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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. 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.

  3. Metals plated on fluorocarbon polymers

    NASA Technical Reports Server (NTRS)

    Ford, H.; Krasinsky, J. B.; Vango, S. P.

    1964-01-01

    Electroplating lead on fluorocarbon polymer parts is accomplished by etching the parts to be plated with sodium, followed by successive depositions of silver and lead from ultrasonically agitated plating solutions. Metals other than lead may be electroplated on the silvered parts.

  4. Molecular origins of fluorocarbon hydrophobicity

    PubMed Central

    Dalvi, Vishwanath H.; Rossky, Peter J.

    2010-01-01

    We have undertaken atomistic molecular simulations to systematically determine the structural contributions to the hydrophobicity of fluorinated solutes and surfaces compared to the corresponding hydrocarbon, yielding a unified explanation for these phenomena. We have transformed a short chain alkane, n-octane, to n-perfluorooctane in stages. The free-energy changes and the entropic components calculated for each transformation stage yield considerable insight into the relevant physics. To evaluate the effect of a surface, we have also conducted contact-angle simulations of water on self-assembled monolayers of hydrocarbon and fluorocarbon thiols. Our results, which are consistent with experimental observations, indicate that the hydrophobicity of the fluorocarbon, whether the interaction with water is as solute or as surface, is due to its “fatness.” In solution, the extra work of cavity formation to accommodate a fluorocarbon, compared to a hydrocarbon, is not offset by enhanced energetic interactions with water. The enhanced hydrophobicity of fluorinated surfaces arises because fluorocarbons pack less densely on surfaces leading to poorer van der Waals interactions with water. We find that interaction of water with a hydrophobic solute/surface is primarily a function of van der Waals interactions and is substantially independent of electrostatic interactions. This independence is primarily due to the strong tendency of water at room temperature to maintain its hydrogen bonding network structure at an interface lacking hydrophilic sites. PMID:20643968

  5. Fluorinated diamond bonded in fluorocarbon resin

    DOEpatents

    Taylor, Gene W.

    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. 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.

  7. Fluorocarbon nanodrops as acoustic temperature probes.

    PubMed

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

    2015-10-06

    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.

  8. 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.

  9. Fluorocarbon adsorption in hierarchical porous frameworks

    NASA Astrophysics Data System (ADS)

    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.

    2014-07-01

    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.

  10. 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.

  11. 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.

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

    DOEpatents

    Taylor, Gene W.; Roybal, Herman E.

    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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. METHOD FOR DETERMINING THE STABILITY OF FLUOROCARBON IOLS

    DOEpatents

    Sheldon, Z.D.; Haendler, H.M.

    1959-07-21

    A method of determining the stability of a fluorocarbon oil to uranium hexafluoride is presented. The method comprises reacting a weighed sample of the oil with condensed uranium hexafluoride in a reaction zone and titrating the amount of uranium tetrafluoride produced with potassium dichromate.

  18. 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.

  19. 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.

  20. 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.

  1. A preliminary petrogenetic grid for REE fluorocarbonates and associated minerals

    NASA Astrophysics Data System (ADS)

    Williams-Jones, Anthony E.; Wood, Scott A.

    1992-02-01

    The bulk of the world's economic LREE reserves occur as fluorocarbonate minerals, notably bastnaesite. However, despite the importance of these minerals, very little is known about the physicochemical conditions controlling their formation. In this paper we attempt to partly redress this deficiency by qualitatively determining P- T and compositional relationships for part of the system Ln(CO 3)F-CaCO 3-F 2(CO 3) -1-H 2O, including the minerals fluorite, calcite, bastnaesite, parisite, synchysite and fluocerite. This degenerate ( n + 3)-phase multisystem has 23 possible base P- T topologies, plus their mirror images and trivial conjugates, from which we have been able to select a single probable stable topology using a combination of published experimental phase equilibrium data, molar volume and entropy estimates and natural assemblage data. Compositional relationships in the system have been established by constructing log ( aca2+ · aF-2) vs. log ( a F -2/a CO 32-) diagrams for each of the stable divariant regions shown on the P- T net. Important conclusions of the study with respect to P- T relationships are (1) that all of the above REE-fluorocarbonate minerals can form at comparatively low pressure and temperature; (2) that bastnaesite + fluorite is a low-temperature assemblage and, in the presence of synchysite or calcite, is also restricted to low or high pressure, respectively; (3) that parisite + fluorite is stable to higher temperatures; (4) that bastnaesite + synchysite + calcite is restricted to high P- T conditions; (5) that parisite reacts to form bastnaesite and calcite at high temperatures (<620°C at 1 kb); and (6) that bastnaesite-(La) decomposes by a decarbonation reaction at temperatures <750°C at 1 kb and at lower temperatures with decreasing ionic radius of the lanthanide. The principal conclusions with respect to compositional relationships are (1) that transformations among the REE fluorocarbonates cannot occur through changes in F

  2. Advanced fluorocarbon-based systems for oxygen and drug delivery, and diagnosis.

    PubMed

    Riess, J G; Krafft, M P

    1997-01-01

    Fluorocarbons and fluorocarbon-derived materials constitute a vast family of synthetic components that have a range of remarkable properties including exceptional chemical and biological inertness, gas-dissolving capacity, low surface tension, high fluidity, excellent spreading characteristics, unique hydro- and lipophobicity, high density, absence of protons, and magnetic susceptibility close to that of water. These properties lead to a diversity of products and applications as illustrated by those products that are already in advanced clinical trials, which comprise: 1) an injectable oxygen carrier, i.e. blood substitute, consisting of a fluorocarbon-in-water emulsion for use in surgery to alleviate the problems raised by the transfusion of homologous blood; the same emulsion is also being evaluated with cardiopulmonary bypass patients; 2) a neat fluorocarbon for treatment of acute respiratory failure by liquid ventilation; and 3) fluorocarbon-based or stabilized gas bubbles to be used as contrast agents for the assessment of heart function and detection of perfusion defects by ultrasound imaging. Proper selection of the fluorocarbon best suited for the intended application, formulation optimization, and advanced stabilization and processing procedures led to effective, ready-for-use products with minimal side-effects. Further highly fluorinated materials, including amphiphiles and various fluorocarbon-based colloidal systems that have potential as pulmonary, topical and ophthalmological drug delivery agents, and as skin protection barriers, are now being investigated. Such systems include drug-in-fluorocarbon suspensions, reverse water-in-fluorocarbon emulsions, oil-in-fluorocarbon emulsions, multiple emulsions, microemulsions, fluorocarbon gels, fluorinated liposomes, fluorinated tubules and other novel supramolecular systems.

  3. Robust Ultralow-k Dielectric (Fluorocarbon) Deposition by Microwave Plasma-Enhanced Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Kikuchi, Yoshiyuki; Miyatani, Kotaro; Kobayashi, Yasuo; Kawamura, Kohei; Nemoto, Takenao; Nakamura, Masahiro; Matsumoto, Hirokazu; Ito, Azumi; Shirotori, Akihide; Nozawa, Toshihisa; Matsuoka, Takaaki

    2012-05-01

    A robust fluorocarbon film was successfully deposited on a substrate at a temperature above 400 °C by the new microwave plasma-enhanced chemical vapor deposition (MWPE-CVD) method using the linear C5F8 precursor instead of a conventional cyclic C5F8 one. The fluorocarbon performed keeping the dielectric constant low as a value of 2.25 by controlling the molecular structure forming cross-linked poly(tetrafluoroethylene) (PTFE) chains with configurational carbon atoms. The novel fluorocarbon demonstrates less fluorine degassing at an elevated temperature, with high mechanical strength and without degradation of adhesion of the fluorocarbon film to SiCN and SiOx stacked films after thermal stress at 400 °C and 1 atm N2 for 1 h. Consequently, this robust fluorocarbon film is considered a promising candidate for general porous silicon materials with applications to practical integration processes as an interlayer dielectric.

  4. 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.

  5. Integration Process Development for Improved Compatibility with Organic Non-Porous Ultralow-k Dielectric Fluorocarbon on Advanced Cu Interconnects

    NASA Astrophysics Data System (ADS)

    Gu, Xun; Tomita, Yugo; Nemoto, Takenao; Miyatani, Kotaro; Saito, Akane; Kobayashi, Yasuo; Teramoto, Akinobu; Kuroda, Rihito; Kuroki, Shin-Ichiro; Kawase, Kazumasa; Nozawa, Toshihisa; Matsuoka, Takaaki; Sugawa, Shigetoshi; Ohmi, Tadahiro

    2012-05-01

    Integration of an organic non-porous ultralow-k dielectric, fluorocarbon (k= 2.2), into advanced Cu interconnects was demonstrated. The challenges of process-induced damage, such as delamination and variances of both the structure and electrical properties of the fluorocarbon during fabrication, were investigated on Cu/fluorocarbon damascene interconnects. A titanium-based barrier layer, instead of a tantalum-based barrier layer, was used to avoid delamination between Cu and fluorocarbon in Cu/fluorocarbon interconnects. A moisture-hermetic dielectric protective layer was also effective to avoid damage induced by wet chemical cleaning. On the other hand, a post-etching nitrogen plasma treatment to form a stable protective layer on the surface of the fluorocarbon was proposed for the practical minimization of damage introduction to fluorocarbon in the following damascene process, such as post-etching cleaning.

  6. 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.

  7. 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.

  8. 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.

  9. Fluorocarbon Fiber-Optic Raman Probe for Non-Invasive Raman Spectroscopy

    PubMed Central

    OKAGBARE, PAUL I.; MORRIS, MICHAEL D.

    2012-01-01

    We report the development of a novel fiber-optic Raman probe using a graded index fluorocarbon optical fiber. The fluorocarbon fiber has a simple Raman spectrum, a low fluorescence background, and generates a Raman signal that in turbid media serves as an intense reference Raman signal that corrects for albedo. The intensity of the reference signal can easily be varied as needed by scaling the length of the excitation fiber. Additionally, the fluorocarbon probe eliminates the broad silica Raman bands generated in conventional silica-core fiber without the need for filters. PMID:22732546

  10. 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.

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

    SciTech Connect

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

    2016-01-15

    With increasing demands on device patterning to achieve smaller critical dimensions and pitches for the 5 nm node and beyond, the need for atomic layer etching (ALE) is steadily increasing. In this work, 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.

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

    DOE PAGES

    Metzler, Dominik; Uppiredi, Kishore; Bruce, Robert L.; ...

    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

  13. 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.

  14. 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.

  15. Adhesion of metals to spin-coated fluorocarbon polymer films

    NASA Astrophysics Data System (ADS)

    Kim, Yong-Kil; Chang, Chin-An; Schrott, A. G.

    1990-01-01

    Adhesion between metals and fluorocarbon polymer films has been studied for Cu, Cr, Ti, Al, and Au on polytetrafluoroethylene (PTFE) and tetrafluoroethylene-hexafluoropropylene copolymer (FEP) films. Polymer films were applied on the Cr/SiO2 /Si substrate by spinning the aqueous dispersions of the polymer resin particles, followed by thermal curing. Strips of different metals were deposited on the polymers, and adhesion was measured at 90° peel test. The peel strengths were invariably higher for the metals on FEP than those of the corresponding metals on PTFE. Among the metals, Ti showed the highest peel strength for both polymers, followed by Cr and Al, with Cu and Au being the lowest. The peel strengths of Ti, Cr, and Cu on FEP are 85, 45, and 12 g/mm, respectively, and the corresponding ones on PTFE are 23, 5, and 2 g/mm, respectively. X-ray photoelectron spectroscopic analysis shows that the metal-polymer bonding involves the metal-carbon interactions. The strongest interaction is observed for Ti with the polymers, forming Ti carbidelike bonds. Cr also shows strong interaction with the two polymers, but to a lesser degree compared with Ti. Only a weak bonding is shown for Cu. The difference in peel strengths among the metals shows a correlation with the difference in electronegativities between the metals and carbon. Little contribution to the observed peel strengths is seen from the surface morphological analysis of the untreated polymers.

  16. 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.

  17. Biomimetic fluorocarbon surfactant polymers reduce platelet adhesion on PTFE/ePTFE surfaces.

    PubMed

    Wang, Shuwu; Gupta, Anirban Sen; Sagnella, Sharon; Barendt, Pamela M; Kottke-Marchant, Kandice; Marchant, Roger E

    2009-01-01

    We describe a series of fluorocarbon surfactant polymers designed as surface-modifying agents for improving the thrombogenicity of ePTFE vascular graft materials by the reduction of platelet adhesion. The surfactant polymers consist of a poly(vinyl amine) backbone with pendent dextran and perfluoroundecanoyl branches. Surface modification is accomplished by a simple dip-coating process in which surfactant polymers undergo spontaneous surface-induced adsorption and assembly on PTFE/ePTFE surface. The adhesion stability of the surfactant polymer on PTFE was examined under dynamic shear conditions in PBS and human whole blood with a rotating disk system. Fluorocarbon surfactant polymer coatings with three different dextran to perfluorocarbon ratios (1:0.5, 1:1 and 1:2) were compared in the context of platelet adhesion on PTFE/ePTFE surface under dynamic flow conditions. Suppression of platelet adhesion was achieved for all three coated surfaces over the shear-stress range of 0-75 dyn/cm2 in platelet-rich plasma (PRP) or human whole blood. The effectiveness depended on the surfactant polymer composition such that platelet adhesion on coated surfaces decreased significantly with increasing fluorocarbon branch density at 0 dyn/cm2. Our results suggest that fluorocarbon surfactant polymers can effectively suppress platelet adhesion and demonstrate the potential application of the fluorocarbon surfactant polymers as non-thrombogenic coatings for ePTFE vascular grafts.

  18. Biomimetic Fluorocarbon Surfactant Polymers Reduce Platelet Adhesion on PTFE/ePTFE Surfaces

    PubMed Central

    Wang, Shuwu; Gupta, Anirban Sen; Sagnella, Sharon; Barendt, Pamela M.; Kottke-Marchant, Kandice; Marchant, Roger E.

    2010-01-01

    We describe a series of fluorocarbon surfactant polymers designed as surface-modifying agents for improving the thrombogenicity of ePTFE vascular graft materials by the reduction of platelet adhesion. The surfactant polymers consist of a poly(vinyl amine) backbone with pendent dextran and perfluoroundecanoyl branches. Surface modification is accomplished by a simple dip-coating process in which surfactant polymers undergo spontaneous surface-induced adsorption and assembly on PTFE/ePTFE surface. The adhesion stability of the surfactant polymer on PTFE was examined under dynamic shear conditions in PBS and human whole blood with a rotating disk system. Fluorocarbon surfactant polymer coatings with three different dextran to perfluorocarbon ratios (1:0.5, 1:1 and 1:2) were compared in the context of platelet adhesion on PTFE/ePTFE surface under dynamic flow conditions. Suppression of platelet adhesion was achieved for all three coated surfaces over the shear-stress range of 0–75 dyn/cm2 in platelet-rich plasma (PRP) or human whole blood. The effectiveness depended on the surfactant polymer composition such that platelet adhesion on coated surfaces decreased significantly with increasing fluorocarbon branch density at 0 dyn/cm2. Our results suggest that fluorocarbon surfactant polymers can effectively suppress platelet adhesion and demonstrate the potential application of the fluorocarbon surfactant polymers as non-thrombogenic coatings for ePTFE vascular grafts. PMID:19323880

  19. 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.

  20. 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.

  1. Novel fluoro-carbon functional monomer for dental bonding.

    PubMed

    Yoshihara, K; Yoshida, Y; Hayakawa, S; Nagaoka, N; Kamenoue, S; Okihara, T; Ogawa, T; Nakamura, M; Osaka, A; Van Meerbeek, B

    2014-02-01

    Among several functional monomers, 10-methacryloxydecyl dihydrogen phosphate (10-MDP) bonded most effectively to hydroxyapatite (HAp). However, more hydrolysis-resistant functional monomers are needed to improve bond durability. Here, we investigated the adhesive potential of the novel fluoro-carbon functional monomer 6-methacryloxy-2,2,3,3,4,4,5,5-octafluorohexyl dihydrogen phosphate (MF8P; Kuraray Noritake Dental Inc., Tokyo, Japan) by studying its molecular interaction with powder HAp using solid-state nuclear magnetic resonance ((1)H MAS NMR) and with dentin using x-ray diffraction (XRD) and by characterizing its interface ultrastructure at dentin using transmission electron microscopy (TEM). We further determined the dissolution rate of the MF8P_Ca salt, the hydrophobicity of MF8P, and the bond strength of an experimental MF8P-based adhesive to dentin. NMR confirmed chemical adsorption of MF8P onto HAp. XRD and TEM revealed MF8P_Ca salt formation and nano-layering at dentin. The MF8P_Ca salt was as stable as that of 10-MDP; MF8P was as hydrophobic as 10-MDP; a significantly higher bond strength was recorded for MF8P than for 10-MDP. In conclusion, MF8P chemically bonded to HAp. Despite its shorter size, MF8P possesses characteristics similar to those of 10-MDP, most likely to be associated with the strong chemical bond between fluorine and carbon. Since favorable bond strength to dentin was recorded, MF8P can be considered a good candidate functional monomer for bonding.

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

    SciTech Connect

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

    2015-08-21

    Rate coefficients and product branching fractions for electron attachment and for reaction with Ar{sup +} are measured over the temperature range 300–585 K for three monohydrogenated fluorocarbon (HFC) radicals (CF{sub 3}CHF, CHF{sub 2}CF{sub 2}, and CF{sub 3}CHFCF{sub 2}), as well as their five closed-shell precursors (1-HC{sub 2}F{sub 4}I, 2-HC{sub 2}F{sub 4}I, 2-HC{sub 2}F{sub 4}Br, 1-HC{sub 3}F{sub 6}I, 2-HC{sub 3}F{sub 6}Br). 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 C{sub n}F{sub m−1}{sup −} anions, with only a minor branching to F{sup −} 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-HC{sub 2}F{sub 4}Br, 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{sup +} proceeds at or near the calculated collisional rate coefficient in all cases, yielding a wide variety of product ions.

  3. Hyperbranched hydrocarbon surfactants give fluorocarbon-like low surface energies.

    PubMed

    Sagisaka, Masanobu; Narumi, Tsuyoshi; Niwase, Misaki; Narita, Shioki; Ohata, Atsushi; James, Craig; Yoshizawa, Atsushi; Taffin de Givenchy, Elisabeth; Guittard, Frédéric; Alexander, Shirin; Eastoe, Julian

    2014-06-03

    Two series of Aerosol-OT-analogue surfactants (sulfosuccinate-type di-BCnSS and sulfoglutarate-type di-BCnSG) with hyperbranched alkyl double tails (so-called "hedgehog" groups, carbon number n = 6, 9, 12, and 18) have been synthesized and shown to demonstrate interfacial properties comparable to those seen for related fluorocarbon (FC) systems. Critical micelle concentration (CMC), surface tension at the CMC (γCMC), and minimum area per molecule (Amin) were obtained from surface tension measurements of aqueous surfactant solutions. The results were examined for relationships between the structure of the hedgehog group and packing density at the interface. To evaluate A and B values in the Klevens equation for these hedgehog surfactants, log(CMC) was plotted as a function of the total carbon number in the surfactant double tail. A linear relationship was observed, producing B values of 0.20-0.25 for di-BCnSS and di-BCnSG, compared to a value of 0.31 for standard double-straight-tail sulfosuccinate surfactants. The lower B values of these hedgehog surfactants highlight their lower hydrophobicity compared to double-straight-tail surfactants. To clarify how hydrocarbon density in the surfactant-tail layer (ρ(layer)) affects γCMC, the ρ(layer) of each double-tail surfactant was calculated and the relationship between γCMC and ρ(layer) examined. As expected for the design of low surface energy surfactant layers, ρ(layer) was identified as an important property for controlling γCMC with higher ρ(layer), leading to a lower γCMC. Interestingly, surfactants with BC9 and BC12 tails achieved much lower γCMC, even at low ρ(layer) values of <0.55 g cm(-3). The lowest surface energy surfactant studied here was di-BC6SS, which had a γCMC of only 23.8 mN m(-1). Such a low γCMC is comparable to those obtained with short FC-tail surfactants (e.g., 22.0 mN m(-1) for the sulfosuccinate-type FC-surfactant with R = F(CF2)6CH2CH2-).

  4. 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.

  5. Total electron scattering cross section of Fluorocarbons at intermediate electron energies

    NASA Astrophysics Data System (ADS)

    Palihawadana, Prasanga; Villela, Gilberto; Ariyasinghe, Wickramasinghe

    2008-10-01

    Total electron scattering cross sections (TCS) of Tetrafluoromethane (CF4), Trifluoromethane (CHF3), Hexafluoroethane (C2F6) and Octafluorocyclobutane (C4F8) have been measured using the linear transmission technique for impact energies 0.10 -- 4.00 keV. These TCS are compared to existing experimental and theoretical TCS in the literature. Based on the present measurements, an empirical formula is developed to predict the TCS of fluorocarbons as a function of incident electron energy.

  6. Wettability of polymeric solids by ternary mixtures composed of hydrocarbon and fluorocarbon nonionic surfactants.

    PubMed

    Szymczyk, Katarzyna

    2011-11-01

    Contact angle (θ) measurements on poly(tetrafluoroethylene) (PTFE) and polymethyl methacrylate (PMMA) surface were carried out for the systems containing ternary mixtures of surfactants composed of: p-(1,1,3,3-tetramethylbutyl)phenoxypoly(ethylene glycols), Triton X-100 (TX100), Triton X-165 (TX165) and Triton X-114 (TX114), and fluorocarbon surfactants, Zonyl FSN100 (FSN100) and Zonyl FSO100 (FSO100). The aqueous solutions of ternary surfactant mixtures were prepared by adding TX114, FSN100 or FSO100 to binary mixtures of TX100+TX165, where the synergistic effect in the reduction of the surface tension of water (γ(LV)) was determined. From the obtained contact angle values, the relationships between cosθ, the adhesion tension and surface tension of solutions, cosθ and the reciprocal of the surface tension were determined. On the basis of these relationships, the correlation between the critical surface tension of PTFE and PMMA wetting and the surface tension of these polymers as well as the work of adhesion of aqueous solutions of ternary surfactant mixtures to PTFE and PMMA surface were discussed. The critical surface tension of PTFE and PMMA wetting, γ(C), determined from the contact angle measurements of aqueous solutions of surfactants including FSN100 or FSO100 was also discussed in the light of the surface tension changes of PTFE and PMMA under the influence of film formation by fluorocarbon surfactants on the surface of these polymers. The γ(C) values of the studied polymeric solids were found to be different for the mixtures composed of hydrocarbon surfactants in comparison with those of hydrocarbon and fluorocarbon surfactants. In the solutions containing fluorocarbon surfactants, the γ(C) values were different taking into account the contact angle in the range of FSN100 and FSO100 concentration corresponding to their unsaturated monolayer at water-air interface or to that saturated.

  7. The Effect of Fluorocarbon Surfactant Additives on the Effective Viscosity of Acetone Solutions of Cellulose Diacetate,

    DTIC Science & Technology

    2014-09-26

    34 FOREIGN TECHNOLOGY DIVISION i00 Lfl .. THE EFFECT OF FLUOROCARBON SURFACTANT ADDITIVES ON THE EFFECTIVE VISCOSITY OF ACETONE SOLUTIONS OF CELLULOSE...ADDITIVES ON TH~ .. t- ’_ ition EFFECTIVE VISCOSITY OF ACETONE SOLUTIONS OF CELLULOSE DIACETATE D~rbt~l By: L.A. Shits, N. Yu. Kal’nova Codesuton English...VISCOSITY OF ACETONE SOLUTIONS OF CELLULOSE DIACETATE L. A. Shits, N. Yu. Kal’nova (Institute of Physical Chemistry of the AS USSR, Moscow) ! - The

  8. 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.

  9. 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 80-85°C, 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.

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

    PubMed

    Zhao, Tao; Zheng, Junzhi; Sun, Gang

    2012-06-05

    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.

  11. Investigation on anti-corrosion property of nano-TiO2 fluoro-carbon coatings

    NASA Astrophysics Data System (ADS)

    Qi, Yu-hong; Zhang, Zhan-ping; Wang, Li-li; Du, Xue-peng

    2009-07-01

    To meet the need of long-term anticorrosive protection of steel, a heavy-duty anticorrosive coating systems was developed with Fluorocarbon top paint which was modified by nano-TiO2. The corrosive characteristics of low carbon steel coated with the system were investigated in seawater by the exposition tests and Electrochemical Impedance Spectroscopy (EIS). The results show that the protective system with fluorocarbon top coating modified by nano-TiO2 has much better endurance than the reference system with fluorocarbon top coating not modified by nano-TiO2. There isn't any rusting and blistering on the surface of former coating, the coating system remains in "GOOD" condition. But some rusting and blistering were found on the surface of reference coating. EIS results indicated that the impedance of the nano-coating system decreases much less than that of the reference one. The nano-coating system is hopeful to meet the need of new coatings standard and to provide a target useful coating life of 15 years for ship's ballast.

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

    PubMed

    Szymczyk, Katarzyna; González-Martín, Maria Luisa; Bruque, Jose Morales; Jańczuk, Bronisław

    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.

  13. 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.

  14. 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.

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

    SciTech Connect

    Chen, Teng-Hao; Popov, Ilya; Kaveevivitchai, Watchareeya; Chuang, Yu-Chun; Chen, Yu-Sheng; Jacobson, Allan J.; Miljani,; #263; Ognjen, Š.

    2016-02-08

    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 m2g-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.

  16. 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.

  17. 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.

  18. 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.

  19. Effect of fluorocarbon-for-blood exchange on regional blood flow in rats

    SciTech Connect

    Lee, P.A.; Sylvia, A.L.; Piantadosi, C.A. )

    1988-04-01

    Cerebrocirculatory responses to total perfluorocarbon (FC-43)-for-blood replacement were studied in anesthetized, ventilated rats breathing 100% O{sub 2}. Changes in total and regional cerebral blood flow (CBF) were measured using the radiolabeled-microsphere technique. The data were compared with two control groups of hemoglobin-circulated animals; one group was exposed to arterial hypoxia and the other to isovolemic hemodilution with Krebs-Henseleit-albumin (KHA) solution. Exchange transfusion with FC-43 doubled total and regional CBF, causing preferential flow increases to the cortex and cerebellum. Estimated cerebrovascular resistance fell to 50% of the preexchange value. Both hemodilution and hypoxia control experiments produced CBF responses similar to those obtained in FC-43 animals. Although calculated arterial O{sub 2} contents in all three groups of animals were similar, blood viscosity was normal in hypoxic rats and reduced in KHA and FC-43 animals. Since arterial and cerebrovenous Po{sub 2}s were both high in fluorocarbon-circulated rats, over results suggest that decreased O{sub 2} content and perhaps lower viscosity of the circulating fluorocarbon were responsible for increases in CBF required to maintain sufficient delivery of O{sub 2} to the brain.

  20. Miscibility of Hydrocarbon and Fluorocarbon Surfactants in Adsorbed Film and Micelle.

    PubMed

    Villeneuve, Masumi; Nomura, Teruko; Matsuki, Hitoshi; Kaneshina, Shoji; Aratono, Makoto

    2001-02-01

    We investigated the miscibility of nonionic hydrocarbon and fluorocarbon surfactants in the adsorbed film and the micelle by surface tension measurements of the aqueous solution. The combination of tetraethyleneglycol monodecyl ether (C10E4) and tetraethyleneglycol mono-1,1,7-trihydrododecafluoroheptyl ether (FC7E4) was chosen because they have the same hydrophilic groups and about the same surface activity. The extent of nonideal mixing was estimated quantitatively in terms of the excess Gibbs energy in the adsorbed film g(H,E) and that in the micelle g(M,E). The excess area per adsorbed molecule, A(H,E), was also evaluated and discussed. The ionic hydrocarbon and fluorocarbon mixed surfactant systems, lithium dodecyl sulfate (LiDS)/lithium perfluorooctane sulfonate (LiFOS) and lithium tetradecyl sulfate (LiTS)/LiFOS systems are also investigated from the standpoint of excess Gibbs energy and excess area. It is also clearly shown that the regular solution approach does not fit in the systems that contain ionic species. Copyright 2001 Academic Press.

  1. Selectivity control in micellar electrokinetic chromatography of small peptides using mixed fluorocarbon-hydrocarbon anionic surfactants.

    PubMed

    Ye, B; Hadjmohammadi, M; Khaledi, M G

    1995-02-10

    Electrophoretic mobilities and capacity factors for a group of Trp-containing small peptides were determined by micellar electrokinetic chromatography (MEKC) using mixtures of a fluorocarbon anionic surfactant, lithium perfluorooctane sulfonate, and a hydrocarbon anionic surfactant, lithium dodecyl sulfate. Upon mixing these two surfactants, which have different microenvironments and interactive characteristics, greater control over migration of solutes is achieved. The changes in the composition of mixed micelles such as the mole fraction of the surfactants result in different solute-micelle binding as well as migration times of the micelles (tmc). Consequently, capacity factor, selectivity and elution window (tmc/t0) change with the composition of the mixed micellar system. Another characteristic of the mixtures of fluorocarbon-hydrocarbon surfactants is the possibility of forming two different types of micelles which offers an additional partitioning process for each solute in the MEKC system. Such a unique phenomenon offers a higher degree of selectivity control. This mixed MEKC system is quite effective for the separation of small peptides. It provides an alternative to the free-solution capillary zone electrophoresis system for the separation of charged solutes with nearly identical electrophoretic mobility.

  2. Fluorocarbon and hydrocarbon N-heterocyclic (C5-C7) imidazole-based liquid crystals.

    PubMed

    Chen, Hongren; Hong, Fengying; Shao, Guang; Hang, Deyu; Zhao, Lei; Zeng, Zhuo

    2014-12-01

    By using three synthetic protocols, a series of fluorocarbon and hydrocarbon N-heterocyclic imidazole-based liquid crystals (LCs) and related imidazolium-based ionic liquid crystals (ILCs) have been prepared. The ring size of the N-heterocycle and the length of the N-terminal chain (on the imidazolium unit in the ILCs) were modified, and the influence of these structural parameters on liquid-crystal phases was investigated by means of polarizing optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). These new ILCs exhibit a disordered smectic phase (SmA), good thermal stabilities, a broad smectic phase range, a high dipole moment, relatively low melting points, but high clearing points and strong emission fluorescence relative to imidazole-based LCs. These encouraging results have led us to believe these fluorocarbon and hydrocarbon N-heterocyclic imidazole-based LCs and related imidazolium-based ILCs could be used as new liquid-crystalline materials.

  3. 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

    2016-01-13

    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.

  4. 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

  5. Application of quantum cascade laser absorption spectroscopy to studies of fluorocarbon molecules

    NASA Astrophysics Data System (ADS)

    Welzel, S.; Stepanov, S.; Meichsner, J.; Röpcke, J.

    2009-03-01

    The recent advent of quantum cascade lasers (QCLs) enables room-temperature mid-infrared spectrometer operation which is particularly favourable for industrial process monitoring and control, i.e. the detection of transient and stable molecular species. Conversely, fluorocarbon containing radio-frequency discharges are of special interest for plasma etching and deposition as well as for fundamental studies on gas phase and plasma surface reactions. The application of QCL absorption spectroscopy to such low pressure plasmas is typically hampered by non-linear effects connected with the pulsed mode of the lasers. Nevertheless, adequate calibration can eliminate such effects, especially in the case of complex spectra where single line parameters are not available. In order to facilitate measurements in fluorocarbon plasmas, studies on complex spectra of CF4 and C3F8 at 7.86 μm (1269 - 1275 cm-1) under low pressure conditions have been performed. The intra-pulse mode, i.e. pulses of up to 300 ns, was applied yielding highly resolved spectral scans of ~ 1 cm-1 coverage. Effective absorption cross sections were determined and their temperature dependence was studied in the relevant range up to 400 K and found to be non-negligible.

  6. Plasma polymerization and deposition of linear, cyclic and aromatic fluorocarbons on (100)-oriented single crystal silicon substrates

    NASA Astrophysics Data System (ADS)

    Yang, G. H.; Oh, S. W.; Kang, E. T.; Neoh, K. G.

    2002-11-01

    Fluoropolymer films were deposited on the Ar plasma-pretreated Si(100) surfaces by plasma polymerization of perfluorohexane (PFH, a linear fluorocarbon), perfluoro(methylcyclohexane) (MCH, a cyclic fluorocarbon), and hexafluorobenzene (HFB, an aromatic fluorocarbon) under different glow discharge conditions. The effects of the radio-frequency plasma power on the chemical composition and structure of the plasma-polymerized fluoropolymer films were studied by x-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, time-of-flight secondary ion mass spectrometry, and water contact angle measurements. The changes in structure and composition of the three types of the plasma-deposited films from those of the respective fluorocarbons were compared. Under similar glow discharge conditions: (i) the extent of defluorination was highest for the PFH polymer, (ii) the deposition rate was highest for the HFB polymer, (iii) the cyclic structure of MCH was less well preserved than the aromatic structure of HFB, (iv) aliphatic structures appeared in the plasma-deposited MCH polymer, and (v) the plasma-polymerized HFB has the highest thermal stability due to the preservation of the aromatic rings. The adhesive tape peel test results revealed that the plasma-polymerized and deposited fluoropolymer layers were strongly bonded to the Ar plasma-pretreated Si(100) surfaces.

  7. Chemical modification of the poly(vinylidene fluoride-trifluoroethylene) copolymer surface through fluorocarbon ion beam deposition

    SciTech Connect

    Hsu, W.-D.; Jang, Inkook; Sinnott, Susan B.

    2007-07-15

    Classical molecular dynamics simulations are used to study the effects of continuous fluorocarbon ion beam deposition on a poly(vinylidene fluoride-trifluoroethylene) [P(VDF-trFE)] surface, a polymer with electromechanical properties. Fluorocarbon plasma processing is widely used to chemically modify surfaces and deposit thin films. It is well accepted that polyatomic ions and neutrals within low-energy plasmas have a significant effect on the surface chemistry induced by the plasma. The deposition of mass selected fluorocarbon ions is useful to isolate the effects specific to polyatomic ions. Here, the differences in the chemical interactions of C{sub 3}F{sub 5}{sup +} and CF{sub 3}{sup +} ions with the P(VDF-trFE) surface are examined. The incident energy of the ions in both beams is 50 eV. The CF{sub 3}{sup +} ions are predicted to be more effective at fluorinating the P(VDF-trFE) surface than C{sub 3}F{sub 5}{sup +} ions. At the same time, the C{sub 3}F{sub 5}{sup +} ions are predicted to be more effective at growing fluorocarbon thin films. The simulations also reveal how the deposition process might ultimately modify the electromechanical properties of this polymer surface.

  8. Measurement of the absolute CF2 concentration in a dielectric barrier discharge running in argon/fluorocarbon mixtures

    NASA Astrophysics Data System (ADS)

    Vinogradov, I. P.; Dinkelmann, A.; Lunk, A.

    2004-11-01

    The role of different CFx-radicals in plasma polymerization in fluorocarbon mixtures has not been determined yet. Therefore spectroscopic investigations of dielectric barrier discharges (DBDs) in argon/fluorocarbon mixtures at atmospheric pressure were conducted with the focus on measurement of the concentration of CFx-radicals. The following diagnostic procedures were applied: FTIR absorption spectroscopy to diagnose stable compounds in the discharge, optical emission spectroscopy of the DBD in the UV and visible range and measurement of the CF2 concentration by UV absorption spectroscopy. The DBD was running in argon with the following admixtures: CF4, C2F6, C2H2F4, C3F8, C3HF7, c-C4F8. The relative concentration of the CF3-radical and the absolute concentration of CF2 in Ar/fluorocarbon mixtures were measured by emission spectroscopy and by absorption and emission spectroscopy, respectively. Emission and absorption spectroscopy were performed simultaneously in combination with electrical measurements of the discharge characteristics. The influence of small amounts of hydrogen or oxygen added to the argon/fluorocarbon mixtures was investigated.

  9. 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.

  10. 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.

  11. Development of molecular based optical techniques for thermometry and velocimetry for fluorocarbon media

    NASA Astrophysics Data System (ADS)

    Pouya, Shahram; Blanchard, Gary; Koochesfahani, Manoochehr

    2016-11-01

    Fluorocarbon solvents are very stable inert fluids with unique physical properties that make them attractive compounds as refrigerant and several medical applications such as contrast enhanced ultrasound imaging. Since they do not mix with typical organic solvents or water, most luminescent (fluorescent or phosphorescent) probes cannot be used as tracers for optical diagnostic techniques. Perfluoropentane, a compound from this family, is used as a simulant fluid by NASA for two-phase heat transfer/mixing experiments under micro-gravity condition due to its low boiling temperature. Here we study the feasibility of employing non-intrusive optical methods for measurements of temperature and/or velocity within Perfluoropentane as the working fluid. Preliminary results of temperature and velocity measurement using Laser Induced Fluorescence and Molecular Tagging Velocimetry are presented. This work was supported by NASA Grant Number NNX16AD52A.

  12. 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.

  13. 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.

  14. Preparation of transparent fluorocarbon/TiO2-SiO2 composite coating with improved self-cleaning performance and anti-aging property

    NASA Astrophysics Data System (ADS)

    Zhou, Jianping; Tan, Zhongyuan; Liu, Zhilei; Jing, Mengmeng; Liu, Wenjie; Fu, Wanli

    2017-02-01

    This work reports a facile method to fabricate transparent self-cleaning fluorocarbon coatings filled by semicrystalline colloidal particles of TiO2-SiO2 composite oxide presenting a particle size ranging from 6 to 10 nm. Anatase-TiO2 crystallites were successfully obtained after microwave heating treatment of the TiO2-SiO2 colloidal particles as confirmed by XRD, TEM and FTIR measurements. The fluorocarbon/TiO2-SiO2 composite coatings exhibited a superior hydrophilicity and an improved photocatalytic activity in contrast to the TiO2-filled coatings. In particular, a water contact angle (WCA) value of 4.5° and a decolorization ratio relative to methyl orange as high as 96.0% were achieved for the composite coatings containing 1.5 wt% of TiO2-SiO2 colloidal particles. The results of the anti-soiling experiments indicated that the fluorocarbon/TiO2-SiO2 composite coatings exhibited a prominent self-cleaning performance, while the accelerated aging experiments revealed that the fluorocarbon/TiO2-SiO2 composite coatings were highly stable toward UV irradiation when compared to the TiO2-filled fluorocarbon coatings. These findings indicated that the fluorocarbon/TiO2-SiO2 composite coatings could be a very attractive solution for many practical areas, especially for outdoor applications.

  15. 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-μm diameter with a lateral dispensing accuracy of 89 μm. 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 μm. 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

  16. 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.

  17. Surface modification of silicon-containing fluorocarbon films prepared by plasma-enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Jin, Yoonyoung; Desta, Yohannes; Goettert, Jost; Lee, G. S.; Ajmera, P. K.

    2005-07-01

    Surface modification of silicon-containing fluorocarbon (SiCF) films achieved by wet chemical treatments and through x-ray irradiation is examined. The SiCF films were prepared by plasma-enhanced chemical vapor deposition, using gas precursors of tetrafluoromethane and disilane. As-deposited SiCF film composition was analyzed by x-ray photoelectron spectroscopy. Surface modification of SiCF films utilizing n-lithiodiaminoethane wet chemical treatment is discussed. Sessile water-drop contact angle changed from 95°+/-2° before treatment to 32°+/-2° after treatment, indicating a change in the film surface characteristics from hydrophobic to hydrophilic. For x-ray irradiation on the SiCF film with a dose of 27.4 kJ/cm3, the contact angle of the sessile water drop changed from 95°+/-2° before radiation to 39°+/-3° after x-ray exposure. The effect of x-ray exposure on chemical bond structure of SiCF films is studied using Fourier transform infrared measurements. Electroless Cu deposition was performed to test the applicability of the surface modified films. The x-ray irradiation method offers a unique advantage in making possible surface modification in a localized area of high-aspect-ratio microstructures. Fabrication of a Ti-membrane x-ray mask is introduced here for selective surface modification using x-ray irradiation.

  18. 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.

  19. Static light scattering study of fluorocarbon-modified ampholytic acrylamide ionomers

    SciTech Connect

    Watterson, A.C.; Haralabakopoulos, A.; Salamone, J.C.

    1993-12-31

    A series of water-soluble acrylamide ionomers containing small amounts of ampholytic and hydrophobic sites were investigated in dilute aqueous and aqueous salt solutions via static light scattering methods. Elemental analysis verified the ampholytic nature of the polymers while the ion/hydrophobe content was found to be much lower than what was supplied in the feed. Both the molecular weight and radius of gyration exhibited increases with increasing comonomer content to maximum values at 2.5-3.0 mole%. Mw and Rg increased further in 1 M aqueous NaCl and dropped to previous levels in 3 M NaCl. The radius of gyration exhibited sizable increased at 45 and 70{degrees}C in aqueous solution, less so in 1 M NaCl. Dilute aqueous salt expanded the molecules through shielding of the ionic sites, while concentrated aqueous salt increased hydrophobic aggregation decreasing the size of the polymers. At higher temperatures salt ions failed to reach the ionic sites and fluorocarbon aggregation is thought to be responsible for the low radii of gyration.

  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. 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.

  2. Fluidization of a dipalmitoyl phosphatidylcholine monolayer by fluorocarbon gases: potential use in lung surfactant therapy.

    PubMed

    Gerber, Frédéric; Krafft, Marie Pierre; Vandamme, Thierry F; Goldmann, Michel; Fontaine, Philippe

    2006-05-01

    Fluorocarbon gases (gFCs) were found to inhibit the liquid-expanded (LE)/liquid-condensed (LC) phase transition of dipalmitoyl phosphatidylcholine (DPPC) Langmuir monolayers. The formation of domains of an LC phase, which typically occurs in the LE/LC coexistence region upon compression of DPPC, is prevented when the atmosphere above the DPPC monolayer is saturated with a gFC. When contacted with gFC, the DPPC monolayer remains in the LE phase for surface pressures lower than 38 mN m(-1), as assessed by compression isotherms and fluorescence microscopy (FM). Moreover, gFCs can induce the dissolution of preexisting LC phase domains and facilitate the respreading of the DPPC molecules on the water surface, as shown by FM and grazing incidence x-ray diffraction. gFCs have thus a highly effective fluidizing effect on the DPPC monolayer. This gFC-induced fluidizing effect was compared with the fluidizing effect brought about by a mixture of unsaturated lipids and proteins, namely the two commercially available lung surfactant substitutes, Curosurf and Survanta, which are derived from porcine and bovine lung extracts, respectively. The candidate FCs were chosen among those already investigated for biomedical applications, and in particular for intravascular oxygen transport, i.e., perfluorooctyl bromide, perfluorooctylethane, bis(perfluorobutyl)ethene, perfluorodecalin, and perfluorooctane. The fluidizing effect is most effective with the linear FCs. This study suggests that FCs, whose biocompatibility is well documented, may be useful in lung surfactant substitute compositions.

  3. Interactions in water of alkyl and perfluoroalkyl surfactants with fluorocarbon- and hydrocarbon-modified poly(N-isopropylacrylamides).

    PubMed

    Kujawa, Piotr; Raju, B Bangar; Winnik, Francoise M

    2005-10-25

    Fluorescence spectroscopy and isothermal titration calorimetry (ITC) have been used to study the interactions in water at 25 degrees C of two anionic surfactants--sodium dodecyl sulfate (SDS) and sodium perfluorononanoate (SPFN)--with various pyrene-labeled hydrophobically modified poly(N-isopropylacrylamides) (HM-PNIPAM) grafted at random with small amounts of fluorocarbon chains (1H,1H-perfluorooctyl, CH2C7F15); (PNIPAM-F), or (n-octadecyl, C18H37) (PNIPAM-HPy) or both (PNIPAM-F/HPy). In aqueous solution, the copolymers form micellar structures consisting of a loose corona of hydrated poly(N-isopropylacrylamide) chains and a hydrophobic core rich in hydrocarbon or fluorocarbon groups. From fluorescence studies based on changes in the ratio of pyrene excimer to monomer emission intensity, it has been established (1) that mixed SDS/C18H37 clusters form along the polymer chain upon addition of SDS to either PNIPAM-HPy or PNIPAM-F/HPy and (2) that SPFN does not interact with the hydrocarbon-rich microdomains of the polymeric micelles. The conclusions were corroborated by ITC experiments, which yield the overall enthalpy change associated with polymer/surfactant interactions. They provided strong evidence (1) that SDS molecules adsorb along the PNIPAM main chain but do not mix with the fluorocarbon-rich microdomains of PNIPAM-F or PNIPAM-F/HPy and (2) that SPFN associates with the perfluorocarbon substituents of PNIPAM-F and PNIPAM-F/HPy but has a poor affinity for the polymer chain.

  4. 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.

  5. 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.

  6. Microbubbles with a Self-Assembled Poloxamer Shell and a Fluorocarbon Inner Gas.

    PubMed

    Ando, Yu; Tabata, Hiraku; Sanchez, Michaël; Cagna, Alain; Koyama, Daisuke; Krafft, Marie Pierre

    2016-11-29

    The numerous applications of microbubbles in food science and medicine call for a better understanding and control of the effects of the properties of their shells on their stability and ability to resonate at chosen frequencies when submitted to an ultrasound field. We have investigated both millimetric and micrometric bubbles stabilized by an amphiphilic block copolymer, Poloxamer 188 (e.g., Pluronic F-68). Although Pluronic F-68 is routinely being used as a dispersing and foaming agent to facilitate phospholipid-based microbubble preparation, it has never been studied as a shell component per se. First, we investigated the adsorption kinetics of Pluronic F-68 at the interface between water and air, or air saturated with vapors of perfluorohexane (F-hexane), using bubble profile tensiometry analysis. F-Hexane was found to strongly accelerate the adsorption of Pluronic F-68 (at low concentrations) and decrease the interfacial tension values at equilibrium (at all concentrations). We also found that relatively stable microbubbles could unexpectedly be prepared from Pluronic F-68 in the absence of any other surfactant, but only when F-hexane was present. These bubbles showed an only limited volume increase over ∼3 h, while a 10-fold increase in size occurred within 200 s in the absence of a fluorocarbon. Remarkably, their deflation rate decreased when the Pluronic F-68 concentration decreased, suggesting that bubbles with semidilute copolymer coverage are more stable than those more densely covered by copolymer brushes. Single-bubble experiments using laser Doppler vibratometry showed that, by contrast with other surfactant-coated microbubbles, the resonance radius of the Pluronic F-68-coated microbubbles was lower than that of naked microbubbles, meaning that they are less elastic. It was also found that the bubble's vibrational displacement amplitude decreased substantially when the microbubbles were covered with Pluronic F-68, an effect that was further

  7. 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.

  8. The effect of polar end of long-chain fluorocarbon oligomers in promoting the superamphiphobic property over multi-scale rough Al alloy surfaces

    NASA Astrophysics Data System (ADS)

    Saifaldeen, Zubayda S.; Khedir, Khedir R.; Camci, Merve T.; Ucar, Ahmet; Suzer, Sefik; Karabacak, Tansel

    2016-08-01

    Rough structures with re-entrant property and their subsequent surface energy reduction with long-chain fluorocarbon oligomers are both critical in developing superamphiphobic (SAP, i.e. both super hydrophobic and superoleophobic) surfaces. However, morphology of the low-surface energy layer on a rough re-entrant substrate can strongly depend on the fluorocarbon oligomers used. In this study, the effect of polar end of different kinds of long-chain fluorocarbon oligomers in promoting a self-assembled monolayer with close packed molecules and robust adhesion on multi-scale rough Al alloy surfaces was investigated. Hierarchical Al alloy surfaces with microgrooves and nanograss structures were developed by a simple combination of one-directional mechanical sanding and post treatment in boiling de-ionized water (DIW). Three types of long-chain fluorocarbon oligomers of 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane (PFDTS), 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane (PFDCS), and perfluorooctanoic acid (PFOA) were chemically vaporized onto these rough Al alloy surfaces. The PFDCS exhibited the lowest surface free energy of less than 10 mN/m. The contact angle and sliding angle measurements for water, ethylene glycol, and peanut oil verified the SAP property of hierarchical rough Al alloy surfaces treated with alkylsilane oligomers (PFDTS, PFDCS). However, the hierarchical surfaces treated with fluorocarbon oligomer with polar acidic tail (PFOA) showed highly amphiphobic properties but could not reach the threshold for SAP. Chemical stability of the hierarchical Al alloy surfaces treated with the fluorocarbon oligomers was tested under the harsh conditions of ultra-sonication in acetone and annealing at high temperature after different treatment times. Contact angle measurements revealed the robustness of the alkylsilane oligomers and deterioration of the PFOA coating particularly for low surface tension liquids. The robust adhesion and close-packing of the alkylsilane

  9. Synthesis of silane coupling agents containing fluorocarbon chain and applications to dentistry: plaque-controlling surface modifiers.

    PubMed

    Yoshino, N; Teranaka, T

    1997-01-01

    Silane coupling agents containing a fluorocarbon chain were prepared in high yields. It was found that silanes can be useful modifiers of the surfaces of glass, metals, and resin composites for dental use. The silane coupling agent CF3(CF2)9CH2CH2Si(OCH3)3 was the best modifier of these surfaces in terms of water and oil repellency. Colorants and experimental bacterial plaque detached much more easily from, and adhered less well to, surfaces modified with this silane coupling agent compared with unmodified surfaces. The surfaces of four teeth of a denture were modified with this silane coupling agent by spreading the agent on the surfaces with a small brush followed by brief drying with a hair drier. The modified tooth surfaces of the denture, which was worn for four months in a heavy smoker's oral cavity, were more stain-resistant than the unmodified tooth surfaces. It is expected that silane coupling agents containing a fluorocarbon chain will be surface modifiers for enhancement of oral health.

  10. 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.

  11. Etching and Polymerization in Fluorocarbon-Hydrogen Plasmas: Mathematical Modeling and Experimental Investigation.

    NASA Astrophysics Data System (ADS)

    Butler, Stephanie Watts

    The goal of this research was to develop an understanding of the important reactions and species involved in polymerization and selective oxide/silicon etching with and without ion bombardment in fluorocarbon/hydrogen plasmas. Through the creation and use of a computer model, the impact of flow rate, power, CF_4/H _2 feed composition, and pressure was studied. Comparisons of model predictions of gas phase species with experimentally measured concentrations and deposition/etching rates validated the model and demonstrated the influence of gas phase species and ions upon surface reactions. The assumption of complete mixing (Continuously Stirred Tank Reactor) was proven to be appropriate; it allowed the model to include gaseous expansion and run quickly. Although previous investigators postulated CF _2 to be the predominant polymer precursor, model predictions showed that CF was also important and inclusion of CF was necessary to replicate experimental results. Without ion bombardment, hydrogen appeared to significantly lower the polymerization rate by abstracting fluorine from the film or terminating chain growth. Fluorine enhanced polymerization under some conditions, which could be due to increased generation of active sites by abstraction of hydrogen from the polymer. With energetic bombardment, fluorine reduced polymerization due to etching of polymer or shortening the lifetime of adsorbed CF_{rm x}^ecies. A new parameter, E_{rm s}, was defined and shown to indicate the ion flux to the surface. The differences in polymerization for a given CF_{rm x}/F ratio could be explained by differences in ion flux. For cases of significant polymer deposition, the polymerization rate gave the illusion of ion energy independence. This research attempted to prove that polymer inhibits etching by chemically adsorbing on silicon, not by limiting diffusion of fluorine, allowing the etch rate to be represented with Langmuir-Hinshelwood kinetics. Oxide etching was not significantly

  12. Fluorocarbon thin-film deposition on polymer surfaces from low-energy polyatomic ion beams

    NASA Astrophysics Data System (ADS)

    Wijesundara, Muthu Bandage Jayathilaka

    Low energy polyatomic ion deposition is attractive for selective surface modification of advanced materials. Surface modification by fluorocarbon (FC) thin film deposition is widely used for many technological applications. Thus, polymer surface modification by FC thin film deposition was carried out using mass-separated low energy FC ion beams. X-ray photoelectron spectroscopy, atomic force microscopy and air/water contact angles were employed to examine how the FC film chemistry, morphology, and long term stability depend on incident ion structure, kinetic energy, and fluence. Molecular dynamics simulations were performed to support experimental data. 25--100 eV CF3+ and C3F 5+ ion deposition on polystyrene (PS) surface was examined. CF3+ and C3F5+ each formed a distribution of different FC functional groups on PS in amounts dependent upon the incident ion energy, structure, and fluence. Both ions deposited mostly intact upon the surface at 25 eV. The total fluorine and fluorinated carbon content were increased with ion energy. The fluorination efficiency was higher for the larger ion. The simulations revealed that the fragmentation behavior depends on the incident ion structure and its energy. The simulations also confirmed that FC ions only penetrated a few angstroms into the surface. The compositional changes of 25--100 eV CF3+ and C3F5+ ion-modified PS surfaces were examined after being exposed to atmosphere for four and eight weeks. The FC films oxidized in atmospheric conditions. Oxygen incorporation into the ion-modified surfaces increased with ion energy due to higher surface bond breakage and active site formation at high collision energy. Overall, the aging process of these ion-deposited films appeared similar to that of plasma-deposited films. Mass-selected 50 eV C3F5+ ion deposition was employed to create chemical gradient thin films on polymethylmethacrylate (PMMA) by variation of the ion fluence across the substrate surface. The surface chemistry

  13. Phase behavior, rheological property, and transmutation of vesicles in fluorocarbon and hydrocarbon surfactant mixtures.

    PubMed

    Yuan, Zaiwu; Qin, Menghua; Chen, Xiushan; Liu, Changcheng; Li, Hongguang; Hao, Jingcheng

    2012-06-26

    We present a detailed study of a salt-free cationic/anionic (catanionic) surfactant system where a strongly alkaline cationic surfactant (tetradecyltrimethylammonium hydroxide, TTAOH) was mixed with a single-chain fluorocarbon acid (nonadecafluorodecanoic acid, NFDA) and a hyperbranched hydrocarbon acid [di-(2-ethylhexyl)phosphoric acid, DEHPA] in water. Typically the concentration of TTAOH is fixed while the total concentration and mixing molar ratio of NFDA and DEHPA is varied. In the absence of DEHPA and at a TTAOH concentration of 80 mmol·L(-1), an isotropic L(1) phase, an L(1)/L(α) two-phase region, and a single L(α) phase were observed successively with increasing mixing molar ratio of NFDA to TTAOH (n(NFDA)/n(TTAOH)). In the NFDA-rich region (n(NFDA)/n(TTAOH) > 1), a small amount of excess NFDA can be solubilized into the L(α) phase while a large excess of NFDA eventually leads to phase separation. When NFDA is replaced gradually by DEHPA, the mixed system of TTAOH/NFDA/DEHPA/H(2)O follows the same phase sequence as that of the TTAOH/NFDA/H(2)O system and the phase boundaries remain almost unchanged. However, the viscoelasticity of the samples in the single L(α) phase region becomes higher at the same total surfactant concentration as characterized by rheological measurements. Cryo-transmission electron microscopic (cryo-TEM) observations revealed a microstructural evolution from unilamellar vesicles to multilamellar ones and finally to gaint onions. The size of the vesicle and number of lamella can be controlled by adjusting the molar ratio of NFDA to DEHPA. The dynamic properties of the vesicular solutions have also been investigated. It is found that the yield stress and the storage modulus are time-dependent after a static mixing process between the two different types of vesicle solutions, indicating the occurrence of a dynamic fusion between the two types of vesicles. The microenvironmental changes induced by aggregate transitions were probed by

  14. Tube radial distribution phenomenon with a two-phase separation solution of a fluorocarbon and hydrocarbon organic solvent mixture in a capillary tube and metal compounds separation.

    PubMed

    Kitaguchi, Koichi; Hanamura, Naoya; Murata, Masaharu; Hashimoto, Masahiko; Tsukagoshi, Kazuhiko

    2014-01-01

    A fluorocarbon and hydrocarbon organic solvent mixture is known as a temperature-induced phase-separation solution. When a mixed solution of tetradecafluorohexane as a fluorocarbon organic solvent and hexane as a hydrocarbon organic solvent (e.g., 71:29 volume ratio) was delivered in a capillary tube that was controlled at 10°C, the tube radial distribution phenomenon (TRDP) of the solvents was clearly observed through fluorescence images of the dye, perylene, dissolved in the mixed solution. The homogeneous mixed solution (single phase) changed to a heterogeneous solution (two phases) with inner tetradecafluorohexane and outer hexane phases in the tube under laminar flow conditions, generating the dynamic liquid-liquid interface. We also tried to apply TRDP to a separation technique for metal compounds. A model analyte mixture, copper(II) and hematin, was separated through the capillary tube, and detected with a chemiluminescence detector in this order within 4 min.

  15. Role of CF2 in the etching of SiO2, Si3N4 and Si in fluorocarbon plasma

    NASA Astrophysics Data System (ADS)

    Lele, Chen; Liang, Zhu; Linda, Xu; Dongxia, Li; Hui, Cai; Tod, Pao

    2009-03-01

    The CF2 density and etch rate of SiO2, Si3N4 and Si are investigated as a function of gas pressure and O2 flow rate in fluorocarbon plasma. As the pressure increases, the self-bias voltage decreases whereas the SiO2 etch rate increases. Previous study has shown that SiO2 etch rate is proportional to the self-bias voltage. This result indicates that other etching parameters contribute to the SiO2 etching. Generally, the CF2 radical is considered as a precursor for fluorocarbon layer formation. At a given power, defluorination of fluorocarbon under high-energy ion bombardment is a main source of fluorine for SiO2 etching. When more CF2 radical in plasma, SiO2 etch rate is increased because more fluorine can be provided. In this case, CF2 is considered as a reactant for SiO2 etching. The etch rate of Si3N4 and Si is mainly determined by the polymer thickness formed on its surface which is dominated by the CF2 density in plasma. Etching results obtained by varying O2 flow rate also support the proposition.

  16. Nanoscale mechanical and tribological properties of fluorocarbon films grafted onto plasma-treated low-density polyethylene surfaces

    NASA Astrophysics Data System (ADS)

    Cheng, Q.; Komvopoulos, K.

    2012-03-01

    Fluorocarbon (FC) films were grafted onto Ar plasma-treated low-density polyethylene (LDPE) surfaces by plasma polymerization and deposition. The evolution of the surface morphology of the grafted FC films was investigated at different scales with an atomic force microscope. Nanoscale sliding experiments performed with a surface force microscope provided insight into the nanotribological properties of Ar plasma-treated LDPE, with and without grafted FC films, in terms of applied normal load and number of sliding cycles. The observed trends are explained in the context of microstructure models accounting for morphological and structure changes at the LDPE surface due to the effects of plasma treatment (e.g., selective etching of amorphous phase, chain crosslinking and FC film grafting) and surface sliding (e.g., crystalline lamellae alignment along the sliding direction). Nanoindentation experiments elucidated the effect of plasma treatment on surface viscoelasticity and global contact stiffness. The results of this study demonstrate that plasma-assisted grafting of FC films is an effective surface modification method for tuning the nanomechanical/tribological properties of polymers.

  17. RMS roughness-independent tuning of surface wettability by tailoring silver nanoparticles with a fluorocarbon plasma polymer.

    PubMed

    Choukourov, A; Kylián, O; Petr, M; Vaidulych, M; Nikitin, D; Hanuš, J; Artemenko, A; Shelemin, A; Gordeev, I; Kolská, Z; Solař, P; Khalakhan, I; Ryabov, A; Májek, J; Slavínská, D; Biederman, H

    2017-02-16

    A layer of 14 nm-sized Ag nanoparticles undergoes complex transformation when overcoated by thin films of a fluorocarbon plasma polymer. Two regimes of surface evolution are identified, both with invariable RMS roughness. In the early regime, the plasma polymer penetrates between and beneath the nanoparticles, raising them above the substrate and maintaining the multivalued character of the surface roughness. The growth (β) and the dynamic (1/z) exponents are close to zero and the interface bears the features of self-affinity. The presence of inter-particle voids leads to heterogeneous wetting with an apparent water contact angle θa = 135°. The multivalued nanotopography results in two possible positions for the water droplet meniscus, yet strong water adhesion indicates that the meniscus is located at the lower part of the spherical nanofeatures. In the late regime, the inter-particle voids become filled and the interface acquires a single valued character. The plasma polymer proceeds to grow on the thus-roughened surface whereas the nanoparticles keep emerging away from the substrate. The RMS roughness remains invariable and lateral correlations propagate with 1/z = 0.27. The surface features multiaffinity which is given by different evolution of length scales associated with the nanoparticles and with the plasma polymer. The wettability turns to the homogeneous wetting state.

  18. 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.

  19. Plasma-deposited fluorocarbon polymer films on titanium for preventing cell adhesion: a surface finishing for temporarily used orthopaedic implants

    NASA Astrophysics Data System (ADS)

    Finke, B.; Testrich, H.; Rebl, H.; Walschus, U.; Schlosser, M.; Zietz, C.; Staehlke, S.; Nebe, J. B.; Weltmann, K. D.; Meichsner, J.; Polak, M.

    2016-06-01

    The design of a titanium implant surface should ideally support its later application in clinical use. Temporarily used implants have to fulfil requirements different from permanent implants: they should ensure the mechanical stabilization of the bone stock but in trauma surgery they should not be integrated into the bone because they will be removed after fracture healing. Finishing of the implant surface by a plasma-fluorocarbon-polymer (PFP) coating is a possible approach for preventing cell adhesion of osteoblasts. Two different low pressure gas-discharge plasma processes, microwave (MW 2.45 GHz) and capacitively coupled radio frequency (RF 13.56 MHz) plasma, were applied for the deposition of the PFP film using a mixture of the precursor octafluoropropane (C3F8) and hydrogen (H2). The thin films were characterized by x-ray photoelectron spectroscopy, Fourier transform infrared reflection absorption spectroscopy, and water contact angle measurements. Cell culture experiments show that cell adhesion and spreading of MG-63 osteoblasts were clearly reduced or nonexistent on these surfaces, also after 24 h of storage in the cell culture medium. In vivo data demonstrated that the local inflammatory tissue response for the PFP films deposited in MW and RF plasma were comparable to uncoated controls.

  20. Etch Challenges Brought by the Metal Hardmask Approach for Advanced Contact Patterning with Fluorocarbon-based Plasma

    NASA Astrophysics Data System (ADS)

    de Marneffe, Jean-Francois; Goossens, Danny; Shamiryan, Denis; Struyf, Herbert; Boullart, Werner

    2008-10-01

    In order to overcome patterning challenges brought by dimensional scaling and aggressive pitches, extreme ultra-violet (EUV) lithography has been recently pushed forward as a possible solution for IC manufacturing, allowing extended exposure latitude at sub-50nm dimensions. This work address the technological solutions used for contact holes patterning by means of EUV lithography. A metal hard-mask (MHM) approach has been selected, in order to combine the etching of high-aspect ratio features with thin EUV photoresist. The pre-metal dielectric stack covering the active fins was composed of 15nm Si3N4 as an etch-stop liner, covered by 240nm SiO2. The MHM was made of a 30nm TiN film on top of which was spun 20nm of organic underlayer and 100nm of EUV photoresist. This presentation will describe in details the various plasma processing issues and challenges met with this patterning strategy, for down to ˜50nm contact hole sizes: SiO2:TiN and SiO2:Si3N4 selectivities by means of fluorocarbon-based chemistries; loading effects; profile and mask undercut control with CCP plasma; residue cleaning.

  1. Phase behavior of fluorocarbon and hydrocarbon double-chain hydroxylated and galactosylated amphiphiles and bolaamphiphiles. Long-term shelf-stability of their liposomes.

    PubMed

    Clary, L; Gadras, C; Greiner, J; Rolland, J P; Santaella, C; Vierling, P; Gulik, A

    1999-06-01

    This paper describes the morphological characterization, by freeze-fracture electron microscopy, and the thermotropic phase behavior, by differential scanning calorimetry and/or X-ray scattering, of aqueous dispersions of various hydroxylated and galactosylated double-chain amphiphiles and bolaamphiphiles, several of them containing one or two hydrophobic fluorocarbon chains. Colloidal systems are observed in water with the hydroxylated hydrocarbon or fluorocarbon bolaamphiphiles only when they are dispersed with a co-amphiphile such as rac-1,2-dimyristoylphosphatidylcholine (DMPC) or rac-1,2-distearoylphosphatidylcholine (DSPC). Liposomes are formed providing the relative content of bolaamphiphiles does not exceed 20% mol. Most of these liposomes can be thermally sterilized and stored at room temperature for several months without any significant modification of their size and size distribution. The hydrocarbon galactosylated bolaamphiphile HO[C24][C12]Gal forms in water a lamellar phase (the gel to liquid-crystal phase transition is complete at 45 degrees C) and a Im3m cubic phase above 47 degrees C. The fluorocarbon HO[C24][F6C5]Gal analog displays a more complex and metastable phase behavior. The fluorinated non-bolaform galactosylated [F8C7][C16]AEGal and SerGal amphiphiles form lamellar phases in water. Low amounts (10% molar ratio) of the HO[C24][F6C5]Gal or HO[C24][C12]Gal bolaamphiphiles or of the single-headed [F8C7][C16]AEGal improve substantially the shelf-stability of reference phospholipon/cholesterol 2/1 liposomes. These liposomes when co-formulated with a single-headed amphiphile from the SerGal series are by far less stable.

  2. Angular dependence of etch rates in the etching of poly-Si and fluorocarbon polymer using SF6, C4F8, and O2 plasmas

    NASA Astrophysics Data System (ADS)

    Min, Jae-Ho; Lee, Gyeo-Re; Lee, Jin-Kwan; Moon, Sang Heup; Kim, Chang-Koo

    2004-05-01

    The dependences of etch rates on the angle of ions incident on the substrate surface in four plasma/substrate systems that constitute the advanced Bosch process were investigated using a Faraday cage designed for the accurate control of the ion-incident angle. The four systems, established by combining discharge gases and substrates, were a SF6/poly-Si, a SF6/fluorocarbon polymer, an O2/fluorocarbon polymer, and a C4F8/Si. In the case of SF6/poly-Si, the normalized etch rates (NERs), defined as the etch rates normalized by the rate on the horizontal surface, were higher at all angles than values predicted from the cosine of the ion-incident angle. This characteristic curve shape was independent of changes in process variables including the source power and bias voltage. Contrary to the earlier case, the NERs for the O2/polymer decreased and eventually reached much lower values than the cosine values at angles between 30° and 70° when the source power was increased and the bias voltage was decreased. On the other hand, the NERs for the SF6/polymer showed a weak dependence on the process variables. In the case of C4F8/Si, which is used in the Bosch process for depositing a fluorocarbon layer on the substrate surface, the deposition rate varied with the ion incident angle, showing an S-shaped curve. These characteristic deposition rate curves, which were highly dependent on the process conditions, could be divided into four distinct regions: a Si sputtering region, an ion-suppressed polymer deposition region, an ion-enhanced polymer deposition region, and an ion-free polymer deposition region. Based on the earlier characteristic angular dependences of the etch (or deposition) rates in the individual systems, ideal process conditions for obtaining an anisotropic etch profile in the advanced Bosch process are proposed. .

  3. Automatic fitting procedures for EPR spectra of disordered systems: matrix diagonalization and perturbation methods applied to fluorocarbon radicals.

    PubMed

    Lund, A; Andersson, P; Eriksson, J; Hallin, J; Johansson, T; Jonsson, R; Löfgren, H; Paulin, C; Tell, A

    2008-05-01

    Two types of automatic fitting procedures for EPR spectra of disordered systems have been developed, one based on matrix diagonalization of a general spin Hamiltonian, the other on 2nd order perturbation theory. The first program is based on a previous Fortran code complemented with a newly written interface in Java to provide user-friendly in and output. The second is intended for the special case of free radicals with several relatively weakly interacting nuclei, in which case the general method becomes slow. A least squares' fitting procedure utilizing analytical or numerical derivatives of the theoretically calculated spectrum with respect to the g- and hyperfine structure (hfs) tensors was used to refine those parameters in both cases. 'Rigid limit' ESR spectra from radicals in organic matrices and in polymers, previously studied experimentally at low temperature, were analyzed by both methods. Fluorocarbon anion radicals could be simulated, quite accurately with the exact method, whereas automatic fitting on, e.g. the c-C(4)F(8)(-) anion radical is only feasible with the 2nd order approximative treatment. Initial values for the (19)F hfs tensors estimated by DFT calculations were quite close to the final. For neutral radicals of the type XCF(2)CF(2)* the refinement of the hfs tensors by the exact method worked better than the approximate. The reasons are discussed. The ability of the fitting procedures to recover the correct magnetic parameters of disordered systems was investigated by fittings to synthetic spectra with known hfs tensors. The exact and the approximate methods are concluded to be complementary, one being general, but limited to relatively small systems, the other being a special treatment, suited for S=1/2 systems with several moderately large hfs.

  4. The effects of changing deposition conditions on the similarity of sputter-deposited fluorocarbon thin films to bulk PTFE

    NASA Astrophysics Data System (ADS)

    Zandona, Philip

    Solid lubrication of space-borne mechanical components is essential to their survival and the continued human exploration of space. Recent discoveries have shown that PTFE when blended with alumina nanofillers exhibits greatly improved physical performance properties, with wear rates being reduced by several orders of magnitude. The bulk processes used to produce the PTFE-alumina blends are limiting. Co-sputter deposition of PTFE and a filler material overcomes several of these limitations by enabling the reduction of particle size to the atomic level and also by allowing for the even coating of the solid lubricant on relatively large areas and components. The goal of this study was to establish a baseline performance of the sputtered PTFE films as compared to the bulk material, and to establish deposition conditions that would result in the most bulk-like film possible. In order to coax change in the structure of the sputtered films, sputtering power and deposition temperature were increased independently. Further, post-deposition annealing was applied to half of the deposited film in an attempt to affect change in the film structure. Complications in the characterization process due to increasing film thickness were also examined. Bulk-like metrics for characterization processes the included Fourier transform infrared spectroscopy (FTIR), X-ray spectroscopy (XPS), nanoindentation via atomic force microscopy, and contact angle of water on surface measurements were established. The results of the study revealed that increasing sputtering power and deposition temperature resulted in an increase in the similarity between the fluorocarbon films and the bulk PTFE, at a cost of affecting the potential of the film thicknesses, either by affecting the deposition process directly, or by decreasing the longevity of the sputtering targets.

  5. Synthesis of single- and double-chain fluorocarbon and hydrocarbon galactosyl amphiphiles and their anti-HIV-1 activity.

    PubMed

    Faroux-Corlay, B; Clary, L; Gadras, C; Hammache, D; Greiner, J; Santaella, C; Aubertin, A M; Vierling, P; Fantini, J

    2000-07-24

    Galactosylceramide (GalCer) is an alternative receptor allowing HIV-1 entry into CD4(-)/GalCer(+) cells. This glycosphingolipid recognizes the V3 loop of HIV gp120, which plays a key role in the fusion of the HIV envelope and cellular membrane. To inhibit HIV uptake and infection, we designed and synthesized analogs of GalCer. These amphiphiles and bolaamphiphiles consist of single and double hydrocarbon and/or fluorocarbon chain beta-linked to galactose and galactosamine. They derive from serine (GalSer), cysteine (GalCys), and ethanolamine (GalAE). The anti-HIV activity and cytotoxicity of these galactolipids were evaluated in vitro on CEM-SS (a CD4(+) cell line), HT-29, a CD4(-) cell line expressing high levels of GalCer receptor, and/or HT29 genetically modified to express CD4. GalSer and GalAE derivatives, tested in aqueous medium or as part of liposome preparation, showed moderate anti-HIV-1 activities (IC50 in the 20-220 microM range), whereas none of the GalCys derivatives was found to be active. Moreover, only some of these anti-HIV active analogs inhibited the binding of [3H]suramin (a polysulfonyl compound which displays a high affinity for the V3 loop) to SPC3, a synthetic peptide which contains the conserved GPGRAF region of the V3 loop. Our results most likely indicate that the neutralization of the virion through masking of this conserved V3 loop region is not the only mechanism involved in the HIV-1 antiviral activity of our GalCer analogs.

  6. VUV and Optical Emission Characterization of Fluorocarbon SiO2 Etch Processes and Correlation to Etch Feature Quality

    NASA Astrophysics Data System (ADS)

    Hsueh, H.; Dandapani, E.; McGrath, R.; Messier, R.; Ji, B.; Karwacki, E.

    2000-10-01

    Fluorocarbon discharges used for SiO2 etch were characterized using optical (OES) and VUV emission spectroscopy. Actinometry was used to monitor atomic fluorine concentration (N_F) as power, pressure and gas mix were varied. Thermal oxide films were photolithographically patterned to define 0.5-2.0 μ m trench features, and then etched in an AMAT Mark II reactor. Etch rate, selectivity and feature critical dimension were measured using SEM and other techniques. DC self-bias was also recorded for each set of process conditions. Good etch features, etch rates of 1175 Åmin, and selectivity of 7.9 were obtained for reactor operation at 750 W, 80 mTorr, and with a gas mixture of CF_4/CHF_3/Ar at 85/10/5 sccm. Etch rate, selectivity and feature critical dimensions observed have been correlated to actinometric estimates of N_F, to self-bias voltage and to OES and VUV emissions. While varying process conditions around the reference values defined above, NF was found to increase monotonically between 0.75 and 1.2x10^13/cm^3 as pressure was increased from 70 to 100 mTorr, as power was increased from 650 to 850 W, and as CF4 gas fraction was increased from 5the reference gas mixture, etch rate was found to increase (1150 to 1550 Åmin) with increasing power, and to decrease (1550 to 550 Åmin) with increasing pressure. In these cases, etch rate trend tracked the self-bias voltage established. However, when CF4 gas fraction was increased from 5Åmin, while NF concentration increased by only 15self-bias varied by only 8feature profiles, and associated reaction processes will be presented.

  7. 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.

  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 Ångstrom 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 Ångstrom-thick SiO{sub 2} layers. Our results demonstrate that development of atomic layer etching processes even for complex materials is feasible.

  9. Comparison of pulsed and downstream deposition of fluorocarbon materials from C3F8 and c-C4F8 plasmas

    NASA Astrophysics Data System (ADS)

    Martin, Ina T.; Malkov, Galiya Sh.; Butoi, Carmen I.; Fisher, Ellen R.

    2004-03-01

    Materials deposited in continuous wave (cw) and pulsed low-pressure octafluoropropane (C3F8) and octafluorocyclobutane (c-C4F8) plasmas were characterized using Fourier transform infrared spectroscopy (FTIR), x-ray photoelectron spectroscopy, static contact angle measurements, spectroscopic ellipsometry, and scanning electron microscopy (SEM). Fluorocarbon (FC) materials deposited in pulsed plasmas were less crosslinked than those deposited in cw plasmas with equivalent input powers. Within each system, higher F/C ratio materials were deposited by lowering the plasma input power/duty cycle. Using downstream depositions had a similar effect on film composition, but also resulted in decreased deposition rates. SEM analysis showed that decreases in the flexibility of the fluorocarbon films were correlated with increases in the percent of crosslinking. Additionally, the smoothness of the film surfaces suggests that polymerization processes occur on the substrate surface. Overall, films deposited in C4F8 plasmas were more crosslinked and less flexible than those deposited in C3F8 plasmas under the same conditions. The composition of the deposited FC films is correlated to the nature and relative concentrations of nascent ions previously measured in these plasma systems using plasma ion mass spectrometry. .

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

    PubMed

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

    2015-07-23

    Enthalpies of formation for 14 C2–C4 fluorinated hydrocarbons were calculated with nine popular ab initio and density functional theory methods: B3LYP, CBS-QB3, CBS-APNO, M06, M06-2X, ωB97X, G4, G4(MP2)-6X, and W1U via several series of isodesmic reactions. The recommended ideal gas phase ΔHf298° (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.

  11. Redeposition of etch products on sidewalls during SiO2 etching in a fluorocarbon plasma. I. Effect of particle emission from the bottom surface in a CF4 plasma

    NASA Astrophysics Data System (ADS)

    Min, Jae-Ho; Hwang, Sung-Wook; Lee, Gyeo-Re; Moon, Sang Heup

    2002-09-01

    The effect of etch-product redeposition on sidewall properties during the etching of step-shaped SiO2 patterns in a CF4 plasma was examined using a Faraday cage located in a transformer coupled plasma etcher. Sidewall properties were observed for two cases: with and without particles emitted from the bottom surface in normal contact with the sidewall. Particles sputtered from the bottom surface were redeposited on the sidewall, which contributes to the formation of a passivation layer on the surface of the latter. The passivation layer consisted of silicon oxide, SixOy, and fluorocarbon, CxFy, the latter comprising the major species. Ar plasma experiments confirmed that CxFy or a fluorocarbon polymer must be present on the sidewall in order for the SixOy species to be deposited on the surface. The redeposited particles, which were largely F-deficient fluorocarbon species, as evidenced by x-ray photoelectron spectroscopy analyses, functioned as precursors for fluorocarbon polymerization, resulting in a rough sidewall surface. The chemical etch rates of SiO2 were retarded by the redeposition of particles, which eventually formed a thick layer, eventually covering the bulk SiO2. Auger electron spectroscopy analyses of the sidewall surface affected by the emission from the bottom suggest that the surface consists of three distinct layers: a surface-carbon layer, a redeposition-etch combined layer, and bulk SiO2. copyright 2002 American Vacuum Society.

  12. The performance of aminoalkyl/fluorocarbon/hydrocarbon-modified xerogel coatings against the marine alga Ectocarpus crouaniorum: relative roles of surface energy and charge.

    PubMed

    Evariste, Emmanuelle; Gatley, Caitlyn M; Detty, Michael R; Callow, Maureen E; Callow, James A

    2013-01-01

    The effect of a series of xerogel coatings modified with aminoalkyl/fluorocarbon/hydrocarbon groups on the adhesion of a new test species, the filamentous brown alga Ectocarpus crouaniorum, has been explored, and compared with the green alga Ulva linza. The results showed that E. crouaniorum adhered weakly to the less polar, low wettability coatings in the series, but stronger adhesion was shown on polar, higher surface energy coatings containing aminoalkyl groups. The results from a separate series of coatings tuned to have similar surface energies and polarities after immersion in artificial seawater (ASW), but widely different surface charges, demonstrated that surface charge was more important than surface energy and polarity in determining the adhesion strength of both E. crouaniorum and U. linza on xerogel coatings. No correlation was found between adhesion and contact angle hysteresis. X-ray photoelectron spectroscopy analysis of samples after immersion in ASW confirmed the presence of charged ammonium groups on the surface of the aminoalkylated coatings.

  13. Evaluation of a mirror-polishing technique for fluorocarbon polymer surfaces for reduction of contamination from containers used in ultratrace analysis.

    PubMed

    Takenaka, M; Hayashi, M; Suzuki, I; Yamada, Y; Takamatsu, K; Kageyama, M

    1997-03-01

    A mirror-polishing technique for fluorocarbon polymer surfaces using high-precision diamond cutting tools was developed. The goal of this technique was the reduction of ultratrace elemental analysis contamination levels of containers fabricated from such mirror-polished materials. Remarkably smooth inner surfaces with degrees of flatness of 0.1 μm peak-to-valley (PTV) for containers fabricated from mirror-polished PTFE materials were obtained, in contrast to degrees of surface flatness of more than 30 μm PTV for commercially available PTFE containers. (Here, PTV denotes the difference between the highest peak and deepest valley in a scanned area of 10 × 10 μm.) Extractable impurity levels for mirror-polished PTFE container surfaces were reduced by more than 1 order of magnitude relative to those of unpolished PTFE containers. The surface conditions of the PTFE containers were observed by atomic force and scanning electron microscopy. The microphotographs so obtained suggest that the degree of surface smoothness of the containers is proportional to their ultratrace metallic contamination levels.

  14. 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.

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

    DOE PAGES

    Metzler, Dominik; Li, Chen; Engelmann, Sebastian; ...

    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

  16. Fluorocarbon-bonded magnetic mesoporous microspheres for the analysis of perfluorinated compounds in human serum by high-performance liquid chromatography coupled to tandem mass spectrometry.

    PubMed

    Liu, Xiaodan; Yu, Yingjia; Li, Yan; Zhang, Haiying; Ling, Jin; Sun, Xueni; Feng, Jianan; Duan, Gengli

    2014-09-24

    We report herein an extraction method for the analysis of perfluorinated compounds in human serum based on magnetic core-mesoporous shell microspheres with decyl-perfluorinated interior pore-walls (Fe3O4@mSiO2-F17). Thanks to the unique properties of the Fe3O4@mSiO2-F17 microspheres, macromolecules like proteins could be easily excluded from the mesoporous channels due to size exclusion effect, and perfluorinated compounds (PFCs) in protein-rich biosamples such as serum could thus be directly extracted with the fluorocarbon modified on the channel wall without any other pretreatment procedure. The PFCs adsorbed Fe3O4@mSiO2-F17 microspheres could then be simply and rapidly isolated by using a magnet, followed by being identified and quantified by LC-MS/MS (high-performance liquid chromatography coupled to tandem mass spectrometry). Five perfluorinatedcarboxylic acids (C6, C8-C11) and perfluorooctane sulfonate (PFOS) were selected as model analytes. In order to achieve the best extraction efficiency, some important factors including the amount of Fe3O4@mSiO2-F17 microspheres added, adsorption time, type of elution solvent, eluting solvent volume and elution time were investigated. The ranges of the LOD were 0.02-0.05 ng mL(-1) for the six PFCs. The recovery of the optimized method varies from 83.13% to 92.42% for human serum samples.

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

    PubMed

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

    2017-02-07

    With the increasing interest in establishing directional etching methods capable of atomic scale resolution for fabricating highly scaled electronic devices, the need for development and characterization of atomic layer etching processes, or generally etch processes with atomic layer precision, is growing. In this work, a flux-controlled cyclic plasma process is used for etching of SiO2 and Si at the Angstrom-level. This is based on steady-state Ar plasma, with periodic, precise injection of a fluorocarbon (FC) precursor (C4F8 and CHF3) and synchronized, plasma-based Ar(+) ion bombardment [D. Metzler et al., J. Vac. Sci. Technol., A 32, 020603 (2014) and D. Metzler et al., J. Vac. Sci. Technol., A 34, 01B101 (2016)]. For low energy Ar(+) ion bombardment conditions, physical sputter rates are minimized, whereas material can be etched when FC reactants are present at the surface. This cyclic approach offers a large parameter space for process optimization. Etch depth per cycle, removal rates, and self-limitation of removal, along with material dependence of these aspects, were examined as a function of FC surface coverage, ion energy, and etch step length using in situ real time ellipsometry. The deposited FC thickness per cycle is found to have a strong impact on etch depth per cycle of SiO2 and Si but is limited with regard to control over material etching selectivity. Ion energy over the 20-30 eV range strongly impacts material selectivity. The choice of precursor can have a significant impact on the surface chemistry and chemically enhanced etching. CHF3 has a lower FC deposition yield for both SiO2 and Si and also exhibits a strong substrate dependence of FC deposition yield, in contrast to C4F8. The thickness of deposited FC layers using CHF3 is found to be greater for Si than for SiO2. X-ray photoelectron spectroscopy was used to study surface chemistry. When thicker FC films of 11 Å are employed, strong changes of FC film chemistry during a cycle are seen

  18. Characterizing fluorocarbon assisted atomic layer etching of Si using cyclic Ar/C4F8 and Ar/CHF3 plasma

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

    With the increasing interest in establishing directional etching methods capable of atomic scale resolution for fabricating highly scaled electronic devices, the need for development and characterization of atomic layer etching processes, or generally etch processes with atomic layer precision, is growing. In this work, a flux-controlled cyclic plasma process is used for etching of SiO2 and Si at the Angstrom-level. This is based on steady-state Ar plasma, with periodic, precise injection of a fluorocarbon (FC) precursor (C4F8 and CHF3) and synchronized, plasma-based Ar+ ion bombardment [D. Metzler et al., J. Vac. Sci. Technol., A 32, 020603 (2014) and D. Metzler et al., J. Vac. Sci. Technol., A 34, 01B101 (2016)]. For low energy Ar+ ion bombardment conditions, physical sputter rates are minimized, whereas material can be etched when FC reactants are present at the surface. This cyclic approach offers a large parameter space for process optimization. Etch depth per cycle, removal rates, and self-limitation of removal, along with material dependence of these aspects, were examined as a function of FC surface coverage, ion energy, and etch step length using in situ real time ellipsometry. The deposited FC thickness per cycle is found to have a strong impact on etch depth per cycle of SiO2 and Si but is limited with regard to control over material etching selectivity. Ion energy over the 20-30 eV range strongly impacts material selectivity. The choice of precursor can have a significant impact on the surface chemistry and chemically enhanced etching. CHF3 has a lower FC deposition yield for both SiO2 and Si and also exhibits a strong substrate dependence of FC deposition yield, in contrast to C4F8. The thickness of deposited FC layers using CHF3 is found to be greater for Si than for SiO2. X-ray photoelectron spectroscopy was used to study surface chemistry. When thicker FC films of 11 Å are employed, strong changes of FC film chemistry during a cycle are seen

  19. Characterizing Fluorocarbon Assisted Atomic Layer Etching of Si Using Cyclic Ar/C4F8 and Ar/CHF3 Plasma

    DOE PAGES

    Metzler, Dominik; Li, Chen; Engelmann, Sebastian; ...

    2016-09-08

    With the increasing interest in establishing directional etching methods capable of atomic scale resolution for fabricating highly scaled electronic devices, the need for development and characterization of atomic layer etching (ALE) processes, or generally etch processes with atomic layer precision, is growing. In this work, a flux-controlled cyclic plasma process is used for etching of SiO2 and Si at the Angstrom-level. This is based on steady-state Ar plasma, with periodic, precise injection of a fluorocarbon (FC) precursor (C4F8 and CHF3), and synchronized, plasma-based Ar+ ion bombardment [D. Metzler et al., J Vac Sci Technol A 32, 020603 (2014), and D.more » Metzler et al., J Vac Sci Technol A 34, 01B101 (2016)]. For low energy Ar+ ion bombardment conditions, physical sputter rates are minimized, whereas material can be etched when FC reactants are present at the surface. This cyclic approach offers a large parameter space for process optimization. Etch depth per cycle, removal rates, and self-limitation of removal, along with material dependence of these aspects, were examined as a function of FC surface coverage, ion energy, and etch step length using in situ real time ellipsometry. The deposited FC thickness per cycle is found to have a strong impact on etch depth per cycle of SiO2 and Si, but is limited with regard to control over material etching selectivity. Ion energy over the 20 to 30 eV range strongly impacts material selectivity. The choice of precursor can have a significant impact on the surface chemistry and chemically enhanced etching. CHF3 has a lower FC deposition yield for both SiO2 and Si, and also exhibits a strong substrate dependence of FC deposition yield, in contrast to C4F8. The thickness of deposited FC layers using CHF3 is found to be greater for Si than for SiO2. X-ray photoelectron spectroscopy was used to study surface chemistry. When thicker FC films of 11 Å are employed, strong changes of FC film chemistry during a cycle are

  20. New Methodology for Fluorocarbon Synthesis

    DTIC Science & Technology

    1991-12-01

    Distribucion Unlimited 4. PERFORMING ORGANIZATION REPORT NUMBER(S) S. MONITORING ORGANIZATION REPORT NUMIER(S) 61. NAME OF PERFORMING ORGANIZATION F6b...Include Area Code) 22c. OFFICE SYMBOL Dr. Frod Reder 07-70;7-LThA-QA " D Form 1473, JUN 84 P’wous ed, r,on eare 6o0ee. SECURITY CLASSIFICATION OF THIS PAG...AISTRACT SECURITY CLASSIFICATION QUNCASSIFIEDIUNUMITED 0 SAME AS RAT r:C . if’.S snlas gf{.d Zia. NAME OF RESPONSIBLE INDIVIDUAL 22b. TELEPHONE (InIufe Area

  1. FLUOROCARBON N-F COMPOUNDS

    DTIC Science & Technology

    FLUORIDES, *FLUORINATED HYDROCARBONS, ALKYL RADICALS, CARBOXYLIC ACIDS, CATALYSTS , CESIUM COMPOUNDS, CHEMICAL EQUILIBRIUM, IMIDES, IMINES, MOLECULAR...STRUCTURE, NITRILES, NUCLEAR MAGNETIC RESONANCE, PROPENES, REACTION KINETICS, SUBSTITUTION REACTIONS , SULFUR COMPOUNDS, SYNTHESIS.

  2. Role of surface-reaction layer in HBr/fluorocarbon-based plasma with nitrogen addition formed by high-aspect-ratio etching of polycrystalline silicon and SiO2 stacks

    NASA Astrophysics Data System (ADS)

    Iwase, Taku; Matsui, Miyako; Yokogawa, Kenetsu; Arase, Takao; Mori, Masahito

    2016-06-01

    The etching of polycrystalline silicon (poly-Si)/SiO2 stacks by using VHF plasma was studied for three-dimensional NAND fabrication. One critical goal is achieving both a vertical profile and high throughput for multiple-stack etching. While the conventional process consists of multiple steps for each stacked layer, in this study, HBr/fluorocarbon-based gas chemistry was investigated to achieve a single-step etching process to reduce process time. By analyzing the dependence on wafer temperature, we improved both the etching profile and rate at a low temperature. The etching mechanism is examined considering the composition of the surface reaction layer. X-ray photoelectron spectroscopy (XPS) analysis revealed that the adsorption of N-H and Br was enhanced at a low temperature, resulting in a reduced carbon-based-polymer thickness and enhanced Si etching. Finally, a vertical profile was obtained as a result of the formation of a thin and reactive surface-reaction layer at a low wafer temperature.

  3. 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.

  4. Fluorocarbon assisted atomic layer etching of SiO{sub 2} and Si using cyclic Ar/C{sub 4}F{sub 8} and Ar/CHF{sub 3} plasma

    SciTech Connect

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

    2016-01-15

    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/C{sub 4}F{sub 8} ALE based on steady-state Ar plasma in conjunction with periodic, precise C{sub 4}F{sub 8} injection and synchronized plasma-based low energy Ar{sup +} ion bombardment has been established for SiO{sub 2} [Metzler et al., J. Vac. Sci. Technol. A 32, 020603 (2014)]. In this work, the cyclic process is further characterized and extended to ALE of silicon under similar process conditions. The use of CHF{sub 3} as a precursor is examined and compared to C{sub 4}F{sub 8}. CHF{sub 3} is shown to enable selective SiO{sub 2}/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. Plasma parameters during ALE are studied using a Langmuir probe and establish the impact of precursor addition on plasma properties.

  5. Characterizing Fluorocarbon Assisted Atomic Layer Etching of 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

    2016-09-08

    With the increasing interest in establishing directional etching methods capable of atomic scale resolution for fabricating highly scaled electronic devices, the need for development and characterization of atomic layer etching (ALE) processes, or generally etch processes with atomic layer precision, is growing. In this work, a flux-controlled cyclic plasma process is used for etching of SiO2 and Si at the Angstrom-level. This is based on steady-state Ar plasma, with periodic, precise injection of a fluorocarbon (FC) precursor (C4F8 and CHF3), and synchronized, plasma-based Ar+ ion bombardment [D. Metzler et al., J Vac Sci Technol A 32, 020603 (2014), and D. Metzler et al., J Vac Sci Technol A 34, 01B101 (2016)]. For low energy Ar+ ion bombardment conditions, physical sputter rates are minimized, whereas material can be etched when FC reactants are present at the surface. This cyclic approach offers a large parameter space for process optimization. Etch depth per cycle, removal rates, and self-limitation of removal, along with material dependence of these aspects, were examined as a function of FC surface coverage, ion energy, and etch step length using in situ real time ellipsometry. The deposited FC thickness per cycle is found to have a strong impact on etch depth per cycle of SiO2 and Si, but is limited with regard to control over material etching selectivity. Ion energy over the 20 to 30 eV range strongly impacts material selectivity. The choice of precursor can have a significant impact on the surface chemistry and chemically enhanced etching. CHF3 has a lower FC deposition yield for both SiO2 and Si, and also exhibits a strong substrate dependence of FC deposition yield, in contrast to C4F8. The thickness of deposited FC layers using CHF3 is found to be greater for Si than for SiO2. X-ray photoelectron spectroscopy was used to study surface chemistry

  6. 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.

  7. Nonclassical gasdynamic region of selected fluorocarbons

    NASA Astrophysics Data System (ADS)

    Guardone, A.; Argrow, B. M.

    2005-11-01

    The nonclassical gasdynamic region of fluorinated substances belonging to the PP, FC, and E series is investigated using different thermodynamic models of increasing complexity. Thermodynamic models range from the simple van der Waals equation of state to the more complex Martin-Hou model and include the Redlich-Kwong, Clausius-II, Soave-Redlich-Kwong, and Peng-Robinson equations, under both the polytropic (constant isochoric specific heat in the dilute gas limit) and nonpolytropic approximations. The possibility of observing nonclassical gasdynamic behavior for a given fluid is confirmed to increase with the molecular weight of the substance times the specific heat at constant volume in the dilute gas limit and at the critical temperature, but to be almost insensitive to the nonpolytropic behavior of the fluid; the dependence on the compressibility at the critical point is also weak. A strong dependence on the acentric factor of the substance is revealed, which points to fluids made of nonpolar molecules with nearly spheroidal shapes as the most favorable to exhibit nonclassical gasdynamic behavior. In this respect, the fluorinated cyclic compounds of the PP series are singled out as the most promising candidates for the experimental verification of the existence of nonclassical phenomena in the vapor phase and for nonclassical gasdynamic applications.

  8. Rayleigh scattering measurements of several fluorocarbon gases.

    PubMed

    Zadoo, Serena; Thompson, Jonathan E

    2011-11-01

    Integrating nephelometers are commonly used to monitor airborne particulate matter. However, they must be calibrated prior to use. The Rayleigh scattering coefficients (b(RS), Mm(-1)), scattering cross sections (σ(RS), cm(2)), and Rayleigh multipliers for tetrafluoromethane (R-14), sulfur hexafluoride, pentafluoroethane (HFC-125), hexafluoropropene (HFC-216), 1,1,1,2,3,3,3,-heptafluoropropane (HFC-227ea), and octafluorocyclobutane (C-318) are reported from measurements made using a Radiance Research M903 integrating nephelometer operating at λ = 530 nm and calibration with gases of known scattering constants. Rayleigh multipliers (±90% conf. int.) were found to be 2.6 ± 0.5, 6.60 ± 0.07, 7.5 ± 1, 14.8 ± 0.9, 15.6 ± 0.5, and 22.3 ± 0.8 times that of air, respectively. To the best of our knowledge, these are the first reported values for R-14, HFC-216, HFC-125, and C-318. Experimental accuracy is supported through measurements of values for SF(6) and HFC-227ea which agree to within 3% of previous literature reports. In addition to documenting fundamental Rayleigh scattering data for the first time, the information presented within will find use for calibration of optical scattering sensors such as integrating nephelometers.

  9. Crosslinking Chemistry for Fluorocarbon Ether Bibenzoxazole Polymers

    DTIC Science & Technology

    1979-11-01

    soluble amber- colored gums which exhibited inherent viscosities in the range of 0.26 to 0.51 dl/g were obtained in yields of up to 90 percent. N -CF ) CH...dissolved to permit the formation of a viscous, amber- colored solution. The resultant gum exhibited an inherent viscosity of 0.20 dl/g. 3. POLYMER...reaction vessel. The excess copper and cuprous salts were filtered off, the organic layer separated, and the aqueous layer extracted with more

  10. 21 CFR 177.1380 - Fluorocarbon resins.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., Extrusion, and Coating Materials,” which is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from the American Society for Testing and Materials, 1916...

  11. 21 CFR 177.1380 - Fluorocarbon resins.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., Extrusion, and Coating Materials,” which is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from the American Society for Testing and Materials, 1916...

  12. 21 CFR 177.1380 - Fluorocarbon resins.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., Extrusion, and Coating Materials,” which is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from the American Society for Testing and Materials, 1916...

  13. 21 CFR 177.1380 - Fluorocarbon resins.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Method D 3275-89 “Standard Specification for E-CTFE-Fluoroplastic Molding, Extrusion, and Coating... may be obtained from the American Society for Testing and Materials, 1916 Race St., Philadelphia,...

  14. Rubber Research. The Synthesis of Unsaturated Fluorocarbons.

    DTIC Science & Technology

    HALOGENATED HYDROCARBONS, SYNTHESIS(CHEMISTRY)), (*NITROSO COMPOUNDS, SYNTHESIS(CHEMISTRY)), FLUORINE COMPOUNDS, CHLORINE COMPOUNDS, ORGANIC SOLVENTS, ALKENES, IRON COMPOUNDS, PHOTOLYSIS, ACETIC ANHYDRIDE, ACETIC ACID

  15. 21 CFR 177.1380 - Fluorocarbon resins.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic Components...) Chlorotrifluoroethylene-1,1-difluoroethylene-tetrafluoroethylene co-polymer resins produced by copolymerization of..., Extrusion, and Coating Materials,” which is incorporated by reference in accordance with 5 U.S.C. 552(a)...

  16. Total cross section of electron scattering by fluorocarbon molecules

    NASA Astrophysics Data System (ADS)

    Yamada, T.; Ushiroda, S.; Kondo, Y.

    2008-12-01

    A compact linear electron transmission apparatus was used for the measurement of the total electron scattering cross section at 4-500 eV. Total cross sections of chlorofluorocarbon (CCl2F2), hydrochlorofluorocarbon (CHClF2), perfluoropropane (C3F8), perfluoro-n-pentane (C5F12), perfluoro-n-hexane (C6F14) and perfluoro-n-octane (C8F18) were obtained experimentally and compared with the values obtained from a theoretical calculation and semi-empirical model calculation.

  17. Attenuation of fluorocarbons released from foam insulation in landfills.

    PubMed

    Scheutz, Charlotte; Dote, Yutaka; Fredenslund, Anders M; Mosbaek, Hans; Kjeldsen, Peter

    2007-11-15

    Chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs) have been used as blowing agents (BAs) for foam insulation in home appliances and building materials, which after the end of their useful life are disposed of in landfills. The objective of this project was to evaluate the potential for degradation of BAs in landfills, and to develop a landfill model, which could simulate the fate of BAs in landfills. The investigation was performed by use of anaerobic microcosm studies using different types of organic waste and anaerobic digested sludge as inoculum. The BAs studied were CFC-11, CFC-12, HCFC-141b, HFC-134a, and HFC-245fa. Experiments considering the fate of some of the expected degradations products of CFC-11 and CFC-12 were included like HCFC-21, HCFC-22, HCFC-31, HCFC-32, and HFC-41. Degradation of all studied CFCs and HCFCs was observed regardless the type of waste used. In general, the degradation followed first-order kinetics. CFC-11 was rapidly degraded from 590 microg L(-1) to less than 5 microg L(-1) within 15-20 days. The degradation pattern indicated a sequential production of HCFC-21, HCFC-31, and HFC-41. However, the production of degradation products did not correlate with a stoichiometric removal of CFC-11 indicating that other degradation products were produced. HCFC-21 and HCFC-31 were further degraded whereas no further degradation of HFC-41 was observed. The degradation rate coefficient was directly correlated with the number of chlorine atoms attached to the carbon. The highest degradation rate coefficient was obtained for CFC-11, whereas lower rates were seen for HCFC-21 and HCFC-31. Equivalent results were obtained for CFC-12. HCFC-141b was also degraded with rates comparable to HCFC-21 and CFC-12. Anaerobic degradation of the studied HFCs was not observed in any of the experiments within a run time of up to 200 days. The obtained degradation rate coefficients were used as input for an extended version of an existing landfill fate model incorporating a time dependent BA release from co-disposed foam insulation waste. Predictions with the model indicate that the emission of foam released BAs may be strongly attenuated by microbial degradation reactions. Sensitivity analysis suggests that there is a need for determination of degradation rates under more field realistic scenarios.

  18. 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.

  19. Total and ionization cross sections of electron scattering by fluorocarbons

    NASA Astrophysics Data System (ADS)

    Antony, B. K.; Joshipura, K. N.; Mason, N. J.

    2005-02-01

    Electron impact total cross sections (50-2000 eV) and total ionization cross sections (threshold to 2000 eV) are calculated for typical plasma etching molecules CF4, C2F4, C2F6, C3F8 and CF3I and the CFx (x = 1-3) radicals. The total elastic and inelastic cross sections are determined in the spherical complex potential formalism. The sum of the two gives the total cross section and the total inelastic cross section is used to calculate the total ionization cross sections. The present total and ionization cross sections are found to be consistent with other theories and experimental measurements, where they exist. Our total cross section results for CFx (x = 1-3) radicals presented here are first estimates on these species.

  20. Effects of fluorocarbon propellants on respiratory flow and ECG.

    PubMed Central

    Valić, F; Skurić, Z; Bantić, Z; Rudar, M; Hećej, M

    1977-01-01

    Ten subjects were exposed to the propellants freon 11, freon 12, freon 114, to two mixtures of freon 11 and 12 and to a mixture of freon 12 and 114. The length of exposure was 15, 45 or 60 seconds. Maximum expiratory flow-volume (MEF) curves and ECG were recorded before, and intermittently up to 1 hour after, exposure. Breathing level concentrations of propellants during exposure were determined by gas chromatography. All freons induced biphasic reduction of ventilatory capacity on inhalation. The first fall occurred within a few minutes of exposure while the second was delayed 13-30 minutes after exposure. The effects of mixtures were greater than those of individual freons. The relative fall in MEF 75% was more pronounced than that in MEF 50%. No clear-cut pathological changes in ECG were found. Nevertheless, most subjects developed variations in heart rate exceeding those noted before exposure. In a few cases inversion of the T wave, and in one case atrioventricular block, were observed. PMID:871444

  1. Hybrid Fluorosilicones for Aircraft Fuel Tank Sealants. Part 4. Synthesis of Fluorocarbon and Fluorocarbon Ether Hybrid Fluorosilicone Polymers.

    DTIC Science & Technology

    1974-05-01

    w 0) N t- x - -HP x )0; o 0 0 - r : H z z0) 4-) * 4 x (2) to ’d c 0 10 0)4 0 0 ;4 ~ o4o c 0 * 4 30 0 0 4-H4 -T m 0 .0 d4.3 NH 0 Hd Hr H NNi H E-4 4...SO G Cefne nvers ie fnoe el end Ientfyb bok ies n ly A9TRC aCrlmse r ers seIfnsem is Idef by atc nbe er oc fl ohr sii0 n It NS etomi poymr wee...3 A. Fluorosilicone-Fluoroether Hybrid Polymers (FES) .................... 3 1. Preparation of X (CFa)*O(CF2)nO(CF2

  2. 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.

  3. 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.

  4. 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.

  5. Nanotexturing of polystyrene surface in fluorocarbon plasmas: from sticky to slippery superhydrophobicity.

    PubMed

    Mundo, Rosa Di; Palumbo, Fabio; d'Agostino, Riccardo

    2008-05-06

    In this work plasma etching processes have been studied to roughen and fluorinate polystyrene surface as an easy method to achieve a superhydrophobic slippery character. Radiofrequency discharges have been fed with CF(4)/O(2) mixtures and the effect of the O(2):CF(4) ratio, the input power, and the treatment duration have been investigated in terms of wettability, with focus on sliding performances. For this purpose, surface morphological variations, evaluated by means of scanning electron microscopy and atomic force microscopy, together with the chemical assessment by X-ray photoelectron spectroscopy, have been correlated with water contact angle hysteresis and volume resolved sliding angle measurements. Results indicate that by increasing the height and decreasing the density of the structures formed by etching, within a tailored range, a transition from sticky to slippery superhydrophobicity occurs. A short treatment time (5 min) is sufficient to obtain such an effect, provided that a high power input is utilized. Optimized surfaces show a unaltered transparency to visible light according to the low roughness produced.

  6. Design Rules for Fluorocarbon-Free Omniphobic Solvent Barriers in Paper-Based Devices.

    PubMed

    Jahanshahi-Anbuhi, Sana; Pennings, Kevin; Leung, Vincent; Kannan, Balamurali; Brennan, John D; Filipe, Carlos D M; Pelton, Robert H

    2015-11-18

    The utility of hydrophobic wax barriers in paper-based lateral flow and multiwell devices for containment of aqueous solvents was extended to organic solvents and challenging aqueous surfactant solutions by preparation of a three layer barrier, consisting of internal pullulan impregnated paper barriers surrounded by external wax barriers. When paper impregnated with pullulan solution dries, the polymer forms solvent blocking lenses in the paper structure. Lens formation was illustrated by forming pullulan lenses in glass capillaries. The lens shapes were less curved compared to the predictions of a model based upon minimizing surface area. For barriers on Whatman # 1 filter paper, the pullulan molecular weight must be greater than ∼70 kDa, the mass fraction of pullulan in the barrier zone must be at least 32%, and there are restrictions on the minimum width of the pullulan impregnated zone.

  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. 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.

  9. 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.

  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. Charged Particle Dynamics in a Dual-Frequency Capacitively Coupled Fluorocarbon Plasma

    NASA Astrophysics Data System (ADS)

    Marić, Dragana; Curley, Garrett; Booth, Jean-Paul; Chabert, Pascal; Guillon, Jean

    2006-10-01

    We are studying a customized 2 + 27.12 MHz industrial etch reactor, running in Ar/O2 with c-C4F8 or CF4 gas mixtures at pressures in the region of 50 mTorr. Independent control of ion flux and ion energy is an advantage of DFC plasmas, but little experimental data exists regarding the charged particle dynamics in complex industrial gas mixtures. Negative ions could play an important role in this type of plasma. The presence of negative ions will modify the positive ion flux arriving at a surface, and may even reach the surface and participate in etching. We measure the electron density using a microwave hairpin resonator and the positive ion flux with an ion flux probe: the ratio of these two quantities varies strongly with gas chemistry and gives evidence for the presence of negative ions. We have measured high electronegativity for high c-C4F8 flowrates. We have also examined the effect of varying the 2 MHz and 27.12 MHz powers on both the electron density and positive ion flux. This allows us to estimate the effect of varying power on the negative ion density. In addition CRDS was used to measure the F^- density[1]. This optical measurement will be compared to the probe technique. [1] Booth et al, Appl. Phys. Lett. 88 (2006) 151502

  12. 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.

  13. 40 CFR Appendix A to Subpart F of... - Specifications for Fluorocarbon and Other Refrigerants

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 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 be... tanks and cylinders. 5.9.2Method. The test method shall be gas chromatography with a...

  14. 40 CFR Appendix A to Subpart F of... - Specifications for Fluorocarbon and Other Refrigerants

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 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 be... tanks and cylinders. 5.9.2Method. The test method shall be gas chromatography with a...

  15. 40 CFR Appendix A to Subpart F of... - Specifications for Fluorocarbon and Other Refrigerants

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 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 be... tanks and cylinders. 5.9.2Method. The test method shall be gas chromatography with a...

  16. 40 CFR Appendix A to Subpart F of... - Specifications for Fluorocarbon and Other Refrigerants

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 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 be... tanks and cylinders. 5.9.2Method. The test method shall be gas chromatography with a...

  17. 40 CFR Appendix A to Subpart F of... - Specifications for Fluorocarbon and Other Refrigerants

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 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 be... tanks and cylinders. 5.9.2Method. The test method shall be gas chromatography with a...

  18. Release of fluorocarbons from insulation foam in home appliances during shredding.

    PubMed

    Scheutz, Charlotte; Fredenslund, Anders M; Kjeldsen, Peter; Tant, Michael

    2007-12-01

    It is a current practice that refrigerators and freezers in many countries are shredded after the end of useful lives. The shredder residue is deposited in landfills. During the shredding process a significant fraction of blowing agent (BA) in the insulation foam may be released into the atmosphere. The objective of this study is to determine the fraction of BA released from foam during shredding, by comparing the BA content in insulation foam of refrigerator units before shredding with the BA content of shredded foam. All foam samples analyzed were manufactured with trichlorofluoromethane [CFC-11 (CCl3F)] as BA. The average content of BA in the insulation foam from eight U.S. refrigerator units manufactured before 1993 was found to be 14.9% +/- 3.3% w/w. Several refrigerator units also identified as being manufactured before 1993 were stockpiled and shredded at three shredder facilities, of which one was operated in both wet and dry modes. The selected shredder facilities represent typical American facilities for shredding automobiles, refrigerators, freezers, and other iron containing waste products. Shredded material was collected and separated on location into four particle size categories: more than 32 mm, 16-32 mm, 8-16 mm, and 0-8 mm. Adjusting for sample purity, it was found that the majority (>81%) of the foam mass was shredded into particles larger than 16 mm. The smallest size fraction of foam (0-8 mm) was found to contain significantly less BA than the larger size categories, showing that up to 68% +/- 4% of the BA is released from these fine particles during the shredding process. Because only a minor fraction of the foam is shredded into particles smaller than 8 mm, this has a minor impact on the end result when calculating the total BA release from the shredding process. Comparing BA content in shredded samples from the three shredder facilities with the measured average BA content of the eight refrigerator units, it was found that on average 24.2% +/- 7.5% of the initial BA content is released during the shredding process.

  19. 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.

  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. Correlating ion energies and CF2 surface production during fluorocarbon plasma processing of silicon

    NASA Astrophysics Data System (ADS)

    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 C3F8 and C4F8 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 29to92eV. 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 CF2 surface interaction measurements previously made in our laboratories reveals that mean ion energies are directly and linearly correlated to CF2 surface production in these systems.

  2. Time resolved studies on pulsed fluorocarbon plasmas using chirped quantum cascade lasers

    NASA Astrophysics Data System (ADS)

    Welzel, S.; Stepanov, S.; Meichsner, J.; Röpcke, J.

    2010-03-01

    The kinetics of stable species has been studied in situ in pulsed CF4/H2 radio frequency discharges by means of time resolved quantum cascade laser absorption spectroscopy. The absorption spectra were usually recorded with a time resolution of 5 ms and required a multi-species analysis, because of interfering complex absorption features of CF4 and C3F8. For this reason, measurements were carried out at two different spectral positions. High resolution spectroscopic data were established by calibrating effective absorption cross sections and their relative temperature dependences for the relevant low pressure conditions (10 Pa). During the discharge a decrease in the CF4 density by ~12% was observed. The off-phase was characterized mainly by the gas exchange. The C3F8 density in the off-phase was found to be of the order of the detection limit (3 × 1013 cm-3). Spectra acquired during the plasma-on phase showed a rapid temperature-induced increase in the absorption signal and, additionally, suggested the influence of a short-lived broadband absorbing species. The reasonable assumption of the presence of CF4 hotbands has not yet enabled a further quantification.

  3. 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.

  4. Creation of fluorocarbon barriers on surfaces of starch-based products through cold plasma treatment

    NASA Astrophysics Data System (ADS)

    Han, Yousoo

    Two kinds of starch foam trays (starch and aspen-starch foam trays) were produced using a lab model baking machine. Surfaces of the trays were treated with CF4 and SF6 plasma to create fluorine-rich layers on the surfaces, which might show strong water resistance. The plasma parameters, such like RF power, gas pressure and reaction time, were varied to evaluate the effects of each parameter on fluorination of surfaces. The atomic concentrations of fluorine, oxygen and carbon on samples' surfaces were earned from ESCA (electron spectroscopy for chemical analysis) and contact angles of sample surfaces were measured for hydrophobicity. For water resistance of plasma treated surfaces, liquid water uptake and water vapor uptake test were performed. Also, equilibrium moisture contents of unmodified and plasma treated samples were measured to evaluate biodegradability of plasma treated samples. Fluorine-rich barriers were created on sample surfaces treated with CF 4 and SF6 plasma. The fluorine atomic concentrations of treated sample surfaces were ranged from 34.4% to 64.4% (CF4 treatment) and 43.6% to 57.9% (SF6 treatment). It was found at both plasma gases that plasma parameters affected total fluorine concentration and carbon-peak shapes in ESCA surveys, which imply different distributions of mono- or multi-fluoro carbon's contents. In various reaction times, it was found that total fluorine contents were decreased after a critical point as the reaction time was prolonged, which may imply that a dominant mechanism has been changed from deposition or functionalization to etching. Oxygen atomic concentration was decreased at sample surfaces treated by both plasmas. In the case of SF6 plasma, it was proved that the removal of oxygen surely occurred because there was no addition of sulfur species. Plasma treated sample surfaces had high contact angles with distilled water up to 150° and the high values of angles have been kept constant up to for 15 minutes. Fluorine-rich barriers created by plasma showed lower water liquid and vapor permeability than untreated surfaces did. Plasma treated samples had similar moisture contents with untreated samples at all relative humidity tested. AFM and SEM images were taken for sample surfaces' morphology and topography.

  5. 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.; Miljanić, Ognjen Š.

    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-H···N] hydrogen bonds between the terminal pyrazole rings and [π···π] 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 fluorocarbons—the latter two being ozone-depleting substances and potent greenhouse species—with weight capacities of up to 75%.

  6. 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.

  7. 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.

  8. Elastohydrodynamic film thickness measurements with advanced ester, fluorocarbon, and polyphenyl ether lubricants to 589 K (600 F)

    NASA Technical Reports Server (NTRS)

    Parker, R. J.; Kannel, J. W.

    1971-01-01

    Elastohydrodynamic (EHD) film thicknesses have been measured, by means of an X-ray technique, under conditions that closely simulate the ball-race contact in advanced turbine engine thrust bearings. The experiments were conducted with a rolling-disk machine using disks which yield a contact zone similar to that in the actual bearing. Both the rolling and spinning motions of the ball relative to the race were simulated by the apparatus. Four lubricants were evaluated at temperatures to 600 F and maximum Hertz stresses to 350,000 psi. The X-ray film thickness data correlated well with observations of surface distress (or lack thereof) in full-scale bearing tests with the same lubricants under similar conditions of temperature and load. The predicted variation of film thickness with speed and viscosity as verified, although the magnitude of measured film thickness was generally one-half to one-third of predicted values. An effect of stress greater than predicted was consistently observed in the higher stress range.

  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. Direct fluorination of nitrogen-containing ladder polymers, two new [open quotes]graphitic[close quotes] fluorocarbon polymers

    SciTech Connect

    Kampa, J.J.; Lagow, R.J. )

    1993-04-01

    Paracyanogen and pyrolyzed poly(acrylonitrile) have been perfluorinated using elemental fluorine and have retained their polymeric fused ring structures. The two new materials produced by this method were characterized by infrared spectroscopy, electron impact mass spectrometry, elemental analysis, iodometric titration, and thermogravimetric analysis. Some chemical and physical properties are discussed as well as several possible applications in light of the discussed properties of these materials. 21 refs., 4 figs., 3 tabs.

  11. 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.

  12. Fluorocarbon compatibilized gold-silica nanocomposites for recyclable regioselective hydroamination of alkynes in a fluorous biphasic system

    NASA Astrophysics Data System (ADS)

    Merican, Zulkifli; Vu, Bao Khanh; Solovyeva, Vera A.; Rodionov, Valentin O.; Khe, Cheng Seong; Rajalingam, Sokkalingam; Vasant, Pandian

    2016-11-01

    The synthesis and characterization of the mesoporous silica-supported gold (Au@mSiO2) nanoparticles compatibilized with the outer shelled superhydrophobic fluorous (F) "tails" was described. The concept of fluorous biphasic separation was applied in the recycling of the synthesized fluorous material during hydroamination reactions of various alkynes. In the presence of perfluoromethylcyclohexane and heptane as a biphasic liquid system, the F-Au@mSiO2 was found to be a highly active catalyst for hydroamination of various alkynes with anilines, and a near quantitative yield for an imine product and produced a relatively minimal formation of a corresponding hydrolyzed ketone by-product. If perfluoromethylcyclohexane and heptane was used as a biphasic solvent, hydroamination at a lower reaction temperature can also be realized leading to an improved recyclability and conversion.

  13. A Robust Metal-Organic Framework Combining Open Metal Sites and Polar Groups for Methane Purification and CO2 /Fluorocarbon Capture.

    PubMed

    Chen, Cheng-Xia; Zheng, Shao-Ping; Wei, Zhang-Wen; Cao, Chen-Chen; Wang, Hai-Ping; Wang, Dawei; Jiang, Ji-Jun; Fenske, Dieter; Su, Cheng-Yong

    2017-02-08

    A 3D porous perchlorinated metal-organic framework (MOF), LIFM-26, featuring dual functionality, that is, functional polar groups and open metal sites, has been synthesized using perchlorinated linear dicarboxylate to link trigonal prismatic Fe3 (μ3 -O) units. LIFM-26 exhibits good thermal and chemical stability, and possesses high porosity with a BET surface area of 1513 m(2)  g(-1) , compared with isoreticular MOF-235 and Fe3 O(F4 BDC)3 (H2 O)3 (F4 BDC=2,3,5,6-tetrafluorobenzene-1,4-dicarboxylate). Most strikingly, LIFM-26 features good gas sorption/separation performance at 298 K and 1 atm with IAST selectivity values reaching up to 36, 93, 23, 11, 46, and 202 for CO2 /CH4 , CO2 /N2 , C2 H4 /CH4 , C2 H6 /CH4 , C3 H8 /CH4 , and R22/N2 (R22=CHClF2 ), respectively, showing potential for use in biogas/natural gas purification and CO2 /R22 capture.

  14. 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.

  15. 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.

  16. Shock wave studies of the pyrolysis of fluorocarbon oxygenates. I. The thermal dissociation of C3F6O and CF3COF.

    PubMed

    Cobos, C J; Hintzer, K; Sölter, L; Tellbach, E; Thaler, A; Troe, J

    2017-01-25

    The thermal decomposition of hexafluoropropylene oxide, C3F6O, to perfluoroacetyl fluoride, CF3COF, and CF2 has been studied in shock waves highly diluted in Ar between 630 and 1000 K. The measured rate constant k1 = 1.1 × 10(14) exp(-162(±4) kJ mol(-1)/RT) s(-1) agrees well with literature data and modelling results. Using the reaction as a precursor, equimolar mixtures of CF3COF and CF2 were further heated. Combining experimental observations with theoretical modelling (on the CBS-QB3 and G4MP2 ab initio composite levels), CF3COF is shown to dissociate on two channels, either leading to CF2 + COF2 or to CF3 + FCO. By monitoring the CF2 signals, the branching ratio was determined between 1400 and 1900 K. The high pressure rate constants for the two channels were obtained from theoretical modelling as k5,∞(CF3COF → CF2 + COF2) = 7.1 × 10(14) exp(-320 kJ mol(-1)/RT) s(-1) and k6,∞(CF3COF → CF3 + FCO) = 3.9 × 10(15) exp(-355 kJ mol(-1)/RT) s(-1). The experimental results obtained at [Ar] ≈ 5 × 10(-6) mol cm(-3) were consistent with modelling results, showing that the reaction is in the falloff range of the unimolecular dissociation. The mechanism of secondary reactions following CF3COF dissociation has been analysed as well.

  17. New Insulation Constructions for Aerospace Wiring Applications. Volume 1. Testing and Evaluation

    DTIC Science & Technology

    1991-06-01

    029 - 2.0 NIL POLYIMIDE, 0.5 MIL FEP 2919 - 0.5 NIL FLUOROCARBON ( PTFE ), I NIL POLYIMIDE, 0.5 NIL FLUOROCARBON ( PTFE ) 616 - 0.1 NIL FLUOROCARBON ( FEP ...I MIL POLYIMIDE, 0.1 MIL FLUOROCARBON ( FEP ) XL - CROSSLINKED OL - OVERLAP ETFE - ETHYLENE TETRAFLUOROETHYLENE PTFE - POLY TETRAFLUOROETHYLENE 2 -4...KAPTON (50% MIN. (136 TO 138) OL) / PTFE DISPERSION * FILOTEX FILOTEX PTFE EXTRUSION / 616 KAPTON (50% MIN. (236 TO 238) OL) / FEP DISPERSION FILOTEX

  18. Emergency and Continuous Exposure Limits for Selected Airborne Contaminants. Volume 2

    DTIC Science & Technology

    1984-10-01

    21, fluorocarbon 113, fluorocarbon 114, isopropyl alcohol, phosgene, sodium hydroxide, sulfur dioxide, vinylidene chloride . xylene. b. Identlflers/Open...fluorocarbon 114, isopropyl alcohol, phosgene, sodium hydroxide, sulfur dioxide, vinylidene chloride , xylene. c. COSATI Field/Group 1I. Availability Statement...Hydroxide 87 Sulfur Dioxide 95 Vinylidene Chloride 103 Xylene 113 -" , 0°. •. .. : V.•. ., , • .’’-.’ .’.’ INTRODUCTION The National Research Council’s

  19. Recovery of purified helium or hydrogen from gas mixtures

    DOEpatents

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

    1974-01-15

    A process is described for the removal of helium or hydrogen from gaseous mixtures also containing contaminants. The gaseous mixture is contacted with a liquid fluorocarbon in an absorption zone maintained at superatomspheric pressure to preferentially absorb the contaminants in the fluorocarbon. Unabsorbed gas enriched in hydrogen or helium is withdrawn from the absorption zone as product. Liquid fluorocarbon enriched in contaminants is withdrawn separately from the absorption zone. (10 claims)

  20. 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)

  1. 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.

  2. 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.

  3. Long lived microbubbles for oxygen delivery.

    PubMed

    Gerber, Frédéric; Waton, Gilles; Krafft, Marie Pierre; Vandamme, Thierry F

    2007-01-01

    Exceptionally long lived microbubbles containing a fluorocarbon as part of their filling gas have been obtained by using a fluorinated phospholipid instead of a standard phospholipid as shell component. An unexpected, strong synergistic effect between the fluorocarbon gas and the fluorinated phospholipid has been discovered. Such bubbles could be used for in vivo oxygen delivery, ultrasound contrast imaging and drug delivery.

  4. 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.

  5. 30 CFR 7.86 - Test equipment and specifications.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... range used above 155 parts per million (ppm) or parts per million equivalent carbon (ppmC) or ±2 percent... balance shall be helium. The mixture shall contain ≤ 1 part per million equivalent carbon (ppmC), and... filters shall— (i) Be fluorocarbon-coated glass fiber filters or fluorocarbon-based (membrane) filters...

  6. 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.

  7. 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.

  8. Evaluation of Synthetic Fuel for Army Ground Applications Tasks II-VI

    DTIC Science & Technology

    2007-06-29

    Fluorocarbon (Viton) 27245 Seal, O-ring (cam ring/hyd head) Fluorocarbon (Viton) 27601 Seal, O-ring Fluorocarbon (Viton) 27608 Seal, (transfer pump... 27601 27608 11507 24585 27609 27610 27163 27602 27607 27W 1417010008 1410210503 1410210501 1410210041 7603014106 5234281 1148718 129888...Rod Guide 5331~1-236~476 27601 Viton TM 9-�-465-24P Seal, 0-Ring, Adv Plug 5331~1-399-2160 29282 Viton TM 9-�-465-24P Seal, 0-Ring, Adv Plug

  9. 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.

  10. Low-temperature radiation-resistant material for ball-bearing retainers

    NASA Technical Reports Server (NTRS)

    Desau, P. O.; Emmons, W. F.

    1970-01-01

    Radiation resistant material, made of polyimide polymers and S-glass cloth, is used in ball bearing retainers for extreme environments. Material displays satisfactory wear resistance, lubricity, and stability. Results of comparative tests with fluorocarbon materials are given.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. Synthesis of new high performance lubricants and solid lubricants. Progress report, April 1992--March 1993

    SciTech Connect

    Lagow, R.J.

    1993-04-01

    Synthesis and testing was begun on a number of new classes of lubricants: perfluoropolyethers (branching effects), perfluoromethylene oxide ethers, chlorine-substituted fluorocarbon polyethers, fluorine-containing branched ether lubricants, glycerine- based perfluoropolyesters, perfluoro epoxy ether chains, etc.

  19. Synthesis of new high performance lubricants and solid lubricants

    SciTech Connect

    Lagow, R.J.

    1993-04-01

    Synthesis and testing was begun on a number of new classes of lubricants: perfluoropolyethers (branching effects), perfluoromethylene oxide ethers, chlorine-substituted fluorocarbon polyethers, fluorine-containing branched ether lubricants, glycerine- based perfluoropolyesters, perfluoro epoxy ether chains, etc.

  20. 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.

  1. 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...

  2. 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...

  3. 16 CFR 423.1 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 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...

  4. 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...

  5. Ultrasonic Weld Sealing of M55 Stab Detonators

    DTIC Science & Technology

    1981-01-01

    Single-base Fluorocarbon HIGH EXPLOSIVES PRIMERS Cannon Electric Pistol Shot Stab Lithium aluminum hydride Magnesium hydride Bromine...trifluoride Nitronium perchlorate Fluoboric acid Inhibited red fuming nitric acid (IRFNA) Phosphorus sesquisulfide, red phosphorus and potassium

  6. All-electric gas detector

    NASA Technical Reports Server (NTRS)

    Margolis, J. S.

    1979-01-01

    Modified optoacoustic gas detector identifies gases by measuring pressure-induced voltage charge in electric signals. Can detect water vapor, atmospheric fluorocarbons, or certain nitrous or nitric compounds that indicate presence of explosives.

  7. 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)

  8. 40 CFR 414.30 - Applicability; description of the other fibers subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Fibers (85% Polyacrylonitrile) *Cellulose Acetate Fibers *Fluorocarbon (Teflon) Fibers *Modacrylic Fibers... fibers subcategory. 414.30 Section 414.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORGANIC CHEMICALS, PLASTICS, AND SYNTHETIC FIBERS Other...

  9. 40 CFR 414.30 - Applicability; description of the other fibers subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Fibers (85% Polyacrylonitrile) *Cellulose Acetate Fibers *Fluorocarbon (Teflon) Fibers *Modacrylic Fibers... fibers subcategory. 414.30 Section 414.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORGANIC CHEMICALS, PLASTICS, AND SYNTHETIC FIBERS Other...

  10. 40 CFR Appendix Vii to Part 261 - Basis for Listing Hazardous Waste

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-Dimethylhydrazine (UDMH). K108 1,1-Dimethylhydrazine (UDMH). K109 1,1-Dimethylhydrazine (UDMH). K110 1,1... Tetrachloroethylene, methylene chloride trichloroethylene, 1,1,1-trichloroethane, carbon tetrachloride, chlorinated fluorocarbons. F002 Tetrachloroethylene, methylene chloride, trichloroethylene,......

  11. Multinuclear Magnetic Resonance Imaging and NMR Spectroscopy in Biomedical Investigations

    NASA Astrophysics Data System (ADS)

    Pirogov, Yury A.

    Biomedical investigations with small animals using 0.5-T and 7-T MRI scanners adjusted on the Larmor frequencies of different nuclei 1H, 2H, 11B, 13C, 19F, 23Na, 31P, 35Cl are described. Experiments on registration of signals 19F from the fluorocarbons injected in laboratory animals are discussed. They give presentation on the application of fluorocarbon compounds as blood substitutes and contrasting preparations in MRI diagnostics. A blood substitute product fluorocarbon Perfluoranum® 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 Perfluoranum® chemical formula creates a new compounds with high MRI contrast efficiencies at Larmor frequencies of protons so and fluorine-19 nuclei.

  12. 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.

  13. The structure of fluid trifluoromethane and methylfluoride

    NASA Astrophysics Data System (ADS)

    Neuefeind, J.; Fischer, H. E.; Schröer, W.

    2000-10-01

    We present hard x-ray and neutron diffraction measurements on the polar fluorocarbons HCF3 and H3CF under supercritical conditions and for a range of molecular densities spanning about a factor of ten. The Levesque-Weiss-Reatto inversion scheme has been used to deduce the site-site potentials underlying the measured partial pair distribution functions. The orientational correlations between adjacent fluorocarbon molecules - which are characterized by quite large dipole moments but no tendency to form hydrogen bonds - are small compared to a highly polar system like fluid hydrogen chloride. In fact, the orientational correlations in HCF3 and H3CF are found to be nearly as small as those of fluid CF4, a fluorocarbon with no dipole moment.

  14. 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.

  15. Study of Brayco Corrosion Inhibitor Additive in MIL-PRF-23699 Class C/I Turbine Oil

    DTIC Science & Technology

    2007-11-02

    Elastomer compatibility testing was performed to determine the effect of the blends on nitrile and fluorocarbon elastomers. The test was performed using...materials indicative of those seen in engine or gearbox O-rings and is run at 70°C (158°F) for nitrile rubber and 204°C (400°F) for fluorocarbon rubber ...unknown, a study was initiated by AIR-4.4.5 to access the physical and chemical properties of the oil blended with Brayco 599. This report only

  16. Vacuum ultraviolet radiation/atomic oxygen synergism in materials reactivity

    NASA Technical Reports Server (NTRS)

    Koontz, Steven; Leger, Lubert; Albyn, Keith; Cross, Jon

    1990-01-01

    Experimental results are presented which indicate that low fluxes of vacuum UV (VUV) radiation exert a pronounced influence on the atomic oxygen reactivity of such fluorocarbon and fluorocarbon spacecraft materials as the FEP Teflon and PCTFE that are under consideration for the Space Station Freedom. With simultaneous exposure to VUV fluxes comparable to those experienced in LEO, the reactivity of these materials becomes comparable to that of Kapton; VUV radiation has also been shown to increase the reactivity of Kapton with thermal-energy oxygen atoms.

  17. 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%.

  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}. 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%.

  19. 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.

  20. Compatibility Assessment of Fuel System Elastomers with Bio-oil and Diesel Fuel

    SciTech Connect

    Kass, Michael D.; Janke, Christopher J.; Connatser, Raynella M.; Lewis, Samuel A.; Keiser, James R.; Gaston, Katherine

    2016-08-18

    Bio-oil derived via fast pyrolysis is being developed as a renewable fuel option for petroleum distillates. The compatibility of neat bio-oil with six elastomer types was evaluated against the elastomer performance in neat diesel fuel, which served as the baseline. The elastomers included two fluorocarbons, six acrylonitrile butadiene rubbers (NBRs), and one type each of fluorosilicone, silicone, styrene butadiene rubber (SBR), polyurethane, and neoprene. Specimens of each material were exposed to the liquid and gaseous phases of the test fuels for 4 weeks at 60 degrees C, and properties in the wetted and dried states were measured. Exposure to bio-oil produced significant volume expansion in the fluorocarbons, NBRs, and fluorosilicone; however, excessive swelling (over 80%) was only observed for the two fluorocarbons and two NBR grades. The polyurethane specimens were completely degraded by the bio-oil. In contrast, both silicone and SBR exhibited lower swelling levels in bio-oil compared to neat diesel fuel. The implication is that, while polyurethane and fluorocarbon may not be acceptable seal materials for bio-oils, silicone may offer a lower cost alternative.

  1. Compatibility Assessment of Fuel System Elastomers with Bio-oil and Diesel Fuel

    SciTech Connect

    Kass, Michael D.; Janke, Christopher J.; Connatser, Raynella M.; Lewis, Samuel A.; Keiser, James R.; Gaston, Katherine

    2016-07-12

    Here we report that bio-oil derived via fast pyrolysis is being developed as a renewable fuel option for petroleum distillates. The compatibility of neat bio-oil with six elastomer types was evaluated against the elastomer performance in neat diesel fuel, which served as the baseline. The elastomers included two fluorocarbons, six acrylonitrile butadiene rubbers (NBRs), and one type each of fluorosilicone, silicone, styrene butadiene rubber (SBR), polyurethane, and neoprene. Specimens of each material were exposed to the liquid and gaseous phases of the test fuels for 4 weeks at 60 °C, and properties in the wetted and dried states were measured. Exposure to bio-oil produced significant volume expansion in the fluorocarbons, NBRs, and fluorosilicone; however, excessive swelling (over 80%) was only observed for the two fluorocarbons and two NBR grades. The polyurethane specimens were completely degraded by the bio-oil. In contrast, both silicone and SBR exhibited lower swelling levels in bio-oil compared to neat diesel fuel. The implication is that, while polyurethane and fluorocarbon may not be acceptable seal materials for bio-oils, silicone may offer a lower cost alternative.

  2. Development of Hydrophobic Coatings for Water-Repellent Surfaces Using Hybrid Methodology

    DTIC Science & Technology

    2014-04-01

    water-repellent, and antimicrobial properties . Several approaches have been investigated for the development of hydrophobic and superhydrophobic... liquid precursors with different fluorocarbon structures and deposition time varied as well as the SiO2 nanoparticle loading. These parameters varied to...4 1 1. Introduction Coatings that impart hydrophobic properties are of considerable interest. For applications such as aircraft

  3. 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.…

  4. 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,…

  5. 40 CFR 261.31 - Hazardous wastes from non-specific sources.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-trichloroethane, carbon tetrachloride, and chlorinated fluorocarbons; all spent solvent mixtures/blends used in... these spent solvents and spent solvent mixtures (T) F002 The following spent halogenated solvents... spent solvent mixtures/blends containing, before use, a total of ten percent or more (by volume) of...

  6. 15 CFR Supplement No. 1 to Part 774 - The Commerce Control List

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 60 weight percent or more nickel and UF6-resistant fluorinated hydrocarbon polymers, as appropriate... less than 1,000 cm3/min.; b.3. Gaseous diffusion barriers made of porous metallic, polymer or ceramic...., made of or lined with suitable plastic materials such as fluorocarbon polymers or lined with glass);...

  7. 10 CFR Appendix E to Part 110 - Illustrative List of Chemical Exchange or Ion Exchange Enrichment Plant Equipment and Components...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., immiscible liquid phases (aqueous and organic) are countercurrently contacted to give the cascading effect of...; the organic phase consists of an extractant containing uranium chloride in an organic solvent. The.... Plastic, plastic-lined (including use of fluorocarbon polymers) and/or glass-lined columns and piping...

  8. 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...

  9. 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.

  10. 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.

  11. Gas mixtures for spark gap closing switches

    DOEpatents

    Christophorou, Loucas G.; McCorkle, Dennis L.; Hunter, Scott R.

    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.

  12. 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

  13. Liquid breathing - Prevention of pulmonary arterial-venous shunting during acceleration.

    NASA Technical Reports Server (NTRS)

    Sass, D. J.; Ritman, E. L.; Caskey, P. E.; Banchero, N.; Wood, E. H.

    1972-01-01

    Dependent pulmonary atelectasis, arterial-venous shunting, and downward displacement of the heart caused by the gravitational-inertial force environment were prevented in dogs breathing oxygenated liquid fluorocarbon in a whole-body water-immersion respirator. Partial closure of the major airways during part of the expiratory phase of liquid respiration was a significant problem initially but was minimized in subsequent studies.

  14. 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.

  15. 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.

  16. Nanoenergetics and High Hydrogen Content Materials for Space Propulsion

    DTIC Science & Technology

    2012-09-01

    nanoparticles in crystals for propellants, 3) disrupting ignition of aluminum with fluorocarbon inclusions, 4) the combustion of micron aluminum with hydrogen... size on melting, diffusion, and reactions, 7) the pyrophoricity of nano-aluminum particles, 8) the thermal decomposition and high temperature...found that different mixing techniques (hand, planetary and resonant mixers , duration and temperature), or equivalence ratio gave rise to different

  17. Derivation of Navy Occupational Exposure Limits (OELS) for Two Solvent Compounds: Vertrel MCA and HFE-71DE

    DTIC Science & Technology

    2003-03-01

    able to use the solvent HFC-141b after 31 December 2002 because of a ban on its manufacture. The Navy is considering both Vertrel MCA and HFE-71DE as...replacements for HFC-141b. Both solvents are azeotropic mixtures consisting of trans 1,2-DCE and either fluorocarbons or ethers Both Vertrel MCA and

  18. Compatibility Assessment of Fuel System Elastomers with Bio-oil and Diesel Fuel

    DOE PAGES

    Kass, Michael D.; Janke, Christopher J.; Connatser, Raynella M.; ...

    2016-07-12

    Here we report that bio-oil derived via fast pyrolysis is being developed as a renewable fuel option for petroleum distillates. The compatibility of neat bio-oil with six elastomer types was evaluated against the elastomer performance in neat diesel fuel, which served as the baseline. The elastomers included two fluorocarbons, six acrylonitrile butadiene rubbers (NBRs), and one type each of fluorosilicone, silicone, styrene butadiene rubber (SBR), polyurethane, and neoprene. Specimens of each material were exposed to the liquid and gaseous phases of the test fuels for 4 weeks at 60 °C, and properties in the wetted and dried states were measured.more » Exposure to bio-oil produced significant volume expansion in the fluorocarbons, NBRs, and fluorosilicone; however, excessive swelling (over 80%) was only observed for the two fluorocarbons and two NBR grades. The polyurethane specimens were completely degraded by the bio-oil. In contrast, both silicone and SBR exhibited lower swelling levels in bio-oil compared to neat diesel fuel. The implication is that, while polyurethane and fluorocarbon may not be acceptable seal materials for bio-oils, silicone may offer a lower cost alternative.« less

  19. 77 FR 10373 - Greenhouse Gas Reporting Program: Electronics Manufacturing: Revisions to Heat Transfer Fluid...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-22

    ... the definition of fluorinated GHGs in subpart A explicitly exclude greases, oils, lubricants, polymers... lubricants and embedded solid polymers are not covered. The EPA is not explicitly excluding ``polymers..., fluorocarbon polymers are solids at room temperature and will not meet the definition of a fluorinated...

  20. 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)

  1. 46 CFR 130.230 - Protection from refrigerants.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 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 pressure-demand... refrigeration equipment. (c) A complete recharge in the form of a spare charge must be carried for each...

  2. 46 CFR 130.230 - Protection from refrigerants.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 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 pressure-demand... refrigeration equipment. (c) A complete recharge in the form of a spare charge must be carried for each...

  3. 46 CFR 130.230 - Protection from refrigerants.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 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 pressure-demand... refrigeration equipment. (c) A complete recharge in the form of a spare charge must be carried for each...

  4. 46 CFR 130.230 - Protection from refrigerants.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 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 pressure-demand... refrigeration equipment. (c) A complete recharge in the form of a spare charge must be carried for each...

  5. 46 CFR 130.230 - Protection from refrigerants.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 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 pressure-demand... refrigeration equipment. (c) A complete recharge in the form of a spare charge must be carried for each...

  6. Workshop on Recent Advances in Fluorinated Surfactants

    DTIC Science & Technology

    2007-11-02

    This workshop aims to explore fundamental science questions related to fluorosurfactant assemblies, including micelles, microemulsions and vesicles... fluorosurfactant solutions and self-assembly in non-aqueous media such as fluorocarbons and dense carbon dioxide; fluorosurfactants in blood...substitute formulations, oxygen and drug delivery systems; and fluorosurfactants in new coatings protocols and applications in microelectronics and patterning

  7. SYNTHETIC FIBERS, 1965,

    DTIC Science & Technology

    The following groups of fibers are each briefly discussed: Glass and other inorganic fibers, viscose rayon, cuprammonium rayon, saponified acetate rayon, alginate rayon, regenerated protein fibers, cellulose nitrate, cellulose acetate rayon, cellulose triacetate, polyamides, acrylics, modacrylics, polyvinyls, polyvinylidenes, polyesters, polyolefins, polyurethanes, fluorocarbons.

  8. 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...

  9. Hydraulic System Seal Development.

    DTIC Science & Technology

    1981-06-01

    supplying the seal. Shamban, Fluorocarbon, Parker, Powty, Hercules, Disogrin, Bal Seal Engineering, American Variseal , Tetrafluor, Conover, and Greene...characteristics, as did the Variseal , but both caused minor rod scoring. The Greene Tweed llytrel seal was not considered for further testing becduse

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Modelling small angle neutron scattering data from polymers in supercritical fluids

    NASA Astrophysics Data System (ADS)

    Triolo, F.; Triolo, A.; Lo Celso, F.; Johnson, J. S.; Donato, D. I.; Triolo, R.

    2000-04-01

    In this paper we report a SANS investigation of micelle formation by fluorocarbon-hydrocarbon block copolymers in supercritical CO2(scCO2) at 313K. A sharp unimer-micelle transition is obtained due to the tuning of the solvating ability of scCO2 by profiling pressure. At high pressure the copolymer is in a monomeric state with a random coil structure. By lowering the pressure aggregates are formed with the hydrocarbon segments forming the core and the fluorocarbon segments forming the corona of spherical aggregates. This aggregate-unimer transition is driven by the gradual penetration of CO2 molecules toward the core of the aggregate and is critically related to the density of the solvent, thus suggesting the definition of a critical micellization density (CMD).

  15. Pretreatment of Kapton-coated cable for epoxy adhesion

    NASA Astrophysics Data System (ADS)

    Carley, J. F.

    1984-01-01

    A new system to protect bonded strain gages that will be attached to the MFTF magnets was tested and indicated falling electrical resistance to ground, which is attributed to the infiltration of moisture. The most likely infiltration route seemed to be along the Kapton lead cable, which has an outer space of FEP fluorocarbon resin. The treated ends are embedded in the 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. It is shown 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. It appears that the 40-s exposure to Tetra-Etch has penetrated the 0.5 mil fluorocarbon coating and attacks the Kapton film and the conductor coatings inside it.

  16. 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.

  17. Toxic alveolitis after inhalation of a water repellent.

    PubMed

    Epping, Guido; Van Baarlen, Joop; Van Der Valk, Paul D L P M

    2011-12-01

    Inhalation of fluorocarbon polymers can cause pulmonary toxicity. Although multiple cases of lung injury have been reported, cellular characterization of the associated alveolitis occurring acutely after inhalation is limited. We report the case of a previously healthy woman who presented at our Emergency Department with an acute pneumonitis following inhalation of a fluorocarbon polymer-based rain-proofing spray. Bronchoalveolar lavage (BAL) performed shortly after the presentation showed an elevated total cell count, with a high proportion of neutrophils (58%) and eosinophils (9%). In addition, a lipid stain (Oil-Red-O-stain) showed a high level of lipid laden macrophages, a marker that could reflect a direct toxic effect of the spray on alveolar cells. The patient made a full recovery after four days of in-hospital observation with supportive care.

  18. 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.

  19. REFINING FLUORINATED COMPOUNDS

    DOEpatents

    Linch, A.L.

    1963-01-01

    This invention relates to the method of refining a liquid perfluorinated hydrocarbon oil containing fluorocarbons from 12 to 28 carbon atoms per molecule by distilling between 150 deg C and 300 deg C at 10 mm Hg absolute pressure. The perfluorinated oil is washed with a chlorinated lower aliphatic hydrocarbon, which mairtains a separate liquid phase when mixed with the oil. Impurities detrimental to the stability of the oil are extracted by the chlorinated lower aliphatic hydrocarbon. (AEC)

  20. 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.

  1. 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.

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

    NASA Astrophysics Data System (ADS)

    Ross, B.; Parker, J.

    1983-12-01

    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.

  3. 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.

  4. The Effect of Switch-Loading Fuels on Fuel-Wetted Elastomers

    DTIC Science & Technology

    2007-01-10

    material and age of the material”. In summing up past experience, the bulletin stated that “the common denominator is expected to be nitrile rubber ...The expert also noted that “most, if not all manufacturers, responded by eliminating nitrile rubber seals and replacing them with fluorocarbon...layer interfaces with the fuel at steady state is often composed of a nitrile rubber . The exterior layer of the fuel cell bladder is a nylon

  5. Applicability of Fiber Optics to Aircraft Fire Detection Systems

    DTIC Science & Technology

    1978-10-01

    in aircraft, such as elevated temperatures, chemical contamination, acoustic noise, vibration, shock, altitude and reliability/maintainability...in and fan-out techniques - and their optical, mechanical, and chemical characteristics relevant to air- craft fire detection system applications...the acceptance half-angle (0NA) of optical fibers is a property of the fibers themselves (ranging from 8’ for fluorocarbon resin clad quartz fibers that

  6. THE PREPARATION OF FLUORINE-CONTAINING COMPOUNDS

    DTIC Science & Technology

    reaction was the condensation of perfluoroalkyl amidines to form triazines. Other reactions discussed include: (1) the addition of N2H4 to perfluoroalkyl ...nitriles with production of perfluoroalkyl hydrazidines and 2,5 bis( perfluoroalkyl )1-N-amino-1,3,5-triazoles; (2) the reaction of perfluoropropene with...S to form the 1,4 dithane ring; (3) dimerization, trimerization and polymerization of unsaturated fluorocarbons; (4) synthesis of perfluoroalkyl and

  7. CERDEC Co-generation and Absorption System Targets and Enabling Technologies

    DTIC Science & Technology

    2009-05-06

    Vapor compression – low-GWP fluorocarbons and natural refrigerants – Absorption – ammonia, lithium-bromide, and other novel cycles – Adsorption ...Technologies Ph t lt i d• o ovo a c an Solar Concentrators •Wind Turbines Applications •Tactical Mobile Power •Fuel Processing, Waste-to-Energy, and...Technologies: – Novel heat exchanger geometries/materials, compressor designs, fluid handling/mixing refrigeration cycles and work recovery devices

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Visible-range hollow waveguides by guided buckling of Ta2O5/SiO2 multilayers.

    PubMed

    Melnyk, A; Potts, C A; Allen, T W; DeCorby, R G

    2016-05-01

    Hollow waveguides operating near 550 nm wavelength were fabricated by guided formation of delamination buckles within Ta2O5/SiO2 multilayers. The fabrication process employed a pair of sequentially deposited 10-period Bragg mirrors separated by a patterned, low-adhesion fluorocarbon layer. Propagation loss as low as a few dB/cm was measured, consistent with theoretical predictions.

  16. Contraband Detection with Nuclear Resonance Fluorescence: Feasibility and Impact

    SciTech Connect

    Pruet, J; Lange, D

    2007-01-03

    In this report they show that cargo interrogation systems developed to thwart trafficking of illicit nuclear materials could also be powerful tools in the larger fight against contraband smuggling. In particular, in addition to detecting special nuclear materials, cargo scanning systems that exploit nuclear resonance fluorescence to detect specific isotopes can be used to help find: chemical weapons; some drugs as well as some chemicals regulated under the controlled substances act; precious metals; materials regulated under export control laws; and commonly trafficked fluorocarbons.

  17. Evaluation of Four Well Casing Materials for Monitoring Selected Trace Level Organics in Ground Water

    DTIC Science & Technology

    1988-10-01

    than in those from Several components of rigid PVC may possibly either plastic-lined well. leach. These components include vinyl chloride At site 2, the...casing materials, polyvinyl chloride ( PVC ), Teflon, stainless steel 304 (SS 304) and stainless steel 316 (SS 316), to determine their suitability for...virgin fluorocarbon resins, i.e., fluorinated ethyl- tion (NSF) or ASTM-approved polyvinyl chloride ene propylene (FEP), polytetrafluoroethylene ( PVC

  18. Fever induced by fluorine-containing lubricant on stainless steel tubes.

    PubMed Central

    Akesson, B; Högstedt, B; Skerfving, S

    1980-01-01

    Three subjects, all smokers, handling stainless steel tubes suffered repeated attacks of general malaise, chills, and fever lasting for several hours, mainly after gas soldering. Provocations by rubbing smoking tobacco against a tube produced similar attacks, and leucocytosis, after a few hours. The presence of fluorine on the tubes and in the febrifacient tobacco was shown. A fluorocarbon polymer lubricant was suspected of causing the attacks. Heating (1000 degrees C) of the tubes eliminated the effect. PMID:7426482

  19. Materials Degradation and Fatigue Under Extreme Conditions

    DTIC Science & Technology

    1997-10-29

    molecularly-thin fluids of very different structure were contrasted: a globular molecule, branched alkanes, and a polymer brush in near-theta solution...34 A. Dhinojwala, L. Cai, and S. Granick, Langmuir 12, 4537 (1996). 28. "New Approaches to Measure Interfacial Rheology of Confined Fluids ," A...Degradation of Fluorocarbon Lubricants; Molecular Tribology of Perfluoroether Lubricants; Fluids , Including Lubricants Under Extreme Conditions of

  20. Fluorspar

    USGS Publications Warehouse

    Miller, M.

    1996-01-01

    The U.S. consumed about 525 kt of fluorspar in 1995, with more than 70 percent being used for the production of hydrofluoric acid. Fluorspar is also used for the production of aluminum and steel. About 558 kt of fluorspar was imported in 1995, with a further 186 kt made available from the National Defense Stockpile. The market in the U.S. is expected to grow as increasing use is made of fluorocarbons to replace chlorofluorocarbons.

  1. The equation of state of HF under shock compression

    SciTech Connect

    Fried, L E; Howard, W M

    1999-06-01

    We develop a model of chemical equilibrium mixtures containing the elements H, C, F. We show that the shock response of a wide variety of molecular and polymeric fluorocarbons can be modeled as a chemical equilibrium mixture of a small number of dissociation product molecules. HF is known to strongly associate in the supercritical fluid phase. We predict that such an association also occurs under shock conditions.

  2. 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

    2001-01-01

    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.

  3. The differential response of the skin in young and old rats to a combination of X-rays and 'wet' or 'dry' hyperthermia.

    PubMed

    Hamlet, R; Hopewell, J W

    1986-11-01

    The left hind feet of groups of female rats aged 7, 14 and 52 weeks were irradiated at three dose levels of X-rays (20, 25 or 30 Gy). Hyperthermia (42.5 degrees C for 1 h) was carried out immediately following irradiation using either 'wet' or 'dry' heat, achieved by immersion in either water or fluorocarbon liquid. The results demonstrated that 'wet' heat produced a consistently greater enhancement of the irradiation damage than 'dry' heat. The thermal enhancement ratio for irradiation plus 'wet' heat was approximately 1.5 and for irradiation plus 'dry' heat it was in the range 1.17 to 1.39. Immersion of the feet in fluorocarbon liquid at 37 degrees C did not significantly modify the irradiation response of the skin. The lower thermal enhancement ratios obtained using immersion in fluorocarbon liquid at 42.5 degrees C are close to those obtained in large animal studies and also similar to the limited amount of data from clinical studies where microwave or ultrasound heating techniques were used. It has been demonstrated that there are large age-related differences in the response of the rat foot skin to irradiation alone. It has also been shown in the present study, using rats of the same age, that the response to irradiation plus hyperthermia was less age dependent. This finding may reflect the differing methods by which damage occurs in tissue after irradiation or hyperthermia.

  4. Proposal to produce novel, transparent radiation hard low refractive index polymers. Final report, 1 October-31 December 1993

    SciTech Connect

    Schuman, P.D.; Harmon, J.

    1994-02-09

    Low and high molecular weight polymers of heptafluorobutyl methacrylate, HFBM, were prepared for commercial evaluation by Bicron, an optical fiber manufacturer. Polymers were evaluated as low refractive index fiber cladding materials. Test results of Low MW polymer solutions gave excellent results. Higher MW polymers were prepared for cladding by melt co-extrusion. Corning Glass Corp, also expressed an interest in these cladding materials. These results appear to be sufficiently unique that a search has been initiated to determine patentability of the soluble fluorocarbon acrylate, methacrylate and copolymer compositions for cladding use. This research resulted in identifying a radiation hard, low refractive index polymer, poly(heptafluorobutyl methacrylate), P(HFBM) as the best candidate for a novel cladding material. P(HFBM) has a refractive index of 1.387. When used to clad a styrene core, the theoretical light propagation efficiency is 50% greater than that of styrene fiber core clad with PMMA, a common commercial cladding material. These polymers will be the only commercial fluorocarbon acrylic cladding polymers available to U.S. manufacturers. Japanese optical fiber manufacturers produce fluorocarbon clad fibers but their polymers are not available to U.S. manufacturers. These polymers can fill an urgent need in the optical fiber market.

  5. Surface-segregated monolayers: a new type of ordered monolayer for surface modification of organic semiconductors.

    PubMed

    Wei, Qingshuo; Tajima, Keisuke; Tong, Yujin; Ye, Shen; Hashimoto, Kazuhito

    2009-12-09

    We report a new type of ordered monolayer for the surface modification of organic semiconductors. Fullerene derivatives with fluorocarbon chains ([6,6]-phenyl-C(61)-buryric acid 1H,1H-perfluoro-1-alkyl ester or FC(n)) spontaneously segregated as a monolayer on the surface of a [6,6]-phenyl-C(61)-butyric acid methyl ester (PCBM) film during a spin-coating process from the mixture solutions, as confirmed by X-ray photoelectron spectroscopy (XPS). Ultraviolet photoelectron spectroscopy (UPS) showed the shift of ionization potentials (IPs) depending on the fluorocarbon chain length, indicating the formation of surface dipole moments. Surface-sensitive vibrational spectroscopy, sum frequency generation (SFG) revealed the ordered molecular orientations of the C(60) moiety in the surface FC(n) layers. The intensity of the SFG signals from FC(n) on the surface showed a clear odd-even effect when the length of the fluorocarbon chain was changed. This new concept of the surface-segregated monolayer provides a facile and versatile approach to modifying the surface of organic semiconductors and is applicable to various organic optoelectronic devices.

  6. Nanoparticles Formed by Acoustic Destruction of Microbubbles and Their Utilization for Imaging and Effects on Therapy by High Intensity Focused Ultrasound

    PubMed Central

    Blum, Nicholas T.; Yildirim, Adem; Chattaraj, Rajarshi; Goodwin, Andrew P.

    2017-01-01

    This work reports that when PEG-lipid-shelled microbubbles with fluorocarbon interior (C4F10, C5F12, or C6F14) are subjected to ultrasound pulses, they produce metastable, fluid-filled nanoparticles that can be re-imaged upon administration of HIFU. The nanoparticles produced by destruction of the microbubbles (MBNPs) are of 150 nm average diameter and can be re-imaged for up to an hour after creation for C 4F10, and for at least one day for C5F12. The active species were found to be fluid (gas or liquid) filled nanoparticles rather than lipid debris. The acoustic droplet vaporization threshold of the nanoparticles was found to vary with the vapor pressure of the encapsulated fluorocarbon, and integrated image brightness was found to increase dramatically when the temperature was raised above the normal boiling point of the fluorocarbon. Finally, the vaporization threshold decreases in serum as compared to buffer, and administration of HIFU to the nanoparticles caused breast cancer cells to completely detach from their culture substrate. This work demonstrates a new functionality of microbubbles that could serve as a platform technology for ultrasound-based theranostics. PMID:28255360

  7. 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.

  8. 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.

  9. Plasma polymerization for cell adhesive/anti-adhesive implant coating

    NASA Astrophysics Data System (ADS)

    Meichsner, Juergen; Testrich, Holger; Rebl, Henrike; Nebe, Barbara

    2015-09-01

    Plasma polymerization of ethylenediamine (C2H8N2, EDA) and perfluoropropane (C3F8, PFP) with admixture of argon and hydrogen, respectively, was studied using an asymmetric 13.56 MHz CCP. The analysis of the plasma chemical gas phase processes for stable molecules revealed consecutive reactions: C2H8N2 consumption, intermediate product NH3, and main final product HCN. In C3F8- H2 plasma the precursor molecule C3F8 and molecular hydrogen are consumed and HF as well as CF4 and C2F6 are found as main gaseous reaction products. The deposited plasma polymer films on the powered electrode are strongly cross-linked due to ion bombardment. The stable plasma polymerized films from EDA are characterized by high content of nitrogen with N/C ratio of about 0.35. The plasma polymerized fluorocarbon film exhibit a reduced F/C ratio of about 1.2. Adhesion tests with human osteoblast cell line MG-63 on coated Ti6Al4V samples (polished) compared with uncoated reference sample yielded both, the enhanced cell adhesion for plasma polymerized EDA and significantly reduced cell adhesion for fluorocarbon coating, respectively. Aging of the plasma polymerized EDA film, in particular due to the reactions with oxygen from air, showed no significant change in the cell adhesion. The fluorocarbon coating with low cell adhesion is of interest for temporary implants. Funded by the Campus PlasmaMed.

  10. 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 dm–3 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 2–4 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.

  11. Thermal desorption mass spectrometric and x-ray photoelectron studies of etched surfaces of polytetrafluoroethylene

    NASA Astrophysics Data System (ADS)

    Rye, R. R.; Kelber, J. A.

    1987-12-01

    The etching of polytetrafluoroethylene (PTFE) with Na solutions is known to lead to a loss of F, a loss which is correlated with enhanced adhesion. Subsequent heating partially restores surface F with a concurrent loss of adhesion strength. We have combined X-ray photoelectron spectroscopy (XPS) and gas phase mass spectroscopy for in situ measurements of the processes that occur as the fluorocarbon is heated. An array of volatile products, which vary with the specific treatment, desorb from etched PTFE. Among these are: N 2 and low molecular weight fluorocarbons, the amounts of which monotonically decrease with increasing exposure to the etching solution (and probably result from the bulk); species such as CO and CO 2, which in part result from surface impurities; and water and acetone which result from the rinse steps following the etching process. XPS measurements show that etching produces a major loss of surface F and a gain of surface O. The latter probably results from the subsequent rinse steps. Heating produces a substantial recovery in surface F with only a small decrease in the surface O, and the gain in surface F is shown to occur at a higher temperature than the desorption of any species from the surface. Thus, desorption of products from the surface is decoupled, in terms of both the distribution of products and their relative temperatures, from the surface changes as monitored by XPS. This decoupling suggests that the increase in surface F results from diffusion of low molecular weight fluorocarbons from the bulk or a transition region, or from a rearrangement of the sponge-like surface region produced in the etching process.

  12. Building blocks for n-type molecular and polymeric electronics. Perfluoroalkyl- versus alkyl-functionalized oligothiophenes (nT; n = 2-6). Systematics of thin film microstructure, semiconductor performance, and modeling of majority charge injection in field-effect transistors.

    PubMed

    Facchetti, Antonio; Mushrush, Melissa; Yoon, Myung-Han; Hutchison, Geoffrey R; Ratner, Mark A; Marks, Tobin J

    2004-10-27

    The solid-state properties and FET electrical behavior of several series of alpha,omega- and beta,beta'-fluorocarbon- and alkyl-substituted and unsubstituted oligothiophenes nTs (n = 2-6) are compared and contrasted. The thin films were grown by slow vacuum deposition over a range of substrate temperatures and/or by casting from solution and were investigated by X-ray diffraction and scanning electron microscopy. Our results indicate that vacuum deposition at 60-80 degrees C affords films with remarkably similar microstructures despite the extensive H --> F substitution. Trends in observed d spacing versus molecular core extension provide quantitative information on molecular orientation. Field-effect transistor measurements performed for all systems and having the same device structure, components, and fabrication conditions demonstrate that all nTs functionalized with fluorocarbon chains at the thiophene termini are n-type semiconductors, in contrast to the p-type activity of the remaining systems. One of these systems, alpha,omega-diperfluorohexyl-4T, exhibits a mobility of 0.22 cm2/(V s) and an Ion:Ioff ratio of 10(6), one of the highest so far reported for an n-type organic semiconductor. The effect of substitution regiochemistry on FET majority charge carrier was additionally studied, in the case of a 6T core, by shifting the fluorocarbon substituents from the terminal to the central thiophene units. Finally, we propose a simple theoretical model for electrode/organic interfacial carrier injection. The results suggest why modest substituent-induced changes in the injection barrier can produce working n-type materials.

  13. 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.

  14. 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.

  15. Elaboration of composite and chemically heterogeneous icephobic coatings

    NASA Astrophysics Data System (ADS)

    Arianpour, Faranak

    Atmospheric icing happens when the surfaces of exposed structures are subjected to contact with super-cooled water droplets or snow particles. Ice build-up on overhead transmission and distribution lines may lead to mechanical failure or insulator flashover, sometimes resulting in power outages with major socioeconomic consequences. The present study focused on the preparation of heterogeneous coatings (HCs) with hydro- and icephobic properties presenting a number of advantages, such as easy application, time-saving and low cost. The homo- and HCs were prepared by using different methods such as self-assembly, nanoparticles-based and Plasma-based techniques. Super-hydrophobic coatings with very low wetting hysteresis are also considered to be icephobic. However, even super-hydrophobic coatings can deteriorate during successive icing/de-icing cycles, and this can lead to ice mechanical anchoring since liquid water penetrates the porous surface. Additionally, the cost and complexity involved in the fabrication of such coatings as micro and nano roughness is created, constitute other hurdles. In this study HCs are considered as a coating including hydrocarbons and fluorocarbons, while purely hydrocarbons or fluorocarbons coatings are considered as the homogeneous coatings. It was shown by applying different functions (both C-F and C-H) the surface energy is decreased more compared to applying only one function (C-F or C-H alone). It should be noted that the water molecule orientations at the surfaces of the fluorocarbon and hydrocarbon groups were completely different. As a result, by inducing or creating various disparities (hydrocarbons and fluorocarbons) in terms of energy bonding, and water molecule orientation at the molecular level, the ice-solid interface is weakened. The wettability measurement of the HCs showed higher water contact angle (CA) values and smaller water contact angle hysteresis (CAH) values compared to homogeneous coatings. The most important

  16. Chlorofluorocarbon CFCs, potential alternative HCFCs and HFCs, and related chlorinated compounds: mass spectral study, Part II.

    PubMed

    Reizian-Fouley, A; Dat, Y; Rault, S

    1997-04-01

    In a previous publication, mass spectrometry was applied to the study of several ions formed by dissociative ionization of ethanes, partially substituted with fluorine and chlorine, and to the determination of the fragmentation pattern of each related compound. The aim of the present investigation was to extend this mass spectral study (70 eV and low ionization energy) to a group of closely related analogs, hydrofluorocarbons (HCFCs), HFCs, chlorinated fluorocarbons, and chlorinated hydrocarbons--halogenated methane, ethane, and propane molecules--to make an attempt to predict the relative bond strength and then the behavior--metabolic pathway and tropospheric degradation--of new HCFCs and HFCs.

  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. 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

  19. 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.

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

    DOEpatents

    Martinez, Robert J.; Rye, Robert R.

    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.

  1. 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.

  2. Optically pumped far-infrared lasers

    NASA Astrophysics Data System (ADS)

    Button, K. J.; Inguscio, M.; Strumia, F.

    A handbook of far-infrared (submillimeter) laser technology is presented. Among the specific laser systems described are: 12CH3F and 13CH3F lasers; submillimeter lasers in dueuterated methyl fluoride CD3F; and far-infrared laser lines obtained by optical pumping. Consideration is given to other far-infrared laser media, including: methyl iodide; CH3OH; D2O; and fluorocarbon 12, CF2C12. Additional topics discussed include: an optically pumped PH3 laser operating in the region 83-223 microns; an optically pumped formic acid laser; and optically pumped infrared lasing in propyne.

  3. Weak-value thermostat with 0.2 mK precision.

    PubMed

    Egan, Patrick; Stone, Jack A

    2012-12-01

    A new laser-based thermostat sensitive to 0.2 mK at room temperature is reported. The method utilizes a fluid-filled prism and interferometric weak-value amplification to sense nanoradian deviations of a laser beam: due to the high thermo-optic coefficient of the fluid (colorless fluorocarbon), the deviation angle through the prism is sensitive to temperature. We estimate the daily stability of our device to be 0.2 mK, which is limited by drifts in the apparatus, and the narrow 20 mK capture range is the price paid for the weak measurement.

  4. Feasibility study of a cryogenically cooled window for high-power gyrotrons

    SciTech Connect

    Haste, G.R.; Kimrey, H.D.; Prosise, J.D.

    1986-07-01

    Single-crystal sapphire is currently in use as the material for output windows in high-power microwave tubes, particularly gyrotrons. These windows are currently being cooled by fluorocarbon fluids at near-room temperatures. There are, however, several advantages in operating the window at very low temperatures: less absorption and consequent heating of the window, greater material strength, improved resistance to crack formation, greater thermal conductivity, and reduced thermal expansion. Operation at cryogenic temperatures is shown to be feasible. The output power, which is currently limited by window constraints, could be increased by an order of magnitude or more.

  5. 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.

  6. Low-cost encapsulation materials for terrestrial solar cell modules

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

    The paper presents the findings of material surveys intended to identify low cost materials which could be functional as encapsulants (by 1986) for terrestrial solar cell modules. Economic analyses have indicated that in order to meet the low cost goal of $2.70 per sq m, some or all of the following material technologies must be developed or advanced: (1) UV screening outer covers; (2) elastomeric acrylics; (3) weatherproofing and waterproofing of structural wood and paper products; (4) transparent UV stabilizers for the UV-sensitive transparent pottants; and (5) cost-effective utilization of silicone and fluorocarbon materials.

  7. Diamond Growth on Carbide Surfaces Using a Selective Etching Technique

    DTIC Science & Technology

    1993-07-01

    nucleation when utilizing hexafluoroethane (C2F6 ) (b), perfluoropropane ( C3F8 ) (c), and octafluorocyclobutane (C4F8 ) (d). Carbon-fluorine atomic ratios...and roughen WC particles SiC: No modification Feed Gases: CF 4, C2F6, C3F8 , or C4F8 all at 1/2% - 3%, 1% 02, balance H2 Total Flow Rate: 200 sccm...1/2% CF 4, (b) 1/2% C2F6, (c) 1/2% C3F8 , and (d) 1/2% C4F8. Figure 6. Growth of diamond on tungsten carbide / 6% cobalt using various fluorocarbon

  8. Solubilities of krypton and xenon in dichlorodifluoromethane

    SciTech Connect

    Shaffer, J.H.; Shockley, W.E.; Greene, C.W.

    1984-07-01

    The solubility behavior of krypton and xenon in dichlorodifluoromethane was investigated for the Consolidated Fuel Reprocessing Program (CFRP) in support of the fluorocarbon absorption process. The solubility data derived from solute radioisotopes had uncertainties of approx. 0.1%. Values for Henry's law constants were initially determined under equilibrium conditions at infinite solute dilution. Based on these results, the study was extended to finite solute concentrations. Nonidealities in the two binary systems were expressed as gas phase fugacity coefficients for each solute at 10/sup 0/ intervals over the range -30 to +50/sup 0/C. 22 references, 4 figures, 2 tables.

  9. Effective Disposal of Fuel Cell Polyurethane Foam

    DTIC Science & Technology

    1987-01-01

    June 1986, EPA announced proposed changes to the EP Toxicity Test. A new test, known as the Toxicity Characteristic Leaching Procedure ( TCLP ), W...benzene and toluene under the TCLP are 0.07 mg/L and 14.4 mg/L, respectively. A modified TCLP Test was performed at the AFESC on samples of...functional group with water to give carbon dioxide gas (a technique employed by SCOTFOAM) or by addition of a 3 fluorocarbon blowing agent. Dyes are added to

  10. 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.

  11. 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.

  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. 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.

  14. Inhibition of bacterial and leukocyte adhesion under shear stress conditions by material surface chemistry.

    PubMed

    Patel, Jasmine D; Ebert, Michael; Stokes, Ken; Ward, Robert; Anderson, James M

    2003-01-01

    Biomaterial-centered infections, initiated by bacterial adhesion, persist due to a compromised host immune response. Altering implant materials with surface modifying endgroups (SMEs) may enhance their biocompatibility by reducing bacterial and inflammatory cell adhesion. A rotating disc model, which generates shear stress within physiological ranges, was used to characterize adhesion of leukocytes and Staphylococcus epidermidis on polycarbonate-urethanes and polyetherurethanes modified with SMEs (polyethylene oxide, fluorocarbon and dimethylsiloxane) under dynamic flow conditions. Bacterial adhesion in the absence of serum was found to be mediated by shear stress and surface chemistry, with reduced adhesion exhibited on materials modified with polydimethylsiloxane and polyethylene oxide SMEs. In contrast, bacterial adhesion was enhanced on materials modified with fluorocarbon SMEs. In the presence of serum, bacterial adhesion was primarily neither material nor shear dependent. However, bacterial adhesion in serum was significantly reduced to < or = 10% compared to adhesion in serum-free media. Leukocyte adhesion in serum exhibited a shear dependency with increased adhesion occurring in regions exposed to lower shear-stress levels of < or = 7 dyne/cm2. Additionally, polydimethylsiloxane and polyethylene oxide SMEs reduced leukocyte adhesion on polyether-urethanes. In conclusion, these results suggest that surface chemistry and shear stress can mediate bacterial and cellular adhesion. Furthermore, materials modified with polyethylene oxide SMEs are capable of inhibiting bacterial adhesion, consequently minimizing the probability of biomaterial-centered infections.

  15. Interfacial Polymerization on Dynamic Complex Colloids: Creating Stabilized Janus Droplets.

    PubMed

    He, Yuan; Savagatrup, Suchol; Zarzar, Lauren D; Swager, Timothy M

    2017-03-01

    Complex emulsions, including Janus droplets, are becoming increasingly important in pharmaceuticals and medical diagnostics, the fabrication of microcapsules for drug delivery, chemical sensing, E-paper display technologies, and optics. Because fluid Janus droplets are often sensitive to external perturbation, such as unexpected changes in the concentration of the surfactants or surface-active biomolecules in the environment, stabilizing their morphology is critical for many real-world applications. To endow Janus droplets with resistance to external chemical perturbations, we demonstrate a general and robust method of creating polymeric hemispherical shells via interfacial free-radical polymerization on the Janus droplets. The polymeric hemispherical shells were characterized by optical and fluorescence microscopy, scanning electron microscopy, and confocal laser scanning microscopy. By comparing phase diagrams of a regular Janus droplet and a Janus droplet with the hemispherical shell, we show that the formation of the hemispherical shell nearly doubles the range of the Janus morphology and maintains the Janus morphology upon a certain degree of external perturbation (e.g., adding hydrocarbon-water or fluorocarbon-water surfactants). We attribute the increased stability of the Janus droplets to (1) the surfactant nature of polymeric shell formed and (2) increase in interfacial tension between hydrocarbon and fluorocarbon due to polymer shell formation. This finding opens the door of utilizing these stabilized Janus droplets in a demanding environment.

  16. Micromachining of optically transparent materials by laser ablation of a solution containing pyrene

    NASA Astrophysics Data System (ADS)

    Yabe, Akira; Niino, Hiroyuki; Wang, Jun

    2001-01-01

    Optically transparent materials such as fused silica, quartz crystal, calcium fluoride, and fluorocarbon polymer were etched upon irradiation of organic solution containing pyrene with a conventional KrF or XeCl excimer laser. Threshold fluences for etching were 240 mJ/cm2 for fused silica, 330 mJ/cm2 for quartz crystal, 740 mJ/cm2 for calcium fluoride, and 45 mJ/cm2 for fluorocarbon polymer. These threshold values were remarkably low compared with those of direct ablation by using conventional lasers. Their etch rates remarkably depended on a concentration of pyrene: the etch rate became higher as the pyrene concentration increased. It means that pyrene molecules play an important role in this process. The mechanisms for this process is discussed by cyclic multiphotonic absorption of pyrene in the excited states, thermal relaxation, and formation of super-heated solution. As the results suggest, the process is based on the combination of two physical processes in the interface between the transparent materials and the liquid: one is a heating process by a super-heated liquid and the other is an attacking process by a high temperature and pressure vapor. The mechanism is also referred to thermal properties of materials.

  17. 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.

  18. Characterization of radical production mechanism in CHF3 and CF4 inductively coupled plasmas

    NASA Astrophysics Data System (ADS)

    Wang, Yaping; Zhao, Shuxia; PSEG Team

    2015-09-01

    Inductively coupled fluorocarbon (fc) plasmas are widely used in Si /SiO2 etching industry as they provide active radicals which are reactive to the Si or SiO2 materials. It is well known that CHF3 plasma has relatively low density ratio of F vs. CFx radicals and hence high etching selectivity, as compared with the CF4 , due to the fact that one F is replaced by H in CHF3 molecules and H can abstract F from fluorocarbon radicals to form HF. However, for now, much elaborate details are still missed in the literature. Therefore in this work, a fluid model is used to characterize the radical production components in these two different fc plasmas. The fluid model includes continuity and energy equations for electrons, continuity and momentum equations for ions and continuity equations for radicals. An electromagnetic model is used to calculate the electric field which is generate by coupling coil current and Poisson equation is used to calculate the static field within the plasma. The model predicts the electron density, ion density and radical density of CHF3 plasma. For now the simulations of CF4 plasma are still under construction. We expect to compare the different radical production mechanisms in the CHF3 and CF4 plasma sources in new future.

  19. Assessment of Public Perception of Greenhouse Gases as Precursor to Climate Change Mitigation in Nigeria

    NASA Astrophysics Data System (ADS)

    Nwankwo, L.

    2013-12-01

    The rising concentrations of both CO2 and Non-CO2 Greenhouse Gases in the earth's atmosphere are leading to global climate change. The need to address this climate change has gained momentum in recent times, and as a result public awareness of such greenhouse gases serves as a precursor to climatic change mitigation strategy. Therefore, this study entails collection of information about public perception of Climate Change and identification of carbon dioxide, methane, fluorocarbons, and aerosols as contributors to climate forcing. The assessment was completed using conventional survey technique applied amid 1000 people in Ilorin metropolis, Nigeria. The results show 34.9%, 23.6%, 4.5%, 12.3% and 0.2% levels of recognition or understanding of climate change, carbon dioxide, methane, fluorocarbons and aerosols respectively. The results reveal that public awareness of climate change is low in the study area, while Non-CO2 Greenhouse Gases as contributor to Climate Change is extremely low compared to CO2. The study is a preliminary effort to elicit public views and therefore, would assist decision makers and enhance communication with the public in the context of Science and Environment Policy.

  20. 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.

  1. From superamphiphobic to amphiphilic polymeric surfaces with ordered hierarchical roughness fabricated with colloidal lithography and plasma nanotexturing.

    PubMed

    Ellinas, K; Tserepi, A; Gogolides, E

    2011-04-05

    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).

  2. 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.

  3. 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.

  4. 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.

  5. Low-noise polymeric nanomechanical biosensors

    NASA Astrophysics Data System (ADS)

    Calleja, Montserrat; Tamayo, Javier; Nordström, 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.

  6. 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.

  7. 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.

  8. Nafion-Modified PEDOT:PSS as a Transparent Hole-Transporting Layer for High-Performance Crystalline-Si/Organic Heterojunction Solar Cells with Improved Light Soaking Stability.

    PubMed

    Hossain, Jaker; Liu, Qiming; Miura, Takuya; Kasahara, Koji; Harada, Daisuke; Ishikawa, Ryo; Ueno, Keiji; Shirai, Hajime

    2016-11-23

    We demonstrate the chemistry of amphiphilic perfluorosulfonic copolymer Nafion-coated conductive poly(3,4-ethyelenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and its effect on the photovoltaic performance of PEDOT:PSS/crystalline Si (c-Si) heterojunction solar cells. The highly hydrophilic sulfonate group of insulating, chemically stable Nafion interacts with PSS in PEDOT:PSS, which reduce the Coulombic interaction between PEDOT and PSS. The highly hydrophobic fluorocarbon backbone of Nafion favorably interacts with hydrophobic PEDOT of PEDOT:PSS. These factors give rise to the extension of π-conjugation of PEDOT chains. Silver paste used as a top grid electrode diffused into the Nafion layer and contacted with underneath Nafion-modified PEDOT:PSS layer. As a consequent, solution-processed Nafion-coated PEDOT:PSS/c-Si heterojunction solar cells exhibited a higher power conversion efficiency of 14.0% with better stability for light soaking rather than that of the pristine PEDOT:PSS/c-Si device by adjusting the layer thickness of Nafion. These findings originate from the chemical stability of hydrophobic fluorocarbon backbone of Nafion, diffusivity of silver paste into Nafion and contact with PEDOT:PSS, and Nafion as an antireflection layer.

  9. Comparative Studies of Perfluorocarbon Alternative Gas Plasmas for Contact Hole Etch

    NASA Astrophysics Data System (ADS)

    Nakamura, Shingo; Itano, Mitsushi; Aoyama, Hirokazu; Shibahara, Kentaro; Yokoyama, Shin; Hirose, Masataka

    2003-09-01

    Saturated perfluorocarbons (PFCs) such as CF4, C2F6, C3F8 and c-C4F8 are used as dry-etch gases in the semiconductor industry. They have a significant greenhouse effect. Unsaturated fluorocarbons can be alternated with these PFCs because of their easy decomposition in the atmosphere. The authors have diagnosed the plasmas generated from straight-chain unsaturated gases such as C3F6, C4F6, C4F8 and C5F8 in an inductively coupled plasma reactor and have compared their etch properties. It was found that high selectivity has been obtained in a C4F6 or C5F8 plasma without mixing any specific gases. Fine contact holes of approximately 100 nm in diameter also have been obtained using C4F6 or C5F8 with or without adding Ar or O2. These good etch properties of C4F6 and C5F8 have been achieved as a consequence of the appropriate balance between the lower density of fluorocarbon polymers and the dominant etching species CF+ with lower etching efficiency. It can be concluded that C4F6 and C5F8 can be used as PFC replacements for the dry-etch gas.

  10. Time resolved QCLAS measurements in pulsed cc-rf CF4/H2 plasmas

    NASA Astrophysics Data System (ADS)

    Stepanov, S.; Welzel, S.; Röpcke, J.; Meichsner, J.

    2009-03-01

    Fluorocarbon containing capacitively coupled radio frequency (cc-rf) plasmas are widely used in technical applications and as model systems for fundamental investigations of complex plasmas. Absorption spectroscopy based on pulsed quantum cascade lasers (QCL) was applied in the mid-IR spectral range of 1269-1275 cm-1. Absolute densities of the precursor molecule CF4 and of the stable product C3F8 were measured with a time resolution of up to 1 ms in pulsed CF4/H2 asymmetrical cc-rf (13.56 MHz) discharges. For this purpose both the non-negligible temperature dependence of the absorption coefficients and the interference of the absorption features of CF4 and C3F8 had to be taken into account in the target spectral range. Therefore, at two different spectral positions composite absorption spectra were acquired under the same plasma conditions in order to discriminate between CF4 and C3F8 contributions. A total consumption of~ 12 % was observed for CF4 during a 1 s plasma pulse, whereas C3F8 appeared to be produced mainly from amorphous fluorocarbon layers deposited at the reactor walls. A gas temperature increase by ~ 100 K in the plasma pulse was estimated from the measurements. Additionally, not yet identified unresolved absorption (potentially from the excited CF4 molecule) was found during the àon-phase'.

  11. 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.

  12. 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.

  13. 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.

  14. Present-day status of investigations of anthropogenic influence on atmospheric ozone

    NASA Astrophysics Data System (ADS)

    Kondratyev, K. Y.

    1984-05-01

    The present day status of research on global spatial-temporal variability of the total content of atmospheric ozone is described. There is still a probable risk of weakening of the ozone layer as a result of the discharge of fluorocarbons, although in the future attention must also be given to other halogenated compounds which may reach the stratosphere. Should the discharge of fluorocarbons continue at the present rate, this should eventually lead to a decrease in the total ozone content by approximately 10%. For the time being there are no anthropogenically caused changes in the total ozone content. Numerical modeling indicates the existence of latitudinal and seasonal variations which must be taken into account in estimates of the consequences of a decrease in ozone content for man's health and the environment. There is a need for continuing and expanding programs for investigating all the main aspects of the problem, including numerical modeling, long-term global monitoring and laboratory measurements. A priority item is the monitoring of the ozone concentration at altitudes greater than 35 km where it is most responsive to anthropogenic effects.

  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. 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

  17. Chemical modification of sputtered amorphous-carbon surfaces

    NASA Astrophysics Data System (ADS)

    Leezenberg, Pieter B.; Johnston, William H.; Tyndall, George W.

    2001-03-01

    Methods to chemically passivate the surfaces of amorphous-carbon films (a-C) produced by dc magnetron sputtering were studied. The chemical composition of carbon surfaces produced via sputtering are dependent upon the environment to which the carbon is exposed immediately following deposition. When the sputtered film is vented to ambient conditions, free radicals produced at the surface during the deposition process are quenched by reaction with oxygen and/or water to form an oxidized, hydrophilic surface. If the sputtered carbon film is, however, exposed to a reactive gas prior to venting to ambient, the chemical nature of the resulting surface can be modified substantially. Specifically, a less highly oxidized and much more hydrophobic carbon surface is produced when the surface free radicals are quenched via either an addition reaction (demonstrated with a fluorinated olefin) or a hydrogen abstraction reaction (demonstrated with two alkyl amines). Chemical modification of amorphous-carbon films can also be accomplished by performing the sputtering in a reactive plasma formed from mixtures of argon with molecular hydrogen, amines, and perfluorocarbons. The elemental composition of these films, and the relative reactivity of the surfaces formed, were investigated via x-ray photoelectron spectroscopy and contact-angle goniometry, respectively. In the case of sputtering with a mixture of argon and hydrogen, increasing the hydrogen flow results in an increase in the amount of hydrogen incorporated into the carbon film and a decrease in the surface free energy. Sputtering in diethylamine produces an amorphous-carbon film into which nitrogen is incorporated. The free energies of the a-C:N surfaces produced in this process are similar to those of the a-C:H films. Sputtering in a fluorocarbon vapor results in the incorporation of fluorine into the film structure and the formation of very low free-energy surfaces. Increasing the concentration of the fluorocarbon in the

  18. [Artificial blood in 1990: from a lifelong dream to today's reality].

    PubMed

    Vigneron, C

    1990-10-01

    Human blood is a very complex tissue. Therefore the idea of rediscovery its different cellular and plasmatic constituents would seem to be utopic. To be efficient the oxygen carrier, be it natural or by synthesis, must be stripped of antigenicity, be easily stockable and transportable. Thus these properties permit its use in urgent circumstances (accidents, natural disasters, war...), in those countries where there is a non existent or limited transfusional structure. This, under certain conditions, during very specific pathologies (localised ischemia for example). Among several hypotheses, they are two main lines of research that of "hemoglobin solutions" the oldest and the most physiological. This will be developed here in more lengthy terms due to our personal work on the subject. The second line of research concerns fluorocarbons, the most modern and artificial and without doubt better known to doctors and the public. 1. HEMOGLOBIN SOLUTIONS. Other than nephrotoxicity, which has proved affordable, research han revealed four large limitations with hemoglobin solutions (a high affinity for oxygen due to absence or loss of 2.3 DPG, a short half life due to vascular loss, rapid dimerisation and elimination of urine, insufficient concentration of prepared solutions (70 g/L) with as a result a weak oncotic pressure and oxygen supply, oxidation in methemoglobin). In order to overcome the two inconveniences, proposals were made to modify hemoglobin chemically, the idea coming from the putting into operation of potential analogues to or substitutes for 2.3 DPG which it is advisable to bring or to keep--by covalent bonding--near to the fixation site of the natural ligand. Thus our group has already deposed several patents and is now working on a complex hemoglobin-dextran benzine tetracarboxylate which appears promising. Today, due to the quality and reproduction of the results obtained on animals with chemically modified hemoglobin preparations clinical assays should be

  19. 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.

  20. Effects of Charge Build-up of Underlying Layer by High Aspect Ratio Etching

    NASA Astrophysics Data System (ADS)

    Yonekura, Kazumasa; Kiritani, Masahide; Sakamori, Shigenori; Yokoi, Takahiro; Fujiwara, Nobuo; Miyatake, Hiroshi

    1998-04-01

    The effects of the “electron shading” charge build-up at the bottom of holes are investigated using fluorocarbon gas plasma. The etch rates of the electrically conductive films such as phosphorus-doped polysilicon at the bottom of the holes change depending on whether the films are patterned or not. This is caused by the decrease of the low-energy ions which reach the bottom of the holes due to positive charging of the underlying layers. Furthermore, the potential at the bottom of the contact holes is investigated using metal-nitride-oxide-silicon (MNOS) capacitors. The positive charging due to the electron shading effect is measured. In order to reduce the electron shading charge build-up, the pulse-modulated plasma is investigated. The selectivity to the underlying layer increases upon using pulse-modulated plasma.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Energy from ocean thermal gradients

    NASA Astrophysics Data System (ADS)

    Cohen, R.

    1980-02-01

    Ocean Thermal Energy Conversion (OTEC) transforms the solar heating of the ocean surface into electrical energy, either transmitting it to shore or using it to manufacture energy-intensive products such as aluminum, ammonia, hydrogen or magnesium at sea. Open-cycle systems, requiring extremely large turbines and degasifiers, are not thought to be as advanced as closed-cycle systems which use heat exchangers (either shell-and-tube or plate) that are made of titanium, stainless steel or aluminum alloys, which must minimize corrosion and biofouling, and that use ammonia, propane or fluorocarbons as working fluids. OTEC platform configurations include ship shapes and submersibles, such as spar buoys, and require cold-water pipes 1,000 m long, made of such materials as elastomers, lightweight concrete and fiberglass-reinforced plastic.

  7. Inspection of small multi-layered plastic tubing during extrusion, using low-energy X-ray beams

    NASA Astrophysics Data System (ADS)

    Armentrout, C.; Basinger, T.; Beyer, J.; Colesa, B.; Olsztyn, P.; Smith, K.; Strandberg, C.; Sullivan, D.; Thomson, J.

    1999-02-01

    The automotive industry uses nylon tubing with a thin ETFE (ethylene-tetrafluroethylene) inner layer to carry fuel from the tank to the engine. This fluorocarbon inner barrier layer is important to reduce the migration of hydrocarbons into the environment. Pilot Industries has developed a series of real-time inspection stations for dimensional measurements and flaw detection during the extrusion of this tubing. These stations are named LERA TM (low-energy radioscopic analysis), use a low energy X-ray source, a special high-resolution image converter and intensifier (ICI) stage, image capture hardware, a personal computer, and software that was specially designed to meet this task. Each LERA TM station operates up to 20 h a day, 6 days a week and nearly every week of the year. The tubing walls are 1-2 mm thick and the outer layer is nylon and the inner 0.2 mm thick layer is ethylene-tetrafluroethylene.

  8. Reconfigurable and responsive droplet-based compound micro-lenses

    NASA Astrophysics Data System (ADS)

    Nagelberg, Sara; Zarzar, Lauren D.; Nicolas, Natalie; Subramanian, Kaushikaram; Kalow, Julia A.; Sresht, Vishnu; Blankschtein, Daniel; Barbastathis, George; Kreysing, Moritz; Swager, Timothy M.; Kolle, Mathias

    2017-03-01

    Micro-scale optical components play a crucial role in imaging and display technology, biosensing, beam shaping, optical switching, wavefront-analysis, and device miniaturization. Herein, we demonstrate liquid compound micro-lenses with dynamically tunable focal lengths. We employ bi-phase emulsion droplets fabricated from immiscible hydrocarbon and fluorocarbon liquids to form responsive micro-lenses that can be reconfigured to focus or scatter light, form real or virtual images, and display variable focal lengths. Experimental demonstrations of dynamic refractive control are complemented by theoretical analysis and wave-optical modelling. Additionally, we provide evidence of the micro-lenses' functionality for two potential applications--integral micro-scale imaging devices and light field display technology--thereby demonstrating both the fundamental characteristics and the promising opportunities for fluid-based dynamic refractive micro-scale compound lenses.

  9. 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.

  10. 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.

  11. Improvement of the self-cleaning capabilities and transparency of cover glasses for solar cell applications by modification with atmospheric pressure plasma

    NASA Astrophysics Data System (ADS)

    Han, Duksun; Ahn, Seoung Kyu; Park, Sangho; Moon, Se Youn

    2016-07-01

    Using a cover glass is indispensable for protecting solar cells in photovoltaic systems. Herein, the surface of the cover glass was modified by atmospheric pressure plasma to enhance the self-cleaning effect without degrading the transmittance. A lower surface energy was achieved by depositing fluorocarbon polymers, and a micro-nano multi-scale morphology was built on the cover glass within 50 s. These two properties led to an increase in the hydrophobicity, which enhanced the self-cleaning effect of the surface. The morphology of the surface also helped to improve the transparency by reducing reflections. Both the enhanced self-cleaning effect and the improved transparency induced by the atmospheric pressure plasma treatment were confirmed by analyzing the total conversion efficiency of a solar cell by outdoor field testing.

  12. Droplet fusion by alternating current (AC) field electrocoalescence in microchannels.

    PubMed

    Chabert, Max; Dorfman, Kevin D; Viovy, Jean-Louis

    2005-10-01

    We present a system for the electrocoalescence of microfluidic droplets immersed in an immiscible solvent, where the undeformed droplet diameters are comparable to the channel diameter. The electrodes are not in direct contact with the carrier liquid or the droplets, thereby minimizing the risk of cross-contamination between different coalescence events. Results are presented for the coalescence of buffered aqueous droplets in both quiescent and flowing fluorocarbon streams, and on-flight coalescence is demonstrated. The capillary-based system presented here is readily amenable to further miniaturization to any lab-on-a-chip application where the conductivity of the droplets is much greater than the conductivity of the stream containing them, and should aid in the further application of droplet microreactors to biological analyses.

  13. 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.

  14. 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.

  15. Anomalous pH dependent stability behavior of surfactant-free nonpolar oil drops in aqueous electrolyte solutions.

    PubMed

    Clasohm, Lucy Y; Vakarelski, Ivan U; Dagastine, Raymond R; Chan, Derek Y C; Stevens, Geoffrey W; Grieser, Franz

    2007-08-28

    Recent advances in atomic force microscopy (AFM) force measurement techniques have allowed the direct measurement and theoretical interpretation of the interaction between a liquid droplet and a solid surface or between two liquid droplets. In this study, we investigated the interaction across an aqueous thin film between fluorocarbon (perfluoropentane) droplets, hydrocarbon (tetradecane) droplets, and a droplet and a flat mica surface in the absence of stabilizers. It was found that even at a relatively elevated electrolyte concentration of 0.1 M NaNO3, depending on the solution pH, interactions between two identical droplets or a droplet and a mica surface could be repulsive. A simple theoretical analysis of the magnitude and range of these interactive forces suggests that the DLVO theory cannot explain the observed behavior. The measured force behavior is discussed in the context of ion adsorption, and the arising charging effects, at the bare oil-water interface.

  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. ICP Reactor Modeling: CF4 Discharge

    NASA Technical Reports Server (NTRS)

    Bose, Deepak; Govindan, T. R.; Meyyappan, M.

    1999-01-01

    Inductively coupled plasma (ICP) reactors are widely used now for etching and deposition applications due to their simpler design compared to other high density sources. Plasma reactor modeling has been playing an important role since it can, in principle, reduce the number of trial and error iterations in the design process and provide valuable understanding of mechanisms. Fluorocarbon precursors have been the choice for oxide etching. We have data available on CF4 from our laboratory. These are current voltage characteristics, La.ngmuir probe data, UV-absorption, and mass spectrometry measurements in a GEC-ICP reactor. We have developed a comprehensive model for ICP reactors which couples plasma generation and transport and neutral species dynamics with the gas flow equations. The model has been verified by comparison with experimental results for a nitrogen discharge in an ICP reactor. In the present work, the model has been applied to CF4 discharge and compared to available experimental data.

  18. Reconfigurable and responsive droplet-based compound micro-lenses

    PubMed Central

    Nagelberg, Sara; Zarzar, Lauren D.; Nicolas, Natalie; Subramanian, Kaushikaram; Kalow, Julia A.; Sresht, Vishnu; Blankschtein, Daniel; Barbastathis, George; Kreysing, Moritz; Swager, Timothy M.; Kolle, Mathias

    2017-01-01

    Micro-scale optical components play a crucial role in imaging and display technology, biosensing, beam shaping, optical switching, wavefront-analysis, and device miniaturization. Herein, we demonstrate liquid compound micro-lenses with dynamically tunable focal lengths. We employ bi-phase emulsion droplets fabricated from immiscible hydrocarbon and fluorocarbon liquids to form responsive micro-lenses that can be reconfigured to focus or scatter light, form real or virtual images, and display variable focal lengths. Experimental demonstrations of dynamic refractive control are complemented by theoretical analysis and wave-optical modelling. Additionally, we provide evidence of the micro-lenses' functionality for two potential applications—integral micro-scale imaging devices and light field display technology—thereby demonstrating both the fundamental characteristics and the promising opportunities for fluid-based dynamic refractive micro-scale compound lenses. PMID:28266505

  19. Nano-coatings on carbon structures for interfacial modification

    NASA Astrophysics Data System (ADS)

    Pulikollu, Rajasekhar V.

    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

  20. Superhydrophobic behavior of fluorinated carbon nanofiber arrays

    NASA Astrophysics Data System (ADS)

    Hsieh, Chien-Te; Fan, Wen-Syuan

    2006-06-01

    Superhydrophobic behavior of fluorinated carbon nanofiber (CNF) arrays, prepared by a template-assisted synthesis, has been investigated. A thermal chemical vapor method, using perfluorohexane as the precursor, was used to coat fluorocarbon on the surface of the CNFs, thus lowering their surface tension. The F-coated CNFs exhibited a good water-repellent behavior, i.e., the highest value of contact angle ˜166°. The superhydrophobicity of water droplets on the arrays can be well predicted by a modified Cassie-Baxter model, incorporating the pore size distributions determined from the density functional theory method. This satisfactory result would shed one light on how the variation of opened sizes would induce the superhydrophobicity of nanostructured surfaces.

  1. Treatment of N2O in pulsed microwave torch discharge

    NASA Astrophysics Data System (ADS)

    Jasiński, M.; Czylkowski, D.; Zakrzewski, Z.; Mizeraczyk, J.

    2004-03-01

    Results of using a moderate-power (several hundred Watts) pulsed microwave torch plasma (MTP) to the conversion of atmospheric-pressure nitrous oxide (N2O) into nitrogen oxides (NO, NO2 and N2O4) are presented. The pulsed regime allowed to decrease the average power used, resulting in a higher value of energy efficiency by about 10% (reaching several hundred g[N2O]/kWh) at the same efficiency of the decomposition of N2O (70÷90%) as at the continuous operation of MTP. The removal rate increased up to 200 g[N2O]/h. The obtained results suggest the pulsed MTP promising for efficient decomposition of various gaseous pollutants, e.g. fluorocarbons.

  2. Direct determination of surface tension in the lung.

    PubMed

    Schürch, S; Goerke, J; Clements, J A

    1976-12-01

    We have used the spreading behavior of small drops of several fluorocarbon fluids and silicone oil on air-liquid interfaces to measure the surface tension of lungs in situ. The test fluids were calibrated in a surface balance at 37 degrees on monolayers of dipalmitoylphosphatidylcholine. At particular surface tensions characteristic of each fluid used, an increase in the tension of 1 mN/m or less caused the droplets to spread reversibly from a sphere to a lens shape. Using micropipettes we placed such droplets on the alveolar surfaces of excised rat lungs held at functional residual capacity and 37 degrees and found that the surface tension remained below 9 mN/m for at least 30 min. The surface tension-volume relationship was linear for tensions ranging from 9 to 20 mN/m.

  3. Actuation and Control of Droplets by Using Electrowetting-on-Dielectric

    NASA Astrophysics Data System (ADS)

    Zeng, Xue-Feng; Yue, Rui-Feng; Wu, Jian-Gang; Dong, Liang; Liu, Li-Tian

    2004-09-01

    Electrowetting-on-dielectric (EWOD) controls directly the wettability of liquids on the solid surface by applying an electric potential to the microelectrode array under the dielectric layer. A prototype of the EWOD droplet actuator is put forward, consisting of Si used as the substrate of the microelectrode array, Si3N4 film as the dielectric layer and fluorocarbon polymer (p-C:F) film deposited by plasma enhanced chemical vapour deposition (PECVD) as the hydrophobic layer. The p-C:F film was uniform and compact, and the contact angle of deionized water on the p-C:F film reached 110 degrees . The actuator successfully actuated deionized droplets surrounded in silicone oil at the voltage of 35 V.

  4. Sorting and Manipulation of Magnetic Droplets in Continuous Flow

    NASA Astrophysics Data System (ADS)

    Al-Hetlani, Entesar; Hatt, Oliver J.; Vojtíšek, Martin; Tarn, Mark D.; Iles, Alexander; Pamme, Nicole

    2010-12-01

    We report the rapid on-chip generation and subsequent manipulation of magnetic droplets in continuous flow. Magnetic droplets were formed using aqueous-based ferrofluid as the dispersed phase and fluorocarbon oil as the continuous phase. Droplet manipulation was demonstrated with simple permanent magnets using two microfluidic platforms: (i) flow focusing droplet generation followed by their splitting into daughter droplets containing different amounts of magnetic nanoparticles, and (ii) droplet generation at a T-junction and their downstream deflection across a chamber for sorting based on the applied magnetic field and magnetite loading of the droplet. Both systems show great potential for performing a wide range of high throughput continuous flow processes including sample dilution, cell sorting and screening, and microparticle fabrication.

  5. Influence of melt mixer on injection molding of thermoset elastomers

    NASA Astrophysics Data System (ADS)

    Rochman, Arif; Zahra, Keith

    2016-10-01

    One of the drawbacks in injection molding is that the plasticizing screw is short such that polymers having high concentrations of additives, such as thermoset elastomers, might not mix homogeneously within the short period of time during the plasticizing stage. In this study, various melt mixers inside the nozzle chamber, together forming a mixing nozzle, were developed. Three different materials were investigated, namely nitrile butadiene rubber (NBR), ethylene propylene-diene monomer (EPDM) and fluorocarbon (FKM). The use of these melt mixers resulted in better homogeneity and properties of the molded parts despite a curing time reduction of 10 s. This was due to the increase in mixing and shearing introduced a higher rate of crosslinking formation in the molded parts.

  6. The evolution of spatial ordering of oil drops fast spreading on a water surface

    NASA Astrophysics Data System (ADS)

    Yamamoto, Daigo; Nakajima, Chika; Shioi, Akihisa; Krafft, Marie Pierre; Yoshikawa, Kenichi

    2015-05-01

    The design of dynamically self-assembled systems is of high interest in science and technology. Here, we report a unique cascade in the self-ordering of droplets accompanied by a dewetting transition. The dynamic self-emergent droplets are observed when a thin liquid layer of an immiscible fluorocarbon oil (perfluorooctyl bromide, PFOB) is placed on a water surface. Due to the gradual evaporation of PFOB, a circular PFOB-free domain appears as a result of a local dewetting transition. A circular pearling structure is generated at the rim with the growth of the dewetting hole. As the next stage, linear arrays of droplets are generated in a radial manner from the centre of the hole. These one-dimensional arrangements then evolve into two-dimensional hexagonal arrays of microdroplets through collective rhythmical shrinking/expanding motions. The emergence of such dynamic patterns is discussed in terms of the nonlinear kinetics of the dewetting transition under thermodynamically dissipative conditions.

  7. 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.

  8. 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).

  9. 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.

  10. Polyvinylamine: a tool for engineering interfaces.

    PubMed

    Pelton, Robert

    2014-12-30

    With the highest content of primary amine functional groups of any polymer, polyvinylamine (PVAm) is a potent tool for the modification of macroscopic and nanoparticle surfaces. Based on the free radical polymerization and subsequent hydrolysis of N-vinylformamide, PVAm is prepared as linear polymers (0.8 kDa to >1 MDa), microgels, macrogels, and copolymers. The amine groups serve as reaction sites for grafting PVAm to surfaces and for the preparation of derivatives. Coupling low-molecular-weight molecules and oligomers gives PVAm-X, where X includes hydrophobes, carbohydrate oligomers, proteins, TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy), phenylboronic acids, and fluorocarbons. This contribution highlights the use of PVAm and PVAm-X to modify solid surface properties. Where possible, the PVAm properties and applications as an interfacial agent are compared to those of linear polyethylenimine, polyallylamine, and chitosan.

  11. 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).

  12. Low-surface energy surfactants with branched hydrocarbon architectures.

    PubMed

    Alexander, Shirin; Smith, Gregory N; James, Craig; Rogers, Sarah E; Guittard, Frédéric; Sagisaka, Masanobu; Eastoe, Julian

    2014-04-01

    Surface tensiometry and small-angle neutron scattering have been used to characterize a new class of low-surface energy surfactants (LSESs), "hedgehog" surfactants. These surfactants are based on highly branched hydrocarbon (HC) chains as replacements for environmentally hazardous fluorocarbon surfactants and polymers. Tensiometric analyses indicate that a subtle structural modification in the tails and headgroup results in significant effects on limiting surface tensions γcmc at the critical micelle concentration: a higher level of branching and an increased counterion size promote an effective reduction of surface tension to low values for HC surfactants (γcmc ∼ 24 mN m(-1)). These LSESs present a new class of potentially very important materials, which form lamellar aggregates in aqueous solutions independent of dilution.

  13. 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.

  14. 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.

  15. 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, Sudbury—ON, 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.

  16. 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.

  17. 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.

  18. Reactive ion etching effects on carbon-doped Ge2Sb2Te5 phase change material in CF4/Ar plasma

    NASA Astrophysics Data System (ADS)

    Shen, Lanlan; Song, Sannian; Song, Zhitang; Li, Le; Guo, Tianqi; Liu, Bo; Wu, Liangcai; Cheng, Yan; Feng, Songlin

    2016-10-01

    Recently, carbon-doped Ge2Sb2Te5 (CGST) has been proved to be a high promising material for future phase change memory technology. In this article, reactive ion etching (RIE) of phase change material CGST films is studied using CF4/Ar gas mixture. The effects on gas-mixing ratio, RF power, gas pressure on the etch rate, etch profile and roughness of the CGST film are investigated. Conventional phase change material Ge2Sb2Te5 (GST) films are simultaneously studied for comparison. Compared with GST film, 10 % more CF4 is needed for high etch rate and 10% less CF4 for good anisotropy of CGST due to more fluorocarbon polymer deposition during CF4 etching. The trends of etch rates and roughness of CGST with varying RF power and chamber pressure are similar with those of GST. Furthermore, the etch rate of CGST are more easily to be saturated when higher RF power is applied.

  19. Network flow model analysis of the impact of chlorofluorocarbon phaseout on acid-grade fluorspar. Information circular/1994

    SciTech Connect

    Slatnick, J.A.; Fulton, R.B.

    1994-12-31

    Chlorofluorocarbons (CFC`s) are being phased out and eventually banned under extensive international agreements because the chlorine in CFC`s is thought to deplete the Earth`s ozone layer. As a result, the fluorspar mining industry, which is the source of fluorine in fluorocarbons through intermediate hydrofluoric acid, is being affected. Concern for this impact has led the U.S. Bureau of Mines to employ its capabilities to analyze various scenarios in the evolution of CFC replacements and substitutes to determine their effect on fluorspar mining. This report utilizes a network flow model to examine the effects of proposed replacements for CFC`s, in terms of fluorine content, on fluorspar operations worldwide and on hydrofluoric acid plants in North America and Europe.

  20. New chemical alternative for ozone-depleting substances: HFC-245ca. Final report, August 1987-June 1996

    SciTech Connect

    Smith, N.D.; Gage, C.L.; Baskin, E.; Hendriks, R.V.

    1996-12-01

    The report gives results of a preliminary evaluation of a new hydrofluoro-carbon (HF)--HFC-245ca or 1,1,2,2,3-pentafluoropropane as a possible alternative for chlorofluorocarbon (CFC)-11 (trichlorofluoromethane) and hydrochloro-fluorocarbon (HCFC)-123 (1,1,1-trifluoro- 2,2-dichloroethane) refrigerant for low-pressure chillers and as a possible alternative for CFC-111 and HCFC-14lb (1-fluoro-1,1-dichloroethane) blowing agents for polyisocyanurate/polyurethane insulation forms. Evaluation tests included an examination of its flammability, stability, thermophysical properties, lubricant miscibility and lubricity, materials compatibility, acute inhalation toxicity, and refrigeration performance.An azeotrope composed of HFC-245ca and HFC-338mccq (1,1,1,2,3,4,4,4-octafluorobutane) was also examined from the standpointof reducing the flammability of HFC-245ca.

  1. 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.

  2. 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.

  3. 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.

  4. Channel electron multiplier compatibility with Viton and Apiezon-L vacuum grease

    NASA Technical Reports Server (NTRS)

    Mccomas, D. J.; Baldonado, J. R.; Bame, S. J.; Barraclough, B. L.

    1987-01-01

    Clean Viton and Viton coated with Apiezon-L vacuum grease were tested for their noncontaminating compatibility with channel electron multipliers (CEMs). The test setup and procedure were the same as those used previously in conjunction with CEM compatibility tests of certain epoxies, solder, and fluorocarbon polymer materials useful for construction of spaceflight sensors. While some CEM gain degradation was noted during exposure to Viton and Apiezon-L, the present tests indicate that, at least over instrument lifetimes of about 2 x 10 to the 12th counts, these materials should be suitable for (1) preflight space sensor testing systems, (2) hermetic seals for CEM-based space sensors, and (3) terrestrial CEM-based instrumentation.

  5. Development of ciprofloxacin-loaded contact lenses using fluorous chemistry.

    PubMed

    Qin, Guoting; Zhu, Zhiling; Li, Siheng; McDermott, Alison M; Cai, Chengzhi

    2017-04-01

    In this work, we developed a simple method to load drugs into commercially available contact lenses utilizing fluorous chemistry. We demonstrated this method using model compounds including fluorous-tagged fluorescein and antibiotic ciprofloxacin. We showed that fluorous interactions facilitated the loading of model molecules into fluorocarbon-containing contact lenses, and that the release profiles exhibited sustained release. Contact lenses loaded with fluorous-tagged ciprofloxacin exhibited antimicrobial activity against Pseudomonas aeruginosa in vitro, while no cytotoxicity towards human corneal epithelial cells was observed. To mimic the tear turnover, we designed a porcine eye infection model under flow conditions. Significantly, the modified lenses also exhibited antimicrobial efficacy against Pseudomonas aeruginosa in the ex vivo infection model. Overall, utilizing fluorous chemistry, we can construct a drug delivery system that exhibits high drug loading capacity, sustained drug release, and robust biological activity.

  6. 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.

  7. The Effect of Supercritical Fluids on Solid Acid Catalyst Alkylation

    SciTech Connect

    Ginosar, Daniel Michael; Thompson, David Neil; Burch, Kyle Coates; Zalewski, D. J.

    2002-05-01

    The alkylation of isobutane with trans-2-butene was explored over six solid acid catalysts in the liquid, near-critical liquid, and supercritical regions through the addition of an inert cosolvent to the reaction feed mixture. The addition of supercritical cosolvents did not result in sustained catalytic alkylation activity. A modest improvement in product yield was obtained with the addition of methane in the modified-liquid region; however, catalyst longevity and product selectivity were decreased compared to cosolvent-free liquid conditions. This paper describes the catalyst screening and selection process, an exploration of catalyst performance with varying concentrations of methane, and an examination of the effects of seven supercritical fluids on catalyst performance. The catalysts included two zeolites, two sulfated metal oxides, and two Nafion catalysts. Three hydrocarbons, two fluorocarbons, carbon dioxide, and sulfur hexafluoride were explored as inert cosolvents added to the reaction mixture.

  8. Thermophysical properties of fluorinated acrylate homopolymers: Mixing and phase separation

    NASA Astrophysics Data System (ADS)

    Roussel, F.; Saidi, S.; Guittard, F.; Geribaldi, S.

    2002-06-01

    The thermophysical properties of fluorinated acrylate homopolymers are investigated by differential scanning calorimetry (DSC) and optical microscopy and discussed in terms of relative lengths of the fluorinated chain and the hydrocarbon spacer between the acrylate moiety and the fluorinated chain. These compounds exhibit an intrinsic microphase-separation (Isotropic+Isotropic morphology) occurring between the fluorinated chains and the acrylate polymer backbone. It is shown that the enthalpy of mixing is a function of the length of the lateral fluorocarbon chains. The thermophysical behaviour of these materials may be regarded as demixed systems exhibiting an Upper Critical Solution Temperature. The photopolymerization process of one of the monomer is studied by isothermal photocalorimetry. High acrylate double-bond conversion and fast curing rates were obtained thus demonstrating the promising use of these materials for coating and film processing applications using UV-curing techniques.

  9. The reaction-field effect on the chemical potentials of polar aprotic non-aromatic liquids 1. Vapour pressure

    NASA Astrophysics Data System (ADS)

    Rosseinsky, D. R.; Stead, K.; Mowforth, C. W.

    1998-10-01

    The reaction field for the interaction of a molecule with its identical neighbours is shown to be a major determinant of the chemical potential of many dipolar liquids. The electrostatic potential w, derived for immersion of the dipolar molecule in its own kind, and notably comprising solely static and hf permittivities, is equated with the difference between the polar-liquid chemical potential and that of an isostructural non-polar hydrocarbon. For all the 26 non-aromatic Onsager liquids for which the requisite data are available, acceptable conformity is established of the vapour pressure calculated from w with that observed, fluorocarbons excepted. If w turns out to be small, vapour pressures of (these 12) dipolars approximate quite closely to those of the isostructural non-polars, as expected. For ketones and nitroalkanes varied-temperature data are available and well reproduced via w: thus calculated vaporization enthalpies equal the observed.

  10. Channel electron multiplier compatibility with Viton and Apiezon-L vacuum grease

    NASA Astrophysics Data System (ADS)

    McComas, D. J.; Baldonado, J. R.; Bame, S. J.; Barraclough, B. L.

    1987-12-01

    Clean Viton and Viton coated with Apiezon-L vacuum grease were tested for their noncontaminating compatibility with channel electron multipliers (CEMs). The test setup and procedure were the same as those used previously in conjunction with CEM compatibility tests of certain epoxies, solder, and fluorocarbon polymer materials useful for construction of spaceflight sensors. While some CEM gain degradation was noted during exposure to Viton and Apiezon-L, the present tests indicate that, at least over instrument lifetimes of about 2 x 10 to the 12th counts, these materials should be suitable for (1) preflight space sensor testing systems, (2) hermetic seals for CEM-based space sensors, and (3) terrestrial CEM-based instrumentation.

  11. Controlled synthesis of NaYF4 nanoparticles and upconversion properties of NaYF4:Yb, Er (Tm)/FC transparent nanocomposite thin films.

    PubMed

    Huang, Wenjuan; Lu, Chunhua; Jiang, Chenfei; Wang, Wei; Song, Jianbin; Ni, Yaru; Xu, Zhongzi

    2012-06-15

    Monodisperse oleic acid stabilized pure NaYF(4) nanoparticles with controlled size and shape have been successfully synthesized by changing the initial reaction temperature. Transparent nanocomposite thin films consisting of NaYF(4):Yb, Er (Tm) upconverting nanoparticles (UCNPs) and fluorocarbon resin (FC) are deposited on the slide glass by dip-coating method. The results show that these nanocomposite thin films exhibit intense green and blue upconversion photoluminescence under 980 nm laser excitation and higher transparency than blank substrate. The NaYF(4):Yb,Er (Tm) nanoparticles and NaYF(4):Yb,Er (Tm)/FC nanocomposite thin films have been characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), scanning electron microscopy (SEM), SEM/back-scattered electron (BSE), atomic force microscopy (AFM), UV-Vis spectrophotometer (UVPC), and photoluminescence (PL) spectra. These nanocomposite thin films can be potentially used in solar cells field.

  12. Effect of surface temperature on plasma-surface interactions in an inductively coupled modified gaseous electronics conference reactor

    SciTech Connect

    Zhou Baosuo; Joseph, Eric A.; Sant, Sanket P.; Liu Yonghua; Radhakrishnan, Arun; Overzet, Lawrence J.; Goeckner, Matthew J.

    2005-11-15

    The effect of wall temperature, from 50 to 200 deg. C, on gas phase chemistry and substrate etching rates has been studied in inductively coupled CF{sub 4} plasma under two distinctive initial wall conditions, namely 'clean' and 'seasoned'. During plasma etching, we found that the gas phase chemistry exhibits a weak dependence on the initial wall cleanliness when the wall is either cold (50 deg. C) or hot (200 deg. C). In the mid-temperature range, the wall cleanliness can strongly affect gas phase chemistry. The study of temperature dependence of the fluorocarbon film deposition on the substrate indicates that ion-assisted incorporation, direct ion incorporation and ion-assisted desorption are the major factors determining film growth and removal. Ion-assisted incorporation and desorption are surface-temperature-dependent, while direct ion incorporation is independent of the surface temperature.

  13. 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.

  14. Dynamically­ Reconfigurable Complex Emulsions via Tunable Interfacial Tensions

    NASA Astrophysics Data System (ADS)

    Swager, Timothy

    This lecture will focus on the design of systems wherein a reconfiguration of the materials can be triggered chemically of mechanically. The utility of these methods is to generate transduction mechanisms by which chemical and biological sensors can be developed. Three different types of systems will be discussed. (1) Particles wherein a protease enzyme releases strain in the particle by breaking crosslinks. (2) Assemblies of polymers at air water interfaces and the demonstration of a luminescence strain response upon compression. (3) Dynamic colloids produced from immiscible fluorocarbon/hydrocarbon mixtures and ability to convert the core and shell layers of the particles as well as the conversion to Janus particles. The latter system's morphology changes can be triggered chemically or optically.

  15. 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.

  16. 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.

  17. 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.

  18. Apparatus and method for atmospheric pressure reactive atom plasma processing for shaping of damage free surfaces

    DOEpatents

    Carr; Jeffrey W.

    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.

  19. Avoiding Steric’ Congestion in Dendrimer Growth through Proportionate Branching: A Twist on da Vinci’s Rule of Tree Branching

    PubMed Central

    Yue, Xuyi; Taraban, Marc B; Hyland, Laura L.

    2013-01-01

    Making defect-free macromolecules is a challenging issue in 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 9,082 Da. Monodispersity is confirmed by nuclear magnetic resonance spectroscopy, mass spectrometry and small-angle X-ray scattering. Growing different parts proportionately, as nature does, could be a general strategy to achieve defect-free synthesis of macromolecules. PMID:23039185

  20. 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.

  1. Surfactants at the Design Limit.

    PubMed

    Czajka, Adam; Hazell, Gavin; Eastoe, Julian

    2015-08-04

    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, γcmc. Particular emphasis is given to how the chemical nature and structure of the hydrophobic tails influence γcmc. 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 ϕcmc represents the volume fraction of surfactant chain fragments in a surface film at the aqueous cmc. It is shown that ϕcmc is a useful index for understanding the limiting surface tension of surfactants and can be useful for designing new superefficient surfactants.

  2. Design and prototype studies of the TOTEM Roman pot detectors

    NASA Astrophysics Data System (ADS)

    Oriunno, Marco; Battistin, Michele; David, Eric; Guglielmini, Paolo; Joram, Christian; Radermacher, Ernst; Ruggiero, Gennaro; Wu, Jihao; Vacek, Vaclav; Vins, Vaclav

    2007-10-01

    The Roman pots of the TOTEM experiment at LHC will be equipped with edgeless silicon micro-strip detectors. A detector package consists of 10 detector planes cooled at -15C in vacuum. The detector resolution is 20 μm, the overall alignment precision has to be better than 30 μm. The detector planes are composed of a kapton hybrid glued on a substrate made of low expansion alloy, CE07 with 70% Si and 30% Al. An evaporative cooling system based on the fluorocarbon C3F8 with oil-free compressors has been adopted. The throttling of the fluid is done locally through capillaries. A thermo-mechanical prototype has been assembled. The results fully match the requirements and the expectations of calculations. They show a low thermal gradient on the cards and a uniform temperature distribution over the 10 planes.

  3. 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.

  4. 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.

  5. Neutron radigoraphy of fluid flow for geothermal energy research

    SciTech Connect

    Bingham, Philip R.; Polsky, Yarom; Anovitz, L.; Carmichael, Justin R.; Bilheux, Hassina Z; Jacobson, David; Hussey, Dan

    2015-01-01

    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.

  6. 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.

  7. Investigation on surface structure of potassium permanganate/nitric acid treated poly(tetrafluoroethylene)

    NASA Astrophysics Data System (ADS)

    Fu, Congli; Liu, Shuling; Gong, Tianlong; Gu, Aiqun; Yu, Zili

    2014-10-01

    In the previous articles concerning the treatment of poly(tetrafluoroethylene) (PTFE) with potassium permanganate/nitric acid mixture, the conversion of a hydrophobic to a hydrophilic surface was partially assigned to the defluorination of PTFE and then the introduction of carbonyl and hydroxyl groups into the defluorinated sites. In the present work, PTFE sheets were treated with potassium permanganate/nitric acid, and the surfaces before and after treatment were comparatively characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The surface sediments of the treated PTFE were also determined by atomic absorption spectroscopy (AAS). The results indicate that the conversion of the hydrophobicity to the hydrophilicity on the modified PTFE surface is mainly due to the deposition of hydrophilic manganese oxides which covered the fluorocarbon surface, and no detectable chemical reactions of PTFE occur in the treating process.

  8. Study of spatial homogeneity and nitridation of an Al nanopattern template with spectroscopic photoemission and low energy electron microscopy

    NASA Astrophysics Data System (ADS)

    Qi, B.; Ólafsson, S.; Zakharov, A. A.; Göthelid, M.; Agnarsson, B.; Gislason, H. P.

    2013-01-01

    We report a study on the spatial homogeneity and nitridation of a nanopattern template using a spectroscopic photoemission and low energy electron microscopy. The template was composed of Al nanodots which were patterned into a SiO2/Si(1 1 1) surface using e-beam lithography and reactive ion etching. The template exhibited a global inhomogeneity in terms of the local topography, Al composition and structure of the individual nanopatterns. After nitridation, the individual nanopatterns were diminished, more corrugated and faceted. The nitridated nanopatterns were structurally ordered but differently orientated. The nitridation effectively removed the fluorine contaminants by decomposition of the fluorocarbon sidewalls, resulting in the AlN nanopatterns and partially nitridated Si substrate surface outside the nanopattern domains.

  9. Synthesis of a polymerizable fluorosurfactant for the construction of stable nanostructured proton-conducting membranes.

    PubMed

    Wadekar, Mohan N; Jager, Wolter F; Sudhölter, Ernst J R; Picken, Stephen J

    2010-10-15

    The synthesis of the polymerizable fluorinated surfactant sodium 1,1,2,2-tetrafluoro-2-(1,1,2,2-tetrafluoro-2-(4-vinylphenyl)ethoxy)ethanesulfonate (1) and a number of related fluorocarbon compounds is described. Compound 1 is synthesized using a copper-mediated cross-coupling reaction of 4-bromobenzaldehyde and sodium 5-iodooctafluoro-3-oxapentanesulfonate. The resulting benzaldehyde is converted to a styrene unit using a Wittig reaction with methyltriphenylphosphonium bromide in acetonitrile, using DBU as a base. This strategy for converting an iodo-functionalized fluorosurfactant to a styrene-containing fluorosurfactant is highly efficient because both reactions are performed in polar solvents and are compatible with the sulfonate moiety. In addition, the copper-mediated cross-coupling reaction is most efficient with electron-poor aryl bromides like 4-bromobenzaldehyde. We wish to employ 1 for the construction of nanostructured membranes by polymerization of 1 in a microemulsion or in lyotropic liquid crystalline phases.

  10. 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.

  11. The HERMES dual-radiator ring imaging Cherenkov detector

    NASA Astrophysics Data System (ADS)

    Akopov, N.; Aschenauer, E. C.; Bailey, K.; Bernreuther, S.; Bianchi, N.; Capitani, G. P.; Carter, P.; Cisbani, E.; De Leo, R.; De Sanctis, E.; De Schepper, D.; Djordjadze, V.; Filippone, B. W.; Frullani, S.; Garibaldi, F.; Hansen, J.-O.; Hommez, B.; Iodice, M.; Jackson, H. E.; Jung, P.; Kaiser, R.; Kanesaka, J.; Kowalczyk, R.; Lagamba, L.; Maas, A.; Muccifora, V.; Nappi, E.; Negodaeva, K.; Nowak, W.-D.; O'Connor, T.; O'Neill, T. G.; Potterveld, D. H.; Ryckbosch, D.; Sakemi, Y.; Sato, F.; Schwind, A.; Shibata, T.-A.; Suetsugu, K.; Thomas, E.; Tytgat, M.; Urciuoli, G. M.; Van de Kerckhove, K.; Van de Vyver, R.; Yoneyama, S.; Zohrabian, H.; Zhang, L. F.

    2002-03-01

    The construction and use of a dual radiator Ring Imaging Cherenkov (RICH) detector is described. This instrument was developed for the HERMES experiment at DESY which emphasises measurements of semi-inclusive deep-inelastic scattering. It provides particle identification for pions, kaons, and protons in the momentum range from 2 to 15 GeV, which is essential to these studies. The instrument uses two radiators, C 4F 10, a heavy fluorocarbon gas, and a wall of silica aerogel tiles. The use of aerogel in a RICH detector has only recently become possible with the development of clear, large, homogeneous and hydrophobic aerogel. A lightweight mirror was constructed using a newly perfected technique to make resin-coated carbon-fiber surfaces of optical quality. The photon detector consists of 1934 photomultiplier tubes (PMT) for each detector half, held in a soft steel matrix to provide shielding against the residual field of the main spectrometer magnet.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. Solvent organization around the perfluoro group of coumarin 153 governs its photophysical properties: An experimental and simulation study of coumarin dyes in ethanol as well as fluorinated ethanol solvents.

    PubMed

    Mondal, Saptarsi; Halder, Ritaban; Biswas, Biswajit; Jana, Biman; Singh, Prashant Chandra

    2016-05-14

    The self-aggregation property of the perfluoro group containing molecules makes it important in the research fields of biology and polymer and organic synthesis. In the quest of understanding the role of the perfluoro group on the photophysical properties of perfluoro-containing molecules in biologically important fluoroethanol solvents, we have applied photophysical as well as molecular dynamics simulation techniques to explore the properties of perfluoro groups containing molecule coumarin-153 (C153) in ethanol (ETH), monofluoroethanol (MFE), difluoroethanol (DFE), and trifluoroethanol (TFE) and compared them with the molecules without perfluoro moiety, namely coumarin-6H (C6H) and coumarin-480 (C480). In contrast to C6H and C480, the excited state lifetime of C153 in fluorinated ETHs is not monotonic. The excited state lifetime of C153 decreases in MFE and DFE as compared to ETH, whereas in TFE, it increases as compared to MFE and DFE. Molecular dynamics simulation reveals that the carbon terminal away from the OH group of fluorinated ETHs has a preferential orientation near the perfluoro (CF3) group of C153. In MFE and DFE, the CF3 group of C153 prefers to have a CF2-F⋯H -(CHF) type of electrostatic interaction over CF2-F⋯F -(CH2) kind of dispersion interaction which increases the rate of nonradiative decay, probably due to the electrostatic nature of the CF2-F⋯H -(CHF) hydrogen bond. On the other hand, in TFE, C-F⋯ F-C type of dispersion interaction, also known as fluorous interaction, takes place between the CF3 groups of C153 and TFE which decreases the rate of nonradiative rate as compared to MFE and DFE, leading to the increased lifetime of C153 in TFE. Photophysical and MD simulation studies clearly depict that the structural organization of solvents and their interaction with the fluorocarbon group are crucial factors for the photophysical behavior of the fluorocarbon containing molecules.

  17. Role of acentric displacements on the crystal structure and second-harmonic generating properties of RbPbCO3F and CsPbCO3F.

    PubMed

    Tran, T Thao; Halasyamani, P Shiv; Rondinelli, James M

    2014-06-16

    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 P6m2 (crystal class 6m2). 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 Pb(2+). 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.

  18. 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.

  19. High-throughput microcoil NMR of compound libraries using zero-dispersion segmented flow analysis.

    PubMed

    Kautz, Roger A; Goetzinger, Wolfgang K; Karger, Barry L

    2005-01-01

    An automated system for loading samples into a microcoil NMR probe has been developed using segmented flow analysis. This approach enhanced 2-fold the throughput of the published direct injection and flow injection methods, improved sample utilization 3-fold, and was applicable to high-field NMR facilities with long transfer lines between the sample handler and NMR magnet. Sample volumes of 2 microL (10-30 mM, approximately 10 microg) were drawn from a 96-well microtiter plate by a sample handler, then pumped to a 0.5-microL microcoil NMR probe as a queue of closely spaced "plugs" separated by an immiscible fluorocarbon fluid. Individual sample plugs were detected by their NMR signal and automatically positioned for stopped-flow data acquisition. The sample in the NMR coil could be changed within 35 s by advancing the queue. The fluorocarbon liquid wetted the wall of the Teflon transfer line, preventing the DMSO samples from contacting the capillary wall and thus reducing sample losses to below 5% after passage through the 3-m transfer line. With a wash plug of solvent between samples, sample-to-sample carryover was <1%. Significantly, the samples did not disperse into the carrier liquid during loading or during acquisitions of several days for trace analysis. For automated high-throughput analysis using a 16-second acquisition time, spectra were recorded at a rate of 1.5 min/sample and total deuterated solvent consumption was <0.5 mL (1 US dollar) per 96-well plate.

  20. Self-adapting peripherally heterofunctionalized hyperbranched polymers: formation of Janus and tripodal structures.

    PubMed

    Samuel, Ashok Zachariah; Ramakrishnan, S

    2013-01-29

    A peripherally clickable hyperbranched polyester carrying numerous propargyl terminal groups was prepared by a simple melt transesterification polycondensation of a suitably designed AB(2) monomer; this clickable hyperscaffold was then transformed into a variety of different derivatives by using the Cu-catalyzed azide-yne click reaction. Functionalization of the periphery with equimolar quantities of mutually immiscible segments, such as hydrocarbon, fluorocarbon, and PEG, yielded frustrated molecular systems that readapt and form structures wherein the immiscible segments appear to self-segregate to generate either Janus structures (when two immiscible segments are present) or tripodal structures (when three immiscible segments are present). Evidence for such self-segregation was obtained from a variety of studies, such as differential scanning calorimetry, Langmuir isotherms, AFM imaging, and small-angle X-ray scattering measurements. Crystallization of one or more of the peripheral segments reinforced this self-segregation; the weight-fraction-normalized enthalpies of melting associated with the different domains revealed a competition between the segments to optimize their crystalline organization. When one or more of the segments are amorphous, the remaining segments crystallize more effectively and consequently exhibit a higher melting enthalpy. AFM images of monolayers, transferred from the Langmuir trough, revealed that the thickness matches the expected values; furthermore, contact angle measurements clearly demonstrated that the monolayer films are fairly hydrophobic, and in the case of the tripodal hybramers, the presence of domains of hydrocarbon and fluorocarbon appears to impart nanoscale chemical heterogeneity that is reflected in the strong hysteresis in the advancing and receding contact angles.

  1. Controlling modulus and morphology of hydrogel tubes through surface modification.

    PubMed

    Enescu, Cristina; Shoichet, Molly S

    2004-01-01

    Crosslinked, porous poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) (PHEMA-MMA) tubes were prepared in cylindrical glass molds using a new centrifugal casting process developed in our group. The resulting hydrogel tubes have a bi-phasic wall structure, with a spongy inner layer and a gel-like outer layer, the latter of which provides mechanical strength to the tube. While many factors influence wall morphology and, thus, mechanical properties, we focused on the effect of the surface properties of the glass mold in which tubes are synthesized. Specifically, we investigated the impact of a diverse set of silane modifications of the glass mold on tube morphology, elastic modulus and mold release. We treated activated glass surfaces with one of three alkoxysilanes having either ethoxy, amine or fluorocarbon end-groups. Silane-modified glass surfaces were found to be more hydrophobic than the unmodified glass mold, with the most hydrophobic surface being that of the fluorocarbon-terminated silane. The presence of the silane layer on the mold was confirmed by X-ray photoelectron spectroscopy and the stability of this modification was confirmed by examining the surface chemistry of the hydrogel tubes. The biphasic hydrogel tube wall structure was observed for all tubes, yet those tubes synthesized in unmodified molds had a cracked outer morphology, whereas those synthesized in silane-modified molds had a smooth outer morphology. This influenced the mechanical properties of the tubes where tubes synthesized in silane-modified molds had a significantly greater elastic modulus than those tubes synthesized in unmodified molds. Release from the molds was easiest with ethoxy- and amine-functionalized silane mold modifications.

  2. 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.

  3. The parameter stability of a high dk rigid lens material.

    PubMed

    Woods, C; Efron, N

    1999-01-01

    The use of rigid materials with high oxygen permeability (Dk) is on the increase, their major benefit being the reduction of hypoxia. However, there is a reluctance to use these materials possibly due to increased surface scratching, reduced wettability, increased deposition, reduced life expectancy and parameter instability. Considering parameter stability, various studies have demonstrated contradictory results or used high Dk materials based on the silicone acrylate polymer. This study was designed to investigate whether the parameters of a high Dk rigid fluorocarbon contact lens material changed during daily wear and extended wear schedules. Thirty five subjects, divided into group groups, Group I wore the lens on a daily wear basis, whereas those in Group II wore the lens on a monthly extended wear basis. The parameters and integrity of the lenses were monitored in both groups every 3 months. For lens integrity a statistically significant increase in surface scratching was demonstrated for the lenses worn by the subjects of both groups over the time of the study (Group I, F=7.990, P <0.0001 [ANCOVA]; Group II, F=6.241, P=0.003 [ANCOVA]). The only parameter to show a statistically significant variation over the study period was that of centre thickness for the lenses worn by the subjects in Group I (F=3.976, P=0.0063 [ANCOVA]), with a mean reduction in centre thickness of 0.022 mm at the 12 month visit. No change was noted for either group or between groups for the other parameters measured. This study demonstrates that the parameters of rigid contact lenses manufactured from high Dk fluorocarbons are stable with only a non-clinically significant reduction in centre thickness for the contact lenses worn by the subjects in Group I.

  4. Electron attachment mass spectrometry as a diagnostics for electronegative gases and plasmas

    NASA Astrophysics Data System (ADS)

    Stoffels, E.; Stoffels, W. W.; Tachibana, K.

    1998-01-01

    Electron attachment mass spectrometry (EAMS) has been developed to study mixtures of electronegative gases and plasmas. A quadrupole mass spectrometer (QMS) has been used to detect negative ions, formed from sampled species by attachment of low energy electrons. Varying the electron energy allows to collect the attachment cross section of the considered species. EAMS appears to be a very powerful technique to study the chemistry of electronegative gases. Unlike ionization mass spectrometry, where cross sections are low at the threshold and rather flat over a broad range of electron energies, attachment resonances are sharp and distinct. Also very limited fragmentation of the parent negative ion occurs, so a given molecule yields only a few different negative ions. This facilitates identification of components in a gas mixture. It is particularly advantageous for detection of large, fragile molecules, which break up after ionization, but can be easily transformed into large negative ions. Moreover, sensitive detection of active species is possible due to their relatively high attachment cross sections. A particularly important application of EAMS is the determination of an effective attachment cross section in a plasma. Recording this cross section allows to decide on the actual negative ion formation mechanism in the plasma environment, where active products of plasma conversion can significantly alter the negative ion production channels and consequently the whole balance of charged particles. Examples of EAMS applications to fluorocarbon gases and low-pressure radio-frequency plasmas are discussed. In a CF4 discharge conversion of the parent gas into species like C2F6 and C3F8 is easily visualized. The dominant mechanism of negative ion formation in the plasma is electron attachment to these minority species and not to the parent gas. Also larger polymers are readily formed in fluorocarbon plasmas. In a C2F6 discharge molecules with up to ten carbon atoms (the

  5. Highly methyl-branched hydrocarbon surfactant as a CO₂-philic solubilizer for water/supercritical CO₂ microemulsion.

    PubMed

    Sagisaka, Masanobu; Kudo, Kotaro; Nagoya, Shota; Yoshizawa, Atsushi

    2013-01-01

    To develop an efficient and fluorine-free solubilizer for a water/supercritical CO₂ microemulsion (W/CO₂ μE), in this study, a highly methyl-branched alkyl, isostearyl group was focused on as a CO₂-philic tail, and the custom-made isostearyl surfactant, sodium 2-(4,4-dimethylpentan-2-yl)-5,7,7-trimethyloctyl sulfate (SIS1) was synthesized. The surface tension (γ) of an aqueous SIS1 solution was measured at ambient pressure as a function of surfactant concentration, and it was found to be 25 mN/m at concentrations of > 1.5 mM. A low γ value can generally be reached only by a fluorocarbon surfactant, which implies that SIS1 has an excellent solubilizing power for the W/CO₂ μE, similar to some fluorocarbon surfactants reported previously. Visual observations of the SIS1/W/CO₂ mixtures revealed the formation of transparent single phases without separated water, identified as W/CO₂ μE. The μE was well-stabilized at pressures > 210 bar and temperatures > 55 °C. At 75 °C and 370 bar, SIS1 was found by spectral measurements using a water-soluble UV-light absorber to solubilize water contents up to a maximum water-to-surfactant molar ratio (W0) = 50. The achievement of W0 = 50 in a W/CO₂ μE system has not been reported previously in similar hydrocarbon surfactant/W/CO₂ systems, and this demonstrates that a highly methyl-branched alkyl group can act as a good CO₂-philic group for a W/CO₂ -type surfactant.

  6. 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

  7. 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

  8. Solvent organization around the perfluoro group of coumarin 153 governs its photophysical properties: An experimental and simulation study of coumarin dyes in ethanol as well as fluorinated ethanol solvents

    NASA Astrophysics Data System (ADS)

    Mondal, Saptarsi; Halder, Ritaban; Biswas, Biswajit; Jana, Biman; Singh, Prashant Chandra

    2016-05-01

    The self-aggregation property of the perfluoro group containing molecules makes it important in the research fields of biology and polymer and organic synthesis. In the quest of understanding the role of the perfluoro group on the photophysical properties of perfluoro-containing molecules in biologically important fluoroethanol solvents, we have applied photophysical as well as molecular dynamics simulation techniques to explore the properties of perfluoro groups containing molecule coumarin-153 (C153) in ethanol (ETH), monofluoroethanol (MFE), difluoroethanol (DFE), and trifluoroethanol (TFE) and compared them with the molecules without perfluoro moiety, namely coumarin-6H (C6H) and coumarin-480 (C480). In contrast to C6H and C480, the excited state lifetime of C153 in fluorinated ETHs is not monotonic. The excited state lifetime of C153 decreases in MFE and DFE as compared to ETH, whereas in TFE, it increases as compared to MFE and DFE. Molecular dynamics simulation reveals that the carbon terminal away from the OH group of fluorinated ETHs has a preferential orientation near the perfluoro (CF3) group of C153. In MFE and DFE, the CF3 group of C153 prefers to have a CF2—F⋯H —(CHF) type of electrostatic interaction over CF2—F⋯F —(CH2) kind of dispersion interaction which increases the rate of nonradiative decay, probably due to the electrostatic nature of the CF2—F⋯H —(CHF) hydrogen bond. On the other hand, in TFE, C—F⋯ F—C type of dispersion interaction, also known as fluorous interaction, takes place between the CF3 groups of C153 and TFE which decreases the rate of nonradiative rate as compared to MFE and DFE, leading to the increased lifetime of C153 in TFE. Photophysical and MD simulation studies clearly depict that the structural organization of solvents and their interaction with the fluorocarbon group are crucial factors for the photophysical behavior of the fluorocarbon containing molecules.

  9. 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.

    2016-08-01

    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

  10. Remote plasma processing of thin film materials

    NASA Astrophysics Data System (ADS)

    Kastenmeier, Bernd E. E.

    1999-09-01

    In this thesis, phenomena and mechanisms of remote plasma processes are investigated. The plasmas are spatially separated from the sample surface. Chemically reactive species are produced in the discharge region from rather inert feed gases. They exit the discharge region and travel in the afterglow towards the reaction chamber, where primarily neutral species arrive. The interaction with the sample surface is purely chemical. The absence of direct plasma surface interactions distinguishes remote plasma Chemical Dry Etching (CDE) from other etch processes like Reactive Ion Etching (RIE) or Inductively Coupled Plasma (ICP) etching. The etch reactions in CDE are isotropic, potentially offer great etch rate ratios and minimize substrate damage due to the absence of direct plasma-surface interactions. However, some materials like silicon dioxide (SiO2) or fluorocarbon deposits are difficult to remove because of the lack of activation energy otherwise provided by ion bombardment. In CDE, rates can be enhanced by the introduction of a new reaction pathway. Remote plasma CDE of silicon nitride (Si3N4) is an example for increasing the overall reaction rate by introducing a new reaction channel. Typically, the Si3N4 surface is exposed to the fluorine rich afterglow of a fluorocarbon, nitrogen trifluoride (NF 3) or sulfur hexafluoride (SF6) based discharge. We find that the Si3N4 etch rate is dramatically enhanced when Nitric Oxide (NO) is present in the afterglow as compared to the case in which only fluorine is present. Presented here are detailed analyses of the etching of Si3N 4 and SiO2 in different chemistries. Several experimental techniques are employed to investigate the composition of the plasma and the afterglow, the surface modifications and the etch rates for tetrafluoromethane (CF4) and NF3 based processes. These measurements establish the effect of NO on the Si3N4 etch rate. The dominant mechanism for the etch rate enhancement is shown by mass spectrometry

  11. REE mobility during the alteration of Carbonatite and their economic potential.

    NASA Astrophysics Data System (ADS)

    Marien, Christian; Dijkstra, Arjan; Wilkins, Colin

    2016-04-01

    The supply risk of Rare Earth Elements is an unpredictable economic factor for the future application and development of modern technology for the EU. Therefore a better understanding of REE mobilisation during hydrothermal alteration of Carbonatites is essential for a safer supply of REE in general. The hydrothermal alteration of Carbonatite within the Fen Complex (Norway) forms a fine grained red hematized rock type, called Rødbergite, which is partially enriched in REE. The variation of REE within the Rødbergite is poorly understood and problematic for any future REE exploitation from Rødbergite. A genetic model of the formation of Rødbergite will provide more information about the economic potential of Rødbergite. The gradual transformation of carbonatite to Rødbergite is not easily observable due to sparse outcrop in the Fen Complex. A fresh road cut near the Bjørndallen farm (Fen Complex) provides a unique insight to the progressive hydrothermal alteration from carbonatite to Rødbergite and is therefore crucial for a genetic model of the formation of Rødbergite. 14 Samples were taken along the profile. The mineralogical, geochemical and textural characterization of the samples using the SEM as well as major-, trace- and isotopic elemental data revealed the breakdown of the primary minerals due to the infiltration of an oxidizing fluid along grain boundaries. The primary REE-minerals in unaltered Carbonatite are REE fluorocarbonates. With the increasing alteration to Rødbergite REE fluorocarbonates are progressively replaced by hematite. In contrast, monazite - a REE-phosphate - is the dominant REE mineral species in the Rødbergite. A transitional Rødbergite sample shows apatite aggregates with a strong preferential concentration of monazite along the rim of the apatite aggregates. This observation provides strong evidence for the solution of REE in the primary rock (carbonatite) by fluids and later precipitation of REE along phosphate bearing

  12. Key challenges and recent progress in batteries, fuel cells, and hydrogen storage for clean energy systems

    NASA Astrophysics Data System (ADS)

    Chalk, Steven G.; Miller, James F.

    Reducing or eliminating the dependency on petroleum of transportation systems is a major element of US energy research activities. Batteries are a key enabling technology for the development of clean, fuel-efficient vehicles and are key to making today's hybrid electric vehicles a success. Fuel cells are the key enabling technology for a future hydrogen economy and have the potential to revolutionize the way we power our nations, offering cleaner, more efficient alternatives to today's technology. Additionally fuel cells are significantly more energy efficient than combustion-based power generation technologies. Fuel cells are projected to have energy efficiency twice that of internal combustion engines. However before fuel cells can realize their potential, significant challenges remain. The two most important are cost and durability for both automotive and stationary applications. Recent electrocatalyst developments have shown that Pt alloy catalysts have increased activity and greater durability than Pt catalysts. The durability of conventional fluorocarbon membranes is improving, and hydrocarbon-based membranes have also shown promise of equaling the performance of fluorocarbon membranes at lower cost. Recent announcements have also provided indications that fuel cells can start from freezing conditions without significant deterioration. Hydrogen storage systems for vehicles are inadequate to meet customer driving range expectations (>300 miles or 500 km) without intrusion into vehicle cargo or passenger space. The United States Department of Energy has established three centers of Excellence for hydrogen storage materials development. The centers are focused on complex metal hydrides that can be regenerated onboard a vehicle, chemical hydrides that require off-board reprocessing, and carbon-based storage materials. Recent developments have shown progress toward the 2010 DOE targets. In addition DOE has established an independent storage material testing center

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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

  18. 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.

  19. 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

    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.

  20. Quantum cascade laser based monitoring of CF2 radical concentration as a diagnostic tool of dielectric etching plasma processes

    NASA Astrophysics Data System (ADS)

    Hübner, M.; Lang, N.; Zimmermann, S.; Schulz, S. E.; Buchholtz, W.; Röpcke, J.; van Helden, J. H.

    2015-01-01

    Dielectric etching plasma processes for modern interlevel dielectrics become more and more complex by the introduction of new ultra low-k dielectrics. One challenge is the minimization of sidewall damage, while etching ultra low-k porous SiCOH by fluorocarbon plasmas. The optimization of this process requires a deeper understanding of the concentration of the CF2 radical, which acts as precursor in the polymerization of the etch sample surfaces. In an industrial dielectric etching plasma reactor, the CF2 radical was measured in situ using a continuous wave quantum cascade laser (cw-QCL) around 1106.2 cm-1. We measured Doppler-resolved ro-vibrational absorption lines and determined absolute densities using transitions in the ν3 fundamental band of CF2 with the aid of an improved simulation of the line strengths. We found that the CF2 radical concentration during the etching plasma process directly correlates to the layer structure of the etched wafer. Hence, this correlation can serve as a diagnostic tool of dielectric etching plasma processes. Applying QCL based absorption spectroscopy opens up the way for advanced process monitoring and etching controlling in semiconductor manufacturing.

  1. Nonflammable, Nonaqueous, Low Atmospheric Impact, High Performance Cleaning Solvents

    NASA Technical Reports Server (NTRS)

    Dhooge, P. M.; Glass, S. M.; Nimitz, J. S.

    2001-01-01

    For many years, chlorofluorocarbon (CFC) and chlorocarbon solvents have played an important part in aerospace operations. These solvents found extensive use as cleaning and analysis (EPA) solvents in precision and critical cleaning. However, CFCs and chlorocarbon solvents have deleterious effects on the ozone layer, are relatively strong greenhouse gases, and some are suspect or known carcinogens. Because of their ozone-depletion potential (ODP), the Montreal Protocol and its amendments, as well as other environmental regulations, have resulted in the phaseout of CFC-113 and 1,1,1-trichloroethane (TCA). Although alternatives have been recommended, they do not perform as well as the original solvents. In addition, some analyses, such as the infrared analysis of extracted hydrocarbons, cannot be performed with the substitute solvents that contain C-H bonds. CFC-113 solvent has been used for many critical aerospace applications. CFC-113, also known as Freon (registered) TF, has been used extensively in NASA's cleaning facilities for precision and critical cleaning, in particular the final rinsing in Class 100 areas, with gas chromatography analysis of rinse residue. While some cleaning can be accomplished by other processes, there are certain critical applications where CFC-113 or a similar solvent is highly cost-effective and ensures safety. Oxygen system components are one example where a solvent compatible with oxygen and capable of removing fluorocarbon grease is needed. Electronic components and precision mechanical components can also be damaged by aggressive cleaning solvents.

  2. Evaluation of HFC 245ca and HFC 236ea as foam blowing agents

    NASA Technical Reports Server (NTRS)

    Sharpe, Jon; Macarthur, Doug; Kollie, Tom; Graves, Ron; Liu, Matthew; Hendriks, Robert V.

    1995-01-01

    Hydrochlorofluorocarbon (HCFC) 141b has been selected as the interim blowing agent for use in urethane insulations on NASA's Space Shuttle External Tank. Due to the expected limited commercial lifetime of this material, research efforts at the NASA Thermal Protection Systems Materials Research Laboratory at the Marshall Space Flight Center are now being devoted to the identification and development of alternatives with zero ozone depletion potential. Physical blowing agents identified to date have included hydrocarbons, fluorocarbons, hydrofluoroethers, and more predominantly, hydrofluorocarbons (HFCs). The majority of the HFC evaluations in industry have focused on the more readily available, low boiling candidates such as HFC 134a. Higher boiling HFC candidates that could be handled at ambient conditions and use current processing equipment would be more desirable. This paper will describe results from a research program of two such candidate HFC's performed as a cooperative effort between Martin Marietta Manned Space Systems, the U.S. Environmental Protection Agency, and Oak Ridge National Laboratories. The purpose of this effort was to perform a cursory evaluation of the developmental HFC's 245ca and 236ea as blowing agents in urethane based insulations. These two materials were selected from screening tests of 37 C2, C3, and C4 isomers based on physical properties, atmospheric lifetime, flammability, estimated toxicity, difficulty of synthesis, suitability for dual use as a refrigerant, and other factors. Solubility of the two materials in typical foam components was tested, pour foaming trials were performed, and preliminary data were gathered regarding foam insulation performance.

  3. The Zero Boil-Off Tank Experiment Contributions to the Development of Cryogenic Fluid Management

    NASA Technical Reports Server (NTRS)

    Chato, David J.; Kassemi, Mohammad

    2015-01-01

    The Zero Boil-Off Technology (ZBOT) Experiment involves performing a small scale ISS experiment to study tank pressurization and pressure control in microgravity. The ZBOT experiment consists of a vacuum jacketed test tank filled with an inert fluorocarbon simulant liquid. Heaters and thermo-electric coolers are used in conjunction with an axial jet mixer flow loop to study a range of thermal conditions within the tank. The objective is to provide a high quality database of low gravity fluid motions and thermal transients which will be used to validate Computational Fluid Dynamic (CFD) modeling. This CFD can then be used in turn to predict behavior in larger systems with cryogens. This paper will discuss the current status of the ZBOT experiment as it approaches its flight to installation on the International Space Station, how its findings can be scaled to larger and more ambitious cryogenic fluid management experiments, as well as ideas for follow-on investigations using ZBOT like hardware to study other aspects of cryogenic fluid management.

  4. Interaction of phosphorylcholine with fibronectin coatings: Surface characterization and biological performances

    NASA Astrophysics Data System (ADS)

    Montaño-Machado, Vanessa; Noël, Céline; Chevallier, Pascale; Turgeon, Stéphane; Houssiau, Laurent; Pauthe, Emmanuel; Pireaux, Jean-Jacques; Mantovani, Diego

    2017-02-01

    Coating medical devices with several bioactive molecules is an interesting approach to achieve specific biological targets upon the interaction of the biomaterial with the living environment. In this work, a fluorocarbon polymer (CFx) was first deposited by plasma treatment on stainless steel (SS) substrate and thereafter, coatings containing fibronectin (FN) and phosphorylcholine (PRC) were created for cardiovascular applications. These two biomolecules were chosen to promote endothelialization and to avoid thrombus formation, respectively. Adsorption and grafting techniques were applied - and combined - to accomplish 4 different coatings containing both molecules. However, big challenge was found to characterize a small molecule (PRC: 184 g/mol) interacting with a protein (FN: 450 kD). For the first time XPS, dynamic water contact angle, immunostaining and ToF-SIMS (imaging and depth profiling) analyses were combined to accomplish the characterization of such a coating. The most encouraging biological performances were obtained for samples where FN was grafted to the CFx film followed by the adsorption of PRC: proliferation of endothelial cells and hemocompatibility properties were observed. Promising coatings for cardiovascular applications were developed. The relevance of characterizing the coatings with high sensitive techniques and the further correlation with their biological performances were evidenced.

  5. Discrete elements for 3D microfluidics

    PubMed Central

    Bhargava, Krisna C.; Thompson, Bryant; Malmstadt, Noah

    2014-01-01

    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

  6. The effect of RGD fluorosurfactant polymer modification of ePTFE on endothelial cell adhesion, growth, and function

    PubMed Central

    Larsen, Coby C.; Kligman, Faina; Kottke-Marchant, Kandice; Marchant, Roger E.

    2007-01-01

    We have synthesized and characterized a novel peptide fluorosurfactant polymer (PFSP) modification that facilitates the adhesion and growth of endothelial cells on ePTFE vascular graft material. This PFSP consists of a poly(vinyl amine) (PVAm) backbone with integrin binding Arg-Gly-Asp (RGD) peptides and perfluorocarbon pendant branches for adsorption and stable adhesion to underlying ePTFE. Aqueous PFSP solution was used to modify the surface of fluorocarbon substrates. Following subconfluent seeding, endothelial cell (EC) adhesion and growth on PFSP was assessed by determining cell population at different time points. Spectroscopic results indicated successful synthesis of PFSP. PFSP modification of ePTFE reduced the receding water contact angle measurement from 120° to 6°, indicating successful surface modification. Quantification of cell population demonstrated reduced EC attachment efficiency but increased growth rate on RGD PFSP compared with fibronectin (FN). Actin staining revealed a well-developed cytoskeleton for ECs on RGD PFSP indicative of stable adhesion. Uptake of acetylated low-density lipoprotein and positive staining for VE-Cadherin confirm EC phenotype for adherent cells. Production of prostacyclin, a potent antiplatelet agent, was equivalent between ECs on FN and RGD PFSP surfaces. Our results indicate successful synthesis and surface modification with PFSP; this is a simple, quantitative, and effective approach to modifying ePTFE to encourage endothelial cell attachment, growth, and function. PMID:16762410

  7. Study on Colloid Vibration Current in Aqueous Solution of Binary Surfactant Mixtures: Effects of Counterions and Hydrophobic Chains.

    PubMed

    Takata, Youichi; Hyono, Atsushi; Ohshima, Hiroyuki

    2016-11-01

    In order to elucidate an electroacoustic phenomenon of mixed micelles in an aqueous solution, we measured the colloid vibration current (CVI) in aqueous solutions of binary surfactant mixtures. Based on the thermodynamic treatment of critical micelle concentration (cmc) values determined by conductivity measurements, it was expected that dodecyltrimethylammonium bromide (DTAB) and dodecyltrimethylammonium chloride (DTAC) molecules would mix ideally in the micelle. However, the micelle composition as evaluated from the CVI measurement, based on the linear dependence of the CVI value on the micelle composition, differed from the aforementioned ideality. Considering these observations, we concluded that the CVI measurement was more sensitive to the counterion distribution near the micelle surface, whereas the thermodynamically determined micelle composition included the counterions more loosely bound in the diffuse double layer due to the electroneutrality condition included in its assumption. On the other hand, the phase diagram illustrating micelle formation in the lithium dodecyl sulfate (LiDS) - lithium perfluorooctane sulfonate (LiFOS) mixture system showed a heteroazeotropic point arising from the stronger interactions between homologous surfactants than between heterologous ones. Although the concentration dependence of CVI values was expected to drastically change at a heteroazeotropic point due to the enormous variation in the density of the micelle core, the results showed a monotonous change, which suggests that the density of the micelle core varies continuously. By taking the partial molar volume of fluorocarbon compounds in the hydrocarbon compounds into account, the density of the micelle core was affected by the size of the micelle as well as its constituents.

  8. Modeling Surface Water Transport in the Central Pacific Ocean With 129I Records From Coral Skeletons

    NASA Astrophysics Data System (ADS)

    Beck, W.; Biddulph, D. L.; Russell, J. L.; Burr, G. S.; Jull, T. J.; Correge, T.; Roeder, B.

    2008-12-01

    129I occurs naturally in extremely low abundance via cosmic ray interactions in the atmosphere as well as by spontaneous fission of uranium. Oceanic concentrations of 129I have risen by several orders of magnitude during the last half century largely from environmental pollution coming from several point-source nuclear fuel reprocessing plants. In the Pacific basin, much of the increase has apparently come from the Hanford Nuclear reprocessing plant in the United States, with iodine primarily arriving via the Columbia River. Coral skeletons preserve records of 129I concentration of the surface waters from which they were deposited, yielding records with annual resolution or better. We will present three such records from different locations in the Pacific Ocean: the Solomon Islands, Easter Island and Clipperton Atoll. For this study, drill cores from living massive coral skeletons of the species Porites Lobata were collected from these sites. 129I/127I values were measured using accelerator mass spectrometry (AMS) at the University of Arizona with an NEC 3 MV Pelletron accelerator. Results from the analysis of the corals will be compared to the distribution of other mixed-layer tracers (chloro-fluorocarbons and tritium) collected during the World Ocean Circulation Experiment cruises conducted between 1990 and 2002. The 129I/127I records observed in these corals will also be compared to tracer transit time calculations determined from a 20th century simulation of the GFDL coupled-climate passive-tracer model.

  9. Bulk plasma fragmentation in a C{sub 4}F{sub 8} inductively coupled plasma: A hybrid modeling study

    SciTech Connect

    Zhao, Shu-Xia; Zhang, Yu-Ru; Gao, Fei; Wang, You-Nian; Bogaerts, Annemie

    2015-06-28

    A hybrid model is used to investigate the fragmentation of C{sub 4}F{sub 8} 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. C{sub x}F{sub y} (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 C{sub 4}F{sub 8} 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 C{sub 4}F{sub 8} reaction set used in the model. The C{sub 4}F{sub 8} 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.

  10. Regulation of adhesion behavior of murine macrophage using supported lipid membranes displaying tunable mannose domains

    NASA Astrophysics Data System (ADS)

    Kaindl, T.; Oelke, J.; Pasc, A.; Kaufmann, S.; Konovalov, O. V.; Funari, S. S.; Engel, U.; Wixforth, A.; Tanaka, M.

    2010-07-01

    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 α-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.

  11. Direct measurement of surface carbon concentrations. [in lunar soil

    NASA Technical Reports Server (NTRS)

    Filleux, C.; Tombrello, T. A.; Burnett, D. S.

    1977-01-01

    Measurements of surface concentrations of carbon in lunar soils and soil breccias provide information on the origin of carbon in the regolith. The reaction C-12 (d, p sub zero) is used to measure 'surface' and 'volume' concentrations in lunar samples. This method has a depth resolution of 1 micron, which permits only a 'surface' and a 'volume' component to be measured. Three of four Apollo 16 double drive tube samples show a surface carbon concentration of about 8 by 10 to the 14th power/sq cm, whereas the fourth sample gave 4 by 10 to the 14th power/sq cm. It can be convincingly shown that the measured concentration does not originate from fluorocarbon or hydrocarbon contaminants. Surface adsorbed layers of CO or CO2 are removed by a sputter cleaning procedure using a 2-MeV F beam. It is shown that the residual C concentration of 8 by 10 to the 14th power/sq cm cannot be further reduced by increased F fluence, and it is therefore concluded that it is truly lunar. If one assumes that the measured surface C concentration is a steady-state concentration determined only by a balance between solar-wind implantation and sputtering, a sputter erosion rate of 0.1 A/yr is obtained. However, it would be more profitable to use an independently derived sputter erosion rate to test the hypothesis of a solar-wind origin of the surface carbon.

  12. A robust superhydrophobic PVDF composite coating with wear/corrosion-resistance properties

    NASA Astrophysics Data System (ADS)

    Wang, Huaiyuan; Liu, Zhanjian; Wang, Enqun; Yuan, Ruixia; Gao, Dong; Zhang, Xiguang; Zhu, Yanji

    2015-03-01

    A robust wear/corrosion-resistant superhydrophobic polyvinylidene fluoride (PVDF)/fluorinated ethylene propylene (FEP)/carbon nanofibers (CNFs) composite coating with a water contact angle (WCA) of 164 ± 1.5° and a slide angle of 5 ± 0.2° has been fabricated through the combination of chemical etching and spraying technique. The WCA of the coating still maintains 141 ± 1.2° after 10,000 times rubbing due to the designed internal nano/micro-structure and the slide angle increases from 5 ± 0.2° to 20 ± 0.5°. The prepared coating also demonstrates excellent corrosion-resistance property under strongly acidic or alkaline conditions for 15 days. The wear-resistance of the superhydrophobic coating is approximately 5 times higher than the pure PVDF coating and commercial fluorocarbon coating. These excellent mechanical properties are attributed to the new groups of Cdbnd C and Csbnd C by dehydrofluorination of PVDF and the new β-phase of PVDF by recrystallization of the α-phase. Furthermore, the enhanced adhesive ability of the coating corresponds with Grade 1 according to GB/T9286, mainly because that the interaction force among PVDF macromolecules can be intensified by chemical cross-linking and the hydroxyl groups formed on the surface of the aluminum plate by etching. It is believed that this robust multifunctional superhydrophobic coating may have the potential values in large-scale application.

  13. 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.

  14. Facile Fabrication of Lubricant-Infused Wrinkling Surface for Preventing Thrombus Formation and Infection.

    PubMed

    Yuan, Shuaishuai; Luan, Shifang; Yan, Shunjie; Shi, Hengchong; Yin, Jinghua

    2015-09-02

    Despite the advanced modern biotechniques, thrombosis and bacterial infection of biomedical devices remain common complications that are associated with morbidity and mortality. Most antifouling surfaces are in solid form and cannot simultaneously fulfill the requirements for antithrombosis and antibacterial efficacy. In this work, we present a facile strategy to fabricate a slippery surface. This surface is created by combining photografting polymerization with osmotically driven wrinkling that can generate a coarse morphology, and followed by infusing with fluorocarbon liquid. The lubricant-infused wrinkling slippery surface can greatly prevent protein attachment, reduce platelet adhesion, and suppress thrombus formation in vitro. Furthermore, E. coli and S. aureus attachment on the slippery surfaces is reduced by ∼98.8% and ∼96.9% after 24 h incubation, relative to poly(styrene-b-isobutylene-b-styrene) (SIBS) references. This slippery surface is biocompatible and has no toxicity to L929 cells. This surface-coating strategy that effectively reduces thrombosis and the incidence of infection will greatly decrease healthcare costs.

  15. Roughness formation on photoresist during etching examined by HBr plasma-beam

    NASA Astrophysics Data System (ADS)

    Sekine, Makoto; Zhang, Yan; Ishikawa, Kenji; Takeda, Keigo; Kondo, Hiroki; Hori, Masaru; Plasma Nanotechnology Team

    2014-10-01

    For highly precise patterning in device fabrication, it is required to suppress roughness formations on photoresist (PR) polymers during plasma etching. HBr plasma treatment called ``plasma cure'' was proposed to reduce the roughness. By using a beam irradiation, we reported the PR roughness formation in fluorocarbon plasma, and the effect of HBr cure. We report the roughness formation mechanism by surface analyses and power spectral density (PSD) of the roughness. Average slope and roll-off frequency of PSD are characterized by frequency components, the high-frequency roughness. We treated the data for six samples: a) pristine, b) after Ar plasma irradiation, c) after Ar plasma followed by HBr cure, d) after HBr cure, e) after HBr followed by Ar plasma beam, and f) after HBr followed by H2 and Ar plasma beam irradiations. The PSD slopes were changed by each process. Based on the results, we speculated that the Ar-plasma beam formed a crust layer on the PR surface with unrelieved stress and HBr cure may soften the bulk PR to relieve the stress and cause agglomeration of polymers at the size over 10 nm.

  16. Computational modeling study of the radial line slot antenna microwave plasma source with comparisons to experiments

    SciTech Connect

    Raja, Laxminarayan L.; Mahadevan, Shankar; Ventzek, Peter L. G.; Yoshikawa, Jun

    2013-05-15

    The radial line slot antenna plasma source is a high-density microwave plasma source comprising a high electron temperature source region within the plasma skin depth from a coupling window and low electron temperature diffusion region far from the window. The plasma is typically comprised of inert gases like argon and mixtures of halogen or fluorocarbon gases for etching. Following the experimental study of Tian et al.[J. Vac. Sci. Technol. A 24, 1421 (2006)], a two-dimensional computational model is used to describe the essential features of the source. A high density argon plasma is described using the quasi-neutral approximation and coupled to a frequency-domain electromagnetic wave solver to describe the plasma-microwave interactions in the source. The plasma is described using a multispecies plasma chemistry mechanism developed specifically for microwave excitation conditions. The plasma is nonlocal by nature with locations of peak power deposition and peak plasma density being very different. The spatial distribution of microwave power coupling depends on whether the plasma is under- or over-dense and is described well by the model. The model predicts the experimentally observed low-order diffusion mode radial plasma profiles. The trends of spatial profiles of electron density and electron temperature over a wide range of power and pressure conditions compare well with experimental results.

  17. Self-cleaning and antibiofouling enamel surface by slippery liquid-infused technique

    PubMed Central

    Yin, JiaLi; Mei, May Lei; Li, QuanLi; Xia, Rong; Zhang, ZhiHong; Chu, Chun Hung

    2016-01-01

    We aimed to create a slippery liquid-infused enamel surface with antibiofouling property to prevent dental biofilm/plaque formation. First, a micro/nanoporous enamel surface was obtained by 37% phosphoric acid etching. The surface was then functionalized by hydrophobic low-surface energy heptadecafluoro-1,1,2,2-tetra- hydrodecyltrichlorosilane. Subsequent infusion of fluorocarbon lubricants (Fluorinert FC-70) into the polyfluoroalkyl-silanized rough surface resulted in an enamel surface with slippery liquid-infused porous surface (SLIPS). The results of water contact angle measurement, diffuse-reflectance Fourier transform infrared spectroscopy, and atomic force microscope confirmed that the SLIPS was successfully constructed on the enamel surface. The antibiofouling property of the SLIPS was evaluated by the adsorption of salivary protein of mucin and Streptococcus mutans in vitro, as well as dental biofilm formation using a rabbit model in vivo. The results showed that the SLIPS on the enamel surface significantly inhibited mucin adhesion and S. mutans biofilm formation in vitro, and inhibited dental plaque formation in vivo. PMID:27181424

  18. Low Temperature Plasma Surface Interactions: Atomic Layer Etching And Atmospheric Pressure Plasma Jet Modification Of Biomaterials

    NASA Astrophysics Data System (ADS)

    Oehrlein, Gottlieb

    2013-09-01

    Control of plasma-surface interactions is essential for successful application of low temperature plasma to materials processing. We review work performed in our laboratory in two areas: First, low pressure plasma surface interaction mechanisms aimed at achieving atomic precision in etching materials in the semiconductor industry. We discuss sequential reactions of surface passivation followed by directional low energy ion attack for ``volatile product'' removal to establish for what conditions self-limiting behavior required for Atomic Layer Etching (ALE) can be established using prototypical SiO2 -Si/fluorocarbon-Ar materials/etching systems. Second, studies of plasma-surface interactions related to application of a non-equilibrium atmospheric pressure plasma jet (APPJ) for modification of biomaterials are discussed. Changes in surface chemistry/biological activity of lipopolysaccharide (LPS) exposed to the APPJ plume/effluent in a controlled environment are reviewed. The results clarify how jet chemistry and interactions of plasma with the environment impact the consequences of APPJ-biomaterial-surface interactions. Based on collaborations with D. Metzler, S. Engelmann, R. Bruce, E. Joseph, E. Bartis, C. Hart, Q.-Y. Yang, J. Seog, T.-Y. Chung, H.-W. Chang, and D.B. Graves. We gratefully acknowledge funding from US Department of Energy (DE-SC0005105; DE-SC0001939) and National Science Foundation (CBET-1134273; PHY-1004256).

  19. Self-cleaning and antibiofouling enamel surface by slippery liquid-infused technique

    NASA Astrophysics Data System (ADS)

    Yin, Jiali; Mei, May Lei; Li, Quanli; Xia, Rong; Zhang, Zhihong; Chu, Chun Hung

    2016-05-01

    We aimed to create a slippery liquid-infused enamel surface with antibiofouling property to prevent dental biofilm/plaque formation. First, a micro/nanoporous enamel surface was obtained by 37% phosphoric acid etching. The surface was then functionalized by hydrophobic low-surface energy heptadecafluoro-1,1,2,2-tetra- hydrodecyltrichlorosilane. Subsequent infusion of fluorocarbon lubricants (Fluorinert FC-70) into the polyfluoroalkyl-silanized rough surface resulted in an enamel surface with slippery liquid-infused porous surface (SLIPS). The results of water contact angle measurement, diffuse-reflectance Fourier transform infrared spectroscopy, and atomic force microscope confirmed that the SLIPS was successfully constructed on the enamel surface. The antibiofouling property of the SLIPS was evaluated by the adsorption of salivary protein of mucin and Streptococcus mutans in vitro, as well as dental biofilm formation using a rabbit model in vivo. The results showed that the SLIPS on the enamel surface significantly inhibited mucin adhesion and S. mutans biofilm formation in vitro, and inhibited dental plaque formation in vivo.

  20. Is there any chlorine monoxide in the stratosphere?

    NASA Technical Reports Server (NTRS)

    Rogers, J. D.; Mumma, M. J.; Kostiuk, T.; Deming, D.; Hillman, J. J.; Faris, J.; Zipoy, D.

    1982-01-01

    A ground based search for the 856.50137/cm R(9.5) and for the 859.76765 R(12.5) transitions of stratospheric (Cl-35)O was made in the solar absorption mode using an infrared heterodyne spectrometer. Lines due to stratospheric HNO3 and tropospheric OCS were detected, at about 0.3% absorption levels. The expected lines of ClO in this same region were not detected, even though the optical depth of the ClO lines should be on the order of 0.2% using currently accepted ClO abundances. These infrared measurements suggest that stratospheric ClO is at least a factor of 7 less abundant than is indicated by indirect in situ fluorescence measurements, and the upper limit of 2.4x10 to the 13th power molecules/sq cm to the integrated column density of ClO is a factor of over 4 less than is indicted by microwave measurements. Results imply that the release of fluorocarbon precursors of ClO may be significantly less important for the destruction of stratospheric ozone than was previously thought.

  1. Designing superhydrophobic disordered arrays of fibers with hierarchical roughness and low-surface-energy

    NASA Astrophysics Data System (ADS)

    Rawal, Amit; Sharma, Sumit; Kumar, Vijay; Saraswat, Harshvardhan

    2016-12-01

    Hierarchical roughness and low surface energy are the main criteria for designing superhydrophobic surfaces with extreme water repellency. Herein, we present a step-wise approach to devise three-dimensional (3D) superhydrophobic disordered arrays of fibers in the form of nonwoven mats exhibiting hierarchical surface roughness and low surface energy. Key design parameters in the form of roughness factors at multiple length scales for 3D nonwoven mats have been quantified. The contact angles have been predicted for each of the wetting regimes that exists for nonwoven mats with predefined level of hierarchical surface roughness and surface energy. Experimental realization of superhydrophobic mats was attained by decorating the highly hydrophilic nonwoven viscose fibers with ZnO rods that effectively modulated the surface roughness at multiple length scales and subsequently, the surface energy was lowered using fluorocarbon treatment. Synergistic effects of hierarchical roughness and surface energy have systematically increased the static water contact angle of nonwoven mat (up to 164°) and simultaneously, lowered the roll-off angle (≈11°).

  2. 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.

  3. Electron Impact Ionization of C_2F_6

    NASA Astrophysics Data System (ADS)

    Iga, Ione; Pereira Sanches, Ivana; Srivastava, Santosh Kumar

    2001-10-01

    Besides CF_4, perfluoroethane, C_2F_6, is also one of the fluorocarbon compounds most frequently used in plasma processing applications. Consequently, the knowledge of the ionization properties of C_2F6 is clearly of interest in order to model the plasma-chemical reactions. Nevertheless, only few partial ionization-cross-section measurements [1,2] for this molecule were reported in the literature. Also, the energy range covered in these studies was very limited (below 120 eV). Recently, we have studied these properties. More specifically, partial ionization cross sections (PICS) for the fragments: C^+, F^+, CF^+, CF_2^+, CF_3^+ and C_2F_5^+, produced by electron impact on C_2F_6, were measured in a single-collision condition from near ionization threshold to 1000 eV. In addition, total ionization cross sections (TICS) are also obtained by summing up the PICS's. The comparison of our measured PICS and derived TICS with available data [1-4] will be presented during the Conference. [1] H. U. Poll, J. Meischner, Contrib. Plasma Phys. 27 (1987) 359. [2] C. Q. Jiao, A Garscadden, P. D. Haaland, Chem. Phys. Lett. 310 (1999) 52. [3] H. Nishimura, W. M. Huo, M. A Ali and Y -K. Kim, J. Chem. Phys. 110 (1999) 3811. [4] L. G. Christophorou and J. K. Olthoff, J. Phys. Chem. Ref. Data 27 (1998) 1 and references therein.

  4. The comparison of sample preparation techniques for the determination of technetium-99 in pure uranium compounds and subsequent analysis by inductively coupled plasma-mass spectrometry (ICP-MS)

    SciTech Connect

    Makinson, P.R.

    1995-12-31

    In this presentation, a procedure for the determination of ng/g levels of technetium-99 in uranium dioxide powder, hydrolyzed uranium hexafluoride (Hex), and uranyl nitrate liquor (UNL) is discussed, and three methods for the dissolution of uranium dioxide are compared. Digestion of uranium dioxide using concentrated nitric acid in a stoppered glass tube gives variable results. A concentrated hydrochloric acid dissolution using microwave digestion in sealed TFE-fluorocarbon PFA digestion vessels gives reproducible results, as does the digestion using dilute nitric acid in open beakers. The effects of the isobaric interference of ruthenium-99 and the molecular interference of {sup 98}MoH and the use of suitable algorithms to correct for such interferences are discussed. Compensation of signal suppression due to the uranium matrix is made by the use of matrix-matched calibration standard solutions and instrumental drift is monitored and corrected by the addition of rhodium as an internal standard. A detection limit (2 s) of 0.3 ng g{sup {minus}1} U is achieved using a solution containing 2 g of uranium per liter and a 30-s per isotope acquisition time, using peak jump mode.

  5. Theoretical study of the reactions M(+)+CH(3)F (M=Ge, As, Se, Sb).

    PubMed

    Méndez, Oscar; Colmenares, Fernando

    2010-06-21

    CASSCF-MRMP2 calculations have been carried out to analyze the reactions of the methyl fluoride molecule with the atomic ions Ge(+), As(+), Se(+) and Sb(+). For these interactions, potential energy curves for the low-lying electronic states were calculated for different approaching modes of the fragments. Particularly, those channels leading to C-H and C--F oxidative addition products, H(2)FC-M-H(+) and H(3)C-M-F(+), respectively were explored, as well as the paths which evolve to the abstraction (M-F(+)+CH(3)) and the elimination (CH(2)M(+)+HF) asymptotes. For the reaction Ge(+)+CH(3)F the only favorable channel leads to fluorine abstraction by the ion. As(+) and Sb(+) can react with CH(3)F along pathways yielding stable addition products. However, a viable path joining the oxidative addition product H(3)C-M-F(+) with the elimination asymptote CH(2)M(+)+HF was found for the reaction of the fluorocarbon compound with As(+). No favorable channels were detected for the interaction of fluoromethane with Se(+). The results discussed herein allow rationalizing some of the experimental data found for these interactions through gas-phase mass spectrometry.

  6. Wet ashing in biological samples in a microwave oven under pressure using poly(tetrafluoroethylene) vessels

    SciTech Connect

    Aysola, P.; Anderson, P.; Langford, C.H.

    1987-06-01

    Gorsuch has described the problems associated with the oxidation of organic matter in biological samples. This is a step that must precede trace metal determination by atomic spectroscopy. Treatment with acid on a hot plate typically requires 1-2 h. The use of a microwave oven is an attractive possibility for acceleration of the process. Koirtyohann et al. and Barrett et al. modified microwave ovens by adding an exhaust port. Nadkarni exploited an unmodified oven by using a Pyrex vacuum desiccator as a pressurizable vessel. They report significant losses of Cu (26%) and Pb (20%). Matts et al. tried polycarbonate pressurizable vessels, but the plastic quickly became opaque and brittle. The authors have reevaluated the prospects for use of an unmodified microwave oven with pressurized vessels. They found that Pyrex vessels gain heat in the glass quickly. The authors substituted Teflon TFA brand fluorocarbon resin for polycarbonate and find it has superior chemical and mechanical properties. They now report a 60-s pressure vessel procedure using an unmodified commercial oven.

  7. Failure analysis of the lithium battery: A study of the header deposit on the cell top and diffusion within the electrode glass seal using nuclear microanalysis and FFTIR spectroscopy

    NASA Astrophysics Data System (ADS)

    Hassan, Razi A.

    1991-10-01

    The Solid Rocket Booster Range Safety System (SRBRSS) uses a lithium/poly-carbon monofluoride primary battery as a source of electrical power. After cell fabrication and activation, some battery cells have shown self discharge. One possible source of this cell discharge has been suggested to be the formation and growth of a conducting crystallized chemical compound across the glass bead insulator, electrically shorting the glass bead to the casing. This laboratory has begun an analysis of this compound, the glass seal holding the cathode into place, and the cell electrolyte, using Fast Fourier Transform Infrared (FFTIR) Analysis, Rutherford Backscattering Spectroscopy (RBS), and Nuclear Reaction Microanalysis. Preliminary measurements have confirmed the existence of lithium, nitrogen, fluorine, and oxygen on a reddish-brown deposit covering parts of the glass seal holding the positive electrode in place. Cells using Li metal electrodes, have many advantages over conventional primary batteries. One principal disadvantage of using Li batteries on a commercial basis would be the environmental impact of the fluorocarbon material. Another would be the relatively high expense of (CF)n.

  8. Examination of fluorination effect on physical properties of saturated long-chain alcohols by DSC and Langmuir monolayer.

    PubMed

    Nakahara, Hiromichi; Nakamura, Shohei; Okahashi, Yoshinori; Kitaguchi, Daisuke; Kawabata, Noritake; Sakamoto, Seiichi; Shibata, Osamu

    2013-02-01

    Partially fluorinated long-chain alcohols have been newly synthesized from a radical reaction, which is followed by a reductive reaction. The fluorinated alcohols have been investigated by differential scanning calorimetry (DSC) and compression isotherms in a Langmuir monolayer state. Their melting points increase with an increase in chain length due to elongation of methylene groups. However, the melting points for the alcohols containing shorter fluorinated moieties are lower than those for the typical hydrogenated fatty alcohols. Using the Langmuir monolayer technique, surface pressure (π)-molecular area (A) and surface potential (ΔV)-A isotherms of monolayers of the fluorinated alcohols have been measured in the temperature range from 281.2 to 303.2K. In addition, a compressibility modulus (Cs(-1)) is calculated from the π-A isotherms. Four kinds of the alcohol monolayers show a phase transition (π(eq)) from a disordered to an ordered state upon lateral compression. The π(eq) values increase linearly with increasing temperatures. A slope of π(eq) against temperature for the alcohols with shorter fluorocarbons is unexpectedly larger than that for the corresponding fatty alcohols. Generally, fluorinated amphiphiles have a greater thermal stability (or resistance), which is a characteristic of highly fluorinated or perfluorinated compounds. Herein, however, the alcohols containing perfluorobutylated and perfluorohexylated chains show the irregular thermal behavior in both the solid and monolayer states.

  9. 2H,3H-decafluoropentane-based nanodroplets: new perspectives for oxygen delivery to hypoxic cutaneous tissues.

    PubMed

    Prato, Mauro; Magnetto, Chiara; Jose, Jithin; Khadjavi, Amina; Cavallo, Federica; Quaglino, Elena; Panariti, Alice; Rivolta, Ilaria; Benintende, Emilio; Varetto, Gianfranco; Argenziano, Monica; Troia, Adriano; Cavalli, Roberta; Guiot, Caterina

    2015-01-01

    Perfluoropentane (PFP)-based oxygen-loaded nanobubbles (OLNBs) were previously proposed as adjuvant therapeutic tools for pathologies of different etiology sharing hypoxia as a common feature, including cancer, infection, and autoimmunity. Here we introduce a new platform of oxygen nanocarriers, based on 2H,3H-decafluoropentane (DFP) as core fluorocarbon. These new nanocarriers have been named oxygen-loaded nanodroplets (OLNDs) since DFP is liquid at body temperature, unlike gaseous PFP. Dextran-shelled OLNDs, available either in liquid or gel formulations, display spherical morphology, ~600 nm diameters, anionic charge, good oxygen carrying capacity, and no toxic effects on human keratinocytes after cell internalization. In vitro OLNDs result more effective in releasing oxygen to hypoxic environments than former OLNBs, as demonstrated by analysis through oxymetry. In vivo, OLNDs effectively enhance oxy-hemoglobin levels, as emerged from investigation by photoacoustic imaging. Interestingly, ultrasound (US) treatment further improves transdermal oxygen release from OLNDs. Taken together, these data suggest that US-activated, DFP-based OLNDs might be innovative, suitable and cost-effective devices to topically treat hypoxia-associated pathologies of the cutaneous tissues.

  10. Durability of polymeric materials used in zinc/bromine flow batteries

    NASA Astrophysics Data System (ADS)

    Arnold, C., Jr.

    The lifetimes of zinc/bromine flow batteries may be limited by the durability of components which are fabricated from thermoplastic materials and exposed to the bromine-containing electrolyte. Examples of such components are flowframes and carbon-filled plastic electrodes. In early versions of the zinc/bromine battery, flowframes and electrodes were made from polypropylene and copolymers of propylene and ethylene. In later versions of the zinc/bromine battery, polyvinyl chloride (PVC) was used as the material to fabricate flowframes and polyethylene was used as the material used to fabricate both flowframes and electrodes. We found that carbon-plastic electrodes made from polypropylene or polypropylene rich copolymers were swelled and chemically attacked by the bromine-containing electrolytes. As a result, warpage occurred and the battery failed. On the basis of accelerated aging studies we estimated the lifetimes of the electrode and its polypropylene based component to be 96 and 10 months, respectively. The enhanced stability of the electrode was attributed to the presence of carbon which is known to be an antioxidant for thermoxidation. In accelerated exposure tests, bromine-containing electrolytes were also found to attack and leach out the additives used in PVC flowframes. PVC itself was only slightly degraded by the electrolyte. A commercial fluorocarbon, Tefzel, which contains no additives, was determined to be stable in bromine-containing electrolytes and is recommended as a replacement for PVC. Currently, aging studies on carbon-filled polyethylene electrodes are in progress.

  11. Development and characterization of new 157-nm photoresists based on advanced fluorinated polymers

    NASA Astrophysics Data System (ADS)

    Yamazaki, Tamio; Furukawa, Takamitsu; Itani, Toshiro; Ishikawa, Takuji; Koh, Meiten; Araki, Takayuki; Toriumi, Minoru; Kodani, T.; Aoyama, Hirokazu; Yamashita, Tsuneo

    2003-06-01

    Fluorinated polymers show a good transparency at the 157-nm exposure wavelength for single-layer resists. We have developed fluorinated resist polymers for 157-nm lithography. These polymers are main-chain fluorinated polymers synthesized by the co-polymerization of tetrafluoroethylene (TFE) and polymers such as poly(TFE/norbornene/α-fluoroolefin) fluoropolymers (FP1). In this paper, a number of polymerization initiators were evaluated in the polymerization of PF1-type polymers in order to investigate the effect of polymer end groups on optical and dissolution properties. We found that the polymer end group greatly affects the dissolution properties of these polymers when using a standard 0.26N tetramethylammonium hydroxide (TMAH) aqueous developer solution. These end groups also affect the polymer transparencies at 157-nm, and the resulting lithographic performance. The fluorocarbon initiator named "F2" induced the lowered absorbance (~0.4μm-1) and an increase in the dissolution rate (~300 nm/sec) without noticeable amounts of swelling. These polymer-based resists can achieve a resolution of less than 60-nm using a 157-nm laser microstepper (NA=0.85) with a Levenson-type strong phase shifting mask.

  12. Study and development of a cryogenic heat exchanger for life support systems

    NASA Technical Reports Server (NTRS)

    Soliman, M. M.

    1973-01-01

    A prototype cryogenic heat exchanger for removal of waste heat from a spacecraft environmental control life support system was developed. The heat exchanger uses the heat sink capabilities of the cryogenic propellants and, hence, can operate over all mission phases from prelaunch to orbit, to post landing, with quiescent periods during orbit. A survey of candidate warm fluids resulted in the selection of E-2, a fluorocarbon compound, because of its low freezing point and high boiling point. The final design and testing of the heat exchanger was carried out, however, using Freon-21, which is similar to E-2 except for its low boiling point. This change was motivated by the desire for cost effectiveness of the experimental program. The transient performance of the heat exchanger was demonstrated by an analog simulation of the heat sink system. Under the realistic transient heat load conditions (20 sec ramp from minimum to maximum Freon-21 inlet temperature), the control system was able to maintain the warm fluid outlet temperature within + or - 3 F. For a 20-sec ramp from 0 F to -400 F in the hydrogen inlet temperature, at maximum heat load, the warm fluid outlet temperature was maintained within + or - 7 F.

  13. Two episodes of acute illness in a machine shop

    SciTech Connect

    Sinks, T.; Kerndt, P.R.; Wallingford, K.M.

    1989-08-01

    Following an explosion in a machine shop and temporary plant closure, on the day the plant returned to full operations a degreaser malfunctioned. Workers in the assembly room were exposed to trichloroethylene levels later estimated to have exceeded 220 ppm (OSHA PEL 100 ppm). The plant was evacuated and the degreaser taken out of operation. Blood testing for carbon monoxide (CO) on five employees found carboxyhemoglobin levels in excess of normal. The plant reopened the following morning. Over the next two weeks, 15 employees were seen by the plant nurses for similar complaints; although all returned to work, their carboxyhemoglobin levels, later found to be inaccurate, were reported by a local medical clinic to range from 13.7 to 20.0 percent. At the end of the second week, another outbreak of illness occurred, but carboxyhemoglobin, trichloroethylene, fluorocarbons, and methylene chloride were not elevated in all 17 persons tested; plant-wide monitoring for CO found no elevated levels. During the first outbreak of illness, cases were 2.26 times as likely to have entered the assembly room as noncases. During the second outbreak, cases were no more likely than noncases to have entered the assembly room. We believe the explosion, earlier toxic exposures and illness, and the misleading blood test results led to plant-wide anxiety which culminated in a collective stress reaction and the second outbreak. An open meeting with all employees, informing them of our findings, provided reassurance and no further episodes of illness occurred in this workforce.

  14. Electron Beam Biasing of Substrates during Plasma Etching [1

    NASA Astrophysics Data System (ADS)

    Quick, A. K.; Hershkowitz, N.

    1997-10-01

    Electron beam biasing of substrates is being studied as an alternative to the usual method of using a capacitively coupled, rf-powered wafer chuck. The advantage of biasing with an electron beam is that the electrons which arrive at the wafer do so with an anisotropic velocity distribution similar to the plasma sheath-accelerated ions. This becomes important when etching large aspect ratio features. Isotropic plasma electrons can't follow the ions to the bottom of deep wells and they adhere to and charge up the feature sidewalls. This differential charging creates electric fields which deflect incoming ions and causes sidewall profile defects such as bowing, notching, and microtrenching and contributes to RIE(Reactive Ion Etch) lag( R. A. Gottscho, C. W. Jurgensen, and D. J. Vitkavage, J. Vac. Sci. Technol. B 10, Sep/Oct 1992, 2133.). The effects of etching sub-half micron nested poly-Silicon lines in Cl2 plasmas in the presence of an electron beam will be presented particularly in regard to notch suppression. The effects that the electron beam has on RIE lag suppression in SiO2 etching in fluorocarbon plasmas will also be discussed.

  15. Morphology-controlled synthesis of poly(oxyethylene)silicone or alkylsilicone surfactants with explicit, atomically defined, branched, hydrophobic tails.

    PubMed

    Gonzaga, Ferdinand; Grande, John B; Brook, Michael A

    2012-01-27

    Silicone surfactants are widely used in commerce because of the unusual surface activity when compared with fluorocarbon or hydrocarbon surfactants. However, most silicone surfactants are comprised of ill-defined mixtures, which preclude the development of an understanding of structure-surface activity relationships. Herein, we report a synthetic strategy that permits exquisite control over silicone structure by using the B(C(6)F(5))(3)-catalyzed condensation of hydro- and alkoxysilanes. Six different, precise hydrophobes were then mated to hydrophilic poly(oxyethylene)s of three different molecular weights by a metal-free click cyclization to generate a library of explicit silicone surfactants. These compounds were calculated to have a relatively linear value range of the hydrophilic-lipophilic balance, ranging from about 8 to about 15. The solubility of some of the compounds was too low to measure a critical micelle concentration (CMC). The others exhibited a broad range of surface tension values at the CMC that depend both on the length of the hydrophilic tail and, more importantly, the nature of the hydrophobic head group. Subtle distinctions in surfactant-related properties, which can be attributed to the three-dimensional structures, can be seen for compounds with comparable numbers of hydrocarbons and silicon groups.

  16. Transient Pressure Test Article (TPTA) 1.1 and 1.1A, volume 1

    NASA Technical Reports Server (NTRS)

    Rebells, Clarence A.

    1988-01-01

    This final test report presents the results obtained during the static hot firing and cold-gas high Q tests of the first Transient Pressure Test Article (TPTA) 1.1. The TPTA consisted of field test joints A and B, which were the original RSRM J-insulation configuration, with a metal capture feature. It also consisted of a flight configuration nozzle-to-case test joint (Joint D) with shorter vent slots. Fluorocarbon O-rings were used in all the test joints. The purpose of the TPTA tests is to evaluate and characterize the RSMR field and nozzle-to-case joints under the influence of ignition and strut loads during liftoff anf high Q. All objectives of the cold-gas high Q (TPTA 1.1A) test were met and all measurements were close to predicted values. During the static hot-firing test (TPTA 1.1), the motor was inadvertently plugged by the quench injector plug, making it a more severe test, although no strut loads were applied. The motor was depressurized after approximately 11 min using an auxiliary system, and no anomalies were noted. In the static hot-firing test, pressure was incident on the insulation and the test joint gaps were within the predicted range. During the static hot-firing test, no strut loads were applied because the loading system malfunctioned. For this test, all measurements were within range of similar tests performed without strut loads.

  17. Surface-catalyzed air oxidation of hydrazines: Environmental chamber studies

    NASA Technical Reports Server (NTRS)

    Kilduff, Jan E.; Davis, Dennis D.; Koontz, Steven L.

    1988-01-01

    The surface-catalyzed air oxidation reactions of fuel hydrazines were studied in a 6500-liter fluorocarbon-film chamber at 80 to 100 ppm concentrations. First-order rate constants for the reactions catalyzed by aluminum, water-damaged aluminum (Al/Al2O3), stainless steel 304L, galvanized steel and titanium plates with surface areas of 2 to 24 sq m were determined. With 23.8 sq m of Al/Al2O3 the surface-catalyzed air oxidation of hydrazine had a half-life of 2 hours, diimide (N2H2) was observed as an intermediate and traces of ammonia were present in the final product mixture. The Al/Al2O3 catalyzed oxidation of monomethylhydrazine yielded methyldiazine (HN = NCH3) as an intermediate and traces of methanol. Unsymmetrical dimethylhydrazine gave no detectable products. The relative reactivities of hydrazine, MMH and UDMH were 130 : 7.3 : 1.0, respectively. The rate constants for Al/Al2O3-catalyzed oxidation of hydrazine and MMH were proportional to the square of the surface area of the plates. Mechanisms for the surface-catalyzed oxidation of hydrazine and diimide and the formation of ammonia are proposed.

  18. Micromachining of transparent materials by laser ablation of organic solution

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Niino, Hiroyuki; Yabe, Akira

    2000-11-01

    Transparent materials such as fused silica, quartz, calcium fluoride, and fluorocarbon polymer were etched upon irradiation of organic solution containing pyrene with a conventional KrF excimer laser. Threshold fluence for etching was 240 mJ/cm2 for fused silica. Etch rate remarkably depended on a concentration of pyrene: higher etch rate with the increase of pyrene concentration. It means that pyrene molecules play an important role in this process. The etch rate can be easily controlled through changing a laser pulse number, a laser fluence and a concentration of solution. The mechanism for this process is discussed by cyclic multiphotonic absorption of pyrene in the excited states, thermal relaxation, and formation of super-heated solution. As the results, it is suggested that the process is based on the combination of two processes in the interface between the transparent materials and the liquid: one is a heating process by a super-heated liquid and the other is an attacking process by a high temperature and pressure vapor.

  19. Development of the pellicle for KrF excimer laser photolithography

    NASA Astrophysics Data System (ADS)

    Shirasaki, Toru; Kawakami, S.; Hamada, Y.; Nagata, Y.; Kashida, Meguru; Kubota, Yoshihiro

    1994-11-01

    This paper describes development of the pellicle for KrF excimer laser photolithography. The components of KrF excimer pellicle should have high light resistance. Our pellicle membrane consists of amorphous perfluoropolymer. Since this material provides that scattering and absorption of light at deep-UV wavelength region are very small, transmissivity is high at that wavelength and light resistance is strong against KrF excimer laser. Membrane bond and reticle adhesive consist of silicone resin so that the light resistance of them is high. And the bond strength of our pellicle is very high despite the use of fluoro-polymer membrane. This is because the bond consists of silicone resin which contains fluorocarbon-group. Strict particle suppression is required for the excimer pellicle. We have covered the frame with UV resistant fluoropolymer for the purpose to reduce the possibility of particle generation. This treatment has suppressed the particle generation during transportation. Membrane cutting has been achieved by melt-cutting method. The prominency of this method is melting the membrane with heat and cutting it with no contact with pellicle frame, so that the membrane edge becomes smooth and pellicle frame has not been damaged.

  20. Preparation of hierarchical porous Zn-salt particles and their superhydrophobic performance

    NASA Astrophysics Data System (ADS)

    Gao, Dahai; Jia, Mengqiu

    2015-12-01

    Superhydrophobic surfaces arranged by hierarchical porous particles were prepared using modified hydrothermal routes under the effect of sodium citrate. Two particle samples were generated in the medium of hexamethylenetetramine (P1) and urea (P2), respectively. X-ray diffraction, scanning electron microscope, and transmission electron microscope were adopted for the investigation, and results revealed that the P1 and P2 particles are porous microspheres with crosslinked extremely thin (10-30 nm) sheet crystals composed of Zn5(OH)8Ac2·2H2O and Zn5(CO3)2(OH)6, respectively. The prepared particles were treated with a fluoroethylene vinyl ether derivative and studied using Fourier transform infrared spectroscopy and energy-dispersive X-ray spectrometer. Results showed that the hierarchical surfaces of these particles were combined with low-wettable fluorocarbon layers. Moreover, the fabricated surface composed of the prepared hierarchical particles displayed considerably high contact angles, indicating great superhydrophobicity for the products. The wetting behavior of the particles was analyzed with a theoretical wetting model in comparison with that of chestnut-like ZnO products obtained through a conventional hydrothermal route. Correspondingly, this study provided evidence that high roughness surface plays a great role in superhydrophobic behavior.

  1. 2H,3H-Decafluoropentane-Based Nanodroplets: New Perspectives for Oxygen Delivery to Hypoxic Cutaneous Tissues

    PubMed Central

    Jose, Jithin; Khadjavi, Amina; Cavallo, Federica; Quaglino, Elena; Panariti, Alice; Rivolta, Ilaria; Benintende, Emilio; Varetto, Gianfranco; Argenziano, Monica; Troia, Adriano; Cavalli, Roberta; Guiot, Caterina

    2015-01-01

    Perfluoropentane (PFP)-based oxygen-loaded nanobubbles (OLNBs) were previously proposed as adjuvant therapeutic tools for pathologies of different etiology sharing hypoxia as a common feature, including cancer, infection, and autoimmunity. Here we introduce a new platform of oxygen nanocarriers, based on 2H,3H-decafluoropentane (DFP) as core fluorocarbon. These new nanocarriers have been named oxygen-loaded nanodroplets (OLNDs) since DFP is liquid at body temperature, unlike gaseous PFP. Dextran-shelled OLNDs, available either in liquid or gel formulations, display spherical morphology, ~600 nm diameters, anionic charge, good oxygen carrying capacity, and no toxic effects on human keratinocytes after cell internalization. In vitro OLNDs result more effective in releasing oxygen to hypoxic environments than former OLNBs, as demonstrated by analysis through oxymetry. In vivo, OLNDs effectively enhance oxy-hemoglobin levels, as emerged from investigation by photoacoustic imaging. Interestingly, ultrasound (US) treatment further improves transdermal oxygen release from OLNDs. Taken together, these data suggest that US-activated, DFP-based OLNDs might be innovative, suitable and cost-effective devices to topically treat hypoxia-associated pathologies of the cutaneous tissues. PMID:25781463

  2. Shape transitions in supercritical CO2 microemulsions induced by hydrotropes.

    PubMed

    James, Craig; Hatzopoulos, Marios Hopkins; Yan, Ci; Smith, Gregory N; Alexander, Shirin; Rogers, Sarah E; Eastoe, Julian

    2014-01-14

    The ability to induce morphological transitions in water-in-oil (w/o) and water-in-CO2 (w/c) microemulsions stabilized by a trichain anionic surfactant 1,4-bis(neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2-sulfonate (TC14) with simple hydrotrope additives has been investigated. High-pressure small-angle neutron scattering (SANS) has revealed the addition of a small mole fraction of hydrotrope can yield a significant elongation in the microemulsion water droplets. For w/o systems, the degree of droplet growth was shown to be dependent on the water content, the hydrotrope mole fraction, and chemical structure, whereas for w/c microemulsions a similar, but less significant, effect was seen. The expected CO2 viscosity increase from such systems has been calculated and compared to related literature using fluorocarbon chain surfactants. This represents the first report of hydrotrope-induced morphology changes in w/c microemulsions and is a significant step forward toward the formation of hydrocarbon worm-like micellar assemblies in this industrially relevant solvent.

  3. Possible greenhouse effects of tetrafluoromethane and carbon dioxide emitted from aluminum production

    NASA Astrophysics Data System (ADS)

    Weston, Ralph E.

    Tetrafluoromethane (CF 4) is an extremely stable gas which strongly absorbs infrared radiation at ˜ 8 μm, and therefore is capable of influencing the greenhouse effect. No natural sources have been identified, and the major anthropogenic source appears to be the electrolytic smelting of alumina to produce aluminum. Measurements of CF 4 concentrations in the atmosphere are reviewed, and these are combined with aluminum production rates to provide an estimate of 1.3-3.6 kg of CF 4 emitted per ton of aluminum produced for the period up to ˜ 1985. Aluminum production also requires large amounts of electrical energy, leading to the emission of as much as 22 tons of carbon dioxide per ton of aluminum due to fossil fuel combustion in power plants. The present day contribution of hydroelectric power reduces this figure to about 14 tons of carbon dioxide per ton of aluminum. An estimate of the relative radiative trapping of CF 4 and CO 2 emitted in aluminum production during this same period (1900-1985) indicates that the effect of CF 4 is about one-third that of the CO 2 formed by aluminum production. However, the emission of fluorocarbons from modem aluminum electrolysis cells is much lower than previous estimates indicate, and this factor is considered in estimating potential long-term global warming effects of CF 4 and CO 2 from aluminum production. Possible processes leading to removal of CF 4 from the atmosphere are described.

  4. Photodetachment neutralizer development: Laser window design study: Volume 1, Summary: Final report

    SciTech Connect

    Not Available

    1984-09-30

    Photodetachment neutralization (PDN) has been proposed as a major improvement to the gas cell neutralization utilized on current neutral beam heating systems for magnetic containment fusion devices. This PDN system will use a Chemical Oxygen Iodine Laser (COIL) to produce a light beam with photons of a near optimal wavelength which can be reflected back and forth across the path of the ion beam to create the necessary high density light ''cloud'' required for the photodetachment process. In a fusion device the neutral beam goes directly into the process vacuum chamber and therefore the oxygen iodine gas mixture in the laser must be isolated by a window from the neutral beam channel without loss of too much light or leakage of miniscule quantities of laser gas. The aerodynamic windows that have traditionally been used with chemical lasers are viewed as undesirable for the fusion application where any contamination of the fusion vacuum chamber by laser gas would be a big problem. It was concluded that the technological issues were uncertain enough that a verification by designing, fabricating, and testing of a demonstration window would be required before feasibility of such a window could be considered certain. The statement of work defined for this study consisted of two tasks: determination of the absorption characteristics of the proposed sapphire window material and the fluorocarbon coolant, and design and analysis of the proposed double disk heat exchanger window and demonstration test hardware.

  5. Demonstration of heavy and light density populations of Aleutian disease virus.

    PubMed Central

    Cho, H J

    1977-01-01

    A highly purified and concentrated suspension of aleutian disease virus was prepared from large quantities of early infected mink tissues using repeated fluorocarbon extraction procedures. Equilibrium centrifugation of the aleutian disease virus preparation in a cesium chloride gradient yielded three distinct bands at buoyant densities of 1.295, 1.332, and 1.405--1.416 g/cm(3). Electron microscopic observations of these three bands revealed mainly empty particles in the first band. In the second band complete particles with a flattened appearnce predominated and there were also some empty particles. In the third band both complete and empty particles were observed. The size of the aleutian disease virus particles observed in all of the three densities was 23 nm. Light aleutian disease virions (density of 1.332 g/cm3) had a particle to counterimmunoelectrophoresis antigen ratio comparable to that of dense aleutian disease virions (density of 1.405--1.416 g/cm3) but possessed much lower infectivity as determined by mink inoculation. Images Fig. 1. Fig. 2. PMID:193625

  6. A conformal oxidation-resistant, plasma-polymerized coating

    NASA Technical Reports Server (NTRS)

    Golub, Morton A.; Wydeven, Theodore; Lerner, Narcinda R.

    1991-01-01

    A comparative study was made of the surface recession (etching) of thin films of plasma polymerized tetrafluoro ethylene (PPTFE), polytetrafluoro ethylene (PTFE), and ion-beam sputter deposited polytetrafluoro ethylene (SPTFE) exposed to ground-state atomic oxygen downstream from a nonequilibrium radio-frequency O2 plasma. At 22 C, the etch rates for PTFE, SPTFE, and PPTFE were in the ratio of 8.7:1.8:1.0. A thin, conformal coating of PPTFE (etch rate of 0.3 nm/h at 22 C) was found to protect an underlying cast film of a reactive polymer, cis-1,4 polybutadiene, against ground-state atomic oxygen attack for the time required to fully etch away the PPTFE coating. From ESCA analysis, PTFE exhibited only minor surface oxidation (uptake of 0.5 atom percent O) upon etching, its F/C ratio decreasing slightly from 2.00 to 1.97; PPTFE exhibited considerable surface oxidation (uptake of 5.9 atom percent O) intermediate between those of PTFE and PPTFE, with a decrease in F/C ratio from 1.73 to 1.67. A plasma-polymerized fluorocarbon coating such as PPTFE might be useful for space applications to protect polymers that are vulnerable to oxidation or degradation by oxygen atoms.

  7. Tuning Oleophobicity of Silicon Oxide Surfaces with Mixed Monolayers of Aliphatic and Fluorinated Alcohols.

    PubMed

    Lee, Austin W H; Gates, Byron D

    2016-12-13

    We demonstrate the formation of mixed monolayers derived from a microwave-assisted reaction of alcohols with silicon oxide surfaces in order to tune their surface oleophobicity. This simple, rapid method provides an opportunity to precisely tune the constituents of the monolayers. As a demonstration, we sought fluorinated alcohols and aliphatic alcohols as reagents to form monolayers from two distinct constituents for tuning the surface oleophobicity. The first aspect of this study sought to identify a fluorinated alcohol that formed monolayers with a relatively high surface coverage. It was determined that 1H,1H,2H,2H-perfluoro-1-octanol yielded high quality monolayers with a water contact angle (WCA) value of ∼110° and contact angle values of ∼80° with toluene and hexadecane exhibiting both an excellent hydrophobicity and oleophobicity. Tuning of the oleophobicity of the modified silicon oxide surfaces was achieved by controlling the molar ratio of 1H,1H,2H,2H-perfluoro-1-octanol within the reaction mixtures. Surface oleophobicity progressively decreased with a decrease in the fluorinated alcohol content while the monolayers maintained their hydrophobicity with WCA values of ∼110°. The simple and reliable approach to preparing monolayers of a tuned composition that is described in this article can be utilized to control the fluorocarbon content of the hydrophobic monolayers on silicon oxide surfaces.

  8. 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.

    1994-01-01

    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 HO(sub x) and NO(sub x) 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 HO2 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. In this annual report, we focus on our recent accomplishments in the quantitative spectroscopy of the HO2 radical. This report details the measurements of the broadening coefficients for the v(sub 2) vibrational band. Further measurements of the vapor pressures of nitric acid hydrates relevant to the polar stratospheric cloud formation indicate the importance of metastable crystalline phases of H2SO4, HNO3, and H2O. Large particles produced from these metastable phases may provide a removal mechanism for HNO3 in the polar stratosphere.

  9. The effect of cultureware surfaces on functional and structural components of differentiated 3T3-L1 preadipocytes.

    PubMed

    Pavlikova, Nela; Weiszenstein, Martin; Pala, Jan; Halada, Petr; Seda, Ondrej; Elkalaf, Moustafa; Trnka, Jan; Kovar, Jan; Polak, Jan

    2015-12-01

    Experiments using cultured primary cells or cell lines are a routine in vitro approach used across multiple biological disciplines, However, the structural and functional influences of various cultureware materials on cultured cells is not clearly understood. Surface treatments of cultureware have proven to have profound effects on cell viability and proliferation. In this study, we investigated the impact of polystyrene and fluorocarbon cultureware dishes on the proteomic profile of differentiated 3T3-L1 preadipocytes. After expansion and differentiation of cells on appropriate cultureware dishes, cell lysates were separated using two-dimensional gel electrophoresis and proteins were visualized with Coomassie blue staining. Spots with the highest differential expression between the two culture conditions were subsequently analyzed using matrix-assisted laser desorption/ionization mass spectrometry and the identified proteins were subjected to pathway analysis. We observed that 43% of all spots were differentially expressed depending on the cultureware. Pathway analysis revealed that glucose metabolism, mitochondrial structure and cell differentiation, represented by 14-3-3 protein-mediated signaling and the mitochondrial inner membrane organizing system (MINOS), were significantly affected by cultureware material. These results indicate that cultureware material can have a profound effect on key adipocyte functional pathways. These effects modifications of the cells should be reflected in the design of in vitro experiments and interpretation of their results.

  10. NMR at the Picomole Level of a DNA Adduct

    PubMed Central

    Kautz, Roger; Wang, Poguang; Giese, Roger W.

    2014-01-01

    We investigate the limit of detection for obtaining NMR data of a DNA adduct using modern microscale NMR instrumentation, once the adduct has been isolated at the pmol level. Eighty nanograms (130 pmol) of a DNA adduct standard, N-(2′-deoxyguanosin-8-yl)-2-acetylaminofluorene 5′-monophosphate (AAF-dGMP), in 1.5 μL of D2O with 10% methanol-d4, in a vial, was completely picked up as a droplet suspended in a fluorocarbon liquid, and loaded efficiently into a microcoil probe. This work demonstrates a practical manual method of droplet microfluidic sample loading, previously demonstrated using automated equipment, which provides a several-fold advantage over conventional flow injection. Eliminating dilution during injection and confining the sample into the observed volume realizes the full theoretical mass sensitivity of a microcoil, comparable to a micro-cryo probe. With 80 ng, an NMR spectrum acquired over 40 hr showed all of the resonances seen in a standard spectrum of AAF-dGMP, with a S/N of at least 10, despite broadening due to previously-noted effects of conformational exchange. Also a 2D TOCSY spectrum (total correlation spectroscopy) was acquired on 1.6 μg in 18 hr. This work helps to define the utility of NMR in combination with other analytical methods for the structural characterization of a small amount of a DNA adduct. PMID:24028148

  11. Adsorption of fluorinated ethers and alcohols on fresh and oxidized carbon overcoats for magnetic data storage.

    PubMed

    Yun, Yang; Broitman, Esteban; Gellman, Andrew J

    2007-02-13

    Temperature programmed desorption has been used to study the desorption kinetics and desorption energies of perfluorodiethylether, (CF3CF2)2O, and 2,2,2-trifluoroethanol, CF3CH2OH, adsorbed on fresh and oxidized hydrogenated amorphous carbon (a-CHx) films. (CF3CF2)2O and CF3CH2OH serve as models for the ether backbone and hydroxyl end-groups of Fomblin Zdol, the lubricant most commonly used to lubricate the surfaces of amorphous carbon overcoats on magnetic data storage hard disks. Our measurements clearly reveal, for the first time, the effects of surface oxidation on the adsorption of fluorocarbon lubricants such as Fomblin Zdol on a-CHx films. Oxidation of the a-CHx surface increases the desorption energy of CF3CH2OH but has no observable impact on the desorption energy of (CF3CF2)2O. These results support the suggestion that the alcohols interact with the surface via hydrogen bonding. From a practical perspective, these results imply that the oxidation of the fresh a-CHx film may serve as a means to control or tailor the a-CHx surface to optimize the properties of the lubricant-overcoat interface in hard disks.

  12. Ultra-rapid plasma freezing with halocarbon heat transfer liquids

    SciTech Connect

    Coelho, P.H.; Comerchero, V.

    1988-03-15

    A process of freezing plasma is described comprising the steps of exposing thin wall containers of plasma to be frozen to direct contact with a heat transfer liquid selected from the group consisting of the chlorofluorocarbon 1,1,2 trichloro-1,2,2, trifluoro-ethane (CFC 113) and mixtures of the chlorofluorocarbon 1,1,2 trichloro-1,2,2, trifluoro-ethane (Freon 113) and at least one of the fluorocarbons perfluoropentane (C/sub 5/F/sub 12/), perfluorohexane (C/sub 6/F/sub 14/), perfluoromethylcyclohexane (C/sub 7/F/sub 14/), perfluoroheptane (C/sub 7/F/sub 16/), perfluoromonomethyldimethylcyclohexanes (C/sub 7/F/sub 14/C/sub 8/F/sub 16/), perfluorodecalin isomers (C/sub 10/F/sub 18/), mixed perfluorodecalin and methyldecalin isomers (C/sub 10/F/sub 18/+C/sub 11/F/sub 20/), and perfluorinatd polyethers ((OCF(CF/sub 3/)CF/sub 2/)/sub n/ - (OCF/sub 2/)/sub m/, and maintaining the liquid at a temperature sufficiently low enough to freeze the plasma in the desired amount of time.

  13. A comparison of adsorbed and grafted fibronectin coatings under static and dynamic conditions.

    PubMed

    Montaño-Machado, Vanessa; Hugoni, Ludivine; Díaz-Rodríguez, Sergio; Tolouei, Ranna; Chevallier, Pascale; Pauthe, Emmanuel; Mantovani, Diego

    2016-09-21

    Coatings for medical devices are expected to improve their surface biocompatibility mainly by being bioactive, i.e. stimulating healing-oriented interactions with living cells, tissues and organs. In particular, for stent applications, coatings are often designed to enhance the endothelialization process. The coating strategy will be primarily responsible for the interfacial properties between the substrate and the coating, which must show high stability. Therefore, the present work aims at comparing the stability of adsorbed and grafted fibronectin, a protein well-known to promote endothelialization. Fibronectin coatings were deposited on fluorocarbon films generated by a plasma-based process on stainless steel substrates. Then, deformation tests were performed in order to simulate the stenting procedure and stability tests were completed under static and under-flow conditions. Coatings were characterized by XPS, AFM, water contact angle, immunostaining and ToF-SIMS analyses. The results show higher stability for the grafted coatings; indeed, the integrity of the protein simply adsorbed was strongly compromised especially after under-flow tests. Both coatings exhibited similar behavior after deformation and static tests. These results clearly show the impact of the coating strategy on the overall stability of the coatings as well as the importance of under-flow investigations.

  14. Sharp Interface Level Set Method based Study for Evaporation of a Sessile Droplet on Hydrophilic and Hydrophobic Substrates

    NASA Astrophysics Data System (ADS)

    Shaikh, Javed; Sharma, Atul; Bhardwaj, Rajneesh

    2016-11-01

    The evaporation of a sessile droplet is important in many applications like hot-spot cooling, surface patterning etc. An understanding of the droplet dynamics in terms of evaporation rate, evaporative cooling and substrate wettability is important for designing the droplet based devices. Extensive theoretical and experimental research has been conducted on evaporating droplets in recent years; however, the effect of surrounding vapors on the evaporation dynamics of a sessile droplet is not found in the literature. In this work, an in-house sharp-interface level set code based on the Ghost Fluid Method (GFM) is used. Energy, species, and momentum equations are coupled for studying the sessile droplet evaporation phenomenon on hydrophilic and hydrophobic substrates. Different modes of droplet evaporation i.e. constant contact radius (CCR), constant contact angle (CCA) are observed for the two types of substrates. The coupling of energy and species equations is used for capturing the evaporating cooling induced dip in the droplet surface temperature. The effect of surrounding vapors like fluorocarbon vapors, on the evaporative cooling, is presented for water droplet on the hydrophilic and hydrophobic substrates. Research Scholar.

  15. Equipment and design changes in extrusion of foamed fluoropolymer resins

    NASA Astrophysics Data System (ADS)

    Randa, S. K.; Carlson, M. A.; Reifschneider, D. P.

    Recent growth of computer networks has increased the market for foamed coaxial cables. To meet this need, the gas injection process for foaming of Teflon* FEP and PFA fluorocarbon resins introduced in 1981 at the 30th Wire and Cable Symposium has been refined. Advances in die and extruder screw design have broadened capability from 500 CATV coaxial cable to miniature wire sizes. Increased processing speeds and higher core quality have been achieved. These coaxial cables have a unique combination of properties that are maintained over a wide range of temperatures and signal frequencies. They have dielectric constants as low as 1.3 and low flame spread and smoke generation as tested to UL 910. These cables are now widely used for high frequency signal transmission in compliance with the National Electric Code for installation without conduit in building air handling plenums. Military applications represent newer areas of interest with weight and space savings and high electrical quality. The characteristics of several coaxial cables are reviewed.

  16. Surface tension measurement techniques of magnetic fluids at an interface between different fluids using perpendicular field instability

    NASA Astrophysics Data System (ADS)

    Amin, M. Shahrooz; Elborai, Shihab; Lee, Se-Hee; He, Xiaowei; Zahn, Markus

    2005-05-01

    Two measurement techniques to determine the surface tension of ferrofluids using the perpendicular field instability are described. Four ferrofluid layers were examined with magnetic field applied perpendicularly to the surface of (1) oil-based ferrofluid in air; (2) water-based ferrofluid in air, (3) oil-based ferrofluid, and (4) fluorocarbon-based ferrofluid, both below a blend of 50% n-Propyl alcohol and 50% deionized water (propanol). Surface tension was accurately calculated by utilizing the measured Taylor wavelength from measurements of incipient fluid instability peaks and the measured densities of fluids. For cases (1) and (2), the calculated surface tension values were in good agreement with a tensiometer measurement. No accurate tensiometer measurements were conducted for the superposed liquids (3) and (4) since accurate tensiometer measurements are difficult for a two fluid layer system. The second less accurate method used the ferrofluid's nonlinear Langevin magnetization characteristics to compute the surface tension from incipience of interfacial instability conditions. Discrepancies between the surface tensions measured by the two methods were probably due to the ferrofluid particle size distributions and the strong dependence of the ferrofluid magnetization on particle size.

  17. A Roof for the Lions' House

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Fans of the National Football League s Detroit Lions don't worry about game day 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.The team of DuPont, Chemical Fabrics and Birdair have collaborated on a number of fabric structures. Some are supported by air pressure, others by cables alone. Most of the structures are in the recreational category. With conventional construction costs still on the upswing, you're likely to see a great many more permanent facilities enclosed by the aerospace spinoff fabric.

  18. 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.

  19. MEMS-compatible Integrated Hollow Waveguides Fabricated by Buckling Self-assembly

    NASA Astrophysics Data System (ADS)

    Epp, Eric Richard

    This thesis describes the fabrication and characterization of integrated hollow Bragg waveguides fabricated by controlled thin film buckling. Hollow waveguides based on two different set of materials were studied. In the first case, thermal tuning of air-core dimensions was studied using waveguides, with chalcogenide glass and polymer claddings. Results showed that the change in air-core height as a function of small temperature variations was in good agreement with theory. Planar, silicon based, hollow core waveguides with Si/SiO2 Bragg reflector claddings are also described. Fabrication was accomplished by incorporating compressive stress in the sputtered Si and SiO2 layers and then heating samples to induce buckling along predefined areas of low adhesion. Several low adhesion layers were studied, but a fluorocarbon layer was deposited by CVD gave the best results. Optical experiments demonstrated optical confinement in the air-core, with loss in the 5 dB/cm range at the 1550 nm wavelength.

  20. Wetting of topological nano-patterned surfaces

    NASA Astrophysics Data System (ADS)

    Gang, O.; Alvine, K.; Black, C. T.

    2005-03-01

    We have investigated the evolution of simple hydrocarbon and fluorocarbon liquid films on nano-patterned surfaces of near-hexagonally packed 20 nm wide nano-cavities [1]. Our x-ray measurements show that the behavior of wetting films on patterned surfaces differs from the expected δμ-1/3 dependence found for the van der Waals interacting flat films [2]. Two different regimes (filling and growing) for the wetting film evolution were observed as a function of the chemical potential offset δμ. The filling regime exhibits a δμ-3/4 dependence for the adsorption of the liquid film into nanocavity; a significant enhancement compared to the flat surface. These results qualitatively confirm the theoretically predicted increase of the wetting exponent for the curved surface. However, quantitatively, the measured exponent for the paraboloid-like cavity is considerably lower than the predicted value [3]. *C. T. Black et al, Appl. Phys. Lett., 79, 409, (2001). *O. Gang et al, M. Fukuto, P.Huber, P.Pershan, Coll. and Surf. A 206, 293, 2002 *Rascon, C. and A.O. Parry, Nature, 407: p. 986 (2000); Robbins, M.O et al Phys. Rev. A, 43(8), 4344 (1991).