allan J; Miljani?, Ognjen

    2015-11-16

    Two mesoporous fluorinated metal-organic frameworks (MOFs) were synthesized from extensively fluorinated tritopic carboxylate- and tetrazolate-based ligands. The tetrazolate-based framework MOFF-5 has an accessible surface area of 2445?m(2) ?g(-1) , the highest among fluorinated MOFs. Crystals of MOFF-5 adsorb hydrocarbons, fluorocarbons, and chlorofluorocarbons (CFCs)-the latter two being ozone-depleting substances and potent greenhouse species-with weight capacities of up to 225?%. The material exhibits an apparent preference for the adsorption of non-spherical molecules, binding unusually low amounts of both tetrafluoromethane and sulfur hexafluoride. PMID:26423312

  10. Structure and Depletion at Fluorocarbon and Hydrocarbon/Water Liquid/Liquid Interfaces

    SciTech Connect

    Kashimoto,K.; Yoon, J.; Hou, B.; Chen, C.; Lin, B.; Aratono, M.; Takiue, T.; Schlossman, M.

    2008-01-01

    The results of x-ray reflectivity studies of two oil/water (liquid/liquid) interfaces are inconsistent with recent predictions of the presence of a vaporlike depletion region at hydrophobic/aqueous interfaces. One of the oils, perfluorohexane, is a fluorocarbon whose superhydrophobic interface with water provides a stringent test for the presence of a depletion layer. The other oil, heptane, is a hydrocarbon and, therefore, is more relevant to the study of biomolecular hydrophobicity. These results are consistent with the subangstrom proximity of water to soft hydrophobic materials.

  11. Properties of solid polymer electrolyte fluorocarbon film. [used in hydrogen/oxygen fuel cells

    NASA Technical Reports Server (NTRS)

    Alston, W. B.

    1973-01-01

    The ionic fluorocarbon film used as the solid polymer electrolyte in hydrogen/oxygen fuel cells was found to exhibit delamination failures. Polarized light microscopy of as-received film showed a lined region at the center of the film thickness. It is shown that these lines were not caused by incomplete saponification but probably resulted from the film extrusion process. The film lines could be removed by an annealing process. Chemical, physical, and tensile tests showed that annealing improved or sustained the water contents, spectral properties, thermo-oxidative stability, and tensile properties of the film. The resistivity of the film was significantly decreased by the annealing process.

  12. Structure and Depletion at Fluorocarbon and Hydrocarbon/Water Liquid/Liquid Interfaces

    NASA Astrophysics Data System (ADS)

    Kashimoto, Kaoru; Yoon, Jaesung; Hou, Binyang; Chen, Chiu-Hao; Lin, Binhua; Aratono, Makoto; Takiue, Takanori; Schlossman, Mark L.

    2008-08-01

    The results of x-ray reflectivity studies of two oil/water (liquid/liquid) interfaces are inconsistent with recent predictions of the presence of a vaporlike depletion region at hydrophobic/aqueous interfaces. One of the oils, perfluorohexane, is a fluorocarbon whose superhydrophobic interface with water provides a stringent test for the presence of a depletion layer. The other oil, heptane, is a hydrocarbon and, therefore, is more relevant to the study of biomolecular hydrophobicity. These results are consistent with the subangstrom proximity of water to soft hydrophobic materials.

  13. Gas Adsorption Properties of Fluorocarbon Thin Films Prepared Using Three Different Types of RF Magnetron Sputtering Systems

    NASA Astrophysics Data System (ADS)

    Satoru Iwamori,; Norihiko Hasegawa,; Satoshi Yano,; Kazutoshi Noda,

    2010-04-01

    Fluorocarbon thin films were deposited onto a quartz crystal with a poly(tetrafluoroethylene) target using three different types of RF magnetron sputtering systems with strong, weak, and unbalanced magnetic fields. The adsorption properties of these thin films for water, ethanol, acetone, acetaldehyde, toluene, and methyl salicylate were evaluated using the quartz crystal microbalance (QCM) method in order to characterize the surface properties of these thin films. These thin films have low sensitivities to non-polar solvents that contain methyl and aromatic groups, and high sensitivities to polar solvents that contain carbonyl and hydroxyl groups. Chemical structures, especially, polar moieties in these fluorocarbon thin films would affect the gas adsorption properties.

  14. Real-Time Trace Gas Sensing of Fluorocarbons using a Swept-wavelength External Cavity Quantum Cascade Laser

    SciTech Connect

    Phillips, Mark C.; Taubman, Matthew S.; Bernacki, Bruce E.; Cannon, Bret D.; Stahl, Robert D.; Schiffern, John T.; Myers, Tanya L.

    2014-05-04

    We present results demonstrating real-time sensing of four different fluorocarbons at low-ppb concentrations using an external cavity quantum cascade laser (ECQCL) operating in a swept-wavelength configuration. The ECQCL was repeatedly swept over its full tuning range at a 20 Hz rate with a scan rate of 3535 cm-1/s, and a detailed characterization of the ECQCL scan stability and repeatability is presented. The sensor was deployed on a mobile automotive platform to provide spatially resolved detection of fluorocarbons in outdoor experiments. Noise-equivalent detection limits of 800-1000 parts-per-trillion (ppt) are demonstrated for 1 s integration times.

  15. Synthesis, Thermal Properties and Cytotoxicity Evaluation of Hydrocarbon and Fluorocarbon Alkyl β-D-xylopyranoside Surfactants

    PubMed Central

    Xu, Wenjin; Osei-Prempeh, Gifty; Lema Herrera, Fresia C.; Oldham, E. Davis; Aguilera, Renato J.; Parkin, Sean; Rankin, Stephen E.; Knutson, Barbara L.; Lehmler, Hans-Joachim

    2011-01-01

    Alkyl β-D-xylopyranosides are highly surface active, biodegradable surfactants that can be prepared from hemicelluloses and are of interest for use as pharmaceuticals, detergents, agrochemicals and personal care products. To gain further insights into their structure-property and structure-activity relationships, the present study synthesized a series of hydrocarbon (-C6H13 to -C16H33) and fluorocarbon (-(CH2)2C6F13) alkyl β-D-xylopyranosides in four steps from D-xylose by acylation or benzoylation, bromination, Koenigs-Knorr reaction and hydrolysis, with the benzoyl protecting group giving better yields compared to the acyl group in the Koenigs-Knorr reaction. All alkyl β-D-xylopyranosides formed thermotropic liquid crystals. The phase transition of the solid crystalline phase to a liquid crystalline phase increased linearly with the length of the hydrophobic tail. The clearing points were near constant for alkyl β-D-xylopyranosides with a hydrophobic tail ≥ 8, but occurred at a significantly lower temperature for hexyl β-D-xylopyranoside. Short and long-chain alkyl β-D-xylopyranosides displayed no cytotoxicity at concentration below their aqueous solubility limit. Hydrocarbon and fluorocarbon alkyl β-D-xylopyranosides with intermediate chain length displayed some toxicity at millimolar concentrations due to apoptosis. PMID:22207000

  16. Single-Step Fluorocarbon Plasma Treatment-Induced Wrinkle Structure for High-Performance Triboelectric Nanogenerator.

    PubMed

    Cheng, Xiaoliang; Meng, Bo; Chen, Xuexian; Han, Mengdi; Chen, Haotian; Su, Zongming; Shi, Mayue; Zhang, Haixia

    2016-01-01

    A triboelectric nanogenerator (TENG) has been thought to be a promising method to harvest energy from environment. To date, the utilization of surface structure and material modification has been considered the most effective way to increase its performance. In this work, a wrinkle structure based high-performance TENG is presented. Using the fluorocarbon plasma treatment method, material modification and surface structure are introduced in one step. The output ability of TENG is dramatically enhanced. After the optimization of plasma treatment, the maximum current and surface charge density are 182 μA about 165 μC m(-2) . Compared with untreated TENG, the wrinkle structure makes the current and surface charge density increase by 810% and 528%, separately. X-ray photoelectron spectroscopy is employed to analyze the chemical modification mechanism of this fluorocarbon plasma treatment. Facilitated by its high output performance, this device could directly light 76 blue light emitting diodes under finger typing. The output electric energy could be stored then utilized to power a commercial calculator. As a result of the simple fabrication process and high output ability, devices fabricated using this method could bring forward practical applications using TENGs as power sources. PMID:26619271

  17. Molecular-thermodynamic framework to predict the micellization behavior of mixtures of fluorocarbon-based and hydrocarbon-based surfactants.

    PubMed

    Iyer, Jaisree; Blankschtein, Daniel

    2014-03-01

    We present a molecular-thermodynamic (MT) framework to predict the micellization properties of mixtures of fluorocarbon-based and hydrocarbon-based surfactants. Practically, this mixing reduces the use of fluorinated surfactants in the surfactant formulation, thereby addressing environmental concerns associated with the non-biodegradability and toxicity of fluorinated surfactants. The micellization properties of these mixtures are affected by the enthalpic interactions between the fluorocarbon and hydrocarbon surfactant tails. Consequently, the MT framework incorporates an enthalpy of mixing contribution estimated using regular solution theory (RST). The RST interaction parameter is estimated on the basis of phase equilibrium data. The MT framework also makes allowance for the coexistence of two types of micelles in solution to account for experimental findings which suggest that mixtures of fluorocarbon-based and hydrocarbon-based surfactants can form two types of micelles. Furthermore, the model used to calculate the packing free energy of binary mixtures of surfactant tails is generalized to incorporate the difference in the tail volumes, tail lengths, and conformational energies of the fluorocarbon and hydrocarbon tails. The MT framework is then used to predict micelle population distributions, critical micelle concentrations, and optimal micelle compositions for various mixtures of fluorocarbon-based and hydrocarbon-based surfactants, and the predictions are compared with the corresponding experimental values. While many of the predictions compare well with experiment, some of the experimentally observed trends are not reproduced by the MT framework. Ways to eliminate the discrepancy between theory and experiment are discussed. We also find that prediction of the micelle population distribution is very sensitive to the magnitude of the RST interaction parameter used to calculate the enthalpy of mixing, where an increase in the RST interaction parameter results in sharper peaks in the predicted bimodal micelle population distribution. In addition to the quantitative prediction of micellization properties, the MT framework provides useful physical insight about the reasons behind the differences in the micellization properties of various surfactant mixtures. PMID:24512047

  18. Corrosion protection ability of plasma-deposited amorphous hydrogenated carbon and fluorocarbon films

    NASA Astrophysics Data System (ADS)

    Srividya, C.; Sunkara, M.; Babu, S. V.

    1997-10-01

    Hydrogenated diamond-like carbon and fluorocarbon films, deposited in a radio-frequency (rf) plasma reactor, have high chemical inertness and high electrical resistivity. These films, deposited on aluminum and type 301 stainless steel substrates at several rf power and feed gas flow rates using different gas phase precursors, were characterized for their pinhole density and stability with exposure to 0.6 M NaCl and 0.1 M NaCl and 0.1 M Na2SO4 solutions using electrochemical impedance spectroscopy and potentiostatic techniques, respectively. The results from electrochemical characterizations with salt water exposure indicated that films with high effective pore resistances (>108 ? cm2)* and high stability with exposure (<10% changes in capacitance values) can be obtained over a narrow range of process conditions and gas phase compositions.

  19. Overcoming inactivation of the lung surfactant by serum proteins: a potential role for fluorocarbons?

    PubMed

    Krafft, Marie Pierre

    2015-08-14

    In many pulmonary conditions serum proteins interfere with the normal adsorption of components of the lung surfactant to the surface of the alveoli, resulting in lung surfactant inactivation, with potentially serious untoward consequences. Here, we review the strategies that have recently been designed in order to counteract the biophysical mechanisms of inactivation of the surfactant. One approach includes protein analogues or peptides that mimic the native proteins responsible for innate resistance to inactivation. Another perspective uses water-soluble additives, such as electrolytes and hydrophilic polymers that are prone to enhance adsorption of phospholipids. An alternative, more recent approach consists of using fluorocarbons, that is, highly hydrophobic inert compounds that were investigated for partial liquid ventilation, that modify interfacial properties and can act as carriers of exogenous lung surfactant. The latter approach that allows fluidisation of phospholipid monolayers while maintaining capacity to reach near-zero surface tension definitely warrants further investigation. PMID:26110877

  20. ToF-SIMS and AFM studies of low- k dielectric etching in fluorocarbon plasmas

    NASA Astrophysics Data System (ADS)

    Lazzeri, P.; Hua, X.; Oehrlein, G.; Iacob, E.; Barozzi, M.; Bersani, M.; Anderle, M.

    2006-07-01

    Surface modifications and etching mechanisms of several nanoporous low- k dielectrics (spin-on and PECVD) using fluorocarbon plasmas have been investigated by ToF-SIMS and AFM and compared with those of SiO 2. The results show a fluoropolymer film growing on the materials using highly polymerizing discharges (C 4F 8). The fluoropolymers are converted into fluoroether-like compounds upon etching low-porosity dielectrics in ion-rich C 4F 8/90% Ar plasmas. These layers mitigate the influx of plasma species and inhibit the etching rate. No surface roughness develops for these conditions, keeping the plasma/material interaction regime stationary. On the other hand, the surface coverage by fluoroethers is reduced when the porosity exceeds a given threshold. Consequently, direct plasma/dielectric interactions including ion bombardment take place, causing an increase of the etching rate, surface roughening and severe modifications of the pristine dielectric.

  1. Review of ultraviolet absorption cross sections of a series of alternative fluorocarbons

    NASA Technical Reports Server (NTRS)

    Molina, Mario J.

    1990-01-01

    Solar photolysis is likely to contribute to the stratospheric destruction of those alternative fluorocarbons (HFC's) which have two or more chlorine atoms bonded to the same carbon atom. Two of the eight HFC's considered here fall into this category, namely HFC-123 and HFC141b. For these two species there is good agreement among the various measurements of the ultraviolet cross sections in the wavelength region which is important for atmospheric photodissociation, that is, around 200 nm. There is also good agreement for HFC-124, HFC-22 and HFC-142b. These are the three species which contain one chlorine atom per molecule. The agreement in the measurements is poor for the other species, i.e., those that do not contain chlorine, except in so far as to corroborate that solar photolysis should be negligible relative to destruction by hydroxyl radicals.

  2. Correlation of elastohydrodynamic film thickness measurements for fluorocarbon type 2 ester, and polyphenyl ether lubricants

    NASA Technical Reports Server (NTRS)

    Loewenthal, S. H.; Parker, R. J.; Zaretsky, E. V.

    1974-01-01

    A minimum films thickness correlation applicable to heavily loaded elastohydrodynamic (EHD) contacts was formulated from experimental data obtained by an X-ray transmission technique. The correlation, based on data generated with fluorocarbon, type II ester, and polyphenyl ether lubricants, extends a previous analysis developed from data for a synthetic paraffinic oil. The resulting correlation represents the data of the four lubricants reasonably well over a large range of operating conditions. Contained within the derived relation is a factor to account for the high-load dependence displayed by the measurements beyond that which is provided for by the theory. Thermal corrections applied to a commonly used film thickness formula showed little improvement to the general disagreement that exists between theory and test. Choice of contact geometry and material are judged to have a relatively mild influence on the form of the semiempirical model.

  3. Hierarchical ZnO particles grafting by fluorocarbon polymer derivative: Preparation and superhydrophobic behavior

    NASA Astrophysics Data System (ADS)

    Gao, Dahai; Jia, Mengqiu

    2015-07-01

    Superhydrophobic surfaces on the basis of hierarchical ZnO particles grafted by fluoroethylene-vinylether (FEVE) polymer derivative were prepared using a facile, mild and low-cost method. X-ray diffraction (XRD) and scanning electron microscope (SEM) revealed that the resulting ZnO particles via hydrothermal process exhibit micro-nano dual-scale morphology with high purity under a suitable surfactant amount and alkali concentration. The grafting of FEVE derivative was confirmed by Fourier transform infrared spectroscopy (FTIR) and energy-dispersive X-ray spectrometer (EDS), suggesting that hierarchical surface of ZnO particles was an imported monomolecular layer of fluorocarbon polymer. The obtained surface fabricated by drop-casting shows considerably high contact angle and good resistance to water immersion. The wetting behavior in this work was furthermore analyzed by theoretical wetting model. This work demonstrates that the sufficient low-wettable surface and high roughness both take a vital role in the superhydrophobic behavior.

  4. A Microfluidic Cell Co-Culture Platform with a Liquid Fluorocarbon Separator

    PubMed Central

    Brewer, Bryson M.; Shi, Mingjian; Edd, Jon F.; Webb, Donna J.; Li, Deyu

    2014-01-01

    A microfluidic cell co-culture platform that uses a liquid fluorocarbon oil barrier to separate cells into different culture chambers has been developed. Characterization indicates that the oil barrier could be effective for multiple days, and a maximum pressure difference between the oil barrier and aqueous media in the cell culture chamber could be as large as ?3.43 kPa before the oil barrier fails. Biological applications have been demonstrated with the separate transfection of two groups of primary hippocampal neurons with two different fluorescent proteins and subsequent observation of synaptic contacts between the neurons. In addition, the quality of the fluidic seal provided by the oil barrier is shown to be greater than that of an alternative solid-PDMS valve barrier design by testing the ability of each device to block low molecular weight CellTracker dyes used to stain cells in the culture chambers. PMID:24420386

  5. Fluorocarbon-23 measure of cat cerebral blood flow by nuclear magnetic resonance

    SciTech Connect

    Ewing, J.R.; Branch, C.A.; Fagan, S.C.; Helpern, J.A.; Simkins, R.T.; Butt, S.M.; Welch, K.M. )

    1990-01-01

    We employed fluorocarbon-23 (trifluoromethane) as a nuclear magnetic resonance gaseous indicator of cerebral blood flow in seven cats. Pulsed inhalation of this indicator and switching between two coils allowed the acquisition of both an arterial input and a cerebral response function, making possible multicompartmental curve fits to cerebral uptake and clearance data. The brain:blood partition coefficient for trifluoromethane was 0.9 for both gray and white matter. Fast-compartment blood flows were normal and showed appropriate CO{sub 2} reactivity. Slow-compartment blood flows did not demonstrate CO{sub 2} reactivity, probably because cranial as well as white-matter blood flows were lumped together in the slow compartment. Although cerebral blood flow was stable during administration of 60% trifluoromethane, the compound did prove to be a mild cardiac sensitizer to epinephrine in five cats.

  6. Assessment of effects on vegetation of degradation products from alternative fluorocarbons

    NASA Technical Reports Server (NTRS)

    Mccune, D. C.; Weinstein, L. H.

    1990-01-01

    Concern with the effects of fluorides on plants has been devoted to that resulting from dry deposition (mainly with reference to gaseous HF and secondarily with particulate forms). The occurrence of precipitation as rain or mist and the presence of dew or free water on the foliage has mainly been considered with respect to their effects on the accumulation of air-borne fluoride and not with fluoride in wet deposition. That is, precipitation has been viewed primarily with respect to its facilitation of the solution and subsequent absorption of deposits by the foliar tissues or its elution of deposited fluoride from foliage. Accordingly, our evaluation of inorganic fluoride from fluorocarbon degradation rests upon a comparison with what is known about the effects of industrial emissions and what could be considered the natural condition.

  7. Molecular composition of films and solid particles polymerized in fluorocarbon plasmas

    NASA Astrophysics Data System (ADS)

    Takahashi, Kazuo; Tachibana, Kunihide

    2001-01-01

    In fluorocarbon (C4F8) plasmas, formation mechanisms of polymers were investigated by the characterization with x-ray photoelectron spectroscopy (XPS) and gel permeation chromatography (GPC). The molecular compositions of the polymers in the films deposited on the substrate and in the particles formed in the gas phase were elucidated by these chemical analyses. The XPS results showed that the particles were carbon-rich and composed of highly branched molecules in contrast to the film composition. From the GPC measurements, the particles were found to contain ultrahigh mass polymers, whose molecular weights were around 100 000. On the contrary, the deposited film contained polymers with molecular weights distributed below 2000, in which oligomers, monomers, and fragmented products were included. Present study suggests that these polymers are involved in the formation of crosslinked networks of the films and the particles via surface reactions, where the crosslinking is enhanced by the ion bombardment.

  8. Assembly and Structure of alpha-helical Peptide Films on Hydrophobic Fluorocarbon Surfaces

    SciTech Connect

    Weidner, T.; Samual, N; McCrea, K; Gamble, L; Ward, R; Castner, D

    2010-01-01

    The structure, orientation, and formation of amphiphilic {alpha}-helix model peptide films on fluorocarbon surfaces has been monitored with sum frequency generation (SFG) vibrational spectroscopy, near-edge x-ray absorption fine structure (NEXAFS) spectroscopy, and x-ray photoelectron spectroscopy (XPS). The {alpha}-helix peptide is a 14-mer of hydrophilic lysine and hydrophobic leucine residues with a hydrophobic periodicity of 3.5. This periodicity yields a rigid amphiphilic peptide with leucine and lysine side chains located on opposite sides. XPS composition analysis confirms the formation of a peptide film that covers about 75% of the surface. NEXAFS data are consistent with chemically intact adsorption of the peptides. A weak linear dichroism of the amide {pi}* is likely due to the broad distribution of amide bond orientations inherent to the {alpha}-helical secondary structure. SFG spectra exhibit strong peaks near 2865 and 2935 cm{sup -1} related to aligned leucine side chains interacting with the hydrophobic surface. Water modes near 3200 and 3400 cm{sup -1} indicate ordering of water molecules in the adsorbed-peptide fluorocarbon surface interfacial region. Amide I peaks observed near 1655 cm{sup -1} confirm that the secondary structure is preserved in the adsorbed peptide. A kinetic study of the film formation process using XPS and SFG showed rapid adsorption of the peptides followed by a longer assembly process. Peptide SFG spectra taken at the air-buffer interface showed features related to well-ordered peptide films. Moving samples through the buffer surface led to the transfer of ordered peptide films onto the substrates.

  9. Polymer radiation curing: Epoxies, phenolics, fluorocarbons, and silicones. (Latest citations from the NTIS data base). Published Search

    SciTech Connect

    Not Available

    1992-09-01

    The bibliography contains citations concerning the processes and effects of radiation curing on epoxy resins, phenolics, fluorocarbons, and silicones. Gamma, ultraviolet, and infrared radiation are emphasized; however, polymer crosslinking by such electromagnetic wave radiation as microwave, laser, vacuum irradiation, and ionization is included. The citations also discuss the influence of radiation induced polymer curing on mechanical, electrical, and chemical properties of the polymers. (Contains a minimum of 235 citations and includes a subject term index and title list.)

  10. Biofabrication Under Fluorocarbon: A Novel Freeform Fabrication Technique to Generate High Aspect Ratio Tissue-Engineered Constructs

    PubMed Central

    Blaeser, Andreas; Duarte Campos, Daniela F.; Weber, Michael; Neuss, Sabine; Theek, Benjamin; Fischer, Horst

    2013-01-01

    Abstract Bioprinting is a recent development in tissue engineering, which applies rapid prototyping techniques to generate complex living tissues. Typically, cell-containing hydrogels are dispensed layer-by-layer according to a computer-generated three-dimensional model. The lack of mechanical stability of printed hydrogels hinders the fabrication of high aspect ratio constructs. Here we present submerged bioprinting, a novel technique for freeform fabrication of hydrogels in liquid fluorocarbon. The high buoyant density of fluorocarbons supports soft hydrogels by floating. Hydrogel constructs of up to 30-mm height were generated. Using 3% (w/v) agarose as the hydrogel and disposable syringe needles as nozzles, the printer produced features down to 570-?m diameter with a lateral dispensing accuracy of 89??m. We printed thin-walled hydrogel cylinders measuring 4.8?mm in height, with an inner diameter of ?2.9?mm and a minimal wall thickness of ?650??m. The technique was successfully applied in printing a model of an arterial bifurcation. We extruded under fluorocarbon, cellularized alginate tubes with 5-mm outer diameter and 3-cm length. Cells grew vigorously and formed clonal colonies within the 7-day culture period. Submerged bioprinting thus seems particularly suited to fabricate hollow structures with a high aspect ratio like vascular grafts for cardiovascular tissue engineering as well as branching or cantilever-like structures, obviating the need for a solid support beneath the overhanging protrusions. PMID:24083093

  11. Biofabrication under fluorocarbon: a novel freeform fabrication technique to generate high aspect ratio tissue-engineered constructs.

    PubMed

    Blaeser, Andreas; Duarte Campos, Daniela F; Weber, Michael; Neuss, Sabine; Theek, Benjamin; Fischer, Horst; Jahnen-Dechent, Willi

    2013-10-01

    Bioprinting is a recent development in tissue engineering, which applies rapid prototyping techniques to generate complex living tissues. Typically, cell-containing hydrogels are dispensed layer-by-layer according to a computer-generated three-dimensional model. The lack of mechanical stability of printed hydrogels hinders the fabrication of high aspect ratio constructs. Here we present submerged bioprinting, a novel technique for freeform fabrication of hydrogels in liquid fluorocarbon. The high buoyant density of fluorocarbons supports soft hydrogels by floating. Hydrogel constructs of up to 30-mm height were generated. Using 3% (w/v) agarose as the hydrogel and disposable syringe needles as nozzles, the printer produced features down to 570-?m diameter with a lateral dispensing accuracy of 89??m. We printed thin-walled hydrogel cylinders measuring 4.8?mm in height, with an inner diameter of ?2.9?mm and a minimal wall thickness of ?650??m. The technique was successfully applied in printing a model of an arterial bifurcation. We extruded under fluorocarbon, cellularized alginate tubes with 5-mm outer diameter and 3-cm length. Cells grew vigorously and formed clonal colonies within the 7-day culture period. Submerged bioprinting thus seems particularly suited to fabricate hollow structures with a high aspect ratio like vascular grafts for cardiovascular tissue engineering as well as branching or cantilever-like structures, obviating the need for a solid support beneath the overhanging protrusions. PMID:24083093

  12. Exchange transfusion with fluorocarbon for studying synaptically evoked optical signal in rat cortex.

    PubMed

    Nomura, Y; Fujii, F; Sato, C; Nemoto, M; Tamura, M

    2000-02-01

    Optical imaging of intrinsic signal is a powerful technique for studying the functional organization of the brain [T. Bonhoeffer, D. S. Kim, D. Malonek, D. Shoham, A. Grinvald, Optical imaging of the layout of functional domains in area 17 and across the area 17/18 border in cat visual cortex, Eur. J. Neurosci. 7 (1995) 1973-1988; M. Hubener, D. Shoham, A. Grinvald, T. Bonhoeffer, Spatial relationships among three columnar systems in cat area 17, J. Neurosci. 17 (1997) 9270-9284; D. Malonek, A. Grinvald, Interactions between electrical activity and cortical microcirculation revealed by imaging spectroscopy: implications for functional brain mapping, Science 272 (1996) 551-554; A. Shmuel, A. Grinvald, Functional organization for direction of motion and its relationship to orientation maps in cat area 18, J. Neurosci. 16 (1996) 6945-6964] [1] [10] [14] [22]. Three components of intrinsic optical signal can be distinguished. Two of these components can be attributed either to changes in blood volume or to changes in oxygen consumption [R.D. Frostig, E.E. Lieke, D.Y. Ts'o, A. Grinvald, Cortical functional architecture and local coupling between neuronal activity and the microcirculation revealed by in vivo high resolution optical imaging of intrinsic signals, Proc. Natl. Acad. Sci. U. S. A. 87 (1990) 6082-6086] [7]. The origin of the third component is not yet clear but the component seems to be based on scattered light [H.U. Dodt, G. D'Arcangelo, E. Pestel, W. Zieglgansberger, The spread of excitation in neocortical columns visualized with infrared-dark field videomicroscopy, NeuroReport 7 (1996) 1553-1558; K. Holthoff, O.W. Witte, Intrinsic optical signals in rat neocortical slices measured with near-infrared dark-field microscopy reveal changes in extracellular space, J. Neurosci. 16 (1996) 2740-2749; B.A. MacVicar, D. Hochman, Imaging of synaptically evoked intrinsic optical signals in hippocampal slices, J. Neurosci. 11 (1991) 1458-1469; L. Trachsel, H.U. Dodt, W. Zieglgansberger, The intrinsic optical signal evoked by chiasm stimulation in the rat suprachiasmatic nuclei exhibits GABAergic day-night variation, Eur. J. Neurosci. 8 (1996) 319-328] [3] [9] [13] [24]. A spectral fitting method with three components is used for the analysis of intrinsic optical signal [M. Nemoto, Y. Nomura, C. Sato, M. Tamura, K. Houkin, I. Koyanagi, H. Abe, Analysis of optical signals evoked by peripheral nerve stimulation in rat somatosensory cortex: dynamic changes in hemoglobin concentration and oxygenation, J. Cereb. Blood Flow Metab. 19 (1999) 246-259] [17]. In order to validate the analysis, we need the knowledge on contribution of signal resulted from hemoglobin to total intrinsic optical signal. The exchange transfusion with fluorocarbon has the advantage that can change the spectral contribution of hemoglobin [M. Ferrari, M.A. Williams, D.A. Wilson, N.V. Thakor, R.J. Traystman, D.F. Hanley, Cat brain cytochrome-c oxidase redox changes induced by hypoxia after blood-fluorocarbon exchange transfusion, Am. J. Physiol. 269 (1995) H417-H424; A.L. Sylvia, C.A. Piantadosi, O(2) dependence of in vivo brain cytochrome redox responses and energy metabolism in bloodless rats, J. Cereb. Blood Flow Metab. 8 (1988) 163-172] [6] [23]. Here we describe a new method of the reduction of hemoglobin signal from somatosensory evoked optical intrinsic signal in rat cortex by the combination of exchange transfusion with fluorocarbon and imaging system of thinned skull cranial window. The method allows for the study of the synaptically evoked changes in light scattering as well as fluorescence of calcium indicator or voltage-sensitive dye without absorption of hemoglobin. PMID:10719260

  13. Biocolonizable keratoprosthesis with a microporous fluorocarbon skirt: a two-year study

    NASA Astrophysics Data System (ADS)

    Legeais, Jean-Marc; Renard, Gilles; Parel, Jean-Marie A.; Savoldelli, Michele; Pouliquen, Yves

    1994-06-01

    Most complications of keratoprosthesis (KPro) occur at the tissue-to-implant interface. The ideal prosthesis would eliminate this interface by having the tissue actually grown into the support material forming the haptic. We present a 2-year clinical human study of a novel biocolonizable KPro on 24 eyes of 24 patients. To promote tissue stability, a 9 mm (Phi) skirt made of a new microporous fluorocarbon was used. The optical core or the KPro optic was made of a medical grade polymethylmetacrylate (PMMA) commonly used world-wide to fabricate intraocular lenses. The optic was 5 mm in diameter and 2.67 mm long. The average follow-up was 14 months. Mean corrected visual acuity was 20/100. Anatomic failures occurred in 5 cases in the first year (1 lens dislocation, 1 endophthalmitis, 3 extrusions). These preliminary results appear encouraging. However, we did not eliminate all the complications with this biocompatible inert microporous polymer. Intensive research in mechanical, chemical, and surface biocompatibility is required to develop a true artificial cornea.

  14. Selective adsorption of fluorocarbons and its effects on the adhesion of plasma polymer protective coatings

    NASA Astrophysics Data System (ADS)

    Moffitt, C. E.; Reddy, C. M.; Yu, Q. S.; Wieliczka, D. M.; Yasuda, H. K.

    2000-07-01

    Cathodic DC plasma deposited films have shown promise as intermediate adhesion and barrier layers for use in the interface engineering of corrosion protection systems on various materials. The surface treatment of plasma deposited trimethylsilane (TMS) films with various post-deposition plasma treatments can improve the adhesion of various paints to these films, which are usually strongly adhered to underlying substrates. Research into the application of these systems for corrosion protection of aluminum alloys included post-deposition treatments of the TMS films with hexafluoroethane (HFE) plasmas, which was seen to significantly improve the adhesion of primers. Oxygen plasma cleaning of the alloy surfaces, prior to deposition of the TMS film, is normally employed to remove organic contaminants. During testing of sample aluminum panels, one batch was processed without the oxygen plasma treatment and exhibited extensive adhesion failures. The investigation of these results shows that low levels of fluorocarbon contaminants readily react with the alloy surface and deposit a fluorine containing carbonaceous layer, which dramatically interferes with the adhesion of the plasma polymer to the alloys, but the adhesion with primer coatings remains tenacious. X-ray photoelectron spectroscopy (XPS) studies also show that the presence of even low levels of these contaminants in the chamber, during the oxygen cleaning process, is sufficient to induce the conversion of the surface from oxide to a mixture of oxide and fluoride. This conversion is considered detrimental to the corrosion resistance of these systems.

  15. Thermally robust and porous noncovalent organic framework with high affinity for fluorocarbons and CFCs

    NASA Astrophysics Data System (ADS)

    Chen, Teng-Hao; Popov, Ilya; Kaveevivitchai, Watchareeya; Chuang, Yu-Chun; Chen, Yu-Sheng; Daugulis, Olafs; Jacobson, Allan J.; Miljani?, Ognjen .

    2014-10-01

    Metal-organic and covalent organic frameworks are porous materials characterized by outstanding thermal stability, high porosities and modular synthesis. Their repeating structures offer a great degree of control over pore sizes, dimensions and surface properties. Similarly precise engineering at the nanoscale is difficult to achieve with discrete molecules, since they rarely crystallize as porous structures. Here we report a small organic molecule that organizes into a noncovalent organic framework with large empty pores. This structure is held together by a combination of [N-HN] hydrogen bonds between the terminal pyrazole rings and [??] stacking between the electron-rich pyrazoles and electron-poor tetrafluorobenzenes. Such a synergistic arrangement makes this structure stable to at least 250?C and porous, with an accessible surface area of 1,159?m2?g-1. Crystals of this framework adsorb hydrocarbons, CFCs and fluorocarbonsthe latter two being ozone-depleting substances and potent greenhouse specieswith weight capacities of up to 75%.

  16. Thermally robust and porous noncovalent organic framework with high affinity for fluorocarbons and CFCs.

    PubMed

    Chen, Teng-Hao; Popov, Ilya; Kaveevivitchai, Watchareeya; Chuang, Yu-Chun; Chen, Yu-Sheng; Daugulis, Olafs; Jacobson, Allan J; Miljani?, Ognjen

    2014-01-01

    Metal-organic and covalent organic frameworks are porous materials characterized by outstanding thermal stability, high porosities and modular synthesis. Their repeating structures offer a great degree of control over pore sizes, dimensions and surface properties. Similarly precise engineering at the nanoscale is difficult to achieve with discrete molecules, since they rarely crystallize as porous structures. Here we report a small organic molecule that organizes into a noncovalent organic framework with large empty pores. This structure is held together by a combination of [N-HN] hydrogen bonds between the terminal pyrazole rings and [??] stacking between the electron-rich pyrazoles and electron-poor tetrafluorobenzenes. Such a synergistic arrangement makes this structure stable to at least 250?C and porous, with an accessible surface area of 1,159?m(2)?g(-1). Crystals of this framework adsorb hydrocarbons, CFCs and fluorocarbons-the latter two being ozone-depleting substances and potent greenhouse species-with weight capacities of up to 75%. PMID:25307413

  17. Effect of nonsinusoidal bias waveforms on ion energy distributions and fluorocarbon plasma etch selectivity

    SciTech Connect

    Agarwal, Ankur; Kushner, Mark J.

    2005-09-15

    The distributions of ion energies incident on the wafer significantly influence feature profiles and selectivity during plasma etching. Control of ion energies is typically obtained by varying the amplitude or frequency of a radio frequency sinusoidal bias voltage applied to the substrate. The resulting ion energy distribution (IED), though, is generally broad. Controlling the width and shape of the IED can potentially improve etch selectivity by distinguishing between threshold energies of surface processes. In this article, control of the IED was computationally investigated by applying a tailored, nonsinusoidal bias waveform to the substrate of an inductively coupled plasma. The waveform we investigated, a quasi-dc negative bias having a short positive pulse each cycle, produced a narrow IED whose width was controllable based on the length of the positive spike and frequency. We found that the selectivity between etching Si and SiO{sub 2} in fluorocarbon plasmas could be controlled by adjusting the width and energy of the IED. Control of the energy of a narrow IED enables etching recipes that transition between speed and selectivity without change of gas mixture.

  18. Electrowetting on plasma-deposited fluorocarbon hydrophobic films for biofluid transport in microfluidics

    NASA Astrophysics Data System (ADS)

    Bayiati, P.; Tserepi, A.; Petrou, P. S.; Kakabakos, S. E.; Misiakos, K.; Gogolides, E.

    2007-05-01

    The present work focuses on the plasma deposition of fluorocarbon (FC) films on surfaces and the electrostatic control of their wettability (electrowetting). Such films can be employed for actuation of fluid transport in microfluidic devices, when deposited over patterned electrodes. Here, the deposition was performed using C4F8 and the plasma parameters that permit the creation of films with optimized properties desirable for electrowetting were established. The wettability of the plasma-deposited surfaces was characterized by means of contact angle measurements (in the static and dynamic mode). The thickness of the deposited films was probed in situ by means of spectroscopic ellipsometry, while the surface roughness was provided by atomic force microscopy. These plasma-deposited FC films in combination with silicon nitride, a material of high dielectric constant, were used to create a dielectric structure that requires reduced voltages for successful electrowetting. Electrowetting experiments using protein solutions were conducted on such optimized dielectric structures and were compared with similar structures bearing commercial spin-coated Teflon amorphous fluoropolymer (AF) film as the hydrophobic top layer. Our results show that plasma-deposited FC films have desirable electrowetting behavior and minimal protein adsorption, a requirement for successful transport of biological solutions in "digital" microfluidics.

  19. Surface-Morphology-Induced Hydrophobicity of Fluorocarbon Films Grown by a Simultaneous Etching and Deposition Process

    NASA Astrophysics Data System (ADS)

    Fang, J. S.; Lin, C. S.; Huang, Y. Y.; Chin, T. S.

    2015-08-01

    Development of facile methods to prepare hydrophobic films is of great important. We report fluorocarbon films deposited by a simple plasma-assisted chemical vapor deposition method using C3F8 and C2H2 with extra Ar and/or O2 gases. The surface characteristics of the films were examined by scanning electron microscopy, atomic force microscopy, and x-ray photoelectron spectroscopy. The hydrophobic and oleophobic properties of the films were evaluated by measurements of static contact angle. The results showed that the film deposited with C3F8, C2H2, Ar, and O2 exhibited a water contact angle of 114, hexadecane contact angle of 45, and transmittance of 94.5%. Photoelectron spectra further revealed that the films contained mainly CF and CF2 bonds and thus a high F/C ratio. Introduction of O2 increased the F/C ratio, which combined with the stripe-like surface of the films achieved better hydrophobicity.

  20. Comprehensive testing to measure the response of fluorocarbon rubber (FKM) to Hanford tank waste simulant

    SciTech Connect

    NIGREY,PAUL J.; BOLTON,DENNIS L.

    2000-02-01

    This report presents the findings of the Chemical Compatibility Program developed to evaluate plastic packaging components that may be incorporated in packaging mixed-waste forms for transportation. Consistent with the methodology outlined in this report, the authors performed the second phase of this experimental program to determine the effects of simulant Hanford tank mixed wastes on packaging seal materials. That effort involved the comprehensive testing of five plastic liner materials in an aqueous mixed-waste simulant. The testing protocol involved exposing the materials to {approximately}143, 286, 571, and 3,670 Krad of gamma radiation and was followed by 7-, 14-, 28-, 180-day exposures to the waste simulant at 18, 50, and 60 C. Fluorocarbon (FKM) rubber samples subjected to the same protocol were then evaluated by measuring seven material properties: specific gravity, dimensional changes, mass changes, hardness, compression set, vapor transport rates, and tensile properties. From the analyses, they determined that FKM rubber is not a good seal material to withstand aqueous mixed wastes having similar composition to the one used in this study. They have determined that FKM rubber has limited chemical durability after exposure to gamma radiation followed by exposure to the Hanford tank simulant mixed waste at elevated temperatures above 18 C.

  1. Evaluation of the acute cardiac and central nervous system effects of the fluorocarbon trifluoromethane in baboons

    SciTech Connect

    Branch, C.A.; Goldberg, D.A.; Ewing, J.R.; Butt, S.S.; Gayner, J.; Fagan, S.C.

    1994-12-31

    The gaseous fluorocarbon trifluoromethane has recently been investigated for its potential as an in vivo gaseous indicator for nuclear magnetic resonance studies of brain perfusion. Trifluoromethane may also have significant value as a replacement for chlorofluorocarbon fire retardants. Because of possible species-specific cardiotoxic and anesthetic properties, the toxicological evaluation of trifluoromethane in primates (Papio anubis) is necessary prior to its evaluation in humans. We report the acute cardiac and central nervous system effects of trifluoromethane in eight anesthetized baboons. A dose-response effect was established for respiratory rate, electroencephalogram, and cardiac sinus rate, which exhibited a stepwise decrease from 10% trifluoromethane. No spontaneous arrhythmias were noted, and arterial blood pressure remained unchanged at any inspired level. Intravenous epinephrine infusions (1 {mu}g/kg) induced transient cardiac arrhythmia in 1 animal only at 70% FC-23 (v/v) trifluoromethane. Trifluoromethane appears to induce mild dose-related physiological changes at inspired levels of 30% or more, indicative of an anesthetic effect. These data suggest that trifluoromethane may be safe to use in humans, without significant adverse acute effects, at an inspired level of 30%. 23 refs., 3 figs., 3 tabs.

  2. Comparative study of plasma-deposited fluorocarbon coatings on different substrates

    NASA Astrophysics Data System (ADS)

    Farsari, E.; Kostopoulou, M.; Amanatides, E.; Mataras, D.; Rapakoulias, D. E.

    2011-05-01

    The deposition of hydrophobic fluorocarbon coatings from C2F6 and C2F6-H2 rf discharges on different substrates was examined. Polyester textile, glass and two different ceramic compounds were used as substrates. The effect of the total gas pressure, the rf power dissipation and the deposition time on the hydrophobic character of the samples was investigated. Films deposited on polyester textiles at low pressure (0.03 mbar) and power consumption (16 mW cm-2) using pure C2F6 presented the highest water contact angles (~150). On the other hand, the addition of hydrogen was necessary in order to deposit stable hydrophobic coatings on glass and ceramic substrates. Coatings deposited on glass at intermediate deposition rates (~100 min-1) and pressures presented the highest angles (~105). Concerning the heavy clay ceramics, samples treated in low-pressure (0.05 mbar) and low-power (16 mW cm-2) discharges showed the highest contact angles. The deposition time was found to play an important role in the hydrophobicity and long-term behaviour of porous and rough substrates.

  3. Global warming implications of non-fluorocarbon technologies as CFC replacements

    SciTech Connect

    Fischer, S.K.; Tomlinson, J.J.

    1993-12-31

    Many technologies could be developed for use in place of conventional compression systems for refrigeration and air conditioning. Comparisons of the global warming impacts using TEWI (Total Equivalent Warming Impact) can be used to identify alternatives that have the potential for lower environmental impacts than electric-driven vapor compression systems using HCFCs and HFCs. Some options, such as secondary heat transfer loops in commercial refrigeration systems to reduce refrigerant charge and emission rates, could be useful in reducing the losses of refrigerants to the atmosphere. Use of ammonia instead of a fluorocarbon in a system with a secondary loop offers only a small potential for decreasing TEWI, and this may not warrant the increased complexity and risks of using ammonia in a retail sales environment. A few technologies, such as adsorption heat pumps, have efficiency levels that show reduced TEWI levels compared to conventional and state of the art compression systems, and further development could lead to an even more favorable comparison. Health and safety risks of the alternative technologies and the materials they employ must also be considered.

  4. Aggregation behavior of fluorocarbon and hydrocarbon cationic surfactant mixtures: a study of 1H NMR and 19F NMR.

    PubMed

    Dong, Shuli; Xu, Guiying; Hoffmann, Heinz

    2008-08-01

    The aggregation behavior and the interaction of four mixed systems for a cationic fluorocarbon surfactant, diethanolheptadecafluoro-2-undecanolmethylammonium chloride (DEFUMACl), mixing with cationic hydrocarbon surfactants, alkyltrimethylammonium chloride, CnTACl (n=12, 14, 16, and 18; where n=12 is DTACl, n=14 is TTACl, n=16 is CTACl, and n=18 is OTACl), were studied by 1H and 19F NMR in more detail. The results of 19F NMR measurements strongly indicate that in the three mixed systems of DEFUMACl/DTACl, DEFUMACl/TTACl, and DEFUMACl/CTACl at different molar fractions of fluorocarbon surfactant (alphaF=(cDEFUMACl/cDEFUMACl+cCnTACl)), with an increase of the total concentration of fluorocarbon and hydrocarbon surfactants (cT=cF+cH), the mixed micelles at the first break point and the individual DEFUMACl micelles at the second break point form. However, three different types of micelles were determined in DEFUMACl/OTACl mixtures by 19F NMR measurements, OTACl-rich and DEFUMACl-rich mixed micelles and individual DEFUMACl micelles, respectively. The chemical shifts of proton Deltadelta (1H) for -CH3 in the mixed systems of DEFUMACl/CnTACl (n=12, 14, 16, and 18) have different variation trends from the 19F NMR measurements. For the two systems of DEFUACl/DTACl and DEFUMACl/TTACl, the mixed micelles form at the first break point. At the second break point, for lower alpha F values the DTACl-rich and TTACl-rich mixed micelles form with a strong downfield shift and for higher alpha F values DEFUMACl-rich mixed micelles form with a strong upfield. For the other two systems of DEFUMACl/CTACl and DEFUMAC/OTACl, the chemical shifts of proton Deltadelta (1H) of -CH3 increase with an increase of the total concentration of DEFUMACl/CTACl or OTACl, and mixed CH- and CF-surfactant micelles form. At higher total concentration, the greater effect of fluorinated chains of DEFUMACl on CH-chains was obvious, resulting in the strong upfield chemical shifts. In cationic fluorocarbon and hydrocarbon surfactant mixtures, the different kinds of micelles observed by 19F and 1H NMR measurements could be caused by the increase in alkyl chain length of hydrocarbon surfactants with different critical micelle concentrations. Combining two theoretical models for mixing, for the four different chain-length hydrocarbon surfactants studied, one can conclude that the two components of mixtures interact with each other and form mixed micelles in two completely different ways according to their molecular properties and cmc values in a certain range of total concentrations. One is close to an ideal mixing case with the formation of one type of mixed micelles, such as the DEFUMACl/DTACl and DEFUMACl/TTACl systems. The other is a demixing case with the formation of two types of micelles, i.e., fluorocarbon-rich and hydrocarbon-rich mixed micelles, such as DEFUMACl/CTACl and DEFUMACl/OTACl systems. However, as the total concentrations of the mixed systems are high enough, the four systems tend to demix and to form individual micelles of corresponding components due to the initial respective interaction between fluorocarbon and hydrocarbon chains. That is to say, at high total concentration, the individual DEFUMACl micelles in all four systems could form. These results may be primarily directed toward acquiring an understanding of the mechanism of CF-CH mixtures in aqueous solution and secondarily directed toward providing more detailed information on nonideal mixing. PMID:18613719

  5. UV-assisted modification and removal mechanism of a fluorocarbon polymer film on low-k dielectric trench structure.

    PubMed

    Mukherjee, Tamal; Berhe, Seare A; Goswami, Arindom; Chyan, Oliver; Singh, Kanwal Jit; Brown, Ian

    2015-03-11

    In this study, we report the first chemical characterization of a plasma-deposited model fluoropolymer on low-k dielectric nanostructure and its decomposition in UV/O2 conditions. Carbonyl incorporation and progressive removal of fluorocarbon fragments from the polymer were observed with increasing UV (?230 nm) irradiation under atmospheric conditions. A significant material loss was achieved after 300 s of UV treatment and a subsequent wet clean completely removed the initially insoluble fluoropolymer from the patterned nanostructures. A synergistic mechanism of UV light absorption by carbonyl chromophore and oxygen incorporation is proposed to account for the observed photodegradation of the fluoropolymer. PMID:25679964

  6. Gain and loss mechanisms for neutral species in low pressure fluorocarbon plasmas by infrared spectroscopy

    SciTech Connect

    Nelson, Caleb T.; Overzet, Lawrence J.; Goeckner, Matthew J.

    2012-09-15

    This article examines the chemical reaction pathways of stable neutral species in fluorocarbon plasmas. Octafluorocyclobutane (c-C{sub 4}F{sub 8}) inductively coupled plasma discharges were found to primarily produce stable and metastable products downstream from the discharge, including c-C{sub 4}F{sub 8}, C{sub 2}F{sub 4}, C{sub 2}F{sub 6}, CF{sub 4}, C{sub 3}F{sub 8}, C{sub 4}F{sub 10}, C{sub 3}F{sub 6}, and CF{sub 2}. A novel analysis technique allows the estimation of gain and loss rates for neutral species in the steady state as functions of residence time, pressure, and discharge power. The gain and loss rates show that CF{sub 4}, C{sub 2}F{sub 6}, C{sub 3}F{sub 8}, and C{sub 4}F{sub 10} share related gain mechanisms, speculated to occur at the surface. Further analysis confirms that CF{sub 2} is predominantly produced at the chamber walls through electron impact dissociation of C{sub 2}F{sub 4} and lost through gas-phase addition reactions to form C{sub 2}F{sub 4}. Additionally, time-resolved FTIR spectra provide a second-order rate coefficient of 1.8 Multiplication-Sign 10{sup -14} cm{sup 3}/s for the gas-phase addition of CF{sub 2} to form C{sub 2}F{sub 4}. Finally, C{sub 2}F{sub 4,} which is much more abundant than CF{sub 2} in the discharge, is shown to be dominantly produced through electron impact dissociation of c-C{sub 4}F{sub 8} and lost through either surface or gas-phase addition reactions.

  7. Fluorocarbon materials produced by the thermo destruction of polytetrafluoroethylene and possibility of theirs application in Li/(CFx)n batteries

    NASA Astrophysics Data System (ADS)

    Gnedenkov, S. V.; Tsvetnikov, A. K.; Opra, D. P.; Sinebryukhov, S. L.; Sergienko, V. I.

    A few fluorocarbon compounds (CFx)n were produced by the original thermo-gas-dynamic destruction (TD) of polytetrafluoroethylene (PTFE) at the high temperatures 530 and 550 C. The chemical composition, electrochemical and morphological properties of such materials were characterized by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM)/X-ray energy dispersive spectroscopy (XEDS) and compared to commercial fluorinated petroleum coke (CF1)n. The possibility of the application of the new obtained compounds as the cathode materials in primary lithium batteries was estimated. The differences of the investigated samples properties, which observed during electrochemical tests, are discussed.

  8. Feature Profile Evolution of SiO2 Trenches In Fluorocarbon Plasmas

    NASA Technical Reports Server (NTRS)

    Hwang, Helen; Govindan, T. R.; Meyyappan, M.; Arunachalam, Valli; Rauf, Shahid; Coronell, Dan; Carroll, Carol W. (Technical Monitor)

    1999-01-01

    Etching of silicon microstructures for semiconductor manufacturing in chlorine plasmas has been well characterized. The etching proceeds in a two-part process, where the chlorine neutrals passivate the Si surface and then the ions etch away SiClx. However, etching in more complicated gas mixtures and materials, such as etching of SiO2 in Ar/C4F8, requires knowledge of the ion and neutral distribution functions as a function of angle and velocity, in addition to modeling the gas surface reactions. In order to address these needs, we have developed and integrated a suite of models to simulate the etching process from the plasma reactor level to the feature profile evolution level. This arrangement allows for a better understanding, control, and prediction of the influence of equipment level process parameters on feature profile evolution. We are currently using the HPEM (Hybrid Plasma Equipment Model) and PCMCM (Plasma Chemistry Monte Carlo Model) to generate plasma properties and ion and neutral distribution functions for argon/fluorocarbon discharges in a GEC Reference Cell. These quantities are then input to the feature scale model, Simulation of Profile Evolution by Level Sets (SPELS). A surface chemistry model is used to determine the interaction of the incoming species with the substrate material and simulate the evolution of the trench profile. The impact of change of gas pressure and inductive power on the relative flux of CFx and F to the wafer, the etch and polymerization rates, and feature profiles will be examined. Comparisons to experimental profiles will also be presented.

  9. Composite fluorocarbon membranes by surface-initiated polymerization from nanoporous gold-coated alumina.

    PubMed

    Escobar, Carlos A; Zulkifli, Ahmad R; Faulkner, Christopher J; Trzeciak, Alex; Jennings, G Kane

    2012-02-01

    This manuscript describes the versatile fabrication and characterization of a novel composite membrane that consists of a porous alumina support, a 100 nm thick nanoporous gold coating, and a selective poly(5-(perfluorohexyl)norbornene) (pNBF6) polymer that can be grown exclusively from the nanoporous gold or throughout the membrane. Integration of the three materials is achieved by means of silane and thiol chemistry, and the use of surface-initiated ring-opening metathesis polymerization (SI-ROMP) to grow the pNBF6. The use of SI-ROMP allows tailoring of the extent of polymerization of pNBF6 throughout the structure by varying polymerization time. Scanning electron microscopy (SEM) images indicate that the thin polymer films cover the structure entirely. Cross-sectional SEM images of the membrane not only corroborate growth of the pNBF6 polymer within both the porous alumina and the nanoporous gold coating but also show the growth of a pNBF6 layer between these porous substrates that lifts the nanoporous gold coating away from the alumina. Advancing contact angle (?(A)) measurements show that the surfaces of these composite membranes exhibit both hydrophobic (?(A) = 121-129) and oleophobic (?(A) = 69-74) behavior due to the fluorocarbon side chains of the pNBF6 polymer that dominate the surface. Results from electrochemical impedance spectroscopy (EIS) confirm that the membranes provide effective barriers to aqueous ions, as evidenced by a resistive impedance on the order of 1 10(7) ? cm(2). Sulfonation of the polymer backbone substantially enhances ion transport through the composite membrane, as indicated by a 40-60 fold reduction in resistive impedance. Ion transport and selectivity of the membrane change by regulating the polymerization time. The fluorinated nature of the sulfonated polymer renders the membrane selective toward molecules with similar chemical characteristics. PMID:22195729

  10. Atmospheric degradation mechanisms of hydrogen containing chlorofluorocarbons (HCFC) and fluorocarbons (HFC)

    NASA Technical Reports Server (NTRS)

    Zellner, Reinhard

    1990-01-01

    The current knowledge of atmospheric degradation of hydrogen containing chlorofluorocarbons (HCFC 22 (CHClF2), HCFC 123 (CHCl2CF3), HCFC 124 (CHClFCF3), HCFC 141b (CFCl2CH3), HCFC 142b (CF2ClCH3)) and fluorocarbons (HFC 125 (CHF2CF3), HFC 134a (CH2FCF3), HFC 152a (CHF2CH3)) is assessed. Except for the initiation reaction by OH radicals, there are virtually no experimental data available concerning the subsequent oxidative breakdown of these molecules. However, from an analogy to the degradation mechanisms of simple alkanes, some useful guidelines as to the expected intermediates and final products can be derived. A noteable exception from this analogy, however, appears for the oxi-radicals. Here, halogen substitution induces new reaction types (C-Cl and C-C bond ruptures) which are unknown to the unsubstituted analogues and which modify the nature of the expected carbonyl products. Based on an evaluation of these processes using estimated bond strength data, the following simplified rules with regards to the chlorine content of the HCFC's may be deduced: (1) HCFC's containing one chlorine atom such as 22 and 142b seem to release their chlorine content essentially instantaneous with the initial attack on the parent by OH radicals, and for HCFC 124, such release is apparently prevented; (2) HCFC's such as 123 and 141b with two chlorine atoms are expected to release only one of these instantaneously; and the second chlorine atom may be stored in potentially long-lived carbonyl compounds such as CF3CClO or CClFO.

  11. ToF SIMS analysis of a fluorocarbon-grafted PET with a gold cluster ion source

    NASA Astrophysics Data System (ADS)

    Zhu, Zhengmao; Kelley, Michael J.

    2006-07-01

    Cluster ions have been recognized as a superb primary species in time of flight secondary ion mass spectroscopy (ToF-SIMS) compared with monatomic primary ions, as they significantly enhance the secondary ion yields from bulk samples. Self-assembled monolayers provide an important system for studying the fundamental mechanism involved in the yield enhancement. We used a gold cluster ion source to analyze a new type of self-assembled monolayer: a fluorocarbon-grafted polyethylene terephthalate. In addition to the structure details, which helped to understand the grafting mechanism, ToF-SIMS analysis revealed that fluorocarbon secondary ion yield enhancements by cluster ions were due to the enhanced sputter efficiency. A larger information depth may also be expected from the enhancement. Both mathematical definitions of damage cross-section and disappearance cross-section were revisited under a new context. Another cross-section parameter, sputter cross-section, was introduced to differentiate the beam induced sputter process from damage process.

  12. A cationic fluorocarbon surfactant DEFUMACl and its mixed systems with cationic surfactants: 19F NMR and surface tension study.

    PubMed

    Dong, Shuli; Li, Xin; Xu, Guiying; Hoffmann, Heinz

    2007-05-31

    A cationic fluorocarbon surfactant system of diethanolheptadecafluoro-2-undecanolmethylammonium chloride (DEFUMACl) and both mixed systems of DEFUMACl/cationic dodecyltrimethylammonium chloride (DTACl) and DEFUMACl/cationic Gemini copolymer was investigated by 19F NMR spectroscopy and surface tension measurements. The critical micelle concentration (cmc) of DEFUMACl by 19F NMR is about 3.40 mmol/L, which is completely consistent with that obtained by the surface tension method. The studies of salt and temperature on the cmc values of DEFUMACl suggest that both salt addition and temperature increase decrease the cmc values of DEFUMACl. 19F NMR measurements provide much richer information on both mixed systems. For the DEFUMACl-DTACl system, two break points were observed with increased total surfactant concentration. The first break point means the DEFUMACl and DTACl mixed micelles and the second one implies the individual DEFUMACl micelles. Results of 19F NMR and surface tension measurements for DEFUMACl/cationic Gemini copolymer mixtures show three peculiar break points, corresponding to the critical association concentration (cac) of DEFUMACl, the concentration where cationic Gemini copolymer molecules become saturated by DEFUMACl micelles, and the concentration where DEFUMACl micelles and cationic Gemini copolymer coexist. These peculiar points in the cationic-fluorocarbon and cationic-copolymer systems were first reported by 19F NMR and surface tension measurements. These results should broaden the useful information for a better understanding of the mechanism of interaction and the behavior of surfactant-polymer mixtures. PMID:17477561

  13. 157 nm Pellicles (Thin Films) for Photolithography: Mechanistic Investigation of the VUV and UV-C Photolysis of Fluorocarbons

    SciTech Connect

    Lee, Kwangjoo; Jockusch, Steffen; Turro, Nicholas J.; French, Roger H.; Wheland, Robert C.; Lemon, M F.; Braun, Andre M.; Widerschpan, Tatjana; Dixon, David A.; Li, Jun; Ivan, Marius; Zimmerman, Paul

    2005-06-15

    The use of 157 nm as the next lower wavelength for photolithography for the production of semiconductors has created a need for transparent and radiation-durable polymers for use in soft pellicles, the polymer films which protect the chip from particle deposition. The most promising materials for pellicles are fluorinated polymers, but currently available fluorinated polymers undergo photodegradation and/or photodarkening upon long term exposure to 157 nm irradiation. To understand the mechanism of the photodegradation and photodarkening of fluorinated polymers, mechanistic studies on the photolysis of liquid model fluorocarbons, including perfluorobutylethyl ether and perfluoro-2 H-3-oxa-heptane, were performed employing UV, NMR, FTIR, GC, and GC/MS analyses. All hydrogen-containing compounds showed decreased photostability compared to the fully perfluorinated compounds. Irradiation in the presence of atmospheric oxygen showed reduced photostability compared to deoxygenated samples. Photolysis of the samples was performed at 157, 172, 185, and 254 nm and showed only minor wavelength dependence. Mechanisms for photodegradation of the fluorocarbons are proposed, which involve Rydberg excited states. Time-dependent density functional theory has been used to predict the excitation spectra of model compounds.

  14. Effect of Fluorocarbon and Hydrocarbon Chain Lengths in Hybrid Surfactants for Supercritical CO2.

    PubMed

    Sagisaka, Masanobu; Ono, Shinji; James, Craig; Yoshizawa, Atsushi; Mohamed, Azmi; Guittard, Frdric; Rogers, Sarah E; Heenan, Richard K; Yan, Ci; Eastoe, Julian

    2015-07-14

    Hybrid surfactants containing both fluorocarbon (FC) and hydrocarbon (HC) chains have recently been shown to solubilize water and form elongated reversed micelles in supercritical CO2. To clarify the most effective FC and HC chain lengths, the aggregation behavior and interfacial properties of hybrid surfactants FCm-HCn (FC length m/HC length n = 4/2, 4/4, 6/2, 6/4, 6/5, 6/6, and 6/8) were examined in W/CO2 mixtures as functions of pressure, temperature, and water-to-surfactant molar ratio (W0). The solubilizing power of hybrid surfactants for W/CO2 microemulsions was strongly affected by not only the FC length but also by that of the HC. Although the surfactants having short FC and/or HC tails (namely, m/n = 4/2, 4/4, and 6/2) did not dissolve in supercritical CO2 (even at ?17 mM, ?400 bar, temperature ? 75 C, and W0 = 0-40), the other hybrid surfactants were able to yield transparent single-phase W/CO2 mixtures identified as microemulsions. The solubilizing power of FC6-HCm surfactants reached a maximum (W0 ? 80 at 45 C and 350 bar) with a hydrocarbon length, m, of 4. The W0 value of 80 is the highest for a HC-FC hybrid surfactant, matching the highest value reported for a FC surfactant which contained more FC groups. High-pressure small-angle neutron scattering measurements from FCm-HCn/D2O/CO2 microemulsions were consistent with growth of the microemulsion droplets with increasing W0. In addition, not only spherical reversed micelles but also nonspherical assemblies (rodlike or ellipsoidal) were found for the systems with FC6-HCn (n = 4-6). At fixed surfactant concentration and W0 (17 mM and W0 = 20), the longest reversed micelles were obtained for FC6-HC6 where a mean aspect ratio of 6.3 was calculated for the aqueous cores. PMID:26080002

  15. X-ray photoelectron spectroscopic study of Ge2Sb2Te5 etched by fluorocarbon inductively coupled plasmas

    NASA Astrophysics Data System (ADS)

    Kang, S.-K.; Oh, J. S.; Park, B. J.; Kim, S. W.; Lim, J. T.; Yeom, G. Y.; Kang, C. J.; Min, G. J.

    2008-07-01

    X-ray photoelectron spectroscopy was used to determine the level of surface fluorination damage of Ge2Sb2Te5 (GST) etched by fluorocarbon gases at different F/C ratios. When blank GST was etched, the gas with a higher F/C ratio produced a thinner C-F polymer on the etched surface but fluorinated Ge, Sb, and Te compounds were observed in the remaining GST. When the sidewall of the etched GST features was investigated, a thicker fluorinated layer was observed on the GST sidewall etched by the higher F/C ratio gas, indicating more fluorination due to the difficulty in preventing F diffusion into the GST through the thinner C-F layer.

  16. Fluorocarbon chain end-capped poly(carbonate urethane)s as biomaterials: blood compatibility and chemical stability assessments.

    PubMed

    Xie, Xingyi; Wang, Ruifang; Li, Jiehua; Luo, Liang; Wen, Da; Zhong, Yinping; Zhao, Changsheng

    2009-04-01

    Previous work has shown the synthesis of fluorocarbon chain (CF(3)(CF(2))(6)CH(2)O-) end-capped poly(carbonate urethane)s (FPCUs) and confirmed the presence of a novel bilayered surface structure in FPCUs, that is, the top fluorocarbon and subsurface hard segment layers (Xie et al., J Biomed Mater Res Part A 2008; 84:30-43). In this work, the effects of such surface structure on blood compatibility were investigated using hemolytic test and platelet adhesion analysis. The chemical stability of the polymers was also determined by Zhao's glass wool-H(2)O(2)/CoCl(2) test and phosphate-buffered saline (PBS, pH = 3.1-3.3) treatment. One of the FPCUs, FPCU-A, and two control materials, a poly(ether urethane) (PEU) and a poly(carbonate urethane) (PCU), were investigated. No significant difference in hemolytic indices was observed among the three materials, whereas the adherent density and deformation of platelets were much lower on FPCU-A compared with on PCU and PEU. Severe surface cracking and surface buckling developed in prestressed PEU and PCU films after H(2)O(2)/CoCl(2) treatment, respectively, whereas smooth surface was observed for the FPCU-A. PBS incubation resulted in parallel ridge-like morphology in PCU whereas PEU and FPCU-A retained their smooth surfaces. Under relatively high stress conditions, all the materials developed well-oriented strip-like surface patterns. Results from ATR-FTIR spectra revealed a surface oxidation mechanism as described in literature. However, observations of universal decrease of molecular weights under stress conditions further suggested the presence of another bulk stress oxidation mechanism. Regardless the degradation mechanisms involved, the unique bilayered surface structure really improved the blood compatibility and chemical stability of FPCU-A, indicating that further in vivo investigations are worthwhile. PMID:18837450

  17. Selective etching of SiO[sub 2] over polycrystalline silicon using CHF[sub 3] in an inductively coupled plasma reactor. [SiO[sub 2]; Si; fluorocarbons

    SciTech Connect

    Rueger, N.R.; Doemling, M.F.; Schaepkens, M.; Beulens, J.J.; Standaert, T.E.; Oehrlein, G.S. )

    1999-09-01

    Selective etching of SiO[sub 2] over polycrystalline silicon has been studied using CHF[sub 3] in an inductively coupled plasma reactor (ICP). Inductive powers between 200 and 1400 W, as well as pressures of 6, 10, and 20 mTorr were used in this study of the etch rate and selectivity behaviors for silicon dioxide, silicon, and passively deposited fluorocarbon films. Using [ital in situ] ellipsometry, the etch rates for all three of these materials were obtained for a self-bias voltage of [minus]85 V, as well as passive deposition rates of fluorocarbon films. X-ray photoelectron spectroscopy has been used to examine the composition of steady-state fluorocarbon films present on the surfaces of polycrystalline silicon, and silicon dioxide during etching at high and low inductive powers. The dependence of the silicon etching behavior is shown to be clearly linked to the fluorocarbon polymerization and etching behavior. Thus, the polymerization and etching behavior of the fluorocarbon is the overwhelming parameter that governs the etch selectivity process within the ICP. Selectivities of oxide to silicon are determined to increase with the inductive power, and are found to be the highest at the intermediate pressure of 10 mTorr. While the stoichiometry of the fluorocarbon films are critical factors in determining the overall etch rate behavior, the fluorocarbon film thickness on the polycrystalline and crystalline silicon is the dominant factor in determining the SiO[sub 2] over silicon etch selectivity. The mechanisms involved in attaining high selectivity are dominated by a defluorination of the fluorocarbon steady-state film on polycrystalline silicon, while maintaining a high ion current to the wafer. [copyright] [ital 1999 American Vacuum Society.

  18. Polymer radiation curing: epoxies, phenolics, fluorocarbons, and silicones. January 1970-February 1989 (Citations from the NTIS data base). Report for January 1970-February 1989

    SciTech Connect

    Not Available

    1989-02-01

    This bibliography contains citations concerning the processes and effects of radiation curing on the following polymers: epoxy resins, phenolics, fluorocarbons and silicones. Gamma, ultraviolet, and infrared radiation are emphasized; however, polymer crosslinking by such electromagnetic wave radiation as microwave, laser, vacuum irradiation and ionization is included. Influence of radiation-induced polymer curing on mechanical, electrical, and chemical properties of the polymers is also included. (This updated bibliography contains 303 citations, 13 of which are new entries to the previous edition.)

  19. Polymer radiation curing: epoxies, phenolics, fluorocarbons, and silicones. January 1970-January 1988 (citations from the NTIS data base). Report for January 1970-January 1988

    SciTech Connect

    Not Available

    1988-01-01

    This bibliography contains citations concerning the processes and effects of radiation curing on the following polymers: epoxy resins, phenolics, fluorocarbons, and silicones. Gamma, ultraviolet, and infrared radiation are emphasized; however, polymer crosslinking by such electromagnetic wave radiation as microwave, laser, vacuum irradiation, and ionization is included. Influence of radiation-induced polymer curing on mechanical, electrical, and chemical properties of the polymers is also included. (This updated bibliography contains 290 citations, 18 of which are new entries to the previous edition.)

  20. Light-responsive nanoparticles with wettability changing from hydrophobicity to hydrophilicity and their application towards highly hydrophilic fluorocarbon coatings

    NASA Astrophysics Data System (ADS)

    Lin, Baozhong; Zhou, Shuxue

    2015-12-01

    Novel functional silica nanoparticles (SiO2-NBS-F) with irreversible light-responsive wettability were prepared by grafting of a light-responsive silane coupling agent (NBS) and further bonding with hydrophobic segments via a click reaction. The NBS was synthesized using an o-nitrobenzyl alcohol derivative of the photolabile protecting group. The SiO2-NBS-F nanoparticles exhibited considerable change of wettability from near-superhydrophobicity to near-superhydrophilicity after UV irradiation. The changing mechanism of wettability was confirmed by UV-Vis absorption spectra and X-ray photoelectron spectra. The SiO2-NBS-F nanoparticles were incorporated into fluorocarbon FEVE coatings by simple mixing. The nanoparticles occurred at the surface of the dried coatings even though their content was as low as 5 wt%, being due to their low surface free energy. The wettability of the SiO2-NBS-F filled FEVE coatings could transform from hydrophobicity (WCA 106.4) to hydrophilicity (WCA 33.3) after UV irradiation. It demonstrates that SiO2-NBS-F nanoparticles are useful to acquire highly hydrophilic surface for organic coatings.

  1. Applications of a Chemically Adsorbed Monomolecular Layer Having a Fluorocarbon Chain as an Anti-Contamination Film

    NASA Astrophysics Data System (ADS)

    Ogawa, Kazufumi; Ohtake, Tadashi; Nomura, Takaiki; Soga, Mamoru; Mino, Norihisa

    2000-12-01

    Monomolecular layers having a fluorocarbon chain were developed and made suitable for practical use as anti-contamination films for glasses, such as front door window glass plates of automobiles and window glass plates of electric ovens or microwave ovens, and also for stainless steel applications, such as covers of electric rice cookers, by using a chemical adsorption technique for the first time in the world. The layer was anchored to the substrate surface through covalent bonds. Thus the layer did not peel off and was durable against rubbing and scratching. As the film thickness was from about 1 to 2 nm, the layer was also optically transparent and the luster and color tone of the substrates was maintained. The lowest surface tension obtained was 8.2 mN/m, which is about a half that of Teflon. Although thermo-durability was a little low in comparison with that of Teflon, the production cost was lower. Thus this anti-contamination film should be very useful in the field of anti-contamination surface treatment.

  2. Mesoporous fluorocarbon-modified silica aerogel membranes enabling long-term continuous CO2 capture with large absorption flux enhancements.

    PubMed

    Lin, Yi-Feng; Chen, Chien-Hua; Tung, Kuo-Lun; Wei, Te-Yu; Lu, Shih-Yuan; Chang, Kai-Shiun

    2013-03-01

    The use of a membrane contactor combined with a hydrophobic porous membrane and an amine absorbent has attracted considerable attention for the capture of CO2 because of its extensive use, low operational costs, and low energy consumption. The hydrophobic porous membrane interface prevents the passage of the amine absorbent but allows the penetration of CO2 molecules that are captured by the amine absorbent. Herein, highly porous SiO2 aerogels modified with hydrophobic fluorocarbon functional groups (?CF3 ) were successfully coated onto a macroporous Al2 O3 membrane; their performance in a membrane contactor for CO2 absorption is discussed. The SiO2 aerogel membrane modified with ?CF3 functional groups exhibits the highest CO2 absorption flux and can be continuously operated for CO2 absorption for extended periods of time. This study suggests that a SiO2 aerogel membrane modified with ?CF3 functional groups could potentially be used in a membrane contactor for CO2 absorption. Also, the resulting hydrophobic SiO2 aerogel membrane contactor is a promising technology for large-scale CO2 absorption during the post-combustion process in power plants. PMID:23417984

  3. Kinetics of Nanoscale Self-Assembly Measured on Liquid Drops by Macroscopic Optical Tensiometry: From Mercury to Water and Fluorocarbons.

    PubMed

    Haimov, Boris; Iakovlev, Anton; Glick-Carmi, Rotem; Bloch, Leonid; Rich, Benjamin B; Müller, Marcus; Pokroy, Boaz

    2016-03-01

    Various molecules are known to form self-assembled monolayers (SAMs) on the surface of liquids. We present a simple method of investigating the kinetics of such SAM formation on sessile drops of various liquids such as mercury, water and fluorocarbon. To measure the surface tension of the drops we used an optical tensiometer that calculates the surface tension from the axisymmetric drop shape and the Young-Laplace relation. In addition, we estimated the SAM surface coverage fraction from the surface tension measured by other techniques. With this methodology we were able to optically detect concentrations as low as tenths of ppb increments of SAM molecules in solution and to compare the kinetics of SAM formation measured as a function of molecule concentration or chain length. The analysis is performed in detail for the case of alkanethiols on mercury and then shown to be more general by investigating the case of SAM formation of stearic acid on a water droplet in hexadecane and of perfluorooctanol on a Fluorinert FC-40 droplet in ethanol. PMID:26790500

  4. Shape Modification of Water-in-CO2 Microemulsion Droplets through Mixing of Hydrocarbon and Fluorocarbon Amphiphiles.

    PubMed

    Yan, Ci; Sagisaka, Masanobu; Rogers, Sarah E; Hazell, Gavin; Peach, Jocelyn; Eastoe, Julian

    2016-02-16

    An oxygen-rich hydrocarbon (HC) amphiphile has been developed as an additive for supercritical CO2 (scCO2). The effects of this custom-designed amphiphile have been studied in water-in-CO2 (w/c) microemulsions stabilized by analogous fluorocarbon (FC) surfactants, nFG(EO)2, which are known to form spherical w/c microemulsion droplets. By applying contrast-variation small-angle neutron scattering (CV-SANS), evidence has been obtained for anisotropic structures in the mixed systems. The shape transition is attributed to the hydrocarbon additive, which modifies the curvature of the mixed surfactant films. This can be considered as a potential method to enhance physicochemical properties of scCO2 through elongation of w/c microemulsion droplets. More importantly, by studying self-assembly in these mixed systems, fundamental understanding can be developed on the packing of HC and FC amphiphiles at water/CO2 interfaces. This provides guidelines for the design of fluorine-free CO2 active surfactants, and therefore, practical industrial scale applications of scCO2 could be achieved. PMID:26807476

  5. Influence of the 316 L stainless steel interface on the stability and barrier properties of plasma fluorocarbon films.

    PubMed

    Lewis, François; Cloutier, Maxime; Chevallier, Pascale; Turgeon, Stéphane; Pireaux, Jean-Jacques; Tatoulian, Michael; Mantovani, Diego

    2011-07-01

    Coatings are known to be one of the more suited strategies to tailor the interface between medical devices and the surrounding cells and tissues once implanted. The development of coatings and the optimization of their adhesion and stability are of major importance. In this work, the influence of plasma etching of the substrate on a plasma fluorocarbon ultrathin coating has been investigated with the aim of improving the stability and the corrosion properties of coated medical devices. The 316 L stainless steel interface was subjected to two different etching sequences prior to the plasma deposition. These plasma etchings, with H(2) and C(2)F(6) as gas precursors, modified the chemical composition and the thickness of the oxide layer and influenced the subsequent polymerization. The coating properties were evaluated using flat substrates submitted to deformation, aging into aqueous medium and corrosion tests. X-ray photoelectron spectroscopy (XPS), time of flight-secondary ion mass spectrometry (ToF-SIMS), ellipsometry, and atomic force microscopy (AFM) were performed to determine the effects of the deformation and the aging on the chemistry and morphology of the coated samples. Analyses showed that plasma etchings were essential to promote reproducible polymerization and film growth. However, the oxide layer thinning due to the etching lowered the corrosion resistance of the substrate and affected the stability of the interface. Still, the deformed samples did not exhibited adhesion and cohesion failure before and after the aging. PMID:21545130

  6. The cooling capabilities of C2F6/C3F8 saturated fluorocarbon blends for the ATLAS silicon tracker

    NASA Astrophysics Data System (ADS)

    Bates, R.; Battistin, M.; Berry, S.; Bitadze, A.; Bonneau, P.; Bousson, N.; Boyd, G.; Botelho-Direito, J.; Crespo-Lopez, O.; DiGirolamo, B.; Doubek, M.; Giugni, D.; Hallewell, G.; Lombard, D.; Katunin, S.; McMahon, S.; Nagai, K.; Robinson, D.; Rossi, C.; Rozanov, A.; Vacek, V.; Zwalinski, L.

    2015-03-01

    We investigate and address the performance limitations of the ATLAS silicon tracker fluorocarbon evaporative cooling system operation in the cooling circuits of the barrel silicon microstrip (SCT) sub-detector. In these circuits the minimum achievable evaporation temperatures with C3F8 were higher than the original specification, and were thought to allow an insufficient safety margin against thermal runaway in detector modules subject to a radiation dose initially foreseen for 10 years operation at LHC. We have investigated the cooling capabilities of blends of C3F8 with molar admixtures of up to 25% C2F6, since the addition of the more volatile C2F6 component was expected to allow a lower evaporation temperature for the same evaporation pressure.A custom built recirculator allowed the in-situ preparation of C2F6/C3F8 blends. These were circulated through a representative mechanical and thermal setup reproducing an as-installed ATLAS SCT barrel tracker cooling circuit. Blend molar compositions were verified to a precision of 3.10-3 in a custom ultrasonic instrument.Thermal measurements in a range of C2F6/C3F8 blends were compared with measurements in pure C3F8. These indicated that a blend with 25% C2F6 would allow a reduction in evaporation temperature of around 9oC to below -15oC, even at the highest module power dissipations envisioned after 10 years operation at LHC. Such a reduction would allow more than a factor two in safety margin against temperature dependant leakage power induced thermal runaway.Furthermore, a blend containing up to 25% C2F6 could be circulated without changes to the on-detector elements of the existing ATLAS inner detector evaporative cooling system.

  7. Hybrid fluorocarbon-hydrocarbon CO2-philic surfactants. 2. formation and properties of water-in-CO2 microemulsions.

    PubMed

    Dupont, Audrey; Eastoe, Julian; Martin, Laura; Steytler, David C; Heenan, Richard K; Guittard, Frederic; Taffin de Givenchy, Elisabeth

    2004-11-01

    Hybrid fluorocarbon-hydrocarbon (F-H) sulfate surfactants are shown to be efficient stabilizers in water-in-CO2 (w/c) microemulsions. The chain structure and F-H ratio affect the regions of P-T phase stability and aggregation structure in these w/c phases. High-pressure near-infrared spectroscopy and small-angle neutron scattering measurements of microemulsified water provide evidence for the stabilization of w/c microemulsion droplets. The relative lengths of the two chains were found to influence the favored aggregation structure: for symmetric chain surfactants (F8H8, F7H7) spherical reverse micelles are present, but for asymmetric chain surfactants (F7H4, F8H4) extended cylinder aggregates form. These changes in aggregation are consistent with different surfactant packing parameters owing to the controlled variations in molecular structure. Furthermore, the general order of w/c phase transition pressures (F8H8 < F7H7 and F8H4 < F7H4) is in line with estimations of surfactant fractional free volume, as proposed by Johnston et al. (J. Phys. Chem. B 2004, 108, 1962-1966). Studies of adsorption at the poly(dimethylsiloxane)-water interface are shown to be valuable for assessing the CO2-philicity of new surfactants. All in all, the symmetric F8H8 and F7H7 analogues are seen to be the most efficient compounds from this class for applications in CO2. PMID:15518481

  8. Fluorocarbon assisted atomic layer etching of SiO{sub 2} using cyclic Ar/C{sub 4}F{sub 8} plasma

    SciTech Connect

    Metzler, Dominik; Oehrlein, Gottlieb S.; Bruce, Robert L.; Engelmann, Sebastian; Joseph, Eric A.

    2014-03-15

    The authors demonstrate atomic layer etching of SiO{sub 2} using a steady-state Ar plasma, periodic injection of a defined number of C{sub 4}F{sub 8} molecules, and synchronized plasma-based Ar{sup +} ion bombardment. C{sub 4}F{sub 8} injection enables control of the deposited fluorocarbon (FC) layer thickness in the one to several ngstrom range and chemical modification of the SiO{sub 2} surface. For low energy Ar{sup +} ion bombardment conditions, the physical sputter rate of SiO{sub 2} vanishes, whereas SiO{sub 2} can be etched when FC reactants are present at the surface. The authors have measured for the first time the temporal variation of the chemically enhanced etch rate of SiO{sub 2} for Ar{sup +} ion energies below 30?eV as a function of fluorocarbon surface coverage. This approach enables controlled removal of ngstrom-thick SiO{sub 2} layers. Our results demonstrate that development of atomic layer etching processes even for complex materials is feasible.

  9. Thermochemical Properties Enthalpy, Entropy, and Heat Capacity of C1-C4 Fluorinated Hydrocarbons: Fluorocarbon Group Additivity.

    PubMed

    Wang, Heng; Castillo, lvaro; Bozzelli, Joseph W

    2015-07-23

    Enthalpies of formation for 14 C2C4 fluorinated hydrocarbons were calculated with nine popular ab initio and density functional theory methods: B3LYP, CBS-QB3, CBS-APNO, M06, M06-2X, ?B97X, G4, G4(MP2)-6X, and W1U via several series of isodesmic reactions. The recommended ideal gas phase ?Hf298 (kcal mol(1)) values calculated in this study are the following: ?65.4 for CH3CH2F; ?70.2 for CH3CH2CH2F; ?75.3 for CH3CHFCH3; ?75.2 for CH3CH2CH2CH2F; ?80.3 for CH3CHFCH2CH3; ?108.1 for CH2F2; ?120.9 for CH3CHF2; ?125.8 for CH3CH2CHF2; ?133.3 for CH3CF2CH3; ?166.7 for CHF3; ?180.5 for CH3CF3; ?185.5 for CH3CH2CF3; ?223.2 for CF4; and ?85.8 for (CH3)3CF. Entropies (S298 in cal mol(1) K(1)) were estimated using B3LYP/6-31+G(d,p) computed frequencies and geometries. Rotational barriers were determined and hindered internal rotational contributions for S298, and Cp(T) were calculated using the rigid rotor harmonic oscillator approximation, with direct integration over energy levels of the intramolecular rotation potential energy curve. Thermochemical properties for the fluorinated carbon groups C/C/F/H2, C/C2/F/H, C/C/F2/H, C/C2/F2, and C/C/F3 were derived from the above target fluorocarbons. Previously published enthalpies and groups for 1,2-difluoroethane, 1,1,2-trifluoroethane, 1,1,2,2-tetrafluoroethane, 1,1,1,2-tetrafluoroethane, 1,1,1,2,2-pentafluoroethane, 2-fluoro-2-methylpropane that were previously determined via work reaction schemes are revised using updated reference species values. Standard deviations are compared for the calculation methods. PMID:26066097

  10. X-ray photoelectron spectroscopic study of Ge{sub 2}Sb{sub 2}Te{sub 5} etched by fluorocarbon inductively coupled plasmas

    SciTech Connect

    Kang, S.-K.; Oh, J. S.; Park, B. J.; Kim, S. W.; Lim, J. T.; Yeom, G. Y.; Kang, C. J.; Min, G. J.

    2008-07-28

    X-ray photoelectron spectroscopy was used to determine the level of surface fluorination damage of Ge{sub 2}Sb{sub 2}Te{sub 5} (GST) etched by fluorocarbon gases at different F/C ratios. When blank GST was etched, the gas with a higher F/C ratio produced a thinner C-F polymer on the etched surface but fluorinated Ge, Sb, and Te compounds were observed in the remaining GST. When the sidewall of the etched GST features was investigated, a thicker fluorinated layer was observed on the GST sidewall etched by the higher F/C ratio gas, indicating more fluorination due to the difficulty in preventing F diffusion into the GST through the thinner C-F layer.

  11. Hydrophobicity attainment and wear resistance enhancement on glass substrates by atmospheric plasma-polymerization of mixtures of an aminosilane and a fluorocarbon

    NASA Astrophysics Data System (ADS)

    Mgica-Vidal, Rodolfo; Alba-Elas, Fernando; Sainz-Garca, Elisa; Pantoja-Ruiz, Mariola

    2015-08-01

    Mixtures of different proportions of two liquid precursors were subjected to plasma-polymerization by a non-thermal atmospheric jet plasma system in a search for a coating that achieves a hydrophobic character on a glass substrate and enhances its wear resistance. 1-Perfluorohexene (PFH) was chosen as a low-surface-energy precursor to promote a hydrophobic character. Aminopropyltriethoxysilane (APTES) was chosen for its contribution to the improvement of wear resistance by the formation of siloxane bonds. The objective of this work was to determine which of the precursors' mixtures that were tested provides the coating with the most balanced enhancement of both hydrophobicity and wear resistance, given that coatings deposited with fluorocarbon-based precursors such as PFH are usually low in resistance to wear and coatings deposited with APTES are generally hydrophilic. The coatings obtained were analyzed by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Fourier Transform Infra-Red (FTIR) spectroscopy, X-ray Photoelectron Spectroscopy (XPS), static Water Contact Angle (WCA) measurements, tribological ball-on-disc tests and contact profilometry. A relationship between the achievement of a hydrophobic character and the modifications to roughness and surface morphology and the incorporation of fluorocarbon groups in the surface chemistry was observed. Also, it was seen that the wear resistance was influenced by the SiOSi content of the coatings. In turn, the SiOSi content appears to be directly related to the percentage of APTES used in the mixture of precursors. The best conjunction of hydrophobicity and wear resistance in this work was found in the sample that was coated using a mixture of APTES and PFH in proportions of 75 and 25%, respectively. Its WCA (100.2 7.5) was the highest of all samples that were measured and more than three times that of the uncoated glass (31 0.7). This sample underwent a change from a hydrophilic to a hydrophobic character. It also had the lowest wear rate of the hydrophobic samples obtained in this work, with a reduction of 28.8% in the wear rate of the uncoated glass.

  12. Reductive defluorination of saturated fluorocarbons by organometallic reagents and aryl halide coordination to tungsten(II) and molybdenum(II) by chelating Schiff base ligands

    SciTech Connect

    Harrison, R.G.

    1993-01-01

    Strong organometallic nucleophiles cleave C-F bonds of fluorocarbons such as perfluorodecalin and perfluoro(methylcyclohexane) to afford complexes of the form Cp(CO)[sub 2]FeR, where R is a fluoro aromatic derivative of the perfluorocarbon, when NaCpFe(CO)[sub 2] is used as a nucleophile. Fluoride ion and [Cp(CO)[sub 2]Fe][sub 2] are also recovered in good yields. The reaction occurs at ambient temperature and reaction times vary from one to four hours depending on the substrate used. An electron transfer mechanism is proposed and radical character exists in the intermediates, as evident by hydrogen incorporation into the fluorocarbon products and rate enhancement when the reaction is run in the presence of a hydrogen radical donor. The reactivity patterns of model systems indicate hydrogen incorporation occurred early along the reaction pathway. NaRe(CO)[sub 5] and Ni(P(C[sub 2]H[sub 5])[sub 3])[sub 4] also show reactivity towards the perfluorosubstrates, but NaCpMo(CO)[sub 3] and Na[sub 2]Fe(CO)[sub 4] do not. Aryl-X (X = Cl, Br, I, OCH[sub 3]) groups coordinate to Mo(II) and W(II), through the lone pairs on the atoms, forming seven coordinate metal carbonyls, when chelating nitrogen Schiff base ligands are oxidatively added to W(CO)[sub 3](NCCH[sub 3])[sub 3] or Mo(CO)[sub 3](toluene) in THF. The major mode of reactivity of these coordination compounds is aryl halide dissociation. Competition with typical solvents as monitored by solution IR and ligand equilibrium studies give relative bond strengths. X-ray crystallography shows covalent bonding between the metal and aryl halide groups and the metal geometry is capped octahedral. The aryl halide complexes substitute CO preferentially over the aryl halide when exposed to phosphine donor ligands. Aryl-fluoride coordination was not detected, but halide bridged metal dimers were isolated instead.

  13. Neutral gas temperature measurements of high-power-density fluorocarbon plasmas by fitting swan bands of C{sub 2} molecules

    SciTech Connect

    Bai Bo; Sawin, Herbert H.; Cruden, Brett A.

    2006-01-01

    The neutral gas temperature of fluorocarbon plasmas in a remote toroidal transformer-coupled source was measured to be greater than 5000 K, under the conditions of a power density greater than 15 W/cm{sup 3} and pressures above 2 torr. The rovibrational bands of C{sub 2} molecules (swan bands, d {sup 3}{pi}{sub g}{yields}a {sup 3}{pi}{sub u}) were fitted to obtain the rotational temperature that was assumed to equal the translational temperature. This rotational-translational temperature equilibrium assumption was supported by the comparison with the rotational temperature of second positive system of added N{sub 2}. For the same gas mixture, the neutral gas temperature is nearly a linear function of plasma power, since the conduction to chamber wall and convection are the major energy-loss processes, and they are both proportional to neutral gas temperature. The dependence of the neutral gas temperature on O{sub 2} flow rate and pressure can be well represented through the power dependence, under the condition of constant current operation. An Arrhenius type of dependence between the etching rate of oxide film and the neutral gas temperature is observed, maybe indicating the importance of the pyrolytic dissociation in the plasma formation process when the temperature is above 5000 K.

  14. Fluorocarbon assisted atomic layer etching of SiO2 and Si using cyclic Ar/C4F8 and Ar/CHF3 plasma

    DOE PAGESBeta

    Metzler, Dominik; Li, Chen; Engelmann, Sebastian; Bruce, Robert L.; Joseph, Eric A.; Oehrlein, Gottlieb S.

    2015-11-11

    The need for atomic layer etching (ALE) is steadily increasing as smaller critical dimensions and pitches are required in device patterning. A flux-control based cyclic Ar/C4F8 ALE based on steady-state Ar plasma in conjunction with periodic, precise C4F8 injection and synchronized plasma-based low energy Ar+ ion bombardment has been established for SiO2.1 In this work, the cyclic process is further characterized and extended to ALE of silicon under similar process conditions. The use of CHF3 as a precursor is examined and compared to C4F8. CHF3 is shown to enable selective SiO2/Si etching using a fluorocarbon (FC) film build up. Othermore » critical process parameters investigated are the FC film thickness deposited per cycle, the ion energy, and the etch step length. Etching behavior and mechanisms are studied using in situ real time ellipsometry and X-ray photoelectron spectroscopy. Silicon ALE shows less self-limitation than silicon oxide due to higher physical sputtering rates for the maximum ion energies used in this work, ranged from 20 to 30 eV. The surface chemistry is found to contain fluorinated silicon oxide during the etching of silicon. As a result, plasma parameters during ALE are studied using a Langmuir probe and establish the impact of precursor addition on plasma properties.« less

  15. Impact of etching kinetics on the roughening of thermal SiO{sub 2} and low-k dielectric coral films in fluorocarbon plasmas

    SciTech Connect

    Yin Yunpeng; Sawin, Herbert H.

    2007-07-15

    The impact of etching kinetics and etching chemistries on surface roughening was investigated by etching thermal silicon dioxide and low-k dielectric coral materials in C{sub 4}F{sub 8}/Ar plasma beams in an inductive coupled plasma beam reactor. The etching kinetics, especially the angular etching yield curves, were measured by changing the plasma pressure and the feed gas composition which influence the effective neutral-to-ion flux ratio during etching. At low neutral-to-ion flux ratios, the angular etching yield curves are sputteringlike, with a peak around 60 deg. -70 deg. off-normal angles; the surface at grazing ion incidence angles becomes roughened due to ion scattering related ion-channeling effects. At high neutral-to-ion flux ratios, ion enhanced etching dominates and surface roughening at grazing angles is mainly caused by the local fluorocarbon deposition induced micromasking mechanism. Interestingly, the etched surfaces at grazing angles remain smooth for both films at intermediate neutral-to-ion flux ratio regime. Furthermore, the oxygen addition broadens the region over which the etching without roughening can be performed.

  16. Investigation of the roles of gas-phase CF{sub 2} molecules and F atoms during fluorocarbon plasma processing of Si and ZrO{sub 2} substrates

    SciTech Connect

    Cuddy, Michael F.; Fisher, Ellen R.

    2010-08-15

    The molecular-level chemistry involved in the processing of silicon and zirconia substrates by inductively coupled fluorocarbon (FC) plasmas produced from CF{sub 4} and C{sub 2}F{sub 6} precursors has been explored. The roles of gas-phase excited, neutral, and ionic species, especially CF{sub 2} and F, were examined as they contribute to FC film formation and substrate etching. The surface reactivity of CF{sub 2} radicals in C{sub 2}F{sub 6} plasmas has a dependence on substrate material and plasma system, as measured by our imaging of radicals interacting with surfaces (IRIS) technique. Relative concentrations of excited state species are also dependent upon substrate type. Moreover, differences in the nature and concentrations of gas-phase species in CF{sub 4} and C{sub 2}F{sub 6} plasmas contribute to markedly different surface compositions for FC films deposited on substrates as revealed from x-ray photoelectron spectroscopic analysis. These data have led to the development of a scheme that illustrates the mechanisms of film formation and destruction in these FC/substrate systems with respect to CF{sub 2} and F gas-phase species and also Si and ZrO{sub 2} substrates.

  17. Fluorocarbon assisted atomic layer etching of SiO2 and Si using cyclic Ar/C4F8 and Ar/CHF3 plasma

    SciTech Connect

    Metzler, Dominik; Li, Chen; Engelmann, Sebastian; Bruce, Robert L.; Joseph, Eric A.; Oehrlein, Gottlieb S.

    2015-11-11

    The need for atomic layer etching (ALE) is steadily increasing as smaller critical dimensions and pitches are required in device patterning. A flux-control based cyclic Ar/C4F8 ALE based on steady-state Ar plasma in conjunction with periodic, precise C4F8 injection and synchronized plasma-based low energy Ar+ ion bombardment has been established for SiO2.1 In this work, the cyclic process is further characterized and extended to ALE of silicon under similar process conditions. The use of CHF3 as a precursor is examined and compared to C4F8. CHF3 is shown to enable selective SiO2/Si etching using a fluorocarbon (FC) film build up. Other critical process parameters investigated are the FC film thickness deposited per cycle, the ion energy, and the etch step length. Etching behavior and mechanisms are studied using in situ real time ellipsometry and X-ray photoelectron spectroscopy. Silicon ALE shows less self-limitation than silicon oxide due to higher physical sputtering rates for the maximum ion energies used in this work, ranged from 20 to 30 eV. The surface chemistry is found to contain fluorinated silicon oxide during the etching of silicon. As a result, plasma parameters during ALE are studied using a Langmuir probe and establish the impact of precursor addition on plasma properties.

  18. 21 CFR 177.1380 - Fluorocarbon resins.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 1 CFR part 51. Copies may be obtained from the American Society for Testing and Materials, 1916 Race... practice, those food-contact articles intended for repeated use shall be thoroughly cleansed prior to...

  19. 21 CFR 177.1380 - Fluorocarbon resins.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 1 CFR part 51. Copies may be obtained from the American Society for Testing and Materials, 1916 Race... practice, those food-contact articles intended for repeated use shall be thoroughly cleansed prior to...

  20. 21 CFR 177.1380 - Fluorocarbon resins.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 1 CFR part 51. Copies may be obtained from the American Society for Testing and Materials, 1916 Race... practice, those food-contact articles intended for repeated use shall be thoroughly cleansed prior to...

  1. 21 CFR 177.1380 - Fluorocarbon resins.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Materials,” which is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies..., those food-contact articles intended for repeated use shall be thoroughly cleansed prior to their...

  2. 21 CFR 177.1380 - Fluorocarbon resins.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 1 CFR part 51. Copies may be obtained from the American Society for Testing and Materials, 1916 Race... practice, those food-contact articles intended for repeated use shall be thoroughly cleansed prior to...

  3. Flammability limits of fuel/fluorocarbon azeotropes

    SciTech Connect

    Alvares, N.J.; Hammond, P.R.; Foote, K.; Ford, H.W. Jr.

    1981-02-10

    Both Dehn and Thorne have intimated that flash point (FP) measurements could be used to define the gas-phase flammability limits of fire and retardant vapor mixtures above the surface of heated retardant containing flammable liquids. However, it was found that ignitable mixtures exist above the liquid surface, where the concentration of the agent in the fluid is well beyond the limiting concentrating for inerting of alcohol fires. Clearly this anomaly results from diffusion competition of air and liquid vapor mixture at the position of the ignitor, as influenced by the design of the experimental apparatus. The authors are skeptical about the need or worth of attempting to define flammability limits using FP data, especially since unknown variables control the response. More important is to define the concentration of liquid phase retardant that will affect gas phase inerting. Thus, it is necessary to continue practical testing of retardant-containing liquids for their effectiveness in mitigating possible accidents, e.g., the next phase of this work will assess the effectiveness of halocarbons to inert high-pressure alcohol/agent leaks impinging on both electrical and flame ignition sources.

  4. Fluorocarbon-modified water-soluble cellulose derivatives

    SciTech Connect

    Hwang, F.S.; Hogen-Esch, T.E. . Loker Hydrocarbon Research Inst. and Dept. of Chemistry)

    1993-06-07

    1,1-Dihydroperfluorobutyl,1,1-dihydroperfluorooctyl, and octyl derivatives of (hydroxyethyl)-cellulose (HEC) were prepared by reaction of the Na salt of HEC in aqueous isopropyl alcohol with 1,1-dihydroperfluorobutyl or octyl p-toluenesulfonate (4 or 5), with 1,1-dihydroperfluorobutyl or octyl glycidyl ether or (8 or 9), and with octyl glycidyl ether (12). The degrees of substitution of HEC were determined using [sup 19]FNMR and varied between 0.023 and 1.20 mol % of anhydroglucose units (AGU). The HEC derivatives modified with 4, 5, and 8 were sparingly soluble or insoluble, and their aqueous solutions were generally low in viscosity. In contrast solutions of HEC modified with 9 did have significantly enhanced viscosities with respect to unmodified HEC or compared to HEC modified with the octyl glycidyl ether, having the same chain length as 9. The Brookfield viscosity plotted against perfluorocarbon content of aqueous solutions of HEC modified with 9 was shown to go through a maximum at about 0.42 mol % (0.92 wt %) with respect to AGU's. The solutions of this and similar polymers were shown to be highly pseudoplastic. Furthermore, increases in viscosity were observed upon addition to NaCl. These observations are consistent with the very strong intermolecular hydrophobic association of the perfluorocarbon groups.

  5. Role of surface temperature in fluorocarbon plasma-surface interactions

    SciTech Connect

    Nelson, Caleb T.; Overzet, Lawrence J.; Goeckner, Matthew J.

    2012-07-15

    This article examines plasma-surface reaction channels and the effect of surface temperature on the magnitude of those channels. Neutral species CF{sub 4}, C{sub 2}F{sub 6}, and C{sub 3}F{sub 8} are produced on surfaces. The magnitude of the production channel increases with surface temperature for all species, but favors higher mass species as the temperature is elevated. Additionally, the production rate of CF{sub 2} increases by a factor of 5 as the surface temperature is raised from 25 Degree-Sign C to 200 Degree-Sign C. Fluorine density, on the other hand, does not change as a function of either surface temperature or position outside of the plasma glow. This indicates that fluorine addition in the gas-phase is not a dominant reaction. Heating reactors can result in higher densities of depositing radical species, resulting in increased deposition rates on cooled substrates. Finally, the sticking probability of the depositing free radical species does not change as a function of surface temperature. Instead, the surface temperature acts together with an etchant species (possibly fluorine) to elevate desorption rates on that surface at temperatures lower than those required for unassisted thermal desorption.

  6. Photoluminescence of silicone oil treated by fluorocarbon plasma

    NASA Astrophysics Data System (ADS)

    Chen, Tian; Ye, Chao; Yuan, Ying; Deng, Yan-Hong; Ge, Shui-Bin; Xu, Yi-Jun; Ning, Zhao-Yuan; Pan, Xiao-Ping; Wang, Zhen-Ming

    2012-09-01

    We investigated photoluminescence characteristics of silicone oils treated by C2F6 and CHF3 plasma. The silicone oil treated by the C2F6 plasma emitted a white light mainly composed of 415 nm, 469 nm, and 554 nm emissions, while that treated by the CHF3 plasma emitted a pink light (415 nm). Fourier transformed infrared spectroscopy and Raman spectroscopy studies showed that the photoluminescence was correlated with the SiC bond, the carbon-related defects and the oxygen vacancies. It was suggested that the light emitting at 554 nm was related to the SiC bond and the carbon-related defects, while the pink emission at 415 nm was related to the oxygen vacancies.

  7. Thermal Conductivity of Nonazeotropic Gaseous Mixtures of Fluorocarbon Refrigerants

    NASA Astrophysics Data System (ADS)

    Tanaka, Yoshiyuki; Ueno, Hiroshi; Kubota, Hironobu; Makita, Tadashi

    The thermal conductivity of four binary gaseous mixtures of R22 (CHCIF2) with R13(CClF3), R23(CHF3), R12(CCl2F2) and R114(CClF2CClF2) has been measured at temperatures 298.15 and 323.15K under pressures from atmospheric to saturated pressures by a coaxial cylinder cell. The precision of the thermal conductivity obtained is within 2%. The thermal conductivity of mixtures increases with increasing temperature and pressure at a constant composition. The thermal conductivity in each mixture changes almost linearly with the concentration of R22 at a constant temperature and pressure, although the thermal conductivity at each composition is slightly larger than the calculated values by a simple molefraction average method. The experimental results were correlated with composition and pressure by empirical equations and compared with several kinds of prediction methods. The Brokaw's equation is found to reproduce the experimental data most successfully with a mean deviation of 0.7%.

  8. Estimated historic emissions of fluorocarbons from the European Union

    NASA Astrophysics Data System (ADS)

    McCulloch, A.; Midgley, P. M.

    Emissions of chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) and one hydrofluorocarbon (HFC-134a) from Europe have been estimated for the years 1986-1996 with a precision in most cases better than ±20%. During that period, sales of CFCs have reduced to virtually zero but they are still being emitted from the "bank" in use in equipment. These emissions are calculated to have fallen dramatically; however the largest releases are still of CFC-11, at 44,000 tonnes in 1996. Significant contributions to the total emission of ozone depleting substances from the European Union during 1996 were also made by HCFC-22 (35,000 tonnes) and CFC-12 (9000 tonnes); releases of other CFCs and HCFCs into the atmosphere from the EU are markedly less. On the other hand, emissions of HFC-134a (which is not an ozone depleting substance) would appear to be growing rapidly and could have reached 12,000 tonnes yr -1 in 1996. HFC-134a is a replacement for CFC-12, releases of which are calculated to have declined much more than the growth in HFC-134a. This leads to the conclusion that substitution of one by the other has been much less than 100% and is actually smaller than had been projected by market research in the early 1990s.

  9. Ferroelectrets with improved thermal stability made from fused fluorocarbon layers

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Hillenbrand, J.; Sessler, G. M.

    2007-03-01

    Several layers of polytetrafluoroethylene and fluoroethylenepropylene films are fused such that small interfacial gas voids are formed between the layers. After proper charging and annealing, the fused multilayer films show large and thermally stable quasistatic piezoelectric d33 coefficients of about 1000pC/N which are subject to a minor reduction of 3% per day if exposed to 90C. Depending on sample processing, the piezoelectric coefficient is relatively independent of applied pressure in the range up to 20kPa and of applied frequency up to about 100kHz. Thermally-stimulated discharge measurements indicate that the decay of the piezoelectric activity at higher temperatures is at least partially due to charge drift along the surfaces of the voids. A microphone built with the cellular ferroelectrets has a sensitivity of 3mV/Pa at 1kHz.

  10. [Pharmacodynamic equivalence and clinical trial of a new fluorocarbon-free glycerol trinitrate pump spray with low ethanol content in comparison to a fluorocarbon-containing reference spray and a fluorocarbon-free pump spray with high ethanol content].

    PubMed

    Erb, K; de Mey, C; Zimmermann, T; Mutschler, H; Roll, S; Belz, G G

    1994-04-01

    The pharmacodynamic equivalence of a fluorohydrocarbons-(FCH)-free glyceryl trinitrate (GTN, CAS 55-63-0)-containing pump spray with low ethanol content (Nitrolingual-Spray N; TL) versus a conventional FCH-containing GTN spray (Nitrolingual-Spray, R) as reference and a FCH-free GTN pump spray with high ethanol content (TH) was investigated by digital plethysmography (DPG) in a double-blinded, placebo-controlled (TL-matched placebo spray), randomized, period-balanced, 4-way cross-over design. Additionally the clinical tolerability (as perceived by the subjects and reported to the treatments-administrating investigator) was determined. The DPG-changes (cla; ratio of c-incisure and systolic a-wave) after the sublingual (s.l.) administration of 0.8 mg GTN of TL were biostatistically equivalent with R: the confidence intervals (CI) of the point estimates of the maximal decrease in cla (TL/R: 0.98, 90%-CI: 0.84 to 1.14) and the area-weighted average decrease in cla (TL/R: 0.97, 90%-CI: 0.80-1.16) were well in a 80-125% tolerance range. The time of occurrence of the maximal DPG-effect of TL was not different from R (distribution-free estimate of the difference TL-R: -2.25 min, 95%-CI: -9.5 min to 2 min). In contrast the maximal DPG-effect of TH after the s.l. administration of 0.8 mg GTN had a statistically significant earlier onset (TH-R: -6 min, 95%-CI: -9.5 min to -2 min) and a higher area-weighted average response (TH/R: 1.12, 90%-CI: 0.95 to 1.34). TH consistently caused an utterly unpleasant burning sensation in the mouth, thus this perceived local discomfort was distinctly different compared to all other treatments.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8011000

  11. Short- and long-term releases of fluorocarbons from disposal of polyurethane foam waste.

    PubMed

    Kjeldsen, Peter; Scheutz, Charlotte

    2003-11-01

    Several halocarbons having very high global warming or ozone depletion potentials have been used as a blowing agent (BA) for insulation foam in home appliances, such as refrigerators and freezers. Many appliances are shredded after the end of their useful life. Release experiments carried out in the laboratory on insulation foam blown with the blowing agents CFC-11, HCFC-141b, HCF-134fa, and HFC-245fa revealed that not all blowing agents are released during a 6-week period following the shredding process. The experiments confirmed the hypothesis that the release could be divided into three segments: By shredding foam panels, a proportion of the closed cells is either split or damaged to a degree allowing for a sudden release of the contained atmosphere in the cell (the instantaneous release). Cells adjacent to the cut surface may be only slightly damaged by tiny cracks or holes allowing a relative slow release of the BA to the surroundings (the short-term release). A significant portion of the cells in the foam particle will be unaffected and only allows release governed by slow diffusion through the PUR cell wall (the long-term release). The magnitude of the releases is for all three types highly dependent on how fine the foam is shredded. The residual blowing agent remaining after the 6-week period may be very slowly released if the integrity of the foam particles with respect to diffusion properties is kept after disposal of the foam waste on landfills. It is shown by setting up a national model simulating the BA releases following decommissioning of used domestic refrigerators/freezers in the United States that the release patterns are highly dependent on how the appliances are shredded. PMID:14620840

  12. Fluorocarbon-hybrid pulmonary surfactants for replacement therapy--a Langmuir monolayer study.

    PubMed

    Nakahara, Hiromichi; Lee, Sannamu; Krafft, Marie Pierre; Shibata, Osamu

    2010-12-01

    Effective additives to pulmonary surfactant (PS) preparations for therapy of respiratory distress syndrome (RDS) are being intensively sought. We report here the investigation of the effects of partially fluorinated amphiphiles (PFA) on the surface behavior of a model PS formulation. When small amounts of a partially fluorinated alcohol C(8)F(17)C(m)H(2m)OH (F8HmOH, m = 5 and 11) are added to the PS model preparation (a dipalmitoylphosphatidylcholine (DPPC)/Hel 13-5 peptide mixture) considered here, the effectiveness of the latter in in vitro pulmonary functions is enhanced. The mechanism for the improved efficacy depends on the hydrophobic chain length of the added PFA molecules. The shorter PFA, F8H5OH, when incorporated in the monolayer of the PS model preparation, promotes a disordered liquid-expanded (LE) phase upon lateral compression (fluidization). In contrast, the addition of the longer PFA, F8H11OH, reduces the disordered LE/ordered liquid-condensed (LC) phase transition pressure and promotes the growth of ordered domains (solidification). Furthermore, compression-expansion cycles suggest that F8H5OH, when incorporated in the PS model preparation, undergoes an irreversible elimination into the subphase, whereas F8H11OH enhances the squeeze-out phenomenon of the SP-B mimicking peptide, which is important in pulmonary functions and is related to the formation of a solid-like monolayer at the surface and of a surface reservoir just below the surface. F8H11OH particularly reinforces the effectiveness of DPPC in terms of minimum reachable surface tension, and of preservation of the integrated hysteresis area between compression and expansion isotherms, the two latter parameters being generally accepted indices for assessing PS efficacy. We suggest that PFA amphiphiles may be useful potential additives for synthetic PS preparations destined for treatment of RDS in premature infants and in adults. PMID:21049919

  13. Surfactant formation efficiency of fluorocarbon-hydrocarbon oligomers in supercritical CO2.

    PubMed

    Can, Hatice; Kacar, Gokhan; Atilgan, Canan

    2009-09-28

    We use dissipative particle dynamics simulations to explore the phase behavior and solution properties of ABCBA type model surfactants in near-supercritical CO(2) environment. We present design guidelines for functional surfactants with tunable properties. The block co-oligomers used in this study are made up of a CO(2)-phobic block having ethyl propionate and nine different types of ethylene monomers, flanked on either side by eight repeat units of fluorinated CO(2)-philic blocks. The most promising design block co-oligomer in the series is that with the longest CO(2)-phobic group in the ethylene monomers. For this particular oligomer, we systematically analyze the effect of concentration on the self-assembly behavior. Spherical micelles form in the 5%-65% volume fraction range for this oligomer, with the highest number of spherical micelles occurring at 45% surfactant in CO(2). When the volume fraction of the surfactant is increased from 70% to 85%, cylindrical micelles occur. We further investigate the effect of the length of the solvophilic fluorinated segments on self-assembly and find that stable micelles occur in a window of 8-14 repeat units. We find that the most critical contribution to stability is due to the mixing free energy between the chain tails residing in the outer layers and the interpenetrating molecules. PMID:19791906

  14. [Action of the fluorocarbons, 12 (difluorodichloromethane) and 11 (monofluorotrichloromethane), on smooth muscle].

    PubMed

    Paulet, G; Lessard, Y

    1975-01-01

    We have studied the action of difluorodichloromethane (F12) and monofluorotrichloromethane (F11) on the rat isolated uterine muscle and the rabbit isolated duodenum. Both gases in the nutritive solution after the functioning of these organs in a way which is, moreover, non identical. On the uterus both gases show an inhibitory effect against the spontaneous contractions. On the duodenum, both gases inhibit the phasic contractions but the basal tonus is strongly increased by F12, and on the contrary reduced by F11. The action is a musculotrop one and quite reversible in every case. Both gases do not modify the action of acetylcholin, epinephrin and histamin. PMID:129214

  15. INDUSTRIAL PROCESS PROFILES FOR ENVIRONMENTAL USE: CHAPTER 16. THE FLUOROCARBON-HYDROGEN FLORIDE INDUSTRY

    EPA Science Inventory

    The catalog of Industrial Process Profiles for Environmental Use was developed as an aid in defining the environmental impacts of industrial activity in the United States. Entries for each industry are in consistent format and form separate chapters of the study. The materials of...

  16. Effects of water-soluble spacers on the hydrophobic association of fluorocarbon modified polyacrylamide

    SciTech Connect

    Hwang, F.S.; Hogen-Esch, T.E.

    1993-12-31

    A number of acrylamide-acrylate copolymers were synthesized in which the acrylate (CH{sub 2}=CHCOO(CH{sub 2}CH{sub 2}O){sub n}R{sub t}) is hydrophobic on account of the presence of a 1,1-dihydroperfluorooctyl group (R{sub F}) connected to the acrylate via a-(CH{sub 2}CH{sub 2}O){sub n} hydrophobic spacer (n=0-3). Copolymerization of the two comonomers was carried out in aqueous media in the presence of potassium perfluoro octanoate and acetone (10 vol%) and was initiated by sodium metabisufite and ammonium persulfate at 50{degrees}C. The Brookfield viscosities measured at 0.4 sec{sup {minus}1} as a function of comonomer molar content gave bell-shaped curves having maxima at .10-.15 mole% comonomer except for the comonomer without hydrophilic spacer (n=0) where the maximum is at .60 mole%. The viscosity maxima of the copolymers are quite dependent on the value of n giving the highest viscosities at n=3 (45,000 cp) that decreases value of n. The increased effectiveness of the longer spacers is attributed to decreased intermolecular excluded volume effects in the formation of the polymer assemblies.

  17. Regarding the effect that different hydrocarbon/fluorocarbon surfactant mixtures have on their complexation with HSA.

    PubMed

    Blanco, Elena; Messina, Paula; Ruso, Juan M; Prieto, Gerardo; Sarmiento, Flix

    2006-06-15

    The complexations between human serum albumin (HSA) and the sodium perfluorooctanoate/sodium octanoate and sodium perfluorooctanoate/sodium dodecanoate systems have been studied by a combination of electrical conductivity, ion-selective electrode, electrophoresis, and spectroscopy measurements. The binary mixtures of the surfactants deviated slightly from ideality. Binding plots revealed the existence of two specific binding sites, the first site being more accessible than the second. Positive cooperative binding has been found, thus revealing the importance of the hydrophobic interactions in both kinds of surfactants. The Gibbs energies of binding per mole of surfactant (DeltaG(nu)) were calculated from the Wyman binding potential where, on the basis of the elevated number of binding sites, a statistical contribution has been included. Initially these energies are large and negative, gradually decreasing as saturation is approached. Changes in the slope of Gibbs energies have been identified with the saturation of the first binding set. These facts denote that the surfactants under study have different favorite adsorption sites along the protein and that the adsorption process of perfluorooctanoate is more closely followed by dodecanoate than by octanoate. Finally, electrophoresis and spectroscopy measurements suggest induced conformational changes on HSA depending on the surfactant mixture as well as the mixed ratio. PMID:16771408

  18. K-Shell Ionization of Fluorocarbons Constituents by 2.0 MeV H^+.

    NASA Astrophysics Data System (ADS)

    Moreau, C.; Williams, A. M.; Shinpaugh, J. L.; Toburen, L. H.

    1997-11-01

    Cross sections for K-shell ionization of fluorine and carbon have been measured from Auger-electron yields for 2-MeV proton impact on CH_3F, CHF_3, CF_4, C_2F_6, and C_4F_8. Ejected electrons were electrostatically analyzed for electron-emission angles from 20^circ to 125^circ with respect to the incident beam. Absolute cross sections were determined by integrating the doubly differential yields with respect to emission angle and normalizing the resulting singly differential continuum-electron yields to Rutherford energy-loss cross sections at an electron energy of 1 KeV.(L.H. Toburen, S.T. Manson, and Y. Kim, Phys. Rev. A 17), 148 (1978). While large variations (up to a factor of two) of the fluorine K-shell ionization cross section have been previously reported for ionization in different fluorine-containing molecules ionized by He^+ ions,(Ghebremedhin, Ariyasinghe, and Powers, Phys. Rev. A 53), 1537 (1996). our proton-impact results show that the cross sections per fluorine atom differ by less than 20% for the molecules investigated.

  19. Double emulsions based on silicone-fluorocarbon-water and their skin penetration.

    PubMed

    Mahrhauser, Denise-Silvia; Fischer, Claudia; Valenta, Claudia

    2016-02-10

    Double emulsions have significant potential in pharmacy and cosmetics due to the feasibility of combining incompatible substances in one product and the protection of sensitive compounds by incorporating them into their innermost phase. However, a major drawback of double emulsions is their thermodynamic instability and their strong tendency to coalesce. In the present study, the physicochemical stability, the skin permeation and the skin penetration potential of modified semi-solid double emulsions was investigated. The double emulsions were prepared of the cosmetically applied perfluoropolyethers Fomblin(®) HC/04 or Fomblin(®) HC-OH, silicone, carbomer and water. Measurement of the droplet size and examination of the microscopic images confirmed their physicochemical stability over the observation period of eight weeks. Franz-type diffusion cell experiments revealed no increase in curcumin permeation due to the employed perfluoropolyethers compared to the respective control formulations. The formulations used as control were O/W macroemulsions with or without a Polysorbate 80/Sorbitane monooleate 80 surfactant combination. Likewise, tape stripping studies showed no penetration enhancing effect of the employed perfluoropolyethers which is desirable as both perfluoropolyethers are commonly applied components in human personal-care products. PMID:26688033

  20. New fluorocarbon elastomers for seals for geothermal and other aggressive environments

    SciTech Connect

    Dumitru, Earl T.; Lagow, R.J.; Kukacka L.E.

    1982-10-08

    Geothermal brines at 600 F which contain metallic salts, H{sub 2}S, and hydrocarbons quickly degrade conventional hydrocarbon elastomers, and hydrolyse crosslinks. Carbon-carbon and carbon-fluorine bonds are expected to be superior, but no such elastomer is now commercially available. We have prepared crosslinked, perfluorocarbon elastomers by radiation crosslinking VDFHFP and TFEP (alternating) copolymers in film and sheet form, and then converting C-H bonds to C-F bonds with elemental Fluorine gas. EPLM elastomers became brittle on fluorination. The best products exceeded 100 days survival at 300 C in simulated geothermal brine. Tensile, elongation, solvent swelling, and TCA methods were used to study the products.

  1. 40 CFR Appendix A to Subpart F of... - Specifications for Fluorocarbon and Other Refrigerants

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... existing refrigeration and air-conditioning products as required under 40 CFR part 82. 1.1.1Intent. This... following general classifications: 4.1.1Characterization a. Gas Chromatography b. Boiling point and boiling... chromatography (GC) as described in Appendix C to ARI Standard 700-1995. The chromatogram of the sample shall...

  2. 40 CFR Appendix A to Subpart F of... - Specifications for Fluorocarbon and Other Refrigerants

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... existing refrigeration and air-conditioning products as required under 40 CFR part 82. 1.1.1Intent. This... following general classifications: 4.1.1Characterization a. Gas Chromatography b. Boiling point and boiling... chromatography (GC) as described in Appendix C to ARI Standard 700-1995. The chromatogram of the sample shall...

  3. 40 CFR Appendix A to Subpart F of... - Specifications for Fluorocarbon and Other Refrigerants

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... existing refrigeration and air-conditioning products as required under 40 CFR part 82. 1.1.1Intent. This... following general classifications: 4.1.1Characterization a. Gas Chromatography b. Boiling point and boiling... chromatography (GC) as described in Appendix C to ARI Standard 700-1995. The chromatogram of the sample shall...

  4. 40 CFR Appendix A to Subpart F of... - Specifications for Fluorocarbon and Other Refrigerants

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... existing refrigeration and air-conditioning products as required under 40 CFR part 82. 1.1.1Intent. This... following general classifications: 4.1.1Characterization a. Gas Chromatography b. Boiling point and boiling... chromatography (GC) as described in Appendix C to ARI Standard 700-1995. The chromatogram of the sample shall...

  5. 40 CFR Appendix A to Subpart F of... - Specifications for Fluorocarbon and Other Refrigerants

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... existing refrigeration and air-conditioning products as required under 40 CFR part 82. 1.1.1Intent. This... following general classifications: 4.1.1Characterization a. Gas Chromatography b. Boiling point and boiling... chromatography (GC) as described in Appendix C to ARI Standard 700-1995. The chromatogram of the sample shall...

  6. Mineralization of chlorofluorocarbons and aromatization of saturated fluorocarbons by a convenient thermal process

    SciTech Connect

    Burdeniuc, J.; Crabtree, R.H.

    1996-01-19

    A chemical reaction has been discovered that mineralizes chlorofluorocarbons (CFCs) and enables the complete destruction of these environmentally hazardous species. The reaction products are easily handled solids, including recyclable alkali metal halides. Under milder conditions, the same reaction causes partial defluorination of cyclic perfluoroalkanes to yield perfluoroarenes, which are valuable chemical intermediates. The vaporized substrates are passed over a packed bed of heated sodium oxalate; heating at 270{degrees} to 290{degrees}C causes mineralization, whereas heating at 230{degrees}C causes aromatization. 12 refs., 1 fig., 1 tab.

  7. Sources of Hydrochlorofluorocarbons, Hydrofluorocarbons, and Fluorocarbons and Their Potential Emissions during the Next Twenty Five Years.

    ERIC Educational Resources Information Center

    McCulloch, Archie

    1994-01-01

    Examines the potential for the replacement of CFCs for historic uses with substituting technologies. The potential production and emissions of the principal HCFCs and HFCs are calculated for the next 25 years. (LZ)

  8. Correlating ion energies and CF{sub 2} surface production during fluorocarbon plasma processing of silicon

    SciTech Connect

    Martin, Ina T.; Zhou Jie; Fisher, Ellen R.

    2006-07-01

    Ion energy distribution (IED) measurements are reported for ions in the plasma molecular beam source of the imaging of radicals interacting with surfaces (IRIS) apparatus. The IEDs and relative intensities of nascent ions in C{sub 3}F{sub 8} and C{sub 4}F{sub 8} plasma molecular beams were measured using a Hiden PSM003 mass spectrometer mounted on the IRIS main chamber. The IEDs are complex and multimodal, with mean ion energies ranging from 29 to 92 eV. Integrated IEDs provided relative ion intensities as a function of applied rf power and source pressure. Generally, higher applied rf powers and lower source pressures resulted in increased ion intensities and mean ion energies. Most significantly, a comparison to CF{sub 2} surface interaction measurements previously made in our laboratories reveals that mean ion energies are directly and linearly correlated to CF{sub 2} surface production in these systems.

  9. Synthesis and biological screening by novel hybrid fluorocarbon hydrocarbon compounds for use as artificial blood substitutes

    NASA Technical Reports Server (NTRS)

    Moacanin, J.; Scherer, K.; Toronto, A.; Lawson, D.; Terranova, T.; Yavrouian, A.; Astle, L.; Harvey, S.; Kaaelble, D. H.

    1979-01-01

    A series of hybrid fluorochemicals of general structure R(1)R(2)R(3)CR(4) was prepared where the R(i)'s (i=1,2,3) is a saturated fluoroalkyl group of formula C sub N F sub 2n+1, and R(4) is an alkyl group C sub n H sub 2n+1 or a related moiety containing amino, ether, or ester functions but no CF bonds. Compounds of this class containing approximately eight to twenty carbons total have physical properties suitable for use as the oxygen carrying phase of fluorochemical emulsion artificial blood. The chemical synthesis, and physical and biological testing of pure single isomers of the proposed artificial blood candidate compounds are included. Significant results are given.

  10. ULTRASONIC CLEANING AS A REPLACEMENT FOR A CHLORO- FLUOROCARBON-BASED SYSTEM

    EPA Science Inventory

    This report describes the technical and economic evaluation of the replacement of a vapor degreasing system with an ultrasonic cleaning system to clean stainless steel components. Heated inorganic water-based cleaning fluid was utilized in lieu of a chlorofluorocarbon (CFC, freon...

  11. Preparation, characterization, physical testing and performance of fluorocarbon membranes and separators

    NASA Technical Reports Server (NTRS)

    Lagow, R. J.; Dumitru, E. T.

    1982-01-01

    The direct fluorination method of converting carefully selected hydrocarbon substrates to fluorinated membranes was successfully applied to produce promising, novel membranes for electrochemical devices. A family of polymer blends was identified which permits wide latitude in the concentration of both crosslinks and carboxyl groups in hydrocarbon membranes. These membranes were successfully fluorinated and are potentially competitive with commercial membranes in performance, and potentially much cheaper in price.

  12. An on-line acoustic fluorocarbon coolant mixture analyzer for the ATLAS silicon tracker

    SciTech Connect

    Bates, R.; Battistin, M.; Berry, S.; Bitadze, A.; Bonneau, P.; Bousson, N.; Boyd, G.; Botelho-Direito, J.; DiGirolamo, B.; Doubek, M.; Egorov, K.; Godlewski, J.; Hallewell, G.; Katunin, S.; Mathieu, M.; McMahon, S.; Nagai, K.; Perez-Rodriguez, E.; Rozanov, A.; Vacek, V.; Vitek, M.

    2011-07-01

    The ATLAS silicon tracker community foresees an upgrade from the present octafluoro-propane (C{sub 3}F{sub 8}) evaporative cooling fluid - to a composite fluid with a probable 10-20% admixture of hexafluoro-ethane (C{sub 2}F{sub 6}). Such a fluid will allow a lower evaporation temperature and will afford the tracker silicon substrates a better safety margin against leakage current-induced thermal runaway caused by cumulative radiation damage as the luminosity profile at the CERN Large Hadron Collider increases. Central to the use of this new fluid is a new custom-developed speed-of-sound instrument for continuous real-time measurement of the C{sub 3}F{sub 8}/C{sub 2}F{sub 6} mixture ratio and flow. An acoustic vapour mixture analyzer/flow meter with new custom electronics allowing ultrasonic frequency transmission through gas mixtures has been developed for this application. Synchronous with the emission of an ultrasound 'chirp' from an acoustic transmitter, a fast readout clock (40 MHz) is started. The clock is stopped on receipt of an above threshold sound pulse at the receiver. Sound is alternately transmitted parallel and anti-parallel with the vapour flow for volume flow measurement from transducers that can serve as acoustic transmitters or receivers. In the development version, continuous real-time measurement of C{sub 3}F{sub 8}/C{sub 2}F{sub 6} flow and calculation of the mixture ratio is performed within a graphical user interface developed in PVSS-II, the Supervisory, Control and Data Acquisition standard chosen for LHC and its experiments at CERN. The described instrument has numerous potential applications - including refrigerant leak detection, the analysis of hydrocarbons, vapour mixtures for semiconductor manufacture and anesthetic gas mixtures. (authors)

  13. Chemistry of the global troposphere - Fluorocarbons as tracers of air motion

    NASA Technical Reports Server (NTRS)

    Prather, Michael; Russell, Gary; Rind, David; Mcelroy, Michael; Wofsy, Steven

    1987-01-01

    Winds and convective mixing from a general circulation model of the atmosphere have been applied in a chemical tracer model (CTM) to simulate the global distribution and temporal variability of chlorofluorocarbons (CFCs). The seasonal cycle in moist convection, with maximum activity over continents in summer, leads to an annual cycle in the surface concentration of CFCs. Emissions are retained in the lowest levels of the atmosphere during winter, and surface concentrations peak near sources. In this season, CFCs from European sources are carried by low-level winds into the Arctic. During summer, vertical exchange is more efficient, and pollutants are transported more rapidly to the middle atmosphere. Consequently, concentrations of CFCs during summer are relatively low near the surface and elevated in the middle troposphere. Time series analysis of data from Adrigole, Ireland, indicates that the model accurately simulates long-range transport of air pollution. The model reproduces global distributions and trends for CFC-11 and CFC-12 observed by the ALE experiment; however, subgrid diffusion must be introduced into the model in order to reproduce the observed interhemispheric gradient. Interhemispheric exchange occurs mainly in the upper tropical troposphere, producing a profile which increases with altitude in the Southern Hemisphere, in agreement with observations. The distribution of CFCs is such that it is necessary to apply important corrections to observations at surface stations in order to derive global distributions.

  14. Restoration of the interfacial properties of lung surfactant with a newly designed hydrocarbon/fluorocarbon lipid.

    PubMed

    Dilli, Gokce; Unsal, Hande; Uslu, Burcin; Aydogan, Nihal

    2014-10-01

    Serum proteins, especially fibrinogen, inactivate the lung surfactant mixture by adsorbing quickly and irreversibly to the alveolar air/aqueous interface. As a consequence of the inactivation, the surfactant becomes dysfunctional, and respiration cannot be maintained properly. Preventing the adsorption of surface active serum proteins to the air/water interface is important because this phenomenon causes fatal diseases such as acute respiratory distress syndrome (ARDS). Although some treatments exist, improvements in synthetic surfactants that can resist this inactivation are still expected. In this context, a novel ion pair lipid (IPL, CF3(CF2)7SO3(-)(CH2CH3)3N(+)(CH2OCH2)10(CH2)15CH3) has been designed and synthesized. This surfactant reduces the inhibitory effect of fibrinogen by selectively interacting with DPPC (dipalmitoylphosphatidylcholine) and mimicking some of the interfacial properties of the pulmonary surfactant protein B (SP-B). Surface pressure-area isotherms and fluorescence microscopy images demonstrate that IPL can mix and interact synergistically with DPPC due to its unique molecular structure. Hysteresis behaviors of the monolayers, which are composed of mixtures of DPPC and IPL at different molar ratios, indicate that with increasing amounts of IPL, the lipid losses from the interface induced by the presence of fibrinogen significantly decrease. It is also found that IPL is able to adsorb to monolayers formed in the presence of fibrinogen, whereas fibrinogen cannot penetrate the monolayers formed in the presence of IPL. These results indicate that by mimicking some of the interfacial properties of SP-B, this novel hybrid molecule is promising in terms of preventing fibrinogen adsorption and therefore resisting surfactant inactivation. PMID:25112907

  15. Comparison of TEWI for fluorocarbon alternative refrigerants and technologies in residential heat pumps and air conditioners

    SciTech Connect

    Sand, J.R.; Fischer, S.K.; Baxter, V.D.

    1999-07-01

    A study was conducted to examine the total equivalent warming impacts (TEWI) of unitary residential and commercial space conditioning equipment in North America, Europe, and Japan using refrigerants R-407C, R-410A, and R-290 and alternative heating/cooling technologies. Assumptions and results of this study are presented for US residential applications. Alternative systems are compared with the TEWI of conventional R-22 based vapor compression systems under the same operating conditions. The analysis for North America includes low- and medium-efficiency electric heat pumps and high-efficiency air-to-air and geothermal heat pumps. Alternative space conditioning technologies, such as electric resistance heat, a gas furnace/central air conditioner combination, a gas engine-driven heat pump, and a prototype gas-fired absorption heat pump, are included for residential TEWI comparisons in three US cities with a range of heating and cooling loads. The effects of improving seasonal efficiencies on TEWI are shown, as well as the consequences of replacing R-22 with alternative refrigerants. TEWI results from previous reports, and those presented here show that the direct global warming potential (GWP) of the refrigerant used for residential heat pump applications contributes less than 7% to the total TEWI for these products and that the direct GWP of the refrigerant is less important than the overall efficiency of the unitary system. Clearly, any refrigerant or refrigerant blend proposed as an alternative for R-22 must provide good cycle efficiency in addition to acceptable environmental and operational qualities to be seriously considered in unitary equipment applications.

  16. New surfactants design for CO2 applications: Molecular dynamics simulations of fluorocarbon-hydrocarbon oligomers

    NASA Astrophysics Data System (ADS)

    Kirmizialtin, Serdal; Menceloglu, Yusuf Z.; Baysal, Canan

    2003-09-01

    Novel block co-oligomers are designed as candidate surfactants in near-supercritical CO2 environment, with the CO2-phobic block consisting of ethyl propionate and ten different types of ethylene monomers, flanked on either side by eight repeat unit fluorinated CO2-philic blocks. Single chain molecular dynamics simulations are performed to understand their conformational and dynamic properties. Depending on the side chain type, the CO2-phobic blocks are prone to shrinkage in the CO2 environment, while the CO2-philic blocks preserve their vacuum dimensions. The overall chains form U-shaped planar structures with flapping motion of the fluorinated arms; thus, we expect bilayer micelle formation under these conditions. The origin of the CO2-oligomer interactions is investigated and van der Waals interactions are found to dominate over electrostatic interactions in the CO2 environment. Calculations of the radial distribution function for the solvent molecules around the oligomer backbone show a solvation shell around 5-6 , irrespective of the oligomer type; density of the solvent around the oligomer, on the other hand, varies with type of side chain due to the interactions between the CO2 molecules and the oligomer, and the available volume around the side chain. The local chain dynamics is investigated by orientational autocorrelation functions, and the characteristic time of the relaxation of selected C-H and C-F bonds is found to depend on the local friction experienced by the fluctuating atoms and the energy barrier that needs to be surmounted during the relaxation process. The simple exponential decay of the correlation functions for the C-H bond is common for all oligomer types, whereas the stretched exponents take on smaller values depending on the side chain for the C-F bond vector, implying that the fluorinated blocks are exposed to more complicated dynamical processes.

  17. Proceedings of the 1993 Non-Fluorocarbon Insulation, Refrigeration and Air Conditioning Technology Workshop

    NASA Astrophysics Data System (ADS)

    Sessions included: HFC blown polyurethanes, carbon dioxide blown foam and extruded polystyrenes, plastic foam insulations, evacuated panel insulation, refrigeration and air conditioning, absorption and adsorption and stirling cycle refrigeration, innovative cooling technologies, and natural refrigerants. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

  18. Nanostructure imaging mass spectrometry: the role of fluorocarbons in metabolite analysis and yoctomole level sensitivity.

    PubMed

    Kurczy, Michael E; Northen, Trent R; Trauger, Sunia A; Siuzdak, Gary

    2015-01-01

    Nanostructure imaging mass spectrometry (NIMS) has become an effective technology for generating ions in the gas phase, providing high sensitivity and imaging capabilities for small molecules, metabolites, drugs, and drug metabolites. Specifically, laser desorption from the nanostructure surfaces results in efficient energy transfer, low background chemical noise, and the nondestructive release of analyte ions into the gas phase. The modification of nanostructured surfaces with fluorous compounds, either covalent or non-covalent, has played an important role in gaining high efficiency/sensitivity by facilitating analyte desorption from the nonadhesive surfaces, and minimizing the amount of laser energy required. In addition, the hydrophobic fluorinated nanostructure surfaces have aided in concentrating deposited samples into fine micrometer-sized spots, a feature that further facilitates efficient desorption/ionization. These fluorous nanostructured surfaces have opened up NIMS to very broad applications including enzyme activity assays and imaging, providing low background, efficient energy transfer, nondestructive analyte ion generation, super-hydrophobic surfaces, and ultra-high detection sensitivity. PMID:25361674

  19. Mixtures of hydrocarbon and fluoro-carbon surfactants in micelles and at phase boundaries

    SciTech Connect

    Pletnev, M.Y.; Frolov, Y.G.; Remizov, Y.V.

    1986-07-01

    A deviation from the additivity of the surface and interphase tension of aqueous solutions of mixtures of sodium lauryl sulfate with the sodium and ammonium salt of perfluoropelargonic acid was found. The antagonism of the surfactants consists of the fact that the critical micelle concentration (CMC) of their mixtures is higher than the CMC of the individual components and in the presence of a critical concentration of demicellization of the surfactants detected in solubilization of the dye. The aqueous films containing the surfactants investigated are stable on the surface of CCl/sub 4/, decrease the rate of its evaporation and promote foaming.

  20. New fluorocarbon elastomers for seals for geothermal and other aggressive environments. Final report

    SciTech Connect

    Lagow, R.J.

    1982-12-01

    Saturated ethyllenic elastomers having a range of methyl group substitution, and a range of partial fluorine substitution were screened. Elastomers based on vinylidene fluoride hexafluoropropylene (VDFHFP) and those based on tetrafluoroethylenepropylene (TFEP) (alternating) were successfully cross-linked by electron-beam radiation and fluorinated to yield elastomeric products, but those based on ethylene-propylene-diene (EPDM) elastomer became brittle after fluorination. The best products were evaluated using tensile strength, elongation at break, solvent swelling, thermogravimetric analysis and infrared. A wide range of carbon-black filled compositions using the TFEP elastomer were cross-linked. The compositions were then fluorinated at or near room temperature for extended periods of time. After fluorination the samples were subjected to geothermal brine at 300/sup 0/C. The best carbon-black filled composition again lasted at least 100 days in the geothermal brine. This filler-elastomer composition was chosen for use in the production of 0-rings. The 0-rings were produced by compression molding using a 30 ton hydraulic press. Various sizes of 0-rings were produced ranging fro 0.8 to 2.0 inches in diameter and from 1/16 to 3/16 inches in width. The final 0-rings were cross-linked at 40 Mrad and fluorinated under the optimized conditions developed for the samples.

  1. Decomposition experiment of hydro-fluorocarbon gas by pulsed TEA CO2 laser

    NASA Astrophysics Data System (ADS)

    Maeno, Kazuo; Udagawa, Shinsuke; Toyada, Kazuhiro

    2005-03-01

    This paper deals with a trial experiment of decomposition of environmental gas R-12 by the pulsed TEA CO2 laser. Nowadays refrigerant R-12 and other hydro-chlorofluorocarbon gases are strongly prohibited to produce, as these gases have both strong ozone-depleting effects and green-house effects. The gases of already produced by huge amount should be decomposed as fast as possible by suitable technical methods. Along with the conventional kiln furnace of cement, arc discharge and the HG discharge are good methods for the freon decomposition. Both methods, however, have the weakness of electrode damages (arcing) or low-pressure operation (HF discharge). High power CO2 laser seems to have good properties for such decomposition with favorable wavelength for the absorption. In our small-scale experiment of gas decomposition a pulsed TEA CO2 laser of several joules is utilized to produce the plasma in R-12 flow channel of glass tube. The withdrawal of decomposed gases is performed by Ca alkalized water. The deposit mass is measured, and powder X-ray diffraction measurement is carried out on the deposit powder. The possibility of our laser gas decomposition is discussed.

  2. Fluorocarbon liner protected with chemical resistant masonry solves tough corrosion problem

    SciTech Connect

    Heffner, D.

    1997-02-01

    At a major pigment manufacturer`s plant, a kiln produces SO{sub 2}-SO{sub 3} process gas containing 90% SO{sub 2} used in sulfuric acid production. The towers where the sulfuric acid is produced follow an intermediate stage in the production of iron-based pigments. The lead-lined towers that had lasted more than five years began to leak after two years. Once the liner develops a pinhole leak, acid eats through the carbon steel substrate within a few days. A composite membrane was selected consisting of PVDF resin reinforced with woven cloth for improved physical properties. This was applied over the entire surface of the scrubber tower, including inlets, outlets, and metal flanges. The laminate was applied by a multi-coat wet lay-up process to a nominal thickness of 40 mil (1 mm), oven baked after each coat.

  3. Block copolymer-like self-assembly of fluorocarbon end-functionalized polystyrene and polybutylmethacrylate.

    PubMed

    Shen, Jingguo; Hogen-Esch, Thieo

    2008-08-20

    We demonstrate the self-assembly through fluorophilic interactions of a blend of perfluorocarbon (RF) end-functionalized polystyrene and the corresponding RF-polybutylmethacrylate into optically transparent materials that retain domain characteristics typical of the component polymers but show well-defined lamellar nanostructured morphologies that qualitatively resemble that of the corresponding block copolymers. PMID:18646751

  4. An assessment of potential impact of alternative fluorocarbons on tropospheric ozone

    NASA Technical Reports Server (NTRS)

    Niki, Hiromi

    1990-01-01

    While the chlorofuorocarbons (CFCs) such as CFC-11 (CFCl3) and CFC-12 (CF2Cl2) are chemically inert in the troposphere, the hydrogen-containing halocarbons being considered as their replacements can, to a large extent, be removed in the troposphere by the HO radical. These alternative halocarbons include the hydrochlorofluorocarbons (HCFCs) 123 (CF3CHCl2), 141b (CFCl2CH3), 142b (CF2ClCH3), 22 (CHF2Cl), and 124 (CF3CHFCl) and the hydrofluorocarbons (HCFs) 134a (CF3CH2F), 152a (CHF2CH3) and 125 (CF3CHF2). Listed are the rate constants (k) for the HO radical reaction of these compounds and their estimated chemical lifetimes in the troposphere. In this table, values of the lifetimes of these selected HCFCs and HCFs are seen to vary by more than a factor of more than ten ranging from 1.6 years for HFC 152a and HCFC 125 to as long as 28 years for HFC 125. Clearly, from the standpoint of avoiding or minimizing impact on stratospheric O3, those halocarbons with short tropospheric lifetimes are the desirable alternates. However, potential environmental consequences of their degradation in the troposphere should be assessed and taken into account in the selection process.

  5. Proceedings of the 1993 non-fluorocarbon insulation, refrigeration and air conditioning technology workshop

    SciTech Connect

    Not Available

    1994-09-01

    Sessions included: HFC blown polyurethanes, carbon dioxide blown foam and extruded polystyrenes, plastic foam insulations, evacuated panel insulation, refrigeration and air conditioning, absorption and adsorption and stirling cycle refrigeration, innovative cooling technologies, and natural refrigerants. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

  6. Atmospheric measurements of CF/sub 4/ and other fluorocarbons containing the CF/sub 3/ grouping

    SciTech Connect

    Penkett, S.A.; Prosser, N.J.D.; Rasmussen, R.A.; Khalil, M.A.K.

    1981-06-20

    Careful measurements by GC/MS techniques on atmospheric carbon tetrafluoride confirm that its concentration in 1979 was constant at about 69.9 pptv (standard deviation is 7.2 pptv). It is almost certainly produced entirely by emissions from the aluminum industry. Other compounds in the atmosphere containing the CF/sub 3/ group have been identified by GC/MS as C/sub 2/F/sub 6/, CF/sub 3/CL, CF/sub 3/Br,and C/sub 2/F/sub 5/CL. The concentrations of the first pair are about 4 pptv, and the latter two are about 0.7 pptv and 4 pptv, respectively. The C/sub 2/F/sub 6/ is produced simultaneously with CF/sub 4/ in the manufacture of aluminum. CF/sub 3/Cl, CF/sub 3/Br, and C/sub 2/F/sub 5/Cl are probably produced by the chemical industry. The environmental importance of these compounds is discussed in the context of two papers on CF/sub 4/ recently published by Cicerone (1979) and by Wang et al. (1980).

  7. Effects of water-soluble spacers on the hydrophobic association of fluorocarbon-modified poly(acrylamide)

    SciTech Connect

    Hwang, F.S.; Hogen-Esch, T.E.

    1995-04-24

    A number of acrylamide-acrylate copolymers were synthesized in which the acrylate (CH{sub 2}{double_bond}CHCOO(CH{sub 2}CH{sub 2}O){sub n}R) is hydrophobic on account of the presence of a 1,1-dihydroperfluorooctyl group or a dodecyl group connected to the acrylate via a {minus}(CH{sub 2}CH{sub 2}O){sub n} hydrophilic spacer (n = 0--3). Copolymerization of these monomers was initiated by sodium metabisulfite and ammonium persulfate at 60 C in aqueous media in the presence of surfactants and acetone. The low shear viscosities of 0.5 wt % solutions of these copolymers as a function of comonomer molar content gave bell-shaped curves having maxima at 0.10--0.60 mol % comonomer, consistent with competitive inter- and intramolecular hydrophobic association. The copolymers having perfluorocarbon pendent groups gave higher viscosities at lower comonomer content. Furthermore, for both the hydrocarbon- and perfluorocarbon-containing copolymers the viscosities increased, and the comonomer content at the viscosity maximum decreased, with increasing spacer length. The increased effectiveness of the longer spacers is attributed to entropy effects in the formation of polymer assemblies.

  8. Surface patterning using plasma-deposited fluorocarbon thin films for single-cell positioning and neural circuit arrangement.

    PubMed

    Leclair, Amanda M; Ferguson, Stephen S G; Lagugn-Labarthet, Franois

    2011-02-01

    Micropatterning glass substrates with a plasma-deposited fluoropolymer thin film was shown to be an efficient approach to manipulate cell positioning. The glass windows promoted cell adhesion, whereas the surrounding fluoropolymer displays a cell-repelling character. Herein, multiple micropatterned substrates were developed with pattern dimensions sufficient to host solely single-cells. These single-cell arrays would allow analysis of individual cell response to stimulation without interference from cell-cell interactions. Mouse myoblast C2C12 cells and cortical neurons from mice were examined, both for amenability to patterning, as well as success of cell adhesion and cell morphology. Both cell types were found to have optimal adherence and growth on the glass surface, while cell adhesion and function was inhibited on the fluoropolymer. The C2C12 cells conformed to the shape of the pattern, while maintaining a healthy structure. Moreover, the neuron cells followed the hexagonal grid patterns and formed circuits, wherein the complexity of the connections depended on incubation time. PMID:21074849

  9. Post-Flight Analysis of Selected Fluorocarbon and Other Thin Film Polymer Specimens Flown on MISSE-5

    NASA Technical Reports Server (NTRS)

    DeGroh, Kim; Finckenor, Miria; Minton, Tim; Brunsvold, Amy; Pippin, Gary

    2007-01-01

    Twenty thin film specimens were flown on M1SSE-5 as a cooperative effort between several organizations. This presentation will report results of initial inspections and post-flight measurements of the optical properties and recession of these materials due to the approx.13 month exposure period on the exterior of the International Space Station. These specimens were located on the "anti-solar" side of the MISSE-5 container and received a low number of Equivalent Sun Hours of solar UV exposure. Profilometry and/or ATF measurements will be conducted to determine thickness changes and atomic oxygen-induced recession rates Six of the specimens were covered with thin Kapton films, 0.1 and 0.3 mil in thickness. The 0.1 mil Kapton was almost completely eroded, suggesting that the atomic oxygen fluence is <8 x 10(exp 19) atoms/sq cm, similar to levels experienced during Space Shuttle materials experiments in the 1980's and 1990's. A comparison of results from MISSE-5 and Space Shuttle experiments will be included for those materials common to both the short and long-term exposures.

  10. Estimation of Flammability Limits of Selected Fluorocarbons with F(sub 2) and CIF(sub3)

    SciTech Connect

    Trowbridge, L.D.

    1999-09-01

    During gaseous diffusion plant operations, conditions leading to the formation of flammable gas mixtures may occasionally arise. Currently, these could consist of the evaporative coolant CFC-114 and fluorinating agents such as F(sub 2) and CIF(sub 3). Replacement of CFC-114 with non-ozone-depleting substitutes such as c-C(sub 4)F(sub 8) and C(sub 4)F(sub 10) is planned. Consequently, in the future, these too must be considered potential ''fuels'' in flammable gas mixtures. Two questions of practical interest arise: (1) can a particular mixture sustain and propagate a flame if ignited, and (2) what is the maximum pressure that can be generated by the burning (and possibly exploding) gas mixture, should ignite? Experimental data on these systems are limited. To assist in answering these questions, a literature search for relevant data was conducted, and mathematical models were developed to serve as tools for predicting potential detonation pressures and estimating (based on empirical correlations between gas mixture thermodynamics and flammability for known systems) the composition limits of flammability for these systems. The models described and documented in this report are enhanced versions of similar models developed in 1992.

  11. Self-organization of mixtures of fluorocarbon and hydrocarbon amphiphilic thiolates on the surface of gold nanoparticles.

    PubMed

    Posocco, Paola; Gentilini, Cristina; Bidoggia, Silvia; Pace, Alice; Franchi, Paola; Lucarini, Marco; Fermeglia, Maurizio; Pricl, Sabrina; Pasquato, Lucia

    2012-08-28

    Self-assembled monolayers composed of a mixture of thiolate molecules, featuring hydrocarbon or perfluorocarbon chains (H- and F-chains) terminating with a short poly(oxoethylene) (PEG) moiety, are the most extreme example of surfactant immiscibility on gold nanoparticles reported so far. The phase segregation between H-chains and F-chains and the consequent, peculiar folding of PEG chains are responsible for the increased affinity of a selected radical probe for the fluorinated region, which increases as the size of the fluorinated domains decrease, independently of the shape of such domains. This feature has been revealed by ESR measurements and an in silico innovative multiscale molecular simulations approach in explicit water. Our results reveal an underlying mechanism of a transmission of the organization of the monolayer from the inner region close to the gold surface toward the external hydrophilic PEG region. Moreover, this study definitively proves that a mixed monolayer is a complex system with properties markedly different from those characterizing the parent homoligand monolayers. PMID:22804477

  12. Development of atmospheric characteristics of chlorine-free alternative fluorocarbons. Report on R-134a and E-143a

    SciTech Connect

    Orkin, V.L.; Khamaganov, V.G.; Guschin, A.G.; Kasimovskaya, E.E.; Larin, I.K.

    1993-04-01

    Rate constants have been measured for the gas phase reaction of OH radicals with 1,1,1,2-tetrafluoroethane R-134a (CH{sub 2}F-CF{sub 3}) and methyl trifluoromethyl ether E-143a (CH{sub 3}-O-CF{sub 3}) over the temperature range 298--460 K. Arrhenius expressions were derived for atmospheric modeling. The infrared absorption cross-sections for R-134a and E-143a have been measured in the region from 400 to 1600 cm{sup {minus}1} and the integrated band strengths have been calculated. The atmospheric lifetimes R-134a and E-143a have been estimated to be 11.6 years and 4.1 years respectively. Global warming potentials have been estimated over time horizons of 20, 50, 100, 200, and 500 years.

  13. Nanostructure Imaging Mass Spectrometry: The Role of Fluorocarbons in Metabolite Analysis and the Road to Yoctomole Level Sensitivity

    PubMed Central

    Kurczy, Michael E.; Northen, Trent R.; Trauger, Sunia A.; Siuzdak, Gary

    2016-01-01

    Nanostructure Imaging mass spectrometry (NIMS) has become an effective technology for generating ions in the gas phase, providing high sensitivity and imaging capabilities on small molecules, metabolites, drugs, and drug metabolites. Specifically, laser desorption from the nanostructure surfaces results in efficient energy transfer, low background chemical noise, and the nondestructive release of analyte ions into the gas phase. The modification of nanostructured surfaces with fluorous compounds, either covalent or non-covalent, has played an important role in gaining high efficiency/sensitivity by facilitating analyte desorption from the non-adhesive surfaces, and minimizing the amount of laser energy required. In addition, the hydrophobic fluorinated nanostructure surfaces have aided in concentrating deposited samples into fine micrometer sized spots, a feature that further facilitates efficient desorption/ionization. These fluorous nanostructured surfaces have opened up NIMS to very broad applications including enzyme activity assays and imaging, providing low background, efficient energy transfer, nondestructive analyte ion generation, super-hydrophobic surfaces, and ultra-high detection sensitivity. PMID:25361674

  14. An assessment of potential degradation products in the gas-phase reactions of alternative fluorocarbons in the troposphere

    NASA Technical Reports Server (NTRS)

    Niki, Hiromi

    1990-01-01

    Tropospheric chemical transformations of alternative hydrofluorocarbons (HCF's) and hydrochlorofluorocarbons (HCFC's) are governed by hydroxyl radical initiated oxidation processes, which are likely to be analogous to those known for alkanes and chloroalkanes. A schematic diagram is used to illustrate plausible reaction mechanisms for their atmospheric degradation, where R, R', and R'' denote the F- and/or Cl-substituted alkyl groups derived from HCF's and HCFC's subsequent th the initial H atom abstraction by HO radicals. At present, virtually no kinetic data exist for the majority of these reactions, particularly for those involving RO. Potential degradation intermediates and final products include a large variety of fluorine- and/or chlorine-containing carbonyls, acids, peroxy acids, alcohols, hydrogen peroxides, nitrates and peroxy nitrates, as summarized in the attached table. Probably atmospheric lifetimes of these compounds were also estimated. For some carbonyl and nitrate products shown in this table, there seem to be no significant gas-phase removal mechanisms. Further chemical kinetics and photochemical data are needed to quantitatively assess the atmospheric fate of HCF's and HCFC's, and of the degradation products postulated in this report.

  15. Tropospheric reactions of the haloalkyl radicals formed from hydroxyl radical reaction with a series of alternative fluorocarbons

    NASA Technical Reports Server (NTRS)

    Atkinson, Roger

    1990-01-01

    In the present assessment, the hydrogen containing halocarbons being considered as alternatives to the the presently used chlorofluorocarbons are the hydrochlorofluorocarbons (HCFCs) 123 (CF3CHCl2), 141b (CFCl2CH3), 142b (CF2ClCH3), 22 (CHF2Cl) and 124 (CF3CHFCl) and the hydrofluorocarbons (HFCs) 134a (CF3CH2F), 152a (CHF2CH3) and 125 (CF3CHF2). All of these HCFCs and HFCs will react with the hydroxyl (OH) radical in the troposphere, giving rise to haloalkyl radicals which then undergo a complex series of reactions in the troposphere. These reactions of the haloalkyl radicals formed from the initial OH radical reactions with the HCFCs and HFCs under tropospheric conditions are the focus here.

  16. ESCA study of several fluorocarbon polymers exposed to atomic oxygen in low earth orbit or within or downstream from a radio-frequency oxygen plasma

    NASA Technical Reports Server (NTRS)

    Golub, Morton A.; Wydeven, Theodore; Cormia, Robert D.

    1989-01-01

    The ESCA (electron spectroscopy for chemical analysis) spectra of films of Tedlar, tetrafluoroethylene-hexafluoropropylene copolymer (in the form of a Teflon FEP coating on Kapton H, i.e., Kapton F), and polytetrafluoroethylene (Teflon or Teflon TFE), exposed to atomic oxygen O(3P) either in LEO on the STS-8 Space Shuttle or within or downstream from a radio-frequency oxygen plasma, were compared. The major difference in surface chemistry of Tedlar induced by the various exposures to O(3P) was a much larger uptake of oxygen when etched either in or out of the glow of an O2 plasma than when etched in LEO. In contrast, Kapton F exhibited very little surface oxidation during any of the three different exposures to O(3P), while Teflon was scarcely oxidized.

  17. Effect of fluorocarbon self-assembled monolayer films on sidewall adhesion and friction of surface micromachines with impacting and sliding contact interfaces

    SciTech Connect

    Xiang, H.; Komvopoulos, K.

    2013-06-14

    A self-assembled monolayer film consisting of fluoro-octyltrichlorosilane (FOTS) was vapor-phase deposited on Si(100) substrates and polycrystalline silicon (polysilicon) surface micromachines. The hydrophobic behavior and structural composition of the FOTS film deposited on Si(100) were investigated by goniometry and X-ray photoelectron spectroscopy, respectively. The effects of contact pressure, relative humidity, temperature, and impact/sliding cycles on the adhesive and friction behavior of uncoated and FOTS-coated polysilicon micromachines (referred to as the Si and FOTS/Si micromachines, respectively) were investigated under controlled loading and environmental conditions. FOTS/Si micromachines demonstrated much lower and stable adhesion than Si micromachines due to the highly hydrophobic and conformal FOTS film. Contrary to Si micromachines, sidewall adhesion of FOTS/Si micromachines demonstrated a weak dependence on relative humidity, temperature, and impact cycles. In addition, FOTS/Si micromachines showed low and stable adhesion and low static friction for significantly more sliding cycles than Si micromachines. The adhesive and static friction characteristics of Si and FOTS/Si micromachines are interpreted in the context of physicochemical surface changes, resulting in the increase of the real area of contact and a hydrophobic-to-hydrophilic transition of the surface chemical characteristics caused by nanoscale surface smoothening and the removal of the organic residue (Si micromachines) or the FOTS film (FOTS/Si micromachines) during repetitive impact and oscillatory sliding of the sidewall surfaces.

  18. Semiempirical molecular orbital calculations of anisotropic 1H, 13C and 19F hyperfine coupling constants in hydrocarbon and fluorocarbon radicals

    NASA Astrophysics Data System (ADS)

    Barfield, Michael; Babaqi, Abdulla S.; Doddrell, David M.; Gottlieb, Hans P. W.

    The anisotropic hyperfine coupling constants (AHCC) from the electron spin resonance (E.S.R.) spectra of a variety of atoms in organic radicals have been calculated by means of semiempirical molecular orbital wavefunctions in the INDO approximation. Hyperfine tensors involving 1H, 13C and 19F nuclei are obtained for the ĊH, ĊH3, CH3ĊH2, (CH3)3Ċ hydrocarbon radicals, malonic acid radical, ĊH2F, ĊF2H, ĊF3 and CF3ĊH2 radicals. The calculated values are compared with available experimental, non-empirical and semiempirical values for these radicals. All integrals of the operator entering the electronic contributions have been evaluated over Slater type orbitals. The introduction of deorthogonalized wavefunctions gives generally better calculated results. In particular, the tensor components of the 19F AHCC are in good agreement with the experimental results without the necessity of readjusting the effective nuclear charges.

  19. Effect of Low-frequency Power on F, CF2 Relative Density and F/CF2 Ratio in Fluorocarbon Dual-Frequency Plasmas

    NASA Astrophysics Data System (ADS)

    Huang, Hongwei; Ye, Chao; Xu, Yijun; Yuan, Yuan; Shi, Guofeng; Ning, Zhaoyuan

    2010-10-01

    Effect of low-frequency power on F, CF2 relative density and F/CF2 ratio, in C2F6, C4F8 and CHF3 dual-frequency capacitively couple discharge driven by the power of 13.56 MHz/2 MHz, was investigated by using optical emission spectroscopy. High F, CF2 relative density and high F/CF2 ratio were obtained in a CHF3 plasma. But for C2F6 and C4F8 plasmas, the F, CF2 relative density and F/CF2 ratio all decreased significantly due to the difference in both reactive paths and reactive energy. The increase of LF power caused simultaneous increase of F and CF2 radical relative densities in C4F8 and CHF3 plasmas, but led to increase of F with the decrease in CF2 relative densities in C2F6 plasma due to the increase of lower energy electrons and the decrease of higher energy electrons in electron energy distribution function (EEDF).

  20. Fluorocarbon Contamination from the Drill on the Mars Science Laboratory: Potential Science Impact on Detecting Martian Organics by Sample Analysis at Mars (SAM)

    NASA Technical Reports Server (NTRS)

    Eigenbrode, J. L.; McAdam, A.; Franz, H.; Freissinet, C.; Bower, H.; Floyd, M.; Conrad, P.; Mahaffy, P.; Feldman, J.; Hurowitz, J.; Evans, J.; Anderson, M.; Jandura, L.; Brown, K.; Logan, C.; Kuhn, S.; Anderson, R.; Beegle, L.; Limonadi, D.; Rainen, R.; Umland, J.

    2013-01-01

    Polytetrafluoroethylene (PTFE or trade name: Teflon by Dupont Co.) has been detected in rocks drilled during terrestrial testing of the Mars Science Laboratory (MSL) drilling hardware. The PTFE in sediments is a wear product of the seals used in the Drill Bit Assemblies (DBAs). It is expected that the drill assembly on the MSL flight model will also shed Teflon particles into drilled samples. One of the primary goals of the Sample Analysis at Mars (SAM) instrument suite on MSL is to test for the presence of martian organics in samples. Complications introduced by the potential presence of PTFE in drilled samples to the SAM evolved gas analysis (EGA or pyrolysisquadrupole mass spectrometry, pyr-QMS) and pyrolysis- gas chromatography mass spectrometry (Pyr- GCMS) experiments was investigated.

  1. The Influence of Fluorocarbon and Hydrocarbon Acyl Groups at the Surface of Bovine Carbonic Anhydrase II on the Kinetics of Denaturation by Sodium Dodecyl Sulfate

    PubMed Central

    Lee, Andrew; Mirica, Katherine A.; Whitesides, George M.

    2011-01-01

    This paper examines the influence of acylation of the Lys-ε-NH3+ groups of bovine carbonic anhydrase (BCA, E.C. 4.2.1.1) to Lys-ε-NHCOR (R = -CH3, -CH2CH3, and -CH(CH3)2, -CF3) on the rate of denaturation of this protein in buffer containing sodium dodecyl sulfate (SDS). Analysis of the rates suggested separate effects due to electrostatic charge and hydrophobic interactions. Rates of denaturation (kAc,n) of each series of acylated derivatives depended on the number of acylations (n). Plots of log kAc,n vs. n followed U-shaped curves. Within each series of derivatives, rates of denaturation decreased as n increased to ~7; this decrease was compatible with increasingly unfavorable electrostatic interactions between SDS and protein. In this range of n, rates of denaturation also depended on the choice of the acyl group as n increased to ~7, in a manner compatible with favorable hydrophobic interactions between SDS and the -NHCOR groups. As n increased in the range 7 < n < 14 however, rates of denaturation stayed approximately constant; analysis suggested these rates were compatible with an increasingly important contribution to denaturation that depended both on the net negative charge of the protein and on the hydrophobicity of the R group. The mechanism of denaturation thus seems to change with the extent of acylation of the protein. For derivatives with the same net electrostatic charge, rates of denaturation increased with the acyl group (by a factor of ~3 for n ~ 14) in the order CH3CONH- < CH3CH2CONH- < (CH3)2CHCONH- < CF3CONH-. These results suggested that the hydrophobicity of CF3CONH- is slightly greater (by a factor of < 2) than that of RHCONH- similar in surface area. PMID:21182314

  2. Surface kinetics modeling of silicon and silicon oxide plasma etching. III. Modeling of silicon oxide etching in fluorocarbon chemistry using translating mixed-layer representation

    SciTech Connect

    Kwon, Ohseung; Bai Bo; Sawin, Herbert H.

    2006-09-15

    Silicon oxide etching was modeled using a translating mixed-layer model, a novel surface kinetic modeling technique, and the model showed good agreement with measured data. Carbon and fluorine were identified as the primary contributors to deposition and etching, respectively. Atomic fluorine flux is a major factor that determines the etching behavior. With a chemistry having a small amount of atomic fluorine (such as the C{sub 4}F{sub 8} chemistry), etching yield shows stronger dependence on the composition change in the gas flux.

  3. Growth of fluorocarbon macromolecules in the gas phase: IV. Li+-attachment mass spectrometric investigation of high-mass neutral radicals in the downstream region of Ar/c-C4F8 plasmas

    NASA Astrophysics Data System (ADS)

    Okumura, Hiroshi; Furuya, Kenji; Harata, Akira

    2009-03-01

    Mass analysis has been conducted on neutral species in the downstream region of Ar/c-C4F8 plasmas by Li+-attachment mass spectrometry. Various peaks appeared in the mass spectrum observed in the case of 29% c-C4F8, and many of them have unambiguously been assigned to the Li+ adducts of neutral radicals with odd-numbered fluorine atoms from 2n + 1 to 2n - 5, where n means the number of carbon atoms, as well as neutral species with even-numbered fluorine atoms from 2n + 2 to 2n - 10. In contrast, only the peaks due to CnF2n+2 (n = 1-7), CnF2n (n = 1, 4-8), CnF2n-2 (n = 3, 5-8) and C9F14 appeared in the case of 2.2% c-C4F8. These findings demonstrate that the Li+-attachment ionization is fragment-free, not only for relatively stable perfluorocarbon species but also for their neutral radicals, and therefore effective for the identification of high-mass neutral perfluorocarbon radicals. The analysis of the growth mechanisms of CnF2n+2 and CnF2n on the basis of thermochemistry has proposed CF3CF as an important reactant.

  4. Process for the separation of components from gas mixtures

    DOEpatents

    Merriman, J.R.; Pashley, J.H.; Stephenson, M.J.; Dunthorn, D.I.

    1973-10-01

    A process for the removal, from gaseous mixtures of a desired component selected from oxygen, iodine, methyl iodide, and lower oxides of carbon, nitrogen, and sulfur is described. The gaseous mixture is contacted with a liquid fluorocarbon in an absorption zone maintained at superatmospheric pressure to preferentially absorb the desired component in the fluorocarbon. Unabsorbed constituents of the gaseous mixture are withdrawn from the absorption zone. Liquid fluorocarbon enriched in the desired component is withdrawn separately from the zone, following which the desired component is recovered from the fluorocarbon absorbent. (Official Gazette)

  5. Development of a special purpose spacecraft coating, phase 4

    NASA Technical Reports Server (NTRS)

    Gillman, H. D.

    1980-01-01

    Coating formulations based on a fluorocarbon resin were evaluated for use on spacecraft exteriors. Formulations modified with an acrylic resin were found to have excellent offgassing properties. A much less expensive process for increasing to solid content of the fluorocarbon latex was developed.

  6. Utilization of oxygen difluoride for syntheses of fluoropolymers

    NASA Technical Reports Server (NTRS)

    Toy, M. S. (Inventor)

    1976-01-01

    The reaction oxygen difluoride, OF2, with ethylenically unsaturated fluorocarbon compounds is examined. Depending upon the fluorocarbon material and reaction conditions, OF2 can chain extend fluoropolyenes, convert functional perfluorovinyl groups to acyl fluoride and/or epoxide groups, and act as a monomer for an addition type copolymerization with diolefins.

  7. High performance rolling element bearing

    NASA Technical Reports Server (NTRS)

    Bursey, Jr., Roger W. (Inventor); Olinger, Jr., John B. (Inventor); Owen, Samuel S. (Inventor); Poole, William E. (Inventor); Haluck, David A. (Inventor)

    1993-01-01

    A high performance rolling element bearing (5) which is particularly suitable for use in a cryogenically cooled environment, comprises a composite cage (45) formed from glass fibers disposed in a solid lubricant matrix of a fluorocarbon polymer. The cage includes inserts (50) formed from a mixture of a soft metal and a solid lubricant such as a fluorocarbon polymer.

  8. Method of bonding diamonds in a matrix and articles thus produced

    DOEpatents

    Taylor, G.W.

    1981-01-27

    By fluorinating diamond grit, the grit may be readily bonded into a fluorocarbon resin matrix. The matrix is formed by simple hot pressing techniques. Diamond grinding wheels may advantageously be manufactured using such a matrix. Teflon fluorocarbon resins are particularly well suited for using in forming the matrix.

  9. Reciprocating down-hole sand pump

    SciTech Connect

    Ruhle, J.L.

    1987-04-28

    This patent describes the invention of a continuously-operated reciprocating down-hole sand pump comprising: a steel polished plunger pipe that strokes back and forth within a steel honed pump barrel, and is equipped with a self-lubricating fluorocarbon V-ring system that is pressure-actuated during compression strokes; the self-lubricating fluorocarbon V-ring system also is self-actuated by means of coil springs to provide wiping action to the polished plunger pipe during suction strokes; the self-lubricating fluorocarbons V-ring system also self-adjusts by means of coil springs located adjacent the fluorocarbon V-ring so as to automatically compensate for V-ring wear; and the self-lubricating fluorocarbon V-ring system also is designed in such a manner so as to eliminate voids and discourage the extrusion of V-rings in high temperature and high-pressure applications.

  10. Texturing polymer surfaces by transfer casting. [cardiovascular prosthesis

    NASA Technical Reports Server (NTRS)

    Banks, B. A.; Weigand, A. J.; Sovey, J. S. (Inventor)

    1982-01-01

    A technique for fabricating textured surfaces on polymers without altering their surface chemistries is described. A surface of a fluorocarbon polymer is exposed to a beam of ions to texture it. The polymer which is to be surface-roughened is then cast over the textured surface of the fluorocarbon polymer. After curing, the cast polymer is peeled off the textured fluorocarbon polymer, and the peeled off surface has negative replica of the textured surface. The microscopic surface texture provides large surface areas for adhesive bonding. In cardiovascular prosthesis applications the surfaces are relied on for the development of a thin adherent well nourished thrombus.

  11. Flame-resistant textiles

    NASA Technical Reports Server (NTRS)

    Fogg, L. C.; Stringham, R. S.; Toy, M. S.

    1980-01-01

    Flame resistance treatment for acid resistant polyamide fibers involving photoaddition of fluorocarbons to surface has been scaled up to treat 10 yards of commercial width (41 in.) fabric. Process may be applicable to other low cost polyamides, polyesters, and textiles.

  12. HYDRAULIC STUDIES AND CLEANING EVALUATIONS OF ULTRAVIOLET DISINFECTION UNITS

    EPA Science Inventory

    Various types of operating ultraviolet disinfection reactor designs were evaluated for hydraulic characteristics and cleaning requirements. The fluorocarbon polymer tube designs promote plug-flow behavior because of their relatively high length-to-diameter ratio. Hydraulic evalua...

  13. Superhydrophobic lignocellulosic wood fiber/mineral networks.

    PubMed

    Mirvakili, Mehr Negar; Hatzikiriakos, Savvas G; Englezos, Peter

    2013-09-25

    Lignocellulosic wood fibers and mineral fillers (calcium carbonate, talc, or clay) were used to prepare paper samples (handsheets), which were then subjected to a fluorocarbon plasma treatment. The plasma treatment was performed in two steps: first using oxygen plasma to create nanoscale roughness on the surface of the handsheet, and second fluorocarbon deposition plasma to add a layer of low surface energy material. The wetting behavior of the resulting fiber/mineral network (handsheet) was determined. It was found the samples that were subjected to oxygen plasma etching prior to fluorocarbon deposition exhibit superhydrophobicity with low contact angle hysteresis. On the other hand, those that were only treated by fluorocarbon plasma resulted in "sticky" hydrophobicity behavior. Moreover, as the mineral content in the handsheet increases, the hydrophobicity after plasma treatment decreases. Finally, it was found that although the plasma-treated handsheets show excellent water repellency they are not good water vapor barriers. PMID:23957774

  14. Comprehensive bioimaging with fluorinated nanoparticles using breathable liquids

    NASA Astrophysics Data System (ADS)

    Kurczy, Michael E.; Zhu, Zheng-Jiang; Ivanisevic, Julijana; Schuyler, Adam M.; Lalwani, Kush; Santidrian, Antonio F.; David, John M.; Giddabasappa, Anand; Roberts, Amanda J.; Olivos, Hernando J.; O'Brien, Peter J.; Franco, Lauren; Fields, Matthew W.; Paris, Liliana P.; Friedlander, Martin; Johnson, Caroline H.; Epstein, Adrian A.; Gendelman, Howard E.; Wood, Malcolm R.; Felding, Brunhilde H.; Patti, Gary J.; Spilker, Mary E.; Siuzdak, Gary

    2015-01-01

    Fluorocarbons are lipophobic and non-polar molecules that exhibit remarkable biocompatibility, with applications in liquid ventilation and synthetic blood. The unique properties of these compounds have also enabled mass spectrometry imaging of tissues where the fluorocarbons act as a Teflon-like coating for nanostructured surfaces to assist in desorption/ionization. Here we report fluorinated gold nanoparticles (f-AuNPs) designed to facilitate nanostructure imaging mass spectrometry. Irradiation of f-AuNPs results in the release of the fluorocarbon ligands providing a driving force for analyte desorption. The f-AuNPs allow for the mass spectrometry analysis of both lipophilic and polar (central carbon) metabolites. An important property of AuNPs is that they also act as contrast agents for X-ray microtomography and electron microscopy, a feature we have exploited by infusing f-AuNPs into tissue via fluorocarbon liquids to facilitate multimodal (molecular and anatomical) imaging.

  15. 16 CFR 423.1 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... uses any common organic solvent (e.g. petroleum, perchlorethylene, fluorocarbon). The process may also... by which soil is removed from products in a specially designed machine using water, detergent or...

  16. Comprehensive Bio-Imaging with Fluorinated Nanoparticles Using Breathable Liquids

    PubMed Central

    Kurczy, Michael E.; Zhu, Zheng Jiang; Ivanisevic, Julijana; Schuyler, Adam M.; Lalwani, Kush; Santidrian, Antonio F.; David, John W.; Giddabasappa, Anand; Roberts, Amanda; Olivos, Hernando J.; O'Brien, Peter J.; Franco, Lauren; Fields, Matthew W.; Paris, Liliana P.; Friedlander, Martin; Johnson, Caroline H.; Epstein, Adrian; Gendleman, Howard E.; Wood, Malcolm; Felding-Habermann, Brunhilde; Patti, Gary J.; Spilker, Mary E.; Siuzdak, Gary

    2015-01-01

    Fluorocarbons are lipophobic and non-polar molecules that exhibit remarkable bio-compatibility, with applications in liquid ventilation and synthetic blood. The unique properties of these compounds have also enabled mass spectrometry imaging of tissues where the fluorocarbons act as a Teflon-like coating for nanostructured surfaces to assist in desorption/ionization. Here we report fluorinated gold nanoparticles (f-AuNPs) designed to facilitate nanostructure imaging mass spectrometry. Irradiation of f-AuNPs results in the release of the fluorocarbon ligands providing a driving force for analyte desorption. The f-AuNPs allow for the mass spectrometry analysis of both lipophilic and polar (central carbon) metabolites. An important property of AuNPs is that they also act as contrast agents for X-ray microtomography and electron microscopy, a feature we have exploited by infusing f-AuNPs into tissue via fluorocarbon liquids to facilitate multi-modal (molecular and anatomical) imaging. PMID:25601659

  17. Earth's Endangered Ozone

    ERIC Educational Resources Information Center

    Panofsky, Hans A.

    1978-01-01

    Included are (1) a discussion of ozone chemistry; (2) the effects of nitrogen fertilizers, fluorocarbons, and high level aircraft on the ozone layer; and (3) the possible results of a decreasing ozone layer. (MR)

  18. Thermally resistant polymers for fuel tank sealants

    NASA Technical Reports Server (NTRS)

    Webster, J. A.

    1972-01-01

    Conversion of fluorocarbon dicarboxylic acid to intermediates whose terminal functional groups permit polymerization is discussed. Resulting polymers are used as fuel tank sealers for jet fuels at elevated temperatures. Stability and fuel resistance of the prototype polymers is explained.

  19. SUMMARY REVIEW OF HEALTH EFFECTS ASSOCIATED WITH HYDROGEN FLUORIDE AND RELATED COMPOUNDS: HEALTH ISSUE ASSESSMENT

    EPA Science Inventory

    The major natural sources of airborne hydrogen fluoride (HF) are volcanic activity, ocean spray, and crustal weathering of fluoride-containing rocks. Anthropogenic sources include emissions from industrial operations such as aluminum and fluorocarbon production, and uranium proce...

  20. Search for plutonium-244 tracks in mountain pass bastnaesite

    USGS Publications Warehouse

    Fleischer, R.L.; Naeser, C.W.

    1972-01-01

    WE have found that bastnaesite, a rare earth fluorocarbonate, from the Precambrian Mountain Pass deposit has an apparent Cretaceous fission track age, and hence does not reveal any anomalous fission tracks due to 244Pu. ?? 1972 Nature Publishing Group.

  1. Atmospheric trace gas measurements with a new clean air sampling system

    SciTech Connect

    Leifer, R.; Sommers, K.; Guggenheim, S.F.

    1981-10-01

    The development of a new clean air sampling system for the Department of Energy's WB-57F aircraft has allowed the analysis of CCl/sub 3/F (Fluorocarbon-11), CCl/sub 2/F/sub 2/ (Fluorocarbon-12), CHClF/sub 2/ (Fluorocarbon-22), C/sub 2/Cl/sub 3/F/sub 3/ (Fluorocarbon-113), CH/sub 4/, CO, CO/sub 2/, N/sub 2/O, CH/sub 3/Cl, CCl/sub 4/, CH/sub 3/CCl/sub 3/, OCS and SF/sub 6/ in tropospheric and stratospheric samples. Samples collected during the interception of the plume from the eruption of Mount St. Helens indicate that OCS was injected into the stratosphere during the eruption. A large CO/sub 2/ gradient was found at 19.2 km on this flight.

  2. Amorphous microcellular polytetrafluoroethylene foam film

    NASA Astrophysics Data System (ADS)

    Tang, Chongzheng

    1991-11-01

    We report herein the preparation of novel low-density ultramicrocellular fluorocarbon foams and their application. These fluorocarbon foams are of interest for the biochemistry arena in numerous applications including foodstuff, pharmacy, wine making, beer brewery, fermentation medical laboratory, and other processing factories. All of those require good quality processing programs in which, after eliminating bacterium and virus, compressed air is needed. Ordinarily, compressed air contains bacterium and virus, its size is 0.01 - 2 micrometers fluorocarbon foam films. Having average porous diameter 0.04 - 0.1 micrometers , these are stable to high temperature (280 degree(s)C) and chemical environments, and generally have good engineering and mechanical properties (e.g., low coefficient of thermal expansion, high modulus, and good dimensional stability). Our new process for preparing low density fluorocarbon foams provides materials with unique properties. As such, they offer the possibility for being superior to earlier materials for a number of the filter applications mentioned.

  3. Preparation of stable colloidal dispersions in fluorinated liquids

    NASA Technical Reports Server (NTRS)

    Kaiser, R.

    1972-01-01

    Chemical method for separating oil from water by liquid barrier which can be positioned magnetically is described. Fluorocarbon liquids containing colloidal suspension of magnetite is proposed. Chemical composition of magnetite and fluorinated ether polymer are presented.

  4. 16 CFR 423.1 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... uses any common organic solvent (e.g. petroleum, perchlorethylene, fluorocarbon). The process may also... and agitation. When no temperature is given, e.g., warm or cold, hot water up to 145 degrees F...

  5. 16 CFR 423.1 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... uses any common organic solvent (e.g. petroleum, perchlorethylene, fluorocarbon). The process may also... and agitation. When no temperature is given, e.g., warm or cold, hot water up to 145 degrees F...

  6. 16 CFR 423.1 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... uses any common organic solvent (e.g. petroleum, perchlorethylene, fluorocarbon). The process may also... and agitation. When no temperature is given, e.g., warm or cold, hot water up to 145 degrees F...

  7. Long-lasting solid-polymer electrolytic hygrometer

    NASA Technical Reports Server (NTRS)

    Lawson, D. D.

    1978-01-01

    Device consists of hollow tube node of oxidation-resistant sulfonated fluorocarbon polymer. Tube absorbs moisture from air passing across inner and outer surfaces, causing change in polymer conductance. Change is related to change in water content in gas sample.

  8. Development of an all-metal thick film cost effective metallization system for solar cells

    NASA Technical Reports Server (NTRS)

    Ross, B.; Parker, J.

    1982-01-01

    Electrodes made with pastes produced under the previous contract were analyzed and compared with raw materials. A needle-like structure observed on the electroded solar cell was identified as eutectic copper-silicon, a phase considered to benefit the electrical and metallurgical properties of the contact. Electrodes made from copper fluorocarbon and copper silver fluoride also contained this phase but had poor adhesion. A liquid medium, intended to provide transport during carbon fluoride decomposition was incorporated into the paste resulting in better adhesion. The product survived preliminary environmental tests. A 2 cm by 2 cm solar cell made with fluorocarbon activated copper electrodes and gave 7% AMI efficiency (without AR coating). Both silver fluoride and fluorocarbon screened paste electrodes can be produced for approximately $0.04 per watt.

  9. Novel CO{sub 2}-thickeners for improved mobility control

    SciTech Connect

    Enick, Dr. Robert M.; Beckman, Dr. Eric J.; Hamilton, Dr. Andrew

    2000-02-02

    The objective of this study was to design, synthesize, and characterize thickening agents for dense carbon dioxide and to evaluate their solubility and viscosity-enhancing potential in CO{sub 2}. Hydrocarbon-fluorocarbon random copolymers, sulfated hydrocarbon-fluorocarbon random copolymers, semifluorinated trialkyltin fluorides and small hydrogen-bonding compounds were evaluated. Random copolymers of styrene and heptadecafluorodecyl acrylate were characterized by high solubility ion dense carbon dioxide and the most substantial increases in solution viscosity. Falling cylinder viscometry results indicated that the 29%styrene--71%fluoroacylate bulk-polymerized copolymer induced 2--250 fold increases in viscosity at copolymer concentrations of 0.2--5.0wt%.

  10. Novel CO{sub 2}-thickeners for improved mobility control

    SciTech Connect

    Enick, Dr. Robert M.; Beckman, Dr. Eric J.; Hamilton, Dr. Andrew

    2000-02-02

    The objective of this study was to design, synthesize, and characterize thickening agents for dense carbon dioxide and to evaluate their solubility and viscosity-enhancing potential in CO{sub 2}. Hydrocarbon-fluorocarbon random copolymers, sulfonated hydrocarbon-fluorocarbon random copolymers, semifluorinated trialkyltin fluorides and small hydrogen-bonding compounds have been evaluated. Random copolymers of styrene and heptadecafluorodecyl acrylate yielded substantial increases in viscosity. Falling cylinder viscometry results indicated that the 29%styrene--71%fluoroacrylate bulk-polymerized copolymer induced very significant viscosity increases at copolymer concentrations of 0.1--5.0wt%.

  11. Novel CO{sub 2}-thickeners for improved mobility control

    SciTech Connect

    Enick, Dr. Robert M.; Beckman, Dr. Eric J.; Hamilton, Dr. Andrew

    2000-02-02

    The objective of this study was to design, synthesize, and characterize thickening agents for dense carbon dioxide and to evaluate their solubility and viscosity-enhancing potential in CO{sub 2}. Previously, fluoroacrylate homopolymers and fluorinated telechelic ionomers were shown to increase the viscosity of carbon dioxide by a factor of 3--4 at concentrations of 2--3 at concentrations of 4--5 wt%. This report details the findings for several new types of carbon dioxide thickening candidates. Hydrocarbon-fluorocarbon random copolymers, sulfonated hydrocarbon-fluorocarbon random copolymers, semifluorinated trialkyltin fluorides and small hydrogen-bounding compounds were evaluated.

  12. Development of a special purpose spacecraft interior coating. Phase 2. [fire resistant fluoropolymer coating

    NASA Technical Reports Server (NTRS)

    Bartoszek, E. J.; Christofas, A.; Nannelli, P.

    1977-01-01

    Numerous acrylic and epoxy modifiers for the fluorocarbon latex resin base were investigated. Optimum coatings were developed by modifying the fluorocarbon latex with an epoxy acrylic resin system. In addition, a number of other formulations, containing hard acrylics as modifiers, displayed attractive properties and potential for further improvements. The preferred formulations dried to touch in about one hour and were fully dried in about twenty four hours under normal room temperature and humidity conditions. In addition to physical and mechanical properties either comparable or superior to those of commercial solvent base polyurethane or polyester coatings, the preferred compositions meet the flammability and offgassing requirements specified by NASA.

  13. Synthesis and Solid State Structure of Fluorous Probe Molecules for Fluorous Separation Applications

    PubMed Central

    Lehmler, H.-J.; Telu, S.; Vyas, S.M.; Shaikh, N.S.; Rankin, S.E.; Knutson, B.L.; Parkin, S.

    2010-01-01

    A series of colored hydrocarbon and fluorocarbon tagged 1-fluoro-4-alkylamino-anthraquinones and 1,4-bis-alkylamino-anthraquinone probe molecules were synthesized from a (fluorinated) alkyl amine and 1,4-difluoroanthraquinone to aid in the development of fluorous separation applications. The anthraquinones displayed stacking of the anthraquinone tricycle and interdigitation of the (fluorinated) alkyl chains in the solid state. Furthermore, intramolecular N-HO hydrogen bonds forced the hydrocarbon and fluorocarbon tags into a conformation pointing away from the anthraquinone tricycle, with the angle of the tricycle plane normal and the main (fluorinated) alkyl vector ranging from 1 to 39. Separation of the probe molecules on fluorous silica gel showed that the degree of fluorination of the probe molecules plays only a minor role with most eluents (e.g., hexane-ethyl acetate and methyl nonafluorobutyl ethers-ethyl acetate). However, toluene as eluent caused a pronounced separation by degree of fluorination for fluorocarbon, but not hydrocarbon tagged probe molecules on both silica gel and fluorous silica gel. These studies suggest that hydrocarbon and fluorocarbon tagged anthraquinones are useful probe molecules for the development of laboratory scale fluorous separation applications. PMID:20305832

  14. Fast-drying coating

    NASA Technical Reports Server (NTRS)

    Bartoszek, E. J.

    1978-01-01

    Nontoxic coating has excellent optical properties and can be pigmented in many different colors. It bonds well, can be applied by conventional methods, weathers well, and is self-extinguishing. Coating composition comprises latex blends of fluorocarbons, acrylic resins, stabilizers, modifiers, variety of inorganic pigments, and other additives. Suitable latex primers have also been developed from acrylic latex base.

  15. Gas mixtures for spark gap closing switches

    DOEpatents

    Christophorou, L.G.; McCorkle, D.L.; Hunter, S.R.

    1987-02-20

    Gas mixtures for use in spark gap closing switches comprised of fluorocarbons and low molecular weight, inert buffer gases. To this can be added a third gas having a low ionization potential relative to the buffer gas. The gas mixtures presented possess properties that optimized the efficiency spark gap closing switches. 6 figs.

  16. Lighter-than-Air Science

    ERIC Educational Resources Information Center

    MOSAIC, 1977

    1977-01-01

    Reviews practical applications, particularly in scientific research, of hot air balloons. Recent U.S. governmental projects in near-space research are described. Lists (1) major accomplishments of scientific ballooning, including discoveries in cosmic ray particles, gamma and x-rays, and other radiation; (2) measurement of fluorocarbon

  17. Transparent Thin Films Deposited onto Polyester Film Substrate by Radio Frequency Sputtering with a Poly(tetrafluoroethylene) Target

    NASA Astrophysics Data System (ADS)

    Seino, Shou; Nagai, Yuki; Kobayashi, Masashi; Iwamori, Satoru; Noda, Kazuhiro

    2013-05-01

    Improvement technologies for antireflection property of transparent plastic substrates are required in computer displays. Inorganic coatings have been used to reduce the surface reflection. We have already reported that fluorocarbon thin films sputtered with a poly(tetrafluoroethylene) (PTFE) target are transparent and can be used for an antireflection film, although the pristine PTFE plate used for the sputtering target is white. The fluorocarbon thin films were deposited onto a polyester (PET) film substrate by an rf sputtering, and characterized their optical properties. Elemental ratio, fluorine for carbon, of the thin films increased and degree of cross-linking of the thin films decreased with an increase of the rf power. Arithmetical surface roughness of the fluorocarbon thin films slightly increased with an increase of the rf power. Surface roughness of the fluorocarbon thin film affects the transmittance as well as the chemical structure of the thin film. To enhance the transparency, the diffuse transmittance should be suppressed, and flat surface thin films should be prepared by the sputtering at lower rf power and pressure.

  18. Demonstrating a Lack of Reactivity Using a Teflon-Coated Pan.

    ERIC Educational Resources Information Center

    Richmond, Thomas G.

    1995-01-01

    Illustrates the chemical resistance of polytetrafluoroethene to mineral acids using an ordinary Teflon-coated frying pan. The demonstration can also be used to lead to a discussion of the long lifetimes of fluorocarbons and chlorofluorocarbons in the atmosphere and their roles in the breakdown of the ozone layer. (AIM)

  19. R-123: A balanced selection for low pressure systems

    SciTech Connect

    Smithart, E.L. ); Crawford, J.G. )

    1993-05-01

    This article discusses the selection of a refrigerant for low pressure chiller systems. The topics of the article include selection criteria, adapting to new refrigerants, safety considerations, installation and service, involving the owner, refrigerants as a resource, and retrofit costs. The author endorses the transition from Chlorofluorocarbons (CFCs) to the Halogenated CFCs and Halogenated Fluorocarbons.

  20. Plasma fluorination of diamond-like carbon surfaces: mechanism and application to nanoimprint lithography.

    PubMed

    Schvartzman, M; Wind, S J

    2009-04-01

    Diamond-like carbon (DLC) films, used as molds for nanoimprint lithography, were treated with a fluorocarbon-based plasma in order to enhance their anti-adhesion properties. While ellipsometry and atomic force microscope measurements showed negligible changes in thickness and surface roughness after plasma processing, contact angle measurement found fluorine plasma-treated DLC surfaces to be highly hydrophobic, with surface energy values reduced from approximately 45 mJ m(-2) for untreated films to approximately 20-30 mJ m(-2) after fluorination. X-ray photoelectron spectroscopy revealed a thin (from approximately 0.5 to approximately 3 nm) fluorocarbon layer on the DLC surface. Proposed mechanisms for the formation of this layer include two competing processes: etching of DLC and deposition of fluorocarbon material, with one or the other mechanism dominant, depending on the plasma conditions. Fluorocarbon plasma-treated DLC molds for nanoimprint lithography were used to pattern sub-20 nm size features with a high degree of repeatability, demonstrating an extended lifetime of the anti-adhesion coating. PMID:19420525

  1. Improved Radiography Of Wooden Parts

    NASA Technical Reports Server (NTRS)

    Berry, Maggie L.; Berry, Robert F., Jr.

    1990-01-01

    Technique developed to increase radiographic contrasts of inherent latent defects in wood. Involves introduction of radiopaque substance into defect site and subjecting site to penetrating radiation. Radiopaque penetrant used is commercially available fluorocarbon cleaning solvent, trichlorotrifluoroethane. Applicable in inspection of wooden aircraft components, fan and wind-turbine blades, marine parts, insulators, and other wooden components, assemblies, and structures.

  2. Gas mixtures for spark gap closing switches

    DOEpatents

    Christophorou, Loucas G. (Oak Ridge, TN); McCorkle, Dennis L. (Knoxville, TN); Hunter, Scott R. (Oak Ridge, TN)

    1988-01-01

    Gas mixtures for use in spark gap closing switches comprised of fluorocarbons and low molecular weight, inert buffer gases. To this can be added a third gas having a low ionization potential relative to the buffer gas. The gas mixtures presented possess properties that optimized the efficiency spark gap closing switches.

  3. 46 CFR 130.230 - Protection from refrigerants.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Protection from refrigerants. 130.230 Section 130.230... refrigerants. (a) For each refrigeration system that exceeds 0.6 cubic meters (20 cubic feet) of storage... storage capacity if using a fluorocarbon, as a refrigerant, there must be available one...

  4. 46 CFR 130.230 - Protection from refrigerants.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Protection from refrigerants. 130.230 Section 130.230... refrigerants. (a) For each refrigeration system that exceeds 0.6 cubic meters (20 cubic feet) of storage... storage capacity if using a fluorocarbon, as a refrigerant, there must be available one...

  5. 46 CFR 130.230 - Protection from refrigerants.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Protection from refrigerants. 130.230 Section 130.230... refrigerants. (a) For each refrigeration system that exceeds 0.6 cubic meters (20 cubic feet) of storage... storage capacity if using a fluorocarbon, as a refrigerant, there must be available one...

  6. 46 CFR 130.230 - Protection from refrigerants.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Protection from refrigerants. 130.230 Section 130.230... refrigerants. (a) For each refrigeration system that exceeds 0.6 cubic meters (20 cubic feet) of storage... storage capacity if using a fluorocarbon, as a refrigerant, there must be available one...

  7. 46 CFR 130.230 - Protection from refrigerants.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Protection from refrigerants. 130.230 Section 130.230... refrigerants. (a) For each refrigeration system that exceeds 0.6 cubic meters (20 cubic feet) of storage... storage capacity if using a fluorocarbon, as a refrigerant, there must be available one...

  8. GLOBAL DISTRIBUTION OF SELECTED HALOCARBONS, HYDROCARBONS, SF6, AND N2O

    EPA Science Inventory

    Northern and Southern hemispheric distributions of halogenated species, hydrocarbons, SF6, and N2O are presented. The atmospheric growth rates of selected halocarbons and N2O are characterized. The fluorocarbon 11 and 12 global burden and hemispheric distribution is consistent wi...

  9. Combustion of PTFE: The effects of gravity on ultrafine particle generation

    NASA Technical Reports Server (NTRS)

    McKinnon, Thomas; Todd, Paul; Oberdorster, Gunter

    1996-01-01

    The objective of this project is to obtain an understanding of the effect of gravity on the toxicity of ultrafine particle and gas phase materials produced when fluorocarbon polymers are thermally degraded or burned. The motivation for the project is to provide a basic technical foundation on which policies for spacecraft health and safety with regard to fire and polymers can be formulated.

  10. Biology and Politics

    ERIC Educational Resources Information Center

    Whiting, Pat

    1977-01-01

    A state representative from Oregon uses his state as example for political action regarding critical sociobiological issues having great bearing on world ecosystems: pollution, energy-resource allocation, and population density. Discusses ozone depletion, use of fluorocarbons, and the Oregon Energy Policy. Suggests methods of involving educators.…

  11. Formation of C2 Radicals in High-Density C4F8 Plasmas Studied by Laser-Induced Fluorescence

    NASA Astrophysics Data System (ADS)

    Suzuki, Chihiro; Sasaki, Koichi; Kadota, Kiyoshi

    1999-12-01

    Spatial and temporal variations of C2 radical density in high-density C4F8 plasmas have been investigated by laser-induced fluorescence (LIF) spectroscopy. Hollow-shaped spatial distributions have been observed for the C2 density, indicating that C2 radicals are produced from fluorocarbon film on the chamber wall and are lost in the plasma column by electron impact processes. The C2 density depends largely on the seasoning condition of the vacuum chamber, which supports the surface production of C2 radicals. Bombardment of positive ions onto fluorocarbon film is necessary for such surface production. The mechanism of this surface production is not the physical sputtering of fluorocarbon film but ion-enhanced chemical reactions with fluorocarbon film. Lifetime measurements of C2 radicals have also been carried out in the afterglow. The observed decay time constants (less than 0.8 ms) are shorter for high gas pressures, indicating the loss of C2 due to gas-phase reactions.

  12. Use of an organoleptic tracer (mercaptan) for testing for leaks in safety equipment.

    PubMed

    Malligo, J E

    1977-12-01

    A safe, rapid, sensitive, and economical method is presented for detecting leaks in gas-tight laboratory cabinets and other apparatus. This method, using no fluorocarbons and requiring no prior decontamination, is effective under negative, neutral, or positive chamber conditions. PMID:596879

  13. Comparative description of PFAA developmental toxicity: An update

    EPA Science Inventory

    The perfluoroalkyl acids (PFAAs) are a family of fluorocarbons consisting of a perfluorinated carbon tail (typically 4-12 carbons in length) and an acidic functional moiety, usually carboxylate or sulfonate. These compounds have excellent surface tension reducing properties and h...

  14. High-power, ultralow-mass solar arrays: FY-77 solar arrays technology readiness assessment report, volume 2

    NASA Technical Reports Server (NTRS)

    Costogue, E. N.; Young, L. E.; Brandhorst, H. W., Jr.

    1978-01-01

    Development efforts are reported in detail for: (1) a lightweight solar array system for solar electric propulsion; (2) a high efficiency thin silicon solar cell; (3) conceptual design of 200 W/kg solar arrays; (4) fluorocarbon encapsulation for silicon solar cell array; and (5) technology assessment of concentrator solar arrays.

  15. improving maser frequency stability

    NASA Technical Reports Server (NTRS)

    Crampton, S. B.

    1980-01-01

    Hydrogen maser frequency standard is more stable by addition of parallel pyrex capillary tube array collimator. With collimator, maser line width has been made as narrow as 0.24 hertz representing fivefold improvement over maser without collimator. Fluorocarbon coating in tubes virtually eliminates energy loss in collimator.

  16. Biology and Politics

    ERIC Educational Resources Information Center

    Whiting, Pat

    1977-01-01

    A state representative from Oregon uses his state as example for political action regarding critical sociobiological issues having great bearing on world ecosystems: pollution, energy-resource allocation, and population density. Discusses ozone depletion, use of fluorocarbons, and the Oregon Energy Policy. Suggests methods of involving educators.

  17. The Great Spray Can Debate.

    ERIC Educational Resources Information Center

    Bassow, Herb

    This booklet, designed to be used in high school classrooms, concerns the technological, economic, and political contexts of the fluorocarbon-ozone depletion controversy. The curriculum is divided into three phases: the scientific dimension, which is a pure science analysis using lab-classroom tools and methodologies; the philosophical dimension,

  18. RETENTION OF HALOCARBONS ON A HEXAFLUOROPROPYLENE EPOXIDE-MODIFIED GRAPHITIZED CARBON BLACK - IV. PROPANE- BASED COMPOUNDS

    EPA Science Inventory

    The retention characteristics of 25 propane-based bromofluorocarbon, chlorocarbon, chlorofluorocarbon, and fluorocarbon fluids have been studied as a function of temperature on a stationary phase consisting of a 5% (m/m) coating of a low-molecular-mass polymer of hexafluoropropyl...

  19. Cardiovascular disease and environmental exposure.

    PubMed Central

    Rosenman, K D

    1979-01-01

    This paper reviews the possible association between cardiovascular disease and occupational and environmental agents. The effects of carbon monoxide, fibrogenic dusts, carbon disulphide, heavy metals, noise, radiation, heat, cold, solvents and fluorocarbons are discussed. New directions for investigation are suggested. PMID:465378

  20. Organofluorine chemistry: A Janus cyclohexane ring

    NASA Astrophysics Data System (ADS)

    Santschi, Nico; Gilmour, Ryan

    2015-06-01

    The first synthesis of the all-cis isomer of 1,2,3,4,5,6-hexafluorocyclohexane, a molecule with one hydrocarbon face and one fluorocarbon face, is a tour de force of organofluorine chemistry and opens up new possibilities for molecular design.

  1. Accurate Lipophilicity (log?P) Measurements Inform on Subtle Stereoelectronic Effects in Fluorine Chemistry.

    PubMed

    O'Hagan, David; Young, Robert J

    2016-03-14

    Polar exploration: Recently, Linclau and co-workers disclosed a straightforward (19) F-NMR method for determining the log?P values of fluorocarbons. The method is particularly useful for most polar compounds and provides a quantitative way to rationalize the more subtle stereoelectronic consequences of fluorine introduction. PMID:26894548

  2. Development of an all-metal thick-film cost-effective metallization system for solar cells

    NASA Technical Reports Server (NTRS)

    Ross, B.

    1981-01-01

    Screened electrodes made from fluorocarbon activated copper paste and silver fluoride activated copper paste, tape adhesion and scratch tests were studied. Experiments were conducted with variations in past parameters, firing conditions, including gas ambients, furnace furniture, silicon surface and others. A liquid medium intended to provide transport during the carbon fluoride decomposition, is incorporated in the paste.

  3. Surface properties and aggregate morphology of partially fluorinated carboxylate-type anionic gemini surfactants.

    PubMed

    Yoshimura, Tomokazu; Bong, Miri; Matsuoka, Keisuke; Honda, Chikako; Endo, Kazutoyo

    2009-11-01

    Three anionic homologues of a novel partially fluorinated carboxylate-type anionic gemini surfactant, N,N'-di(3-perfluoroalkyl-2-hydroxypropyl)-N,N'-diacetic acid ethylenediamine (2C(n)(F) edda, where n represents the number of carbon atoms in the fluorocarbon chain (4, 6, and 8)) were synthesized. In these present gemini surfactants, the relatively small carboxylic acid moieties form hydrophilic head groups. The surface properties or structures of the aggregates of these surfactants are strongly influenced by the nonflexible fluorocarbons and small head groups; this is because these surfactants have a closely packed molecular structure. The equilibrium surface tension properties of these surfactants were measured at 298.2K for various fluorocarbon chain lengths. The plot of the logarithm of the critical micelle concentration (cmc) against the fluorocarbon chain lengths for 2C(n)(F) edda (n=4, 6, and 8) showed a minimum for n=6. Furthermore, the lowest surface tension of 2C(6)(F) edda at the cmc was 16.4mNm(-1). Such unique behavior has not been observed even in the other fluorinated surfactants. Changes in the shapes and sizes of these surfactant aggregate with concentration were investigated by dynamic light scattering and transmission electron microscopy (TEM). The TEM micrographs showed that in an aqueous alkali solution, 2C(n)(F) edda mainly formed aggregates with stringlike (n=4), cagelike (n=6), and distorted bilayer structures (n=8). The morphological changes in the aggregates were affected by the molecular structure composed of nonflexible fluorocarbon chains and flexible hydrocarbon chains. PMID:19683716

  4. Influence of counterions on micellization of tetramethylammonium perfluorononanoic carboxylate in 1-butyl-3-methylimidazolium ionic liquid.

    PubMed

    Long, Panfeng; Chen, Jingfei; Wang, Dong; Hu, Ziqi; Gao, Xuedong; Li, Ziran; Hao, Jingcheng

    2012-07-01

    The influence of counterions on micellization of perfluorononanoic carboxylate ammonium salts in water and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF(4)) solutions was investigated by surface tension and (19)F NMR measurements and freeze-fracture transmission electron microscopy (FF-TEM) observations. Changes in the counterions of the fluorocarbon surfactants have different effects on the two solvents. With the increase of counterion volume, the critical micelle concentration (cmc) value of relevant fluorinated surfactant decreases in aqueous solutions. This is because the counterions with larger size, such as (+)N(CH(3))(4), can be little hydrated, which can screen the electrostatic repulsion of the headgroups of the fluorocarbon surfactant and thus facilitate micelle formation. However, the fluorocarbon surfactants can dissolve and form micelles in [bmim]BF(4) only when they provide with largest counterion such as (+)N(CH(3))(4). This is because the counterion, (+)N(CH(3))(4), disperses the charge of the cations, which could weaken the electrostatic interaction between the ion pair of the surfactant, leading to a higher degree of counterion binding. The thermodynamic parameters estimated from the temperature dependence of the cmc values tell us that the micelle formation for tetramethylammonium perfluorononanoic carboxylate (C(8)F(17)COON(CH(3))(4), PFNT) in ionic liquids (ILs) is an entropy-driven process at low temperature but an enthalpy-driven process at high temperature. The driving force of the micellization for fluorocarbon surfactants in [bmim]BF(4) is the solvophobic effect, due to the hydrophobic and oleophobic properties of fluorocarbon chains. PMID:22690854

  5. Seal Materials Compatible with the Electroplating Solvent Used in Constellation-X Mirrors

    NASA Technical Reports Server (NTRS)

    Pei, Xiong-Skiba

    1999-01-01

    The existing gasket seals used in electroplating of the Constellation-X mirrors are difficult to assemble, and the current seal material is hydrophobic and too thick. The combination of the above problems result in: 1) non-uniform plating; 2) defect sites such as pits on the mirror edges; 3) "bear claws" on the edges of the mandrels and mirrors causing difficulties in shell-mirror separations; and 4) leakage of the plating solution past the seals into the mandrel causing chemical etching of the mandrel interior. This paper reports the results of this summer study in searching for alternate seal materials chemically compatible with the electroplating solvent. Fifteen common elastomeric rubber seal materials made-by Parker Seals were investigated including butyl, ethylene propylene, fluorosilicone, nitrile, Viton fluorocarbon, and silicone. Test results showed that Viton fluorocarbon compounds as a group were superior to the other tested compounds for chemical compatibility with the plating bath.

  6. Reactivation of Newcastle Disease Virus Neutralized by Antibody.

    PubMed Central

    Brugh, M

    1977-01-01

    In an effort to improve current technology for detection of Newcastle disease virus in convalescent birds, a procedure has been developed for efficient reactivation of virus that has been neutralized by antibody. The reactivation capabilities of fluorocarbon treatment, ultrasonic treatment, pH extremes, and proteolytic digestion were evaluated using the LaSota strain of virus. Reactivation was maximum after proteolytic digestion with either trypsin or papain, and reactivation effciency was up to 100%, depending on the enzyme used for digestion and the amount of antibody in the neutralization mixture. Reactivation at pH extremes was considerably less efficient than reactiviation by proteolytic digestion, and neither fluorocarbon nor ultrasonic treatments effectively recovered antibody-neutralized Newcastle disease virus. PMID:16035

  7. Novel Sorption/Desorption Process for Carbon Dioxide Capture (Feasibility Study)

    SciTech Connect

    William Tuminello; Maciej Radosz; Youqing Shen

    2008-11-01

    Western Research Institute and the University of Wyoming Enhanced Oil Recovery Institute have tested a novel approach to carbon dioxide capture in power plants and industrial operations. This approach is expected to provide considerable cost savings, in terms of regeneration of the sorbent. It is proposed that low molecular weight, low volatility liquid fluorocarbons be utilized to absorb CO{sub 2} due to their unusual affinity for the gas. The energy savings would be realized by cooling the fluorocarbon liquids below their melting point where the CO{sub 2} would be released even at elevated pressure. Thus, the expense of heating currently used sorbents, saturated with CO{sub 2}, under low pressure conditions and then having to compress the released gas would not be realized. However, these fluorinated materials have been shown to be poor carbon dioxide absorbers under conditions currently required for carbon capture. The project was terminated.

  8. Nanometer-scale water- and proton-diffusion heterogeneities across water channels in polymer electrolyte membranes.

    PubMed

    Song, Jinsuk; Han, Oc Hee; Han, Songi

    2015-03-16

    Nafion, the most widely used polymer for electrolyte membranes (PEMs) in fuel cells, consists of a fluorocarbon backbone and acidic groups that, upon hydration, swell to form percolated channels through which water and ions diffuse. Although the effects of the channel structures and the acidic groups on water/ion transport have been studied before, the surface chemistry or the spatially heterogeneous diffusivity across water channels has never been shown to directly influence water/ion transport. By the use of molecular spin probes that are selectively partitioned into heterogeneous regions of the PEM and Overhauser dynamic nuclear polarization relaxometry, this study reveals that both water and proton diffusivity are significantly faster near the fluorocarbon and the acidic groups lining the water channels than within the water channels. The concept that surface chemistry at the (sub)nanometer scale dictates water and proton diffusivity invokes a new design principle for PEMs. PMID:25630609

  9. Use of an excimer lamp for photochemical resistless etching of thermal silicon oxide substrate

    SciTech Connect

    Kamata, N.; Murahara, M.

    1996-12-31

    Photochemical resistless etching was carried out by using a Xe{sub 2}* excimer lamp and a KrF excimer laser. The decomposition method with Xe{sub 2}* excimer lamp increases the decomposition efficiency by 100 times than that of using ArF excimer laser and etchant gas, CHClF{sub 2}. Xe{sub 2}* excimer lamp irradiation allowed decomposition of CHClF{sub 2} gas to produce CF{sub 2} radical with a small quantity of gas. The CF{sub 2} radical was polymerized to form fluorocarbon layer on the SiO{sub 2} substrate. Simultaneously, circuit patterned KrF excimer laser was vertically irradiated the fluorocarbon layer on the substrate for resistless etching. The etching depth was about 1,000 {angstrom}.

  10. Evaluation of Vacuum Ultraviolet Irradiation Influence under Xenon Excimer Lamp Processing Employing a Quartz Crystal Microbalance with Organic Thin Film

    NASA Astrophysics Data System (ADS)

    Yoshino, Kiyoshi; Matsumoto, Hiroyuki; Iwasaki, Tatsuyuki; Kinoshita, Shinobu; Noda, Kazutoshi; Iwamori, Satoru

    2013-05-01

    The xenon excimer lamp, which emits vacuum ultraviolet radiation, is frequently used as a dry cleaning device for objects such as flat-panel displays (FPDs). UV dry cleaning processes are generally monitored with UV illuminometers, however these do not detect the direct influence of the cleaning process on the substrate. Therefore, a monitoring method that focuses on the treated substrate is required. In this study, we investigated a method to evaluate VUV influence under xenon excimer lamp processing, using a quartz crystal microbalance technique which can detect very small changes in mass. With an organic (fluorocarbon) thin film as the detecting element of the quartz crystal microbalance, we have investigated mass change through irradiation with a xenon excimer lamp, in nitrogen, oxygen, and air atmosphere, respectively. It was confirmed that mass change increased linearly with time, under all conditions, and that monitoring of VUV influence was possible by means of the quartz crystal microbalance method using fluorocarbon thin film.

  11. Hydrocarbon foams

    SciTech Connect

    Raynolds, S.; Fournier, L.B.

    1984-02-21

    Liquid hydrocarbon foams containing from 0.05 to 5 wt. % of a fluorocarbon polymer containing from 25 to 60 wt. % units of the structure (C(-R/sub 2/)(-COO-(CH/sub 2/)N-(CF/sub 2/-CF/sub 2/)-R1)-CH/sub 2/) where -R/sup 1/ is -H or -F, m is an integer from 2 to 10, and n is 1 or 2 and 75 to 40 wt. % units of the structure (CH(-R/sub 2/)(-COO-R/sub 3/)-CH/sub 2/) where -R/sub 3/ is an alkyl group containing from 10 to 20 carbon atoms. The foams are useful as oil and gas well fracturing fluids and for applying the fluorocarbon polymer to textiles as an oil and water repellant.

  12. A facile method of fabricating mechanical durable anti-icing coatings based on CeO2 microparticles

    NASA Astrophysics Data System (ADS)

    Wang, Pengren; Peng, Chaoyi; Wu, Binrui; Yuan, Zhiqing; Yang, Fubiao; Zeng, Jingcheng

    2015-07-01

    Compromising between hydrophobicity and mechanical durability may be a feasible approach to fabricating usable anti-icing coatings. This work improves the contact angle of current commercial anti-icing coatings applied to wind turbine blades dramatically and keeps relatively high mechanical durability. CeO2 microparticles and diluent were mixed with fluorocarbon resin to fabricate high hydrophobic coatings on the glass fiber reinforced epoxy composite substrates. The proportion of CeO2 microparticles and diluent influences the contact angles significantly. The optimum mass ratio of fluorocarbon resin to CeO2 microparticles to diluent is 1:1.5:1, which leads to the highest contact angle close to 140. The microscopy analysis shows that the CeO2 microparticles form nano/microscale hierarchical structure on the surface of the coatings.

  13. Investigation of test methods, material properties and processes for solar cell encapsulants

    NASA Technical Reports Server (NTRS)

    Willis, P. B.; Baum, B.

    1977-01-01

    The potentially useful encapsulating materials for Task 3 of the Low-Cost Silicon Solar Array project were studied to identify, evaluate, and recommend encapsulant materials and processes for the production of cost-effective, long-life solar cell modules. Materials for study were chosen on the basis of existing knowledge of generic chemical types having high resistance to environmental weathering. The materials varied from rubbers to thermoplastics and presented a broad range of mechanical properties and processing requirements. Basic physical and optical properties were measured on the polymers and were redetermined after exposure to indoor artificial accelerated aging conditions covering four time periods. Strengths and weaknesses of the various materials were revealed and data was accumulated for the development of predictive methodologies. To date, silicone rubbers, fluorocarbons, and acrylic polymers appear to have the most promising combination of characteristics. The fluorocarbons may be used only as films, however, because of their high cost.

  14. Aqueous Solution Properties of Pyridinium-Type Perfluorinated Surfactants and Simulation of Mixture CMC.

    PubMed

    Asakawa, Tsuyoshi; Ishikawa, Kenji; Miyagishi, Shigeyoshi

    2001-08-01

    The critical micelle concentrations (CMCs) of 1,1,2,2-tetrahydroperfluoroalkylpyridinium chloride have been determined by measurements of surface tension and electrical conductivity, etc. The CMCs of perfluorinated surfactants were only about 0.02 times that of hydrocarbon one with the same carbon number. Aqueous solutions of fluorocarbon surfactants gave low surface tensions in comparison with those of hydrocarbon surfactants. The area per surfactant molecule at the air-water interface decreased with increasing length of the fluorocarbon chain. Electromotive force measurements were made with chloride-responsive electrodes on surfactants solutions. The micelle ionization degrees decreased with increasing length of the alkyl chain. The group contribution method simulated the mixture CMCs of binary surfactants with various alkyl chain lengths. The group contribution method proved to be very useful to predict not only the mixture CMCs but also the demixing regions of binary mixtures having great differences in CMC. Copyright 2001 Academic Press. PMID:11446820

  15. Thermal stability of electron-irradiated poly(tetrafluoroethylene) - X-ray photoelectron and mass spectroscopic study

    NASA Technical Reports Server (NTRS)

    Wheeler, Donald R.; Pepper, Stephen V.

    1990-01-01

    Polytetrafluoroethylene (PTFE) was subjected to 3 keV electron bombardment and then heated in vacuum to 300 C. The behavior of the material as a function of radiation dose and temperature was studied by X-ray photoelectron spectroscopy (XPS) of the surface and mass spectroscopy of the species evolved. Lightly damaged material heated to 300 C evolved saturated fluorocarbon species, whereas unsaturated fluorocarbon species were evolved from heavily damaged material. After heating the heavily damaged material, those features in the XPS spectrum that were associated with damage diminished, giving the appearance that the radiation damage had annealed. The observations were interpreted by incorporating mass transport of severed chain fragments and thermal decomposition of severely damaged material into the branched and cross-linked network model of irradiated PTFE. The apparent annealing of the radiation damage was due to covering of the network by saturated fragments that easily diffused through the decomposed material to the surface region upon heating.

  16. X-ray photoelectron and mass spectroscopic study of electron irradiation and thermal stability of polytetrafluoroethylene

    NASA Technical Reports Server (NTRS)

    Wheeler, Donald R.; Pepper, Stephen V.

    1990-01-01

    Polytetrafluoroethylene (PTFE) was subjected to 3 keV electron bombardment and then heated in vacuum to 300 C. The behavior of the material as a function of radiation dose and temperature was studied by X-ray photoelectron spectroscopy (XPS) of the surface and mass spectroscopy of the species evolved. A quantitative comparison of the radiation dose rate with that in other reported studies showed that, for a given total dose, the damage observed by XPS is greater for higher dose rates. Lightly damaged material heated to 300 C evolved saturated fluorocarbon species, whereas unsaturated fluorocarbon species evolved from heavily damaged material. After heating the heavily damaged material, those features in the XPS that were associated with damage diminished, giving the appearance that the radiation damage annealed. The apparent annealing of the radiation damage was found to be due to the covering of the network by saturated fragments that easily diffused through the decomposed material to the surface region upon heating.

  17. Preparation and Analysis of Type II Xerogel Films with Antifouling/Foul Release Characteristics

    NASA Astrophysics Data System (ADS)

    Sokolova, Anastasiya

    In order to combat biofouling, xerogel coatings comprised of aminopropyl, fluorocarbon, and hydrocarbon silanes were prepared and tested for their antifouling/foul release properties against Ulva, Navicula, barnacles, and tubeworms. Many of the coatings showed settlement and removal of Ulva to be as good as or better than the poly(dimethylsiloxane) (PDMSE) standard. Barnacle removal assays showed excellent results for some coatings while others did not fair so well. The best foul release coatings for barnacles were comprised of aminopropyl/hydrocarbon- and fluorocarbon/hydrocarbon-modified silanes. For the majority of coatings tested, water wettability and surface energy did not play a role in the antifouling/ foul release properties of the coatings.

  18. Novel CO{sub 2}-thickeners for improved mobility control

    SciTech Connect

    Enick, Dr. Robert M.; Beckman, Dr. Eric J.; Hamilton, Dr. Andrew

    2000-02-02

    The objective of this study was to design, synthesize, and characterize thickening agents for dense carbon dioxide and to evaluate their solubility and viscosity-enhancing potential in CO{sub 2}. Previously, hydrocarbon-fluorocarbon random copolymers, sulfated hydrocarbon-fluorocarbon random copolymers, semifluorinated trialkyltin fluorides and small hydrogen-bonding compounds were evaluated. Random copolymers of styrene and heptadecafluorodecyl acrylate yielded substantial increases in viscosity. The amount of styrene varied between 22--40 mole% in the copolymer. Falling cylinder viscometry results indicated that the 29% styrene--71% fluoroacrylate copolymer induced (at 295K and 34.5 Mpa) increases of 10, 60 and 250 at copolymer concentrations of 1, 3 and 5wt%, respectively.

  19. Scientific Assessment of Stratospheric Ozone: 1989, volume 2. Appendix: AFEAS Report

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The results are presented of the Alternative Fluorocarbon Environmental Acceptability Study (AFEAS), which was organized to evaluate the potential effects on the environment of alternate compounds targeted to replace fully halogenated chlorofluorocarbons (CFCs). All relevant current scientific information to determine the environmental acceptability of the alternative fluorocarbons. Special emphasis was placed on: the potential of the compounds to affect stratospheric ozone; their potential to affect tropospheric ozone; their potential to contribute to model calculated global warming; the atmospheric degradation mechanisms of the compounds, in order to identify their products; and the potential environmental effects of the decomposition products. The alternative compounds to be studied were hydrofluorocarbons (HFCs) with one or two carbon atoms and one or more each of fluorine and hydrogen.

  20. New textile composite materials development, production, application

    NASA Technical Reports Server (NTRS)

    Mikhailov, Petr Y.

    1993-01-01

    New textile composite materials development, production, and application are discussed. Topics covered include: super-high-strength, super-high-modulus fibers, filaments, and materials manufactured on their basis; heat-resistant and nonflammable fibers, filaments, and textile fabrics; fibers and textile fabrics based on fluorocarbon poylmers; antifriction textile fabrics based on polyfen filaments; development of new types of textile combines and composite materials; and carbon filament-based fabrics.

  1. International research into chlorofluorocarbon (CFC) alternatives

    SciTech Connect

    Marseille, T.J.; Shankle, D.L.; Thurman, A.G.

    1992-05-01

    Selected researchers from 21 countries were queried through questionnaires about their current and planned research activities. The results of the survey show that the majority of research being conducted by the respondents is devoted to investigating the hydrogenated fluorocarbon HFC-134a as a replacement for CFC-12 in refrigeration applications. The main issue with this alternative is identifying compatible lubricants that do not reduce its effectiveness.

  2. Development of a special purpose spacecraft interior coating, phase 3

    NASA Technical Reports Server (NTRS)

    Gillman, H. D.; Nannelli, P.

    1979-01-01

    A variety of intumescent coatings based on a fluorocarbon latex resin modified with either an acrylic resin or an epoxy resin were prepared. Several intumescent systems were used for these studies including some based on ammonium polyphosphate and others based on sulfanilamide. The best coatings developed had a high concentration (60-70% by wt.) of intumescent additives and had to be applied thick, approximately 100 mils, in order to have adequate intumescent/fire protection properties.

  3. Development of an all-metal thick film cost effective metallization system for solar cells

    NASA Technical Reports Server (NTRS)

    Ross, B.; Parker, J.

    1983-01-01

    Improved thick film solar cell contacts for the high volume production of low cost silicon solar arrays are needed. All metal screenable pastes made from economical base metals and suitable for application to low to high conductivity silicon were examined. Silver fluoride containing copper pastes and fluorocarbon containing copper pastes were discussed. The effect of hydrogen on the adhesion of metals to silicon was investigated. A cost analysis of various paste materials is provided.

  4. Decompression incidence in air- and liquid-breathing hamsters.

    PubMed

    Lynch, P R; Wilson, J S; Shaffer, T H; Cohen, N

    1983-03-01

    The effects of hyperbaric compression on heart rate, rectal temperature, respiratory rate, bubble formation, and survival were studied in three groups of anesthetized golden hamsters (Mesocricetus auratus). Group I (15 animals) breathed air while exposed to 7 ATA of pressure for 1 h in a hyperbaric chamber; Group II (13 animals), at the same pressure level (7 ATA) and for the same time period (1 h), breathed an oxygenated fluorocarbon liquid (temperature 27 degrees C) that was open to the chamber atmosphere; Group III (10 animals), at the same pressure and time period as the other groups, were sealed in a flexible plastic bag filled with oxygenated fluorocarbon as a breathing mixture. A fourth, Group IV (12 animals), breathed oxygenated fluorocarbon for 1 h at 1 ATA. Survival after rapid decompression in each group varied, 9 animals died in Group I, 12 animals in Group II, whereas none of the animals died in either Groups III or IV. Thirty minutes after decompression postmortem examinations of all the animals demonstrated the presence of large amounts of gas bubbles in the right ventricle and some gas bubbles in the left ventricle of all the hamsters in Groups I and II. No gas bubbles were found in the hearts of the Group III animals. Group III animals, breathing a liquid unsaturated by an inert gas, survived rapid explosive decompression without the signs and symptoms of decompression sickness. Immersion in the liquid fluorocarbon produced a profound decrease in heart rate, rectal temperature, and respiration in Groups II, III, and IV. PMID:6868175

  5. 40 CFR Appendix Viii to Part 261 - Hazardous Constituents

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... P013 Bendiocarb 1,3-Benzodioxol-4-ol, 2,2-dimethyl-, methyl carbamate 22781-23-3 U278 Bendiocarb phenol...-, methylcarbamate 1563-66-2 P127 Carbofuran phenol 7-Benzofuranol, 2,3-dihydro-2,2-dimethyl- 1563-38-8 U367 Carbon... ethane, N.O.S. 1 Chlorinated fluorocarbons, N.O.S. 1 Chlorinated naphthalene, N.O.S. 1 Chlorinated...

  6. 40 CFR Appendix Viii to Part 261 - Hazardous Constituents

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... P013 Bendiocarb 1,3-Benzodioxol-4-ol, 2,2-dimethyl-, methyl carbamate 22781-23-3 U278 Bendiocarb phenol...-, methylcarbamate 1563-66-2 P127 Carbofuran phenol 7-Benzofuranol, 2,3-dihydro-2,2-dimethyl- 1563-38-8 U367 Carbon... ethane, N.O.S. 1 Chlorinated fluorocarbons, N.O.S. 1 Chlorinated naphthalene, N.O.S. 1 Chlorinated...

  7. 40 CFR Appendix Viii to Part 261 - Hazardous Constituents

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... P013 Bendiocarb 1,3-Benzodioxol-4-ol, 2,2-dimethyl-, methyl carbamate 22781-23-3 U278 Bendiocarb phenol...-, methylcarbamate 1563-66-2 P127 Carbofuran phenol 7-Benzofuranol, 2,3-dihydro-2,2-dimethyl- 1563-38-8 U367 Carbon... ethane, N.O.S. 1 Chlorinated fluorocarbons, N.O.S. 1 Chlorinated naphthalene, N.O.S. 1 Chlorinated...

  8. Greenhouse effect of chlorofluorocarbons and other trace gases

    NASA Technical Reports Server (NTRS)

    Hansen, James; Lacis, Andrew; Prather, Michael

    1989-01-01

    A comparison is made of the radiative (greenhouse) forcing of the climate system due to changes of atmospheric chlorofluorocarbons and other trace gases. It is found that CFCs, defined to include chlorofluorocarbons, chlorocarbons, and fluorocarbons, now provide about one-quater of current annual increases in anthropogenic greenhouse climate forcing. If the growth rates of CFC production in the early 1970s had continued to the present, current annual growth of climate forcing due to CFCs would exceed that due to CO2.

  9. General Chemistry Division. Quarterly report, October-December 1979

    SciTech Connect

    Not Available

    1980-02-15

    Progress is reported on analytical R and D for the nuclear explosives programs (coupling of gas chromatograph, mass spectrometer, and infrared spectrometer; analysis of fluorocarbon FC-86; far-infrared laser development; transient behavior of n-type TiO/sub 2/ semiconductor photoelectrodes; and impurities on Kevlar 49 fibers) and for the energy programs (on-line mass spectroscopy of oil shale and testing of additives for controlling the scaling of hypersaline geothermal brine). (DLC)

  10. The synthesis of poly(ether ether ketone) (PEEK) derived from 1,1-bis(4-hydroxyphenyl)-1-phenyl-2,2,3,3,4,4,4-heptafluorobutane

    SciTech Connect

    Peterman, J.A.; Feld, W.A.

    1995-12-31

    Poly(ether ether ketone)s (PEEK) are of interest due to their high thermal stability. Most PEEK materials are prepared by aromatic nucleophilic substitution between an activated aromatic dihalide and an alkali-metal bisphenolate in polar, aprotic solvents. We now report the preparation of a PEEK containing an extended fluorocarbon chain in the bisphenol, analogous to that produced by McGrath, et. al which contained a trifluoromethyl group in the bisphenol, and examine the effect on thermal properties.

  11. Fuel cell ion-exchange membrane investigation

    NASA Technical Reports Server (NTRS)

    Toy, M. S.

    1972-01-01

    The present deficiencies in the fluorocarbon sulfonic acid membrane used as the solid polymer electrolyte in the H2/O2 fuel cell are studied. Considered are: Adhesives selection, elastomeric formulations, scavenger exploration, and membrane characterization. The significant data are interpreted and recommendations are given for both short and long range further investigations in two of the four major areas: membrane adhesives and membrane stabilization.

  12. Fluorination of silicone rubber by plasma polymerization

    NASA Astrophysics Data System (ADS)

    Fielding, Jennifer Chase

    Plasma polymerized fluorocarbon (PPFC) films were deposited onto various silicone rubber substrates, including O-rings, to decrease oil uptake. Depositions were performed using a radio frequency (rf)-powered plasma reactor and various fluorocarbon monomers, such as C2F6, C2F 5H, C3F6, and 1H,1H,2H-perfluoro-1-dodecene. PPFC films which were most promising for inhibiting oil uptake were deposited with 1H,1H,2H-perfluoro-1-dodecene, and were composed predominantly of perfluoromethylene (CF2) species. These films displayed low critical surface energies (as low as 2.7 mJ/m2), and high contact angles with oil (84), which were correlated with the amount of CF2 species present in the film. For the films with the highest degree of CF2 (up to 67%), CF2 chains may have been oriented slightly perpendicular to the substrate and terminated by CF3 species. Adhesion of the PPFC films directly to silicone rubber was found to be poor. However, when a plasma polymerized hydrocarbon interlayer was deposited on the silicone rubber prior to the fluorocarbon films, adhesion was excellent. O-rings coated with multilayer fluorocarbon films showed 2.6% oil uptake after soaking in oil for 100 hrs at 100C. Due to variability in data, and the low quality of the industrial grade silicone rubber, the oil uptake mechanism was determined to be from oil flowing through flaws in the film due to defects within the substrate, not from generalized diffusion through the film. This mechanism was confirmed using higher quality silicone rubber, which showed little or no oil diffusion. Therefore, this film may perform well as an oil-repelling barrier when deposited on a high quality silicone rubber.

  13. Novel fluorohydrocarbons

    NASA Technical Reports Server (NTRS)

    Scherer, Kirby V. (Inventor)

    1979-01-01

    Novel fluorohydrocarbons include a fluoroalkyl unit terminating in a tertiary carbon atom which is directly linked to an aliphatic moiety of the compound. The compounds contain at least 9 carbon atoms and usually no more than 13 carbon atoms. The compounds are synthesized by addition of a fluoride atom to the tertiary carbon atom of a fluorocarbon material to form a carbanion followed by alkylation of the carbanion. The fluorohydrocarbons will find use as blood substitutes or as electronic fluids.

  14. Effect of electron beam irradiation on the properties of crosslinked rubbers

    NASA Astrophysics Data System (ADS)

    Banik, Indranil; Bhowmick, Anil K.

    2000-05-01

    Influence of electron beam (EB) irradiation on the mechanical and dynamic mechanical properties of crosslinked fluorocarbon (FKM) rubber, natural rubber (NR), ethylene propylene diene monomer (EPDM) rubber and nitrile rubber (NBR) has been investigated. The modulus, gel fraction, glass transition temperature ( Tg) and storage modulus increased, while the elongation at the break and the loss tangent (tan δ) Tg decreased. FKM and NBR vulcanizates have been shown to have EB radiation resistance up to 1500 kGy.

  15. Uptake of trifluoroacetate by Pinus ponderosa via atmospheric pathway

    NASA Astrophysics Data System (ADS)

    Benesch, J. A.; Gustin, M. S.

    Trifluoroacetate (TFA, CF 3COO -), a break down product of hydro(chloro)-fluorocarbons (HFC/HCFCs), has been suggested to contribute to forest decline syndrome. To investigate the possible effects, Pinus ponderosa was exposed to TFA applied as mist (150 and 10,000 ng l -1) to foliar surfaces. Needles accumulated TFA as a function of concentration and time. However, no adverse physiological responses, as plant morphology, photosynthetic and conductance rates, were observed at the TFA concentrations used in this study.

  16. Antisoiling Coatings for Solar-Energy Devices

    NASA Technical Reports Server (NTRS)

    Cuddihy, E. F.; Willis, P.

    1986-01-01

    Fluorocarbons resist formation of adherent deposits. Promising coating materials reduce soiling of solar photovoltaic modules and possibly solar thermal collectors. Contaminating layers of various degrees of adherence form on surfaces of devices, partially blocking incident solar energy, reducing output power. Loose soil deposits during dry periods but washed off by rain. New coatings help prevent formation of more-adherent, chemically and physically bonded layers rain alone cannot wash away.

  17. The registration of signals from the nuclei other than protons at 0.5 T MRI scanner

    NASA Astrophysics Data System (ADS)

    Anisimov, N.; Volkov, D.; Gulyaev, M.; Pavlova, O.; Pirogov, Yu

    2016-02-01

    The practical aspects of the adaptation of the medical MRI scanner for multinuclear applications are considered. Examples of high resolution NMR spectra for nuclei 19F, 31P, 23Na, 11B, 13C, 2H, and also NQR spectrum for 35Cl are given. Possibilities of MRI for nuclei 19F, 31P, 23Na, 11B are shown. Experiments on registration of signals 19F from the fluorocarbons injected in laboratory animals are described.

  18. Experimental Study on Evaporation Heat Transfer of Ammonia Flowing inside a Horizontal Internally Spirally Grooved Tube

    NASA Astrophysics Data System (ADS)

    Momoki, Satoru; Arima, Hirofumi; Yamaguchi, Tomohiko; Shigechi, Toru

    This paper presents the experimental results on flow boiling heat transfer of ammonia inside a horizontal internally spirally grooved steel tube with 12mm in averaged inner diameter. Experimental conditions are 40 to 80kg/(m2s) in mass velocity, about 0.7MPa in pressure, and 0 to 20 kW/m2 in heat flux. Measured values on frictional pressure drop in adiabatic condition were correlated by Higashiiue's correlation, which was developed based on the experimental results with fluorocarbon refrigerants. On the measured heat transfer coefficients, very little significant effect of heat flux was found even in the small mass velocity condition, and also smaller influence of mass flux was observed than expected from the forced convection heat transfer theory. The measured heat transfer coefficients were compared with the predicted values by the author's previously developed correlation for fluorocarbon refrigerants,and this equation could not predict heat transfer coefficients of ammonia well. The trends of circumferential distribution of wall temperature in high quality region were different from those observed in the case of fluorocarbon refrigerants. In high quality region, annular mist flow regime appears instead of ordinary annular flow regime.

  19. Sensitivity of an atmospheric photochemistry model to chlorine perturbations including consideration of uncertainty propagation

    NASA Technical Reports Server (NTRS)

    Stolarski, R. S.; Douglass, A. R.

    1986-01-01

    Models of stratospheric photochemistry are generally tested by comparing their predictions for the composition of the present atmosphere with measurements of species concentrations. These models are then used to make predictions of the atmospheric sensitivity to perturbations. Here the problem of the sensitivity of such a model to chlorine perturbations ranging from the present influx of chlorine-containing compounds to several times that influx is addressed. The effects of uncertainties in input parameters, including reaction rate coefficients, cross sections, solar fluxes, and boundary conditions, are evaluated using a Monte Carlo method in which the values of the input parameters are randomly selected. The results are probability distributions for present atmosheric concentrations and for calculated perturbations due to chlorine from fluorocarbons. For more than 300 Monte Carlo runs the calculated ozone perturbation for continued emission of fluorocarbons at today's rates had a mean value of -6.2 percent, with a 1-sigma width of 5.5 percent. Using the same runs but only allowing the cases in which the calculated present atmosphere values of NO, NO2, and ClO at 25 km altitude fell within the range of measurements yielded a mean ozone depletion of -3 percent, with a 1-sigma deviation of 2.2 percent. The model showed a nonlinear behavior as a function of added fluorocarbons. The mean of the Monte Carlo runs was less nonlinear than the model run using mean value of the input parameters.

  20. Synthesis and properties control of fluorinated organic-inorganic hybrid films

    NASA Astrophysics Data System (ADS)

    Yu, Qingjie; Xu, Jianming; Han, Yuanyuan

    2011-12-01

    Fluorinated organic-inorganic hybrid films were prepared by free-radical random copolymerization and sol-gel process through dodecafluoroheptyl methacrylate (DFMA), vinyltriethoxysilane (VTES), and tetramethoxysilane (TMOS). It was found that the prepared fluorinated organic-inorganic hybrid film was very hydrophobic and exhibits excellent water repellency. Hydrophobic fluorocarbon side chains were preferentially enriched to the outermost layer at the interface of coating film-air, and three layers probably exist in the coating films. The fluorinated hybrid films possessed fluorocarbon side chains orient toward the air originating from DFMA as the top layer, hydrocarbon backbone chain originating from vinyl polymerization as the middle layer, and silica network originating from the hydrolysis and condensation of siloxane as the bottom layer. It demonstrated that most of TMOS added might be arranged to the bottom layer of the fluorinated hybrid films, and had a slight impact on the enrichment of fluorocarbon side chains of the outermost layer. However, the useful properties of the fluorinated organic-inorganic hybrid films such as thickness and corrosion resistant can be significantly improved by the increase of TMOS content.

  1. Detection of Chamber Conditioning Through Optical Emission and Impedance Measurements

    NASA Technical Reports Server (NTRS)

    Cruden, Brett A.; Rao, M. V. V. S.; Sharma, Surendra P.; Meyyappan, Meyya; Arnold, Jim (Technical Monitor)

    2000-01-01

    During oxide etch processes, buildup of fluorocarbon residues on reactor sidewalls can cause run-to-run drift and will necessitate some time for conditioning and seasoning of the reactor. Though diagnostics can be applied to study and understand these phenomena, many of them are not practical for use in an industrial reactor. For instance, measurements of ion fluxes and energy by mass spectrometry show that the buildup of insulating fluorocarbon films on the reactor surface will cause a shift in both ion energy and current in an argon plasma. However, such a device cannot be easily integrated into a processing system. The shift in ion energy and flux will be accompanied by an increase in the capacitance of the plasma sheath. The shift in sheath capacitance can be easily measured by a common commercially available impedance probe placed on the inductive coil. A buildup of film on the chamber wall is expected to affect the production of fluorocarbon radicals, and thus the presence of such species in the optical emission spectrum of the plasma can be monitored as well. These two techniques are employed on a GEC (Gaseous Electronics Conference) Reference Cell to assess the validity of optical emission and impedance monitoring as a metric of chamber conditioning. These techniques are applied to experimental runs with CHF3 and CHF3/O2/Ar plasmas, with intermediate monitoring of pure argon plasmas as a reference case for chamber conditions.

  2. Surface tension of water in the presence of perfluorocarbon vapors.

    PubMed

    Chernyshev, Vasiliy S; Skliar, Mikhail

    2014-03-28

    Fluorocarbons are highly hydrophobic, biocompatible compounds with a variety of medical applications. Despite significant interest, the study of interfacial properties of fluorocarbons in aqueous systems has received limited attention. In this study, we investigate the influence of perfluoropentane and perfluorohexane vapors on the surface tension of water at room temperature. The results show a substantial decrease in the surface tension of water in the presence of perfluorocarbon vapors. In the investigated range of partial pressures up to the saturation value, a linear correlation between the surface tension and the partial pressure was found. This suggests that an adsorbed perfluorocarbon layer is formed on the surface of water. For comparison, the effect of the perfluorocarbon vapor on the surface tension of methanol was also investigated and a similar dependence was observed. Our results indicate that the stability and dynamic transitions of fluorocarbon colloids, which may be dispersed under physiological conditions as microdroplets, bubbles, or their combination, are likely affected by the composition of liquid and gas phases. PMID:24652374

  3. Pretreatment of Kapton-coated cable for epoxy adhesion

    SciTech Connect

    Carley, J.F.

    1984-01-09

    Preliminary testing of a new system for protecting bonded strain gages that will be attached to the MFTF magnets indicated falling electrical resistance to ground, attributed to the infiltration of moisture. The most likely infiltration route seemed to be along the Kapton lead cable, which has an outer surface of FEP fluorocarbon resin. Samples of the cable were pretreated with a fluorocarbon etchant, Tetra-Etch, for periods of 10, 25, and 40 s at room temperature, followed by rinsing with demineralized water. The treated ends were embedded in the proposed epoxy sealant, Hysol EA 934, a compound containing 70 wt % of asbestos. The tensile-shear stresses required to pull the wires out of these embedments were measured. Results show that the three levels of treatment are equally effective in raising the bond strength from 377 psi for the untreated cable to about twice that, 763 psi. The 40-s exposure to Tetra-Etch appears to have penetrated the 0.5-mil fluorocarbon coating and attacked the Kapton film and the conductor coatings inside it.

  4. Continuous process for producing n-butanol employing anaerobic fermentation

    SciTech Connect

    Levy, S.

    1986-02-04

    This patent describes a continuous process for the production of n-butanol from the starting materials of an anaerobic fermentation. The process consists of: (a) continuously contacting at least one carbohydrate-containing substrate with an n-butanol producing culture in water to effect the fermentation of substrate and form a product mixture consisting of n-butanol; (b) continuously extracting the product mixture from the substrate, the culture and the water by forming a solution of the product mixture with an extraction solvent while substantially avoiding the formation of a solution of the solvent with the substrate, the culture, and the water. The extraction solvent has at least one fluorocarbon solvent selected from the group consisting of fluorocarbons that boil at temperatures between -41/sup 0/C. and +48/sup 0/C., and have vapor pressures at 21/sup 0/C. between 10 PSIA and 165 PSIA. They also have heats of vaporization below 60 calories per gram, and a specific heat below 0.28. They have a surface tension below 20 dynes per centimeter, a viscosity below 0.5 centipoise, a solubility below 1% in water, and a solubility below 0.2% of water in the fluorocarbon; (c) continuously separating the extraction solvent from the product mixture by vaporizing substantially all of the solvent without substantial vaporization of the product mixture, and (d) continuously condensing the vaporized solvent for reuse as an extraction solvent in step (b).

  5. Understanding the structure of hydrophobic surfactants at the air/water interface from molecular level.

    PubMed

    Zhang, Li; Liu, Zhipei; Ren, Tao; Wu, Pan; Shen, Jia-Wei; Zhang, Wei; Wang, Xinping

    2014-11-25

    Understanding the behavior of fluorocarbon surfactants at the air/water interface is crucial for many applications, such as lubricants, paints, cosmetics, and fire-fighting foams. In this study, molecular dynamics (MD) simulations were employed to investigate the microscopic properties of non-ionic fluorocarbon surfactants at the air/water interface. Several properties, including the distribution of head groups, the distribution probability of the tilt angle between hydrophobic tails with respect to the xy plane, and the order parameter of surfactants, were computed to probe the structure of hydrophobic surfactants at the air/water interface. The effects of the monomer structure on interfacial phenomena of non-ionic surfactants were investigated as well. It is observed that the structure of fluorocarbon surfactants at the air/water interface is more ordered than that of hydrocarbons, which is dominated by the van der Waals interaction between surfactants and water molecules. However, replacing one or two CF2 with one or two CH2 group does not significantly influence the interfacial structure, suggesting that hydrocarbons may be promising alternatives to perfluorinated surfactants. PMID:25358083

  6. Mesoporous silica materials with an extremely high content of organic sulfonic groups and their comparable activities with that of concentrated sulfuric acid in catalytic esterification.

    PubMed

    Feng, Ye-Fei; Yang, Xiao-Yu; Di, Yan; Du, Yun-Chen; Zhang, Yong-Lai; Xiao, Feng-Shou

    2006-07-27

    Mesoporous silica materials (HS-JLU-20) with an extremely high content of mercaptopropyl groups have been successfully synthesized using fluorocarbon-hydrocarbon surfactant mixtures through a simple co-condensation approach of tetraethyl orthosilicate (TEOS) and (3-mercaptopropyl)trimethoxysilane (MPTS), which are characterized by X-ray diffraction (XRD), nitrogen adsorption and desorption isotherms, transmission electron microscopy (TEM), CHNS elemental analysis, thermogravimetry analysis (TGA), and (29)Si NMR spectroscopy. The results show that HS-JLU-20 samples with molar ratios of MPTS/(MPTS + TEOS) at 0.5-0.8 in the starting synthetic gels still show their mesostructures, while HS-SBA-15 with the molar ratio of MPTS/(MPTS + TEOS) at 0.50 completely loses its mesostructure in the absence of fluorocarbon surfactant. Possibly, fluorocarbon surfactant containing N(+) species with a positive charge could effectively interact with negatively charged mercapto groups in the synthesis of HS-JLU-20 materials, resulting in the formation of mesoporous silicas with good cross-linking of silica condensation even at an extremely high content of organic mercapto groups. More interestingly, after the treatment with hydrogen peroxide, HSO(3)-JLU-20 materials with an extremely high content of organic sulfonic groups exhibit comparable activity with liquid concentrated sulfuric acid in catalytic esterification of cyclohexanol with acetic acid. PMID:16854112

  7. Hydrophobic Tail Length, Degree of Fluorination and Headgroup Stereochemistry are Determinants of the Biocompatibility of (Fluorinated) Carbohydrate Surfactants

    PubMed Central

    Li, Xueshu; Turnek, Jaroslav; Kntigov, Pavlna; Kudl?kov, Hana; Maek, Josef; Parkin, Sean; Rankin, Stephen E; Knutson, Barbara L; Lehmler, Hans-Joachim

    2009-01-01

    A series of hydrocarbon and fluorocarbon carbohydrate surfactants with different headgroups (i.e., gluco-, galacto- and maltopyranoside) and (fluorinated) alkyl tails (i.e., C7 and C14 to C19) was synthesized to investigate trends in their cytotoxicity and haemolytic activity, and how surfactant-lipid interactions of selected surfactants contribute to these two measures of biocompatibility. All surfactants displayed low cytotoxicity (EC50 = 25 to > 250 ?M) and low haemolytic activity (EC50 = 0.2 to > 3.3 mM), with headgroup structure, tail length and degree of fluorination being important structural determinants for both endpoints. The EC50 values of hydrocarbon and fluorocarbon glucopyranoside surfactants displayed a cut-off effect (i.e., a maximum with respect to the chain length). According to steady-state fluorescence anisotropy studies, short chain (C7) surfactants partitioned less readily into model membranes, which explains their low cytotoxicity and haemolytic activity. Interestingly, galactopyranosides were less toxic compared to glucopyranosides with the same hydrophobic tail. Although both surfactant types only differ in the stereochemistry of the 4-OH group, hexadecyl gluco- and galactopyranoside surfactants had similar apparent membrane partition coefficients, but differed in their overall effect on the phase behaviour of DPPC model membranes, as assessed using steady-state fluorescence anisotropy studies. These observations suggest that highly selective surfactant-lipid interactions may be responsible for the differential cytotoxicity and, possible, haemolytic activity of hydrocarbon and fluorocarbon carbohydrate surfactants intended for a variety of pharmaceutical and biomedical applications. PMID:19481909

  8. Single-column-based absorption process for treating dissolver off-gas

    SciTech Connect

    Eby, R.S.; Little, D.K.; Merriman, J.R.; Stephenson, M.J.

    1982-05-21

    The fluorocarbon absorption process for krypton and xenon removal from dissolver off-gas is based on exploitation of solubility differences which exist among noble gases and other gas-phase constituents in the fluorocarbon solvent dichlorofluoromethane (refrigerant-12). Process performance and reliability have been demonstrated on an engineering scale with over 10 years of pilot plant operation, including testing with /sup 85/Kr, /sup 133/Xe, and /sup 131/I. The culmination of this work is a single-column design which results in a simplified process with improved reliability and lower cost. Data are presented summarizing recent single-column development activities. These include data plots depicting decontamination factor vs feed gas flow rate, DF vs process absorption factor (kG/L), and location of the concentration peak via the solvent flow rate. In general, 99% removal is easily obtainable for Kr, Xe, and CO/sub 2/ while attaining concentration factors on the order of 10/sup 3/ to 10/sup 4/. Further concentration of the Kr product is investigated using solid sorbent and cold trapping technologies. Effective removal of entrained fluorocarbon solvent and CO/sub 2/ from the single-column product stream is demonstrated using 13X and 5A molecular sieves, respectively. Additional separation of Xe is studied using a silver mordenite bed and compared to existing methods using cryogenic charcoal beds or selective cold trap sublimation. Regardless of the method for Xe removal, Kr is ultimately concentrated via a simple cold trap to > 90% purity from a feed gas containing 10 ppM. 14 figures.

  9. Fluorinated monolayers at liquid-liquid and liquid-vapor interfaces

    NASA Astrophysics Data System (ADS)

    Zhang, Zhongjian

    Microscopic structure of several fluorinated monolayers at water-vapor and water-oil interfaces were examined using x-ray specular reflectivity and grazing incidence diffraction (GID) techniques. Grazing incidence x-ray diffraction measurements of monolayers of perfluoro-n-eicosane (F(CFsb2)sb{20}F) and F(CFsb2)sb{m}(CHsb2)sb{n}H (denoted as Fsb{m}Hsb{n}) supported at the air-water interface demonstrated that even without the conventional polar head group, the surfactant molecules are capable of forming ordered in-plane structures defined by hexagonal close packing of the fluorinated blocks of adsorbed molecules due to the stronger chain-chain interaction between fluorocarbon chains than the corresponding hydrocarbons. The specular reflectivity data reveals a hydrocarbon-down, fluorocarbon-up orientation for Fsb{12}Hsb{18}. In contrast to the conventional expectation that soluble surfactants form disordered monolayers at the liquid-liquid interface, the studies on a fluoroalcohol (F(CFsb2)sb{10}(CHsb2)sb2OH) monolayer at water-hexane interface indicate that the surfactants are in a close packed hexagonal phase, similar to the in-plane structure of other fluorocarbon molecules at water-air interface. Above a transition temperature the monolayer is in a low density gas phase. Preliminary study shows that hysteresis effect occurs around the transition temperature. The first measurements of microscopic structure at common high interfacial tension liquid-liquid interfaces such as a simple oil-water (hexane-water) interface is also reported. Thermal expansion coefficient measurements indicate subtle structural differences in these monolayers.

  10. Trace-element modeling of the magmatic evolution of rare-earth-rich carbonatite from the Miaoya deposit, Central China

    NASA Astrophysics Data System (ADS)

    Xu, Cheng; Kynicky, Jindrich; Chakhmouradian, Anton R.; Campbell, Ian H.; Allen, Charlotte M.

    2010-07-01

    Carbonatites are known to contain the highest concentrations of rare-earth elements (REE) among all igneous rocks. The REE distribution of carbonatites is commonly believed to be controlled by that of the rock-forming Ca minerals (i.e., calcite, dolomite, and ankerite) and apatite because of their high modal content and tolerance for the substitution of Ca by light REE (LREE). Contrary to this conjecture, calcite from the Miaoya carbonatite (China), analyzed in situ by laser-ablation inductively-coupled-plasma mass-spectrometry, is characterized by low REE contents (100-260 ppm) and relatively flat chondrite-normalized REE distribution patterns [average (La/Yb) CN = 1.6]. The carbonatite contains abundant REE-rich minerals, including monazite and fluorapatite, both precipitated earlier than the REE-poor calcite, and REE-fluorocarbonates that postdated the calcite. Hydrothermal REE-bearing fluorite and barite veins are not observed at Miaoya. The textural and analytical evidence indicates that the initially high concentrations of REE and P in the carbonatitic magma facilitated early precipitation of REE-rich phosphates. Subsequent crystallization of REE-poor calcite led to enrichment of the residual liquid in REE, particularly LREE. This implies that REE are generally incompatible with respect to calcite and the calcite/melt partition coefficients for heavy REE (HREE) are significantly greater than those for LREE. Precipitation of REE-fluorocarbonates late in the evolutionary history resulted in depletion of the residual liquid in LREE, as manifested by the development of HREE-enriched late-stage calcite [(La/Yb) CN ? 0.7] in syenites associated with the carbonatite. The observed variations of REE distribution between calcite and whole rocks are interpreted to arise from multistage fractional crystallization (phosphates ? calcite ? REE-fluorocarbonates) from an initially REE-rich carbonatitic liquid.

  11. Physicochemical properties of oleic acid-based partially fluorinated gemini surfactants.

    PubMed

    Sakai, Kenichi; Umemoto, Naoki; Aburai, Kenichi; Takamatsu, Yuichiro; Endo, Takeshi; Kitiyanan, Boonyarach; Matsumoto, Mutsuyoshi; Sakai, Hideki; Abe, Masahiko

    2014-01-01

    We have developed oleic acid-based partially fluorinated gemini surfactants with carboxylic acid headgroups. The fluorocarbon chain is covalently bound to the terminal carbonyl group of oleic acid via a -CH(2)CH(2)OCO- unit, and the carboxylic acid headgroups are introduced to the cis double bond of oleic acid via -OCOCH(2)CH(2)- units. The aqueous solution properties of these surfactants were studied at pH 9 in the presence of 10 mmol dm3 NaCl by means of static surface tension, pyrene fluorescence, and dynamic light scattering measurements. The resulting surface tension data demonstrate that the partially fluorinated gemini surfactants exhibit excellent surface activity in their dilute aqueous solutions. In addition, the surfactants are suggested to form micellar aggregates 24 nm in diameter. We also studied the aqueous temperature-concentration phase diagrams of the partially fluorinated gemini surfactants (disodium salts) on the basis of visual observations (through a crossed polarizer), polarized optical microscopy, and small angle X-ray scattering measurements. Several phase states including micellar solution phase, hexagonal phase, bicontinuous cubic phase, and lamellar phase were observed along with the coexistence of these phases in certain regions. Assemblies with lesser positive curvature tend to be formed with increasing surfactant concentration, increasing temperature, and increasing fluorocarbon chain length. A comparison of the phase diagrams of the partially fluorinated and hydrogenated surfactant systems suggests that close molecular packing is inhibited within the assemblies of the partially fluorinated surfactants because of the limited miscibility between the fluorocarbon and hydrocarbon units. To the best of our knowledge, this is the first systematic report focusing on the temperature-concentration phase diagrams of (partially) fluorinated gemini surfactants over a wide range of compositions and temperatures. PMID:24712085

  12. Hydrophobic tail length, degree of fluorination and headgroup stereochemistry are determinants of the biocompatibility of (fluorinated) carbohydrate surfactants.

    PubMed

    Li, Xueshu; Turnek, Jaroslav; Kntigov, Pavlna; Kudlckov, Hana; Masek, Josef; Parkin, Sean; Rankin, Stephen E; Knutson, Barbara L; Lehmler, Hans-Joachim

    2009-10-01

    A series of hydrocarbon and fluorocarbon carbohydrate surfactants with different headgroups (i.e., gluco-, galacto- and maltopyranoside) and (fluorinated) alkyl tails (i.e., C7 and C14 to C19) was synthesized to investigate trends in their cytotoxicity and haemolytic activity, and how surfactant-lipid interactions of selected surfactants contribute to these two measures of biocompatibility. All surfactants displayed low cytotoxicity (EC50 = 25 to >250 microM) and low haemolytic activity (EC50 = 0.2 to >3.3 mM), with headgroup structure, tail length and degree of fluorination being important structural determinants for both endpoints. The EC50 values of hydrocarbon and fluorocarbon glucopyranoside surfactants displayed a "cut-off" effect (i.e., a maximum with respect to the chain length). According to steady-state fluorescence anisotropy studies, short chain (C7) surfactants partitioned less readily into model membranes, which explains their low cytotoxicity and haemolytic activity. Interestingly, galactopyranosides were less toxic compared to glucopyranosides with the same hydrophobic tail. Although both surfactant types only differ in the stereochemistry of the 4-OH group, hexadecyl gluco- and galactopyranoside surfactants had similar apparent membrane partition coefficients, but differed in their overall effect on the phase behaviour of DPPC model membranes, as assessed using steady-state fluorescence anisotropy studies. These observations suggest that highly selective surfactant-lipid interactions may be responsible for the differential cytotoxicity and, possible, haemolytic activity of hydrocarbon and fluorocarbon carbohydrate surfactants intended for a variety of pharmaceutical and biomedical applications. PMID:19481909

  13. Present Status and Issues of Carbon Nanotubes Alighned Growth Using Plasma Process 5. Synthesis of Aligned Carbon Nanowalls Using Radio-Frequency Plasma Enhanced Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Hiramatsu, Mineo; Hori, Masaru

    Carbon nanowalls, self-assembled two-dimensional carbon nanostructures standing vertically on the substrate, were fabricated using capacitively coupled, radio-frequency, fluorocarbon plasma-enhanced chemical vapor deposition assisted by H radical injection. The correlation between carbon nanowall growth and the fabrication conditions was investigated. The morphologies and growth rate of carbon nanowalls were dependent on the types of carbon source gases and the amount of H radicals injected. In addition, straight, aligned carbon nanowalls with regular spacing were fabricated by controlling the radical flow configuration.

  14. The 1980 stratospheric-tropospheric exchange experiment

    NASA Technical Reports Server (NTRS)

    Margozzi, A. P. (Editor)

    1983-01-01

    Data are presented from the Stratospheric-Tropospheric Water Vapor Exchange Experiment. Measurements were made during 11 flights of the NASA U-2 aircraft which provided data from horizontal traverser and samplings in and about the tops of extensive cirrus-anvil clouds produced by overshooting cumulus turrets. Aircraft measurements were made of water vapor, ozone, ambient and cloud top temperature, fluorocarbons, nitrous oxide, nitric acid, aerosols, and ice crystal populations. Balloonsondes were flown about twice daily providing data on ozone, wind fields, pressure and temperature to altitudes near 30 km. Satellite photography provided detailed cloud and cloud top temperature information. Descriptions of individual experiments and detailed compilations of all results are provided.

  15. Effect of hydraulic fluid (MIL-H-83282) on selected commercial O-ring compounds

    NASA Technical Reports Server (NTRS)

    Wood, T. E.; Stone, W. P.

    1978-01-01

    Acrylonitrile and fluorocarbon compounds were evaluated at various temperatures and time intervals in samples of the fluid obtained from three qualified suppliers. It was concluded that both polymers can function in hydraulic fluids within the conditions defined by this study. Hydraulic fluid from each manufacturer was similar in its effect upon each given O-ring material, with one exception. Similarly, there were no striking differences in the resistance of O-rings of the same generic rubber type when provided by the different manufacturers.

  16. Viscoelastic properties of elastomeric materials for O-ring applications

    NASA Technical Reports Server (NTRS)

    Bower, Mark V.

    1989-01-01

    Redesign of the Space Shuttle Solid Rocket Booster necessitated re-evaluation of the material used in the field joint O-ring seals. This research project was established to determine the viscoelastic characteristics of five candidate materials. The five materials are: two fluorocarbon compounds, two nitrile compounds, and a silicon compound. The materials were tested in a uniaxial compression test to determine the characteristic relaxation functions. These tests were performed at five different temperatures. A master material curve was developed for each material from the experimental data. The results of this study are compared to tensile relaxation tests. Application of these results to the design analysis is discussed in detail.

  17. Methods for study of cardiovascular adaptation of small laboratory animals during exposure to altered gravity. [hypothermia for cardiovascular control and cancer therapy

    NASA Technical Reports Server (NTRS)

    Popovic, V.

    1973-01-01

    Several new techniques are reported for studying cardiovascular circulation in small laboratory animals kept in metabolic chambers. Chronical cannulation, miniaturized membrane type heart-lung machines, a prototype walking chamber, and a fluorocarbon immersion method to simulate weightlessness are outlined. Differential hypothermia work on rat cancers provides localized embedding of radionuclides and other chemotherapeutical agents in tumors and increases at the same time blood circulation through the warmed tumor as compared to the rest of the cold body. Some successful clinical applications of combined chemotherapy and differential hypothermia in skin cancer, mammary tumors, and brain gliomas are described.

  18. Thermal chemiluminescence from ?-irradiated polytetrafluoroethylene and its emission mechanism: Kinetic analysis and bond dissociation energy of fluoroperoxide group

    NASA Astrophysics Data System (ADS)

    Yamada, Emi; Noguchi, Tsuyoshi; Akai, Nobuyuki; Ishii, Hiroshi; Satoh, Chikahiro; Hironiwa, Takayuki; Millington, Keith R.; Nakata, Munetaka

    2014-11-01

    Temperature dependence of the time evolution of chemiluminescence intensity from ?-irradiated polytetrafluoroethylene was examined by heating isothermally in the range of 150 and 200 C. Kinetic analysis was carried out to estimate the rate constants, from which the dissociation energy of the Osbnd O bond in the fluoroperoxide group was determined to be 97 4 kJ mol-1, being consistent with the corresponding value for small fluorocarbon model systems obtained by quantum chemical calculations. This strongly supports the emission mechanism [sbnd CF(OOF)sbnd CF2sbnd ? sbnd COsbnd CF2sbnd + OF2 + h?] proposed in our previous paper to explain chemiluminescence from the ?-irradiated polytetrafluoroethylene.

  19. Fabrication of superhydrophobic surfaces with poly(furfuryl alcohol)/multi-walled carbon nanotubes composites

    NASA Astrophysics Data System (ADS)

    Men, Xue-Hu; Zhang, Zhao-Zhu; Song, Hao-Jie; Wang, Kun; Jiang, Wei

    2008-02-01

    Superhydrophobic films of poly(furfuryl alcohol)/multi-walled carbon nanotubes (PFA/MWNTs) composites have been obtained by using fluorocarbon-modified MWNTs (MWNT-OOCC 7F 15), PFA, and PTFE with a simple preparation method. The prepared films showed both high contact angle and small sliding angle for water droplets. The chemical compositions and microstructures of the resultant film surfaces were also investigated by means of infrared spectroscopy, X-ray photoelectron spectroscopy, and field emission scanning electron microscope, respectively. Both the formed multiscale roughness structures and the lower surface energy play an important role in creating the superhydrophobic surfaces of PFA/MWNTs composites.

  20. Characterization of elastomeric materials with application to design

    NASA Technical Reports Server (NTRS)

    Bower, Mark V.

    1986-01-01

    Redesign of the Space Shuttle Solid Booster has necessitated re-evaluation of the material used in the field joint O-ring seals. The viscoelastic characteristics of five candidate materials were determined. The five materials are: two fluorocarbon compounds, two nitrile compounds, and a silicon compound. The materials were tested in a uniaxial compression test to determine the characteristic relaxation functions. These tests were performed at five different temperatures. A master material curve was developed for each material from the experimental data. The results are compared to tensile relaxation tests. Application of these results to the design analysis is discussed in detail.

  1. Applications of Electron Energy Loss Spectroscopies to the Study of Surface Chemistry

    NASA Astrophysics Data System (ADS)

    Dai, Qing

    Two different kinds of electron energy loss spectroscopies have been used in this thesis to the study of surface chemistry. In the first part of the thesis which includes the first four chapters, Extended Electron Energy Loss Fine Structure (EXELFS) has been used to study the bonding of (1) oxygen atom in NiO film grown on Ni(100) and Ni(110) surface and (2) nitrogen atom overlayer on Cu(100) and Cu(110) surfaces. EXELFS spectra obtained from the K-level of oxygen in NiO film grown on both the Ni(100) and Ni(110) surfaces reveal that the NiO films grown on both surfaces have the same structure as bulk NiO. The Ni-O bond lengths are 2.08 A in both cases. EXELFS spectra obtained above the K-edge of nitrogen atoms adsorbed on the Cu(100) (c(2x2) overlayer) and Cu(110) (p(2x3) overlayer) indicate N-Cu bond lengths of 1.84 and 1.81 A for N on Cu(100) and Cu(110) surfaces, respectively. The difference is within the resolution of the experiment and does not indicate significant differences between the two adsorbate systems. In the second part of the thesis, HREELS and TDS measurements have been used to investigate the surface chemistry of straight chain hydrocarbon alcohols (n-C _{rm n}H_ {rm 2n+1}OH, n = 1,2,3,4,5) and fluorocarbon alcohols (C_{rm n}F_{rm 2n+1} CH_2OH, n = 1,2,3) on Ag(110), Cu(100) and Cu(111) surfaces. It has been found that on clean surfaces, both hydrocarbon alcohols and fluorocarbon alcohols adsorb reversibly without dissociation. When Ag or Cu surfaces are pre-covered with atomic oxygen, alcohols (both hydrocarbon and fluorocarbon alcohols) adsorb dissociatively and form alkoxides and water. At higher temperatures, alkoxides decompose into aldehydes and hydrogen. One of the major differences between fluorocarbon and hydrocarbon alcohols is their surface bond alkoxide stability. Fluorinated alkoxides are more stable on Cu and Ag surfaces studied. This has been attributed mostly to the fact that the alkoxide decomposition transition state involves a carbon cation and that fluorination of the alkyl group destabilizes the transition state and therefore increases the decomposition energy barrier.

  2. Branched Hydrocarbon Low Surface Energy Materials for Superhydrophobic Nanoparticle Derived Surfaces.

    PubMed

    Alexander, Shirin; Eastoe, Julian; Lord, Alex M; Guittard, Frdric; Barron, Andrew R

    2016-01-13

    We present a new class of superhydrophobic surfaces created from low-cost and easily synthesized aluminum oxide nanoparticles functionalized carboxylic acids having highly branched hydrocarbon (HC) chains. These branched chains are new low surface energy materials (LSEMs) which can replace environmentally hazardous and expensive fluorocarbons (FCs). Regardless of coating method and curing temperature, the resulting textured surfaces develop water contact angles (?) of ?155 and root-mean-square roughnesses (Rq) ? 85 nm, being comparable with equivalent FC functionalized surfaces (? = 157 and Rq = 100 nm). The functionalized nanoparticles may be coated onto a variety of substrates to generate different superhydrophobic materials. PMID:26641156

  3. Middle-infrared random lasing of Cr 2+ doped ZnSe, ZnS, CdSe powders, powders imbedded in polymer liquid solutions, and polymer films

    NASA Astrophysics Data System (ADS)

    Kim, C.; Martyshkin, D. V.; Fedorov, V. V.; Mirov, S. B.

    2009-05-01

    Room temperature (RT) middle-infrared (Mid-IR) random lasing of chromium- (Cr) doped ZnSe, ZnS, and CdSe powders, powders imbedded in perfluorocarbon liquid polymer solutions, and fluorocarbon polymer films is reported. Laser active powders were prepared without a stage of bulk crystal growth by annealing of starting chemicals (pure, mixed ZnSe:CrSe; ZnS:CrS; CdSe:CrSe). Mixture of the different semiconductor hosts allows tuning oscillation wavelength from 2240 to 2630 nm.

  4. Looming ban on production of CFCs, halons spurs switch to substitutes

    SciTech Connect

    Zurer, P.S. )

    1993-11-15

    The tight time frame is set by the international treaty called the Montreal Protocol on Substances That Deplete the Ozone Layer. The latest revisions to the treaty dictate an end to industrialized countries' production of CFCs, carbon tetrachloride, and methyl chloroform by Jan. 1, 1996. Halons -- brominated fluorocarbons used for fighting fires -- face a production ban Jan. 1, 1994, just seven weeks from now. This paper reviews the status of the substitution products already available and the work being done to improve these substitute products even more, since some carry ozone-depleting chlorine into the atmosphere, even though they are not as damaging as the CFCs they replace.

  5. Selective protection of poly(tetra-fluoroethylene) from effects of chemical etching

    DOEpatents

    Martinez, Robert J. (Albuquerque, NM); Rye, Robert R. (Albuquerque, NM)

    1991-01-01

    A photolithographic method for treating an article formed of polymeric material comprises subjecting portions of a surface of the polymeric article to ionizing radiation; and then subjecting the surface to chemical etching. The ionizing radiation treatment according to the present invention minimizes the effect of the subseuent chemical etching treatment. Thus, selective protection from the effects of chemical etching can be easily provided. The present invention has particular applicability to articles formed of fluorocarbons, such as PTFE. The ionizing radiation employed in the method may comprise Mg(k.alpha.) X-rays or lower-energy electrons.

  6. Elastohydrodynamic film thickness model for heavily loaded contacts

    NASA Technical Reports Server (NTRS)

    Loewenthal, S. H.; Parker, R. J.; Zaretsky, E. V.

    1973-01-01

    An empirical elastohydrodynamic (EHD) film thickness formula for predicting the minimum film thickness occurring within heavily loaded contacts (maximum Hertz stresses above 150,000 psi) was developed. The formula was based upon X-ray film thickness measurements made with synthetic paraffinic, fluorocarbon, Type II ester and polyphenyl ether fluids covering a wide range of test conditions. Comparisons were made between predictions from an isothermal EHD theory and the test data. The deduced relationship was found to adequately reflect the high-load dependence exhibited by the measured data. The effects of contact geometry, material and lubricant properties on the form of the empirical model are also discussed.

  7. Factors affecting the sticking of insects on modified aircraft wings

    NASA Technical Reports Server (NTRS)

    Yi, O.; Chan, R.; Eiss, N. S.; Pingali, U.; Wightman, J. P.

    1988-01-01

    The adhesion of insects to aircraft wings is studied. Insects were collected in road tests in past studies and a large experimental error was introduced caused by the variability of insect flux. The presence of such errors has been detected by studying the insect distribution across an aluminum-strip covered half-cylinder mounted on the top of a car. After a nonuniform insect distribution (insect flux) was found from three road tests, a new arrangement of samples was developed. The feasibility of coating aircraft wing surfaces with polymers to reduce the number of insects sticking onto the surfaces was studied using fluorocarbon elastomers, styrene butadiene rubbers, and Teflon.

  8. Structural and electrochemical characterization of a cerium(IV) hydroxamate complex: implications for the beneficiation of light rare earth ores.

    PubMed

    Lee, Heui Beom; Bogart, Justin A; Carroll, Patrick J; Schelter, Eric J

    2014-05-25

    Reaction of N-phenyl-pivalohydroxamic acid with Ce(III) precursors leads to a homoleptic hydroxamate complex: Ce(IV)[(t)BuC(O)N(O)Ph]4. Electrochemical experiments indicate a significant stabilization of the Ce(IV) cation at Ep,c = -1.20 V versus SCE in the hydroxamate ligand framework. The spontaneous oxidation of Ce(III) in a hydroxamate ligand field is discussed in the context of beneficiation of the light rare earths from the fluorocarbonate mineral bastnsite. PMID:24177048

  9. (Methacrylates to form insulation). Final technical report

    SciTech Connect

    Rasmussen, L.

    1980-05-20

    The use of methacrylates to form the interior foam of a transport insulation was studied. Problems encountered with the methacrylates include its low surface tension, and its slow rate of polymerization. An additional problem was an incompatability between the fluorinated surfactant molecules and the fluorocarbon gas used to blow the foam. Other experimentation involved acrylamide foams using glycerol-ethylene glycol combinations and sodium linolenate. Also investigated was the use of tin oxide coatings which are transported to visible light but reflect infrared light. (BCS)

  10. Unusual excess free energies of mixing in mixtures of partially fluorinated and hydrocarbon surfactants at the air-water interface: correlation with the structure of the layer.

    PubMed

    Jackson, Andrew J; Dong, Chu Chuan; Thomas, Robert K; Penfold, Jeffrey

    2015-01-13

    The air-water interface of three mixtures of partially fluorinated surfactants and hydrocarbon surfactants, C4F9C11H22N(CH3)3Br (fC4hC11TAB) with hexadecyltrimethylammonium bromide (C16TAB), (CF3)2C3F6C10H20N(CH3)3Br (fC5hC10TAB) with C16TAB, and C8F17C6H12N(CH3)3Br (fC8hC6TAB) with C18TAB, have been investigated using surface tension (ST) and neutron reflection (NR). Using the composition of the layer determined by NR, the pseudophase separation model was used to fit the variation of concentration for a specific ST to a free energy of mixing, G(E), that included adjustable quadratic, cubic and quartic terms. In all three cases, G(E) was found to be highly unsymmetrical, being approximately ideal at low surface fractions of hydrocarbon surfactant and repulsive at high fractions with a maximum value of 0.2-0.3RT. The corresponding structure of the layer was also determined by NR and showed that the initial ideal behavior of G(E) probably results from a balance of a gain in energy from a reduced immersion of the fluorocarbon chain, brought about by screening of the fluorocarbon from water by the hydrocarbon surfactant, and a loss from increased fluorocarbon-hydrocarbon repulsion. At higher concentration, there is no space in the layer for further screening and the fluorocarbon-hydrocarbon repulsion leads to the expected positive G(E). The calculated G(E) also indicated that there should be phase separation of the two components in the interface over a bulk composition range of about 60-95% hydrocarbon surfactant. However, experiment indicates no phase separation. It is suggested that there are a number of possible additional negative contributions to G(E) close to a phase transition, which are not possible for a true bulk phase separation, and which prevent surface phase separation unless it is strongly favored. PMID:25490580

  11. Mass spectrometric studies of the electrical breakdown of thin polymer films

    NASA Technical Reports Server (NTRS)

    Kendall, B. R. F.; Rohrer, V. S.; Bojan, V. J.

    1986-01-01

    The composition of the neutral particles released during the electrical breakdown of 50-micron and 75-micron insulating films of the type used on spacecraft exteriors investigated experimentally using a time-of-flight mass spectrometer triggered by the breakdown event. The experimental apparatus is described in detail, and the results are presented in photographs. It is found that the particle flux from Teflon FEP and PFA films comprise mainly fluorocarbon fragments, some with mass 350 amu or greater, but the flux from Kapton oxygen-ion-beam treated Kapton, Tefzel, and Mylar comprises mainly molecules of mass 44 amu or less.

  12. The Design and Synthesis of Highly Branched and Spherically Symmetric Fluorinated Oils and Amphiles

    PubMed Central

    Jiang, Zhong-Xing; Yu, Y. Bruce

    2007-01-01

    A new emulsifier design principle, based on concepts borrowed from protein science, is proposed. Using this principle, a class of highly branched and spherically symmetric fluorinated oils and amphiles has been designed and synthesized, for potential applications in the construction of fluorocarbon nanoparticles. The Mitsunobu reaction was employed as the key step for introducing three perfluoro-tert-butoxyl groups into pentaerythritol derivatives with excellent yields and extremely simple isolation procedures. Due to the symmetric arrangement of the fluorine atoms, each fluorinated oil or amphile molecule gives one sharp singlet 19F NMR signal. PMID:18461118

  13. The Design and Synthesis of Highly Branched and Spherically Symmetric Fluorinated Oils and Amphiles.

    PubMed

    Jiang, Zhong-Xing; Yu, Y Bruce

    2007-05-01

    A new emulsifier design principle, based on concepts borrowed from protein science, is proposed. Using this principle, a class of highly branched and spherically symmetric fluorinated oils and amphiles has been designed and synthesized, for potential applications in the construction of fluorocarbon nanoparticles. The Mitsunobu reaction was employed as the key step for introducing three perfluoro-tert-butoxyl groups into pentaerythritol derivatives with excellent yields and extremely simple isolation procedures. Due to the symmetric arrangement of the fluorine atoms, each fluorinated oil or amphile molecule gives one sharp singlet (19)F NMR signal. PMID:18461118

  14. NASA/GSFC reliability evaluation of high temperature fiber optic cables

    NASA Technical Reports Server (NTRS)

    Sharma, A. K.; Jacobs, G.

    1992-01-01

    A high temperature (200 C rating) fiber-optic cable of fluorocarbon, silica-based glass, and polyimide coating, 100-micron core was evaluated for Goddard Space Flight Center applications. Testing was performed to evaluate attenuation characteristics of the cables during environmental stresses and exposure to Co-60 gamma radiation. The cables passed environmental tests, but after irradiation failed the established delta limit of 3 dB at 10 krads for a wavelength of 850 nm and 100 krads for a wavelength of 1300 nm.

  15. Atomic Resolution Images of Solid-Liquid Interfaces

    NASA Astrophysics Data System (ADS)

    Giambattista, Brian; McNairy, W. W.; Slough, C. G.; Johnson, A.; Bell, L. D.; Coleman, R. V.; Schneir, J.; Sonnenfeld, R.; Drake, B.; Hansma, P. K.

    1987-07-01

    A scanning tunneling microscope (STM) can provide atomic-resolution images of solids covered with a variety of liquids, including cryogenic fluids, both polar and nonpolar solvents, conductive aqueous solutions, oils, and even greases. This short overview includes images of solids covered with liquid nitrogen, liquid helium, paraffin oil, silicone oil, microscope immersion oil, silicone vacuum grease, fluorocarbon grease, glycerol, and salt water. These images show atoms, charge-density waves, grains in an evaporated metal film, and even corrosion processes as they occur in real time. The future includes not only basic research in surface science but also applied research in lithography, lubrication, catalysis, corrosion, electrochemistry, and perhaps even biology.

  16. A New Energy-Efficient and Environmentally Friendly Process to Produce Aluminum

    NASA Astrophysics Data System (ADS)

    Beck, T. R.

    2013-02-01

    The Hall-Heroult process to produce aluminum is more than 125 years old. Larger, more efficient cells have been developed, and process control has improved, but the process is basically unchanged. A new process has been under development since 1990 that promises 20% lower capital cost and 20% lower operating cost and no CO2 or fluorocarbon emissions. A new cell design, new anode and cathode materials, new electrolyte, and new operating conditions are based on experience over the past six decades. The evolution of this technology to its present state is described here.

  17. Investigation of test methods, material properties, and processes for solar cell encapsulants. Encapsulation task of the low-cost silicon solar array project

    NASA Technical Reports Server (NTRS)

    1977-01-01

    During this quarter, flat-plate solar collector systems were considered and six basic construction elements were identified: outer coatings, superstrates, pottants, substrates, undercoats, and adhesives. Materials surveys were then initiated to discover either generic classes or/and specific products to function as each construction element. Cost data included in the surveys permit ready evaluation of each material. Silicones, fluorocarbons, glass, and acrylic polymers have the highest inherent weatherability of materials studied to date. Only acrylics, however, combine low costs, environmental resistance, and potential processability. This class will receive particular emphasis.

  18. Analyses of mixed-hydrocarbon binary thermodynamic cycles for moderate-temperature geothermal resources

    NASA Astrophysics Data System (ADS)

    Demuth, O. J.

    1981-02-01

    Both boiling and supercritical shell-and-tube cycles were considered. The performance of a dual-boiling isobutane cycle supplied by a 280 F hydrothermal resource (corresponding to the 5 MW pilot plant at the Raft River site in Idaho) was selected as a reference. To investigate the effect of resource temperature on the choice of working fluid, several analyses were conducted for a 360 F hydrothermal resource, which is representative of the Heber resource in California. The hydrocarbon working fluids analyzed included methane, ethane, propane, isobutane, isopentane, hexane, heptane, and mixtures of those pure hydrocarbons. For comparison, two fluorocarbon refrigerants were also analyzed.

  19. Telemetry engineering and fabrication alternative soldering techniques for CFC elimination

    SciTech Connect

    Howard, R.V.

    1995-08-01

    In an effort to eliminate the need for chlorinated fluorocarbons (CFCs) for several production assemblies in Telemetry Engineering and Fabrication, an alternate soldering reflow process to replace the current vapor phase system was needed. After analyzing IR, convection, and recovery vapor phase soldering reflow methods, it was discovered that an improved process would result from the implementation of a new convection reflow system. The convection oven reflow method was evaluated by collecting data from visual inspections, shear, push, and cross-section tests on several surface mount devices.

  20. Volcanic contribution of chlorine to the stratosphere: more significant to ozone than previously estimated?

    PubMed

    Johnston, D A

    1980-07-25

    Earlier estimates of the chlorine emission from volcanoes, based upon evaluations of the preeruption magmatic chlorine content, are too low for some explosive volcanoes by a factor of 20 to 40 or more. Degassing of ash erupted during 1976 by Augustine Volcano in Alaska released 525 x 10(6) kilograms of chlorine (+/- 40 percent), of which 82 x 10(6) to 175 x 10(6) kilograms may have been ejected into the stratosphere as hydrogen chloride. This stratospheric contribution is equivalent to 17 to 36 percent of the 1975 world industrial production of chlorine in fluorocarbons. PMID:17831367

  1. Volcanic contribution of chlorine to the stratosphere: more significant to ozone than previously estimated

    SciTech Connect

    Johnston, D.A.

    1980-07-25

    Earlier estimates of the chlorine emission from volcanoes, based upon evaluations of the preeruption magmatic chlorine content, are too low for some explosive volcanoes by a factor of 20 to 40 or more. Degassing of ash erupted during 1976 by Augustine Volcano in Alaska released 525 x 10/sup 6/ kilograms of chlorine (+/- 40%), of which 82 x 10/sup 6/ to 175 x 10/sup 6/ kilograms may have been ejected into the stratosphere as hydrogen chloride. This stratospheric contribution is equivalent to 17 to 36% of the 1975 world industrial production of chlorine in fluorocarbons. 22 references, 1 table.

  2. Controlling phospholipid self-assembly and film properties using highly fluorinated components--fluorinated monolayers, vesicles, emulsions and microbubbles.

    PubMed

    Krafft, Marie Pierre

    2012-01-01

    Use of fluorinated components instead or along with standard phospholipids in film, vesicle, bubble and emulsion engineering, can cause drastic modifications of the formation processes, structure and dynamics, and functional behavior of these systems. Perfluoroalkyl chains provide a powerful driving force for self-assembly and ordering. They allow, for example, obtainment of thermally stable vesicles from single-chain phosphocholine derivatives, tubules from non-chiral amphiphiles, faceted vesicles with fluid bilayer membranes, exceptionally stable and narrowly dispersed emulsions and microbubbles. Contact of a monolayer of DPPC with a fluorocarbon gas modifies the monolayer's phase behavior, suppressing the liquid expanded/liquid condensed transition. Phospholipid absorption kinetics at an air/water interface can be substantially accelerated, and the equilibrium interfacial tension reduced by exposure to a fluorocarbon gas. Perfluoroalkyl chains induce nanocompartmentation in films and membranes, allowing, for example, polymerization within vesicular membranes. Vesicles involving highly fluorinated components generally exhibit stability, permeability, fusion and recognition characteristics, different from those of their hydrogenated analogues. Drastic stabilization can be gained for phospholipid-coated emulsions through a co-surfactant effect of (perfluoroalkyl)alkyl diblocks. Stable, size-controlled, narrowly dispersed populations of microbubbles have been obtained using fluorinated wall and/or internal gas components, allowing progress in the understanding of microbubble physics, and open new application perspectives. PMID:21816205

  3. Analysis and modeling of nucleate boiling in highly-wetting liquids

    SciTech Connect

    Tong, W.

    1989-01-01

    In recent years, the incessant drive towards higher heat flux and power density in nearly all categories of electronic equipment has turned attention to the use of dielectric liquids, such as the Fluoro-Fluorocarbons (Fluorinerts) and the Chloro-Fluorocarbons (Freons) for the thermal control of electronic components. Since these liquids, referred to as highly-wetting liquids, possess some unusual characteristic properties as compared with conventional liquids, it is expected that the boiling process and dominant heat transfer mechanisms of highly-wetting liquids may be different from those of conventional liquids. Nucleate boiling incipience is one of the most important parameters in boiling heat transfer. In the present study, the effect of contact angle and contact angle hysteresis on boiling incipience is investigated; a set of models for predicting the critical bubble radius and the incipience superheat, as well as the superheat excursion, are presented. Analyses of air/gas trapping in microcavities and of the bubble growth process have been used to relate boiling incipience superheat to the maximum value of the inverse bubble radius. Since both Fluorinerts and Freons possess unusually high gas solubility, the effect of dissolved gas on boiling incipience has been investigated. A theoretical analysis and photographic study of bubble flow regimes in nucleate boiling were performed. The results suggest that thermal transport models such as Rohesnow's, based on isolated bubble behavior, may be applicable to nearly the entire range of nucleate boiling of electronic cooling fluids.

  4. Antisoiling technology: Theories of surface soiling and performance of antisoiling surface coatings

    NASA Technical Reports Server (NTRS)

    Cuddihy, E. F.; Willis, P. B.

    1984-01-01

    Physical examination of surfaces undergoing natural outdoor soiling suggests that soil matter accumulates in up to three distinct layers. The first layer involves strong chemical attachment or strong chemisorption of soil matter on the primary surface. The second layer is physical, consisting of a highly organized arrangement of soil creating a gradation in surface energy from a high associated with the energetic first layer to the lowest possible state on the outer surfce of the second layer. The lowest possible energy state is dictated by the physical nature of the regional atmospheric soiling materials. These first two layers are resistant to removal by rain. The third layer constitutes a settling of loose soil matter, accumulating in dry periods and being removed during rainy periods. Theories and evidence suggest that surfaces that should be naturally resistant to the formation of the first two-resistant layers should be hard, smooth, hydrophobic, free of first-period elements, and have the lowest possible surface energy. These characteristics, evolving as requirements for low-soiling surfaces, suggest that surfaces or surface coatings should be of fluorocarbon chemistry. Evidence for the three-soil-layer concept, and data on the positive performance of candidate fluorocarbon coatings on glass and transparent plastic films after 28 months of outdoor exposure, are presented.

  5. Structure of diblock copolymers in supercritical carbon dioxide and critical micellization pressure

    SciTech Connect

    Triolo, R.; Triolo, A.; Triolo, F.; Steytler, D. C.; Lewis, C. A.; Heenan, R. K.; Wignall, G. D.; DeSimone, J. M.

    2000-04-01

    This paper reports a small angle neutron scattering investigation of micelle formation by fluorocarbon-hydrocarbon block copolymers in supercritical CO{sub 2}(sc-CO{sub 2}) at 65 degree sign C. A sharp unimer-micelle transition is obtained due to the tuning of the solvating ability of sc-CO{sub 2} by profiling pressure, so that the block copolymer, in a semidilute solution, finds sc-CO{sub 2} a good solvent at high pressure and a poor solvent at low pressure. At high pressure the copolymer is in a monomeric state with a random coil structure. However, on lowering the pressure, aggregates are formed with a structure similar to aqueous micelles with the hydrocarbon segments forming the core and the fluorocarbon segments forming the corona of the micelle. This unimer-aggregate transition is driven by the gradual elimination of CO{sub 2} molecules solvating the hydrocarbon segments of the polymer. Comparison of these results with related data on the same polymer at different temperatures indicates that the transition is critically related to the density of the solvent. This suggests the definition of a critical micellization density, to our knowledge a new concept in colloid chemistry. (c) 2000 The American Physical Society.

  6. Low-noise polymeric nanomechanical biosensors

    NASA Astrophysics Data System (ADS)

    Calleja, Montserrat; Tamayo, Javier; Nordstrm, Maria; Boisen, Anja

    2006-03-01

    A sensor device based on a single polymer cantilever and optical readout has been developed for detection of molecular recognition reactions without the need of a reference cantilever for subtraction of unspecific signals. Microcantilevers have been fabricated in the photoresist SU-8 with one surface passivated with a thin fluorocarbon layer. The SU-8 surface is sensitized with biological receptors by applying silanization methods, whereas the fluorocarbon surface remains inert to these processes. The thermal and mechanical properties of the chosen materials allow overcoming the main limitations of gold-coated silicon cantilevers: the temperature, pH, and ionic strength cross sensitivities. This is demonstrated by comparing the response of SU-8 cantilevers and that of gold-coated silicon nitride cantilevers to variations in temperature and pH. The sensitivity of the developed polymeric nanomechanical sensor is demonstrated by real-time detection of the human growth hormone with sensitivity in differential surface stress of about 1mN /m.

  7. Hydrosomes: optically trapped water droplets as nano-containers

    NASA Astrophysics Data System (ADS)

    Helmerson, Kristian; Reiner, Joseph E.; Crawford, Alice M.; Jofre, Ana M.; Kishore, Rani B.; Goldner, Lori S.; Tang, Jianyong; Greene, Mark E.; Gilson, Michael

    2007-09-01

    We demonstrate a novel technique for creating, manipulating, and combining femtoliter to attoliter volume chemical containers. Possible uses include creating controlled chemical reactions involving small quantities of reagent, and studying the dynamics of single molecules. The containers, which we call hydrosomes, are surfactant stabilized aqueous droplets in a low index-of-refraction fluorocarbon medium. The index of refraction mismatch between the container and fluorocarbon is such that individual hydrosomes can be optically trapped by single focus laser beams, i.e. optical tweezers. Previous work on single molecules usually involved the tethering of the molecule to a surface, in order to interrogate the molecule for an extended period of time. The use of hydrosomes opens up the possibility for studying free molecules, away from any perturbing surface. We show that this is indeed true in the case of quantitative FRET with RNA. Furthermore, we demonstrate the controlled fusion of two hydrosomes for studying reactions, such as DNA binding kinetics, and single molecule dynamics under non-equilibrium conditions. We also show the applicability of our technique in analytical chemistry, such as for molecule identification and sorting.

  8. Impacts of CF+, CF2+, CF3+, and Ar Ion Beam Bombardment with Energies of 100 and 400 eV on Surface Modification of Photoresist

    NASA Astrophysics Data System (ADS)

    Takeuchi, Takuya; Amasaki, Shinpei; Kondo, Hiroki; Ishikawa, Kenji; Toyoda, Hirotaka; Sekine, Makoto; Kang, Song-Yun; Sawada, Ikuo; Hori, Masaru

    2011-08-01

    Photoresists used in advanced ArF-excimer laser lithography are not tolerant enough for plasma etching processes. Degradation of photoresists during etching processes might cause not only low selectivity, but also line edge roughness (LER) on the sidewalls of etched patterns. For a highly accurate processing, it is necessary to understand the mechanisms of etching photoresists and to construct a new plasma chemistry that realizes a nano scale precise pattern definition. In this study, the modified layers formed on the surface of a photoresist by the bombardment of fluorocarbon ions of CF+, CF2+, and CF3+, and argon (Ar) ions were analyzed by X-ray photoelectron spectroscopy (XPS). The etching yield of the modified steady-state surface was almost dependent on the mass of incident ion species. The surface composition was modified with increasing dosage of each ion species, and reached a specific steady state that was dependent on the ion species. The bombardment of F-rich ion species such as CF2+ and CF3+ resulted in the formation of not only fluorocarbon layers, but also graphite like structures on the surface. On the basis of these results, the surface reaction for the ion-beam-induced modification was discussed.

  9. Synthesis of perfluoroalkylated xylitol ethers and esters: new surfactants for biomedical uses.

    PubMed

    Zarif, L; Greiner, J; Pace, S; Riess, J G

    1990-04-01

    New, well-defined surfactants and cosurfactants were synthesized with the objective of enhancing the stability of fluorocarbon emulsions destined to serve as oxygen carriers for biomedical applications. Monoperfluoroalkylated ethers of xylitol were achieved by addition of perfluoroalkyl iodide on the double bond of a protected xylitol allyl ether in a one-step addition-elimination reaction. Monoesters were obtained specifically on position 5 by treating 1,2:3,4-di-O-isopropylidenexylitol with perfluoroalkylated acid chlorides of various chain lengths in pyridine at room temperature. The products display strong surface activity and produce a remarkable synergistic stabilization of a fluorocarbon/Pluronic F-68 type emulsion. Biocompatibility data are reported, which include in vitro toxicity tests on Namalva cell cultures and hemolysis tests on human blood cells; the latter was found to decrease as the length of the F-alkyl chain increased. IV injection in mice (n = 10) showed that these products were innocuous at 400-1000 mg/kg of body weight. Preliminary exchange-perfusion experiments on rats with an emulsion containing the F-octyl xylitol ether were encouraging. PMID:2319569

  10. Characterization method of hydrophobic anti-icing coatings

    NASA Astrophysics Data System (ADS)

    Morita, Katsuaki; Sakaue, Hirotaka

    2015-11-01

    For anti-icing, supercooled water should be removed before frozen onto the contact surface. We use a hydrophobic coating for anti-icing and introduce the static- and dynamic-evaluation methods. The methods describe the contact surface between the hydrophobic surface and a supercooled-water droplet. The former is based on the contact angle, and the latter is based on the sliding angle. The temperature factor is included in these models to evaluate the hydrophobic coating under the supercooled conditions. Four hydrophobic coatings are experimentally evaluated based on the static- and dynamic evaluation methods: C1-C3 (commercial fluorocarbon coatings), and Jaxa coating (original fluorocarbon coating). These are evaluated under the supercooled conditions of -10 to 0 C. The static-evaluation shows variations in the temperature. However, change in the contact angle by the temperature is relatively small compared to that of the sliding angle for the dynamic evaluation. Only C3 and Jaxa coatings are tolerant to the sliding angle under the supercooled conditions tested. The dynamic evaluation shows that even if the coating is hydrophobic, the dynamic evaluation should be included to understand the characteristic of removal for a supercooled-water droplet.

  11. A study of the cardiac effects of bromochlorodifluoromethane (halon 1211) exposure during exercise

    SciTech Connect

    Kaufman, J.D.; Morgan, M.S.; Marks, M.L.; Greene, H.L.; Rosenstock, L. )

    1992-01-01

    Bromochlorodifluoromethane (halon 1211, a fire extinguisher), like other fluorocarbons, has been linked with ventricular arrhythmias and myocardial depression. Ten healthy firefighters, aged 40-50, were exposed to 1,000 ppm halon while exercising, in a double-blind, placebo-controlled crossover experiment, and were monitored during and after exposure. Complex ectopy (ventricular couplets and idioventricular rhythm) occurred in two subjects with halon, but none with placebo. One subject had 49.5 ventricular premature beats (VPB)/hour during the period of halon exposure and subsequent 8 hours and only 8.7 VPB/hour during the same period of placebo. In addition, 8 of the 10 subjects had a smaller systolic blood pressure rise during exercise with halon than with placebo. None of the observed differences was statistically significant. These results are consistent with findings in other investigations, suggesting that occupational fluorocarbon exposures may be cardiotoxic in certain individuals, although the small sample sizes used in this and other studies have resulted in limited statistical power to demonstrate this effect.

  12. Amphiphilic crescent-moon-shaped microparticles formed by selective adsorption of colloids.

    PubMed

    Kim, Shin-Hyun; Abbaspourrad, Alireza; Weitz, David A

    2011-04-13

    We use a microfluidic device to prepare monodisperse amphiphilic particles in the shape of a crescent-moon and use these particles to stabilize oil droplets in water. The microfluidic device is comprised of a tapered capillary in a theta (θ) shape that injects two oil phases into water in a single receiving capillary. One oil is a fluorocarbon, while the second is a photocurable monomer, which partially wets the first oil drop; silica colloids in the monomer migrate and adsorb to the interface with water but do not protrude into the oil interface. Upon UV-induced polymerization, solid particles with the shape of a crescent moon are formed; removal of fluorocarbon oil yields amphiphilic particles due to the selective adsorption of silica colloids. The resultant amphiphilic microparticles can be used to stabilize oil drops in a mixture of water and ethanol; if they are packed to sufficient surface density on the interface of the oil drop, they become immobilized, preventing direct contact between neighboring drops, thereby providing the stability. PMID:21417254

  13. Optimization of the Properties of Carbon Nanotube-Based Structures by Electron and Ion Beam Irradiation

    NASA Astrophysics Data System (ADS)

    Sinnott, Susan

    2005-03-01

    There is considerable interest in building new nanostructures for electronic devices and incorporating nanostructured fibers and particles into composites. Here, classical molecular dynamics simulations are used to study the production of new carbon nanotube junctions or cross-links through electron irradiation, in addition to the chemical modification of carbon nanotube-based structures and composites through ion and polyatomic ion beam deposition. In particular, electron irradiation is used to produce junctions between carbon nanotubes. The specific reactions that lead to junction-formation and the mechanical and electronic properties of the resulting junctions will be discussed. Additionally, the chemical modification of multi-walled nanotubes, single-walled and multi-walled nanotube bundles, nanopeapods, and nanotube-polymer composites from polyatomic fluorocarbon ions, which are commonly present in low-energy fluorocarbon plasmas, and Ar will be presented. Multi-walled carbon nanotubes usually fail through the so-called ``sword-and-sheath'' mechanism and nanotube-polymer composites often fail through nanotube pullout. In both cases the failure mechanism is due to the weak van der Waals bonds between either the nanotube shells in the multi-walled tube or between the nanotubes and polymer matrix in the composite. The simulation results show that ion beam deposition produces cross-links between shells in multi-walled nanotubes and between otherwise unfunctionalized nanotubes and polymer backbone chains, which ultimately toughens the composites. The conditions that are predicted to be optimum for effective chemical modification of the system will be discussed.

  14. On the etching characteristics and mechanisms of HfO2 thin films in CF4/O2/Ar and CHF3/O2/Ar plasma for nano-devices.

    PubMed

    Lim, Nomin; Efremov, Alexander; Yeom, Geun Young; Kwon, Kwang-Ho

    2014-12-01

    The study of etching characteristics and mechanisms for HfO2 and Si in CF4/O2/Ar and CHF3/O2/Ar inductively-coupled plasmas was carried out. The etching rates of HfO2 thin films as well as the HfO2/Si etching selectivities were measured as functions of Ar content in a feed gas (0-50% Ar) at fixed fluorocarbon gas content (50%), gas pressure (6 mTorr), input power (700 W), bias power (200 W), and total gas flow rate (40 sccm). Plasma parameters as well as the differences in plasma chemistries for CF4- and CHF3-based plasmas were analyzed using Langmuir probe diagnostics and 0-dimensional plasma modeling. It was found that, in both gas systems, the non-monotonic (with a maximum at about 15-20% Ar) HfO2 etching rate does not correlate with monotonic changes of F atom flux and ion energy flux. It was proposed that, under the given set of experimental conditions, the HfO2 etching process is affected by the factors determining the formation and decomposition kinetics of the fluorocarbon polymer layer. These factor are the fluxes of CF(x) (x = 1, 2) radicals, O atoms and H atoms. PMID:25971118

  15. Plasma etching behavior of Y2O3 ceramics: Comparative study with Al2O3

    NASA Astrophysics Data System (ADS)

    Cao, Yu-Chao; Zhao, Lei; Luo, Jin; Wang, Ke; Zhang, Bo-Ping; Yokota, Hiroki; Ito, Yoshiyasu; Li, Jing-Feng

    2016-03-01

    The plasma etching behavior of Y2O3 coating was investigated and compared with that of Al2O3 coating under various conditions, including chemical etching, mixing etching and physical etching. The etching rate of Al2O3 coating declined with decreasing CF4 content under mixing etching, while that of Y2O3 coating first increased and then decreased. In addition, the Y2O3 coating demonstrated higher erosion-resistance than Al2O3 coating after exposing to fluorocarbon plasma. X-ray photoelectron spectroscopy (XPS) analysis confirmed the formations of YF3 and AlF3 on the Y2O3 and Al2O3 coatings, respectively, which acted as the protective layer to prevent the surface from further erosion with fluorocarbon plasma. It was revealed that the etching behavior of Y2O3 depended not only on the surface fluorination but also on the removal of fluoride layer. To analyze the effect of porosity, Y2O3 bulk samples with high density were prepared by spark plasma sintering, and they demonstrated higher erosion-resistances compared with Y2O3 coating.

  16. Structure-Based Design of Dendritic Peptide Bolaamphiphiles for siRNA Delivery

    PubMed Central

    2015-01-01

    Development of safe and effective delivery vectors is a critical challenge for the application of RNA interference (RNAi)-based biotechnologies. In this study we show the rational design of a series of novel dendritic peptide bolaamphiphile vectors that demonstrate high efficiency for the delivery of small interfering RNA (siRNA) while exhibiting low cytotoxicity and hemolytic activity. Systematic investigation into structure–property relationships revealed an important correlation between molecular design, self-assembled nanostructure, and biological activity. The unique bolaamphiphile architecture proved a key factor for improved complex stability and transfection efficiency. The optimal vector contains a fluorocarbon core and exhibited enhanced delivery efficiency to a variety of cell lines and improved serum resistance when compared to hydrocarbon analogues and lipofectamine RNAiMAX. In addition to introducing a promising new vector system for siRNA delivery, the structure–property relationships and “fluorocarbon effect” revealed herein offer critical insight for further development of novel materials for nucleic acid delivery and other biomaterial applications. PMID:26436138

  17. Effect of different binders on mechanical and ballistic properties of boron - viton based fuel rich propellant

    NASA Astrophysics Data System (ADS)

    Verma, Pankaaj; Bhujbal, J. G.; Ghavate, R. B.; Darekar, S. D.; Singh, R. V.

    2013-06-01

    Boron is a preferred metal in air augmented propulsion because of its very high heat of combustion per unit mass and per unit volume. But oxide layer (B2O3) formed on its surface inhibits the combustion of boron. Use of fluorocarbon binder can be a promising approach for the improved ignition of boron. In the present study Fuel Rich Propellant composition based on Boron / Ammonium Perchlorate / vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene terpolymer (Viton-B) as a fluorocarbon binder is processed. The objective of the study is to improve mechanical and ballistic properties of the propellant; Viton-B is partially replaced by other binders like estane, polymethyl metha acrylate, polystyrene and irostic. The different compositions are tested for mechanical properties like ultimate compressive strength (UCS), % Compression and Modulus by Universal Testing Machine following ASTM standard D695-02A; and ballistic properties like pressure exponent value (`n' value) and rate of burning constant value by strand burner technique. It is observed that as Viton is partially replaced; mechanical properties improve; and ballistic properties decrease. From the results, it is concluded that estane can be used as partial replacement of Viton-B, as value of UCS increases by 27% and burn rate & `n' value is comparable with the full Viton-B binder composition.

  18. Radio-frequency gas discharge (RFGD) fluorination of polymers: Protein and cell interactions at RFGD-fluorinated interfaces

    NASA Astrophysics Data System (ADS)

    Kiaei, David; Hoffman, Allan S.; Horbett, Thomas A.

    1995-08-01

    Proteins naturally adsorb at foreign surfaces. Adsorbed proteins on biomaterial surfaces are important to the biocompatibility of medical implants and devices, as well as to uses in biosensors, diagnostics, separations and industrial bioprocesses. There is ample evidence that the composition, organization, and conformations of the proteins adsorbed at a foreign interface are sensitive to the composition, topography, and molecular mobility of the substrate surface. The protein layer can also change in all the above aspects with time. Thus, it is a dynamic, "living" coating whose character is a direct reflection of the character of the substrate surface. Therefore, it is not surprising that many researchers have modified biomaterial surface compositions in order to influence protein absorption and subsequent conformational changes. The gas discharge process is one of the more useful methods for modification of biomaterial surfaces. Surfaces may be ablated (or etched) in a process which removes material and creates a cleaner, but chemically-modified surface. Gas discharge may also be used to deposit a polymer-like coating of a new composition on the surface, such as silicone and fluorocarbon coatings on hydrocarbon polymer surfaces. Certain of these fluorocarbon discharge-deposited polymers have been shown to enhance retention of adsorbed proteins, presumably by increased hydrophobic interactions with the modified substrate. Furthermore, platelet adhesion on such surfaces may be increasingly reduced as the adsorbed protein is increasingly bound to the fluorinated surface. These unusual results and their biologic implications are discussed in this paper.

  19. Detection of Chamber Conditioning by CF4 in the GEC Cell

    NASA Technical Reports Server (NTRS)

    Cruden, Brett A.; Rao, M. V. V. S.; Sharma, S. P.; Meyyappan, M.; Arnold, James (Technical Monitor)

    2001-01-01

    During oxide etch processes, buildup of fluorocarbon residues on reactor sidewalks can cause to drift and will necessitate time for conditioning and cleaning of the reactor. Various measurements in CF4 and Ar plasmas are made in an attempt to identify a metric able to indicate the chamber condition. Mass spectrometry and a Langmuir probe shows that the buildup of fluorocarbon films on the reactor surface causes a decrease in plasma floating potential, plasma potential, and ion energy in argon plasmas. This change in floating potential is also observed in CF4 plasma operation, and occurs primarily during the first hour and a half of plasma operation. A slight rise in electron density is also observed in the argon plasmas. Because the change is seen in an argon plasma, it is indicative of altered physical, not chemical, plasma-surface interactions. Specifically, the insulating films deposited on metal surfaces alter the electromagnetic fields seen by the plasma, affecting various parameters including the floating potential and electron density. An impedance probe placed on the inductive coil shows a slight reduction in plasma impedance due to this rising electron density. The optical emission of several species, including CF, C2, atomic Si and atomic C, is also monitored for changes in density resulting from the buildup of film on the chamber wall. Changes in the optical emission spectrum are comparable to the noise levels in their measurement.

  20. From superamphiphobic to amphiphilic polymeric surfaces with ordered hierarchical roughness fabricated with colloidal lithography and plasma nanotexturing.

    PubMed

    Ellinas, K; Tserepi, A; Gogolides, E

    2011-04-01

    Ordered, hierarchical (triple-scale), superhydrophobic, oleophobic, superoleophobic, and amphiphilic surfaces on poly(methyl methacrylate) PMMA polymer substrates are fabricated using polystyrene (PS) microparticle colloidal lithography, followed by oxygen plasma etching-nanotexturing (for amphiphilic surfaces) and optional subsequent fluorocarbon plasma deposition (for amphiphobic surfaces). The PS colloidal microparticles were assembled by spin-coating. After etching/nanotexturing, the PMMA plates are amphiphilic and exhibit hierarchical (triple-scale) roughness with microscale ordered columns, and dual-scale (hundred nano/ten nano meter) nanoscale texture on the particles (top of the column) and on the etched PMMA surface. The spacing, diameter, height, and reentrant profile of the microcolumns are controlled with the etching process. Following the design requirements for superamphiphobic surfaces, we demonstrate enhancement of both hydrophobicity and oleophobicity as a result of hierarchical (triple-scale) and re-entrant topography. After fluorocarbon film deposition, we demonstrate superhydrophobic surfaces (contact angle for water 168, compared to 110 for a flat surface), as well as superoleophobic surfaces (153 for diiodomethane, compared to 80 for a flat surface). PMID:21351799

  1. Fluorinated microemulsions: A study of the phase behavior and structure

    SciTech Connect

    LoNostro, P.; Choi, S.M.; Chen, S.H.; Ku, C.Y.

    1999-06-24

    Fluorinated surfactants have been studied for their peculiar property to form micellar aggregates in water and oils (hydrocarbons or fluorocarbons) and to produce stable microemulsions. Because of their capacity to dissolve large amounts of gases (such as oxygen and carbon dioxide) and for their characteristic physicochemical properties, fluorocarbons have been tested for specific medical purposes, and their microemulsions are among the most promising candidates for the production of suitable blood substitutes and other biocompatible fluids. The authors have synthesized a new partially fluorinated nonionic surfactant, namely, F(CF{sub 2}){sub 7}-CO-(OCH{sub 2}CH{sub 2}){sub 7.2}OCH{sub 3} (I), that forms stable microemulsions with water and perfluorocarbons such as perfluorooctane (PFO). In this paper the authors describe for the first time the phase behaviors of perfluorooctanoic acid (PFOA) in water/PFH and in water/PFO, and that of ester I in water/PFO. Small-angle neutron-scattering (SANS) experiments provide a detailed description of the microstructure of the H{sub 2}O/PFO/PFOA ternary system.

  2. Preparation and cell growth inhibitory activity of [PtR(2)L(2)] (R=polyfluorophenyl, L(2)=diene, cyclohexane-1,2-diamine (chxn) or cis-(dimethyl sulfoxide)(2)) and the X-ray crystal structure of [Pt(C(6)F(5))(2)(cis-chxn)].

    PubMed

    Cullinane, Carleen; Deacon, Glen B; Drago, Penny R; Hambley, Trevor W; Nelson, Keith T; Webster, Lorraine K

    2002-04-28

    A range of [PtR(2)(chxn)] (R=C(6)F(5), o-HC(6)F(4), p-HC(6)F(4), p-MeOC(6)F(4) or 3,5-H(2)C(6)F(3); chxn=cyclohexane-1,2-diamine) and cis-[PtR(2)(dmso)(2)] (R=C(6)F(5), p-HC(6)F(4) or p-MeOC(6)F(4); dmso=dimethyl sulfoxide) complexes have been prepared from the corresponding [PtR(2)(diene)] (diene=cis,cis-cycloocta-1,5-diene (cod), hexa-1,5-diene (hex), norbornadiene (nbd) or dicyclopentadiene (dcy)) derivatives and have been spectroscopically characterized. A representative crystal structure of [Pt(C(6)F(5))(2)(cis-chxn)] was determined and shows a slightly distorted square planar geometry for platinum with chxn virtually perpendicular to the coordination plane. The biological activity against L1210 and L1210/DDP cell lines of these compounds together with the behaviour of other organoplatinum complexes, [PtR(2)L(2)] (L(2)=ethane-1,2-diamine (en) or cis-(NH(3))(2)) have been determined. Despite the use of relatively inert fluorocarbon anions as leaving groups, moderate-high cell growth inhibitory activity is observed. None of the fluorocarbon complexes displayed any cross resistance with cisplatin. PMID:12062134

  3. Designing novel hybrid materials by one-pot co-condensation: from hydrophobic mesoporous silica nanoparticles to superamphiphobic cotton textiles.

    PubMed

    Pereira, C; Alves, C; Monteiro, A; Magn, C; Pereira, A M; Ibarra, A; Ibarra, M R; Tavares, P B; Arajo, J P; Blanco, G; Pintado, J M; Carvalho, A P; Pires, J; Pereira, M F R; Freire, C

    2011-07-01

    This work reports the synthesis and characterization of mesoporous silica nanoparticles (MSNs) functionalized with tridecafluorooctyltriethoxysilane (F13) and their in situ incorporation onto cotton textiles. The hybrid MSNs and the functional textiles were prepared by a one-pot co-condensation methodology between tetraethylorthosilicate (TEOS) and F13, with hexadecyltrimethylammonium chloride (CTAC) as the template and triethanolamine as the base. The influence of the F13 to TEOS molar ratio (1:10, 1:5 and 1:3) on the nanoparticle morphology, porosity, degree of functionalization, and hydro/oleophobic properties is discussed. The hybrid nanosilicas presented high colloidal stability and were spherical and monodispersed with average particle size of ?45 nm. They also showed high surface areas, large pore volumes, and a wormhole-type mesoporous structure. The increase in the organosilane proportion during the co-condensation process led to a more radially branched wormhole-like mesoporosity, a decrease in the surface area, pore volume, and amount of surface silanol groups, and an enrichment of the surface with fluorocarbon moieties. These changes imparted hydrophobic and oleophobic properties to the materials, especially to that containing the highest F13 loading. Cotton textiles were coated with the F13-MSNs through an efficient and less time-consuming route. The combination between surface roughness and mesoporosity imparted by the MSNs, and the low surface energy provided by the organosilane resulted in superhydrophobic functional textiles. Moreover, the textile with the highest loading of fluorocarbon groups was superamphiphobic. PMID:21615151

  4. Design and chemical synthesis of iodine-containing molecules for application to solar-pumped I* lasers

    NASA Technical Reports Server (NTRS)

    Shiner, C. S.

    1986-01-01

    The design and chemical synthesis of new media for solar pumped iodine molecule lasers are explored. In an effort to prepare an iodo fluorocarbon compound absorbing strongly at 300 nm or above, the synthesis of perfluoro allylic iodides was investigated. These compounds furnish especially stable allylic radicals upon photodissociation. The desired red shift is anticipated in the absorption maximum could correlate with increasing radical stability. This expectation was based upon the analysis, previously reported, of the structures and absorption maxima of compounds studied earlier. A previously unknown substance was prepared, a prototypical target molecule, perfluoro-3-iodocyclopent-1-ene. It was obtained by reaction of perfluorocyclopentene with sulfur trioxide under the influence of antimony pentafluoride catalyst, followed by treatment of the resulting allylic fluorosulfonate with sodium iodide in sulfoland solvent. Preliminary data indicate that the absorption maximum for the iodo fluorocarbon is not shifted significantly to longer wavelength. It is not certain whether this result reflects an unexpected influence of the cyclic structure upon the position of the absorption maximum.

  5. Polyelectrolyte multilayers with perfluorinated phthalocyanine selectively entrapped inside the perfluorinated nanocompartments.

    PubMed

    Kope?, Maciej; Lapok, Lukasz; Laschewsky, Andre; Zapotoczny, Szczepan; Nowakowska, Maria

    2014-03-14

    A novel perfluorinated magnesium phthalocyanine (MgPcF64) was synthesized and employed to probe nanodomains in hydrophobically modified, amphiphilic cationic polyelectrolytes bearing alkyl and/or fluoroalkyl side chains. MgPcF64 was found to be solubilized exclusively in the aqueous solutions of the fluorocarbon modified polycations, occupying the perfluorinated nanocompartments provided, while analogous polyelectrolytes with alkyl side chains forming hydrocarbon nanocompartments could not host the MgPcF64 dye. Multilayer films were fabricated by means of the layer-by-layer (LbL) deposition method using sodium poly(styrene sulfonate) as a polyanion. Linear multilayer growth was confirmed by UV-Vis spectroscopy and spectroscopic ellipsometry. Atomic force microscopy studies indicated that the micellar conformation of the polycations is preserved in the multilayer films. Fluorescence spectroscopy measurements confirmed that MgPcF64 stays embedded inside the fluorocarbon domains after the deposition process. This facile way of selectively incorporating water-insoluble, photoactive molecules into the structure of polyelectrolyte multilayers may be utilized for nanoengineering of ultrathin film-based optoelectronic devices. PMID:24653994

  6. BAC-MP4 Predictions of thermochemical data for C{sub 1} and C{sub 2} stable and radical hydrofluorocarbons and oxidized hydrofluorocarbons

    SciTech Connect

    Zachariah, M.R.; Burgess, D.R. Jr.; Tsang, W.; Westmoreland, P.R.; Melius, C.F.

    1996-05-23

    An ab initio bond additivity corrected quantum chemistry procedure has been applied to the development of a data base for thermochemistry of C/H/F/O species. This information has been used to construct a chemical kinetic mechanism for the prediction of the behavior of fluorocarbons as flame suppressants, with clear applications to plasma and atmospheric chemistry as well. Bond additivity corrected (BAC) Moller-Plesset fourth-order perturbation theory (MP4) calculations have been performed to obtain a large body of thermochemical data on about 100 closed and open shelled fluorocarbon species. For about 70 of these species, literature values for enthalpies of formation were available for comparison to the calculated values. The average difference between the calculated and literature values was about 9 kJ/mol. The results indicate that the BAC-MP4 procedure can provide energies that are comparable in accuracy to most experimentally derived values, at lower computational costs relative to other more computationally expensive ab initio molecular orbital methods. This work provides a substantial data base of thermochemical data for fluorinated hydrocarbons constructed in a self-consistent manner. 41 refs., 2 figs., 10 tabs.

  7. Theoretical prediction of thermochemistry and kinetics of flurocarbons

    SciTech Connect

    Zachariah, M.R.; Burgess, D. Jr.; Tsang, W.

    1995-12-31

    An ab-initio quantum chemistry procedure has been applied to developing a database for thermochemistry and kinetics of C/H/F/O species. This information has been used to construct a chemical kinetic mechanism for the predication of fluorocarbon combustion. Bond-additivity corrected (BAC) Mollet-Plesset many-body perturbation theory (MP4) calculations have been performed to obtain a large body of thermochemical data (over 110 species) on both closed-and-open shell fluorocarbon species. The method relies on the use of ab-initio molecular orbital theory and an energy correction procedure (BAC) applied to each type of chemical bond in the molecule. In addition, data on transition state structures for reactions have also been generated and rate constants based on RRKM analysis have been derived. Comparisons between theory and experiment will be shown for both the thermochemical and kinetic information as well as a discussion of the power and limitations of this procedure in light of other available methods.

  8. Characterization method of hydrophobic anti-icing coatings.

    PubMed

    Morita, Katsuaki; Sakaue, Hirotaka

    2015-11-01

    For anti-icing, supercooled water should be removed before frozen onto the contact surface. We use a hydrophobic coating for anti-icing and introduce the static- and dynamic-evaluation methods. The methods describe the contact surface between the hydrophobic surface and a supercooled-water droplet. The former is based on the contact angle, and the latter is based on the sliding angle. The temperature factor is included in these models to evaluate the hydrophobic coating under the supercooled conditions. Four hydrophobic coatings are experimentally evaluated based on the static- and dynamic evaluation methods: C1-C3 (commercial fluorocarbon coatings), and Jaxa coating (original fluorocarbon coating). These are evaluated under the supercooled conditions of -10 to 0 °C. The static-evaluation shows variations in the temperature. However, change in the contact angle by the temperature is relatively small compared to that of the sliding angle for the dynamic evaluation. Only C3 and Jaxa coatings are tolerant to the sliding angle under the supercooled conditions tested. The dynamic evaluation shows that even if the coating is hydrophobic, the dynamic evaluation should be included to understand the characteristic of removal for a supercooled-water droplet. PMID:26628173

  9. Uv protective coatings for heliostats and the plastic dome. Final technical report

    SciTech Connect

    Baum, B.; Bansleben, E.; McGrath, P.

    1981-11-01

    Fluorocarbon and acrylic coatings and films were explored as a means of preventing uv degradation of: (1) the polyester (Petra A) film used in the heliostat dome, (2) the first surface silvered polyester (Melinex O) heliostat, (3) the first surface silvered float glass heliostat, as well as (4) and with other coatings to prevent silver spotting of the back surface of a superstrate, second surface heliostat mirror. Uv stabilization systems were developed and tested. The coated or laminated structures were evaluated for adhesion, resistance to high humidity and acid vapor degradation, percent transmittance/ reflectance, water spotting (for case 4 above), and uv stability under the RS-4 Sunlamp (wet and dry). Promising materials were subjected to accelerated outdoor exposure at Desert Sunshine Testing (DSET) in Arizona. Specific uv stabilized acrylic coatings and/or acrylic or fluorocarbon films offered some protection for the Petra A, silvered Melinex O and first surface silvered float glass against weathering, or in case 4 moisture, degradation. However, no system was satisfactory for long term outdoor weathering. Phenoxy primers showed initial promise for back surface protection against silver spotting but require further in depth study.

  10. Evaluations of candidate encapsulation designs and materials for low-cost silicon photovoltaic arrays

    NASA Technical Reports Server (NTRS)

    Gaines, G. B.; Carmichael, D. C.; Sliemers, F. A.; Brockway, M. C.; Bunk, A. R.; Nance, G. P.

    1978-01-01

    Three encapsulation designs for silicon photovoltaic arrays based on cells with silk-screened Ag metallization have been evaluated: transparent polymeric coatings over cells laminated between two films or sheets of polymeric materials; cells adhesively bonded to a glass cover with a polymer pottant and a glass or other substrate component. Silicone and acrylic coatings were assessed, together with acrylic sheet, 0.635 mm fiberglass-reinforced polyester sheet, 0.102 mm polycarbonate/acrylic dual-layer film, 0.127 mm fluorocarbon film, soda-lime glass, borosilicate glass, low-iron glass, and several adhesives. The encapsulation materials were characterized by light transmittance measurements, determination of moisture barrier properties and bond strengths, and by the performance of cells before and after encapsulation. Silicon and acrylic coatings provided inadequate protection. Acrylic and fluorocarbon films displayed good weatherability and acceptable optical transmittance. Borosilicate, low-iron and soda-lime-float glasses were found to be acceptable candidate encapsulants for most environments.

  11. Creation of superhydrophobic stainless steel surfaces by acid treatments and hydrophobic film deposition.

    PubMed

    Li, Lester; Breedveld, Victor; Hess, Dennis W

    2012-09-26

    In this work, we present a method to render stainless steel surfaces superhydrophobic while maintaining their corrosion resistance. Creation of surface roughness on 304 and 316 grade stainless steels was performed using a hydrofluoric acid bath. New insight into the etch process is developed through a detailed analysis of the chemical and physical changes that occur on the stainless steel surfaces. As a result of intergranular corrosion, along with metallic oxide and fluoride redeposition, surface roughness was generated on the nano- and microscales. Differences in alloy composition between 304 and 316 grades of stainless steel led to variations in etch rate and different levels of surface roughness for similar etch times. After fluorocarbon film deposition to lower the surface energy, etched samples of 304 and 316 stainless steel displayed maximum static water contact angles of 159.9 and 146.6°, respectively. However, etching in HF also caused both grades of stainless steel to be susceptible to corrosion. By passivating the HF-etched samples in a nitric acid bath, the corrosion resistant properties of stainless steels were recovered. When a three step process was used, consisting of etching, passivation and fluorocarbon deposition, 304 and 316 stainless steel samples exhibited maximum contact angles of 157.3 and 134.9°, respectively, while maintaining corrosion resistance. PMID:22913317

  12. Possible atmospheric lifetimes and chemical reaction mechanisms for selected HCFCs, HFCs, CH3CCl3, and their degradation products against dissolution and/or degradation in seawater and cloudwater

    NASA Technical Reports Server (NTRS)

    Wine, P. H.; Chameides, W. L.

    1990-01-01

    For a wide variety of atmospheric species including CO2, HNO3, and SO2, dissolution in seawater or cloudwater followed by hydrolysis or chemical reaction represents a primary pathway for removal from the atmosphere. In order to determine if this mechanism can also remove significant amounts of atmospheric chlorofluorocarbons (HCFC's), fluorocarbons (HFC's), and their degradation products, an investigation was undertaken as part of the Alternative Fluorocarbons Environmental Acceptability Study (AFEAS). In this investigation, the rates at which CHCl2CF3 (HCFC-123), CCl2FCH3 (HCFC-141b), CClF2CH3 (HCFC-142b), CHClF2 (HCFC-22), CHClFCF3 (HCFC-124) CH2FCF3 (HFC-134a) CHF2CH3 (HFC-152a), CHF2CF3 (HFC-125), and CH3CCl3 can be dissolved in the oceans and in cloudwater were estimated from the species' thermodynamic and chemical properties using simple mathematical formulations to simulate the transfer of gases from the atmosphere to the ocean or cloudwater. The ability of cloudwater and rainwater to remove gas phase degradation products of these compounds was also considered as was the aqueous phase chemistry of the degradation products. The results of this investigation are described.

  13. Evaluation of cytotoxicity of new semi-fluorinated amphiphiles derived from dimorpholinophosphate.

    PubMed

    Courrier, H M; Krafft, M P; Butz, N; Port, C; Frossard, N; Rmy-Kristensen, A; Mly, Y; Pons, F; Vandamme, Th F

    2003-02-01

    Water-in-fluorocarbon reverse emulsions and microemulsions stabilized by semi-fluorinated amphiphiles derived from the dimorpholinophosphate polar head group, C(n)F(2n+1)(CH(2))(m)OP(O)[N(CH(2)CH(2))(2)O](2) (FnHmDMP), are being investigated as new delivery systems for drugs or genetic materials into the lung. Since information related to the toxicity of fluorinated surfactants is still very limited, we evaluated herein the cytotoxicity of a series of FnHmDMP (n=4, 6, 8 and 10 and m=2, 5, and 11). Both solutions of FnHmDMP in fluorocarbons, and reverse water-in-fluorocarbon emulsions stabilized by FnHmDMP were assessed in order to determine the relation between surfactant structure and cell toxicity, and select the most innocuous emulsifier. A first short-term evaluation on mouse fibroblasts using a viability/cytotoxicity assay indicated that amphiphiles (in solution) with a chain length longer than C12 exhibit less toxicity than amphiphiles with shorter chain. Moreover cytotoxicity decreased also with length of the fluorinated segment. The protective effect of the fluorinated chain was strongly supported by the fact that the hydrogenated analog, C(15)H(31)OP(O)[N(CH(2)CH(2))(2)O](2) (H15DMP), was highly toxic. Qualitative evaluation on human lung epithelial cells (HLEC) using a colorimetric method (Mayer's hematoxylin) confirmed that amphiphiles (in solution) with longer chain were the least cytotoxic. The protective effect of the fluorinated chain appeared, however, to be significant only at low amphiphile concentrations (0.1% w/v). In contrast, at higher concentrations (1% and 5% w/v), the total chain length was the determining factor. Quantitative evaluation of the least cytotoxic amphiphiles using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) method then showed that F10H11DMP (in solution) was harmless until its solubility limit (1% w/v); cell growth was even enhanced due to improved oxygenation provided by the fluorocarbon phase. F8H11DMP exhibited some cytotoxicity at both 1% and 5% w/v, but the toxicity appeared to level off with concentration. Reverse water-in-perfluorooctyl bromide (PFOB) emulsions stabilized by either F10H11DMP or F8H11DMP were found to be non-cytotoxic. In conclusion, the present evaluation indicates that the cytotoxicity of FnHmDMP depends on both total and fluorinated amphiphile chain length, and leads us to select F8H11DMP and F10H11DMP as the less cytotoxic amphiphiles among a series of FnHmDMP compounds. Furthermore, water-in-fluorocarbon emulsions stabilized with F8H11DMP and F10H11DMP appeared to be non-cytotoxic towards HLEC in culture. PMID:12437963

  14. Cardiotoxicity of Freon among refrigeration services workers: comparative cross-sectional study

    PubMed Central

    2009-01-01

    Background Freon includes a number of gaseous, colorless chlorofluorocarbons. Although freon is generally considered to be a fluorocarbon of relatively low toxicity; significantly detrimental effects may occur upon over exposure. The purpose of the present study is to investigate whether occupational exposure to fluorocarbons can induce arterial hypertension, myocardial ischemia, cardiac arrhythmias, elevated levels of plasma lipids and renal dysfunction. Methods This comparative cross-sectional study was conducted at the cardiology clinic of the Suez Canal Authority Hospital (Egypt). The study included 23 apparently healthy male workers at the refrigeration services workshop who were exposed to fluorocarbons (FC 12 and FC 22) and 23 likewise apparently healthy male workers (unexposed), the control group. All the participants were interviewed using a pre-composed questionnaire and were subjected to a clinical examination and relevant laboratory investigations. Results There were no significant statistical differences between the groups studied regarding symptoms suggesting arterial hypertension and renal affection, although a significantly higher percentage of the studied refrigeration services workers had symptoms of arrhythmias. None of the workers had symptoms suggesting coronary artery disease. Clinical examination revealed that the refrigeration services workers had a significantly higher mean pulse rate compared to the controls, though no significant statistical differences were found in arterial blood pressure measurements between the two study groups. Exercise stress testing of the workers studied revealed normal heart reaction to the increased need for oxygen, while sinus tachycardia was detected in all the participants. The results of Holter monitoring revealed significant differences within subject and group regarding the number of abnormal beats detected throughout the day of monitoring (p < 0.001). There were no significant differences detected in the average heart rate during the monitoring period within subject or group. Most laboratory investigations revealed absence of significant statistical differences for lipid profile markers, serum electrolyte levels and glomerular lesion markers between the groups except for cholesterol and urinary ?2-microglobulin (tubular lesion markers) levels which were significantly elevated in freon exposed workers. Conclusions Unprotected occupational exposure to chlorofluorocarbons can induce cardiotoxicity in the form of cardiac arrhythmias. The role of chlorofluorocarbons in inducing arterial hypertension and coronary artery diseases is unclear, although significantly elevated serum cholesterol and urinary ?2-microglobulin levels raise a concern. PMID:19594908

  15. Self-organizing conjugated polymers

    NASA Astrophysics Data System (ADS)

    Hong, Xiaoyong Michael

    2000-10-01

    A general and efficient synthetic route to semifluoroalkyl substituted thiophenes has been developed and a series of 3-semifluoroalkylthiophenes were synthesized. The lengths of the fluorocarbon chain and hydrocarbon spacer between thiophene and fluorocarbon were systematically altered to study their effect on the properties of the resulting polymers. Oxidative polymerization (FeCl3) and electrochemical polymerization of 3-semifluoroalkylthiophenes afforded regiorandom (head-to-tail coupling 70%) homopolymers. The solubility and thermal transition temperatures of the polymers are also dependent on the nature of side chains. The surface properties of the polymers are also a function of the length of fluoroalkyl side chains. From x-ray diffraction, the regiorandom polymers have low crystallinity. Two synthetic methods have been successfully utilized to prepare regioregular poly(3-semifluoroalkylthiophene)s (head-to-tail coupling >90%) and gave identical polymers. The regioregular polymers are highly conjugated and highly ordered. The long side chain substituted polythiophenes form a liquid crystal mesophase between the crystal solid and isotropic liquid phases. To prepare polymers bearing alternating 3-semifluoroalkylthiophene and alkylthiophene units, we developed synthetic methods to 3-semifluoroalkyl-4 '-alkyl-2,2'-bithiophenes. The 3-semifluoroalkyl-4 '-alkyl-2,2'-bithiophenes were polymerized to afford regiorandom and regioregular polymers. Regiorandom polymers have low crystallinity and conjugation. Regioregular, strictly alternating copolymer with 3-semifluoroalkylthiophene and alkylthiophene units are highly conjugated and ordered. The regioregular polymers self-assemble into bilayer structure in solid state due to phase separation between fluorocarbon and hydrocarbon. At high temperatures close to melting transition, the thiophene rings rotate and twist along the molecular axis to give a single layer structure. Methylene bridges were placed between the thiophene and benzene rings of substituted 1,4-bis(2-thienyl)benzene polymers to increase conjugation. Compared to the unbridged polymer, poly(2,5-dioctyl-1,4-bis(2-thienyl)benzene), the methylene bridged polymer has higher conjugation, lower oxidation potential, higher electrical conductivity. The bridged polymer is semicrystalline with a lamellar structure, clearly show melting and crystallization on heating and cooling processes, while the unbridged polymer is amorphous. Thus, introduction of methylene bridge affords a more conjugated polymer with a more rigid, planar backbone which promotes crystallization.

  16. Surface Dipoles: A Growing Body of Evidence Supports Their Impact and Importance.

    PubMed

    Lee, Han Ju; Jamison, Andrew C; Lee, T Randall

    2015-12-15

    Surface dipoles arise from differences in the distribution of electron density of interfacial molecular structures as expressed by charge separation. The direction and magnitude of the associated dipole moments directly impact a variety of interfacial phenomena. For example, the wettability of thin film-coated solid surfaces toward polar contacting liquids can be systematically adjusted by reorienting the direction of an array of interfacial dipoles, while the vector sum total of all of the dipole moments associated with such thin films can be used to tune the work function of a metal. One method of producing such dipole arrays is by coating a surface with a self-assembled monolayer (SAM), which is a thin organic film of amphiphilic adsorbates that spontaneously assemble on a surface. The interfacial properties of SAMs can be menu-selected by choice of adsorbate structure using ?-terminated thiols on gold surfaces as a convenient system for studying and utilizing these properties. In this Account, we describe the impact of an array of oriented surface dipoles upon the interfacial energy of the thin film bearing such an array. Our analysis of these films divides the subject of surface dipole arrays into three types: (1) those directing a well-defined electronegative pole toward the interface, (2) those incorporating an invertable polar group, and (3) those directing a well-defined electropositive pole toward the interface. With regard to the first category, we analyze the impact of permanent dipoles on the wettability of alkanethiolate SAMs generated from adsorbates possessing well-defined transitions between terminal fluorocarbon and underlying hydrocarbon chain segments. The second category covers recent reports of light-responsive SAMs formed from azobenzene-based adsorbates. Finally, the third category explores a unique example of a dipole array that exposes the positive ends of the interfacial dipoles formed from CH3-terminated fluorocarbon tailgroups. Our analysis of the SAMs formed from these carefully crafted adsorbates encompassing several series of fluorocarbon-containing thiols provides support for a conclusion that oriented surface dipoles exert a significant influence on interfacial energetics and wettability. In contrast to the limited distance from the interface that a surface dipole array will have upon contacting liquids, the work function of a thin film reflects the influence of all the polar groups within the film. Therefore, we also explore the change in the substrate work function for n-alkanethiol-modified gold surfaces as a function of molecular length and for other adsorbates as a function of their chemical composition. PMID:26579883

  17. Control of atomic layer degradation on Si substrate

    SciTech Connect

    Nakamura, Y.; Tatsumi, T.; Kobayashi, S.; Kugimiya, K.; Harano, T.; Ando, A.; Kawase, T.; Hamaguchi, S.; Iseda, S.

    2007-07-15

    To develop 32 nm node devices, the degradation of atomic layers on the surface of Si substrates must be controlled. During the etching of a SiO{sub 2} or Si{sub 3}N{sub 4} hard mask or sidewall, the surface of Si is attended due to exposure to fluorocarbon plasma. The authors have quantitatively evaluated the relationship between the energy of incident ions and the thickness of the fluorocarbon polymer for a CH{sub 2}F{sub 2}/CF{sub 4}/Ar/O{sub 2} plasma in a dual frequency CCP system. At a fixed ion energy the thickness of the damage layer (T{sub d}) basically depended on the thickness of the fluorocarbon polymer (T{sub C-F}). When the T{sub C-F} was changed by controlling the O/CF{sub x} gas ratio, T{sub d} had a minimum thickness under the conditions at balance point: P{sub b}, under which the T{sub C-F} was nearly equal to ion penetration depth: D{sub p}. Using molecular dynamics simulation, reaction around the transition from SiO{sub 2} to Si was clarified. The damage was done to the Si before the SiO{sub 2} was completely removed, and the largest T{sub d} was observed when the SiO{sub 2} was etched off. After that, T{sub C-F} began to increase because there was no longer an outflux of O from SiO{sub 2} and the damage decreased as the unstable SiF{sub x} species in the damaged layer desorbed. Once the T{sub C-F} became thicker than the ion penetration depth, the damaged layer got buried and T{sub d} stopped changing. When the ion penetration depth was controlled to be equal to T{sub C-F} in a steady state under low ion energy conditions, the T{sub d} was reduced to less than 1 nm.

  18. Synthesis of new high performance lubricants and solid lubricants

    SciTech Connect

    Lagow, Richard J.

    1993-04-08

    In our second year of funding we began the testing phase of a number of new classes of lubricants. Three different testing collaborations have already begun and a fourth one is In the works with Dr. Stephen Hsu of the National Institute of Standards and Technology. Dr. Hsu also plans to test some of the same materials for us that Shell Development is studying. With Dr. Bill Jones of NASA, we are studying the effects of branching an high temperature lubricant properties in perfluoropolyethers, Initially Bill Jones is comparing the lubrication and physical properties of perfluorotetraglyme and the following two spherical perfluoropolyethers, Note that one contains a fluorocarbon chain and the other one contains a fluorocarbon ether chain. The synthesis of these was reported in the last progress report. With Professor Patricia Thiel of Iowa State University, we are working on studies of perfluoromethylene oxide ethers and have prepared a series of four of these polyethers to study in collaboration with her research group. These perfluoromethylene oxide ethers have the best low temperature properties of any known lubricants. Thiel's group is studying their interactions with metals under extreme conditions. Thirdly, we have also begun an Interaction with W. August Birke of Shell Development Company in Houston for whom we have already prepared samples of the chlorine-substituted fluorocarbon polyether lubricants whose structures appear on page 54 of our research proposal. Each of these four structures is thought to have potential as lubricant additives to motor oils. We also have underway syntheses of other fluorine-containing branched ether lubricants. These new materials which are also promising as antifriction additives for motor oils appear ahead of the perfluoro additives as Appendix I to the progress report. Additionally for Birke and Shell Development we have at their request prepared the novel compound perfluoro salicylic acid. This synthesis was suggested by the Shell staff who thought that esters of perfluoro salicylic acid might be an excellent antifriction additive for motor oil fuels. One of the best additives currently used in motor oils is the hydrocarbon ester of salicylic acid.

  19. Cathodic electrocatalyst layer for electrochemical generation of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Rhodes, Christopher P. (Inventor); Tennakoon, Charles L. K. (Inventor); Singh, Waheguru Pal (Inventor); Anderson, Kelvin C. (Inventor)

    2011-01-01

    A cathodic gas diffusion electrode for the electrochemical production of aqueous hydrogen peroxide solutions. The cathodic gas diffusion electrode comprises an electrically conductive gas diffusion substrate and a cathodic electrocatalyst layer supported on the gas diffusion substrate. A novel cathodic electrocatalyst layer comprises a cathodic electrocatalyst, a substantially water-insoluble quaternary ammonium compound, a fluorocarbon polymer hydrophobic agent and binder, and a perfluoronated sulphonic acid polymer. An electrochemical cell using the novel cathodic electrocatalyst layer has been shown to produce an aqueous solution having between 8 and 14 weight percent hydrogen peroxide. Furthermore, such electrochemical cells have shown stable production of hydrogen peroxide solutions over 1000 hours of operation including numerous system shutdowns.

  20. Study of toxicological evaluation of fire suppressants and extinguishers

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The application of fluorocarbons as possible candidates for fire extinguishers and/or suppressants in confined spaces (such as spacecraft, aircraft, or submarines) was investigated, with special emphasis on their safety to man since they would be inhaled on an almost continuous basis. Short-term exposure experiments, using various animal species, were devised to look at specific parameters in order to determine which of the candidate compounds were sufficiently non-toxic to warrant long-term investigations. The following physiologic criteria were examined; tissue distribution, fluoride concentration, effect on mitochondria, microsomes, liposomes, and liver cell nuclei, erythrocyte fragility, clinical chemistry values, hematology, pathology, cardiac sensitization, behavioral effects. Various rodent species were used for initial investigations, with non-human primate exposures for Freon 116 which was warranted for negative results on rodents. Various types of exposure chambers were used, including closed dynamic chambers allowing for a recirculating atmosphere.

  1. Apparatus and method for atmospheric pressure reactive atom plasma processing for shaping of damage free surfaces

    DOEpatents

    Carr; Jeffrey W. (Livermore, CA)

    2009-03-31

    Fabrication apparatus and methods are disclosed for shaping and finishing difficult materials with no subsurface damage. The apparatus and methods use an atmospheric pressure mixed gas plasma discharge as a sub-aperture polisher of, for example, fused silica and single crystal silicon, silicon carbide and other materials. In one example, workpiece material is removed at the atomic level through reaction with fluorine atoms. In this example, these reactive species are produced by a noble gas plasma from trace constituent fluorocarbons or other fluorine containing gases added to the host argon matrix. The products of the reaction are gas phase compounds that flow from the surface of the workpiece, exposing fresh material to the etchant without condensation and redeposition on the newly created surface. The discharge provides a stable and predictable distribution of reactive species permitting the generation of a predetermined surface by translating the plasma across the workpiece along a calculated path.

  2. Pneumatic instrument gas bleed reduction strategy and practical application

    SciTech Connect

    Adams, M.; Livingston, D.

    1997-12-31

    It has been common practice in the gas industry to power pneumatic instruments from natural gas. It was thought to be practical, inexpensive and harmless. In recent years, however, the view has changed. Methane is a potent greenhouse gas. The escape of methane into the Earth`s atmosphere contributes significantly to global warming. In fact, 18% of all global warming is now attributed to methane. The size of the methane problem is second only to carbon dioxide, and nearly twice the impact of the much discussed chlorinated fluorocarbons. This is a problem created by literally a million tiny flow streams, individually not a concern, but collectively, creating a threat to us all. In addition to the environmental impact, there are also safety, operational and financial impacts to consider. This article deals with cost-effective ways to stop or slow the pneumatic instrument related bleed of natural gas to the atmosphere.

  3. Alternative training agents, Phase 1. Survey of near-term-candidate fire-extinguishing agents and predicting properties of halocarbon mixtures. Volume 1. Final report

    SciTech Connect

    Nimitz, J.S.; Tapscott, R.E.; Skaggs, S.R.; Beeson, H.D.

    1991-02-01

    In this report, 14 compounds are examined as potential near-term candidates for alternative firefighter training agents for streaming applications. This list consists of suitable fluorine-containing compounds(primarily fluorocarbons, hydrofluorocarbons, and hydrochlorofluorocarbons) known to have had significant toxicity testing completed, with bulk production capabilities existing in the past, present, or anticipated near future. Many of these compounds are being produced or considered as replacements for chlorofluorocarbons (CFCs) in refrigeration and foam-blowing applications. The ozone depletion potential, global warming potential, stage of toxicity testing, toxicity, availability, and relative cost of each compound are discussed. Physical and thermodynamic properties and estimated and measured flame suppression concentrations are reported. Those compounds that have low toxicity (with significant testing completed) are available in bulk and have desirable properties are discussed in detail. It is recommended that HCFC-123 be tested both in pure form and in blends as potential replacement training agents. Twelve blends are recommended for fire suppression.

  4. Role of CFC's, substitutes, and other halogenated chemicals in climate change

    SciTech Connect

    den Elzen, M.G.J.; Rotmans, J.; Swart, R.J.

    1990-07-01

    Because of their ozone depleting potential the most important chlorofluorocarbons and halons have been subjected to international control by the Montreal Protocol. Generally these substances play also a significant role in the greenhouse effect. For the implementation of the Montreal agreement measures have to be taken, including conservation, recycling and the application of alternative products. Presently a complete phase out of the regulated CFCs is being negotiated. The feasibility of such a phase out is suggested to be dependent on the development of alternative halocarbons, notably the partly halogenated chlorofluorocarbons (HCFCs) and fluorocarbons (HFCs). Also other existing ozone depleting substances have been brought into the discussion: carbon tetrachloride and methylchloroform. The report evaluates the consequences of different policies with respect to these nonregulated products for climate change.

  5. The importance of the Montreal Protocol in protecting climate

    PubMed Central

    Velders, Guus J. M.; Andersen, Stephen O.; Daniel, John S.; Fahey, David W.; McFarland, Mack

    2007-01-01

    The 1987 Montreal Protocol on Substances that Deplete the Ozone Layer is a landmark agreement that has successfully reduced the global production, consumption, and emissions of ozone-depleting substances (ODSs). ODSs are also greenhouse gases that contribute to the radiative forcing of climate change. Using historical ODSs emissions and scenarios of potential emissions, we show that the ODS contribution to radiative forcing most likely would have been much larger if the ODS link to stratospheric ozone depletion had not been recognized in 1974 and followed by a series of regulations. The climate protection already achieved by the Montreal Protocol alone is far larger than the reduction target of the first commitment period of the Kyoto Protocol. Additional climate benefits that are significant compared with the Kyoto Protocol reduction target could be achieved by actions under the Montreal Protocol, by managing the emissions of substitute fluorocarbon gases and/or implementing alternative gases with lower global warming potentials. PMID:17360370

  6. Comparison of Hyperthermal Ground Laboratory Atomic Oxygen Erosion Yields With Those in Low Earth Orbit

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.; Dill, Grace C.; Loftus, Ryan J.; deGroh, Kim K.; Miller, Sharon K.

    2013-01-01

    The atomic oxygen erosion yields of 26 materials (all polymers except for pyrolytic graphite) were measured in two directed hyperthermal radio frequency (RF) plasma ashers operating at 30 or 35 kHz with air. The hyperthermal asher results were compared with thermal energy asher results and low Earth orbital (LEO) results from the Materials International Space Station Experiment 2 and 7 (MISSE 2 and 7) flight experiments. The hyperthermal testing was conducted to a significant portion of the atomic oxygen fluence similar polymers were exposed to during the MISSE 2 and 7 missions. Comparison of the hyperthermal asher prediction of LEO erosion yields with thermal energy asher erosion yields indicates that except for the fluorocarbon polymers of PTFE and FEP, the hyperthermal energy ashers are a much more reliable predictor of LEO erosion yield than thermal energy asher testing, by a factor of four.

  7. Development of a high-efficiency, gas-fired, heat pipe, warm-air heating system

    NASA Astrophysics Data System (ADS)

    Feldman, S.; Becker, F.

    1985-01-01

    With the introduction by Borg-Warner of the Heatpipe Furnace, one of the major goals of this program was achieved. This milestone was reached after a 105,000 Btu/hr, 85 percent efficient manufacturing prototype heat pipe furnace was designed, fabricated, and tested by Thermo Electron. Other prototype units of different capacities were also designed. The prototypes underwent extensive field testing and in-house accelerated life-cycle testing, indicating that they were reliable, safe, and cost-competitive. Specific issues like freeze protection and oil contamination were addressed. Two different prototype ultrahigh-efficiency condensing furnaces were designed, fabricated and tested. One approach utilized a fluorocarbon-filled heat pipe as a secondary-stage heat exchanger; the other used a plate finned tube coil as the heat exchanger.

  8. Electron ionization of open/closed chain isocarbonic molecules relevant in plasma processing: Theoretical cross sections

    SciTech Connect

    Patel, Umang R.; Joshipura, K. N.; Pandya, Siddharth H.; Kothari, Harshit N.

    2014-01-28

    In this paper, we report theoretical electron impact ionization cross sections from threshold to 2000 eV for isocarbonic open chain molecules C{sub 4}H{sub 6}, C{sub 4}H{sub 8}, C{sub 4}F{sub 6} including their isomers, and closed chain molecules c-C{sub 4}H{sub 8} and c-C{sub 4}F{sub 8}. Theoretical formalism employed presently, viz., Complex Scattering Potential-ionization contribution method has been used successfully for a variety of polyatomic molecules. The present ionization calculations are very important since results available for the studied targets are either scarce or none. Our work affords comparison of C{sub 4} containing hydrocarbon versus fluorocarbon molecules. Comparisons of the present ionization cross sections are made wherever possible, and new ionization data are also presented.

  9. Aggregation behavior and total miscibility of fluorinated ionic liquids in water.

    PubMed

    Pereiro, Ana B; Arajo, Joo M M; Teixeira, Fabiana S; Marrucho, Isabel M; Pieiro, Manuel M; Rebelo, Luis Paulo N

    2015-02-01

    In this work, novel and nontoxic fluorinated ionic liquids (FILs) that are totally miscible in water and could be used in biological applications, where fluorocarbon compounds present a handicap because their aqueous solubility (water and biological fluids) is in most cases too low, have been investigated. The self-aggregation behavior of perfluorosulfonate-functionalized ionic liquids in aqueous solutions has been characterized using conductometric titration, isothermal titration calorimetry (ITC), surface tension measurements, dynamic light scattering (DLS), viscosity and density measurements, and transmission electron microscopy (TEM). Aggregation and interfacial parameters have been computed by conductimetry, calorimetry, and surface tension measurements in order to study various thermodynamic and surface properties that demonstrate that the aggregation process is entropy-driven and that the aggregation process is less spontaneous than the adsorption process. The novel perfluorosulfonate-functionalized ILs studied in this work show improved surface activity and aggregation behavior, forming distinct self-assembled structures. PMID:25580898

  10. Hollow Bragg waveguides fabricated by controlled buckling of Si/SiO2 multilayers.

    PubMed

    Epp, E; Ponnampalam, N; Newman, W; Drobot, B; McMullin, J N; Meldrum, A F; DeCorby, R G

    2010-11-22

    We describe integrated air-core waveguides with Bragg reflector claddings, fabricated by controlled delamination and buckling of sputtered Si/SiO2 multilayers. Thin film deposition parameters were tailored to produce a desired amount of compressive stress, and a patterned, embedded fluorocarbon layer was used to define regions of reduced adhesion. Self-assembled air channels formed either spontaneously or upon heating-induced decomposition of the patterned film. Preliminary optical experiments confirmed that light is confined to the air channels by a photonic band-gap guidance mechanism, with loss ~5 dB/cm in the 1550 nm wavelength region. The waveguides employ standard silicon processes and have potential applications in MEMS and lab-on-chip systems. PMID:21164836

  11. A proximity focusing RICH detector for kaon physics at Jefferson lab hall A

    SciTech Connect

    F. Garibaldi; E. Cisbani; S. Colilli; F. Cusanno; S. Frullani; R. Fratoni; F. Giuliani; M. Gricia; M. Iodice; M. Lucentini; L. Pierangeli; F. Santavenere; G.M. Urciuoli; P. Veneroni; G. De Cataldo; R. De Leo; L. Lagamba; E. Nappi; V. Paticchio; J. LeRose; B. Kross; B. Reitz; J. Segal; C. Zorn; H. Breuer

    2003-04-01

    Important information on the LN interaction can be obtained from High Resolution Hypernuclear Spectroscopy experiments with electromagnetic probes. A challenging experiment on electroproduction of hypernuclei is scheduled for 2003 in Hall A at Jefferson Lab. One of the challenges is the high performance particle identification system needed. The signal is expected to be rare compared to the very high pion and proton backgrounds due to the small electron and kaon detection angles. The ''standard'' Hall A PID apparatus (TOF and two aerogel threshold Cherenkov detectors) does not provide sufficient suppression of the background. Simulations and calculations have shown that a RICH detector would solve the problem. A proximity focusing fluorocarbon/CsI detector similar to the ALICE RICH detector has been designed, built, tested and commissioned. The results show that the detector performs as expected.

  12. Development of a high-efficiency, gas-fired, heat-pipe, warm-air heating system. Final report, January 1983-December 1984

    SciTech Connect

    Feldman, S.; Becker, F.

    1985-01-01

    With the introduction by Borg-Warner of the Heatpipe Furnace, one of the major goals of this program was achieved. This milestone was reached after a 105,000 Btu/hr, 85% efficient manufacturing prototype heat-pipe furnace was designed, fabricated, and tested by Thermo Electron. Other prototype units of different capacities were also designed. The prototypes underwent extensive field testing and in-house accelerated life-cycle testing, indicating that they were reliable, safe, and cost-competitive. Specific issues like freeze protection and oil contamination were addressed. Two different prototype ultrahigh-efficiency condensing furnaces were designed, fabricated, and tested. One approach utilized a fluorocarbon-filled heat pipe as a secondary-stage heat exchanger; the other used a plate finned-tube coil as the heat exchanger.

  13. Total reflection X-ray photoelectron spectroscopy as a semiconductor lubricant elemental analysis method

    NASA Astrophysics Data System (ADS)

    Alshehabi, Abbas; Sasaki, Nobuharu; Kawai, Jun

    2015-12-01

    Photoelectron spectra from a typical hard disk storage media device (HDD) were measured at total reflection and non-total reflection at unburnished, acetone-cleaned, and argon-sputtered conditions. F, O, N, and C usually making the upper layer of a typical hard disk medium were detected. Enhancement of the photoelectron emission of the fluorocarbon lubricant was observed at total reflection. Pt and Co were only found by non-total X-ray photoelectron spectroscopy (XPS) because they are constituents of a deeper region than the top and interface regions. Argon-sputtered, ultrasonic acetone-cleaned, and unburnished top layers were compared at total and non-total reflection conditions. Total reflection X-ray photoelectron spectroscopy (TRXPS) is demonstrated to be a powerful tool for storage media lubrication layer chemical state analysis, reliable for industrial quality control application , and reproducible.

  14. Repulsive effects of hydrophobic diamond thin films on biomolecule detection

    NASA Astrophysics Data System (ADS)

    Ruslinda, A. Rahim; Ishiyama, Y.; Penmatsa, V.; Ibori, S.; Kawarada, H.

    2015-02-01

    The repulsive effect of hydrophobic diamond thin film on biomolecule detection, such as single-nucleotide polymorphisms and human immunodeficiency virus type 1 trans-activator of transcription peptide protein detection, was investigated using a mixture of a fluorine-, amine-, and hydrogen-terminated diamond surfaces. These chemical modifications lead to the formation of a surface that effectively resists the nonspecific adsorption of proteins and other biomolecules. The effect of fluorine plasma treatment on elemental composition was also investigated via X-ray photoelectron spectroscopy (XPS). XPS results revealed a fluorocarbon layer on the diamond thin films. The contact angle measurement results indicated that the fluorine-treated diamond thin films were highly hydrophobic with a surface energy value of ?25 mN/m.

  15. Effects of space radiation on thin polymers and nonmetallics

    NASA Technical Reports Server (NTRS)

    Fogdall, L. B.; Cannaday, S. S.; Slemp, W. S.

    1977-01-01

    Advanced materials for various spacecraft systems in the 1980s and 1990s have been evaluated in situ after exposure to space radiation. Emphasis has been placed on materials having little or no previous base of environmental effects data. Applications ranging from earth orbit to near-sun have been covered. High temperature polymers and composites have been included. Silica composites may offer improved reflectance stability compared with metallized fluorocarbons. Directional reflectance properties of FEP are a function of charged particle energy and flux as well as total exposure fluence and material characteristics. Data obtained on polyimides and polyxylylenes under high temperature radiation exposure conditions will be discussed in the context of near-sun solar sailing and rendezvousing.

  16. Manipulating surface wettability and oil absorbency of diatomite depending on processing and ambient conditions

    NASA Astrophysics Data System (ADS)

    Özen, İlhan; Şimşek, Süleyman; Okyay, Gamze

    2015-03-01

    In this study, a diatomite sample, which is a natural inorganic mineral with inherently high water and oil absorption capacity, was subjected to grinding before surface modification. Afterwards, the diatomite surface was modified via facile methods using a fluorocarbon (FC) chemical and stearic acid (SA) in addition to the sol-gel fluorosilanization (FS) process. The water and oil wettability, and oil absorbency properties of the unmodified and modified diatomites were investigated in addition to diatomite characterizations such as chemical content, surface area, particle size distribution, morphology, and modification efficiency. It was revealed that the wettability was changed completely depending on the surface modification agent and the media used, while the oil absorbency property surprisingly did not change. On the other hand, the oil absorbency was worsened by the grinding process, whereas the wettability was not affected.

  17. Spacecraft dielectric material properties and spacecraft charging

    NASA Technical Reports Server (NTRS)

    Frederickson, A. R.; Wall, J. A.; Cotts, D. B.; Bouquet, F. L.

    1986-01-01

    The physics of spacecraft charging is reviewed, and criteria for selecting and testing semiinsulating polymers (SIPs) to avoid charging are discussed and illustrated. Chapters are devoted to the required properties of dielectric materials, the charging process, discharge-pulse phenomena, design for minimum pulse size, design to prevent pulses, conduction in polymers, evaluation of SIPs that might prevent spacecraft charging, and the general response of dielectrics to space radiation. SIPs characterized include polyimides, fluorocarbons, thermoplastic polyesters, poly(alkanes), vinyl polymers and acrylates, polymers containing phthalocyanine, polyacene quinones, coordination polymers containing metal ions, conjugated-backbone polymers, and 'metallic' conducting polymers. Tables summarizing the results of SIP radiation tests (such as those performed for the NASA Galileo Project) are included.

  18. Plasma Reactor Modeling and Validation Experiments

    NASA Technical Reports Server (NTRS)

    Meyyappan, M.; Bose, D.; Hash, D.; Hwang, H.; Cruden, B.; Sharma, S. P.; Rao, M. V. V. S.; Arnold, Jim (Technical Monitor)

    2001-01-01

    Plasma processing is a key processing stop in integrated circuit manufacturing. Low pressure, high density plum reactors are widely used for etching and deposition. Inductively coupled plasma (ICP) source has become popular recently in many processing applications. In order to accelerate equipment and process design, an understanding of the physics and chemistry, particularly, plasma power coupling, plasma and processing uniformity and mechanism is important. This understanding is facilitated by comprehensive modeling and simulation as well as plasma diagnostics to provide the necessary data for model validation which are addressed in this presentation. We have developed a complete code for simulating an ICP reactor and the model consists of transport of electrons, ions, and neutrals, Poisson's equation, and Maxwell's equation along with gas flow and energy equations. Results will be presented for chlorine and fluorocarbon plasmas and compared with data from Langmuir probe, mass spectrometry and FTIR.

  19. Wide Angle, Single Screen, Gridded Square-Loop Frequency Selective Surface for Diplexing Two Closely Separated Frequency Bands

    NASA Technical Reports Server (NTRS)

    Wu, Te-Kao (Inventor)

    1996-01-01

    The design and performance of a wide angle, single screen, frequency selective surface (FSS) with gridded square-loop path elements are described for diplexing closely separated signal bands, for example, X- and Ku-band signals in an Orbiting Very Long Baseline Interferometer (OVLBI) earth station reflector antenna system, as well as other applications such as military and commercial communications via satellites. Excellent agreement is obtained between the predicted and measured results of this FSS design using the gridded square-loop patch elements sandwiched between 0.0889 cm thick tetrafluoroethylene fluorocarbon polymer (PTFE) slabs. Resonant frequency drift is reduced by 1 GHz with an incidence angle from 0 deg normal to 40 deg from normal.

  20. Oil fill procesure for seismic marine streamer

    SciTech Connect

    Buckles, J.J.

    1990-08-21

    This patent describes a method for improving signal quality in urethane foam mounts utilized on hydrophones in conjunction with a seismic streamer. It comprises: purging a urethane foam mount with a fluid miscible with air and hydrocarbonaceous liquid having a selected density which liquid is used to dampen noise in a hydrophone where the fluid is a member selected from the group consisting of carbon dioxide, fluorocarbons, C{sub 1}{minus}C{sub 4} hydrocarbons, and mixtures thereof which member alone substantially displaces air from the streamer; and thereafter filling the seismic streamer with the hydrocarbonaceous liquid which mixes with the fluid and substantially retains the density of the liquid thereby maintaining neutral buoyancy of the streamer, substantially isolating the hydrophones from noise, and improving signal quality.

  1. Restoring Susceptibility Induced MRI Signal Loss in Rat Brain at 9.4 T: A Step towards Whole Brain Functional Connectivity Imaging

    PubMed Central

    Li, Rupeng; Liu, Xiping; Sidabras, Jason W.; Paulson, Eric S.; Jesmanowicz, Andrzej; Nencka, Andrew S.; Hudetz, Anthony G.; Hyde, James S.

    2015-01-01

    The aural cavity magnetic susceptibility artifact leads to significant echo planar imaging (EPI) signal dropout in rat deep brain that limits acquisition of functional connectivity fcMRI data. In this study, we provide a method that recovers much of the EPI signal in deep brain. Needle puncture introduction of a liquid-phase fluorocarbon into the middle ear allows acquisition of rat fcMRI data without signal dropout. We demonstrate that with seeds chosen from previously unavailable areas, including the amygdala and the insular cortex, we are able to acquire large scale networks, including the limbic system. This tool allows EPI-based neuroscience and pharmaceutical research in rat brain using fcMRI that was previously not feasible. PMID:25844644

  2. Development of a custom on-line ultrasonic vapour analyzer/flowmeter for the ATLAS inner detector, with application to gaseous tracking and Cherenkov detectors

    NASA Astrophysics Data System (ADS)

    Bates, R.; Battistin, M.; Berry, S.; Berthoud, J.; Bitadze, A.; Bonneau, P.; Botelho-Direito, J.; Bousson, N.; Boyd, G.; Bozza, G.; Da Riva, E.; Degeorge, C.; DiGirolamo, B.; Doubek, M.; Godlewski, J.; Hallewell, G.; Katunin, S.; Lombard, D.; Mathieu, M.; McMahon, S.; Nagai, K.; Perez-Rodriguez, E.; Rossi, C.; Rozanov, A.; Vacek, V.; Vitek, M.; Zwalinski, L.

    2013-01-01

    Precision sound velocity measurements can simultaneously determine binary gas composition and flow. We have developed an analyzer with custom electronics, currently in use in the ATLAS inner detector, with numerous potential applications. The instrument has demonstrated ~ 0.3% mixture precision for C3F8/C2F6 mixtures and < 10-4 resolution for N2/C3F8 mixtures. Moderate and high flow versions of the instrument have demonstrated flow resolutions of 2% of full scale for flows up to 250 l min-1, and 1.9% of full scale for linear flow velocities up to 15 m s-1 the latter flow approaching that expected in the vapour return of the thermosiphon fluorocarbon coolant recirculator being built for the ATLAS silicon tracker.

  3. The use of atmospheric measurements to constrain model predictions of ozone change from chlorine perturbations

    NASA Technical Reports Server (NTRS)

    Douglass, Anne R.; Stolarski, Richard S.

    1987-01-01

    Atmospheric photochemistry models have been used to predict the sensitivity of the ozone layer to various perturbations. These same models also predict concentrations of chemical species in the present day atmosphere which can be compared to observations. Model results for both present day values and sensitivity to perturbation depend upon input data for reaction rates, photodissociation rates, and boundary conditions. A method of combining the results of a Monte Carlo uncertainty analysis with the existing set of present atmospheric species measurements is developed. The method is used to examine the range of values for the sensitivity of ozone to chlorine perturbations that is possible within the currently accepted ranges for input data. It is found that model runs which predict ozone column losses much greater than 10 percent as a result of present fluorocarbon fluxes produce concentrations and column amounts in the present atmosphere which are inconsistent with the measurements for ClO, HCl, NO, NO2, and HNO3.

  4. Development and evaluation of elastomeric materials for geothermal applications

    NASA Technical Reports Server (NTRS)

    Mueller, W. A.; Kalfayan, S. H.; Reilly, W. W.; Ingham, J. D.

    1978-01-01

    A material for a casing packer for service for 24 hours in a geothermal environment was developed by synthesis of new elastomers and formulation of available materials. Formulation included use of commercial elastomer gumstocks and also crosslinking of plastic (high Tg) materials. Fibrous reinforcement of fluorocarbon rubbers was emphasized. Organic fiber reinforcement did not increase hot properties significantly. Glass fiber reinforcement gave significant increase in tensile properties. Elongation was reduced, and the glass-reinforced composition examined so far did not hold up well in the geothermal environment. Colloidal asbestos fibers were also investigated. A few experiments with polyphenyl ether gave material with low tensile and high compression set. Available high styrene SBR compositions were studied. Work to date suggests that new synthetic polymers will be required for service in geothermal environments.

  5. Burst behavior at a capillary tip: Effect of low and high surface tension.

    PubMed

    Agonafer, Damena D; Lopez, Ken; Palko, James W; Won, Yoonjin; Santiago, Juan G; Goodson, Kenneth E

    2015-10-01

    Liquid retention in micron and millimeter scale devices is important for maintaining stable interfaces in various processes including bimolecular separation, phase change heat transfer, and water desalination. There have been several studies of re-entrant geometries, and very few studies on retaining low surface tension liquids such as fluorocarbon-based dielectric liquids. Here, we study retention of a liquid with very low contact angles using borosilicate glass capillary tips. We analyzed capillary tips with outer diameters ranging from 250 to 840 ?m and measured Laplace pressures up to 2.9 kPa. Experimental results agree well with a numerical model that predicts burst pressure (the maximum Laplace pressure for liquid retention), which is a function of the outer diameter (D) and capillary exit edge radius of curvature (r). PMID:26046980

  6. The 1977 intertropical convergence zone experiment

    NASA Technical Reports Server (NTRS)

    Poppoff, I. G. (Editor); Page, W. A. (Editor); Margozzi, A. P. (Editor)

    1979-01-01

    Data are presented from the 1977 Intertropical Convergence Zone (ITCZ) Experiment conducted in the Panama Canal Zone in July 1977. Measurements were made daily over a 16-day period when the ITCZ moved across the Canal Zone. Two aircraft (Learjet and U-2) flew daily and provided data from horizontal traverses at several altitudes to 21.3 km of ozone, temperature, pressure, water vapor, aerosols, fluorocarbons, methane, nitrous oxide, nitric oxide, and nitric acid. Balloonsondes flown four times per day provided data on ozone, wind fields, pressure, temperature, and humidities to altitudes near 30 km. Rocketsondes provided daily data to altitudes near 69 km. Satellite photography provided detailed cloud information. Descriptions of individual experiments and detailed compilations of all results are provided.

  7. Control of internal and external short circuits in lithium batteries using a composite thermal switch

    NASA Technical Reports Server (NTRS)

    Mcdonald, Robert C.; Pickett, Jerome; Goebel, Franz

    1991-01-01

    A composite material has been developed, consisting of a blend of metal and fluorocarbon particles, which behaves as an electronic conductor at room temperature and which abruptly becomes an insulator at a predetermined temperature. This switching behavior results from the difference in thermal expansion coefficients between the conductive and non-conductive portions of the composite. This material was applied as a thin film between the carbon cathode in Li/SOCl2 cells, and the metallic cathode current collector. Using test articles incorporating this feature it was shown that lithium cells externally heated or internally heated during a short circuit lost rate capability and the ability to overheat well below the melting point of lithium (180 C). Thus, during an internal or external cell short circuit, the potential for thermal runaway involving reactions of molten lithium is avoided.

  8. The effects of specified chemical meals on food intake.

    PubMed

    Koopmans, H S; Maggio, C A

    1978-10-01

    Rats received intragastric infusions of various specified chemical meals and were subsequently tested for a reduction in food intake. A second experiment, using a novel technique, tested for conditioned aversion to the meal infusions. The nonnutritive substances, kaolin clay and emulsified fluorocarbon, had no significant effect on food intake. Infusions of 1 M glucose and 1 M sorbitol reduced feeding behavior, but the 1 M sorbitol infusion also produced a conditioned aversion to flavored pellets paired with the sorbitol infusion, showing that the reduced feeding could have been caused by discomfort. Infusion of a high-fat meal consisting of emulsified triolein mixed with small amounts of sugar and protein or the rat's normal liquid diet, Nutrament, also reduced food intake, and both infusions failed to produce a conditioned aversion. The use of specified meals to understand the chemical basis of satiety requires a sensitive behavioral test to establish that the meal does not cause discomfort or other nonspecific effects. PMID:707387

  9. Electron ionization of open/closed chain isocarbonic molecules relevant in plasma processing: Theoretical cross sections

    NASA Astrophysics Data System (ADS)

    Patel, Umang R.; Joshipura, K. N.; Kothari, Harshit N.; Pandya, Siddharth H.

    2014-01-01

    In this paper, we report theoretical electron impact ionization cross sections from threshold to 2000 eV for isocarbonic open chain molecules C4H6, C4H8, C4F6 including their isomers, and closed chain molecules c-C4H8 and c-C4F8. Theoretical formalism employed presently, viz., Complex Scattering Potential-ionization contribution method has been used successfully for a variety of polyatomic molecules. The present ionization calculations are very important since results available for the studied targets are either scarce or none. Our work affords comparison of C4 containing hydrocarbon versus fluorocarbon molecules. Comparisons of the present ionization cross sections are made wherever possible, and new ionization data are also presented.

  10. The wettability of fluoropolymer surfaces: influence of surface dipoles.

    PubMed

    Lee, Sangwha; Park, Joon-Seo; Lee, T Randall

    2008-05-01

    The wettabilities of fluorinated polymers were evaluated using a series of contacting probe liquids ranging in nature from nonpolar aprotic to polar aprotic to polar protic. Fully fluorinated polymers were wet less than partially fluorinated polymers, highlighting the weak dispersive interactions of fluorocarbons. For partially fluorinated polymers, the interactions between the distributed dipoles along the polymer backbone and the dipoles of the contacting liquids were evaluated using both polar and nonpolar probe liquids. The results demonstrate that the surface dipoles of the fluoropolymers generated by substituting fluorine atoms with hydrogen or chlorine atoms can strongly interact with polar contacting liquids. The wettabilities of the partially fluorinated polymers were enhanced by increasing the density of dipoles across the surfaces and by introducing differentially distributed dipoles. PMID:18393484

  11. Implications of the Montreal Protocol for atmospheric emissions of alternative chemicals. Report for January-March 1988

    SciTech Connect

    Hummel, K.E.; Smith, N.D.; Harmon, D.L.

    1988-08-01

    This paper is about alternative chemicals. The substitution, of less ozone-depleting chemicals wherever it is cost effective and technically feasible, is expected because of anticipated future limitations on production and consumption of the fully halogenated chlorofluorocarbons (CFCs) and halons (fluorocarbons containing bromine atoms) covered by the Montreal Protocol. Certain alternative chemicals (e.g., HCFC-22 and methyl chloroform) are already used in applications other than as CFC substitutes. Projected future consumption of alternative chemicals includes such non-substitution use. Study results indicate that the 50% reduction in weighted CFC/halon consumption (weighted for ozone-depletion potential) required by the Protocol in 1998 could initially be achieved by alternative chemicals alone. However, alternative processes or products not requiring either the controlled substances or their substitute chemicals and/or substantial recovery and reuse of the chemicals would be needed to maintain the 50% level of reduction in the longer term.

  12. Coolant controversy heats up

    SciTech Connect

    Shanley, A.

    1997-11-01

    In 1987, nations of the world banded together under the Montreal Protocol to help protect the earth`s ozone layer. Now, ten years and $2.4 billion in new fluorocarbon R and D later, the ozone hole is still with us, as a black market in illegal chlorofluorocarbons thrives and legal trade in recycled CFCs continues. Unfortunately, each alternative to CFCs poses tradeoffs. Some hydrochlorofluorocarbons present lubricant compatibility problems, and, because they are also somewhat ozone depleting, they`ll be phased out in the US between 2010 and 2030, and earlier in Europe. Chlorine-free hydrofluorocarbons contribute to global warming and some require lubricant changes and retooling, while the processes that make them emit halogenated organics. This paper discusses compatibility, flammability, global warming, and supply problems.

  13. Plasma-assisted surface modification and radical diagnostics

    NASA Astrophysics Data System (ADS)

    Sugai, H.; Yamage, M.; Hikosaka, Y.; Nakano, T.; Toyoda, H.

    1993-05-01

    Plasma-assisted deposition and etching have widely been applied to microelectronics devices in industries as well as to huge vacuum devices in nuclear fusion. A more detailed understanding of plasma processing is essential for development of new techniques for small-scale ( < {1}/{4} ?m ) etching and large-scale ( >10 m) deposition. A scaling law for uniformity of large-scale deposition was found in a simulation experiment of boron coating of fusion devices, using a less hazardous boride B 10H 14 (decaborane). Moreover, boron etching by a fluorocarbon plasma was demonstrated along with a new modeling of surface-coverage effects. Appearance mass spectrometry which is a powerful tool for neutral radical detection, has successfully been applied to a CF 4 containing RF plasma for semiconductor etching. Addition of a small amount of H 2 into CF 4 drastically modified the kinetics of CF 2 and CF 3 radicals as a result of surface processes.

  14. Metal Surface Decontamination by the PFC Solution

    SciTech Connect

    Hui-Jun Won; Gye-Nam Kim; Wang-Kyu Choi; Chong-Hun Jung; Won-Zin Oh

    2006-07-01

    PFC (per-fluorocarbon) spray decontamination equipment was fabricated and its decontamination behavior was investigated. Europium oxide powder was mixed with the isotope solution which contains Co-60 and Cs-137. The different shape of metal specimens artificially contaminated with europium oxide powder was used as the surrogate contaminants. Before and after the application of the PFC spray decontamination method, the radioactivity of the metal specimens was measured by MCA. The decontamination factors were in the range from 9.6 to 62.4. The spent PFC solution was recycled by distillation. Before and after distillation, the turbidity of PFC solution was also measured. From the test results, it was found that more than 98% of the PFC solution could be recycled by a distillation. (authors)

  15. Breakdown and discharge regimes in standard and micrometer size dc discharges

    NASA Astrophysics Data System (ADS)

    koro, N.

    2012-11-01

    In this paper, an overview of our recent experimental studies of the breakdown and operation of non-equilibrium discharges in centimetre and micrometer size geometries is presented. In the centimetre size geometries, we focused on elementary processes and phenomenology in gases used for some of the currently most attractive applications of low temperature plasmas - fluorocarbon gases (CF4, CHClF2) and water vapour. Measurements were performed at electrode separation d = 1.1 cm, in a pressure range from 0.1 to 5 Torr. In the case of micro-discharges, the emphasis was on testing the validity of standard scaling laws and proper determination of scaling parameters pd and j/p2. This was done at electrode gaps of 200 and 500 ?m and pressures of 50 and 20 Torr in argon. The investigation is based on measurements of breakdown potentials (Paschen curves) and Volt-Ampere characteristics, supported by simultaneous ICCD imaging of the discharges.

  16. Fine Contact Hole Etching in Magneto-Microwave Plasma

    NASA Astrophysics Data System (ADS)

    Miyakawa, Yasuhiro; Hashimoto, Jun; Ikegami, Naokatsu; Matsui, Takayuki; Kanamori, Jun

    1994-04-01

    Characteristics of fine contact hole etching have been investigated in hydro-fluorocarbon magneto-microwave plasma focusing on the z component of the gradient of magnetic field at 0.0875 T ( dB/ dz) and peak-to-peak voltage of RF bias (V pp) as parameters. Decrease of dB/ dz drastically decreases the etch rate of boro-phospho silicate glass (BPSG), critical dimension loss (defined as diameter of the top of contact hole minus diameter of the bottom of resist) and selectivity over heavily doped n-type polycrystalline silicon ( n+ poly Si) and resist in fine contact holes. The changes of etching characteristics are correlated with neither F/C ratio nor C1s spectrum of deposited film, but with deposition rate in the region of high V pp, which presumably reflects the change of incident CF m+ ion species with dB/ dz.

  17. Economical Analysis about Ammonia Absorption Refrigeration Plants

    NASA Astrophysics Data System (ADS)

    Takei, Toshitaka

    NH3-H2O absorption refrigeration plant is attractive from each standpoint of electric power saving, non-fluorocarbon and energy saving. The plant can be the economic alternative of power compression refrigeration for evaporation temperature range from 0C to -60C, using suitable waste heat (co-generation system, waste incinerator), oil and natural gas. In the application of the plant, the equipment cost and the COP must be reasonable from economical standpoint. Therefore, the paper shows the following. 1) Necessary heating temparature analysis for absorption plant 2) Equipment cost analysis for heating temperature 3) Equipment cost analysis for COP 4) Number of trays in the rectifying column for COP 5) Equipment cost analysis and COP in two-stage absorption

  18. Adenovirus of ring-necked pheasants: purification and partial characterization of marble spleen disease virus.

    PubMed Central

    Iltis, J P; Daniels, S B

    1977-01-01

    A method for purification of marble spleen disease virus (MSDV) from the spleens of infected turkeys and pheasants is described. It combines chloroform or fluorocarbon extraction with subsequent purification by centrifugation on a cushion of cesium chloride (CsCl). Further purification of MSDV was accomplished with a CsCl equilibrium density gradient. A viral buoyant density of approximately 1.32 to 1.33 g/cm3 was determined. Negative-stain electron microscopy revealed that virus isopycnically banded by CsCl gradient had non-enveloped icosahedral capsids composed of 252 capsomeres. The direct colorimetric diphenylamine assay indicated that MSDV has deoxyribonucleic acid as its nucleic acid. The above evidence demonstrates that MSDV is an avian adenovirus, the first recognized in the ring-necked pheasant (Phasianus colchicus L.). Images PMID:193796

  19. Surfactants at the Design Limit.

    PubMed

    Czajka, Adam; Hazell, Gavin; Eastoe, Julian

    2015-08-01

    This article analyzes how the individual structural elements of surfactant molecules affect surface properties, in particular, the point of reference defined by the limiting surface tension at the aqueous cmc, ?cmc. Particular emphasis is given to how the chemical nature and structure of the hydrophobic tails influence ?cmc. By comparing the three different classes of surfactants, fluorocarbon, silicone, and hydrocarbon, a generalized surface packing index is introduced which is independent of the chemical nature of the surfactants. This parameter ?cmc represents the volume fraction of surfactant chain fragments in a surface film at the aqueous cmc. It is shown that ?cmc is a useful index for understanding the limiting surface tension of surfactants and can be useful for designing new superefficient surfactants. PMID:25797065

  20. Surface characteristics of etched parylene-C films for low-damaged patterning process using inductively-coupled O2/CHF3 gas plasma

    NASA Astrophysics Data System (ADS)

    Ham, Yong-Hyun; Shutov, Dmitriy Alexandrovich; Kwon, Kwang-Ho

    2013-05-01

    We investigated the effectiveness of CHF3 admixture in O2 plasma for a low damage patterning process. We used inductively-coupled plasma (ICP) etching of parylene-C thin films with O2/CHF3 gas mixtures. Plasma diagnostics were performed by using a double Langmuir probe. Also in order to examine the relationship between the plasma and surface energy, we attempted to conduct a simplified model-based analysis of the CHF3/O2 plasma. The surface energy decreased as the admixture fraction increased with fluorocarbon containing gas. The decreased surface energy is related to the functional groups of CFx polymer at binding energy of around 290 eV and low ion physical damage. We observed that a small addition of CHF3 to O2 plasma produced a high etch rate, low surface energy, and low roughness compared to pure oxygen plasma.

  1. Elastohydrodynamic film thickness model for heavily loaded contacts

    NASA Technical Reports Server (NTRS)

    Loewenthal, S. H.; Parker, R. J.; Zaretsky, E. V.

    1973-01-01

    An empirical elastohydrodynamic (EHD) film thickness formula for predicting the minimum film thickness occurring within heavily loaded contacts (maximum Hertz stresses above 1.04 GN/sq m (150,000 psi)) was developed. The formula was based upon X-ray film thickness measurements made with synthetic paraffinic, fluorocarbon, Type II ester, and polyphenyl ether fluids covering a wide range of test conditions. Comparisons were made between predictions from an isothermal EHD theory and the test data. The deduced relationship was found to adequately reflect the high-load dependence exhibited by the measured data. The effects of contact geometry, material, and lubricant properties on the form of the empirical model are also discussed.

  2. Development of inspection techniques for quantitatively measuring surface contamination on SRM hardware

    NASA Technical Reports Server (NTRS)

    Law, R. D.

    1989-01-01

    A contaminant is any material or substance which is potentially undesirable or which may adversely affect any part, component, or assembly. Contamination control of SRM hardware surfaces is a serious concern, for both Thiokol and NASA, with particular concern for contaminants which may adversely affect bonding surfaces. The purpose of this study is to develop laboratory analytical techniques which will make it possible to certify the cleanliness of any designated surface, with special focus on particulates (dust, dirt, lint, etc.), oils (hydrocarbons, silicones, plasticizers, etc.), and greases (HD-2, fluorocarbon grease, etc.). The hardware surfaces of concern will include D6AC steel, aluminum alloys, anodized aluminum alloys, glass/phenolic, carbon/phenolic, NBR/asbestos-silica, and EPDM rubber.

  3. Nano-coatings on carbon structures for interfacial modification

    NASA Astrophysics Data System (ADS)

    Pulikollu, Rajasekhar V.

    Surface modification of materials is a rapidly growing field as structures become smaller, more integrated and complex. It opens up the possibility of combining the optimum bulk properties of a material with optimized surface properties such as enhanced bonding, corrosion resistance, reactivity, stress transfer, and thermal, optical or electrical behavior. Therefore, surface functionalization or modification can be an enabling step in a wide variety of modern applications. In this dissertation several surface modification approaches on carbon foam and carbon nano-fibers will be discussed. These are recently developed sp2 graphitic carbon based structures that have significant potential in aerospace, automotive and thermal applications. Influence of surface modification on composite formation and properties have also been investigated. Two types of property changes have been investigated: one for enhancing the surface reactivity and another for surface inertness. Characterization techniques such as X-ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM), Contact Angle Measurement, Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) and mechanical testing are used in this study to find out the influence of these coatings on surface composition, chemistry and morphology. Mechanical testing has been performed on composites and stand alone foam to study the influence of surface modification on physical and mechanical properties of the composite materials. The effectiveness of these coatings on metallic/graphite interface has also been investigated for metal-matrix composite related applications. Additionally, the influence of plasma coatings on nucleation and growth of nanotubes on larger carbon structures (to produce multiscale, multifunctional materials) have also been studied. It is seen that the liquid phase activation treatment introduces oxygen functional groups on the surface, but may cause severe enough degradation that damages the ligaments and cell walls of carbon foam. This results in higher elastic modulus but lower strength. So, to get any benefit from such approaches the optimization window may be very narrow and marginal in controllability. An alternative solution would be to synthesize ultra thin film coatings without etching the surfaces. It is observed that plasma assisted coatings having thickness in the range of few nanometers (4-5nm) are completely covering the graphite substrates. The coating surface chemistry and morphology information is based upon XPS and AFM studies on pyrolytic graphite substrate. Two types of plasma surface modification techniques have been attempted: one is to make the surface more reactive for structural components and the other is to make the surface more inert for stand-alone structures. In order to achieve these goals plasma assisted oxide and fluorocarbon coatings are studied in detail. The synthesized oxide and fluorocarbon coating chemistries are comparable to conventional silica (SiO2) and polytetrafluoroethylene (PTFE, -CF2-). It is seen that the fluorocarbon coatings provide moisture resistance to graphitic foam by making the surface inert at the nanometer scale. On the other hand, plasma assisted oxide coating is a feasible and effective means of improving the wettability and dispersion of foam and nanofibers in organic polymer matrix material. Surface analysis as well as microstructural studies and mechanical tests have shown encouraging results. The interface reactions between graphite (coated and uncoated) and epoxy have also been studied in detail. Nano-scale plasma coatings have also been applied for metal matrix composites and semiconductor related applications. The fluorocarbon coating promote delamination/exfoliation of the metal on graphite, hence may be used for patterning or lithography. Oxide coatings seem to enhance the adhesion and metallic diffusion between graphite and metal, hence can be used for the development of metal matrix composites. Additionally, oxide coating seems to enhance the length and density of nanotubes synthesized on carbon structures, desired for the design of advanced nano-composites.

  4. Chlorofluoromethanes in the stratosphere and some possible consequences for ozone

    NASA Technical Reports Server (NTRS)

    Turco, R. P.; Whitten, R. C.

    1975-01-01

    Inert chlorofluoromethanes are used by man as refrigerants and aerosol propellants. These substances eventually escape and diffuse upward into the stratosphere. At great enough heights, UV sunlight can photodissociate these chlorofluorocarbons into chlorine atoms which will catalytically destroy ozone molecules. Chlorofluoromethane production has been increasing steadily in recent years to its present level of about a megaton per year, and chlorofluorocarbon usage will probably continue to grow in the future. Calculations with a one-dimensional time-dependent atmospheric model suggests that, if projected increases in chlorofluoromethane use materialize and there is no tropospheric destruction mechanism for these gases, the total global abundance of ozone may be reduced by more than 20 per cent over the next 50 years. If the residence times for these fluorocarbons in the troposphere are in the range of 10-30 years, however, predicted ozone depletions would be significantly smaller.

  5. Krypton retention on solid adsorbents. [Activated alumina; hydrogen mordenite, silver mordenite, sodium mordenite, cerium mordenite-H, cerium mordenite-Na, potassium mordenite-H, potassium mordenite-Na

    SciTech Connect

    Monson, P.R. Jr.

    1982-01-01

    An experimental laboratory program was conducted to develop economical solid adsorbents for the retention of krypton from a dissolver off-gas stream. The study indicates that a solid adsorbent system is feasible and competitive with other developing systems which utilize fluorocarbon absorption nd cryogenic distillation. This technology may have potential applications not only in nuclear fuel reprocessing plants, but also in nuclear reactors and in environmental monitoring. Of the 13 prospective adsorbents evaluated with respect to adsorption capacity and cost, the commercially available hydrogen mordenite was the most cost-effective material at subambient temperatures (-40/sup 0/ to -80/sup 0/C). Silver mordenite has a higher capacity for krypton retention, but is 50 times more expensive than hydrogen mordenite.

  6. Energy Efficient Commercial Refrigeration with Carbon Dioxide Refrigerant and Scroll Expanders

    SciTech Connect

    Dieckmann, John

    2013-04-04

    Current supermarket refrigeration systems are built around conventional fluorocarbon refrigerants – HFC-134a and the HFC blends R-507 and R404A, which replaced the CFC refrigerants, R-12 and R-502, respectively, used prior to the Montreal Protocol phase out of ozone depleting substances. While the HFC refrigerants are non-ozone depleting, they are strong greenhouse gases, so there has been continued interest in replacing them, particularly in applications with above average refrigerant leakage. Large supermarket refrigeration systems have proven to be particularly difficult to maintain in a leak-tight condition. Refrigerant charge losses of 15% of total charge per year are the norm, making the global warming impact of refrigerant emissions comparable to that associated with the energy consumption of these systems.

  7. Extraction studies. Final report, May 6, 1996--September 30, 1997

    SciTech Connect

    1997-10-09

    During the first week of this effort, an Alpkem RFA-300 4-channel automated chemical analyzer was transferred to the basement of building 42 at TA-46 for the purpose of performing extraction studies. Initially, this instrumentation was applied to soil samples known to contain DNA. Using the SFA (Segmented Flow Analysis) technique, several fluidic systems were evaluated to perform on-line filtration of several varieties of soil obtained from Cheryl Kuske and Kaysie Banton (TA-43, Bldg. 1). Progress reports were issued monthly beginning May 15, 1996. Early in 1997 there was a shift from the conventional 2-phase system (aqueous + air) to a 3-phase system (oil + aqueous + air) to drastically reduce sample size and reagent consumption. Computer animation was recorded on videotape for presentations. The time remaining on the subcontract was devoted to setting up existing equipment to incorporate the 3rd phase (a special fluorocarbon oil obtained from DuPont).

  8. PFC Decontamination of a Metal Surface and the Recycling of a Spent PFC Solution

    SciTech Connect

    Jung, C.H.; Won, H.J.; Oh, W.Z.; Moon, J.K.; Park, J.H.

    2006-07-01

    PFC (per-fluorocarbon) ultrasonic decontamination behavior of loosely contaminated metal specimens such as a plate, pipe, welding and a crevice specimen in a mixed solution of PFC and an anionic surfactant was investigated. Perfluoroheptane (C{sub 7}F{sub 16}) was used as a PFC ultrasonic media. The contaminants were completely removed for almost all of the tested specimens except for the longest pipe length specimen. For the 6-cm long specimen, 98.5 % of the contaminants were removed. For the recycling of the PFC solution, a distillation test for the spent PFC solution was also performed. The results show that 97.5 % of the PFC was recycled without a loss of the decontamination efficiency. (authors)

  9. Nondestructive decontamination of radioactive electronic equipment by fluorinated surfactant solutions

    SciTech Connect

    Yam, C.S.; Harling, O.K.; Kaiser, R.

    1995-12-31

    The application of ESI`s enhanced particle removal process, initially developed for the cleaning of inertial guidance instrument parts, to the nondestructive decontamination of nuclear equipment is discussed. The cleaning medium used in this process is a solution of a high molecular weight fluorocarbon surfactant in an inert perfluorinated liquid which results in enhanced particle removal. The perfluorinated liquids of interest, which are recycled in the process, are non-toxic, nonflammable, generally safe to use, and do not present a hazard to the atmospheric ozone layer. An experimental cleaning system has been developed by ESI to demonstrate the application of this cleaning process to nuclear decontamination of electronic circuit boards. A high degree of decontamination is obtained and with no resulting physical damage to the circuits.

  10. A fluorinated detergent for membrane-protein applications.

    PubMed

    Frotscher, Erik; Danielczak, Bartholomus; Vargas, Carolyn; Meister, Annette; Durand, Grgory; Keller, Sandro

    2015-04-20

    Surfactants carrying fluorocarbon chains hold great promise as gentle alternatives to conventional hydrocarbon-based detergents for the solubilization and handling of integral membrane proteins. However, their inertness towards lipid bilayer membranes has limited the usefulness of fluorinated surfactants in situations where detergent-like activity is required. We demonstrate that fluorination does not necessarily preclude detergency, as exemplified by a fluorinated octyl maltoside derivative termed F6 OM. This nonionic compound readily interacts with and completely solubilizes phospholipid vesicles in a manner reminiscent of conventional detergents without, however, compromising membrane order at subsolubilizing concentrations. Owing to this mild and unusual mode of detergency, F6 OM outperforms a lipophobic fluorinated surfactant in chaperoning the functional refolding of an integral membrane enzyme by promoting bilayer insertion in the absence of micelles. PMID:25753129

  11. Investigation of structure-surface properties relationship of semi-fluorinated polymerizable cationic surfactants.

    PubMed

    Benbayer, Chahinez; Saidi-Besbes, Salima; Taffin de Givenchy, Elisabeth; Amigoni, Sonia; Guittard, Frdric; Derdour, Aicha

    2013-10-15

    Novel hybrid hydrocarbon/fluorocarbon ammonium type surfactant monomers (surfmers) of the general formula RF (CH2)l N(CH3)2(CH2)mOCOCH=CH2 with (RF=C4F9, C6F13, C8F17, l=4, 6, 11, and m=2-11) were synthesized and characterized. They exhibit very low surface tension as well as low critical micellar concentrations down to 1.3910(-5)mol/L. Special attention was focused on theeffect of the polymerizable moiety, the length of the hydrocarbon spacers, and the fluorinated chains on surface activities of the reactive surfactants as compared to hydrocarbon surfmer analogs. Results indicate that the acrylic function has a pronounced effect on increasing the hydrophobic micelle character. This was confirmed by surface tensions and average surfaces occupied by these molecules at the water-gas interface. The micellar sizes were investigated by dynamic light scattering. PMID:23932087

  12. Ionic cleaning after wave solder and before conformal coat

    NASA Astrophysics Data System (ADS)

    Nguygen, Tochau N.; Sutherland, Thomas H.

    An account is given of efforts made by a military electronics manufacturer to upgrade product reliability in response to the printed writing board (PWB) ionic cleanliness requirements recently set out in MIL-P-28809 Rev. A. These requirements had to be met both after wave soldering, involving the immediate removal of ionically active RA flux, and immediately before conformal coating, in order to remove the less active RMA flux and bonding contaminants. Attention is given to the results of a test program which compared the effectiveness with which five different solvents and two (batch and conveyorized vapor degreasing) cleaning methods cleaned representative PWBs containing many components. Alcohol-containing fluorocarbon blends were adequate, but the most densely packed PWBs required a supplemental water rinse.

  13. Fluorine bonding enhances the energetics of protein-lipid binding in the gas phase.

    PubMed

    Liu, Lan; Jalili, Nobar; Baergen, Alyson; Ng, Simon; Bailey, Justin; Derda, Ratmir; Klassen, John S

    2014-05-01

    This paper reports on the first experimental study of the energies of noncovalent fluorine bonding in a protein-ligand complex in the absence of solvent. Arrhenius parameters were measured for the dissociation of gaseous deprotonated ions of complexes of bovine ?-lactoglobulin (Lg), a model lipid-binding protein, and four fluorinated analogs of stearic acid (SA), which contained (X =) 13, 15, 17, or 21 fluorine atoms. In all cases, the activation energies (E(a)) measured for the loss of neutral XF-SA from the (Lg + XF-SA)?? ions are larger than for SA. From the kinetic data, the average contribution of each?>?CF? group to E(a) was found to be ~1.1 kcal mol?, which is larger than the ~0.8 kcal mol? value reported for?>?CH? groups. Based on these results, it is proposed that fluorocarbonprotein interactions are inherently stronger (enthalpically) than the corresponding hydrocarbon interactions. PMID:24658801

  14. Cell separations and the demixing of aqueous two phase polymer solutions in microgravity

    NASA Technical Reports Server (NTRS)

    Brooks, Donald E.; Bamberger, Stephan; Harris, J. M.; Van Alstine, James M.

    1991-01-01

    Partition in phase separated aqueous polymer solutions is a cell separation procedure thought to be adversely influenced by gravity. In preparation for performing cell partitioning experiments in space, and to provide general information concerning the demixing of immiscible liquids in low gravity, a series of phase separated aqueous polymer solutions have been flown on two shuttle flights. Fluorocarbon oil and water emulsions were also flown on the second flight. The aqueous polymer emulsions, which in one g demix largely by sedimentation and convection due to the density differences between the phases, demixed more slowly than on the ground and the final disposition of the phases was determined by the wetting of the container wall by the phases. The demixing behavior and kinetics were influenced by the phase volume ratio, physical properties of the systems and chamber wall interaction. The average domain size increased linearly with time as the systems demixed.

  15. An e.s.c.a. study of atomic oxygen interactions with phosphazene-coated polyimide films

    NASA Technical Reports Server (NTRS)

    Fewell, Larry L.; Finney, Lorie

    1991-01-01

    Metallic as well as most nonmetallic materials experience oxidation and mass loss via surface erosion in low earth orbit as shown in previous Space Shuttle flights. This study is an evaluation of select polyphosphazene polymers and their resistance to atomic oxygen attack. Electron spectroscopy for chemical analysis examinations of the surfaces of polyphosphazene coatings were monitored for microstructural changes induced during exposures to atomic oxygen. Sample exposures in oxygen plasmas and O(3P) beam were compared as to their effect on surface compositional changes in the polyphosphazene coating. High resolution line scans revealed rearrangements in the polymer backbone and scissioning reactions involving fluorocarbon units of long chain fluoroalkoxy pendant groups. Atom percents and peak areas of all species provided a detailed profile of the microstructural changes induced in phosphazene polymers as a result of exposures to atomic oxygen.

  16. Glazings 101

    SciTech Connect

    Kensil, D.

    1980-09-01

    A brief introduction to the solar industry is given with an analogy to the auto industry. Desired characteristics of glazing are listed and comparisons are made between glass and plastic glazing. The characteristics of each type of plastic used in glazing are discussed in the light of application for solar direct gain. Comparisons of glazing material are presented in a chart which includes: (1) glass; (2) acrylic; (3) polycarbonate; (4) fiber reinforced polyester; (5) laminate (acrylic polyester); (6) polyethylene; (7) polyester; (8) fluorocarbons; and (9) silicone treated cloth. For each general type of glazing, the trade names, comments, thickness, solar transmittance, infrared transmittance, maximum operating temperature, estimated lifetime, cost/ft/sup 2/, transparent or translucent, and lbs/ft/sup 2/ are given. Advantages and disadvantages are given for each product. 4 references. (MJJ)

  17. Corrosion of current-collector materials in Li-ion cells

    SciTech Connect

    Braithwaite, J.; Nagasubramanian, G.; Gonzales, A.; Lucero, S.; Cieslak, W.

    1996-12-01

    The primary current-collector materials being used in lithium-ion cells are susceptible to environmental degradation: aluminum to pitting corrosion and copper to environmentally assisted cracking. Pitting occurs at the highly oxidizing potentials associated with the positive-electrode charge condition. However, the pitting mechanism is more complex than that typically observed in aqueous systems in that the pits are filled with a mixed metal/oxide product and exist as mounds or nodules on the surface. Electrochemical impedance was shown to be an effective analytical tool for quantification and verification of visual observations and trends. Two fluorocarbon-based coatings were shown to improve the resistance of Al to localized pitting. Finally, environmental cracking of copper can occur at or near the lithium potential and only if specific metallurgical conditions exist (work hardening and large grain size).

  18. High DNA-Binding Affinity and Gene-Transfection Efficacy of Bioreducible Cationic Nanomicelles with a Fluorinated Core.

    PubMed

    Wang, Long-Hai; Wu, De-Cheng; Xu, Hang-Xun; You, Ye-Zi

    2016-01-11

    During the last two decades, cationic polymers have become one of the most promising synthetic vectors for gene transfection. However, the weak interactions formed between DNA and cationic polymers result in low transfection efficacy. Furthermore, the polyplexes formed between cationic polymers and DNA generally exhibit poor stability and toxicity because of the large excess of cationic polymer typically required for complete DNA condensation. Herein, we report the preparation of a novel class of bioreducible cationic nanomicelles by the use of disulfide bonds to connect the cationic shell to the fluorocarbon core. These bioreducible nanomicelles form strong interactions with DNA and completely condense DNA at an N/P ratio of 1. The resulting nanomicelle/DNA polyplexes exhibited high biocompatibility and performed very effectively as a gene-delivery system. PMID:26586102

  19. Drop size measurement of liquid aerosols

    NASA Astrophysics Data System (ADS)

    Liu, B. Y. H.; Pui, D. Y. H.; Xian-Qing, Wang

    The factor B = D/ D' relating the diameter D of a spherical liquid drop to the diameter, D, of the same drop collected on a microscope slide has been measured for DOP (di-octyl phthalate) and oleic acid aerosols. The microscope slide was coated with a fluorocarbon, oleophobic surfactant (L-1428, 3M Co., St. Paul, MN). The ratio was found to be independent of drop diameter in the 2-50 ?m range and the mean value of B was found to be 0.700 for oleic acid and 0.690 for DOP. Similar measurements for oleic acid and DOP drops collected on a clean, uncoated slide resulted in the values of 0.419 and 0.303, respectively. The experimental values of B were compared with the theoretical values based on contact angle measurements. Good agreement was obtained.

  20. Transparent superhydrophobic and highly oleophobic coatings.

    PubMed

    Cao, Liangliang; Gao, Di

    2010-01-01

    We report a facile process for fabrication of transparent superhydrophobic and highly oleophobic surfaces through assembly of silica nanoparticles and sacrificial polystyrene nanoparticles. The silica and polystyrene nanoparticles are first deposited by a layer-by-layer assembly technique. The polystyrene nanoparticles are then removed by calcination, which leaves a porous network of silica nanoparticles. The cavities created by the sacrificial polystyrene particles form overhang structures on the surfaces. Modified with a fluorocarbon molecule, such surfaces are superhydrophobic and transparent. They also repel liquids with low surface tensions, such as hexadecane, due to the overhang structures that prevent liquids from getting into the air pockets even though the intrinsic contact angles of these liquids are less than 90 degrees. PMID:21043414

  1. Development of Compact C2F4 Gas Supply Equipment and Its Application to Etching of Dielectrics in an Environmental Benign Process

    NASA Astrophysics Data System (ADS)

    Takahashi, Shunji; Den, Shoji; Katagiri, Toshirou; Yamakawa, Koji; Kano, Hiroyuki; Hori, Masaru

    2005-06-01

    Compact C2F4 gas supply equipment, which controls the gas supply with sufficient accuracy by irradiation of a carbon dioxide laser (CO2) onto a solid source (PTFE) without using any fluorocarbon gas, has been developed to combat global warming. Although C2F4 gas has a very low Global Warming Potential (GWP <1), it is very unstable and thus considerably difficult to handle. This gas is used in the semiconductor manufacture process, where it is obtained from a conventional high-pressure cylinder. By changing the output of the laser, the amount of C2F4 gas generated can be precisely controlled in this equipment while also ensuring safety. The gas is supplied to the VHF excited parallel plate plasma reactor through a gas shower head with Ar carrier gas and, in actual tests, this environmental benign technology achieved high etching performances for low-k SiOCH and SiO2 films.

  2. SAXS investigation on aggregation phenomena in supercritical \\chem{CO2}

    NASA Astrophysics Data System (ADS)

    Celso, F. Lo; Triolo, A.; Triolo, F.; Donato, D. I.; Steinhart, M.; Kriechbaum, M.; Amenitsch, H.; Triolo, R.

    2002-06-01

    Synchrotron Small-Angle X-Ray scattering (SAXS) measurements on aggregate formation of a Polyvinyl acetate-b-Perfluoro octyl acrylate (PVAc-b-PFOA) block copolymer in supercritical CO{2} are here reported. Experiments were carried out for a series of different thermodynamic conditions, changing the solvent density by profiling both the pressure at constant temperature and the temperature at constant pressure. This block copolymer and in general fluorocarbon-hydrocarbon di-blocks form aggregates depending on the value of CO{2} density. A sharp transition between monomers dissolved as random coils and micelles characterized by a solvophilic shell and a solvophobic core occurs when the CO{2} density reaches a critical value. Results of critical micellization density (CMD) derived from pressure and temperature ramps experiment along with the comparison with previous SANS results are here reported to give additional experimental support to the solvent density-driven aggregation process.

  3. Versatile Coating

    NASA Technical Reports Server (NTRS)

    1990-01-01

    A radome at Logan Airport and a large parabolic antenna at the Wang Building in Massachusetts are protected from weather, corrosion and ultraviolet radiation by a coating, specially designed for antennas and radomes, known as CRC Weathertite 6000. The CRC 6000 line that emerged from Boyd Coatings Research Co., Inc. is a solid dispersion of fluorocarbon polymer and polyurethane that yields a tough, durable film with superior ultraviolet resistance and the ability to repel water and ice over a long term. Additionally, it provides resistance to corrosion, abrasion, chemical attacks and impacts. Material can be used on a variety of substrates, such as fiberglass, wood, plastic and concrete in addition to steel and aluminum. In addition Boyd Coatings sees CRC 6000 applicability as an anti-icing system coated on the leading edge of aircraft wings.

  4. Aviation gas turbine lubricants - military and civil aspects: aviation fuel and lubricants - performance testing; Proceedings of the Aerospace Technology Conference and Exposition, Long Beach, CA, October 14-17, 1985

    SciTech Connect

    Not Available

    1985-01-01

    Research and development programs in the areas of gas turbine lubricants for civil and military aviation and the performance testing of aviation gas turbine fuels and lubricants are discussed. The topics addressed include: laboratory and field evaluation of a high temperature jet engine oil, performance advantages of high load aviation lubricants, fluorocarbon elastomer compatibility with gas turbine lubricants, potential benefits in the development of a dedicated helicopter transmission lubricant, and feasibility of formulating advanced four centistoke gas turbine oils. Also covered are: advanced lubricants for aircraft turbine engines, future trends for U.S. Naval aviation propulsion system lubricants, electrochemical evaluation of corrosivity in turbine engine oils, the influence of esters on elastomer seals, deposition in gas turbine oil systems, development of the portable water separometer for the WSIM test, influence of JFTOT operating parameters on the assessment of fuel thermal stability, and evaluation of JFTOT tube deposits by carbon burnoff.

  5. Pulsed Plasma Thruster Plume Study: Symmetry and Impact on Spacecraft Surfaces

    NASA Technical Reports Server (NTRS)

    Arrington, Lynn A.; Marrese, Colleen M.; Blandino, John J.

    2000-01-01

    Twenty-four witness plates were positioned on perpendicular arrays near a breadboard Pulsed Plasma Thruster (PPT) to collect plume constituents for analysis. Over one million shots were fired during the experiment at 43 J using fluorocarbon polymer propellant. The asymmetry of the film deposition on the witness plates was investigated with mass and thickness measurements and correlated with off-axis thrust vector measurements. The composition of the films was determined. The transmittance and reflectance of the films were measured and the absorption coefficients were calculated in the wavelength range from 350 to 1200 mn. These data were applied to calculate the loss in signal intensity through the films, which will impact the visibility of spaceborne interferometer systems positioned by these thrusters.

  6. Ultrasmooth plasma polymerized coatings for laser-fusion targets

    SciTech Connect

    Letts, S.A.; Myers, D.W.; Witt, L.A.

    1980-08-26

    Coatings for laser fusion targets were deposited up to 135 ..mu..m thick by plasma polymerization onto 140 ..mu..m diameter DT filled glass microspheres. Ultrasmooth surfaces (no defect higher than 0.1 ..mu..m) were achieved by eliminating particulate contamination. Process generated particles were eliminated by determining the optimum operating conditions of power, gas flow, and pressure, and maintaining these conditions through feedback control. From a study of coating defects grown over known surface irregularities, a quantitative relationship between irregularity size, film thickness, and defect size was determined. This relationship was used to set standards for the maximum microshell surface irregularity tolerable in the production of hydrocarbon or fluorocarbon coated laser fusion targets.

  7. Laboratory Studies of Chemical and Photochemical Processes Relevant to Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Zahniser, Mark S.; Nelson, David D.; Worsnop, Douglas R.; Kolb, Charles E.

    1996-01-01

    The purpose of this project is to reduce the uncertainty in several key gas-phase kinetic processes which impact our understanding of stratospheric ozone. The main emphasis of this work is on measuring rate coefficients and product channels for reactions of HOx and NOx species in the temperature range 200 K to 240 K relevant to the lower stratosphere. Other areas of study have included infrared spectroscopic studies of the HO radical, measurements of OH radical reactions with alternative fluorocarbons, and determination of the vapor pressures of nitric acid hydrates under stratospheric conditions. The results of these studies will improve models of stratospheric ozone chemistry and predictions of perturbations due to human influences.

  8. Manufacture and quality control of interconnecting wire hardnesses, Volume 1

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A standard is presented for manufacture, installation, and quality control of eight types of interconnecting wire harnesses. The processes, process controls, and inspection and test requirements reflected are based on acknowledgment of harness design requirements, acknowledgment of harness installation requirements, identification of the various parts, materials, etc., utilized in harness manufacture, and formulation of a typical manufacturing flow diagram for identification of each manufacturing and quality control process, operation, inspection, and test. The document covers interconnecting wire harnesses defined in the design standard, including type 1, enclosed in fluorocarbon elastomer convolute, tubing; type 2, enclosed in TFE convolute tubing lines with fiberglass braid; type 3, enclosed in TFE convolute tubing; and type 5, combination of types 3 and 4. Knowledge gained through experience on the Saturn 5 program coupled with recent advances in techniques, materials, and processes was incorporated.

  9. Novel direct vision prism and Wollaston prism assembly for diffraction limit applications

    NASA Astrophysics Data System (ADS)

    Ebizuka, Noboru; Yokota, Hideo; Kajino, Fumiyoshi; Kawabata, Koji S.; Iye, Masanori; Sato, Shuji

    2008-07-01

    We propose two types of novel prisms; 1) a direct vision prism with approximately linear angular dispersion as a function of wavelength (Liner dispersion prism: LDP) suitable for a wide range spectrometer, and 2) a novel Wollaston prism assembly (WPA) suitable for a polarizing imager and spectro-polarimeter with a wide wavelength coverage. LDP composes several kinds of glasses or plastics or crystals. Angular dispersion of LDP is enlarged by employment of with some kind of plastic. LDPs, which are employed polycarbonate and Cytop (Amorphous fluorocarbon resin), provide approximately linear angular dispersion in ultraviolet and visible wavelength, respectively. WPA is composed of two or three kinds of Wollaston prism with different birefringent crystals. WPA provides an achromatic angular separation or an angular separation with linear dispersion. These prisms will enable us to achieve a diffraction-limited capability on next generation telescopes of both ground-based and space-borne.

  10. Effects of tacky mat contamination on bond degradation for Chemlok/liner and NBR/liner bonds

    NASA Technical Reports Server (NTRS)

    Padilla, A. M.

    1989-01-01

    Tacky mats are placed by the rubber lay-up areas for the solid rocket motor segments. These mats dust off the shoes prior to entering the platform where the lay-up work is performed. The possibility exists that a tacky mat could be touched with gloved hands prior to handling the uncured nitride butadiene rubber (NBR). Tests were run to determine if NBR were accidentally touched would there be any degradation of the liner/NBR bond. The tacky mats were judged solely on the basis of bond degradation caused by either direct or indirect contamination. Test results all indicate that there was no notable NBR/Chemlok or liner/NBR bond degradation on samples that came into contact with the tacky mat material. Testing procedures are described. The tacky mat adhesive composition does not contain fluorocarbons or release agents that would affect bonding.

  11. Neutron Radiography of Fluid Flow for Geothermal Energy Research

    NASA Astrophysics Data System (ADS)

    Bingham, P.; Polsky, Y.; Anovitz, L.; Carmichael, J.; Bilheux, H.; Jacobsen, D.; Hussey, D.

    Enhanced geothermal systems seek to expand the potential for geothermal energy by engineering heat exchange systems within the earth. A neutron radiography imaging method has been developed for the study of fluid flow through rock under environmental conditions found in enhanced geothermal energy systems. For this method, a pressure vessel suitable for neutron radiography was designed and fabricated, modifications to imaging instrument setups were tested, multiple contrast agents were tested, and algorithms developed for tracking of flow. The method has shown success for tracking of single phase flow through a manufactured crack in a 3.81 cm (1.5 inch) diameter core within a pressure vessel capable of confinement up to 69 MPa (10,000 psi) using a particle tracking approach with bubbles of fluorocarbon-based fluid as the "particles" and imaging with 10 ms exposures.

  12. Nanoscale coatings for control of interfacial bonds and nanotube growth

    NASA Astrophysics Data System (ADS)

    Pulikollu, Rajasekhar V.; Mukhopadhyay, Sharmila M.

    2007-06-01

    This paper describes the usefulness of nanoscale coatings in improving some engineering materials having porous and uneven surfaces (microcellular foam, nanofibers, nanotubes, etc.). It is shown that 3-5 nm coatings deposited in microwave plasma can influence crucial properties for a wide variety of applications. Two coatings resulting in opposite chemistries have been studied, an oxide layer that increases surface reactivity , and a similar fluorocarbon layer that makes it inert. In-depth atomic level microscopic and spectroscopic investigations of nucleation and growth of these layers on various substrates have been reported earlier. The effectiveness of such coatings in modifying bond strength, wettability and catalytic activity of various porous and uneven carbon surfaces have been shown here. The following influences of nanoscale functional coatings have been elaborated upon: (a) modification of carbon-polymer interfaces (b) controlled metallization of carbon (c) influence of nano-coatings on catalytic activity, for formation of carbon nanotubes on larger structures.

  13. The PICASSO Dark Matter Experiment

    NASA Astrophysics Data System (ADS)

    Wichoski, Ubi

    2011-12-01

    The PICASSO experiment searches for cold dark matter through the direct detection of weakly interacting massive particles (WIMPs) via their spin-dependent interactions with fluorine at SNOLAB, SudburyON, Canada since 2002. The detection principle is based on the superheated droplet technique; the detectors consist of a gel matrix with millions of liquid droplets of superheated fluorocarbon (C4F10) dispersed in it. Recently, a new setup has been built and installed in the Ladder Lab area at SNOLAB. In the present phase of the experiment the Collaboration is running 4.5-litre detector modules with approximately 85 g of active mass per module. Here, we give an overview of the experiment and discuss the progress in background mitigation, in particular background discrimination in the PICASSO detectors.

  14. Status of the Picasso Experiment

    NASA Astrophysics Data System (ADS)

    Wichoski, Ubi

    2012-08-01

    The PICASSO experiment searches for cold dark matter through the direct detection of weakly interacting massive particles (WIMPs) via their spin-dependent interactions with fluorine at SNOLAB, Sudbury - ON, Canada. The detection principle is based on the superheated droplet technique; the detectors consist of a gel matrix with millions of liquid droplets of superheated fluorocarbon (C4F10) dispersed in it. The experiment has been taking data using 4.5-litre detector modules with approximately 80g of active mass per module. In this talk we will give an overview of the experiment, discuss the progress on the understanding of the superheated droplet technique and report on recent developments and future plans.

  15. Development of a special purpose spacecraft interior coating, phase 1

    NASA Technical Reports Server (NTRS)

    Bartoszek, E. J.; Nannelli, P.

    1975-01-01

    Coating formulations were developed consisting of latex blends of fluorocarbon polymers, acrylic resins, stabilizers, modifiers, other additives, and a variety of inorganic pigments. Suitable latex primers were also developed from an acrylic latex base. The formulations dried to touch in about one hour and were fully dry in about twenty-four hours under normal room temperature and humidity conditions. The resulting coatings displayed good optical and mechanical properties, including excellent bonding to (pre-treated) substrates. In addition, the preferred compositions were found to be self-extinguishing when applied to nonflammable substrates and could meet the offgassing requirements specified by NASA for the intended application. Improvements are needed in abrasion resistance and hardness.

  16. Metallic and nonmetallic coatings for ICF targets

    SciTech Connect

    Hendricks, C.D.; Crane, J.K.; Hsieh, E.J.; Meyer, S.F.

    1981-04-17

    Some fusion targets designed to be driven by 0.35 to 1 ..mu..m laser light are glass spheres coated with layers of various materials such as hydrocarbons, fluorocarbons, beryllium, copper, gold, platinum, etc. The glass shell, which is filled with gas, liquid or solid deuterium-tritium fuel, must have remarkably good surface and wall thickness uniformity. Methods for depositing the various materials will be discussed. They include plasma polymerization, electro-deposition, sputtering and evaporation. Many of the difficulties encountered in the coating processes are the result of coating on free spheres with very small radii - 35 to 500 micrometers. Several means of overcoming the problems will be described and experimental results presented.

  17. Acute inhalation toxicity evaluation of a 93:7 mixture of perfluoro-2-butene and 1-bromopropane, a replacement candidate for ozone depleting substances. Interim report, July--August 1997

    SciTech Connect

    Feldmann, M.L.; Leahy, H.F.; Vinegar, A.

    1997-10-01

    The DoD requires the development of toxicity profiles for chemical substitute candidates proposed to replace ozone depleting substances such as chloro- and fluorocarbons and halons. A 93:7 mixture of perfluoro-2-butene and 1-bromopropane was identified as a possible replacement candidate for ozone-depleting fire extinguishants. An acute inhalation toxicity test utilizing male and female Fischer 344 rats was performed on this test material. No deaths occurred in any of the rats exposed to 5.3 mg/L of the 93:7 perfluoro-2-butene and 1-bromopropane mixture. Body weights of male and female rats during the subsequent 14-day observation period were unaffected by treatment. The test material did not produce acute toxicity via the inhalation route.

  18. Alternative training agents, phase 1. Survey of near-term candidate fire extinguishing agents and predicting properties of halocarbon mixtures, volume 1

    NASA Astrophysics Data System (ADS)

    Nimitz, Jonathan S.; Tapscott, Robert E.; Skaggs, Stephanie R.; Beeson, Harold D.

    1991-02-01

    In this report, 14 compounds are examined as potential near-term candidates for alternative firefighter training agents for streaming applications. This list consists of suitable fluorine-containing compounds (primarily fluorocarbons, hydrofluorocarbons, and hydrochlorofluorocarbons) known to have had significant toxicity testing completed, with bulk production capabilities existing in the past, present, or anticipated near future. Many of these compounds are being produced or considered as replacements for chlorofluorocarbons (CFCs) in refrigeration and foam-blowing applications. The ozone depletion potential, global warming potential, stage of toxicity testing, toxicity, availability, and relative cost of each compound are discussed. Physical and thermodynamic properties and estimated and measured flame suppression concentrations are reported. Those compounds that have low toxicity (with significant testing completed) are available in bulk and have desirable properties are discussed in detail. It is recommended that HCFC-123 be tested both in pure form and in blends as potential replacement training agents. Twelve blends are recommended for fire suppression.

  19. Avoiding Steric Congestion in Dendrimer Growth through Proportionate Branching. A Twist on da Vinci's Rule of Tree Branching

    SciTech Connect

    Yue, Xuyi; Taraban, Marc B.; Hyland, Laura L.; Yu, Yihua Bruce

    2012-10-05

    In making defect-free macromolecules, the challenge occurs during chemical synthesis. This challenge is especially pronounced in dendrimer synthesis where exponential growth quickly leads to steric congestion. To overcome this difficulty, proportionate branching in dendrimer growth is proposed. In proportionate branching, both the number and the length of branches increase exponentially but in opposite directions to mimic tree growth. The effectiveness of this strategy is demonstrated through the synthesis of a fluorocarbon dendron containing 243 chemically identical fluorine atoms with a MW of 9082 Da. Monodispersity is confirmed by nuclear magnetic resonance spectroscopy, mass spectrometry, and small-angle X-ray scattering. Moreover, growing different parts proportionately, as nature does, could be a general strategy to achieve defect-free synthesis of macromolecules.

  20. The Effect of Oil Contamination on Evaporator Heat Transfer Characteristics of CO2 Refrigeration Cycle

    NASA Astrophysics Data System (ADS)

    Katsuta, Masafumi; Kinpara, Hiromitsu; Yagi, Shunta; Mukaiyama, Hiroshi

    Because of the destructions of ozone layers and global warming, it is urgently necessary to abolish fluorocarbon refrigerants of HFCs and substitute them with natural refrigerants. Among several choices of natural refrigerants, CO2, which has an excellent thermal property, has the advantage for practical application. However, heat transfer coefficient and pressure drop of evaporator have not studied enough. No available correlation has been established. The refrigerant of CO2 is extremely sensitive to oil. Therefore, the research on the refrigerant under the circumstances that it is mixed with oil is very limited. It is the purpose of this research to examine the oil mixing effects on thermal and fluid dynamic behaviors and establish correlation.

  1. Thermodynamic and transport properties of some alternative ozone-safe refrigerants for industrial refrigeration equipment: Study in Belarus and Ukraine

    NASA Astrophysics Data System (ADS)

    Grebenkov, A. J.; Zhelezny, V. P.; Klepatsky, P. M.; Beljajeva, O. V.; Chernjak, Yu. A.; Kotelevsky, Yu. G.; Timofejev, B. D.

    1996-05-01

    The study of several hydrofluorocarbons (HFC) and fluorocarbons (FC) and their binary mixtures that have no ozone-depleting ability is being carried Out in the framework of Belarus National Program. The fluids include HFCs R134a. R152a, R135, and R32, and FC R218. The following properties are being investigated: ( I ) phase equilibrium parameters including the boiling and condensing curve and critical point, thermophysical properties at these parameters, and heat of evaporation: (2) isobaric and isochoric heat capacity, ethalpy, and entropy in the gas and liquid state: (3) speed of sound, thermal conductivity. viscosity, and density in the gas and liquid state: (4) dielectric properties and surface tension: (5) behavior of combined construction materials inside the refrigerant medium: and (6) solubility in compressor oils and other technological characteristics. The series of results obtained by authors during the period 1990 1993 is presented.

  2. Tetraperchlorate of methane

    NASA Technical Reports Server (NTRS)

    Schack, C. J.

    1972-01-01

    The preparation of the tetraperchlorate of methane (TPM) was attempted. Displacement of halogen from carbon tetrahalides was accomplished with either CCl4 or CBr4 using the halogen perchlorates, ClOClO3, and BOClO3. Although the displacement process was successful, the generated carbon perchlorate intermediates were not isolated. Instead, these species decomposed to COCl2, CO2, and Cl2O7. The vigorous displacement reaction that often occurred required moderation. Fluorocarbon solvents and chlorine perchlorate were successfully tested for compatibility, permitting their use in these synthetic reactions. While the sought for moderating effect was obtained, the net result of the displacement of halogen from CX sub 4 substrates was the same as before. Thus only CO2, COCl2, and Cl2O7 were isolated.

  3. The importance of the Montreal Protocol in protecting climate.

    PubMed

    Velders, Guus J M; Andersen, Stephen O; Daniel, John S; Fahey, David W; McFarland, Mack

    2007-03-20

    The 1987 Montreal Protocol on Substances that Deplete the Ozone Layer is a landmark agreement that has successfully reduced the global production, consumption, and emissions of ozone-depleting substances (ODSs). ODSs are also greenhouse gases that contribute to the radiative forcing of climate change. Using historical ODSs emissions and scenarios of potential emissions, we show that the ODS contribution to radiative forcing most likely would have been much larger if the ODS link to stratospheric ozone depletion had not been recognized in 1974 and followed by a series of regulations. The climate protection already achieved by the Montreal Protocol alone is far larger than the reduction target of the first commitment period of the Kyoto Protocol. Additional climate benefits that are significant compared with the Kyoto Protocol reduction target could be achieved by actions under the Montreal Protocol, by managing the emissions of substitute fluorocarbon gases and/or implementing alternative gases with lower global warming potentials. PMID:17360370

  4. Effect of double quaternary ammonium groups on micelle formation of partially fluorinated surfactant.

    PubMed

    Matsuoka, Keisuke; Chiba, Nagisa; Yoshimura, Tomokazu; Takeuchi, Emi

    2011-04-15

    To investigate the effect of divalency on the micelle properties, we synthesized divalent cationic surfactants composed of fluorocarbons and double quaternary ammonium groups N,N-dimethyl-N-[2-(N'-trimethylammonium)ethyl]-1-(3-perfluoroalkyl-2-hydroxypropyl) ammonium bromide [C(n)(F)C(3)-2Am; where n (=8 or 10) represents the number of carbon atoms in the fluorocarbon chain]. The double quaternary ammonium groups are continuously combined by the ethylene spacer in the surfactant head group, which clearly distinguishes the molecular design of the surfactant from those of the other typical divalent surfactants, bolaform and gemini types. The presence of the divalent head group results in an advantageous increase in their solubility [i.e., rise in the critical micelle concentration (cmc)]; however, the extra electrostatic repulsion between divalent cations decreases the surface activity in comparison with monovalent homologous fluorinated surfactants. The cmc, surface tension at cmc, and area occupied by a surfactant molecule in aqueous solution at 298.2K are 4.32 mM, 30.6 mN m(-1), and 0.648 nm(2 )molecule(-1), respectively, for C(8)(F)C(3)-2Am, and 1.51 mM, 30.4 mN m(-1), and 0.817 nm(2) molecule(-1), respectively, for C(10)(F)C(3)-2Am. The micellar size and shape were investigated by dynamic light scattering and freeze-fracture transmission electron microscopy (TEM). The TEM micrographs show that C(n)(F)C(3)-2Am (n=8 and 10) mainly forms ellipsoidal micelles approximately 10-100 nm in size for n=8 and approximately 10-20 nm in size for n=10. The degree of counterion binding to micelle was determined by selective electrode potential measurements, and the results of 0.7-0.8 agree with the average values for conventional monovalent ionic surfactants. PMID:21300366

  5. Adsorption of gemini surfactants with partially fluorinated chains at three different surfaces: neutron reflectometry results.

    PubMed

    Li, Pei Xun; Dong, Chu Chuan; Thomas, Robert K; Wang, Yi Lin

    2011-01-18

    The adsorption of six symmetrical cationic (dimethylammonium bromide) gemini surfactants with four different partially fluorinated chains at three different surfaces--the air/water, the hydrophilic silica/water, and the hydrophobic (octadecyltricholorosilane (OTS))/water--has been investigated by neutron reflectometry. The corresponding single chain trimethylammonium bromides have also been studied at the two solid surfaces. Four of the geminis with a C(6) spacer and chains with differing amounts of fluorocarbon have identical limiting areas per molecule at the air/water interface (106 5 (2)). This is similar to the value for the corresponding hydrocarbon gemini with a C(6) spacer and C(12) side chains, but unlike the hydrocarbon gemini, it is significantly more than twice the area per molecule of the corresponding single chain cationic. In adsorbed aggregates on hydrophilic silica the area per molecule decreases from the air/water value by an average of about 25%, indicating a substantial improvement in the packing of these geminis in the aggregate, which can be attributed to the stronger interaction between the hydrophobic chains in the interior of the aggregates. On the hydrophobic OTS surface the area per molecule in the adsorbed monolayer for three partially fluorinated geminis decreased by about 15% from the air/water value, again indicating much more favorable packing next to the hydrophobic OTS, but for one of the geminis, fC(8)C(6)-C(6)-C(6)fC(8), the change in area was reversed. This reversal is accompanied by a marked thinning of the layer, which is attributed to a shift in the balance between the interactions of the hydrocarbon spacer and fluorocarbon chain fragments and the OTS surface. PMID:21166453

  6. Protic ionic liquids with fluorous anions: physicochemical properties and self-assembly nanostructure.

    PubMed

    Shen, Yan; Kennedy, Danielle F; Greaves, Tamar L; Weerawardena, Asoka; Mulder, Roger J; Kirby, Nigel; Song, Gonghua; Drummond, Calum J

    2012-06-14

    A series of 11 new protic ionic liquids with fluorous anions (FPILs) have been identified and their self-assembled nanostructure, thermal phase transitions and physicochemical properties were investigated. To the best of our knowledge this is the first time that fluorocarbon domains have been reported in PILs. The FPILs were prepared from a range of hydrocarbon alkyl and heterocyclic amine cations in combination with the perfluorinated anions heptafluorobutyrate and pentadecafluorooctanoate. The nanostructure of the FPILs was established by using small- and wide-angle X-ray scattering (SAXS and WAXS). In the liquid state many of the FPILs showed an intermediate range order, or self-assembled nanostructure, resulting from segregation of the polar and nonpolar hydrocarbon and fluorocarbon domains of the ionic liquid. In addition, the physicochemical properties of the FPILs were determined including the melting point (T(m)), glass transition (T(g)), devitrification temperature (T(c)), thermal stability and the density ?, viscosity ?, air/liquid surface tension ?(LV), refractive index n(D), and ionic conductivity ?. The FPILs were mostly solids at room temperature, however two examples 2-pyrrolidinonium heptafluorobutyrate (PyrroBF) and pyrrolidinium heptafluorobutyrate (PyrrBF) were liquids at room temperature and all of the FPILs melted below 80 C. Four of the FPILs exhibited a glass transition. The two liquids at room temperature, PyrroBF and PyrrBF, had a similar density, surface tension and refractive index but their viscosity and ionic conductivity were very different due to dissimilar self-assembled nanostructure. PMID:22569799

  7. Patterns of trace gases near sources of global pollution

    SciTech Connect

    Khalil, M.A.K.; Rasmussen, R.A. )

    1990-08-01

    Many trace gases are increasing in the earth's armosphere and may couase global environmental changes in the future. Consequently there has been growing interest in the cycles of the long-lived gases that are likely to contribute the most to global change. At present there are four such gases: methane (CH{sub 4}), nitrous oxide (N{sub 2}0), trichlorofluoromethane (CCl{sub 3}F,F-11), and dichlorodifluoromethane (CCl{sub 2}F{sub 2},F-12). Methane and N{sub 2}O are involved mostly in adding to the greenhouse effect with some role in the stratospheric ozone cycle, and the two main fluorocarbons (F-11 and F-12) are involved in the depletion of the ozone layer with some role in global warming. This paper is about the patterns of these trace gases near regions of global scale pollution. Our purpose is to provide a synthesis of observations from diverse environments and ecosystems of the world and to provide readers with intuitive connections between sources and concentrations. We will consider four types of regions: rice fields in CHina that are a major source of methane, urban areas of the United States and China that are sources of fluorocarbons and other gases, rivers and surrounding wetlands, specifically the Yangtze in China and the Amazon in Brazil, and finally the environment of Boola Boola National Forest in Australia populated by many speices of termites that are a source of methane to the atmosphere. Eventually these patterns can be translated into estimeates of fluxes from the various sources of global pollution.

  8. Damage by radicals and photons during plasma cleaning of porous low-k SiOCH. I. Ar/O{sub 2} and He/H{sub 2} plasmas

    SciTech Connect

    Shoeb, Juline; Wang Mingmei; Kushner, Mark J.

    2012-07-15

    Porous dielectric materials offer lower capacitances that reduce RC time delays in integrated circuits. Typical porous low dielectric (low-k) materials include SiOCH-silicon dioxide with carbon groups, principally -CH{sub 3}, lining the pores. Fluorocarbon plasmas are often used to etch such low-k materials. These processes leave a fluorocarbon polymer on the SiOCH surface that must be removed, often with oxygen or hydrogen containing plasmas. Pores open to the surface and that are internally connected provide pathways for reactive species to enter into the porous network and produce damage. For example, during cleaning using O{sub 2} containing plasmas, reactions of O atoms with -CH{sub 3} groups can increase the k-value by removing C atoms. Vacuum ultraviolet (VUV) photons produced by the plasma and that penetrate into the material can scission -Si-CH{sub 3} bonds and accelerate the removal of -CH{sub 3} groups. This paper reports on results from a computational investigation of Ar/O{sub 2} and He/H{sub 2} plasma cleaning of porous SiOCH when including the effects of VUV photons. The authors found that He/H{sub 2} plasmas are able to clean CF{sub x} polymers deposited during etching while producing milder damage to underlying -CH{sub 3} sites compared to O{sub 2} plasmas due to the lower reactivity of H atoms and the shorter penetration distance of photons produced in He/H{sub 2} plasmas.

  9. Polarized infrared study on the structure of two-dimensional nanoclusters of partially fluorinated long-chain fatty acid salts at ambient and elevated temperatures

    NASA Astrophysics Data System (ADS)

    Ren, Yanzhi; Iimura, Ken-ichi; Kato, Teiji

    2000-07-01

    Atomic force microscopy (AFM) images of the single monolayer of five partially fluorinated fatty acid salts [CF3(CF2)m(CH2)nCOO-]2Cd2+ [(m,n)=(7,10), (7,16), (7,22), (5,22), and (3,22)] transferred from aqueous Cd2+ subphase to solid substrate revealed that the molecules had assembled into monodispersed two-dimensional clusters of tens of nanometers, whose morphology developed systematically with (m,n). Polarized infrared measurements detected a corresponding change with (m,n) in the -(CF2)-m and -(CH2)-n orientation angles. It is found that the van der Waals interaction between the C-C-C trans zig-zag planes of adjacent hydrocarbon segments is the driving force for the cluster formation, while the overlapping interaction between the fluorocarbon tails of neighbor salt molecules is responsible for cluster compactness. Grazing incidence reflection absorption spectra of the (m,n)=(7,10) single monolayer recorded during temperature elevation from 25 to 150 C show that heating has caused the hydrocarbon chain and the terminal C-CF3 axis to be gradually randomly oriented, while the carboxylate C2 symmetry axis and the fluorocarbon long axis to realign toward the substrate normal. It is discovered that the single monolayer has thermal memory and cyclic heating-cooling treatment can render an excellent thermal stability of 120 C to the -(CH2)-10 and CF3(CF2)-7 orientations. The different thermal behavior of the corresponding five-layer Y-type LB films, reported by Naselli, Swalen, and Rabolt [J. Chem. Phys. 90, 3855 (1989)] was explained as due to the longitudinal interaction between the headgroups of adjacent layers.

  10. TEWI Analysis: Its Utility, Its Shortcomings, and Its Results

    SciTech Connect

    Baxter, V.D.; Fischer, S.K.; Sand, J.R.

    1999-09-13

    The past decade has been a challenging time for the refrigeration and air conditioning industry worldwide. Provisions of the Montreal Protocol and its amendments require the phaseout of chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) compounds that have been used extensively as insulating foam blowing agents and refrigerants in refrigeration systems, heat pumps, and air conditioners. In response, hydrofluorocarbon (HFC) compounds were proposed, developed, and are starting to be used as the primary alternatives to CFCs and HCFCs. However, in 1997 under the Kyoto Protocol, industrialized nations have agreed to roll back emissions of HCFCs, carbon dioxide (CO*), and four other greenhouse gases which threaten to cause excessive global warming. The US. Department of Energy and the Alternative Fluorocarbon Environmental Acceptability Study (AFEAS) jointly sponsored research projects to identify the major applications of CFCs, HCFCs, and HFCs and to examine the impacts of these compounds and the energy use of applications employing these compounds on global warming. The five major uses of fluorocarbons based on sales were automobile air conditioning, supermarket refrigeration, unitary heat pumps and air conditioning, chillers for cooling large office buildings, and household refrigeration. Almost all of the refrigerants used in these applications are global warming gases, and if the refrigerant leaks out of the system during operation, is lost during maintenance or is not recovered when the system is scraped, it contributes to global warming. But, it is also true that the energy consumed by refrigeration and air conditioning systems, in the form of electricity or the direct combustion of fossil fuel, results in the release of CO*, the primary cause of atmospheric global warming.

  11. Lyotropic liquid crystal phases of phytantriol in a protic ionic liquid with fluorous anion.

    PubMed

    Shen, Yan; Greaves, Tamar L; Kennedy, Danielle F; Weerawardena, Asoka; Kirby, Nigel; Song, Gonghua; Drummond, Calum J

    2014-10-21

    The phase behaviour of phytantriol in the protic ionic liquid (PIL) 1-methylimidazolium pentadecafluorooctanoate (MImOF) and four different MImOF-water compositions was investigated by small- and wide-angle X-ray scattering (SAXS/WAXS), cross polarised optical microscopy (CPOM) and infrared spectroscopy (IR). MImOF is a distinct protic ionic liquid in that it contains a fluorocarbon anion and a hydrocarbon cation. This leads to MImOF having an unusual liquid nanostructure, such that it contains fluorocarbon, hydrocarbon and polar domains. No lyotropic liquid crystal phases were observed for phytantriol in neat MImOF. However, on addition of water, lamellar, cubic Ia3d and micellar phases were observed for specific MImOF-phytantriol-water compositions at room temperature, and up to 60 C. The phase behaviour for phytantriol in the solvent mixture of 25 wt%-MImOF-75 wt%-water was the most similar to the phytantriol-water phase diagram. Only this MImOF-water composition supported the Ia3d cubic phase, which had a lattice parameter between 100-140 compared to 86-100 in deionised water, indicating significant swelling due to the MImOF. IR spectroscopy showed that a percentage of the water molecules were hydrogen bonded to the N-H of the MIm cation, and this water decreased the hydrogen bonding present between the cation and anion of the ionic liquid. This investigation furthers our understanding of the interaction of ionic liquids with solutes, and the important role that the different IL nanostructures can have on influencing these interactions. PMID:25177837

  12. Chemical selectivity in micellar electrokinetic chromatography. II. Rationalization of elution patterns in different surfactant systems.

    PubMed

    Yang, S; Bumgarner, J G; Khaledi, M G

    1996-07-12

    Retention behavior in micellar electrokinetic chromatography (MEKC) is investigated using linear solvation energy relationships (LSERs) for two pseudo-stationary phases, one consisting of cationic micelles of tetradecyltrimethylammonium bromide (C14TAB) and the other of an anionic triblock copolymer, poly(methyl methacrylate-ethyl acrylate-methacrylic acid) (Elvacite 2669). It was found that solutes' migration behaviors in these two MEKC systems are mainly influenced by their size (V/100) and hydrogen bonding acceptor (HBA) strength (beta). However, solutes' hydrogen bonding donor (HBD) strength (alpha) has minor effects on their migration in MEKC. The characteristics of these two systems were compared to three other previously reported anionic micellar systems of sodium dodecyl sulfate (SDS) (anionic hydrocarbon), sodium cholate (SC) (anionic bile salt) and lithium perfluorooctane sulfonate (LiPFOS) (anionic fluorocarbon). It was concluded that hydrogen bonding interactions play a major role in providing different chemical selectivity among these five MEKC systems. Both C14TAB micelles and the ionic polymer of Elvacite 2669 provide hydrogen bonding acceptor (HBA) sites for solutes, which is similar to SC micelles. In fact, C14TAB is the strongest HBA, while Elvacite 2669 has HBA strength similar to that of SC micelles. On the other hand, the fluorocarbon micelles of LiPFOS are the strongest hydrogen bond donor (HBD) micelles, followed by the weak HBD SDS micelles. In general, cavity formation has little or no effect on chemical selectivity among hydrocarbon surfactant MEKC systems (i.e., SDS, SC and C14TAB). Information obtained from the LSER analysis is used to rationalize the elution patterns in MEKC with different types of pseudo-stationary phases. PMID:8696506

  13. Role of Acentric Displacements on the Crystal Structure and Second-Harmonic Generating Properties of RbPbCO3F and CsPbCO3F

    PubMed Central

    2015-01-01

    Two lead fluorocarbonates, RbPbCO3F and CsPbCO3F, were synthesized and characterized. The materials were synthesized through solvothermal and conventional solid-state techniques. RbPbCO3F and CsPbCO3F were structurally characterized by single-crystal X-ray diffraction and exhibit three-dimensional (3D) crystal structures consisting of corner-shared PbO6F2 polyhedra. For RbPbCO3F, infrared and ultraviolet–visible spectroscopy and thermogravimetric and differential thermal analysis measurements were performed. RbPbCO3F is a new noncentrosymmetric material and crystallizes in the achiral and nonpolar space group P6̅m2 (crystal class 6̅m2). Powder second-harmonic generation (SHG) measurements on RbPbCO3F and CsPbCO3F using 1064 nm radiation revealed an SHG efficiency of approximately 250 and 300 × α-SiO2, respectively. Charge constants d33 of approximately 72 and 94 pm/V were obtained for RbPbCO3F and CsPbCO3F, respectively, through converse piezoelectric measurements. Electronic structure calculations indicate that the nonlinear optical response originates from the distorted PbO6F2 polyhedra, because of the even–odd parity mixing of the O 2p states with the nearly spherically symmetric 6s electrons of Pb2+. The degree of inversion symmetry breaking is quantified using a mode-polarization vector analysis and is correlated with cation size mismatch, from which it is possible to deduce the acentric properties of 3D alkali-metal fluorocarbonates. PMID:24867361

  14. Multi-technique Characterization of Adsorbed Peptide and Protein Orientation: LK310 and Protein G B1

    SciTech Connect

    Baio, J.; Weidner, T; Samuel, N; McCrea, K; Baugh, L; Stayton, P; Castner, D

    2010-01-01

    The ability to orient biologically active proteins on surfaces is a major challenge in the design, construction, and successful deployment of many medical technologies. As methods to orient biomolecules are developed, it is also essential to develop techniques that can accurately determine the orientation and structure of these materials. In this study, two model protein and peptide systems are presented to highlight the strengths of three surface analysis techniques for characterizing protein films: time-of-flight secondary-ion mass spectrometry (ToF-SIMS), sum-frequency generation (SFG) vibrational spectroscopy, and near-edge x-ray absorption fine structure (NEXAFS) spectroscopy. First, the orientation of Protein G B1, a rigid 6 kDa domain covalently attached to a maleimide-functionalized self-assembled monolayer, was examined using ToF-SIMS. Although the thickness of the Protein G layer was similar to the ToF-SIMS sampling depth, orientation of Protein G was successfully determined by analyzing the C{sub 2}H{sub 5}S{sup +} intensity, a secondary-ion derived from a methionine residue located at one end of the protein. Next, the secondary structure of a 13-mer leucine-lysine peptide (LK{sub 310}) adsorbed onto hydrophilic quartz and hydrophobic fluorocarbon surfaces was examined. SFG spectra indicated that the peptide's lysine side chains were ordered on the quartz surface, while the peptide's leucine side chains were ordered on the fluorocarbon surface. NEXAFS results provided complementary information about the structure of the LK{sub 310} film and the orientations of amide bonds within the LK{sub 310} peptide.

  15. Self-Assembled Monolayers Generated from Unsymmetrical Partially Fluorinated Spiroalkanedithiols.

    PubMed

    Chinwangso, Pawilai; Lee, Han Ju; Lee, T Randall

    2015-12-15

    Self-assembled monolayers (SAMs) were prepared on gold substrates from an unsymmetrical partially fluorinated spiroalkanedithiol adsorbate with the specific structure of [CH3(CH2)7][CF3(CF2)7(CH2)8]C[CH2SH]2 (SADT) and compared to SAMs formed from the semifluorinated monothiol F8H10SH [CF3(CF2)7(CH2)10SH] of analogous chain length and n-octadecanethiol. The adsorbate with two alkyl chains, one terminally fluorinated and the other nonfluorinated, was designed to form monolayers in which the bulky helical fluorocarbon segments assemble on top of an underlying layer of well-packed trans-extended alkyl chains. Different combinations of deposition solvents and temperatures were used to produce the bidentate SAMs. Characterization of the resulting monolayers revealed that SAMs formed in DMF at room temperature allow complete binding of the sulfur headgroups to the surface and exhibit higher conformational order than those produced using alternative solvent/temperature combinations. The reduced film thicknesses and enhanced wettability of the SADT SAMs, as compared to the SAMs generated from F8H10SH, suggest loose packing and an increase in the tilt of the terminal fluorocarbon chain segments. Nevertheless, the density of the underlying hydrocarbon chains of the SADT SAMs was higher than that of the F8H10SH SAMs, owing to the double-chained structure of the new adsorbate. The conformational orders of the SAM systems were observed to decrease as follows: C18SH > F8H10SH > SADT. However, the SAMs formed from this new double-chained bidentate adsorbate in DMF expose a fluorinated interface with a relatively low surface roughness, as determined by contact-angle hysteresis. PMID:26575960

  16. Crystallization process of zircon and fergusonite during hydrothermal alteration in Nechalacho REE deposit, Thor Lake, Canada

    NASA Astrophysics Data System (ADS)

    Hoshino, M.; Watanabe, Y.; Murakami, H.; Kon, Y.; Tsunematsu, M.

    2012-04-01

    The core samples of two drill holes, which penetrate sub-horizontal mineralized horizons at Nechalacho REE deposit in the Proterozoic Thor Lake syenite, Canada, were studied in order to clarify magmatic and hydrothermal processes that enriched HFSE (e.g. Zr, Nb, Y and REE). Zircon is the most common REE minerals in Nechalacho REE deposit. The zircon is divided into five types as follows: Type-1 zircon occurs as single grain in phlogopite and the chondrite-normalized REE pattern is characterized by a steeply-rising slope from the LREE to the HREE with a positive Ce-anomaly and negative Eu-anomaly. This chemical characteristic is similar to that of igneous zircon. Type-2 zircon consists of HREE-rich magmatic porous core and LREE-Nb-F-rich hydrothermal rim. This type zircon is mostly included in phlogopite and fluorite, and occasionally in microcline. Type-3 zircon is characterized by euhedral to anhedral crystal, occurring in a complex intergrowth with REE fluorocarbonates. Type-3 zircons have high contents of REE, Nb and fluorine. Type-4 zircon consists of porous-core and -rim zones, but their chemical compositions are similar to each other. This type zircon is a subhedral crystal rimmed by fergusonite. Type-5 zircon is characterized by smaller, porous and subhedral to anhedral crystals. The interstices between small zircons are filled by fergusonite. Type-4 and -5 zircons show low REE and Nb contents. Occurrences of these five types of zircon are different according to the depth and degree of the alteration by hydrothermal solutions rich in F- and CO3 of the two drill holes, which permit a model for evolution of the zircon crystallization in Nechalacho REE deposit as follows: (1) type-1 (single magmatic zircon) is formed in miaskitic syenite. (2) LREE-Nb-F-rich hydrothermal zircon formed around HREE-rich magmatic zircon (type-2 zircon); (3) type-3 zircon crystallized thorough F and CO3-rich hydrothermal alteration of type-2 zircon which formed the complex intergrowth with REE fluorocarbonates; (4) the CO3-rich hydrothermal fluid corroded type-3, forming Nb-REE-poor zircons (type-3). Niobium and REE was no longer stable in the zircon structure and crystallized as fergusonite around the REE-Nb-leached zircon (type-4); (5) type-5 zircons are formed from more CO3-rich hydrothermal alteration of type-3 zircon. Therefore, type-4 and -5 zircons are often included in ankerite. Type 3-5 zircons at Nechalacho REE deposit were formed by leaching and/or dissolution of type-2 zircon in the presence of F- and/or CO3-rich hydrothermal fluid. The above mineral association indicates that three hydrothermal stages were present and related to HFSE enrichment in the Nechalacho REE deposit: (1) F-rich hydrothermal stage caused the crystallization of REE-Nb-rich zircon (type-2 rim and type-3), with abundant formation of phlogophite and fluorite, (2) F-CO3-rich hydrothermal stage led to the replacement of a part of REE-Nb-F-rich zircon by REE fluorocarbonate and (3) hydrothermal stage rich in CO3 resulted in crystallization of REE-Nb-F-poor zircon and fergusonite, with ankerite. Increases of HFSE contents, REE-Nb-F-poor zircon (type-4 and -5) and fergusonite contents during progress of hydrothermal alteration show that REE and Nb in hydrothermal fluid in the Nechalacho REE deposit were finally concentrated into fergusonite by way of zircon.

  17. Composite propellant aluminum agglomeration reduction using tailored Al/PTFE particles

    NASA Astrophysics Data System (ADS)

    Sippel, Travis R.

    Micron aluminum is widely used in propellants; however, performance could be significantly improved if ignition barriers could be disrupted and combustion tailored. In solid propellants for example, aluminum increases theoretical specific impulse performance, yet theoretical levels cannot be achieved largely because of two-phase flow losses. These losses could be reduced if particles quickly ignited, more gaseous products were produced, and if particle breakup occurred during combustion. To achieve altered aluminum ignition and particle combustion, this work explores the use of low level (10-30 wt.%) fluorocarbon (polytetrafluoroethylene (PTFE) or poly(carbon monofluoride) (PMF)) inclusion inside of aluminum via low or high energy mechanical activation. Aluminum/PTFE particles are found to be amenable to use in binder based energetics, having average particle sizes ranging from 15 to 78 μm, ~2-7 m2/g, specific surface area, and combustion enthalpies as high as 20.2 kJ/g. Differential scanning calorimetry (DSC) experiments indicate high energy MA reduces both reaction and oxidation onset to ~440 °C that is far below aluminum alone. Safety testing shows these particles have high electrostatic discharge (ESD) (89.9-108 mJ), impact (> 213 cm), and friction (> 360 N) ignition thresholds. The idea of further increasing reactivity and increasing particle combustion enthalpy is explored by reducing fluorocarbon inclusion content to 10 wt.% and through the use of the strained fluorocarbon PMF. Combustion enthalpy and average particle size range from 18.9 to 28.5 kJ/g and 23.0 to 67.5 μm, respectively and depend on MA intensity, duration, and inclusion level. Specific surface areas are high (5.3 to 34.8 m2/g) and as such, Al/PMF particles are appropriate for energetic applications not requiring a curable liquid binder. Mechanical activation reduces oxidation onset (DSC) from 555 to 480 °C (70/30 wt.%). Aluminum/PMF particles are sensitive to ESD (11.5-47.5 mJ) and some can be ignited via optical flash. Propellant aluminum agglomeration is assessed through replacement of reference aluminum powders (spherical, flake, or nanoscale) with Al/PTFE (90/10 or 70/30 wt.%) particles. The effects on burning rate, pressure dependence, and aluminum ignition, combustion, and agglomeration are quantified. Microscopic imaging shows tailored particles promptly ignite at the burning surface and appear to breakup into smaller particles. Replacement of spherical aluminum with Al/PTFE 70/30 wt.% also increases the pressure exponent from 0.36 to 0.58, which results in a 50% increase in propellant burning rate at 13.8 MPa. Combustion products were quench collected using a liquid-free technique at 2.1 and 6.9 MPa. Sizing of products indicates that composite particles result in nominally 25 μm coarse products, which are smaller than the original, average particle size and are also 66% smaller in diameter (96% by volume) than the 76 μm products collected from reference spherical aluminized propellant. Smaller diameter condensed phase products and more gaseous products will likely decrease two-phase flow loss and reduce slag accumulation in solid rocket motors.

  18. Efficient, environmentally acceptable method for waterproofing insulation material

    NASA Technical Reports Server (NTRS)

    Blohowiak, Kay Y. (Inventor); Krienke, Kenneth A. (Inventor); Olli, Larry K. (Inventor); Newquist, Charles W. (Inventor)

    2000-01-01

    A process of waterproofing alumina-rich or silica-rich fibrous thermal insulation material, the process including the steps of: (a) providing an alumina-rich or a silica-rich fibrous material; (b) providing a waterproofing solution including: (1) a carrier solvent selected from the group consisting of aliphatic alcohols having from 1C to 6C, water, and mixtures thereof; and (2) an alkoxysilane defined by the formula R.sub.4-x -Si-(O-R').sub.x where x is 1-3 and R is selected from the group consisting of alkyl groups having from 1C to 10C, hydrogen, or fluorocarbon groups having from 1F to 15F; and where O-R' is an alkoxy group having from 1C to 5C, or a mixture of alkoxysilanes defined by the above formula R.sub.4-x -Si-(O-R').sub.x ; and optionally (3) modifiers including acids, such as acetic acid or nitric acid, or bases, such as ammonium hydroxide, RNH.sub.2, R.sub.2 NH, or R.sub.3 N, or MOH, where R is selected from the group consisting of alkyl groups having from 1C to 10C or hydrogen, and where M=Na, Li, or K; (c) contacting the fibrous material with the waterproofing solution for a sufficient amount of time to waterproof the fibrous material; and (d) curing the coated fibrous material to render it sufficiently waterproof. A chemical solution for waterproofing alumina-rich or silica-rich fibrous thermal insulation materials, the solution including: (a) a carrier solvent selected from the group consisting of aliphatic alcohols having from 1C to 6C, water, and mixtures thereof; and (b) an alkoxysilane defined by the formula R.sub.4-x -Si-(O-R').sub.x where x is 1-3 and R is selected from the group consisting of alkyl groups having from 1C to 10C, hydrogen, or fluorocarbon groups having from 1F to 15F; and where O-R' is an alkoxy group having from 1C to 5C, or a mixture of alkoxysilanes defined by the above formula R.sub.4-x -Si-(O-R').sub.x ; and optionally (c) modifiers including acids, such as acetic acid or nitric acid, or bases, such as ammonium hydroxide, RNH.sub.2, R.sub.2 NH, or R.sub.3 N, or MOH, where R is selected from the group consisting of alkyl groups having from 1C to 10C or hydrogen, and where M=Na, Li, or K.

  19. Photochemical modification of polyethylene terephthalate surface

    NASA Astrophysics Data System (ADS)

    Zhu, Zhengmao

    The prospect of obtaining desired surface-mediated characteristics while retaining bulk-mediated physical properties and avoiding potential environmental issues with wet chemical technology lends considerable appeal to photochemical approaches to surface modification. We undertook a combined experimental and computational approach to investigate the effect of deep UV irradiation on the polyethylene terephthalate (PET) surface. Its response to 172 nm UV from a xenon examiner lamp in the absence of oxygen was characterized with X-ray Photoelectron Spectroscopy (XPS), Time of Flight/Secondary Ion Mass Spectrometry (ToF/SIMS), transmission infrared spectroscopy (IR), and Atomic Force Microscopy (AFM). The surface chemistry details suggested that the primary photochemical reactions involved a Norrish type I based decarbonylation and a Norrish type II process yielding terminal carboxylic acid groups, consistent with the possible photochemistry from n-pi* type lowest singlet excited states of PET according to the computational modeling results. By directly populating n-pi* type excited states, 172 nm UV promoted effective surface photochemistry of PET with further helps from the high UV absorptivity and the high surface mobility of the molecules. Utilizing this active surface radical chemistry, a new grafting strategy was developed to impart desirable functional properties to the surface. A broad range of grafting chemicals can be employed in their vapor forms, demonstrated with an alkene or an alkane. Surface analysis with XPS, ToF/SIMS, AFM, and water contact angle measurements confirmed the effectiveness of the approach, supporting the notion of the surface radical initiated processes. A potentially useful anti-stain/soil coating was developed by grafting with a fluorocarbon species. Surface analysis suggested that the grafted fluorocarbon formed a nano-scale self-assembled monolayer. The coating had a similar water contact angle as that of a pure fluoropolymer but a better oil repellency due to the special molecular orientation in the graft layer. A potential antimicrobial application was demonstrated with amine chemicals. Structure characterization and computational modeling results suggested that the photochemistry of the UV active grafting chemicals also played an important role in the grafting process. A double bond structure in the amine species protected the amine functional groups and the resulting coating demonstrated antimicrobial activity against E. coli.

  20. Damage by radicals and photons during plasma cleaning of porous low-k SiOCH. II. Water uptake and change in dielectric constant

    SciTech Connect

    Shoeb, Juline; Kushner, Mark J.

    2012-07-15

    Porous dielectric materials provide lower capacitances that reduce RC time delays in integrated circuits. Typical low-k materials include porous SiOCH-silicon dioxide with carbon groups, principally CH{sub 3}, lining the pores. With a high porosity, internally connected pores provide pathways for reactive species to enter into the material. Fluorocarbon plasmas are often used to etch SiOCH, a process that leaves a fluorocarbon polymer on the surface that must later be removed. During cleaning using Ar/O{sub 2} or He/H{sub 2} plasmas, reactions of radicals that diffuse into the SiOCH and photons that penetrate into the SiOCH can remove -CH{sub 3} groups. Due to its higher reactivity, cleaning with Ar/O{sub 2} plasmas removes more -CH{sub 3} groups than He/H{sub 2} plasmas, and so produce more free radical sites, such as -SiO{sub 2} Bullet (a -SiO{sub 2}-CH{sub 3} site with the -CH{sub 3} group removed).Upon exposure to humid air, these free radical sites can chemisorb H{sub 2}O to form hydrophilic Si-OH which can further physisorb H{sub 2}O through hydrogen bonding to form Si-OH(H{sub 2}O). With the high dielectric constant of water, even a small percentage of water uptake can significantly increase the effective dielectric constant of SiOCH. In this paper, we report on results from a computational investigation of the cleaning of SiOCH using Ar/O{sub 2} or He/H{sub 2} plasmas and subsequent exposure to humid air. The authors found that plasma cleaning with He/H{sub 2} mixtures produce less demethylation than cleaning with Ar/O{sub 2} plasmas, as so results in less water uptake, and a smaller increase in dielectric constant. The water that produces the increase in dielectric constant is roughly half chemisorbed and half physisorbed, the latter of which can be removed with mild heating. Sealing the pores with NH{sub 3} plasma treatment reduces water uptake and helps prevent the increase in dielectric constant.

  1. Synthesis of hybrid inorganic/organic nitric oxide-releasing silica nanoparticles for biomedical applications

    NASA Astrophysics Data System (ADS)

    Carpenter, Alexis Wells

    Nitric oxide (NO) is an endogenously produced free radical involved in a number of physiological processes. Thus, much research has focused on developing scaffolds that store and deliver exogenous NO. Herein, the synthesis of N-diazeniumdiolate-modified silica nanoparticles of various physical and chemical properties for biomedical applications is presented. To further develop NO-releasing silica particles for antimicrobial applications, a reverse microemulsion synthesis was designed to achieve nanoparticles of distinct sizes and similar NO release characteristics. Decreasing scaffold size resulted in improved bactericidal activity against Pseudomonas aeruginosa. Confocal microscopy revealed that the improved efficacy resulted from faster particle-bacterium association kinetics. To broaden the therapeutic potential of NO-releasing silica particles, strategies to tune NO release characteristics were evaluated. Initially, surface hydrophobicity and NO release kinetics were tuned by grafting hydrocarbon- and fluorocarbon-based silanes onto the surface of N-diazeniumdiolate-modified particles. The addition of fluorocarbons resulted in a 10x increase in the NO release half-life. The addition of short-chained hydrocarbons to the particle surface increased their stability in hydrophobic electrospun polyurethanes. Although NO release kinetics were longer than that of unmodified particles, durations were still limited to <7 days. An alternative strategy for increasing NO release duration involved directly stabilizing the N-diazeniumdiolate using O2-protecting groups. O2-Methoxymethyl 1-(4-(3-(trimethoxysilyl)propyl))piperazin-1-yl)diazen-1-ium-1,2-diolate (MOM-Pip/NO) was grafted onto mesoporous silica nanoparticles to yield scaffolds with an NO payload of 2.5 μmol NO/mg and an NO release half-life of 23 d. Doping the MOM-Pip/NO-modified particles into resin composites yielded antibacterial NO-releasing dental restorative materials. A 3-log reduction in viable adhered Streptococcus mutans was observed with the MOM-Pip/NO-doped composites compared to undoped controls. The greater chemical flexibility of macromolecular scaffolds is a major advantage over LMW NO donors as it allows for the incorporation of multiple functionalities onto a single scaffold. To demonstrate this advantage, dual functional particles were synthesized by covalently binding quaternary ammonium (QA) functionalities to the surface of NO-releasing silica particles. The QA functionality proved more effective against Staphylococcus aureus than P. aeruginosa, and increasing alkyl chain length correlated with increased efficacy. Nitric oxide-releasing QA-functionalized particles were found to be more effective against S. aureus compared to monofunctional particles.

  2. Elucidation of atomic scale mechanisms for polytetrafluoroethylene tribology using molecular dynamics simulation

    NASA Astrophysics Data System (ADS)

    Barry, Peter R.

    Polytetrafluoroethylene (PTFE) is a polymer that has been widely exploited commercially as a result of its low friction, 'non-stick' properties. The polymer has found usage as 'non-stick,' chemically resistant coatings for bearings, valves, rollers and pipe linings with applications in industries ranging from food and chemical processing to construction, automotive and aerospace. The major drawback of PTFE in low friction applications involves its excessive wear rate. For decades, scientists and engineers have sought to improve the polymer's wear resistance while maintaining its low sliding friction by reinforcing the polymer matrix with a host of filler materials ranging from fibril to particulate. In this study, a different approach is taken in which the atomic scale phenomena between two crystalline PTFE surfaces in sliding contact are examined. The goal is to obtain atomic-level insights into PTFE's low friction and high wear rate to aid in the designing of effective polymer based tribological composites for extreme condition applications. To accomplish this, several tribological conditions were varied. These included sliding direction of the two polymer surfaces with respect to their chain alignment, sliding velocity, degree of crystalline phase rigidity, interfacial contact pressure, sample temperature and the presence of fluorocarbon fluids between the two crystalline PTFE surfaces. From these studies, it was found that crystalline PTFE-PTFE sliding demonstrates friction anisotropy. Low friction and molecular wear was observed when sliding in the direction of the chain alignment with high friction and wear behavior dominating when sliding in a direction perpendicular to the chain alignment. For the range of cross-link density (average linear density of 6.2 to 11.1 A) and sliding rate (5 m/s to 20 m/s) explored, a significant change in friction behavior or wear mechanisms was not observed. Under conditions of increased normal load or low temperature however, the frictional force increased linearly. Additionally, the inclusion of fluorocarbon molecular fluids at the sliding interface between the two crystalline PTFE surfaces resulted in a significant decrease in both the friction and wear of the surfaces.

  3. Calibration and Sequence Development Status for the Sample Analysis at Mars Investigation on the Mars Science Laboratory

    NASA Technical Reports Server (NTRS)

    Mahaffy, Paul R.

    2012-01-01

    The measurement goals of the Sample Analysis at Mars (SAM) instrument suite on the "Curiosity" Rover of the Mars Science Laboratory (MSL) include chemical and isotopic analysis of organic and inorganic volatiles for both atmospheric and solid samples [1,2]. SAM directly supports the ambitious goals of the MSL mission to provide a quantitative assessment of habitability and preservation in Gale crater by means of a range of chemical and geological measurements [3]. The SAM FM combined calibration and environmental testing took place primarily in 2010 with a limited set of tests implemented after integration into the rover in January 2011. The scope of SAM FM testing was limited both to preserve SAM consumables such as life time of its electromechanical elements and to minimize the level of terrestrial contamination in the SAM instrument. A more comprehensive calibration of a SAM-like suite of instruments will be implemented in 2012 with calibration runs planned for the SAM testbed. The SAM Testbed is nearly identical to the SAM FM and operates in a ambient pressure chamber. The SAM Instrument Suite: SAM's instruments are a Quadrupole Mass Spectrometer (QMS), a 6-column Gas Chromatograph (GC), and a 2-channel Tunable Laser Spectrometer (TLS). Gas Chromatography Mass Spectrometry is designed for identification of even trace organic compounds. The TLS [5] secures the C, H, and O isotopic composition in carbon dioxide, water, and methane. Sieved materials are delivered from the MSL sample acquisition and processing system to one of68 cups of the Sample Manipulation System (SMS). 59 of these cups are fabricated from inert quartz. After sample delivery, a cup is inserted into one of 2 ovens for evolved gas analysis (EGA ambient to >9500C) by the QMS and TLS. A portion of the gas released can be trapped and subsequently analyzed by GCMS. Nine sealed cups contain liquid solvents and chemical derivatization or thermochemolysis agents to extract and transform polar molecules such as amino acids, nucleobases, and carboxylic acids into compounds that are sufficiently volatile to transmit through the GC columns. The remaining 6 cups contain calibrants. SAM FM Calibration Overview: The SAM FM calibration in the Mars chamber employed a variety of pure gases, gas mixtures, and solid materials. Isotope calibration runs for the TLS utilized 13C enriched C02 standards and 0 enriched CH4. A variety of fluorocarbon compounds that spanned the entire mass range of the QMS as well as C3-C6 hydrocarbons were utilized for calibration of the GCMS. Solid samples consisting of a mixture of calcite, melanterite, and inert silica glass either doped or not with fluorocarbons were introduced into the SAM FM cups through the SAM inlet funnel/tube system.

  4. Geochemical and mineralogical characteristics of ion-adsorption type REE mineralization in Phuket, Thailand

    NASA Astrophysics Data System (ADS)

    Sanematsu, Kenzo; Kon, Yoshiaki; Imai, Akira; Watanabe, Koichiro; Watanabe, Yasushi

    2013-04-01

    Geochemical and mineralogical studies were conducted on the 12-m-thick weathering profile of the Kata Beach granite in Phuket, Thailand, in order to reveal the transport and adsorption of rare earth elements (REE) related to the ion-adsorption type mineralization. The parent rock is ilmenite-series biotite granite with transitional characteristics from I type to S type, abundant in REE (592 ppm). REE are contained dominantly in fluorocarbonate as well as in allanite, titanite, apatite, and zircon. The chondrite-normalized REE pattern of the parent granite indicates enrichment of LREE relative to HREE and no significant Ce anomaly. The upper part of the weathering profile from the surface to 4.5 m depth is mostly characterized by positive Ce anomaly, showing lower REE contents ranging from 174 to 548 ppm and lower percentages of adsorbed REE from 34% to 68% compared with the parent granite. In contrast, the lower part of the profile from 4.5 to 12 m depth is characterized by negative Ce anomaly, showing higher REE contents ranging from 578 to 1,084 ppm and higher percentages from 53% to 85%. The negative Ce anomaly and enrichment of REE in the lower part of the profile suggest that acidic soil water in an oxidizing condition in the upper part mostly immobilized Ce4+ as CeO2 and transported REE3+ downward to the lower part of the profile. The transported REE3+ were adsorbed onto weathering products or distributed to secondary minerals such as rhabdophane. The immobilization of REE results from the increase of pH due to the contact with higher pH groundwater. Since the majority of REE in the weathered granite are present in the ion-adsorption fraction with negative Ce anomaly, the percentages of adsorbed REE are positively correlated with the whole-rock negative Ce anomaly. The result of this study suggests that the ion-adsorption type REE mineralization is identified by the occurrence of easily soluble REE fluorocarbonate and whole-rock negative Ce anomaly of weathered granite. Although fractionation of REE in weathered granite is controlled by the occurrence of REE-bearing minerals and adsorption by weathering products, the ion-adsorption fraction tends to be enriched in LREE relative to weathered granite.

  5. The Nolans Bore rare-earth element-phosphorus-uranium mineral system: geology, origin and post-depositional modifications

    NASA Astrophysics Data System (ADS)

    Huston, David L.; Maas, Roland; Cross, Andrew; Hussey, Kelvin J.; Mernagh, Terrence P.; Fraser, Geoff; Champion, David C.

    2016-01-01

    Nolans Bore is a rare-earth element (REE)-U-P fluorapatite vein deposit hosted mostly by the ~1805 Ma Boothby Orthogneiss in the Aileron Province, Northern Territory, Australia. The fluorapatite veins are complex, with two stages: (1) massive to granular fluorapatite with inclusions of REE silicates, phosphates and (fluoro)carbonates, and (2) calcite-allanite with accessory REE-bearing phosphate and (fluoro)carbonate minerals that vein and brecciate the earlier stage. The veins are locally accompanied by narrow skarn-like (garnet-diopside-amphibole) wall rock alteration zones. SHRIMP Th-Pb analyses of allanite yielded an age of 1525 ± 18 Ma, interpreted as the minimum age of mineralisation. The maximum age is provided by a ~1550 Ma SHRIMP U-Pb age for a pegmatite that predates the fluorapatite veins. Other isotopic systems yielded ages from ~1443 to ~345 Ma, implying significant post-depositional isotopic disturbance. Calculation of initial ɛNd and 87Sr/86Sr at 1525 Ma and stable isotope data are consistent with an enriched mantle or lower crust source, although post-depositional disturbance is likely. Processes leading to formation of Nolans Bore began with north-dipping subduction along the south margin of the Aileron Province at 1820-1750 Ma, producing a metasomatised, volatile-rich, lithospheric mantle wedge. About 200 million years later, near the end of the Chewings Orogeny, this reservoir and/or the lower crust sourced alkaline low-degree partial melts which passed into the mid- and upper-crust. Fluids derived from these melts, which may have included phosphatic melts, eventually deposited the Nolans Bore fluorapatite veins due to fluid-rock interaction, cooling, depressurisation and/or fluid mixing. Owing to its size and high concentration of Th (2500 ppm), in situ radiogenic heating caused significant recrystallisation and isotopic resetting. The system finally cooled below 300 °C at ~370 Ma, possibly in response to unroofing during the Alice Springs Orogeny. Surface exposure and weathering of fluorapatite produced acidic fluids and intense, near-surface kaolinitised zones that include high-grade, supergene-enriched cheralite-rich ores.

  6. Chemical selectivity in micellar electrokinetic chromatography: characterization of solute-micelle interactions for classification of surfactants.

    PubMed

    Yang, S; Khaledi, M G

    1995-02-01

    The influence of surfactant type on migration behavior and chemical selectivity in micellar electrokinetic chromatography (MEKC) is investigated through linear solvation energy relationships (LSER) and functional group selectivities. In LSER modeling, solutes' capacity factors are correlated with their structural descriptors such as size, dipolarity, and hydrogen-bonding abilities. Using the LSER methodology, useful information about the nature of solute interactions with different types of surfactant aggregates can be obtained since capacity factor in MEKC is directly related to solute distribution between the bulk aqueous solvent and micelles. High correlations were observed for different LSER models of migration behavior in MEKC for a group of 60 uncharged aromatic compounds of non-hydrogen bonding (NHB), hydrogen-bonding acceptor (HBA) bases, and hydrogen-bonding donor (HBD) acids. In two anionic, hydrocarbon micellar systems of sodium dodecyl sulfate (SDS) and sodium cholate (SC), retention is primarily influenced by the size of molecules and their hydrogen bond accepting basicity. Their dipolarity/polarizability and hydrogen bond donating acidity play minor roles. Capacity factors of solutes in SDS and SC systems increase with their size and decrease for stronger hydrogen bond acceptor bases. These results are similar to those observed for other systems where hydrophobic interactions play a major role, e.g., solute distribution in the 1-octanol-water solvent system or retention in reversed phase LC. In MEKC with an anionic fluorocarbon surfactant, lithium perfluorooctanesulfonate (LiPFOS), however, size and solute HBD acidity are the two predominant factors. The LSER results indicate that compounds find the SDS micellar environments slightly less cohesive (i.e., more apolar) than the SC micelles, while the LiPFOS micelles are the most cohesive among the three surfactant aggregates and 1-octanol provides the least cohesive environment. The fluorocarbon micelles of LiPFOS, on the other hand, are the strongest hydrogen bond donor acids, followed by SDS, SC, and 1-octanol, respectively. The SC micelles have the most hydrogen bond acceptor basic characteristics, followed by 1-octanol, SDS, and LiPFOS micelles. It can be concluded that selectivity differences between these surfactant types in MEKC is primarily due to hydrogen-bonding interactions rather than the dipolar interactions. Comparing the perfluorinated and the hydrocarbon surfactants, even solute size can play a role in selective migration patterns. In addition, information from polar and hydrophobic group selectivities confirm the LSER conclusions about the underlying interactions that control migration behavior and chemical selectivity in MEKC.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:7893000

  7. Multi-functional Textiles for Military Applications

    NASA Astrophysics Data System (ADS)

    Malshe, Priyadarshini

    The objective of this research was to develop the standard rip-stop weave military uniform fabric made of 50/50 nylon/cotton (NyCo) to achieve a repellent front surface and an antibacterial bulk for protection from chemical-biological warfare agents. Diallyldimethylammonium chloride (DADMAC), a quaternary ammonium salt monomer was graft polymerized on NyCo fabric to impart antimicrobial capability using atmospheric pressure glow discharge plasma. Plasma was used to induce free radical chain polymerization of the DADMAC monomer to introduce a graft polymerized network on the fabric with durable antimicrobial properties. Pentaerythritol tertraacrylate was used as a cross-linking agent to obtain a highly cross-linked, durable polymer network. The presence of polyDADMAC on the fabric surface was confirmed using acid dye staining, SEM, and TOF-SIMS. Antibacterial performance was evaluated using standard AATCC test method 100 for both gram positive and gram negative bacteria. Results showed 99.9% reduction in the bacterial activities of K. pneumoniae and S. aureus. To achieve repellency on NyCo front surface, an environmentally benign C6 fluorocarbon monomer, 2-(perfluorohexyl) ethyl acrylate was graft polymerized using plasma on the front surface of the NyCo fabric which was already grafted with polyDADMAC for anti-microbial properties. The surface was characterized by IR spectroscopy and XPS. The presence of fluorine on the surface was mapped and confirmed by TOF-SIMS. SEM images showed a uniform layer of fluorocarbon polymer on the fiber surface. High water contact angle of 144° was obtained on the surface. The surface also achieved a high AATCC Test Method 193 rating of 9 and AATCC Test Method 118 rating of 5, indicating that the surface could repel a fluid with surface tension as low as 24 dynes/cm. Appropriate experimental designs and statistical modeling of data helped identify the experimental space and optimal factor combinations for best response. The study helped create a multi-functional fabric with an anti-bacterial bulk, hydrophilic back surface and repellent front surface for enhanced protective and aesthetic values.

  8. O-ring sealing verification for the space shuttle redesign solid rocket motor

    NASA Technical Reports Server (NTRS)

    Lach, Cynthia L.

    1989-01-01

    As a part of the redesign of the Space Shuttle Solid Rocket Motor, the field and nozzle-to-case joints were redesigned to minimize the dynamic flexure caused by internal motor pressurization during ignition. The O-ring seals and glands for the joints were designed to accommodate both structural deflections and to promote pressure assistance. A test program was conducted to determine if a fluorocarbon elastomeric O-ring could meet this criteria in the redesigned gland. Resiliency tests were used to investigate the O-ring response to gap motion while static seal tests were used to verify design criteria of pressure assistance for sealing. All tests were conducted in face seal fixtures mounted in servo-hydraulic test machines. The resiliency of the O-ring was found to be extremely sensitive to the effects of temperature. The External Tank/Solid Rocket Booster attach strut loads had a negligible affect on the ability of the O-ring to track the simulated SRB field joint deflection. In the static pressure-assisted seal tests, as long as physical contact was maintained between the O-ring and the gland sealing surface, pressure assistance induced instantaneous sealing.

  9. Uncertainties in Air Exchange using Continuous-Injection, Long-Term Sampling Tracer-Gas Methods

    SciTech Connect

    Sherman, Max H.; Walker, Iain S.; Lunden, Melissa M.

    2013-12-01

    The PerFluorocarbon Tracer (PFT) method is a low-cost approach commonly used for measuring air exchange in buildings using tracer gases. It is a specific application of the more general Continuous-Injection, Long-Term Sampling (CILTS) method. The technique is widely used but there has been little work on understanding the uncertainties (both precision and bias) associated with its use, particularly given that it is typically deployed by untrained or lightly trained people to minimize experimental costs. In this article we will conduct a first-principles error analysis to estimate the uncertainties and then compare that analysis to CILTS measurements that were over-sampled, through the use of multiple tracers and emitter and sampler distribution patterns, in three houses. We find that the CILTS method can have an overall uncertainty of 10-15percent in ideal circumstances, but that even in highly controlled field experiments done by trained experimenters expected uncertainties are about 20percent. In addition, there are many field conditions (such as open windows) where CILTS is not likely to provide any quantitative data. Even avoiding the worst situations of assumption violations CILTS should be considered as having a something like a ?factor of two? uncertainty for the broad field trials that it is typically used in. We provide guidance on how to deploy CILTS and design the experiment to minimize uncertainties.

  10. Description and validation of the Little correlation for boiling zeotropic mixtures in horizontal tubes from cryogenic to room temperature

    NASA Astrophysics Data System (ADS)

    Barraza, R.; Nellis, G.; Klein, S.; Reindl, D.

    2015-12-01

    The use of mixed gas working fluids has become common in Joule-Thomson (JT) type cryocoolers for a variety of applications operating in temperatures ranging from 80 to 230 K. The thermal efficiency of mixed gas JT cryocoolers is dependent on the optimization of the gas mixture composition. Most optimization methodologies focus on thermodynamic criteria of the cycle because there are very little data or theory currently available regarding the heat transfer coefficients associated with these multi-component mixtures in two-phase regimes at cryogenic temperatures. A generally accepted correlation to predict the local heat transfer coefficient (htc) for mixtures during the boiling process does not exist. Little [1] proposed a correlation to be used on horizontal tubes that shows good agreement with Nellis et al. [2] experimental data of nitrogen-hydrocarbon mixtures. However, it is not clearly shown how the correlation is obtained and how it should be applied. This paper provides a more complete description of the Little correlation and also expands its validation using the experimental data provided by Barraza [3]. The new experimental data include measurements of the local heat transfer coefficient for mixtures comprising 2 component (binary) up to 5 components in the temperature range between 100 K and room temperature. These mixtures are formed from nitrogen-hydrocarbon and argon-fluorocarbon mixtures and evaporate in horizontal tubes with diameters from 0.5 to 3.0 mm for different heat flux, mass flux, evaporating pressure, and composition.

  11. New concepts for refrigerant leak detection and mixture measurement

    NASA Astrophysics Data System (ADS)

    Chen, F. C.; Allman, S. L.; Chen, C. H.

    Since the discovery that chlorofluorocarbons (CFC's) destroy the ozone layer, the need to reduce the release of these refrigerants into the environment has become critical. A total ban of ozone-depleting CFC's is expected within a few years, and hydrofluorocarbons (HFC's) and fluorocarbons (FC's) and their mixtures are expected to be used during a transition period. Several HFC and FC refrigerants are currently being considered as CFC substitutes. The electronic refrigerant leak detectors currently being considered as CFC substitutes. The electronic refrigerant leak detectors currently on the market were developed to detect CFC's and are not as sensitive to HFC's. Although incremental improvement can be made to these devices to detect HFC's, they often lead to increased false signals. Also, there is no simple device available to measure the composition of a refrigerant mixture. The authors present two new concepts to aid in the development of two portable instruments that can be used for HFC leak detection and for quantitative measurement of refrigerant mixture compositions. The development of simple, easy-to-use portable leak detectors and refrigerant mixture meters is essential to the wide use of alternative refrigerants in industry.

  12. A Roof for the Lion's House

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Fans of the National Football League's Detroit Lions don't worry about gameday weather. Their magnificent new Pontiac Stadium has a domed, air-supported, fabric roof that admits light but protects the playing field and patrons from the elements. The 80,000-seat "Silverdome" is the world's largest fabric-covered structure-and aerospace technology played an important part in its construction. The key to economical construction of the Silverdome-and many other types of buildings-is a spinoff of fiber glass Beta yarn coated with Teflon TFE fluorocarbon resin. The big advance it offers is permanency. Fabric structures-tents, for example have been around since the earliest years of human civilization. But their coverings-hides, canvas and more recently plastics-were considered temporary; though tough, these fabrics were subject to weather deterioration. Teflon TFE-coated Beta Fiberglas is virtually impervious to the effects of weather and sunlight and it won't stretch, shrink, mildew or rot, thus has exceptional longevity; it is also very strong, lightweight, flame resistant and requires no periodic cleaning, because dirt will not stick to the surface of Teflon TFE. And to top all that, it costs only 30 to 40 percent as much as conventional roofing.

  13. Discrete elements for 3D microfluidics.

    PubMed

    Bhargava, Krisna C; Thompson, Bryant; Malmstadt, Noah

    2014-10-21

    Microfluidic systems are rapidly becoming commonplace tools for high-precision materials synthesis, biochemical sample preparation, and biophysical analysis. Typically, microfluidic systems are constructed in monolithic form by means of microfabrication and, increasingly, by additive techniques. These methods restrict the design and assembly of truly complex systems by placing unnecessary emphasis on complete functional integration of operational elements in a planar environment. Here, we present a solution based on discrete elements that liberates designers to build large-scale microfluidic systems in three dimensions that are modular, diverse, and predictable by simple network analysis techniques. We develop a sample library of standardized components and connectors manufactured using stereolithography. We predict and validate the flow characteristics of these individual components to design and construct a tunable concentration gradient generator with a scalable number of parallel outputs. We show that these systems are rapidly reconfigurable by constructing three variations of a device for generating monodisperse microdroplets in two distinct size regimes and in a high-throughput mode by simple replacement of emulsifier subcircuits. Finally, we demonstrate the capability for active process monitoring by constructing an optical sensing element for detecting water droplets in a fluorocarbon stream and quantifying their size and frequency. By moving away from large-scale integration toward standardized discrete elements, we demonstrate the potential to reduce the practice of designing and assembling complex 3D microfluidic circuits to a methodology comparable to that found in the electronics industry. PMID:25246553

  14. Hierarchical structures of AlOOH nanoflakes nested on Si nanopillars with anti-reflectance and superhydrophobicity.

    PubMed

    Yu, Eusun; Lee, Heon Ju; Ko, Tae-Jun; Kim, Seong Jin; Lee, Kwang-Ryeol; Oh, Kyu Hwan; Moon, Myoung-Woon

    2013-10-21

    A novel method to fabricate ultra-low reflective Si surfaces with nanoscale hierarchical structures is developed by the combination of AlOOH or boehmite nanoflakes nested on plasma-etched Si nanopillars. Using CF4 plasma etching, Si surfaces are nanostructured with pillar-like structures by selective etching with self-masking by fluorocarbon residues. AlOOH nanoflakes are formed by Al thin film coating with various thicknesses and subsequent immersion in boiling water, which induces the formation of nanoscale flakes through the hydrolysis reaction. AlOOH nanoflakes are formed on Si nanopillared surfaces for hierarchical structures, which are coated with a low-surface-energy material, resulting in a higher water wetting angle of over 150 and a very low contact angle hysteresis of less than 5, and implying a self-cleaning surface. Reflectance reduced to 5.18% on average on hierarchical nanostructures in comparison to 9.63% on the Si nanopillar surfaces only. We found that Si nanopillars reduced reflection for wavelengths ranging from 200 to 1200 nm while AlOOH nanoflakes reduced reflection for wavelengths longer than 600 nm. PMID:24057013

  15. Hierarchical structures of AlOOH nanoflakes nested on Si nanopillars with anti-reflectance and superhydrophobicity

    NASA Astrophysics Data System (ADS)

    Yu, Eusun; Lee, Heon Ju; Ko, Tae-Jun; Kim, Seong Jin; Lee, Kwang-Ryeol; Oh, Kyu Hwan; Moon, Myoung-Woon

    2013-09-01

    A novel method to fabricate ultra-low reflective Si surfaces with nanoscale hierarchical structures is developed by the combination of AlOOH or boehmite nanoflakes nested on plasma-etched Si nanopillars. Using CF4 plasma etching, Si surfaces are nanostructured with pillar-like structures by selective etching with self-masking by fluorocarbon residues. AlOOH nanoflakes are formed by Al thin film coating with various thicknesses and subsequent immersion in boiling water, which induces the formation of nanoscale flakes through the hydrolysis reaction. AlOOH nanoflakes are formed on Si nanopillared surfaces for hierarchical structures, which are coated with a low-surface-energy material, resulting in a higher water wetting angle of over 150 and a very low contact angle hysteresis of less than 5, and implying a self-cleaning surface. Reflectance reduced to 5.18% on average on hierarchical nanostructures in comparison to 9.63% on the Si nanopillar surfaces only. We found that Si nanopillars reduced reflection for wavelengths ranging from 200 to 1200 nm while AlOOH nanoflakes reduced reflection for wavelengths longer than 600 nm.

  16. Nuclear criticality safety assessment of the proposed CFC replacement coolants

    SciTech Connect

    Jordan, W.C.; Dyer, H.R.

    1993-12-01

    The neutron multiplication characteristics of refrigerant-114 (R-114) and proposed replacement coolants perfluorobutane (C{sub 4}F{sub 10}) and cycloperfluorobutane C{sub 4}F{sub 8}) have been compared by evaluating the infinite media multiplication factors of UF{sub 6}/H/coolant systems and by replacement calculations considering a 10-MW freezer/sublimer. The results of these comparisons demonstrate that R-114 is a neutron absorber, due to its chlorine content, and that the alternative fluorocarbon coolants are neutron moderators. Estimates of critical spherical geometries considering mixtures of UF{sub 6}/HF/C{sub 4}F{sub 10} indicate that the flourocarbon-moderated systems are large compared with water-moderated systems. The freezer/sublimer calculations indicate that the alternative coolants are more reactive than R-114, but that the reactivity remains significantly below the condition of water in the tubes, which was a limiting condition. Based on these results, the alternative coolants appear to be acceptable; however, several follow-up tasks have been recommended, and additional evaluation will be required on an individual equipment basis.

  17. Design and analysis of a 5-MW vertical-fluted-tube condenser for geothermal applications

    SciTech Connect

    Llewellyn, G.H.

    1982-03-01

    The design and analysis of an industtial-sized vertical-fluted-tube condenser. The condenser is used to condense superheated isobutane vapor discharged from a power turbine in a geothermal test facility operated for the US Department of Energy. The 5-MW condenser has 1150 coolant tubes in a four-pass configuration with a total heat transfer area of 725 m/sup 2/ (7800 ft/sup 2/). The unit is being tested at the Geothermal Components Test Facility in the Imperial Valley of East Mesa, California. The condenser design is based on previous experimental research work done at the Oak Ridge National Laboratory on condensing refrigerants on a wide variety of single vertical tubes. Condensing film coefficients obtained on the high-performance vertical fluted tubes in condensing refrigerants are as much as seven times greater than those obtained with vertical smooth tubes that have the same diameter and length. The overall heat transfer performance expected from the fluted tube condenser is four to five times the heat transfer obtained from the identical units employing smooth tubes. Fluted tube condensers also have other direct applications in the Ocean Thermal Energy Conversion (OTEC) program in condensing ammonia, in the petroleum industry in condensing light hydrocarbons, and in the air conditioning and refrigeration industry in condensing fluorocarbon vapors.

  18. Experimental Study on States of Liquid Film on Heat Transfer Surface Inside a Horizontal Spirally Grooved Tube during Evaporation

    NASA Astrophysics Data System (ADS)

    Higashiiue, Shinya; Momoki, Satoru; Shigechi, Toru; Mori, Hideo; Yamaguchi, Tomohiko

    This paper presents a prediction method of flow regimes during evaporation of pure refrigerants in a horizontal spirally grooved steel tube with 12mm in average inner diameter. Circumferential temperature distributions on the external surface of the tube and boiling heat transfer coefficients were obtained through the experiments on the flow boiling heat transfer using two kinds of fluorocarbon refrigerants, HCFC123 and HCFC22. Based on the temperature distributions and the characteristics of heat transfer coefficient against vapor quality, we discussed the conditions of liquid film formed on the heat transfer surface. The experimental data were classified into four kinds of flow regimes according to the viewpoint on the liquid film conditions and heat transfer characteristics: annular flow, annular flow with liquid meniscus, separated flow with liquid meniscus and separated flow with dry surface. In order to predict the transition quality from separated flow to annular flow, we developed the correlation for border angle of well-wetted perimeter for the present grooved tube based on the Mori et al. correlation proposed for smooth tubes. The correlation for the transitional quality between separated flow with dry surface and separated flow with liquid meniscus was developed empirically as well as the correlation for the transient transitional quality between annular flow and annular flow with liquid meniscus.

  19. Regulation of adhesion behavior of murine macrophage using supported lipid membranes displaying tunable mannose domains.

    PubMed

    Kaindl, T; Oelke, J; Pasc, A; Kaufmann, S; Konovalov, O V; Funari, S S; Engel, U; Wixforth, A; Tanaka, M

    2010-07-21

    Highly uniform, strongly correlated domains of synthetically designed lipids can be incorporated into supported lipid membranes. The systematic characterization of membranes displaying a variety of domains revealed that the equilibrium size of domains significantly depends on the length of fluorocarbon chains, which can be quantitatively interpreted within the framework of an equivalent dipole model. A mono-dispersive, narrow size distribution of the domains enables us to treat the inter-domain correlations as two-dimensional colloidal crystallization and calculate the potentials of mean force. The obtained results demonstrated that both size and inter-domain correlation can precisely be controlled by the molecular structures. By coupling ?-D-mannose to lipid head groups, we studied the adhesion behavior of the murine macrophage (J774A.1) on supported membranes. Specific adhesion and spreading of macrophages showed a clear dependence on the density of functional lipids. The obtained results suggest that such synthetic lipid domains can be used as a defined platform to study how cells sense the size and distribution of functional molecules during adhesion and spreading. PMID:21399291

  20. Bulk plasma fragmentation in a C4F8 inductively coupled plasma: A hybrid modeling study

    NASA Astrophysics Data System (ADS)

    Zhao, Shu-Xia; Zhang, Yu-Ru; Gao, Fei; Wang, You-Nian; Bogaerts, Annemie

    2015-06-01

    A hybrid model is used to investigate the fragmentation of C4F8 inductive discharges. Indeed, the resulting reactive species are crucial for the optimization of the Si-based etching process, since they determine the mechanisms of fluorination, polymerization, and sputtering. In this paper, we present the dissociation degree, the density ratio of F vs. CxFy (i.e., fluorocarbon (fc) neutrals), the neutral vs. positive ion density ratio, details on the neutral and ion components, and fractions of various fc neutrals (or ions) in the total fc neutral (or ion) density in a C4F8 inductively coupled plasma source, as well as the effect of pressure and power on these results. To analyze the fragmentation behavior, the electron density and temperature and electron energy probability function (EEPF) are investigated. Moreover, the main electron-impact generation sources for all considered neutrals and ions are determined from the complicated C4F8 reaction set used in the model. The C4F8 plasma fragmentation is explained, taking into account many factors, such as the EEPF characteristics, the dominance of primary and secondary processes, and the thresholds of dissociation and ionization. The simulation results are compared with experiments from literature, and reasonable agreement is obtained. Some discrepancies are observed, which can probably be attributed to the simplified polymer surface kinetics assumed in the model.