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1

Fluorocarbon Triazine Polymers.  

National Technical Information Service (NTIS)

Linear fluorocarbon triazine containing polymers are prepared by reacting a fluorocarbon nitrile with ammonia and silver trifluoroacetate, and reacting the resulting silver chelate with a fluorocarbon acid anhydride to provide a triazine product. The tria...

W. R. Griffin

1977-01-01

2

PRODUCTION OF FLUOROCARBONS  

DOEpatents

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.

Sarsfield, N.F.

1949-06-21

3

Determination of fluorocarbon in blood.  

PubMed

Because fluorocarbons can dissolve relatively large quantities of oxygen and carbon dioxide, there is considerable interest in utilizing them to develop new methods of extracorporael circulation, artificial red blood cells, and liquid breathing techniques. A method for the assay of fluorocarbon in blood is presented. The fluorocarbon is extracted from the blood with toluene, and fluoride is released from the fluorocarbon in the toluene extract by reaction with sodium biphenyl. The inorganic fluoride is then extracted with aqueous sodium acetate, the pH of the extract is adjusted, and the activity of the fluoride ion is read with a fluoride-specific ion electrode. The assay was effective for fluorocarbon concentrations in the range of 1 to 30 ppm. PMID:1176521

Stein, T P; Robbins, W K; Brooks, H B; Wallace, H W

1975-09-01

4

Fluorocarbon emulsions--the stability issue.  

PubMed

Long-term room temperature stability of ready-to-use concentrated fluorocarbon emulsions is necessary in order to fully exploit the therapeutic potential of fluorocarbons. Consequently, considerable efforts have been directed at investigating the physical nature of such emulsions, the mechanisms which lead to their degradation and the means of counteracting these. The particles which constitute typical fluorocarbon/egg yolk phospholipid emulsions have been identified to be surfactant-coated fluorocarbon droplets and lipid vesicles. Better understanding has been gained on the formation, structure and evolution of these particles during processing and storage. This has led to optimized formulations and processing, better control of emulsion characteristics and significantly improved stability. Molecular diffusion (Ostwald ripening or transcondensation) has been shown to be the maun mechanism of degradation when particles are less than 1 micron in diameter, even for the highly concentrated (volume fraction of fluorocarbon up to 50%) second generation fluorocarbon emulsions. Significant emulsion stabilization has been accomplished by adding fluorochemicals which are both less volatile and less water soluble, and nevertheless have an organ dwell time acceptable for intravascular use. The rate of molecular diffusion can also be reduced by decreasing the fluorocarbon/water interfacial tension; this was effectively achieved with appropriate, well-defined fluorinated surfactants. A further, novel means of stabilizing fluorocarbon-in-water emulsions makes use of mixed fluorocarbon-hydrocarbon amphiphiles which act as molecular dowels to reinforce the adhesion between the fluorocarbon phase and the lipophilic zone of the surfactant film. Both long-term room temperature stability, and particle-size control over a large range of diameter, have been achieved by applying this principle. All in all it can be said that the challenge of producing injectable fluorocarbon emulsions with long-term room temperature particle size stability has been met. PMID:7849970

Postel, M; Riess, J G; Weers, J G

1994-01-01

5

Fluorinated diamond bonded in fluorocarbon resin  

DOEpatents

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.

Taylor, Gene W. (Los Alamos, NM)

1982-01-01

6

Lubrication and Physical Properties of Fluorocarbon Fluids.  

National Technical Information Service (NTIS)

Nine fluorocarbon fluids representing four classes of fluorinated organic liquids were compared with the base fluids for the present specification weapons lubricants. Wear, friction, load-carrying capacity, and physical property data show that several of ...

G. P. Murphy C. J. Quilty

1969-01-01

7

Electron attachment to fluorocarbon radicals  

NASA Astrophysics Data System (ADS)

Thermal electron attachment rate constants for a series of small fluorocarbon radicals (CF2, C2F3, 1-C3F7, 2-C3F7, C3F5, CF3O) were measured from 300 to 600 K using the variable electron and neutral density attachment mass spectrometry method. With the exception of CF2, for which no attachment was observed, all species exclusively underwent dissociative attachment to yield F-. The magnitude and temperature dependences of the rate constants varied significantly between species; however, attachment was in all cases inefficient, never exceeding 2% of the calculated collisional value. The data are interpreted and extrapolated to conditions inaccessible to the experiment using a kinetic modeling approach to the electron attachment process.

Shuman, Nicholas S.; Miller, Thomas M.; Viggiano, A. A.

2012-12-01

8

Synthesis and Chemistry of Strained and Conjugated Fluorocarbons.  

National Technical Information Service (NTIS)

The objective of this project was to synthesize and study the chemistry of an array fluorocarbons and fluorocarbon derivatives in order to further understanding of fluorine as substituent in organic chemistry. Target molecules, all of which incorporated c...

D. M. Lemal

1989-01-01

9

Fluorocarbon Emulsion as a Candidate for Artificial Blood  

Microsoft Academic Search

A method of specifying particle size distribution in fluorocarbon emulsion by means of stepwise centrifugation is proposed. On account of very large specific density of fluorocarbon, a physical calculation was made to classify particle size (the maximum and average) of fluorocarbon emulsion in correlation with centrifugal rotation applying Stokes’ law of sedimentation. Samples of FC emulsion were made with different

T. Fujita; T. Sumaya; K. Yokoyama

1971-01-01

10

Environmental Hazard Assessment of One and Two Carbon Fluorocarbons.  

National Technical Information Service (NTIS)

This report reviews the potential environmental hazard from the commercial use of large quantities of saturated, one and two carbon fluorocarbon compounds which are used for the most part as aerosol propellants, refrigerants, solvents, foaming agents, and...

A. Hanchett P. H. Howard P. R. Durkin

1974-01-01

11

Fluoro-Carbonate Solvents for Li-Ion Cells.  

National Technical Information Service (NTIS)

A number of fluoro-carbonate solvents were evaluated as electrolytes for Li-ion cells. These solvents are fluorine analogs of the conventional electrolyte solvents such as dimethyl carbonate, ethylene carbonate, diethyl carbonate in Li-ion cells. Conducti...

Nagasubramanian

1999-01-01

12

Intermolecular Radical-Solvent Hyperfine Coupling in Fluorocarbons.  

National Technical Information Service (NTIS)

Experimental dynamic nuclear polarization measurements at 74 G for a large number of fluorocarbon solutions containing free radicals led to four empirical conclusions independent of the system chosen for study: (1) protons in C-H bonds exhibit no detectab...

J. A. Potenza E. H. Poindexter

1968-01-01

13

Fluorinated diamond particles bonded in a filled fluorocarbon resin matrix  

DOEpatents

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.

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

1985-01-01

14

Fluorinated diamond particles bonded in a filled fluorocarbon resin matrix  

DOEpatents

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.

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

1983-11-14

15

Silicon dioxide etching yield measurements with inductively coupled fluorocarbon plasmas  

NASA Astrophysics Data System (ADS)

Oxide etching yield has been measured directly with inductively coupled fluorocarbon plasmas. The yields measurement technique of this work can provide useful information for feature profile evolution modeling, which is essential to understand various issues in oxide etching such as reactive ion etching (RIE) lag, inverse RIE lag, etch stop, microtrenching, bowing, etc. Etching and deposition yields per ion were measured using quartz crystal microbalance (QCM) as a function of ion bombardment energy, ion-to-neutral flux ratio, and ion-impinging angle. C2HF5, C2F6, C2H4F2, and C4F8 were used for the oxide etching. Oxide etching mechanism with those gases is complex because etching and deposition are involved at the same time. In highly selective processes fluorocarbon deposition plays important role in determining etching characteristics. Two fluorocarbon deposition mechanisms are identified in this work: neutral deposition and ion-enhanced deposition. The low-energy ions are believed to enhance the deposition rates by creating active sites and fluorocarbon neutrals deposit on the active sites with higher sticking probability. A surface kinetic model is suggested to explain the ion-enhanced mechanism and shows good agreement with experimental data. Angular yield measurement shows that when fluorocarbon deposition is relatively severe, etching yield decreases significantly as the incident angle increases and deposit fluorocarbon at a high incident angle above 60°.

Chae, Heeyeop; Vitale, Steven A.; Sawin, Herbert H.

2003-03-01

16

Molecular Tailoring of Fluorocarbon Ether Bibenzoxazole Polymers to Lower Glass Transition Temperatures.  

National Technical Information Service (NTIS)

The synthesis of fluorocarbon ether bis(o-aminophenol) monomers was accomplished by a multistep route from long-chain fluorocarbon ether diiodides and the reaction conditions optimized. Polycyclocondensation of these monomers with novel, long-chain fluoro...

R. C. Evers

1975-01-01

17

Effect of capacitive coupling on inductively coupled fluorocarbon plasma processing  

SciTech Connect

This article describes results obtained using various plasma and surface diagnostics in a study of inductively coupled fluorocarbon plasmas in which the amount of capacitive coupling was systematically varied. It is found that the plasma density decreases while the electron temperature increases as the amount of capacitive coupling is increased at a constant source power level. The rate at which the dielectric coupling window is eroded is found to scale with both the peak-to-peak rf voltage and the ion current density, and the dielectric window erosion is found to influence the resulting plasma gas-phase chemistry. The changes in plasma electrical and chemical characteristics have a large impact on the surface processes occurring in inductively coupled fluorocarbon plasmas such as fluorocarbon deposition, fluorocarbon etching, SiO{sub 2} etching and Si etching. Further, we show how the selective SiO{sub 2}-to-Si etch process changes with varying capacitive coupling. {copyright} {ital 1999 American Vacuum Society.}

Schaepkens, M.; Rueger, N.R.; Beulens, J.J.; Li, X.; Standaert, T.E.; Matsuo, P.J.; Oehrlein, G.S. [University at Albany, State University of New York, Albany, New York 12222 (United States)

1999-11-01

18

Effect of capacitive coupling on inductively coupled fluorocarbon plasma processing  

Microsoft Academic Search

This article describes results obtained using various plasma and surface diagnostics in a study of inductively coupled fluorocarbon plasmas in which the amount of capacitive coupling was systematically varied. It is found that the plasma density decreases while the electron temperature increases as the amount of capacitive coupling is increased at a constant source power level. The rate at which

M. Schaepkens; N. R. Rueger; J. J. Beulens; X. Li; T. E. F. M. Standaert; P. J. Matsuo; G. S. Oehrlein

1999-01-01

19

Fluoro-Carbonate Solvents for Li-Ion Cells  

SciTech Connect

A number of fluoro-carbonate solvents were evaluated as electrolytes for Li-ion cells. These solvents are fluorine analogs of the conventional electrolyte solvents such as dimethyl carbonate, ethylene carbonate, diethyl carbonate in Li-ion cells. Conductivity of single and mixed fluoro carbonate electrolytes containing 1 M LiPF{sub 6} was measured at different temperatures. These electrolytes did not freeze at -40 C. We are evaluating currently, the irreversible 1st cycle capacity loss in carbon anode in these electrolytes and the capacity loss will be compared to that in the conventional electrolytes. Voltage stability windows of the electrolytes were measured at room temperature and compared with that of the conventional electrolytes. The fluoro-carbon electrolytes appear to be more stable than the conventional electrolytes near Li voltage. Few preliminary electrochemical data of the fluoro-carbonate solvents in full cells are reported in the literature. For example, some of the fluorocarbonate solvents appear to have a wider voltage window than the conventional electrolyte solvents. For example, methyl 2,2,2 trifluoro ethyl carbonate containing 1 M LiPF{sub 6} electrolyte has a decomposition voltage exceeding 6 V vs. Li compared to <5 V for conventional electrolytes. The solvent also appears to be stable in contact with lithium at room temperature.

NAGASUBRAMANIAN,GANESAN

1999-09-17

20

Application of a chemically adsorbed fluorocarbon film to improve demolding  

Microsoft Academic Search

The use of an extremely thin chemically adsorbed fluorocarbon film (having a thickness of the order of 1nm) for injection molding greatly reduces the ejection resistance, depending on the mold shape or dimensional accuracy.Consequently, this technique should be very beneficial when applied to the molding of resin materials that have difficulty with mold release, such as silicone, urethane and elastomer

Hiroyuki Yamamoto; Yuji Ohkubo; Kazufumi Ogawa; Kunihiro Utsumi

2009-01-01

21

Alveolar Surface Tension in Fluorocarbon-Filled Lungs.  

National Technical Information Service (NTIS)

The quasi-static pressure-volume relationship of excised dogs' lungs filled with air and subsequently with FC-80 fluorocarbon liquid and of lungs first filled with air and then with 0.9% BaCl in water was determined by volume displacement plethysmography....

J. A. Kylstra W. H. Schoenfisch

1971-01-01

22

METHOD FOR DETERMINING THE STABILITY OF FLUOROCARBON IOLS  

DOEpatents

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.

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

1959-07-21

23

Plasma chemistry of fluorocarbon RF discharges used for dry etching  

NASA Astrophysics Data System (ADS)

Investigations on capacitively coupled RF plasma in flurocarbon gases excited at 13.56 MHz are reported. These plasmas are commonly used for many applications where a substrate must be etched, for example in the manufacturing of integrated circuits. Diagnostics to measure the densities of both neutral and charged species in RF plasma of fluorocarbon gases that are widely used for etching of Si and SiO2 and to determine the etching characteristics of those discharges in various circumstances were developed. The experimental results are compared with numerical models of the kinetics of both charged and neutral particles in the plasma. The state of the surface was analyzed in situ, to obtain information on etching mechanisms for Si and SiO2 substrates in fluorocarbon plasma. The study focuses on CF4 plasma. Results on other fluorine containing gases are used as a comparison.

Haverlag, Marco

1991-09-01

24

Nanoscale Patterning in Mixed Fluorocarbon-Hydrocarbon Phospholipid Bilayers  

PubMed Central

A growing body of literature suggests that fluorocarbons can direct self-assembly within hydrocarbon environments. We report here the fabrication and characterization of supported lipid bilayers (SLBs) composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and a synthetic, fluorocarbon-functionalized analog, 1. AFM investigation of these model membranes reveals an intricate, composition-dependent domain structure consisting of ~50 nm stripes interspersed between ~1 µm sized domains. Although DSC of 1 showed a phase transition near room temperature, DSC of DPPC:1 mixtures exhibited complex phase behavior suggesting domain segregation. Finally, temperature-dependent AFM of DPPC:1 bilayers shows that, while the stripe structures can be melted above the Tm of 1, the stripes and domains result from immiscibility of the hydrocarbon and fluorocarbon lipid gel phases. Fluorination appears to be a promising strategy for chemical self-assembly in two dimensions. In particular, because no modification is made to the lipid headgroups, it may be useful for nanopatterning biologically relevant ligands on bilayers in vitro or in living cells.

Yoder, Nicholas C.; Kalsani, Venkateshwarlu; Schuy, Steffen; Vogel, Reiner; Janshoff, Andreas; Kumar, Krishna

2008-01-01

25

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

Code of Federal Regulations, 2010 CFR

...Specifications for Fluorocarbon and Other Refrigerants A Appendix A to Subpart F of Part...Specifications for Fluorocarbon and Other Refrigerants This appendix is based on the Air-Conditioning...standard is to evaluate and accept/reject refrigerants regardless of source...

2009-07-01

26

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

Code of Federal Regulations, 2012 CFR

...Specifications for Fluorocarbon and Other Refrigerants A Appendix A to Subpart F of Part...Specifications for Fluorocarbon and Other Refrigerants This appendix is based on the Air-Conditioning...standard is to evaluate and accept/reject refrigerants regardless of source...

2012-07-01

27

Telomeric THAM-derived perfluoroalkylated surfactants for fluorocarbon emulsions.  

PubMed

New fluorophilic and hydrophilic, cost efficient telomeric surfactants derived from tris(hydroxymethyl)acrylaminomethane were synthesized in 2 steps in 80% yield with respect to the perfluoroalkylated telogen. They demonstrate better ability to emulsify fluorocarbons than Pluronic f-68. The biological tolerance of these new surfactants is remarkable, the perfluorohexyl derivative was tolerated at doses of 4g/kg bw after i.v. injection in mice. None of the perfluoroalkylated THAM derivatives induces hemolysis of human red blood cells at concentrations up to 200g/l in physiological solutions. PMID:1391520

Riess, J G; Pavia, A A; Pucci, B; Zarif, L

1992-01-01

28

Fluorocarbon 113 exposure and cardiac dysrhythmias among aerospace workers  

SciTech Connect

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.

Egeland, G.M.; Bloom, T.F.; Schnorr, T.M.; Hornung, R.W.; Suruda, A.J.; Wille, K.K. (National Institute for Occupational Safety and Health, Cincinnati, OH (United States))

1992-01-01

29

Roughness assessment and wetting behavior of fluorocarbon surfaces.  

PubMed

The wetting behavior of fluorocarbon materials has been studied with the aim of assessing the influence of the surface chemical composition and surface roughness on the water advancing and receding contact angles. Diamond like carbon and two fluorocarbon materials with different fluorine content have been prepared by plasma enhanced chemical vapor deposition and characterized by X-ray photoemission, Raman and FT-IR spectroscopies. Very rough surfaces have been obtained by deposition of thin films of these materials on polymer substrates previously subjected to plasma etching to increase their roughness. A direct correlation has been found between roughness and water contact angles while a superhydrophobic behavior (i.e., water contact angles higher than 150° and relatively low adhesion energy) was found for the films with the highest fluorine content deposited on very rough substrates. A critical evaluation of the methods currently used to assess the roughness of these surfaces by atomic force microscopy (AFM) has evidenced that calculated RMS roughness values and actual surface areas are quite dependent on both the scale of observation and image resolution. A critical discussion is carried out about the application of the Wenzel model to account for the wetting behavior of this type of surfaces. PMID:22483335

Terriza, Antonia; Álvarez, Rafael; Borrás, Ana; Cotrino, José; Yubero, Francisco; González-Elipe, Agustín R

2012-03-22

30

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

PubMed Central

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.

OKAGBARE, PAUL I.; MORRIS, MICHAEL D.

2012-01-01

31

Electron Attachment to Fluorocarbon Radicals and Unstable Molecules: CF2 and C2F5  

NASA Astrophysics Data System (ADS)

Electron attachment to unstable fluorocarbon molecules has been investigated; CF2 - no dissociative electron attachment was observed, C2F5 - electron attachment observed at close to zero electron energy with the observation of C2F5-.

Field, T. A.; Graupner, K.; Haughey, S.; Mayhew, C. A.; Shuman, N. S.; Miller, T. M.; Friedman, J. F.; Viggiano, A. A.

2012-11-01

32

Preliminary Environmental Hazard Assessment of Chlorinated Naphthalenes, Silicones, Fluorocarbons, Benzenepolycarboxylates, and Chlorophenols.  

National Technical Information Service (NTIS)

A literature search of pertinent information and data on chlorinated naphthalenes, silicones, fluorocarbons, benzenepolycarboxylates, and chlorophenols was conducted to determine any hazard to man or the environment from commercial use of these chemicals....

P. H. Howard P. R. Durkin

1973-01-01

33

Generation of fluorocarbon and hydrocarbon hybrid gemini surfactants controlled by micellar miscibility.  

PubMed

Hybrid surfactants were generated through the simple mixing of fluorocarbon and hydrocarbon gemini surfactants in aqueous solutions at 25°C. Disulfide exchange between the disulfide in the spacer chain occurred in the mixed micelles. However, the generation of hybrid gemini surfactants was particularly inhibited by the addition of salt. The suppression of the electrostatic repulsion between the hydrophilic headgroups led to the close packing of the hydrophobic chains in the micelles, resulting in the increased immiscibility of the fluorocarbon and hydrocarbon surfactants. On the other hand, when fluorocarbon-fluorocarbon or hydrocarbon-hydrocarbon surfactants were mixed, equilibrium with a 1:2 ratio of symmetric and dissymmetric gemini surfactants was attained after incubation for 24 h. PMID:23357813

Asakawa, Tsuyoshi; Ozawa, Tadahiro; Ohta, Akio

2013-01-01

34

Tunable hydrophilicity on a hydrophobic fluorocarbon polymer coating on silicon  

SciTech Connect

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

Kolari, K.; Hokkanen, A. [VTT Information Technology, Tietotie 3, 02150 Espoo (Finland)

2006-07-15

35

Wettability and thermal stability of fluorocarbon films deposited by deep reactive ion etching  

SciTech Connect

Fluorocarbon films have low surface energy and can be used as antistiction coating for microelectromechanical systems. By using the passivation process in a deep reactive ion etcher, the fluorocarbon films can be deposited and integrated with other processes in the clean room. The properties such as wettability, surface energies, and thermal stability, have been investigated in detail. It has been found that the fluorocarbon films deposited have a static water contact angle of 109 deg. and a surface energy around 14.5 mJ/m{sup 2}, whereas as-received and as-deposited single silicon, poly silicon, and silicon nitride have a much lower water contact angle and a higher surface energy. The fluorocarbon films keep their good hydrophobicity up to 300 deg. C, and the degradation temperature depends on the thickness of the fluorocarbon films. Decomposition happens at lower temperatures (100-300 deg. C) even though the decomposition rate is quite slow without affecting the contact angle. The decomposition mechanism at low temperatures (less than 300 deg. C) might be different from that at high temperatures. It has been shown that the fluorocarbon film deposited by a deep reactive ion etcher tool provides very high hydrophobicity, low surface energy, good thermal stability, and antiadhesion behavior for use in nanoimprinting lithography.

Zhuang Yanxin; Menon, Aric [MIC, Department of Micro and Nanotechnology, Technical University of Denmark, Building 345 east, DK-2800, Kgs. Lyngby (Denmark)

2005-05-01

36

Evidence of direct SiO{sub 2} etching by fluorocarbon molecules under ion bombardment  

SciTech Connect

In a beam apparatus, influence of fluorocarbon gas (C{sub 5}F{sub 8}, C{sub 4}F{sub 8}, and CF{sub 4} molecules) flux onto SiO{sub 2} etching reaction is investigated in comparison to a case of CF{sub 2} radical flux. Fluorocarbon molecules or CF{sub 2} radicals are incident onto SiO{sub 2} surface with Ar{sup +} beam of energy 100-900 eV. Atomic composition of SiO{sub 2} surface under the ion and molecule incidence is measured by in situ x-ray photoelectron spectroscopy. Fluorocarbon/Ar{sup +} co-incidence enhances the SiO{sub 2} etching compared with pure Ar{sup +} incidence, suggesting the etching effect of fluorocarbon molecules under Ar{sup +} bombardment. In the case of C{sub 5}F{sub 8}/Ar{sup +} co-incidence, formation of fluorocarbon layer is observed as the case of CF{sub 2}/Ar{sup +} co-incidence. Etching yields of SiO{sub 2} by C{sub 5}F{sub 8}/Ar{sup +} and CF{sub 2}/Ar{sup +} co-incidences are measured for different Ar{sup +} incident energies and fluorocarbon/Ar{sup +} flux ratios. The etching yield increases monotonically with the Ar{sup +} incident energy, and reaches the value of 2.4 at 900 eV in case of C{sub 5}F{sub 8}, which is about 1.5 times as high as in the CF{sub 2} case. In the case of C{sub 5}F{sub 8} and CF{sub 2}, a phenomenon like etch stop, with formation of a thick fluorocarbon layer, is observed for larger fluorocarbon flux, with the threshold of the fluorocarbon/Ar{sup +} flux, ratio between 2.5 and 25. These results suggest a significant contribution of direct SiO{sub 2} etching by fluorocarbon molecules in practical etching reactors, especially in case of the C{sub 5}F{sub 8} molecule.

Takada, N.; Toyoda, H.; Murakami, I.; Sugai, H. [Department of Electrical Engineering and Computer Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

2005-01-01

37

Frictional properties of mixed fluorocarbon/hydrocarbon silane monolayers: a simulation study.  

PubMed

Because of small surface area to volume ratios nanoscale devices can exhibit dominant surface forces that can quickly degrade unlubricated contacting surfaces. While fluorinated materials have been widely used as lubricants, because of their low critical surface tension and high thermal and mechanical stability, fluorinated monolayer coatings, which are suitable for lubricating nanoscale devices, are less effective as lubricants. Although fluorinated monolayers are more stable than their hydrocarbon counterparts against elevated temperature and humidity, they are known to exhibit higher frictional forces. To overcome this issue, here we study mixed monolayers composed of both hydrocarbon and fluorocarbon chains. Hydrocarbon-based monolayers have been widely studied and shown to improve frictional properties and device life. To investigate the frictional behavior of mixed fluorocarbon/hydrocarbon monolayers, molecular dynamics simulations of pure hydrogenated and fluorinated chains and mixed fluorinated/hydrogenated chains on silica surfaces have been performed. The adhesion and friction between the nanoconfined monolayers as a function of normal load, chain length, and chemical composition of the monolayer coating have been investigated, and mixed fluorocarbon/hydrocarbon monolayers found to outperform both pure fluorocarbon and pure hydrocarbon monolayers. Surface coverage was found to have a significant effect on the performance of all systems studied with higher surface coverage resulting in lower frictional forces. The simulations also show that when the hydrocarbon chains in the monolayer are longer than the fluorocarbon chains, a liquidlike layer is formed by the longer hydrocarbon chains that protrudes above the shorter fluorocarbon chains and aids in friction reduction. A frictional load dependence is also seen in these mixed monolayer systems because of repulsive interactions between the fluorocarbon base layer and the hydrocarbon liquidlike layer. A chain length difference of eight carbons between the base layer and the liquidlike layer was found to provide the lowest friction, while both a larger (because of increased entanglement) and a smaller (insufficient atoms between the contacting base layers to form a liquidlike layer) chain length difference increased friction. PMID:22937771

Lewis, J Ben; Vilt, Steven G; Rivera, Jose L; Jennings, G Kane; McCabe, Clare

2012-09-25

38

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

PubMed Central

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.

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

2010-01-01

39

Temperature dependence of acoustic impedance for specific fluorocarbon liquids.  

PubMed

Recent studies by our group have demonstrated the efficacy of perfluorocarbon liquid nanoparticles for enhancing the reflectivity of tissuelike surfaces to which they are bound. The magnitude of this enhancement depends in large part on the difference in impedances of the perfluorocarbon, the bound substrate, and the propagating medium. The impedance varies directly with temperature because both the speed of sound and the mass density of perfluorocarbon liquids are highly temperature dependent. However, there are relatively little data in the literature pertaining to the temperature dependence of the acoustic impedance of these compounds. In this study, the speed of sound and density of seven different fluorocarbon liquids were measured at specific temperatures between 20 degrees C and 45 degrees C. All of the samples demonstrated negative, linear dependencies on temperature for both speed of sound and density and, consequently, for the acoustic impedance. The slope of sound speed was greatest for perfluorohexane (-278 +/- 1.5 cm/s-degrees C) and lowest for perfluorodichlorooctane (-222 +/- 0.9 cm/s-degrees C). Of the compounds measured, perfluorohexane exhibited the lowest acoustic impedance at all temperatures, and perfluorodecalin the highest at all temperatures. Computations from a simple transmission-line model used to predict reflectivity enhancement from surface-bound nanoparticles are discussed in light of these results. PMID:12509007

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

2002-12-01

40

Brillouin enhanced four-wave mixing with the liquid fluorocarbon  

NASA Astrophysics Data System (ADS)

Stimulated Brillouin Scattering (SBS) is a nonlinear optical effect that is broadly used for correcting the beam quality of laser beams, their mode control, amplification and phase conjugation. Two factors are essential when it comes to selection of the nonlinear medium for SBS, its efficiency or gain coefficient and safety. For example, a low SBS gain coefficient in the fluorocarbon liquid C8F18 is at least one order of magnitude lower than other nonlinear media, typically limits its application in high-power laser systems. However, highly purified C8F18 is a very safe and stable nonlinear medium, and in combination with its high optical breakdown threshold, has become attractive for many practical applications. This paper discusses a phase conjugate mirror (PCM) using the SBS effect in C8F18. A PCM reflectivity of better than 90% has been achieved in an optimized experimental geometry of the incoming beam. The output energy of the phase conjugated pulse linearly increased with the energy of the input pulse beyond a threshold level of about 3.3 mJ. The estimated slope efficiency is about 95%. For weak signal amplification, we have realized greater than 105 amplification with Brillouin enhanced four wave mixing (BEFWM) with an input signal at the level of several nJs. A reflected energy as high as 11 mJ has been achieved with a 400 ?J incoming input signal. Further lowering of the signal energy should result in a higher amplification.

Wu, Frank F.

2012-02-01

41

Characterization of zeolite structure and fluorocarbon reactivity using solid state NMR and x-ray powder diffraction  

Microsoft Academic Search

The research presented in this thesis involves a combination of techniques used to study the structure and interactions zeolites adsorbed with fluorocarbons. This research is specifically aimed at understanding the processes of adsorption, binding, and reactivity of fluorocarbons on cation exchanged faujasite type zeolites. The solid state ion exchange process has also been studied since it is one way to

Michael Frank Ciraolo

2000-01-01

42

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

SciTech Connect

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.

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

2004-09-21

43

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

PubMed

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

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

2009-06-01

44

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

PubMed

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

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

2013-06-10

45

The environmental history and probable future of Fluorocarbon 11  

SciTech Connect

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

Khalil, M.A.K.; Rasmussen, R.A. [Oregon Graduate Institute, Portland, OR (United States)

1993-12-01

46

Biodistribution of mixed fluorocarbon-hydrocarbon dowel molecules used as stabilizers of fluorocarbon emulsions: a quantitative study by fluorine nuclear magnetic resonance (NMR).  

PubMed

19F NMR spectroscopy was used to determine quantitatively the organ distribution and organ retention time in rats of the mixed fluorocarbon-hydrocarbon dowel molecule C6F13CH = CHC10H21 (F6H10E), which stabilizes highly concentrated injectable fluorocarbon emulsions destined for in vivo oxygen transport and delivery. The only fluorine resonances detected in the 19F NMR spectra of the organs analyzed were those of the F6H10E dowel itself, indicating that metabolites, if present, have very low concentrations (< 10(-4) M, limit of our assay). The F6H10E content in the liver peaked 1 day after administration (7 days for the spleen). At a dose of 3.6 g/kg body weight, the half-life of F6H10E in the liver was 25 +/- 5 days. PMID:8140043

Zarif, L; Postel, M; Septe, B; Trevino, L; Riess, J G; Mahé, A M; Follana, R

1994-01-01

47

The interaction of small oxygenated fluorocarbons and hydrocarbons with the Ru(001) surface  

SciTech Connect

The interaction of oxygenated fluorocarbons with Ru(001) is investigated by thermal desorption spectroscopy in an effort to model how technologically important lubricants interact with metal surfaces. The data are compared with those of analogous oxygenated hydrocarbons. In the limit of low exposure, fluorinated molecules bond between 8 and 18 kJ/mol more weakly to Ru(001) than analogous hydrocarbons in cases where the interaction arises from oxygen lone pair electron donation to the surface. Adsorbed oxygenated fluorocarbons are more stable toward decomposition than the hydrogenated compounds. The stability of the fluorocarbons is attributed to the weak adsorption bond, the strength of the C-F bond or the adsorption geometry. The adsorption bonds of oligomeric ethers do not increase in multiples of the monoether-surface bond. For a fluorinated diether, the adsorption bond is approximately equal to that of the monoether. For the hydrogenated ethers, the adsorption bond increases up to 35% on the addition of an ether linkage. This increase is attributed to adsorption primarily through only one oxygen-metal bond or through several weaker-than-expected oxygen-metal bonds. Fundamental research on the interaction of oxygenated fluorocarbons with metal surfaces, such as that described here, can potentially improve the related industrially important lubricants. 129 refs., 35 figs., 7 tabs.

Walczak, M.M.

1990-01-01

48

Catalytic dry powder material for fuel cell electrodes comprising fluorocarbon polymer and precatalyzed carbon  

SciTech Connect

A novel powder particularly suitable for forming the catalyst layer in the manufacture of electrochemical cell electrodes comprises a high molecular weight fluorocarbon polymer and precatalyzed carbon. The maximum size of the particles is about five microns and the polymer has a molecular weight of at least one million. 5 claims.

Singer, R.M.

1979-12-04

49

Release and fate of fluorocarbons in a shredder residue landfill cell: 2. Field investigations.  

PubMed

The shredder residues from automobiles, home appliances and other metal containing products are often disposed in landfills, as recycling technologies for these materials are not common in many countries. Shredder waste contains rigid and soft foams from cushions and insulation panels blown with fluorocarbons. The objective of this study was to determine the gas composition, attenuation, and emission of fluorocarbons in a monofill shredder residue landfill cell by field investigation. Landfill gas generated within the shredder waste primarily consisted of CH(4) (27%) and N(2) (71%), without CO(2), indicating that the gas composition was governed by chemical reactions in combination with anaerobic microbial reactions. The gas generated also contained different fluorocarbons (up to 27 ?g L(-1)). The presence of HCFC-21 and HCFC-31 indicated that anaerobic degradation of CFC-11 occurred in the landfill cell, as neither of these compounds has been produced for industrial applications. This study demonstrates that a landfill cell containing shredder waste has a potential for attenuating CFC-11 released from polyurethane (PUR) insulation foam in the cell via aerobic and anaerobic biodegradation processes. In deeper, anaerobic zones of the cell, reductive dechlorination of CFCs to HCFCs was evident, while in the shallow, oxic zones, there was a high potential for biooxidation of both methane and lesser chlorinated fluorocarbons. These findings correlated well with both laboratory results (presented in a companion paper) and surface emission measurements that, with the exception from a few hot spots, indicated that surface emissions were negative or below detection. PMID:20444588

Scheutz, Charlotte; Fredenslund, Anders M; Nedenskov, Jonas; Kjeldsen, Peter

2010-05-04

50

Effect of Two Fluorocarbon Lubricity Additives Upon the Thermal Stability of an Advanced Hydrocarbon Jet Fuel.  

National Technical Information Service (NTIS)

Two fluorocarbon lubricity additives were tested in the Minex heat exchanger to determine their effect upon the thermal stability of a highly refined jet fuel. The jet fuel without additives and the fuel with a standard metal deactivator additive were tes...

A. E. Zengel

1966-01-01

51

[Ultrastructural studies of fluorocarbon excretion and uptake in the lung (author's transl)].  

PubMed

Certain fluorochemicals are under discussion as synthetic substitutes for erythrocytes because of their high binding capacity for blood gases. The excretion of fluorocarbons occurs predominately in the lungs. As a part of this process of excretion, active cellular transport can be demonstrated by ultrastructural examination. Chronic organ defects, especially lung fibrosis, were not detected. PMID:6108646

Schnoy, N; Pfannkuch, F

1980-01-01

52

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

Microsoft Academic Search

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

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

2008-01-01

53

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

Microsoft Academic Search

In this study, the physical performance (adhesion resistance, heat resistance, abrasion resistance, chemical resistance) extremely thin, highly durable and chemically adsorbed fluorocarbon film with low surface energy on the metal surface (the thickness is about 1 nm order.) was evaluated, and the evaluation results (durability, demolding resistance) on the actual injection molding performance up to 100,000 shots using a test

Hiroyuki Yamamoto; Yuji Ohkubo; Kazufumi Ogawa; Kunihiro Utsumi

2010-01-01

54

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

Microsoft Academic Search

In this study, the use of an extremely thin and chemically adsorbed fluorocarbon film with no influences on the dimension accuracy of the mold geometries on an injection mold (The thickness is about 1 nanometer order.) was experimentally studied as a great releasing agent to reduce the ejection resistance without any influences on the dimensional accuracy of the mold geometries.

Hiroyuki Yamamoto; Yuji Ohkubo; Kazufumi Ogawa; Kunihiro Utsumi

2010-01-01

55

Plasma enhanced CVD of fluorocarbon films by low-pressure dielectric barrier discharge  

Microsoft Academic Search

Low-pressure dielectric barrier discharge (DBD) plasmas have been used to deposit polymerized fluorocarbon (FC) films on silicon substrates. The effects of discharge pressure and frequency of power supply on the film quality have been systematically investigated. The deposited films were characterized by scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, and static contact angle measurements. Experimental results show that

Dongping Liu; Wei Li; Zhiqing Feng; Xiaodong Tan; Baoxiang Chen; Jinhai Niu; Yanhong Liu

2009-01-01

56

Atmospheric Degradation Mechanisms of Hydrogen Containing Chlorofluorocarbons (HCFC) and Fluorocarbons (HFC).  

National Technical Information Service (NTIS)

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), ...

R. Zellner

1990-01-01

57

Aspects of the use of saturated fluorocarbon fluids in high energy physics  

NASA Astrophysics Data System (ADS)

The excellent dielectric properties of saturated fluorocarbons have allowed their use in direct immersion liquid cooling of electronics, including supercomputers and as heat transfer media in vapour phase soldering and burn-in testing of electronics. Their high density, UV transparency, non-flammability, non-toxicity and radiation tolerance have led to their use as liquid and gas radiator media for RICH detectors in numerous particle physics experiments. Systems to circulate and purify saturated fluorocarbon Cherenkov radiator vapours often rely on thermodynamic evaporation-condensation cycles similar to those used in refrigeration. Their use as evaporative refrigerants was pioneered for the ATLAS silicon tracker, and they are now also used as evaporative coolants in ALICE and TOTEM and as liquid coolants in ATLAS and CMS. Ultrasonic techniques for vapour phase analysis of fluorocarbon mixtures—developed for the SLAC SLD barrel CRID radiator during the 1980s as an alternative to UV refractometry are again under development for the ATLAS tracker evaporative cooling system. Examples of fluorocarbon circulation systems, together with purification and analysis techniques for these versatile fluids are mentioned.

Hallewell, G.

2011-05-01

58

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

PubMed

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

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

2012-07-17

59

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

ERIC Educational Resources Information Center

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

Mahaffy, Cheryl

60

Influence of electron beam irradiation on the mechanical properties and crosslinking of fluorocarbon elastomer  

Microsoft Academic Search

The influence of electron beam irradiation on the mechanical and dynamic mechanical properties, gel fraction and crosslink density of terpolymeric fluorocarbon rubber has been investigated in this paper. An attempt has been made to correlate the structure of the irradiated rubber with the properties. With increase in radiation dose, an increase in degree of crosslinking results which leads to increase

Indranil Banik; Anil K. Bhowmick

1999-01-01

61

Synthesis and Characterization of a Polymeric Fluorocarbon-Diamine Reversed Phase Weak Anion Exchange Silica HPLC Column Packing  

Microsoft Academic Search

Polymeric fluorocarbon-diamine silica column packings were synthesized by first reacting a copolymer of chlorotrifluoroethylene and vinylidene fluoride (Kel-F 800) with piperazine and then reacting this product with aminopropyl silica. This mixed mode reversed phase-weak anion exchange HPLC column and a hydrocarbon (C-8) weak anion exchange silica HPLC column were compared for the separation of aromatic organic acids. Although the fluorocarbon

N. D. Danielson; J. Wangsa; S. A. Shamsi

1995-01-01

62

The environmental history and probable future of fluorocarbon-11  

NASA Astrophysics Data System (ADS)

The atmospheric concentration of fluorocarbon 11 (F-11) has increased steadily since it was first put into commercial use in the late 1930s and early 1940s. The observed trends, however, have two periods of dramatic declines. The first occurred around 1974, when trends started falling from their all time high of 13.8 pptv/yr down to around 7.8 pptv/yr (1 pptv = 10-12 parts by volume) in 1982. This decline occurred at first, probably, because of market conditions and later because of the ban in the United States on inessential uses of F-11, particularly in aerosol spray cans. In the meantime, other uses of F-11, such as blowing foams, increased, causing an increasing trend once again until around 1987, when the atmospheric trends reached 11 pptv/yr (measured 1986-1988, inclusive). After this time, however, the trends have fallen dramatically and are now only 4.6 pptv/yr (measured 1990-1992) and even lower in the middle northern latitudes (about 2 pptv/yr). The recent decline of trend is attributed to the effect of the Montreal Protocol and subsequent agreements that are designed to ban worldwide production before the turn of this century. The atmospheric trends reflect estimated emissions, which reached highest values in 1974 (340-355 Gg/yr; 1 Gg = 109g) and again in 1988 (314-380 Gg/yr). The observed concentrations and trends agree extremely well with those calculated from independent estimates of emissions from the various sources. Atmospheric concentrations of F-11 are calculated from a mass balance theory involving seven reservoirs and their interactions. Three of the reservoirs are at the Earth's surface arising from the uses of F-11 (quick-release applications such as open cell foams and aerosols, nonhermetically sealed refrigeration, and rigid polyurethane foams). We estimate that of the 9150 Gg of F-11 that have been produced throughout its history, at present about 1040 Gg are tied up in rigid foams (90 Gg and 24 Gg are tied up in refrigeration and quick-release applications, respectively). There are four environmental reservoirs (deep oceans, the ocean mixed layer, the troposphere, and the stratosphere). F-11 is dynamically exchanged between these reservoirs and is destroyed principally by photolysis in the stratosphere and by soils at the Earth's surface. At present there are about 5360 Gg in the troposphere, 740 Gg in the stratosphere, and small amounts in the oceans (27 Gg and 6 Gg in the mixed layer and deep oceans, respectively). About 81% of the 9 Tg of F-11 produced is still in the surface or environmental reservoirs (1 Tg = 1012g). The future concentrations of F-11 depend on leakage rates from the surface reservoirs and the atmospheric lifetime. It seems that concentrations are not likely to reach the peaks expected earlier and are likely to decline faster than previously thought. The peak concentration is expected to be about 275 pptv and may occur within the next 2 to 3 years. This abstract, the figures, and their captions form a self-contained condensed description of our results.

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

1993-12-01

63

Viscosity of saturated liquid fluorocarbon refrigerants from 273 to 353 K  

NASA Astrophysics Data System (ADS)

Viscosity measurements were carried out on saturated liquid fluorocarbon refrigerants using an improved capillary viscometer for 11 kinds of fluorocarbon refrigerants; CCl3F (R11), CCl2F2 (R12), CHClF2 (R22), CBrF3 (R13B1), CH3CHF2 (R152a), CCl2FCClF2 (R113), CHCl2CF3 (R123), CHClFCClF2 (R123a), CH3CF3 (R143a), CClF2CCl2F2 (R114), and CH2FCF3 (R134a), in the temperature range from 273 to 353 K. An equation is given to represent the viscosity as a function of temperature.

Kumagai, A.; Takahashi, S.

1991-01-01

64

Viscosity of saturated liquid fluorocarbon refrigerants from 273 to 353 K  

Microsoft Academic Search

Viscosity measurements were carried out on saturated liquid fluorocarbon refrigerants using an improved capillary viscometer for 11 kinds of fluorocarbon refrigerants; CCl3F (R11), CCl2F2 (R12), CHClF2 (R22), CBrF3 (R13B1), CH3CHF2 (R152a), CCl2FCClF2 (R113), CHCl2CF3 (R123), CHClFCClF2 (R123a), CH3CF3 (R143a), CClF2CCl2F2 (R114), and CH2FCF3 (R134a), in the temperature range from 273 to 353 K. An equation is given to represent the

A. Kumagai; S. Takahashi

1991-01-01

65

Design, synthesis and evaluation of fluorocarbons and surfactants for in vivo applications. New perfluoroalkylated polyhydroxylated surfactants.  

PubMed

The progress achieved since the advent of Fluosol-DA is summarized in this paper, with special focus on the synthesis and evaluation of more adequate, reliable, industrially feasible fluorocarbons, structure/property relationships--molecular weight being recognized as the pre-eminent determining factor of both the fluorocarbon's excretion rate and the emulsion's stability-, the preparation of significantly more concentrated, more efficacious emulsions, etc. The key to further progress and better mastery of the emulsions' characteristics, especially in relation to increased shelf-life, prolonged i.v. persistence, and versatility, now lies in the development of new surfactants, better adapted to this objective. New families of well defined, monodisperse perfluoroalkylated polyhydroxylated surfactants derived from sugars and related compounds have been synthesized and fully characterized. Preliminary evaluation of their surface-active properties, emulsion stabilizing capacity and biocompatibility are reported. PMID:3052646

Riess, J G; Arlen, C; Greiner, J; Le Blanc, M; Manfredi, A; Pace, S; Varescon, C; Zarif, L

1988-01-01

66

Vesicles and other supramolecular systems from biocompatible synthetic glycolipids with hydrocarbon and/or fluorocarbon chains.  

PubMed

A series of double-tailed hydrocarbon and/or fluorocarbon glycolipids derived from galactose and glucose have been prepared. These compounds were obtained upon opening a lactono- and maltonolactone moiety by the amino group of either a glycine, glycylglycine or lysine residue. The carboxyl terminus of the glycyl and glycylglycine conjugates was further reacted with the appropriate double-tailed amine. In the case of lysine, the lactonamide conjugate was functionalized with a hydrocarbon and/or fluorocarbon fatty amine and acid, respectively. The ability of such glycolipids to disperse in water, the morphology of self-assemblies formed and the stability of the supramolecular structure obtained were shown to depend on the presence or absence and on the nature of the aminoacid spacer. Most of the compounds described were shown by conventional techniques (TEM, Cryo-TEM, LLS, etc.) to produce stable vesicular systems. PMID:7954977

Guedj, C; Pucci, B; Zarif, L; Coulomb, C; Riess, J G; Pavia, A A

1994-08-01

67

Ageing of thin Ag\\/fluorocarbon plasma polymer nanocomposite films exposed to water-based electrolytes  

Microsoft Academic Search

Ag-containing fluorocarbon plasma polymer nanocomposite films were synthesized by combining plasma polymerization of heptadecafluoro-1-decene (HDFD) with electron beam evaporation of silver. The chemical structure and the microstructure of the Ag\\/HDFD plasma polymer nanocomposite films were characterized by means of X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy (HRTEM). The effect of annealing on the microstructure of silver nanoparticles and the

Xuemei Wang; Christoph Somsen; Guido Grundmeier

2008-01-01

68

Thermal chemical vapor deposition of fluorocarbon polymer thin films in a hot filament reactor  

Microsoft Academic Search

Formation of fluorocarbon polymer films with a linear (CF2–CF2)n molecular structure similar to polytetrafluoroethylene, PTFE is described by a hot filament chemical vapor deposition method. Growth process is analyzed by infrared absorption and C(1s), O(1s) and F(1s) core level electron spectroscopy of films deposited at ?5 and +70°C. Absorption doublet at 1220 and 1160cm?1 assigned to C–F2 asymmetric and symmetric

A. C. Rastogi; S. B. Desu

2005-01-01

69

Very high energy SBS phase conjugation and pulse compression in fluorocarbon liquids  

Microsoft Academic Search

An optical phase conjugation and laser pulse compression of laser light via stimulated Brillouin scattering at high energy are investigated. SBS operation at high-energy and high average power in fluorocarbon liquids is clarified. Fundamental nonlinear and SBS optics data on particle-free Fluorinert liquids are presented. High capacity SBS cells filed with particle-free Fluorinert liquids were used to demonstrate a very

Viliam Kmetik; Hidetsugu Yoshida; Hisanori Fujita; Masahiro Nakatsuka; Tatsuhiko Yamanaka

2000-01-01

70

High performance of phase conjugated stimulated Brillouin scattering mirror based on high purity liquid heavy fluorocarbons  

SciTech Connect

Liquid heavy fluorocarbons are introduced as a new medium for a high power stimulated Brillouin scattering applications. A high energy phase conjugation (over 10 J) with the high reflectivity 98{percent} and excellent fidelity from single cell PC SBS mirror filled with Fluorinert FC 75 was measured. The working medium free of microparticle impurity is essential for a high energy operation. Method of purification was developed. {copyright} {ital 1996 American Institute of Physics.}

Yoshida, H.; Kmetik, V.; Fujita, H. [Institute of Laser Engineering, Osaka University, Yamada-oka 2-6, Suita, Osaka 565 (Japan); Yoshida, K. [Osaka Institute of Technology, Omika-5, Asahi-ku, Osaka 535 (Japan); Yamanaka, T.; Nakai, S. [Institute of Laser Engineering, Osaka University, Yamada-oka 2-6, Suita, Osaka 565 (Japan)

1996-05-01

71

Heavy fluorocarbon liquids for a phase-conjugated stimulated Brillouin scattering mirror.  

PubMed

Heavy fluorocarbon liquids were found to be an ideal medium for high-power stimulated Brillouin scattering experiments. Fluorinert FC-75 gives high reflectivity, near 98%, and excellent fidelity in phase conjugation of 14-J, 18-ns optical pulses. The complete removal of microparticle impurities was found to be essential for avoiding laser damage in a high-energy operation. A method of purification based on ultrafiltration has been developed. PMID:18253400

Yoshida, H; Kmetik, V; Fujita, H; Nakatsuka, M; Yamanaka, T; Yoshida, K

1997-06-01

72

Physical performance of the metal surface covered with the highly durable and chemically adsorbed fluorocarbon film  

Microsoft Academic Search

In this study, the physical performance (adhesion resistance, heat resistance, rubbing resistance, chemical resistance) of an extremely thin and the high durable and chemically adsorbed fluorocarbon film with a low surface energy on the metal surface (the thickness is about 1nm order) was evaluated.The demolding resistance in injection-molding can decrease without compromising the mold shape and dimensional accuracy by using

Hiroyuki Yamamoto; Yuji Ohkubo; Kazufumi Ogawa; Kunihiro Utsumi

2010-01-01

73

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

Microsoft Academic Search

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

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

2005-01-01

74

Measurement of Stimulated Brillouin Scattering Characteristics in Heavy Fluorocarbon Liquids and Perfluoropolyether Liquids  

NASA Astrophysics Data System (ADS)

The reflectivity, threshold energy, and Brillouin shift of a stimulated Brillouin scattering (SBS) were measured in new SBS liquid media. The new liquids consist of four heavy fluorocarbon (FC) liquids and six perfluoropolyether (HT) liquids. Among them, FC-77 and HT-70 were found to be good candidates to replace FC-75 which has been known to be a good SBS medium up to now.

Park, Hyunmin; Lim, Changwhan; Yoshida, Hidetsugu; Nakatsuka, Masahiro

2006-06-01

75

Characterization of Polymer Thin Films Prepared with RF Sputtering with Fluorocarbon Polymer Targets  

NASA Astrophysics Data System (ADS)

Polymer thin films were prepared by RF sputtering with argon (Ar) and tetra-fluorocarbon (CF4) gases. Four fluorocarbon polymers, poly(tetra fluoro ethylene) (PTFE), tetra fluoro ethylene-perfluoro alkylvinyl ether copolymer (PFA), fluorinated ethylene propylene copolymer (FEP), poly(vinylidene di fluoride) (PVDF) were used as the sputtering targets. Molecular structures of sputtered fluorocarbon thin films were analyzed with x-rays photoelectron spectroscopy (XPS) and fourier transform infrared spectroscopy (FT-IR). Wettability of these polymer thin films was estimated with contact angles of water droplets. The contact angles increased with increase of the F/C ratio (fluorine for carbon) of the thin film. PTFE target prepared by a spin coat method was also used for the sputtering target, and analyzed the elemental compositions of the target after the sputtering. The F/C ratio of the polymer thin film prepared by the sputtering with CF4 was almost the same value as that of the thin film with Ar. However, the C/F ratio of the target after the CF4 sputtering was much higher than that after the Ar sputtering.

Kezuka, Kazuya; Uemura, Akihiro; Iwamori, Satoru

76

Release and fate of fluorocarbons in a shredder residue landfill cell: 1. Laboratory experiments.  

PubMed

The shredder residues from automobiles, home appliances and other metal-containing products are often disposed in landfills, as recycling technologies for these materials are not common in many countries. Shredder waste contains rigid and soft foams from cushions and insulation panels blown with fluorocarbons. The objective of this study was to use laboratory experiments to estimate fluorocarbon release and attenuation processes in a monofill shredder residue (SR) landfill cell. Waste from the open SR landfill cell at the AV Miljø landfill in Denmark was sampled at three locations. The waste contained 1-3% metal and a relatively low fraction of rigid polyurethane (PUR) foam particles. The PUR waste contained less blowing agent (CFC-11) than predicted from a release model. However, CFC-11 was steadily released in an aerobic bench scale experiment. Anaerobic waste incubation bench tests showed that SRSR produced significant methane (CH(4)), but at rates that were in the low end of the range observed for municipal solid waste. Aerobic and anaerobic batch experiments showed that processes in SRSR potentially can attenuate the fluorocarbons released from the SRSR itself: CFC-11 is degraded under anaerobic conditions with the formation of degradation products, which are being degraded under CH(4) oxidation conditions prevailing in the upper layers of the SR. PMID:20435458

Scheutz, Charlotte; Fredenslund, Anders M; Nedenskov, Jonas; Kjeldsen, Peter

2010-11-01

77

Histamine Release Associated with Intravenous Delivery of a Fluorocarbon-Based Sevoflurane Emulsion in Canines  

PubMed Central

The purpose of this study was to evaluate the effectiveness of a novel fluorocarbon-based sevoflurane emulsion in dogs previously shown to produce short-term rodent anesthesia. On the basis of an unexpected allergic-type clinical reaction, we also tested the hypothesis that this type of formulation causes histamine release and complement activation. Physiological parameters, plasma histamine levels (radioimmunoassay), and complement activation (enzyme immunoassay) were quantified in response to emulsion components, including F13M5 (the emulsion’s fluorocarbon-based polymer) and methoxy poly(ethylene glycol) 5000 (the polymer’s hydrophilic block). Although the emulsion produced general anesthesia in dogs, they also experienced hypotension and clinical signs suggestive of an allergic-like response (i.e., vasodilation, urticaria, and pruritus upon recovery). Emulsions lacking sevoflurane failed to induce anesthesia but did elicit the allergic response. Plasma histamine levels were significantly increased following injection of micellar solutions of F13M5. Direct complement activation by the emulsion or its components was weak or absent. An allergic response leading to histamine release, likely initiated by the F13M5 component via an immunoglobulin pathway, is associated with an intravenous fluorocarbon-based emulsion of sevoflurane. Subsequently, its usefulness in medicine in its present formulation is limited.

JOHNSON, REBECCA A.; SIMMONS, KEN T.; FAST, JONATHAN P.; SCHROEDER, CARRIE A.; PEARCE, ROBERT A.; ALBRECHT, RALPH M.; MECOZZI, SANDRO

2011-01-01

78

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

NASA Astrophysics Data System (ADS)

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.

Qi, Yu-Hong; Zhang, Zhan-Ping; Wang, Li-Li; Du, Xue-Peng

2009-07-01

79

Effects of radio frequency bias frequency and radio frequency bias pulsing on SiO{sub 2} feature etching in inductively coupled fluorocarbon plasmas  

SciTech Connect

The effect of radio frequency (rf) bias frequency on SiO{sub 2} feature etching using inductively coupled fluorocarbon plasmas is investigated. It is found that the rf bias frequency can have an important effect on SiO{sub 2} feature etch rate, microtrenching phenomena, and SiO{sub 2}-to-photoresist etch selectivity. In addition, the effect of rf bias pulsing on inductively coupled fluorocarbon plasma SiO{sub 2} etching has been studied and a model that describes the data well is presented. The model assumes that fluorocarbon deposition occurs while the rf bias is off, fluorocarbon etching occurs during the first part of time that the bias is on, and substrate etching occurs once the fluorocarbon material has been removed from the substrate. (c) 2000 American Vacuum Society.

Schaepkens, M. [Physics Department, University at Albany, Albany, New York 12222 (United States); Oehrlein, G. S. [Physics Department, University at Albany, Albany, New York 12222 (United States); Cook, J. M. [Lam Research Corporation, Fremont, California 94538-6470 (United States)

2000-03-01

80

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

NASA Astrophysics Data System (ADS)

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

Hopkins, Adam Justin

81

Effect of radio frequency bias power on SiO{sub 2} feature etching in inductively coupled fluorocarbon plasmas  

SciTech Connect

We present and discuss results obtained in studies of the mechanisms underlying various feature size dependencies of SiO{sub 2} etching in inductively coupled fluorocarbon plasmas. The variation of the fluorocarbon deposition rate and the SiO{sub 2} etch rate with both feature size and rf bias power has been measured in a variety of constant aspect ratio features for both an etch stop (C{sub 3}F{sub 6}/H{sub 2}) and a nonetch stop (CHF{sub 3}) feedgas chemistry. (c) 2000 American Vacuum Society.

Schaepkens, M. [Physics Department, University at Albany, Albany, New York 12222 (United States); Oehrlein, G. S. [Physics Department, University at Albany, Albany, New York 12222 (United States); Cook, J. M. [Lam Research Corporation, Fremont, California 94538-6470 (United States)

2000-03-01

82

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

NASA Astrophysics Data System (ADS)

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

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

83

Spatially selective formation of hydrocarbon, fluorocarbon, and hydroxyl-terminated monolayers on a microelectrode array.  

PubMed

A protection-deprotection strategy, using gold oxide as a passivating layer, was used to direct the self-assembly of monolayers (SAMs) selectively at individual gold microelectrodes in an array. This approach allowed the formation of hydroxyl-terminated monolayers, without side reactions, in addition to hydrocarbon and fluorocarbon SAMs. Fluorescence microscopy was used to visualize selective dewetting of hydrophobic monolayers by an aqueous dye solution, and spatially resolved X-ray photoelectron spectroscopy was used to demonstrate a lack of cross-contamination on neighboring microelectrodes in the array. PMID:23679352

Cook, Kevin M; Nissley, Daniel A; Ferguson, Gregory S

2013-05-24

84

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

SciTech Connect

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

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

2008-01-01

85

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

SciTech Connect

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.

Hogen-Esch, T.E.

1996-11-01

86

Study of fluorocarbon plasma in 60 and 100 MHz capacitively coupled discharges using mass spectrometry  

SciTech Connect

The signals of positive ions and radicals formed in the fluorocarbon plasma of the capacitively coupled plasma reactor were measured using a quadrupole mass spectrometry and optical emission actinometry. The plasma was produced at 60 and 100 MHz frequencies for the same reactor configuration and gas mixtures. Experiments were performed at 25 mTorr with a SiO{sub 2} wafer on the grounded electrode. Mass spectra of ions were measured in C{sub 4}F{sub 8}/O{sub 2}/Ar and C{sub 4}F{sub 6}/O{sub 2}/Ar gas mixtures at 500-1500 W generator powers. For 60 and 100 MHz discharges production of fluorocarbon ions and radicals is discussed. It was found that the production of heavy species increases with frequency. The high mass signals such as C{sub 3}F{sub 3}{sup +}, C{sub 2}F{sub 4}{sup +}, C{sub 2}F{sub 5}{sup +}, C{sub 3}F{sub 5}{sup +}, C{sub 4}F{sub 7}{sup +} decrease when CHF{sub 3} is added to the gas mixture. However, the signals of CF{sub x}{sup +} (x=1,2,3) do not change significantly. These results are compared to the results of polymer film deposition on the wafer. It was suggested to control the polymerization film formation by adding small amount of CHF{sub 3} to the process mixture.

Ushakov, Andrey; Volynets, Vladimir; Jeong, Sangmin; Sung, Dougyong; Ihm, Yongho; Woo, Jehun; Han, Moonhyeong [Mechatronics and Manufacturing Technology Center, Samsung Electronics Co. Ltd., 416 Maetan-3 dong, Yeongtong-Gu, Suwon, Gyeonggi-Do 443-742 (Korea, Republic of)

2008-09-15

87

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

SciTech Connect

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.

Lee, P.A.; Sylvia, A.L.; Piantadosi, C.A. (Duke Univ. Medical Center, Durham, NC (USA))

1988-04-01

88

Deposition of fluorocarbon films by Pulsed Plasma Thruster on the anode side  

NASA Astrophysics Data System (ADS)

Fluorocarbon thin films were deposited by Pulsed Plasma Thruster at different angles on the anode side of the thruster. Density and velocity of the plasma in the plume of the Pulsed Plasma Thruster were determined using double and triple Langmuir probe apparatus respectively. The deposited films were characterized by X-ray photoelectron spectroscopy (XPS), scanning probe microscope (SPM) and UV-vis spectrometer. Low F/C ratio (0.64-0.86) fluorocarbon films are deposited. The F/C ratio decreases with angle increasing from 0 degree to 30 degree; however it turns to increase with angle increasing from 45 degree to 90 degree. The films deposited at center angles appear rougher compared with that prepared at angles beyond 45 degree. These films basically show having strong absorption properties for wavelength below 600 nm and having enhanced reflective characteristics. Due to the influence of the chemical composition and the surface morphology of the films, the optical properties of these films also show significant angular dependence.

Zhang, Rui; Zhang, Daixian; Zhang, Fan; He, Zhen; Wu, Jianjun

2013-04-01

89

Chemical transfection of cells in picoliter aqueous droplets in fluorocarbon oil.  

PubMed

The manipulation of cells inside water-in-oil droplets is essential for high-throughput screening of cell-based assays using droplet microfluidics. Cell transfection inside droplets is a critical step involved in functional genomics studies that examine in situ functions of genes using the droplet platform. Conventional water-in-hydrocarbon oil droplets are not compatible with chemical transfection due to its damage to cell viability and extraction of organic transfection reagents from the aqueous phase. In this work, we studied chemical transfection of cells encapsulated in picoliter droplets in fluorocarbon oil. The use of fluorocarbon oil permitted high cell viability and little loss of the transfection reagent into the oil phase. We varied the incubation time inside droplets, the DNA concentration, and the droplet size. After optimization, we were able to achieve similar transfection efficiency in droplets to that in the bulk solution. Interestingly, the transfection efficiency increased with smaller droplets, suggesting effects from either the microscale confinement or the surface-to-volume ratio. PMID:21967571

Chen, Fangyuan; Zhan, Yihong; Geng, Tao; Lian, Hongzhen; Xu, Peisheng; Lu, Chang

2011-10-17

90

Synthesis, Thermal Properties and Cytotoxicity Evaluation of Hydrocarbon and Fluorocarbon Alkyl ?-D-xylopyranoside Surfactants  

PubMed Central

Alkyl ?-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 ?-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 ?-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 ?-D-xylopyranosides with a hydrophobic tail ? 8, but occurred at a significantly lower temperature for hexyl ?-D-xylopyranoside. Short and long-chain alkyl ?-D-xylopyranosides displayed no cytotoxicity at concentration below their aqueous solubility limit. Hydrocarbon and fluorocarbon alkyl ?-D-xylopyranosides with intermediate chain length displayed some toxicity at millimolar concentrations due to apoptosis.

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

91

Study on modification process of photoresist by fluorocarbon ions and radicals  

NASA Astrophysics Data System (ADS)

Etching processes for fabricating high-aspect ratio patterns with nano-scale accuracy are desired in such as a contract hole etching for the silicon dioxide that is used as a dielectric passivation layer over MOSFETs. Photoresists (PR) are indispensable for pattern formation by lithography and for masking of pattern-transfer etching processes. However, the ArF PR have poor tolerability against the process plasma and they may often be deformed to cause line edge roughness, striation, and twisting for the etched features. To overcome these problems and realize sophisticated etching process, we had investigated the reaction of ArF PR with mass-separated fluorocarbon ions, i.e. CFx^+ (x=1˜3). In this research, we employed a plasma beam system to ArF PR to expose active species, i.e. ions and radicals, produced in the inductively coupled plasma of fluorocarbon gases. The ion species are accelerated to specific bombardment energy. The plasma beam chamber is connected to analysis chamber of x-ray photoelectron spectroscopy, and the modified surface layer of ArF PR by the plasma beam produced was analyzed with in-situ analysis. From the XPS results, we found the modified layer after CF4 plasma beam exposure was fluorinated more than that of C4F8.

Takeuchi, Takuya; Amasaki, Shinpei; Takeda, Keigo; Ishikawa, Kenji; Kondo, Hiroki; Sekine, Makoto; Hori, Masaru

2011-11-01

92

Fluorocarbons and Sulfur Hexafluoride ( 6 ): a Methodology for National Emission Inventories and Scenarios Applied to The Netherlands  

Microsoft Academic Search

A six-step methodology for estimating use (Steps 1–5) and emissions (Step 6) of fluorocarbons not regulated under the Montreal Protocol and 6 has been described, to improve insight into emissions in the Netherlands. The last step is largely in line with methods applied in the annual AFEAS reports and under discussion within the IPCC, and estimates HFCs, PFCs, FICs and

C. Kroeze; A. J. C. M. Matthijsen

1998-01-01

93

New fabrication technique of fluorocarbon polymer-coated hollow waveguides by liquid-phase coating for medical applications  

Microsoft Academic Search

A new method to fabricate dielectric-coated hollow waveguides has been proposed based on all liquid-phase techniques. Long silver tubes with an extremely smooth inner surface have been fabricated by using a new process of silver mirror reaction and loss reduction of short silver waveguides has been made by liquid flow-coating of a fluorocarbon polymer.

Yuji Kato; Mitsuo Osawa; Mitsunobu Miyagi; Masaru Aizawa; Shin-ichi Abe; Shinji Onodera

1994-01-01

94

Chapter 4: Production of Second or Third-Generation Fluorine-based Refrigerants from (Photo)Dechlorination of Fluorocarbon Wastes  

Microsoft Academic Search

Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are called first-generation fluorocarbons because they contain chlorine atoms. Because they deplete the ozone layer, the production of CFCs has been banned and HCFCs will soon share the same fate. From this trend one can predict that hundreds of thousands of tons of CFCs or HCFCs presently being used will become harmful wastes in the

Hideo Nishiumi; Koichi Sato; Ryo Kato

2006-01-01

95

Behaviors of CFx Radicals in ECR Fluorocarbon Plasmas and Control of SiO2 Etching by Radical Injection  

NASA Astrophysics Data System (ADS)

indent=5mm In SiO_2/Si selective etching processes using fluorocarbon plasmas, the etching selectivity is affected by the surface reactions of CFx radicals. Therefore, it is necessary to obtain information on the behaviors of the CFx radicals in fluorocarbon plasmas and their surface reactions. We developed the in-situ measurement method of radicals in plasma by infrared diode laser absorption spectroscopy (IRLAS) and could be measured the CFx (x=1-3) radicals in the on-off modulated ECR plasmas using CHF_3, CF_4, C_2F6 and C_4F8 for the first time. It was shown from those measurements that the CFx radical densities, the deposition rate of the fluorocarbon film on the substrate and also the SiO_2/Si etching selectivity could be controlled with changing the duty ratio of the on-off modulated ECR CHF3 plasma and that the CF2 radical was an important precursor of the fluorocarbon film formation. Moreover, we have recently developed radical injection techniques into plasma (RIT) to know the important radical for the plasma etching process. The heated HFPO gas was flown into the process chamber and the CF2 radical density of about 1×10^13 cm-3 (at 900 K) was obtained in t he present experiment. In the Ar and H_2/Ar ECR downstream plasmas with CF2 radical injection, the deposition rates of fluorocarbon films formed on Si surfaces and the etching rates of Si and SiO2 were measured. It was shown that the fluorocarbon film was formed from the CF2 radical under the assist of the ion flux, and in the ECR H_2/Ar plasma where the carbon-rich (F/C=0.4) fluorocarbon film was formed, the high SiO_2/Si etching selectivity was obtained. These results will be useful for the developments of ultrafine plasma process technology. In this review, the results on the behaviors of the CFx radicals in the on-off modulated ECR CHF3 plasma and the highly selective etching of SiO_2/Si in the ECR H_2/Ar downstream plasma with CF2 radical injection are described.

Goto, Toshio; Hori, Masaru

1996-10-01

96

Developments of Basic Researches on Fluorocarbon Plasmas for Material Processing 7.CFx Radical Creation and Destruction at Surfaces in Fluorocarbon Plasmas  

NASA Astrophysics Data System (ADS)

This article reviews recent work concerning the surface production and loss mechanisms of CFx radicals and their role in polymer deposition processes occurring in radio-frequency plasmas in fluorocarbon gases used for the selective etching of SiO2 layers in microelectronic device fabrication. In capacitively-coupled plasmas, CFx radicals are often produced predominantly at the powered electrode surface. In fluorine-rich plasmas the instantaneous back-scattering of neutralised, fragmented incident CFx+ ions is the dominant mechanism. Simultaneously, the radicals are destroyed by recombination at the various surfaces of the reactor. This process is most efficient when the fluorine atom concentration is high, and probably leads to the re-creation of volatile CF4. Therefore, the different reactor surfaces can behave either as net sources or sinks for the radicals. When the fluorine concentration is low, another surface production mechanism dominates the production of CF2, and involves a long-lived surface intermediate. This mechanism is linked to the formation of a polymer layer at the surface via heavy neutrals and ions formed in the gas phase by concatenation reactions of CF2 radicals. Finally, the results obtained in higher density (inductively-coupled, electron cyclotron resonance and helicon) sources is compared to the results in capacitively-coupled sources. In this case, similar surface production and loss mechanisms occur, but the relative importance is changed due to the higher degree of fragmentation, the higher ion fluxes and the lower gas pressure.

Booth, Jean-Paul; Cunge, Gilles

97

Study of micelle formation by fluorocarbon surfactant N-(2-hydroxypropyl)perfluorooctane amide in aqueous solution.  

PubMed

Micelles formed by fluorocarbon surfactant N-(2-hydroxypropyl)perfluorooctane amide in aqueous solution were studied through surface tension, dynamic light scatting (DLS), isothermal titration calorimetry (ITC), and dissipative particle dynamic (DPD) simulations. Through surface tension measurements, the effectiveness of surface tension reduction, the maximum surface excess concentration, and the minimum area occupied per surfactant molecule at the air/water interface were investigated. The critical micelle concentration (cmc) at different temperatures and a series of thermodynamic parameters (?G(m)0, ?H(m)0, ?S(m)0, ?G(ads)0, ?H(m)(A) and ?C(p(m))0) of micellization were evaluated. The thermodynamic parameters showed that the micelle formation was entropy-driven. The micelle formation was also confirmed by ITC and DLS. In addition, the DPD simulations were conducted to simulate the whole process of micelle formation to make micelle formation better understood. PMID:23909751

Dai, Caili; Du, Mingyong; Zhao, Mingwei; You, Qing; Guan, Baoshan; Wang, Xin; Liu, Ping

2013-08-20

98

3D feature profile simulation based on realistic surface kinetic modeling of fluorocarbon plasma etch process  

NASA Astrophysics Data System (ADS)

Recently, one of the critical issues in the etching processes is to achieve ultra high deep contact hole without anomalous behaviors such as sidewall bowing and twisting. To address this issue, we have developed a 3D topography simulator using the level set algorithm based on new memory saving technique, which is suitable in the contact hole etching. For this feature profile simulation, we performed a fluorocarbon plasma-surface kinetic modeling based on our experimental data, a polymer layer based this model was proposed as considering material balance of deposition and etching through steady-state FC layer. Finally, the modeling results showed good agreements with experimental data and could be used successfully for 3D etch profile simulations with consideration of polymer layer.

Chang, Won-Seok; Kwon, Deuk-Chul; Yu, Dong-Hun; Cho, Deog-Gyun; Yook, Yeong-Geun; Kim, Jin-Tae; Yoon, Jung-Sik; Im, Yeon-Ho

2011-11-01

99

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

SciTech Connect

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

Ewing, J.R.; Branch, C.A.; Fagan, S.C.; Helpern, J.A.; Simkins, R.T.; Butt, S.M.; Welch, K.M. (Henry Ford Hospital, Detroit, MI (USA))

1990-01-01

100

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

SciTech Connect

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.

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

2010-01-01

101

Study of the adhesion of thin plasma fluorocarbon coatings resisting plastic deformation for stent applications  

NASA Astrophysics Data System (ADS)

Metallic intravascular stents are medical devices (316L stainless steel) used to support the narrowed lumen of atherosclerotic stenosed arteries. Despite the success of bare metal stents, restenosis remains the main complication after 3-6 months of implantation. To reduce the restenosis rate of bare metal stents, stent coating is an interesting alternative. Firstly, it allows the modification of the surface properties, which is in contact with the biological environment. Secondly, the coating could eventually act as a carrier for drug immobilization and release. Moreover, the in vivo stent implantation requires in situ stent expansion. This mandatory step generates local plastic deformation of up to 25% and may cause coating failures such as cracking and delamination. Fluorocarbon films were selected in this study as a potential stent coating, mainly due to their chemical inertness, high hydrophobicity, protein retention capabilities and thromboresistance properties. The aim of this study was to investigate the adhesion properties of fluorocarbon films of three different thicknesses deposited by plasma polymerization in C2F6/H2 on 316L stainless steel substrates. A previously developed small punch test was used to deform the coated samples. According to atomic force microscopy, field emission scanning electron microscopy and x-ray photoelectron spectroscopy characterizations, among the coatings with different thicknesses studied, only those with a thickness of 36 nm exhibited the required cohesion and interfacial adhesion to resist the stent expansion without cracking or delaminating. Otherwise, cracks were detected in the coatings having thicknesses equal or superior to 100 nm, indicating a lack of cohesion.

Lewis, F.; Horny, P.; Hale, P.; Turgeon, S.; Tatoulian, M.; Mantovani, D.

2008-02-01

102

Perfluoroalkylated telomers derived from tris(hydroxymethyl)acrylamidomethane as surfactants and co-surfactants in fluorocarbon emulsions  

Microsoft Academic Search

The ability of perfluoroalkylated telomers derived from tris(hydroxymethyl)acrylamidomethane (TAC) to stabilize fluorocarbon emulsions has been investigated. For this purpose, 50% w\\/v emulsions of perfluorodecalin (FDC) and perfluoro-octyl bromide (PFOB) were prepared with a total 3% w\\/v of surfactant and were compared with emulsions prepared with Pluronic F-68® or egg yolk phospholipids (EYP). When used as the sole surfactant, telomers 1

Evelyne Myrtil; Leila Zarif; Jacques Greiner; Jean G. Riess; Bernard Pucci; André A. Pavia

1995-01-01

103

Identifying Hydrocarbon and Fluorocarbon Surfactants in Specialty Chemical Formulations of Environmental Interest by Fast Atom Bombardment\\/Mass Spectrometry  

Microsoft Academic Search

Hydrocarbon- and fluorocarbon-based surfactants are used in specialty or 'niche' chemical formulations that are designed for applications such as aircraft deicing and anti-icing, 'spreaders' that increase the effectiveness of pesticide formulations, and for fighting hydrocarbon-fuel fires. The identity of the surfactants in specialty formulations is usually proprietary information. However, this information is needed to design studies that monitor the occurrence

Jennifer A. Fiel; Melissa Schultz; Douglas Barofsky

2003-01-01

104

Evaluation of different fluorocarbon oils for their internal oxygen supply in glucose microsensors operated under oxygen-deficit conditions  

Microsoft Academic Search

Several fluorocarbon oils have been assessed and compared as an internal source of oxygen in connection to their use as binders for carbon-paste glucose biosensors. All four polychlorotrifluoroethylene oils tested dramatically increase the oxygen capacity of carbon-paste enzyme electrodes to allow convenient biosensing under severe oxygen-deficit conditions. The ability to address the oxygen demand depends upon the length of the

Joseph Wang; Liang Chen; Madhu-Prakash Chatrathi

2000-01-01

105

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

PubMed Central

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

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

2013-01-01

106

Biodistribution and excretion of a mixed fluorocarbon-hydrocarbon "dowel" emulsion as determined by 19F NMR.  

PubMed

To investigate the biodistribution, possible metabolism and excretion of mixed fluorocarbon-hydrocarbon "dowel" molecules used as stabilizers of fluorocarbon emulsions, we have prepared a 25% w/v emulsion of such a molecule, and quantitatively evaluated, by means of 19F NMR, its behavior in the blood and reticuloendothelial system (RES) of rats. C6F13CH = CHC10H21 (F6H10E) was emulsified using egg yolk phospholipids (EYP). The emulsion (F6H10E/EYP: 25/6% w/v) was injected intravenously into 33 Sprague Dawley female rats at a 3.6 g/kg body weight dose of F6H10E. The animals were sacrificed at regular intervals of time. 24 hours after the injection, 70% of the injected dose was located in the liver, 17% in the spleen, 4% in the lungs, 2% in the kidneys and 2% in the blood. The half-time retention of the dowel molecule in the liver was estimated to be 25 +/- 5 days. None of the 33 treated animals died prior to the planned sacrifice date. The dowel molecule F6H10E proved to be well tolerated, and excreted reasonably fast, without metabolism. This appears to warrant the use of such molecules as stabilizers in injectable fluorocarbon emulsions destined to serve as oxygen carriers, contrast agents or drug delivery systems. PMID:7849922

Zarif, L; Postel, M; Trevino, L; Riess, J G; Valla, A; Follana, R

1994-01-01

107

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

PubMed

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

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

2013-10-01

108

Thermal behavior and high- and low-temperature phase structures of gemini fluorocarbon/hydrocarbon diblocks.  

PubMed

The thermal behavior and phase structure of two series of gemini fluorocarbon/hydrocarbon diblock amphiphiles with the general formula (CnF2n+1CH2)(Cm - 2H2m - 3)CH-CH(CnF2n+1CH2)(Cm - 2H2m - 3), with n = 8, 10 and m = 6, 12, 14, 16, 18, 20 (abbreviated as di(FnHm)), have been investigated by differential scanning calorimetry, polarized optical and freeze-fracture transmission electron microscopies, dilatometry, and small-angle X-ray scattering (SAXS). The various terms of the series exhibit the same thermal behavior, essentially composed of two exothermal transitions, a low-temperature event that corresponds to the melting of the hydrocarbon chains at TH and a high-temperature transition associated with the melting of the fluorocarbon chains at TF. Below TH, a disordered plastic rotator phase, MLT, and above TH, a lamellar phase, MHT, were determined by SAXS experiments. Above TF, the compounds eventually clear into the isotropic liquid. In the MHT phase, both the Fn and Hm blocks are segregated from each other, forming sublayers with sharp interfaces, as revealed by the five lamellar orders and remarkable sharpness of the SAXS peaks. In the MLT phase, the partial crystallization of the aliphatic blocks when the temperature is lowered leads to the disruption of the aliphatic sublayers into rows of ribbons arranged according to pseudohexagonal and/or rectangular arrangements with different lattice sizes (p2gg symmetry). The Fn segments form the fluorinated continuum. In support of SAXS, molecular packing models of the tetrablocks are proposed on the basis of the temperature/volume variations of di(F10H20) and di(F10H16) in both high- and low-temperature phases, as determined by dilatometry. It is notable that the arrangements found for di(FnHm) are completely different from those previously reported for FnHm diblocks, revealing the influence of the linker unit on the solid-state behavior of the tetrablocks. PMID:23600621

de Gracia Lux, Caroline; Donnio, Bertrand; Heinrich, Benoit; Krafft, Marie Pierre

2013-04-19

109

Oxygenated fluorocarbons adsorbed at metal surfaces: chemisorption bond strengths and decomposition  

SciTech Connect

The authors report studies of the adsorption bond strengths and decomposition of perfluorodiethyl ether and hexafluoroacetone on clean and oxygen-dosed Ru(001). Perfluorodiethyl ether bonds weakly to Ru(001) (39 kJ/mol) without decomposing. This binding energy is typical for a metal-adsorbate interaction in which the adsorbate donates electrons to the metal from the oxygen lone pair. Hexafluoroacetone bonds to the surface in both a weakly bonded configuration (38 kJ/mol) and a strongly bonded configuration (66-87 kJ/mol), and there is some decomposition. They compare the chemistry of these oxygenated fluorocarbons to analogous oxygenated hydrocarbons. They propose that the net effect of fluorination is to weaken those chemisorption bonds which rely upon electron donation from the oxygen lone pairs to the metal but to strengthen the chemisorption bonds which rely primarily upon electron donation from the metal into antibonding C-O orbitals. Both phenomena can be explained by electronic effects resulting from fluorination.

Walczak, M.M.; Leavitt, P.K.; Thiel, P.A.

1987-09-16

110

Ultralow-k silicon containing fluorocarbon films prepared by plasma-enhanced chemical vapor deposition  

NASA Astrophysics Data System (ADS)

Low dielectric constant materials as interlayer dielectrics (ILDs) offer a way to reduce the RC time delay in high-performance ultra-large-scale integration (ULSI) circuits. Fluorocarbon films containing silicon have been developed for interlayer applications below 50-nm linewidth technology. The preparation of the films was carried out by plasma-enhanced chemical vapor deposition (PECVD) using gas precursors of tetrafluorocarbon as the source of active species and disilane (5 vol.% in helium) as a reducing agent to control the ratio of F/C in the films. The basic properties of the low dielectric constant (low-k) interlayer dielectric films are studied as a function of the fabrication process parameters. The electrical, mechanical, chemical, and thermal properties were evaluated including dielectric constant, surface planarity, hardness, residual stress, chemical bond structure, and shrinkage upon heat treatments. The deposition process conditions were optimized for film thermal stability while maintaining a relative dielectric value as low as 2.0. The average breakdown field strength was 4.74 MV/cm. The optical energy gap was in the range 2.2 2.4 eV. The hardness and residual stress in the optimized processed SiCF films were, respectively, measured to be in the range 1.4 1.78 GPa and in the range 11.6 23.2 MPa of compressive stress.

Jin, Yoonyoung; Ajmera, P. K.; Lee, G. S.; Singh, Varshni

2005-09-01

111

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

NASA Astrophysics Data System (ADS)

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

Legeais, Jean-Marc; Renard, Gilles; Parel, Jean-Marie; Savoldelli, Michelle; Pouliquen, Yves

1994-06-01

112

Fluorine-doped SiO 2 and fluorocarbon low- k dielectrics investigated by SIMS  

NASA Astrophysics Data System (ADS)

In this work, we present secondary ion mass spectrometry (SIMS) investigations of the incorporation of fluorine into thin SiO 2 films adapted as low- k dielectrics in the metal-oxide-semiconductor (MOS) devices. The insulating SiOF oxides with the thickness ranging from 1 up to 15 nm have been prepared by plasma-enhanced chemical vapor deposition (PECVD) and/or by reactive ion etching (RIE) methods on <1 0 0> oriented p-Si substrates with the use of either CF 4 or CHF 3 source of the plasma. SIMS experiments were performed using ultra-low energy (1 keV) argon ion beam and quadrupole mass analyzer. Depth profiles of the resulting dielectric films illustrate: (i) the incorporation of F into the SiO 2 matrix is accomplished by either the CHF 3 or CF 4 plasmas; (ii) no etching of SiO 2 matrix is observed by using of CHF 3; (iii) CHF 3 is a source of fluorocarbon film deposition on top of the SiO 2 that prevents the SiO 2 etching; and (iv) fluorine quantifications done based on implantation criteria give the maximum concentrations within the films from 6.0 × 10 18 to 2.4 × 10 20 atoms/cm 3 depending on the different fluoridation conditions. The F concentration in SiO 2 increases with the r.f. power of CF 4 or with decreasing a gas pressure of CHF 3 plasma.

Cwil, M.; Kalisz, M.; Konarski, P.

2008-12-01

113

Vascular perfusion of the isolated rat stomach with a fluorocarbon emulsion.  

PubMed Central

A constant-pressure system using a fluorocarbon (FC-75) containing artificial medium was used for vascular perfusion of the isolated rat stomach. A 10% emulsion of FC-75 in a modified Tyrode solution, containing 3.5% bovine serum albumin, amino acids, nucleosides, and beta-hydroxybutyrate appeared to allow an adequate perfusion for at least seven hours. The following criteria were used to estimate for functional state of the perfused stomach: (1) venous flow, (2) oxygen consumption, (3) leakage from the blood vessels to the gastric lumen, (4) ultrastructure, (5) secretion of H+ and pepsinogen after stimulation, and (6) transport of labelled macromolecules. During perfusion oxygen consumption and venous flow remained, after an initial high value, constant for at least seven hours. Leakage from the vascular bed was absent. Ultrastructure was preserved for at least seven hours. Administration of pilocarpine led to secretion of HCl ad pepsinogen. Pentagastrin and histamine stimulated HCl secretion in only some of the preparations. [3H]-galactose was incorporated into macromolecules and transported from the Golgi-region towards the apex of the cell. These observations led to the conclusion that the described vascular perfusion system in at least an appropriate model for studying glycoprotein synthesis.

Van Huis, G A; Kramer, M F

1981-01-01

114

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

SciTech Connect

The present work focuses on the plasma deposition of fluorocarbon (FC) films on surfaces and the electrostatic control of their wettability (electrowetting). Such films can be employed for actuation of fluid transport in microfluidic devices, when deposited over patterned electrodes. Here, the deposition was performed using C{sub 4}F{sub 8} and the plasma parameters that permit the creation of films with optimized properties desirable for electrowetting were established. The wettability of the plasma-deposited surfaces was characterized by means of contact angle measurements (in the static and dynamic mode). The thickness of the deposited films was probed in situ by means of spectroscopic ellipsometry, while the surface roughness was provided by atomic force microscopy. These plasma-deposited FC films in combination with silicon nitride, a material of high dielectric constant, were used to create a dielectric structure that requires reduced voltages for successful electrowetting. Electrowetting experiments using protein solutions were conducted on such optimized dielectric structures and were compared with similar structures bearing commercial spin-coated Teflon registered amorphous fluoropolymer (AF) film as the hydrophobic top layer. Our results show that plasma-deposited FC films have desirable electrowetting behavior and minimal protein adsorption, a requirement for successful transport of biological solutions in 'digital' microfluidics.

Bayiati, P.; Tserepi, A.; Petrou, P. S.; Kakabakos, S. E.; Misiakos, K.; Gogolides, E. [Institute of Microelectronics-NCSR 'Demokritos', POB 60228, 153 10 Aghia Paraskevi, Attiki (Greece); Institute of Radioisotopes and Radiodiagnostic Products-NCSR 'Demokritos', POB 60228, 153 10 Aghia Paraskevi, Attiki (Greece); Institute of Microelectronics-NCSR 'Demokritos', POB 60228, 153 10 Aghia Paraskevi, Attiki (Greece)

2007-05-15

115

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

SciTech Connect

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.

NIGREY,PAUL J.; BOLTON,DENNIS L.

2000-02-01

116

Influence of electron beam irradiation on the mechanical properties and crosslinking of fluorocarbon elastomer  

NASA Astrophysics Data System (ADS)

The influence of electron beam irradiation on the mechanical and dynamic mechanical properties, gel fraction and crosslink density of terpolymeric fluorocarbon rubber has been investigated in this paper. An attempt has been made to correlate the structure of the irradiated rubber with the properties. With increase in radiation dose, an increase in degree of crosslinking results which leads to increase in modulus and Tg with a corresponding decrease in elongation at break, set and tan ?. The effect of multifunctional monomer is realized only at relatively higher level of trimethylolpropane triacrylate (TMPTA), where improvement in strength and failure properties is observed. The dynamic storage modulus at 50 degC is higher and loss tangent becomes lower. Among the various polyfunctional monomers tripropyleneglycol diacrylate (TPGDA), trimethylolpropane triacrylate (TMPTA) and tetramethylolmethane tetracrylate (TMMT), the mechanical properties and the degree of crosslinking are lowest for systems based on TPGDA. MgO used in the formulation leads to the improvement in mechanical properties. Increase in the crosslink density is in line with reduced loss tangent and increased storage modulus for the MgO filled rubber vulcanizate.

Banik, I.; Bhowmick, A. K.

1999-01-01

117

Characterization of porosity and dielectric constant of fluorocarbon porous films synthesized by using plasma-enhanced chemical vapor deposition and solvent process  

NASA Astrophysics Data System (ADS)

Fluorocarbon films obtained in plasma-enhanced chemical vapor deposition with a C4F8 compound were composed of a carbon cross-linked network and unlinked species encapsulated in the network [J. Appl. Phys. 89, 893 (2001)]. The unlinked species were effectively removed from the films. Then, the network probably containing the pore of the species was extracted on wafers when the films were dipped into tetrahydrofran (THF) solvent. The fact implied that fluorocarbon porous films with a low-dielectric constant might be formed by using dry and wet processes. In the present study, x-ray analyses showed that the THF-treated films actually became porous in the dipping process. The dielectric constant of the THF-treated films was consistently low (<1.9) and reduced by 10% from that of as-deposited films. The fluorocarbon network as a porous medium may be applied to interlayer dielectrics for ultralarge-scale integrated circuits.

Takahashi, Kazuo; Mitamura, Takashi; Ono, Kouichi; Setsuhara, Yuichi; Itoh, Atsushi; Tachibana, Kunihide

2003-04-01

118

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

PubMed

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

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

2012-01-17

119

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

SciTech Connect

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.

Nelson, Caleb T.; Overzet, Lawrence J.; Goeckner, Matthew J. [Department of Electrical Engineering, University of Texas at Dallas, P.O. Box 830688, Richardson, Texas 75083 (United States)

2012-09-15

120

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

SciTech Connect

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.

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

121

Viscoelastic wormlike micelles in mixed nonionic fluorocarbon surfactants and structural transition induced by oils.  

PubMed

Formation and rheological behavior of viscoelastic wormlike micelles in an aqueous solution of a mixed system of nonionic fluorocarbon surfactants, perfluoroalkyl sulfonamide ethoxylate, C8F17SO2N(C3H7)(CH2CH2O)nH (abbreviated as C8F17EOn, n=20 and 3), was studied. A partial ternary phase diagram of water/C8F17EO20/C8F17EO3 was constructed at 25 degrees C by visual inspection through crossed polarizers. In the water/surfactant binary system, C8F17EO20 forms an isotropic micellar solution over a wide concentration range (approximately 80 wt %). The micellar solution of the C8F17EO20 can solubilize a significant amount of C8F17EO3, and the solubility increases with increasing C8F17EO20 concentration. With successive addition of C8F17EO3 to the aqueous C8F17EO20 solution, viscosity increases rapidly, and a viscoelastic solution is formed. The viscosity of the viscous sample was approximately 5th order of magnitude of pure water. The viscoelastic solution follows the Maxwell model typical of wormlike micelles at low-frequency region. With further addition of C8F17EO3 the viscosity decreases, and phase separation occurs. Addition of perfluoropolyether oil, (C3F6O)nCOOH, to the viscoelastic solution decreases the viscosity monotonically until phase separation. On the other hand, when perfluorodecalin oil, C10F18, is added, viscosity first decreases and attains a limiting value before excess oil phase separates out. The viscosity decrease in water/surfactant/oil systems is possibly caused by the microstructural transition in the network structure. Small-angle X-ray scattering (SAXS) measurements were performed to complement the rheological data. It has been found that the C8F17EO3 induces one-dimensional growth to the C8F17EO20 micelles. On the other hand, when (C3F6O)nCOOH is added, wormlike-sphere type transition is more likely to occur. PMID:19193166

Sharma, Suraj Chandra; Shrestha, Rekha Goswami; Shrestha, Lok Kumar; Aramaki, Kenji

2009-02-12

122

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

PubMed

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(?) two-phase region, and a single L(?) 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(?) 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(?) 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 (19)F NMR as well as (31)P NMR measurements. Upon replacement of NFDA by DEHPA, the signal from the (19)F atoms adjacent to the hydrophilic headgroup disappears and that from the (19)F atoms on the main chain becomes sharper. This could be interpreted as an increase of microfluidity in the mixed vesicle bilayers at higher content of DEHPA, whose alkyl chains are expected to have a lower chain melting point. Our results provide basic knowledge on vesicle formation and their structural evolution in salt-free catanionic surfactant systems containing mixed ion pairs, which may contribute to a deeper understanding of the rules governing the formation and properties of surfactant self-assembly. PMID:22646993

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

2012-06-11

123

The water-hydrophobic interface: neutral and charged solute adsorption at fluorocarbon and hydrocarbon self-assembled monolayers (SAMs).  

PubMed

Adsorption of small molecular solutes in an aqueous solution to a soft hydrophobic surface is a topic relevant to many fields. In biological and industrial systems, the interfacial environment is often complex, containing an array of salts and organic compounds in the solution phase. Additionally, the surface itself can have a complex structure that can interact in unpredictable ways with small solutes in its vicinity. In this work, we studied model adsorption processes on hydrocarbon and fluorocarbon self-assembled monolayers by using vibrational sum frequency spectroscopy, with methanol and butylammonium chloride as adsorbates. The results indicate that differences in surface functionality have a significant impact on the organization of adsorbed organic species at hydrophobic surfaces. PMID:23452489

Hopkins, Adam J; Richmond, Geraldine L

2013-03-01

124

Reverse water-in-fluorocarbon emulsions for use in pressurized metered-dose inhalers containing hydrofluoroalkane propellants.  

PubMed

Pulmonary administration of drugs has demonstrated numerous advantages in the treatment of pulmonary diseases due to direct targeting to the respiratory tract. It enables avoiding the first pass effect, reduces the amount of drugs administered, targets drugs to specific sites and reduces their side effects. Reverse water-in-fluorocarbon (FC) emulsions are potential drug delivery systems for pulmonary administration using pressurized metered-dose inhalers (pMDI). The external phase of these emulsions consists of perfluorooctyl bromide (PFOB, perflubron), whereas their internal phase contains the drugs solubilized or dispersed in water. These emulsions are stabilized by a perfluoroalkylated dimorpholinophosphate (F8H11DMP), i.e. a fluorinated surfactant. This study demonstrates the possibility of delivering a reverse fluorocarbon emulsion via the pulmonary route using a CFC-free pMDI. Two hydrofluoroalkanes (HFAs) (Solkane(R) 134a and Solkane(R) 227) were used as propellants, and various solution (or emulsion)/propellant ratios (1/3, 1/2, 2/3, 1/1, 3/2, 3/1 v/v) were investigated. The insolubility of water (with or without the fluorinated surfactant F8H11DMP) in both HFA 227 and HFA 134a was demonstrated. PFOB and the reverse emulsion were totally soluble or dispersible in all proportions in both propellants. This study demonstrated also that the reverse FC emulsion can be successfully used to deliver caffeine in a homogeneous and reproducible way. The mean diameter of the emulsion water droplets in the pressured canister was investigated immediately after packaging and after 1 week of storage at room temperature. Best results were obtained with emulsion/propellant ratios comprised between 2/3 and 3/2, and with HFA 227 as propellant. PMID:11996829

Butz, N; Porté, C; Courrier, H; Krafft, M P; Vandamme, Th F

2002-05-15

125

Study of the SiO{sub 2}-to-Si{sub 3}N{sub 4} etch selectivity mechanism in inductively coupled fluorocarbon plasmas and a comparison with the SiO{sub 2}-to-Si mechanism  

SciTech Connect

The mechanisms underlying selective etching of a SiO{sub 2} layer over a Si or Si{sub 3}N{sub 4} underlayer, a process of vital importance to modern integrated circuit fabrication technology, has been studied. Selective etching of SiO{sub 2}-to-Si{sub 3}N{sub 4} in various inductively coupled fluorocarbon plasmas (CHF{sub 3}, C{sub 2}F{sub 6}/C{sub 3}F{sub 6}, and C{sub 3}F{sub 6}/H{sub 2}) was performed, and the results compared to selective SiO{sub 2}-to-Si etching. A fluorocarbon film is present on the surfaces of all investigated substrate materials during steady state etching conditions. A general trend is that the substrate etch rate is inversely proportional to the thickness of this fluorocarbon film. Oxide substrates are covered with a thin fluorocarbon film ({lt}1.5 nm) during steady-state etching and at sufficiently high self-bias voltages, the oxide etch rates are found to be roughly independent of the feedgas chemistry. The fluorocarbon film thicknesses on silicon, on the other hand, are strongly dependent on the feedgas chemistry and range from {approximately}2 to {approximately}7 nm in the investigated process regime. The fluorocarbon film thickness on nitride is found to be intermediate between the oxide and silicon cases. The fluorocarbon film thicknesses on nitride range from {approximately}1 to {approximately}4 nm and the etch rates appear to be dependent on the feedgas chemistry only for specific conditions. The differences in etching behavior of SiO{sub 2}, Si{sub 3}N{sub 4}, and Si are suggested to be related to a substrate-specific ability to consume carbon during etching reactions. Carbon consumption affects the balance between fluorocarbon deposition and fluorocarbon etching, which controls the fluorocarbon steady-state thickness and ultimately the substrate etching. {copyright} {ital 1999 American Vacuum Society.}

Schaepkens, M.; Standaert, T.E.; Rueger, N.R.; Sebel, P.G.; Oehrlein, G.S. [Department of Physics, University at Albany, State University of New York, Albany, New York, 12222 (United States); Cook, J.M. [Lam Research Corporation, Fremont, California, 94538-6470 (United States)

1999-01-01

126

Measurement of Fluorocarbon Radicals Generated from C4F8\\/H2 Inductively Coupled Plasma: Study on SiO2 Selective Etching Kinetics  

Microsoft Academic Search

The kinetics of highly selective SiO2 etching were studied on the basis of appearance mass spectroscopy (AMS) measurement of fluorocarbon radicals generated from C4F8\\/H2 inductlvely coupled plasma (ICP). Results obtained by varying of H2 concentration in C4F8, total pressure and RF power implied that CF1 radical played a major role in the polymer film deposition. In particular, radical measurements carried

Kazuhiro Kubota; Hiroyuki Matsumoto; Haruo Shindo; Shoso Shingubara; Yasuhiro Horiike

1995-01-01

127

Reliable Stimulated Brillouin Scattering Compression of Nd:YAG Laser Pulses with Liquid Fluorocarbon for Long-Time Operation at 10 Hz  

Microsoft Academic Search

Stokes pulses of high energy and high-average power were obtained by stimulated Brillouin scattering (SBS) compression of long Nd:YAG laser pulses. The SBS medium used in the single-cell compressor was liquid ultrafiltered Fluorinert FC-75 fluorocarbon. An output pulse duration of 0.9 ns and a peak-power enhancement by 1 order of magnitude were observed for 10-ns, 0.57-J input pulses at a

Viliam Kmetik; Henryk Fiedorowicz; Alexander A. Andreev; Klaus J. Witte; Hiroyuki Daido; Hisanori Fujita; Masahiro Nakatsuka; Tatsuhiko Yamanaka

1998-01-01

128

Fundamental Adsorption Properties for Low Molecular Weight Alcohols in Fluorocarbon Thin Films Deposited onto Quartz Crystal Microbalance Electrode by an R.F. Sputtering and Spin Coating  

NASA Astrophysics Data System (ADS)

Highly sensitive detection methods for volatile organic compounds (VOCs) are needed in working environment handling the VOCs. The use of a quartz crystal microbalance (QCM) is one such method, and many studies have been carried out on the deposition of metallic, inorganic and organic thin films onto QCM surfaces for use as sensors. In this paper, we report on adsorption properties of fluorocarbon thin films deposited onto the QCM electrode by an r.f. sputtering and spin coating for low molecular weight VOCs such as aliphatic alcohols and acetone. Adsorption mass of these VOC molecules in the fluorocarbon thin film deposited by the r.f. sputtering were much higher than that in the thin film deposited by the spin coating. It is known that molecular structures of fluorocarbon thin films sputtered with a Poly(tetrafluoroethylene) (PTFE) target were quite different from pristine PTFE. It is considered that this is one of reasons why the adsorption mass in the thin film deposited by the r.f. sputtering was higher than that in the thin film deposited by the spin coating.

Iwamori, Satoru; Miyamoto, Takaaki; Ikeda, Yuki; Ohnishi, Yasutaka; Noda, Kazutoshi

129

Etching characteristics of high-k dielectric HfO{sub 2} thin films in inductively coupled fluorocarbon plasmas  

SciTech Connect

Inductively coupled fluorocarbon (CF{sub 4}/Ar and C{sub 4}F{sub 8}/Ar) plasmas were used to etch HfO{sub 2}, which is a promising high-dielectric-constant material for the gate of complementary metal-oxide-semiconductor devices. The etch rates of HfO{sub 2} in CF{sub 4}/Ar plasmas exceeded those in C{sub 4}F{sub 8}/Ar plasmas. The tendency for etch rates to become higher in fluorine-rich (high F/C ratio) conditions indicates that HfO{sub 2} can be chemically etched by fluorine-containing species. In C{sub 4}F{sub 8}/Ar plasmas with a high Ar dilution ratio, the etch rate of HfO{sub 2} increased with increasing bias power. The etch rate of Si, however, decreased with bias power, suggesting that the deposition of carbon-containing species increased with increasing the power and inhibited the etching of Si. The HfO{sub 2}/Si selectivity monotonically increased with increasing power, then became more than 5 at the highest tested bias power. The carbon-containing species to inhibit etching of Si play an important role in enhancing the HfO{sub 2}/Si selectivity in C{sub 4}F{sub 8}/Ar plasmas.

Takahashi, Kazuo; Ono, Kouichi; Setsuhara, Yuichi [Department of Aeronautics and Astronautics, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan)

2005-11-15

130

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

PubMed

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

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

2013-02-18

131

Neutralization of methyl cation via chemical reactions in low-energy ion-surface collisions with fluorocarbon and hydrocarbon self-assembled monolayer films.  

PubMed

Low-energy ion-surface collisions of methyl cation at hydrocarbon and fluorocarbon self-assembled monolayer (SAM) surfaces produce extensive neutralization of CH3+. These experimental observations are reported together with the results obtained for ion-surface collisions with the molecular ions of benzene, styrene, 3-fluorobenzonitrile, 1,3,5-triazine, and ammonia on the same surfaces. For comparison, low-energy gas-phase collisions of CD3+ and 3-fluorobenzonitrile molecular ions with neutral n-butane reagent gas were conducted in a triple quadrupole (QQQ) instrument. Relevant MP2 6-31G*//MP2 6-31G* ab initio and thermochemical calculations provide further insight in the neutralization mechanisms of methyl cation. The data suggest that neutralization of methyl cation with hydrocarbon and fluorocarbon SAMs occurs by concerted chemical reactions, i.e., that neutralization of the projectile occurs not only by a direct electron transfer from the surface but also by formation of a neutral molecule. The calculations indicate that the following products can be formed by exothermic processes and without appreciable activation energy: CH4 (formal hydride ion addition) and C2H6 (formal methyl anion addition) from a hydrocarbon surface and CH3F (formal fluoride addition) from a fluorocarbon surface. The results also demonstrate that, in some cases, simple thermochemical calculations cannot be used to predict the energy profiles because relatively large activation energies can be associated with exothermic reactions, as was found for the formation of CH3CF3 (formal addition of trifluoromethyl anion). PMID:12387320

Somogyi, Arpád; Smith, Darrin L; Wysocki, Vicki H; Colorado, Ramon; Lee, T Randall

2002-10-01

132

Etching mechanisms of Si and SiO{sub 2} in inductively coupled fluorocarbon plasmas: Correlation between plasma species and surface etching  

SciTech Connect

Etching mechanisms of silicon and silicon oxide in a fluorocarbon environment are studied in an ICP reactor. Optimization of the process for deep etching of SiO{sub 2} with a Si mask has been discussed in a previous article. In this article, adequate plasma conditions are chosen both (a) to allow separation of parametric variables and (b) to get appreciable variation of the different plasma and surface experimental results versus parameters. Hence, pressure, source power, ion energy, and subsequently ion flux are kept constant. The influences of the gas composition and the residence time (varying gas flow rate) are studied. We show that silicon etching depends both on the atomic fluorine concentration in the plasma and of the fluorocarbon blocking layer at the surface. We pay particular attention to the formation of the fluorocarbon overlayer. We establish that the thickness of this layer is linked to the plasma species through the (C+H)/F ratio, calculated from the radical densities in the gas, taking into account the etching-deposition competition. Concerning oxide etching in the so-called sputtering regime, we show that the overlayer detected by x-ray photoelectron spectroscopy does not control the etching mechanism and seems to be an interaction layer between plasma and oxide rather than a blocking layer. We also establish a linear relation between oxide etch yield and the average F/C ratio calculated from the ion densities indicating that the radical species are not a limiting factor in the oxide etching mechanism. Finally, from these results for oxide and silicon etching, a correlation between plasma species and the evolution of the etch rates versus ion energy is done by varying gas composition and residence time.

Gaboriau, F.; Fernandez-Peignon, M-C.; Cartry, G.; Cardinaud, Ch. [Laboratoire des Plasmas et des Couches Minces, IMN-CNRS-Universite de Nantes, 2 rue de la Houssiniere, BP 32229, 44322 Nantes Cedex 3, (France)

2005-03-01

133

Modeling and Simulation of Plasma-Induced Damage Distribution during Hole Etching of SiO2 over Si Substrate by Fluorocarbon Plasma  

NASA Astrophysics Data System (ADS)

We developed a plasma etching simulation with our new concept in order to predict the distribution of plasma-induced damage during contact hole etching of SiO2 over Si substrate using fluorocarbon plasma (C4F8/O2/Ar). Our model included plasma database, gas transport (direct and indirect fluxes of ions and radicals), surface reaction considering depth effect, and damage distribution. We could demonstrate how to evolve the Si damage in main and overetching steps, which is realistically difficult to measure. Our results show that polymer thickness, overetching time, and etched profile should be carefully controlled to reduce physical damage.

Kuboi, Nobuyuki; Tatsumi, Tetsuya; Kobayashi, Shoji; Kinoshita, Takashi; Komachi, Jun; Fukasawa, Masanaga; Ansai, Hisahiro

2012-12-01

134

Ameliorating effects of fluorocarbon emulsion on sickle red blood cell-induced obstruction in an ex vivo vasculature.  

PubMed

In sickle cell (SS) vaso-occlusion, the culminating event is blockage of blood vessels by sickled red blood cells (SS RBCs). As shown in animal models, SS RBC-induced vaso-occlusion is often partial, allowing for a residual flow, hence oxygen delivery to partially occluded vessels could reduce vaso-occlusion. The efficacy of an oxygenated perflubron-based fluorocarbon emulsion (PFE) was tested for its anti-vaso-occlusive effects in the ex vivo mesocecum vasculature of the rat. Microvascular obstruction was induced by the infusion of deoxygenated SS RBCs into ex vivo preparations with or without pretreatment with platelet-activating factor (PAF). PAF induced enhanced SS RBC-endothelium interactions, leading to greater vaso-occlusion. Microvascular blockage resulted in increased peripheral resistance units (PRU). Deoxygenated SS RBCs caused a persistent 1.5-fold PRU increase in untreated preparations and approximately a 2-fold PRU increase in PAF-treated preparations. The greater PRU in PAF-treated preparations was caused by widespread adhesion and postcapillary blockage. Oxygenated PFE, but not deoxygenated PFE, resulted in PRU decreases to baseline values in both groups of experiments (with or without PAF). The PRU decrease caused by oxygenated PFE infusion was caused by unsickling of SS RBCs in partially occluded vessels, with no antiadhesive effect on already adherent SS RBCs as assessed by intravital microscopy. PFE had no effect on vascular tone. The efficacy of PFE appears to result from its greater capacity to dissolve oxygen (10-fold higher than plasma). The dislodgement of trapped SS RBCs and an increase in wall shear rates will help reverse the partial obstruction. Thus, oxygenated PFE is capable of reducing SS RBC-induced vaso-occlusion, and further development of this approach is advisable. PMID:11698300

Kaul, D K; Liu, X; Nagel, R L

2001-11-15

135

Improvements in the technique of vascular perfusion-fixation employing a fluorocarbon-containing perfusate and a peristaltic pump controlled by pressure feedback.  

PubMed

A new improved technique for whole-body perfusion-fixation of rats and other small animals is described. The driving force is a peristaltic pump which is feedback regulated by a pressure transducer that monitors the blood-perfusion pressure in the left ventricle of the heart. The primary perfusate-fixative is composed of a blood substitute--13.3% oxygenated fluorocarbon FC-75--in 0.05 M cacodylate buffer (pH 7.4) with a 2% glutaraldehyde. The secondary perfusate-fixative is composed of 2% glutaraldehyde in 0.05 M cacodylate buffer (pH 7.4) with 20 mM CaCl2. A double-barrelled, self-holding cannula is used to cannulate the heart; the outer and inner barrels of the cannula are connected to the peristaltic pump and to the pressure transducer, respectively. The tissue oxygen tension in the rat is monitored by a subcutaneous oxygen electrode. Measurements showed that tissue hypoxia/anoxia did not develop before or during the perfusion-fixation. Thus, the technique permits study of specimens which do not exhibit fixation gradients and do not contain cells fixed in a state of asphyxia. This is substantiated by electron micrographs of cells from different organs, revealing new fine structural elements. By adding oxygenated fluorocarbon to glutaraldehyde perfusate-fixatives, enough oxygen is made accessible for cellular respiration as well as for the oxygen-consuming chemical reactions of glutaraldehyde with the tissue. Data on anaesthesia, operative manoeuvres, mechanical components of the system, preparation of fixatives and flow of the perfusate-fixatives are furnished and discussed. PMID:8289232

Rostgaard, J; Qvortrup, K; Poulsen, S S

1993-11-01

136

Role of chamber dimension in fluorocarbon based deposition and etching of SiO{sub 2} and its effects on gas and surface-phase chemistry  

SciTech Connect

It is well understood that chamber geometry is an influential factor governing plasma processing of materials. Simple models suggest that a large fraction of this influence is due to changes in basic plasma properties, namely, density, temperature, and potential. However, while such factors do play an important role, they only partly describe the observed differences in process results. Therefore, to better elucidate the role of chamber geometry in this work, the authors explore the influence of plasma chemistry and its symbiotic effect on plasma processing by decoupling the plasma density, temperature, and potential from the plasma-surface (wall) interactions. Specifically, a plasma system is used with which the authors can vary the chamber dimension so as to vary the plasma-surface interaction directly. By varying chamber wall diameter, 20-66 cm, and source-platen distance, 4-6 cm, the etch behavior of SiO{sub 2} (or the deposition behavior of fluorocarbon polymer) and the resulting gas-phase chemistry change significantly. Results from in situ spectroscopic ellipsometry show significant differences in etch characteristics, with etch rates as high as 350 nm/min and as low as 75 nm/min for the same self-bias voltage. Fluorocarbon deposition rates are also highly dependent on chamber dimension and vary from no net deposition to deposition rates as high as 225 nm/min. Etch yields, however, remain unaffected by the chamber size variations. From Langmuir probe measurements, it is clear that chamber geometry results in significant shifts in plasma properties such as electron and ion densities. Indeed, such measurements show that on-wafer processes are limited at least in part by ion flux for high energy reactive ion etch. However, in situ multipass Fourier transform infrared spectroscopy reveals that the line-averaged COF{sub 2}, SiF{sub 4}, CF{sub 2}, and CF{sub 3} gas-phase densities are also dependent on chamber dimension at high self-bias voltage and also correlate well to the CF{sub x} overlayer stoichiometry under deposition conditions.

Joseph, E. A.; Zhou, B.-S.; Sant, S. P.; Overzet, L. J.; Goeckner, M. J. [Plasma Science and Applications Lab, Department of Electrical Engineering, University of Texas at Dallas, M/S RL 10, 800 W. Campbell Rd., Richardson, Texas 75080 (United States)

2008-05-15

137

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

SciTech Connect

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.

Bai Bo; Sawin, Herbert H.; Cruden, Brett A. [Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Department of Chemical Engineering and Electrical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); NASA Ames Center for Nanotechnology, Moffett Field, California 94035 (United States)

2006-01-01

138

Investigation of the roles of gas-phase CF2 molecules and F atoms during fluorocarbon plasma processing of Si and ZrO2 substrates  

NASA Astrophysics Data System (ADS)

The molecular-level chemistry involved in the processing of silicon and zirconia substrates by inductively coupled fluorocarbon (FC) plasmas produced from CF4 and C2F6 precursors has been explored. The roles of gas-phase excited, neutral, and ionic species, especially CF2 and F, were examined as they contribute to FC film formation and substrate etching. The surface reactivity of CF2 radicals in C2F6 plasmas has a dependence on substrate material and plasma system, as measured by our imaging of radicals interacting with surfaces (IRIS) technique. Relative concentrations of excited state species are also dependent upon substrate type. Moreover, differences in the nature and concentrations of gas-phase species in CF4 and C2F6 plasmas contribute to markedly different surface compositions for FC films deposited on substrates as revealed from x-ray photoelectron spectroscopic analysis. These data have led to the development of a scheme that illustrates the mechanisms of film formation and destruction in these FC/substrate systems with respect to CF2 and F gas-phase species and also Si and ZrO2 substrates.

Cuddy, Michael F.; Fisher, Ellen R.

2010-08-01

139

Measurement of Fluorocarbon Radicals Generated from C4F8/H2 Inductively Coupled Plasma: Study on SiO2 Selective Etching Kinetics  

NASA Astrophysics Data System (ADS)

The kinetics of highly selective SiO2 etching were studied on the basis of appearance mass spectroscopy (AMS) measurement of fluorocarbon radicals generated from C4F8/H2 inductlvely coupled plasma (ICP). Results obtained by varying of H2 concentration in C4F8, total pressure and RF power implied that CF1 radical played a major role in the polymer film deposition. In particular, radical measurements carried out by varying the length of a quartz tube which was set in front of an inlet of radicals effusing into AMS revealed that CF2 radical might not contribute to the polymer deposition and that the sticking probability of CF1 radical was reduced considerably in the presence of hydrogen. It was also observed that in etching using a capillary plate as a high-aspect-ratio mask, the carbon-rich polymer film is deposited on the Si bottom surface in the presence of hydrogen at high CF1/CF2 radical density ratio. Accordingly, CF1 radicals whose surface loss is suppressed in the presence of hydrogen are likely to arrive at deep the bottom surface, forming the carbon-rich polymer by reaction of hydrogen with fluorine from CF1 radicals.

Kubota, Kazuhiro; Matsumoto, Hiroyuki; Shindo, Haruo; Shingubara, Shoso; Horiike, Yasuhiro

1995-04-01

140

Enhancement of the antitumor effect of glucose oxidase by combined administration of hydrogen peroxide decomposition inhibitors together with an oxygenated fluorocarbon.  

PubMed

Glucose oxidase (GO) catalyzes the conversion of beta-D-glucose and molecular oxygen to D-glucono-delta-lactone and H2O2. H2O2 produced by GO was effective in preventing tumor growth in mice bearing not only ascites tumor but also solid tumor. The effect of GO was enhanced by the combined administration of catalase inhibitors such as 3-aminotriazole, hydroxylamine and sodium azide or the GSH synthesis inhibitor buthionine-(S,R)-sulfoximine in vivo. The cytolytic activity of GO against T-24 cultured cells in vitro was also enhanced by addition of these inhibitors together with GO. In the peritoneal cavity of mice the antitumor effect of GO seemed to be dependent on the amount of oxygen released from oxygenated fluorocarbon-43 (FC-O2), an oxygen-supplying substance. Furthermore, the combined administration of H2O2-decomposing enzyme inhibitors and FC-O2 synergistically enhanced the antitumor effect of GO. These results suggest that GO is suitable for antitumor chemotherapy and that the use of inhibitors of H2O2-decomposing enzymes and FC-O2 potentiated the GO therapy. PMID:1910030

Higuchi, Y; Shoin, S; Matsukawa, S

1991-08-01

141

Reliable Stimulated Brillouin Scattering Compression of Nd:YAG Laser Pulses with Liquid Fluorocarbon for Long-Time Operation at 10 Hz.  

PubMed

Stokes pulses of high energy and high-average power were obtained by stimulated Brillouin scattering (SBS) compression of long Nd:YAG laser pulses. The SBS medium used in the single-cell compressor was liquid ultrafiltered Fluorinert FC-75 fluorocarbon. An output pulse duration of 0.9 ns and a peak-power enhancement by 1 order of magnitude were observed for 10-ns, 0.57-J input pulses at a 10-Hz repetition rate. The compressor internal SBS efficiency reached a value of eta(SBS) = 94% and the overall device efficiency a value of eta(dev) = 87%; both values are the highest reported so far to the best of our knowledge. The simple single-cell SBS geometry provided excellent energy and pointing stability of the Stokes pulse. Its temporal shape turned out to be somewhat less stable. The SBS process also partially improved the laser beam quality. The Stokes pulses proved to be capable of generating radiation in the extreme-ultraviolet and soft-x-ray regions over a period of two months without any significant output deterioration. PMID:18301529

Kmetik, V; Fiedorowicz, H; Andreev, A A; Witte, K J; Daido, H; Fujita, H; Nakatsuka, M; Yamanaka, T

1998-10-20

142

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

PubMed

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. PMID:23330687

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

2013-01-01

143

Synthesis of transparent fluorocarbon elastomers: effect of crosslinker type and electron beam irradiation level on physical and mechanical behavior. [Elastomers - Viton GLT-copolymer of vinylidene fluoride, perfluoro(methyl vinyl ether) and tetrafluoroethylene; triallyl isocyanurate  

SciTech Connect

Saturated fluorocarbon elastomers are very resistant to chemical reactions, including those of a crosslinking nature. In order to study proper methods of preparing these materials, Viton GLT was mixed with various levels of trimethylol propane trimethacrylate, TMPTM, and triallyl isocyanurate, Diak No. 7. After molding, the materials were subjected to electron beam irradiation. The glass transition, rubbery modulus, viscoelastic behavior, and equilibrium swelling were used to characterize the materials as a function of crosslinker and irradiation level. In general, the modulus and gel fraction increased with both crosslinker content and irradiation level. Mixtures of both crosslinking monomers produced an unexpected synergism, yielding higher tensile strength, and earlier onset of gelation.

Kaiser, R.J.; Miller, G.A.; Thomas, D.A.; Sperling, L.H.

1982-03-01

144

Synthesis and reactivity of low-coordinate iron(II) fluoride complexes and their use in the catalytic hydrodefluorination of fluorocarbons.  

PubMed

Transition metal fluoride complexes are of interest because they are potentially useful in a multitude of catalytic applications, including C-F bond activation and fluorocarbon functionalization. We report the first crystallographically characterized examples of molecular iron(II) fluorides: [L(Me)Fe(mu-F)]2 (1(2)) and L(tBu)FeF (2) (L = bulky beta-diketiminate). These complexes react with donor molecules (L'), yielding trigonal-pyramidal complexes L(R)FeF(L'). The fluoride ligand is activated by the Lewis acid Et2O.BF3, forming L(tBu)Fe(OEt2)(eta1-BF4) (3), and is also silaphilic, reacting with silyl compounds such as Me3SiSSiMe3, Me3SiCCSiMe3, and Et3SiH to give new thiolate L(tBu)FeSSiMe3 (4), acetylide L(tBu)FeCCSiMe3 (5), and hydride [L(Me)Fe(mu-H)]2 (6(2)) complexes. The hydrodefluorination (HDF) of perfluorinated aromatic compounds (hexafluorobenzene, pentafluoropyridine, and octafluorotoluene) with a silane R3SiH (R3 = (EtO)3, Et3, Ph3, (3,5-(CF3)2C6H3)Me2) is catalyzed by addition of an iron(II) fluoride complex, giving mainly the singly hydrodefluorinated products (pentafluorobenzene, 2,3,5,6-tetrafluoropyridine, and alpha,alpha,alpha,2,3,5,6-heptafluorotoluene, respectively) in up to five turnovers. These catalytic perfluoroarene HDF reactions proceed with activation of the C-F bond para to the most electron-withdrawing group and are dependent on the degree of fluorination and solvent polarity. Kinetic studies suggest that hydride generation is the rate-limiting step in the HDF of octafluorotoluene, but the active intermediate is unknown. Mechanistic considerations argue against oxidative addition and outer-sphere electron transfer pathways for perfluoroarene HDF. Fluorinated olefins are also hydrodefluorinated (up to 10 turnovers for hexafluoropropene), most likely through a hydride insertion/beta-fluoride elimination mechanism. Complexes 1(2) and 2 thus provide a rare example of a homogeneous system that activates C-F bonds without competitive C-H activation and use an inexpensive 3d transition metal. PMID:15913376

Vela, Javier; Smith, Jeremy M; Yu, Ying; Ketterer, Nicole A; Flaschenriem, Christine J; Lachicotte, Rene J; Holland, Patrick L

2005-06-01

145

Multilayer formation of the fluoroalkanol-?-hydrogenated fluorocarbon mixture at the hexane/water interface studied by interfacial tensiometry and X-ray reflection.  

PubMed

Novel multilayer formation of fluorocarbon compounds at the hexane/water interface was investigated from the viewpoint of intermolecular interaction and miscibility of molecules in the adsorbed film. The two kinds of mixed systems were employed: 1H,1H,2H,2H-perfluorododecanol (FC12OH)-1H-perfluorodecane (HFC10) (System A) and 1-icosanol (C20OH)-HFC10 (System B). The interfacial tension ? between the hexane solution and water was measured as a function of total concentration m and the composition of HFC10 in the mixture X(2) at 298.15 K under atmospheric pressure. X-ray reflectivity (XR) measurement was performed at BL37XU in SPring-8 as a function of scattering vector Q(z). In both systems, the ? vs m curves except for the pure HFC10 system have a break at low concentrations, which corresponds to the gaseous-condensed monolayer transition for System A and the expanded-condensed monolayer for System B. The remarkable difference between the two systems was that the curves in a limited bulk composition range (0.45 ? X(2) ? 0.9) of System A show another break at high concentrations close to the solubility limit. The total interfacial density above this break point was around 7-11 ?mol m(-2), suggesting the spontaneous molecular piling to form a multilayer. The phase diagrams of adsorption in the condensed monolayer indicated that the film composition of HFC10 is negative in System B but definitely positive above X(2) ? 0.45 in System A. This clearly shows that HFC10 molecules are miscible with FC12OH but immiscible with C20OH in the condensed monolayer. Thus, it is likely that the mixing of HFC10 with FC12OH in the condensed monolayer induces multilayer formation. The X-ray reflectivity normalized by Fresnel reflectivity R/R(F) vs Q(z) plot in the condensed monolayer of System A was fitted by a one-slab model with uniform electron density and thickness. The electron density profile was almost the same as that of the pure FC12OH system. The plot in the multilayer, on the other hand, was fitted well by the two-slab model with different electron densities and thicknesses. The electron density profile showed that the multilayer consists of two layers, one of which has slightly higher electron density than the bulk hexane phase and piles on the lower layer with almost the same electron density as the condensed FC12OH monolayer. PMID:23110594

Takiue, Takanori; Tottori, Takuya; Tatsuta, Kazuo; Matsubara, Hiroki; Tanida, Hajime; Nitta, Kiyofumi; Uruga, Tomoya; Aratono, Makoto

2012-11-09

146

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

SciTech Connect

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

Cuddy, Michael F.; Fisher, Ellen R. [Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872 (United States)

2010-08-15

147

Selective etching of high-k HfO{sub 2} films over Si in hydrogen-added fluorocarbon (CF{sub 4}/Ar/H{sub 2} and C{sub 4}F{sub 8}/Ar/H{sub 2}) plasmas  

SciTech Connect

Inductively coupled hydrogen-added fluorocarbon (CF{sub 4}/Ar/H{sub 2} and C{sub 4}F{sub 8}/Ar/H{sub 2}) plasmas were used to etch HfO{sub 2}, which is a promising high-dielectric-constant material for the gate of complementary metal-oxide-semiconductor devices. The etch rates of HfO{sub 2} and Si were drastically changed depending on the additive-H{sub 2} flow rate in C{sub 4}F{sub 8}/Ar/H{sub 2} plasmas. The highly selective etching of HfO{sub 2} over Si was done in the condition with an additive-H{sub 2} flow rate, where the Si surface was covered with the fluorocarbon polymer. The results of x-ray photoelectron spectroscopy indicated that the carbon content of the selectively etched HfO{sub 2} surface was extremely low compared with the preetched surface contaminated by adventitious hydrocarbon in atmosphere. In the gas phase of the C{sub 4}F{sub 8}/Ar/H{sub 2} plasmas, Hf hydrocarbide molecules such as metal-organic compounds and Hf hydrofluoride were detected by a quadrupole mass analyzer. These findings indicate that the fluorine species, carbon, and hydrogen can work to etch HfO{sub 2} and that the carbon species also plays an important role in selective etching of HfO{sub 2} over Si.

Takahashi, Kazuo; Ono, Kouichi [Department of Aeronautics and Astronautics, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan)

2006-05-15

148

Flammability Limits of Fuel/Fluorocarbon Azeotropes.  

National Technical Information Service (NTIS)

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...

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

1981-01-01

149

Flammability limits of fuel/fluorocarbon azeotropes  

SciTech Connect

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.

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

1981-02-10

150

2-D Temperature Mapping in Fluorocarbon Plasmas  

SciTech Connect

Two-dimensional maps of rotational temperature in CF4 plasmas were determined using planar laser-induced fluorescence measurements of CF A2{sigma}+ - X2{pi} (1,0). Rotational temperatures are expected to be in equilibrium with gas temperatures under the present conditions. Experiments were performed in a capacitively-coupled, parallel-plate reactor at pressures from 27 Pa to 107 Pa and powers of 10 W to 30 W. The effects of electrode cooling and having a wafer present were also examined. Measured temperatures ranged between 273 K{+-}15 K and 480 K{+-}15 K. The strong temperature gradients found in these plasmas can have serious effects on density measurements that probe a single rotational level, as well as on reaction rate constants and interpretation of density gradients.

Steffens, Kristen L.; Sobolewski, Mark A. [Process Measurements Division, National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States)

2005-09-09

151

Effects of fluorocarbons on biological systems  

Microsoft Academic Search

The halogenated hydrocarbons, in particular, the fluoroalkane gases of Freons (generic name, halons), are widely used today in various industrial and household applications because they are felt to be relatively non-toxic. The effects of Freon-11 (trichlorofluoromethan), Freon-21 (dichlorofluoromethane), Freon-22 (monochlorodifluoromethane), and Halothane (2-bromo-2-chloro-1,1,1-trifluoroethane) were tested on several different biological systems including eight species of bacteria, two species of plants, and

J. Healy; R. T. S. Lee; D. Perrotta; O. W. Van Auken

1974-01-01

152

Nonclassical gasdynamic region of selected fluorocarbons  

NASA Astrophysics Data System (ADS)

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.

Guardone, A.; Argrow, B. M.

2005-11-01

153

Fluorocarbon Ether Bis(o-Aminophenol) Compounds.  

National Technical Information Service (NTIS)

The patent application describes two compounds: 1,14-bis(3-amino-4-hydroxyphenyl)-perfluoro-5,10-dimethyl-3,6,9,12- tetraoxatetradecane and 1,17-bis(3-amino-4-hydroxyphenyl)perfluoro-3,6,9,15- tetraoxaheptadecane. The compounds are useful as monomers in s...

R. C. Evers

1975-01-01

154

Fluorocarbon Ether Bis(O-Aminophenol) Compounds.  

National Technical Information Service (NTIS)

As new compositions of matter, 1,14-bis(3-amino-4-hydroxyphenyl)perfluoro-5, 10-dimethyl-3,6,9,12-tetraoxatetradecane and 1,17-bis(3-amino-4-hydroxyphenyl)perfluoro-3,6,9,15- tetraoxaheptadecane. The compounds are useful as monomers in synthesizing perflu...

R. C. Evers

1977-01-01

155

Determination of Fluorocarbon Ether Autoxidative Degradation Mechanism.  

National Technical Information Service (NTIS)

Elucidation of mechanisms operative in thermal oxidative degradation of hexafluoropropene oxide derived polyethers and the effect of metals and anti-oxidant/anti-corrosion additives on this process are reported. Thermal oxidative instability of the commer...

K. L. Paciorek R. H. Kratzer J. Kaufman J. H. Nakahara

1977-01-01

156

Research on Synthesis of Unsaturated Fluorocarbon Compounds.  

National Technical Information Service (NTIS)

Synthesis of a variety of fluorine-containing compounds was studied. A convenient synthesis of perfluoroallyl halides was developed. Lewis acid catalyzed addition of haloalkanes to olefins resulted in new fluoroolefins. A series of fluorine monomers were ...

P. Tarrant O. J. Stewart F. G. Drakesmith D. Sayers J. Heyes

1967-01-01

157

Research on Synthesis of Unsaturated Fluorocarbon Compounds.  

National Technical Information Service (NTIS)

Allyl magnesium bromide has been found to react with a number of fluoroolefins to give reasonable yields of the 1,4-dienes. The reaction of fluoroolefins with vinyl organometallics and the mono- and di-metallic acetylenes proved unsuccesful. The codimeriz...

P. Tarrant J. Heyes D. Sayers W. Oliver A. C. Wright

1964-01-01

158

Fluorocarbon-modified water-soluble cellulose derivatives  

Microsoft Academic Search

1,1-Dihydroperfluorobutyl,1,1-dihydroperfluorooctyl, and octyl derivatives of (hydroxyethyl)-cellulose (HEC) were prepared by reaction of the Na salt of HEC in aqueous isopropyl alcohol with 1,1-dihydroperfluorobutyl or octyl p-toluenesulfonate (4 or 5), with 1,1-dihydroperfluorobutyl or octyl glycidyl ether or (8 or 9), and with octyl glycidyl ether (12). The degrees of substitution of HEC were determined using [sup 19]FNMR and varied between 0.023

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

1993-01-01

159

Piezoelectricity and dynamic characteristics of laminated fluorocarbon films  

Microsoft Academic Search

The piezoelectrets made of porous polytetrafluoroethylene (PTFE) and nonporous fluoroethylenepropylene (FEP) layers are prepared by using a hot-pressing method. The dependence of the quasi-static piezoelectric d33-coefficients of such films on the grid voltage during the corona charging is investigated. The thermal stability of d33-coefficients for the films is characterized by the isothermal method. The Young's Modulus and dynamic d33-coefficient are

Xiaoqing Zhang; Jinfeng Huang; Xuewen Wang; Zhongfu Xia

2010-01-01

160

VUV excimer laser-materials interactions with fluorocarbon polymers  

NASA Astrophysics Data System (ADS)

Particle emission from transparent wide bandgap materials at laser fluences below the threshold for optical breakdown can provide important insight on interactions at the higher fluences employed for surface modification, machining, and laser ablation deposition. We present recent studies of ion and neutral molecule emission from polytetrafluorethylene [(C2F4)N---PTFE---Teflon] and polyvinylidene fluoride [(CH2CF2)N---PVDF] during nanosecond pulsed 157-nm excimer laser irradiation. The chemical and electrical properties of these materials play important roles in many technologies. In PTFE, the primary mechanism for material removal involves bond scission along the backbone of the polymer. In PVDF, HF emission is accompanied by carbonization of the irradiated region. High-energy positive and negative ions are observed from both materials under 157-nm irradiation. We describe critical measurements that reveal the physics and chemistry underlying these processes.

Dickinson, Tom; George, Sharon; Langford, Steve

2009-03-01

161

Role of surface temperature in fluorocarbon plasma-surface interactions  

SciTech Connect

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.

Nelson, Caleb T.; Overzet, Lawrence J.; Goeckner, Matthew J. [Department of Electrical Engineering, University of Texas at Dallas, PO Box 830688, Richardson, TX 75083 (United States)

2012-07-15

162

Use of fluorocarbons in the cooling of LHC experiments  

Microsoft Academic Search

Perfluorochemicals sold by 3M under the trade name 3M Fluorinert Electronic Liquids have been used for many years as heat transfer media in a variety of industries. The suitability of these liquids for the cooling of LHC experiment originates from their high dielectric strength as well as from their chemical stability under ionizing radiation. The Fluorinerts are clear, colorless, non-flammable

M Pimenta dos Santos

2003-01-01

163

Fluosilicate impurity in infrared spectra of pyrolyzates of fluorocarbon resins  

Microsoft Academic Search

Infrared spectra of fluororesin pyrolyzates, obtained by the conventional decomposition of samples on a commercial pyrolyzer employing a Nichrome filament (e.g., Barnes Engineering Company pyrolyzer model PY-2), generally contain fluosilicate (SiFâ\\/sup 2 -\\/) absorption maxima at 730 and 480 cm⁻¹. The presence of SiFâ\\/sup 2 -\\/ in pyrolyzates was assumed to be derived from siliceous matter in the fluororesin until

R. S. Cichorz; C. E. Gies

1980-01-01

164

Collagen Synthesized in Fluorocarbon Polymer Implant in the Rabbit Cornea  

Microsoft Academic Search

The integration of microporous polymer into tissues is of great interest for the production of keratoprosthetic devices. Our previous studies showed functional differentiated cells and collagen synthesis in the pore of an expanded polytetrafluoroethylene implant. This study identifies and quantifies collagen types synthesized in the implant. Expanded polytetrafluoroethylene polymers were implanted in the rabbit corneas. The collagen extracted from the

ISABELLE DRUBAIX; JEAN-MARC LEGEAIS; NAYLA MALEK-CHEHIRE; MICHÈLE SAVOLDELLI; MAURICE MÉNASCHE; LADISLAS ROBERT; GILLES RENARD; YVES POULIQUEN

1996-01-01

165

Fluorocarbon-modified water-soluble cellulose derivatives  

SciTech Connect

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

Hwang, F.S.; Hogen-Esch, T.E. (Univ. of Southern California, Los Angeles, CA (United States). Loker Hydrocarbon Research Inst. and Dept. of Chemistry)

1993-06-07

166

Structure-Property Relationships in Bibenzoxazole Polymers Containing Fluorocarbon Linkages.  

National Technical Information Service (NTIS)

A series of bibenzoxazole polymers has presented a unique opportunity to determine relationships between physical transitions and molecular structure. The results of oscillatory thermomechanical experiments show two glassy-state and a glass transition as ...

J. K. Gillham C. K. Schoff

1976-01-01

167

Halogen bonding driven self-assembly of fluorocarbons and hydrocarbons  

Microsoft Academic Search

Halogen bonding, the interaction between halogen atoms and lone pair possessing atoms, overcomes the low affinity existing between perfluorocarbon and hydrocarbon derivatives. This interaction effectively drives the self-assembly of materials wherein perfluorocarbon and hydrocarbon layers alternate thanks to a remarkable module segregation. The approach has been exploited in supramolecular polymer coating.

Pierangelo Metrangolo; Tullio Pilati; Giuseppe Resnati; Andrea Stevenazzi

2003-01-01

168

Protection from venous air embolism with fluorocarbon emulsion FC-43.  

PubMed

Intraoperative venous air embolism (VAE) occurs frequently in some surgical settings and may cause devastating hemodynamic consequences. Perfluorocarbon emulsions have been investigated as artificial oxygen carrying medias. They also have the properties of enhanced nitrogen solubility and a small particle size. FC-43 (Oxypherol, Alpha Therapeutic Corp., Los Angeles, California) was compared to three other volume expanders in 91 New Zealand White laboratory rabbits exposed to continuous VAE. The animals were anesthetized and ventilated by one of four modalities. They then received one of the volume expanders at 20 cc/kg over 30 min. After a 10-min stabilization period, a constant femoral venous air infusion (0.25 cc/kg/min) was begun and continued until death. Time until death, total volume of air infused, femoral arterial pressure, central venous pressure, and ECG (Lead II) were recorded. Death was defined as the cessation of pulsatile blood pressure. Arterial and central venous gases were analyzed pre and post volume expansion and at intervals of every 5 min after the beginning of the femoral air infusion. Results showed a significant prolongation of life for the animals receiving FC-43 at 10 and 20 cc/kg as a volume expander and mechanically ventilated with 100% oxygen as compared to all other groups (P less than 0.05). PaO2 and PvO2 were consistently higher in the group receiving FC-43 as a volume expander. Central venous pressure was lower during air embolism in the FC-43 group. The mechanism for the enhanced survivability of rabbits pretreated with FC-43 volume expansion exposed to VAE is under further investigation. PMID:3773504

Spiess, B D; McCarthy, R; Piotrowski, D; Ivankovich, A D

1986-10-01

169

Aerosols and Fluorocarbons - A National Telephone Survey on Consumer Opinions.  

National Technical Information Service (NTIS)

This survey measured consumer attitudes toward safety, health, and the environment in general, and aerosol products in particular. The objectives were to determine consumer awareness of unsafe household products; the level of information supporting consum...

1976-01-01

170

Synthesis of Unusual Perfluorocarbon Ethers and Amines Containing Bulky Fluorocarbon Groups: New Biomedical Materials.  

National Technical Information Service (NTIS)

The reactions of elemental fluorine with structurally crowded hydrocarbon ethers and amines have been studied. The perfluorinated products are currently of interest in biomedical or electronic industrial applications. The 19F and 13C(19F) (19F decoupled) ...

H. N. Huang D. F. Persico R. J. Lagow L. C. Clark

1988-01-01

171

Unique liquid crystal behavior in water of anionic fluorocarbon-hydrocarbon hybrid surfactants containing oxyethylene units.  

PubMed

This study reports the unique aqueous lyotropic liquid crystal behavior of an anionic hybrid surfactant, 8F-B2ES, which has 2-[2-(butyloxy)ethyloxy]ethyl and 1H,1H,2H,2H-perfluorodecyl tails. An 8F-B2ES-analog hybrid surfactant with no oxyethylene units (8F-DeS) and a symmetric fluorinated double-tail surfactant with two 2-(1H,1H,2H,2H-perfluorohexyloxy)ethyl tails (4FEOS) were used as control surfactants in examining the effects of the oxyethylene units and of the hybrid structure on the liquid crystal behavior. Polarized microscopic observations showed the formation of a lamellar liquid crystal phase for each surfactant/water mixture at surfactant concentrations higher than 10 wt.%. In the case of the 30 wt.% 8F-B2ES/water mixture, two types of spherical aggregates were observed at temperatures higher than 40 °C: one was a typical lamella liquid crystal with a maltese cross-texture, and the other was optically isotropic. Interestingly, when the 8F-B2ES lamellar phase was cooled to below 40 °C, the lamellar aggregates were distorted and the isotropic droplets became anisotropic. As this unique liquid crystal behavior was not observed for aqueous mixtures of the control surfactants, the oxyethylene units in the hybridized hydrocarbon tail play an important role in the behavior. This study also examined the effect of the oxyethylene units on microenvironmental polarity in the hybrid surfactant bilayer via fluorescence spectral measurements of pyrene solubilized in each lamellar phase. The polarity of the 8F-B2ES bilayer at 70 °C was found to be that of a hydrocarbon surfactant lamellar phase, and increased gradually with decreasing temperature. The polarity became the same as that of hydrophilic spherical micelles below 40 °C, despite the presence of the lamellar aggregates. Since the polarity in the 8F-DeS bilayer was independent of temperature, and as low as that of a typical hydrocarbon surfactant bilayer, hydration of the 8F-B2ES oxyethylene units would increase the polarity, and then loosen the 8F-B2ES packing within the bilayer. This probably led to distortion of the lamellar aggregates. PMID:21402384

Sagisaka, Masanobu; Fujita, Yoshie; Shimizu, Yusuke; Osanai, Chie; Yoshizawa, Atsushi

2011-02-15

172

Advances in the Fluorocarbon Process for Decontamination of Nuclear Facility off-Gas.  

National Technical Information Service (NTIS)

A selective adsorption process using R-12 was developed for removing noble gas fission products, exp 14 C, etc., from gaseous wastes of nuclear facilities. Its reliability has been proven by 10 years, operation of a 3-column process at ORGDP. A third gene...

B. E. Kanak

1979-01-01

173

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

NASA Astrophysics Data System (ADS)

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.

Han, Yousoo

174

Lukechangite-(Ce), a new rare-earth-fluorocarbonate mineral from Mont Saint-Hilaire, Quebec  

Microsoft Academic Search

Lukechangite-(Ce), ideally Na3Ce2(CO3)4F, is a new mineral from Mont Saint-Hilaire, Quebec. It occurs as tabular, short prismatic, and barrel-shaped crystals up to 1 mm. It is colorless to pale beige with a white streak and a vitreous, or somewhat pearly on {0001}, luster. Associated minerals include microcline, analcime, sodalite, aegirine, serandite, eu- dialyte, catapleiite, fluorite, petersenite-(Ce), siderite, astrophyllite, and albite.

JOEL D. GRICE; GEORGE Y. CHAO

175

Galvanic cell having a saturated fluorocarbon plasma-treated sealing gasket  

SciTech Connect

Galvanic cells employing compressible gaskets having at least a portion of the sealing areas of such gaskets coated with plasma deposited fluorine atoms demonstrate increased resistance to electrolyte leakage.

Yasuda, H.; van Lier, J. A.

1985-02-26

176

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

NASA Astrophysics Data System (ADS)

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

177

Multi-Dimensional Simulations of Fluorocarbon Plasmas with Ion Energy Resolved Surface Reaction Rates  

NASA Astrophysics Data System (ADS)

The commercial CFD-ACE+ software has been extended to account for ion energy dependent surface reactions. The ion energy distribution function and the mean ion energy at a biased wafer were obtained using the Riley sheath model extended by the NASA group (Bose et al., J. Appl. Phys. v.87, 7176(2000)). The plasma chemistry model (by P. Ho et al., SAND2001-1292) consisting of 132-step gas-phase reactions and 55-step ion energy dependent surface reactions, was implemented to simulate the C2F6 plasma etching of silicon dioxide in an Inductively Coupled Plasma. Validation studies have been performed against the experimental data by Anderson et al. of UNM for a lab-scale GEC reactor. For a wide range of operating conditions (pressure: 5-25 mTorr; plasma power: 205-495 Watts; bias power: 22-148 Watts), the average etch rate calculated by CFD-ACE+ 2-D simulations agrees very well with those by 0-D AURORA predictions and the experimental data. The CFD-ACE+ simulations allow one to study the radial uniformity of the etch rate depending on discharge conditions.

Zhou, Ning; Kolobov, Vladimir; Kudriavtsev, Vladimir

2001-10-01

178

Stabilization of Ba2YCu3O7-? by Surface Coating with Plasma Polymerized Fluorocarbon Film  

NASA Astrophysics Data System (ADS)

High-Tc superconducting Ba2YCu3O7-? pellets were coated with polyfluorocarbon thin films prepared by plasma polymerization of tetrafluoroethene (C2F4). The polymer-coated Ba2YCu3O7-? preserved its high-Tc superconductivity even after it had been kept standing in water at 60°C, whereas the superconductivity of noncoated pellets was completely destroyed under the same condition. The high hydrophobicity of the film originated from high fluorine content is considered to be primarily responsible for the protection of the superconductor from chemical deterioration by preventing the hydrolysis at the surface.

Sato, Kota; Omae, Shinji; Kojima, Kuniharu; Hashimoto, Takuya; Koinuma, Hideomi

1988-11-01

179

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

SciTech Connect

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

Bates, R. [Dept. of Physics and Astronomy, Univ. of Glasgow, G12 8QQ (United Kingdom); Battistin, M. [CERN, 1211 Geneva 23 (Switzerland); Berry, S.; Bitadze, A. [Dept. of Physics and Astronomy, Univ. of Glasgow, G12 8QQ (United Kingdom); Bonneau, P. [CERN, 1211 Geneva 23 (Switzerland); Bousson, N. [Centre de Physique des Particules de Marseille, 163 Avenue de Luminy, 13288 Marseille Cedex 09 (France); Boyd, G. [Dept. of Physics and Astronomy, Univ. of Oklahoma, Norman, OK 73019 (United States); Botelho-Direito, J.; DiGirolamo, B. [CERN, 1211 Geneva 23 (Switzerland); Doubek, M. [Czech Technical Univ., Technicka 4, 166 07 Prague 6 (Czech Republic); Egorov, K. [Physics Dept., Indiana Univ., Bloomington, IN 47405 (United States); Godlewski, J. [CERN, 1211 Geneva 23 (Switzerland); Hallewell, G. [Centre de Physique des Particules de Marseille, 163 Avenue de Luminy, 13288 Marseille Cedex 09 (France); Katunin, S. [B.P. Konstantinov Petersburg Nuclear Physics Inst. PNPI, 188300 St. Petersburg (Russian Federation); Mathieu, M.; McMahon, S. [Rutherford Appelton Laboratory - Science and Technology Facilities Council, Chilton, Didcot OX11 OQX (United Kingdom); Nagai, K. [Graduate School of Pure and Applied Sciences, Univ. of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Perez-Rodriguez, E. [CERN, 1211 Geneva 23 (Switzerland); Rozanov, A. [Centre de Physique des Particules de Marseille, 163 Avenue de Luminy, 13288 Marseille Cedex 09 (France); Vacek, V.; Vitek, M. [Czech Technical Univ., Technicka 4, 166 07 Prague 6 (Czech Republic)

2011-07-01

180

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

NASA Astrophysics Data System (ADS)

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

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

2003-09-01

181

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

EPA Science Inventory

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

182

Synthesis and Biological Screening of Novel Hybrid Fluorocarbon Hydrocarbon Compounds for Use as Artificial Blood Substitutes.  

National Technical Information Service (NTIS)

The goal of this project is to prepare a series of hybrid fluorochemicals of general structure R(f)1 R(f)2 R(f)3CR4, where the R(f)i's are saturated fluoroalkyl groups of formula C(n)F(2n+1), and R4 is an alkyl group C(n)H(2n+1) or related moity containin...

J. Moacanin K. Scherer A. Toronto D. Lawson T. Terranova

1978-01-01

183

New Fluorocarbon Elastomers for Seals for Geothermal and Other Aggressive Environments. Final Report.  

National Technical Information Service (NTIS)

Saturated ethyllenic elastomers having a range of methyl group substitution, and a range of partial fluorine substitution were screened. Elastomers based on vinylidene fluoride hexafluoropropylene (VDFHFP) and those based on tetrafluoroethylenepropylene (...

R. J. Lagow

1982-01-01

184

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

Microsoft Academic Search

Saturated ethyllenic elastomers having a range of methyl group substitution, and a range of partial fluorine substitution were screened. Elastomers based on vinylidene fluoride hexafluoropropylene (VDFHFP) and those based on tetrafluoroethylenepropylene (TFEP) (alternating) were successfully cross-linked by electron-beam radiation and fluorinated to yield elastomeric products, but those based on ethylene-propylene-diene (EPDM) elastomer became brittle after fluorination. The best products were

Lagow

1982-01-01

185

New fluorocarbon elastomers for seals for geothermal and other aggressive environments  

SciTech Connect

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.

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

1982-10-08

186

Fluorocarbon liner protected with chemical resistant masonry solves tough corrosion problem  

SciTech Connect

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

Heffner, D. [Electro Chemical Engineering and Manufacturing Inc., Emmaus, PA (United States)

1997-02-01

187

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

Microsoft Academic Search

Altering and controlling the properties of solid surfaces in aqueous or other liquid phase environments has been a sought after objective for decades. With the discovery of chemisorbed self-assembled monolayers, this dream has become a reality. Oxide and metal surfaces can now be readily coated with an array of commercially available products to produce a desired fnctionality. The presence of

Adam Justin Hopkins

2010-01-01

188

Equilibrium and Dynamic Surface Tension Properties of Aqueous Solutions of Sulfonated Cationic?Nonionic Fluorocarbon Surfactants  

Microsoft Academic Search

The equilibrium and dynamic surface tension properties in aqueous solutions of nonionic and cationic fluorinated surfactants bearing a sulfonated group are reported. Both surfactants show low critical micellar concentration and very low equilibrium surface tension values, but the cationic surfactant is more effective at decreasing surface tension, which is attributed to a small surface area per molecule. In dynamic surface

Hironobu Kunieda

2005-01-01

189

Microelectronic cooling by enhanced pool boiling of a dielectric fluorocarbon liquid  

Microsoft Academic Search

An experimental study of boiling heat transfer from a simulated microelectronic component immersed in a stagnant pool of the dielectric Fluorinert (FC-72) is presented. Various enhancement surfaces were attached to an electrically heated copper calorimeter bar having a vertically oriented heat transfer surface area of 12.7 à 12.7 mm². A number of enhancement schemes aimed at a reduction of the

T. M. Anderson; I. Mudawar

1989-01-01

190

Microelectronic cooling by enhanced pool boiling of a dielectric fluorocarbon liquid  

SciTech Connect

An experimental study of boiling heat transfer from a simulated microelectronic component immersed in a stagnant pool of the dielectric Fluorinert (FC-72) is presented. Various enhancement surfaces were attached to an electrically heated copper calorimeter bar having a vertically oriented heat transfer surface area of 12.7 {times} 12.7 mm{sup 2}. A number of enhancement schemes aimed at a reduction of the incipience temperature overshoot were tested, employing various arrangement of fins, studs, grooves, and vapor-trapping cavities. Atmospheric pressure testing revealed a variation in the magnitude of boiling curve incipience temperature excursion as a function of both macro- and microcharacterization of the surface geometry and initial conditions (pressure and temperature history) prior to boiling. Increased incipience temperatures accompanied prolonged periods of nonboiling. It is assumed that this is due to vapor embryos within surface cavities collapsing to smaller radii. Large artificially created cavities (0.3 mm diameter) were found incapable of maintaining a stable vapor embryo for time periods greater than 10 min. In comparison to flat surfaces, low-profile surface geometries having a structure scale of the order of one bubble departure diameter resulted in significant enhancement of nucleate boiling while drilled surfaces had minimal effectiveness. Surface finish and artificial cavities had no effect on CHF, but levels of critical heat flux computed on base area were strongly dependent on macrogeometry, due in part to increased surface area.

Anderson, T.M.; Mudawar, I. (Purdue Univ., West Lafayette, IN (United States))

1989-08-01

191

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

PubMed

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. PMID:18200930

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

2007-12-01

192

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

Microsoft Academic Search

Most complications of keratoprosthesis (KPro) occur at the tissue-to-implant interface. The ideal prosthesis would eliminate this interface by having the tissue actually grown into the support material forming the haptic. We present a 2-year clinical human study of a novel biocolonizable KPro on 24 eyes of 24 patients. To promote tissue stability, a 9 mm (Phi) skirt made of a

Jean-Marc Legeais; Gilles Renard; Jean-Marie Parel; Michelle Savoldelli; Yves Pouliquen

1994-01-01

193

Surface characterization of plasma deposited nano-structured fluorocarbon coatings for promoting in vitro cell growth  

Microsoft Academic Search

Nano-structured “teflon-like” coatings characterized by highly-fluorinated, random, ribbon-shaped, micrometers-long structures were deposited on polyethylenetherephtalate (PET) substrates by plasma enhanced-chemical vapour deposition (PE-CVD) using modulated radiofrequency (RF, 13.56MHz) glow discharges fed with C2F4 in modulated discharge (MD) and continuous wave (CW) regimes. Surfaces obtained in this way featured identical chemical composition and different roughness in the nanometric scale. Water contact angle

G. S. Senesi; E. D’Aloia; R. Gristina; P. Favia; R. d’Agostino

2007-01-01

194

Oil-fluorocarbon direct contact heat exchanger for low temperature power generation  

Microsoft Academic Search

In order to demonstrate the feasibility of power generation from medium and low temperature waste heat, geothermal heat, etc, a direct contact heat exchanger was developed. This new heat exchanger is especially excellent in its economies and heat exchange characteristics. To obtain design data for actual applications, a full-scale test was conducted to clarify problems encountered in the basic experiments.

S. Sakaguchi; U. Kuroda

1983-01-01

195

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

Code of Federal Regulations, 2010 CFR

...1Characterization a. Gas Chromatography b. Boiling point and boiling point range 4.1.2Contaminants a. Water b...Since R-11, R-113, and R-123 have normal boiling points at or above room temperature,...

2010-07-01

196

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

Code of Federal Regulations, 2013 CFR

...Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) PROTECTION OF STRATOSPHERIC OZONE Recycling and Emissions Reduction Pt. 82, Subpt. F, App. A Appendix A to Subpart F of Part 82âSpecifications for...

2013-07-01

197

Fluorine-doped SiO 2 and fluorocarbon low- k dielectrics investigated by SIMS  

Microsoft Academic Search

In this work, we present secondary ion mass spectrometry (SIMS) investigations of the incorporation of fluorine into thin SiO2 films adapted as low-k dielectrics in the metal-oxide-semiconductor (MOS) devices.The insulating SiOF oxides with the thickness ranging from 1 up to 15nm have been prepared by plasma-enhanced chemical vapor deposition (PECVD) and\\/or by reactive ion etching (RIE) methods on ?100? oriented

M. Cwil; M. Kalisz; P. Konarski

2008-01-01

198

Investigation of fluorocarbon blowing agents in insulating polymer foams by 19F NMR imaging  

Microsoft Academic Search

Currently, there is no reliable and readily accessible technique with which the distribution and diffusion of blowing agents in rigid insulating foams can be detected and monitored. In this paper, we demonstrate that 19F NMR microscopic imaging together with 19F solid-state MAS NMR spectroscopy is ideally suited for such measurements and yield quantitatively reliable information that will be critical to

C. A. Fyfe; Z. Mei; H. Grondey

1996-01-01

199

Characterization of Etching of Silicon Dioxide and Photoresist in a Fluorocarbon Plasma.  

National Technical Information Service (NTIS)

Reactive ion etching of silicon dioxide and positive photoresist in CHF3-C2F6-O2-He plasma in a parallel-plate etcher is studied using the response surface experimental design procedure. The experimental results are reproducible within 5%. Analytical expr...

P. C. Karulkar M. A. Wirzbicki

1988-01-01

200

Mitigation of accumulated electric charge by deposited fluorocarbon film during SiO2 etching  

Microsoft Academic Search

SiO2 contact-hole etching with a high-aspect ratio is a key process in fabricating ultra-large scale integrated devices. However, charge accumulation in contact holes during plasma etching causes serious problems, such as charge-build-up damage, etching-stop, and microloading effects. Therefore, understanding the mechanism behind this electric charge accumulation and controlling the plasma etching processes would be very important to achieve the next-generation

Tadashi Shimmura; Yuya Suzuki; Sinnosuke Soda; Seiji Samukawa; Mitsumasa Koyanagi; Kazuhiro Hane

2004-01-01

201

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...

202

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

SciTech Connect

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

Lagow, R.J.

1982-12-01

203

Evaluating the robustness of top coatings comprising plasma-deposited fluorocarbons in electrowetting systems  

Microsoft Academic Search

Thin dielectric stacks comprising a main insulating layer and a hydrophobic top coating are commonly used in low voltage electrowetting systems. However, in most cases, thin dielectrics fail to endure persistent electrowetting testing at high voltages, namely beyond the saturation onset, as electrolysis indicates dielectric failure. Careful sample inspection via optical microscopy revealed possible local delamination of the top coating

Dimitrios P. Papageorgiou; Elias P. Koumoulos; Costas A. Charitidis; Andreas G. Boudouvis; Athanasios G. Papathanasiou

2011-01-01

204

Evaluating the Robustness of Top Coatings Comprising Plasma-Deposited Fluorocarbons in Electrowetting Systems  

Microsoft Academic Search

Thin dielectric stacks comprising a main insulating layer and a hydrophobic top coating are commonly used in low voltage electrowetting systems. However, in most cases, thin dielectrics fail to endure persistent electrowetting testing at high voltages, namely beyond the saturation onset, as electrolysis indicates dielectric failure. Careful sample inspection via optical microscopy revealed possible local delamination of the top coating

Dimitrios P. Papageorgiou; Elias P. Koumoulos; Costas A. Charitidis; Andreas G. Boudouvis; Athanasios G. Papathanasiou

2012-01-01

205

Explosive Reactions Produced by Spark Ignition on Mixtures of Fluorine with Fluorocarbons and Chlorofluorocarbons.  

National Technical Information Service (NTIS)

Conditions exist for an explosive reaction whenever a mixture is formed from two or more gases which are thermodynamically unstable toward their gaseous reaction products. Reaction under these conditions may be triggered by a localized electric discharge ...

H. A. Bernhardt C. F. Hale E. J. Barber

1968-01-01

206

Explosive reactions produced by spark ignition on mixtures of fluorine with fluorocarbons and chlorofluorocarbons. [Trichloroheptafluorobutane; perfluorodimethylcyclohexane  

Microsoft Academic Search

Conditions exist for an explosive reaction whenever a mixture is formed from two or more gases which are thermodynamically unstable toward their gaseous reaction products. Reaction under these conditions may be triggered by a localized electric discharge or thermally by elevation of the gas temperature above the adiabatic combustion temperature of the gas mixture. Once initiated, the flame propagates in

H. A. Bernhardt; C. F. Hale; E. J. Barber

1968-01-01

207

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

ERIC Educational Resources Information Center

|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)|

McCulloch, Archie

1994-01-01

208

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

National Technical Information Service (NTIS)

The fact that the viscosity of acetone solutions of cellulose diacetate (CDA) DATs can be reduced by the addition of small quantities of water has been known for a long time. It is given practical application in the production of acetone fiber. An analogo...

L. A. Shits N. Y. Kal'nova

1985-01-01

209

Fluorocarbon-based single-layer resist for 157-nm lithography  

NASA Astrophysics Data System (ADS)

We have designed and synthesized a number of unique polymer systems composed of acrylate and styrene even though it had moderate transparency. Our first model of 157nm photoresist was based on a (alpha) trifluoromethylacrylate and styrene bearing a pendent hexafluoroisopropanol with pentafluoroisopropyl t-butyl carbonate (PFITBC) as the transparent enhancer and acid labile compound. PFITBC was obtained from perfluorinated enolate with di-t-butyl carbonate with high yield. All of the absorbance of our system ranged over 3.0~3.4micrometers -1 for base resin, which corresponded to a resist thickness of 110~125 nm at the optical density of 0.4. We have formulated several resists based on these polymers and these formulations have shown high resolution and contrast at 248 nm. We were able to obtain 240nm 1:1 image when exposed at 248 nm by a Nikon stepper with 0.45NA. To overcome the weak etch resistance with thin thickness film, we investigated the vapor phase silylation treatment (SILYAL) in which the treated pattern was more persistent against the O2 plasma and turned to smoother surface. DMSMDA with Bi(DMA)MS of 30-40 wt% showed not only good control resist flow but also the improvement of line-edge roughness. Our results suggested that a facile approach to fluorine incorporated resin with SILYAL process can accelerate the 157nm lithography.

Song, Ki-Yong; Yoon, Kwang-Sub; Choi, Sang-Jun; Woo, Sang-Gyun; Han, Woo-Sung; Lee-DUPLICATE RECORD-DO NOT US, Jae-Jun; Lee, Sang-Kyun; Noh, Chang-Ho; Honda, Kenji

2002-07-01

210

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

SciTech Connect

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

Orkin, V.L.; Khamaganov, V.G.; Guschin, A.G.; Kasimovskaya, E.E.; Larin, I.K. [Institut Energeticheskiskh Problem Khimicheskoi Fiziki, Moscow (Russian Federation)

1993-04-01

211

Spectral separation of gaseous fluorocarbon mixtures and measurement of diffusion constants by 19F gas phase DOSY NMR  

NASA Astrophysics Data System (ADS)

Diffusion-ordered (DOSY) NMR techniques have for the first time been applied to the spectral separation of mixtures of fluorinated gases by diffusion rates. A mixture of linear perfluoroalkanes from methane to hexane was readily separated at 25 °C in an ordinary experimental setup with standard DOSY pulse sequences. Partial separation of variously fluorinated ethanes was also achieved. The constants of self-diffusion of a set of pure perfluoroalkanes were obtained at pressures from 0.25 to 1.34 atm and temperatures from 20 to 122 °C. Under all conditions there was agreement within 20% of experimental self-diffusion constant D and values calculated by the semiempirical Fuller method.

Marchione, Alexander A.; McCord, Elizabeth F.

2009-11-01

212

Characterization of film failures by bismuth electrodeposition—Application to thin deformed fluorocarbon films for stent applications  

Microsoft Academic Search

A new approach for the detection and visualization of nano-scaled film defects, such as fissures and holes is described. The procedure is based on a selective electrochemical deposition of bismuth onto uncovered parts of stainless steel substrates due to film cracking after deformation. Cyclic voltammetry experiments enabled the identification of the bismuth redox signals, necessary for the subsequent potentiostatic electrodeposition.

Servaas Holvoet; Paula Horny; Stephane Turgeon; Pascale Chevallier; Jean-Jacques Pireaux; Diego Mantovani

2010-01-01

213

Study on the stability of plasma-polymerized fluorocarbon ultra-thin coatings on stainless steel in water  

Microsoft Academic Search

Metallic stents are thin wire mesh tubes implanted in partially blocked arteries to prevent the obstruction of blood flow and to act as internal scaffolding. Mainly made of 316L stainless steel, they are prone to localized corrosion attack in long-term applications which in turn causes the release of potentially toxic ions such as chromium and nickel. To improve the long-term

M. Touzin; P. Chevallier; F. Lewis; S. Turgeon; S. Holvoet; G. Laroche; D. Mantovani

2008-01-01

214

Comparative study of hydrocarbon, fluorocarbon, and aromatic bonded RP-HPLC stationary phases by linear solvation energy relationships.  

PubMed

The retention properties of eight alkyl, aromatic, and fluorinated reversed-phase high-performance liquid chromatography bonded phases were characterized through the use of linear solvation energy relationships (LSERs). The stationary phases were investigated in a series of methanol/water mobile phases. LSER results show that solute molecular size and hydrogen bond acceptor basicity under all conditions are the two dominant retention controlling factors and that these two factors are linearly correlated when either different stationary phases at a fixed mobile-phase composition or different mobile-phase compositions at a fixed stationary phase are considered. The large variation in the dependence of retention on solute molecular volume as only the stationary phase is changed indicates that the dispersive interactions between nonpolar solutes and the stationary phase are quite significant relative to the energy of the mobile-phase cavity formation process. PCA results indicate that one PCA factor is required to explain the data when stationary phases of the same chemical nature (alkyl, aromatic, and fluoroalkyl phases) are individually considered. However, three PCA factors are not quite sufficient to explain the whole data set for the three classes of stationary phases. Despite this, the average standard deviation obtained by the use of these principal component factors are significantly smaller than the average standard deviation obtained by the LSER approach. In addition, selectivities predicted through the LSER equation are not in complete agreement with experimental results. These results show that the LSER model does not properly account for all molecular interactions involved in RP-HPLC. The failure could reside in the V2 solute parameter used to account for both dispersive and cohesive interactions since "shape selectivity" predictions for a pair of structural isomers are very bad. PMID:10464478

Reta, M; Carr, P W; Sadek, P C; Rutan, S C

1999-08-15

215

Mechanism for the selective etch of silicon dioxide in a high-density, low-pressure, inductively coupled fluorocarbon plasma  

Microsoft Academic Search

A novel, end launched, m=0 mode helicon wave was developed through the application of an axial magnetic field to a flat, spiral coil, inductively coupled plasma source. The rf magnetic field structure in the plasma was determined with induction probes and shown to match the theory of an m=0 helicon wave. Helicon wave power deposition, determined from axial damping of

Mark Justin Sowa

1999-01-01

216

TARGET: thermal accelerated reliability go-no-go environmental testing dynamic board thermal shock using a single liquid fluorocarbon bath  

Microsoft Academic Search

TARGET, a novel method of accelerated thermal stress for board testing, is described. This method utilizes Fluorinert as the medium for rapid thermal energy transfer. Possible applications include environments for STRIFE testing and board debug. One of the most promising applications is in-line environmental stress screening (ESS). Boards receive a thorough temperature stress screen in the time taken for conventional

Bradford P. Beaton

1991-01-01

217

The Ionization Potential of the CF3 Radical and Some Fluorocarbon Bond Energies Obtained by Electron Impact  

Microsoft Academic Search

1in the two spectra would, however, suggest that the poly­ crystalline mass behaves as a disordered crystal. In the third paragraph Sirkar states that changes in the con­ dition of the crystal which produce changes in the Raman spec­ trum fail to produce any change in the Laue pattern. The changes to which Sirkar refers are very doubtful; the main

Vernon H. Dibeler; Robert M. Reese; Fred L. Mohler

1952-01-01

218

Halogenated Hydrocarbons and Drug Metabolism: The Effect of Fluorocarbons on Hexobarbital Sleeping and Zoxazolamine Paralysis Times in Mice.  

National Technical Information Service (NTIS)

A screening program has been initiated for the purpose of exploring the possibility that the inhalation exposure of rodents to selected halogenated hydrocarbons may affect enzymes of the hepatic smooth endoplasmic reticulum, the so-called microsomal drug-...

E. W. Van Stee J. P. F. Murphy K. C. Back

1971-01-01

219

Investigation of ion transportation in high-aspect-ratio holes from fluorocarbon plasma for SiO 2 etching  

Microsoft Academic Search

We investigated the behavior of ions in deep contact holes under actual dry etching conditions by comparing results between experimental and numerical simulations. In the experiments, we directly measured the ions that penetrated a real-contact-hole-sized (0.2 ?mø) micro-capillary plate, which was a membrane with many throughholes fabricated on a Si wafer with a structure customized to simulate the actual electric

Shuichi Noda; Nobuo Ozawa; Takashi Kinoshita; Hideo Tsuboi; Kenji Kawashima; Yukinobu Hikosaka; Keizo Kinoshita; Makoto Sekine

2000-01-01

220

Interim Proposal for Molecular Beam Studies of Surfactants in Sulfuric Acid Aerosols: Comparisons Between Hydrocarbon and Fluorocarbon Alcohols.  

National Technical Information Service (NTIS)

Heterogeneous reactions of gas phase molecules with aqueous sulfuric acid aerosols play a significant role in the destruction of ozone in the stratosphere. These processes include the acid-catalyzed reactions of HCI and HBr with CIONO2 (BrONO2) and HOCI (...

G. M. Nathanson

2003-01-01

221

The Preparation of Monomers for the Synthesis of Fluorocarbon Polymers by the Oxidation of Fluoro-olefins  

NASA Astrophysics Data System (ADS)

The oxidation reactions of fluoro-olefins are examined: the conditions under which they take place, the characteristic features of the mechanism, and the composition and structure of the products formed. Attention is concentrated on the oxidation reactions of industrial perfluoro-olefins, namely tetrafluoro-ethylene and hexafluoropropene, and also on the methods of synthesis of the most important products of the oxidation of fluoro-olefins — fluorocarbonepoxides and oligomeric perfluoropolyesters. The characteristics of the physicochemical properties and the main applications of oxygen-containing products of the oxidation of fluoro-olefins are discussed. The bibliography includes 154 references.

Sokolov, L. F.; Valov, P. I.; Sokolov, Sergey V.

1984-07-01

222

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

PubMed

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

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

2012-07-27

223

Characterization of polymer formation during SiO2 etching with different fluorocarbon gases (CHF3, CF4, C4F8)  

Microsoft Academic Search

In this paper, the polymer composition generated by three different combinations of gas chemistries for oxide etch are studied and the effects of different O2 plasma strip duration on polymer removal are also presented. The etch chemistries used were CHF3\\/CF4, CO\\/CF4\\/CHF3 and C4F8\\/CO\\/CHF3 chemistry. From the x-ray photoelectron spectroscopy (XPS) C 1s spectra, five distinct peaks are identified which correspond

Sang Y. Loong; H. K. Lee; Lap H. Chan; M. S. Zhou; F. C. Loh; Kuang L. Tan

1997-01-01

224

Dimerisation of butadiene catalyzed by nickel–tris[(1 H,1 H,2 H,2 H-perfluorodecyl)phenyl]phosphites complexes in fluorocarbon–hydrocarbon biphasic medium  

Microsoft Academic Search

Cyclodimerisation of butadiene into 1,5-cyclooctadiene can be efficiently performed under fluorous–organic biphasic conditions using Ni(COD)2 as catalytic precursor and triarylphosphites bearing long perfluorinated alkyl chain separated from the aromatic ring by an ethylene spacer group as ligand. As found earlier under homogeneous conditions, phosphites with ortho substituent are much more active than their para-substituted counterpart and a remarkable enhancement of

Renata Matusiak; Yves Castanet; André Mortreux

2004-01-01

225

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

PubMed Central

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

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

2011-01-01

226

Tribological Effects of Brush Scrubbing in Post Chemical Mechanical Planarization Cleaning on Electrical Characteristics in Novel Non-porous Low-k Dielectric Fluorocarbon on Cu Interconnects  

Microsoft Academic Search

Damage reduction during planarization is strongly required to avoid scratch generation and the variation in the electrical properties of low-k dielectrics leading to yield loss in an integrated circuit after the implementation of an ultralow-k dielectric in Cu damascene interconnects. An optimum process condition to reduce damage on brush scrubbing in post-chemical--mechanical-planarization (post-CMP) cleaning was proposed for advanced nonporous organic

Xun Gu; Takenao Nemoto; Yugo Tomita; Akinobu Teramoto; Shigetoshi Sugawa; Tadahiro Ohmi

2011-01-01

227

Crystal structures and phase-transition dynamics of cobaltocenium salts with bis(perfluoroalkylsulfonyl)amide anions: remarkable odd-even effect of the fluorocarbon chains in the anion.  

PubMed

Crystal structures and thermal properties of cobaltocenium salts with bis(perfluoroalkylsulfonyl)amide (C(n)F2(n+1)SO2)2N anions [n = 0 (1), 1 (1?a), 2 (1?b), 3 (1?c), and 4 (1?d)] and the 1,1,2,2,3,3-hexafluoropropane-1,3-disulfonylamide anion (2) were investigated. In these solids, the cations are surrounded by four anions around their C5 axis, and stacking of these local structures forms two kinds of assembled structures. In the salts with even n (1, 1?b, and 1?d), the cation and anion are arranged alternately to form mixed-stack columns in the crystal. In contrast, in the salts with odd n (1?a and 1?c), the cations and anions independently form segregated-stack columns. An odd-even effect was also observed in the sum of the phase-change entropies from crystal to melt. All of the salts exhibited phase transitions in the solid state. The phase transitions to the lowest-temperature phase in 1, 1?a, and 2 are accompanied by order-disorder of the anions and symmetry lowering of the space group, which results in the formation of an ion pair. Solid-state (13)C?NMR measurements on 1?a and 1?b revealed enhanced molecular motions of the cation in the higher-temperature phases. PMID:23576337

Mochida, Tomoyuki; Funasako, Yusuke; Inagaki, Takashi; Li, Meng-Jiao; Asahara, Kotaro; Kuwahara, Daisuke

2013-04-09

228

Method of Bonding Diamonds in a Matrix and Articles Thus Produced.  

National Technical Information Service (NTIS)

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 resi...

G. W. Taylor

1981-01-01

229

Chemical Technology and Economics in Environmental Perspectives. Task . Investigation of Alternatives for Selected Aerosol Propellants and Related Applications of Chlorofluorocarbons.  

National Technical Information Service (NTIS)

Several aerosol propellant and related applications of fluorocarbons were examined to identify existing and technologically feasible alternatives. Associated cost factors were also considered. Interested parties brought these fluorocarbon applications to ...

T. W. Lapp G. L. Kelso L. Breed H. Gadberry T. Milne

1977-01-01

230

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

Code of Federal Regulations, 2010 CFR

...1,1-trichloroethane, carbon tetrachloride, chlorinated fluorocarbons...dichloromethane, trichloromethane, carbon tetrachloride, chloroethylene...Dichloromethane; Trichloromethane; Carbon tetrachloride;...

2010-07-01

231

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

Code of Federal Regulations, 2010 CFR

...1,1-trichloroethane, carbon tetrachloride, chlorinated fluorocarbons...dichloromethane, trichloromethane, carbon tetrachloride, chloroethylene...Dichloromethane; Trichloromethane; Carbon tetrachloride;...

2009-07-01

232

Environmentally harmonized plasma etching processes of amorphous silicon and tungsten  

Microsoft Academic Search

A novel etching process of a-Si and W for cleaning the CVD chamber employing ECR O2 plasma with injecting fluorocarbon radicals generated from a fluorocarbon radical source was developed for replacing green house gases such as SF6 gas and PFC gases. We proposed a new radical control method where the generated high order fluorocarbon radicals introduced into the plasma reactor

M. Hori; K. Fujita; S. Kobayashi; M. Ito; T. Goto

2000-01-01

233

Silicon Oxide Selective Etching and Chamber Cleaning Processes for Preventing Global Warming  

Microsoft Academic Search

Fluorocarbon gases and SF6 gas are used in dry etching processes for the thin film patterning and chamber cleaning after film depositions. The use of these gases, however, will be restricted because of environmental problem, namely global warming. In this study, we have developed a novel fluorocarbon gas source without using fluorocarbon feed gases for preventing global warming, where polytetrafluoroethylene

Kazushi Fujita; Shigeto Kobayashi; Masafumi Ito; Masaru Hori; Toshio Goto

1998-01-01

234

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  

Microsoft Academic Search

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

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

2002-01-01

235

Recovery of purified helium or hydrogen from gas mixtures  

DOEpatents

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)

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

1974-01-15

236

Separation of Fluorinated Amino Acids and Oligopeptides from their Non-fluorinated Counterparts using High-performance Liquid Chromatography  

PubMed Central

Chromatographic conditions for the separation of fluorinated amino acids and oligopeptides from their non-fluorinated counterparts were explored. The separation of six pairs of analytes, including both aromatic and aliphatic fluorocarbons, was investigated at various temperatures using both hydrocarbon and fluorocarbon columns and eluents. Our results show that when hydrocarbon eluents are used, fluorocarbon column provides better separation of fluorinated amino acids or oligopeptides from their non-fluorinated counterparts; when fluorocarbon eluents are used, hydrocarbon column provides better separation of fluorinated amino acids or oligopeptides from their non-fluorinated counterparts. These chromatographic behaviors reflect the fluorophilicity possessed by fluorinated amino acids and oligopeptides.

Xiao, Nu; Yu, Y. Bruce

2010-01-01

237

Computing all the azeotropes in refrigerant mixtures through equations of state  

Microsoft Academic Search

Azeotropic mixtures of fluorocarbon (FC) and hydro fluorocarbon (HFC) with hydrocarbons are gaining popularity as drop-in substitutes for CFCs and HCFCs. A method to compute all the azeotropes in a refrigerant mixture through the equation of state approach is described. The method allows prediction of all the azeotropes in a refrigerant mixture and is in close agreement with the experimental

Naveed Aslam; Aydin K. Sunol

2004-01-01

238

Chemical technology and economics in environmental perspectives. Investigation of alternatives for selected aerosol propellants and related applications of chlorofluorocarbons. Final report  

Microsoft Academic Search

Several aerosol propellant and related applications of fluorocarbons were examined to identify existing and technologically feasible alternatives. Associated cost factors were also considered. Interested parties brought these fluorocarbon applications to the attention of an interagency work group (EPA, FDA, and CPSC) as being possible 'essential uses' of these substances. The applications examined under the task were: flying insect insecticides, other

T. W. Lapp; G. L. Kelso; L. Breed; H. Gadberry; T. Milne

1977-01-01

239

Efficiencies of transcritical CO 2 cycles with and without an expansion turbine  

Microsoft Academic Search

With the discovery that fluorocarbons may have a profoundly detrimental effect on the earth's atmosphere, it has become necessary to find a suitable replacement for a fluorocarbon-based refrigeration cycle. Such a replacement must perform comparably to current refrigerants, be economically feasible, and significantly reduce the possibility of a negative environmental impact compared with current refrigerants. A review of the literature

Douglas M. Robinson; Eckhard A. Groll

1998-01-01

240

Method for removing uranium-containing deposits in uranium hexafluoride processing equipment  

SciTech Connect

This invention pertains to a method for removing deposits of uranium compounds in uranium hexafluoride handling equipment. A fluorocarbon containing bromine is internally injected into the handling equipment at or below ambient pressure and this brominating agent removes uranium compounds which have been formed therein. A fluoridating agent is also preferably used in conjunction with the fluorocarbon containing bromine.

Bacher, W.; Jacob, E.

1982-01-19

241

Method for removing uranium-containing deposits in uranium hexafluoride processing equipment  

Microsoft Academic Search

This invention pertains to a method for removing deposits of uranium compounds in uranium hexafluoride handling equipment. A fluorocarbon containing bromine is internally injected into the handling equipment at or below ambient pressure and this brominating agent removes uranium compounds which have been formed therein. A fluoridating agent is also preferably used in conjunction with the fluorocarbon containing bromine.

W. Bacher; E. Jacob

1982-01-01

242

Survival of Mammals Breathing Organic Liquids Equilibrated with Oxygen at Atmospheric Pressure  

Microsoft Academic Search

Because oxygen and carbon dioxide are very soluble in certain silicone oils and fluorocarbon liquids, these liquids will support respiration of mammals. Mice and cats respiring silicone oil die shortly after return to air breathing, while those breathing fluorocarbon survive for weeks. The respiration of mice is optimally supported by these organic liquids at about 20 degrees C. In cats,

Leland C. Clark Jr.; Frank Gollan

1966-01-01

243

Refrigeration and Air-Conditioning Technology Workshop  

Microsoft Academic Search

The Alternative Fluorocarbon Environmental Acceptability Study (AFEAS), a consortium of fluorocarbon manufacturers, and the U.S. Department of Energy (DOE) are collaborating on a project to evaluate the energy use and global warming impacts of CFC alternatives. The goal of this project is to identify technologies that could replace the use of CFC's in refrigeration, heating, and air-conditioning equipment; to evaluate

P. J. Lewis; D. M. Counce

1993-01-01

244

Method of bonding diamonds in a matrix and articles thus produced  

DOEpatents

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.

Taylor, G.W.

1981-01-27

245

Normothermic preservation of "multiple organ blocks" with a new perfluorooctyl bromide emulsion.  

PubMed

To evaluate the efficiency of fluorocarbon emulsions as oxygenating media for the normothermic preservation of organs (multiple organ blocks, MOB), a new perfluorooctyl bromide (perflubron) emulsion was compared with a mixture of modified Krebs solution and blood. The fluorocarbon emulsion used (90% w/v of fluorocarbon) contained a low amount of egg yolk phospholipid (EYP, 2% w/v) and was stabilized by a mixed fluorocarbon-hydrocarbon amphiphile C6F13C10H21 (F6H10). Blood of 4 rat MOBs was replaced with a 36% w/v fluorocarbon emulsion which has been complemented with albumin and electrolytes (EMOBs). 5 MOBs were perfused with a mixture of blood and albumin-containing Krebs solution (KBMOBs). Lactate, amylase and creatine kinase were lower (p < 0.05) at 60 and 120 min in EMOBs than in KBMOBs, PMID:7849957

Voiglio, E J; Zarif, L; Gorry, F; Krafft, M P; Margonari, J; Dubernard, J M; Riess, J G

1994-01-01

246

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

SciTech Connect

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.

Lagow, R.J.

1993-04-01

247

Synthesis of new high performance lubricants and solid lubricants  

SciTech Connect

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.

Lagow, R.J.

1993-04-01

248

40 CFR 414.40 - Applicability; description of the thermoplastic resins subcategory.  

Code of Federal Regulations, 2012 CFR

...Nitrate *Ethylene-Methacrylic Acid Copolymers *Ethylene-Vinyl Acetate Copolymers *Fatty Acid Resins *Fluorocarbon Polymers Nylon 11 Resin *Nylon 6-66 Copolymers *Nylon 6âNylon 11 Blends Nylon 6 Resin Nylon 612 Resin Nylon 66...

2012-07-01

249

Earth's Endangered Ozone  

ERIC Educational Resources Information Center

|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)|

Panofsky, Hans A.

1978-01-01

250

HYDRAULIC STUDIES AND CLEANING EVALUATIONS OF ULTRAVIOLET DISINFECTION UNITS  

EPA Science Inventory

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

251

Public hearings on protection of people and the environment. Foreign trip report, December 3--4, 1992.  

National Technical Information Service (NTIS)

The traveler, representing the AFEAS (Alternative Fluorocarbon, Environmental Acceptability Study)/DOE global warming project, participated as an invited expert in the public hearings held by the Enquete Commission of the German Bundestag to present a sum...

P. D. Fairchild

1992-01-01

252

Relaxation of Fluorine Nuclei by Collisions with Free Radicals.  

National Technical Information Service (NTIS)

Intermolecular nuclear relaxation during liquid-state collisions has been examined for 16 combinations of four free radicals and four fluorocarbons. The spectra of electron-induced scalar relaxation transistions are resolved into high- and low-frequency c...

E. H. Poindexter P. J. Caplan B. E. Wagner R. D. Bates

1974-01-01

253

49 CFR 173.115 - Class 2, Divisions 2.1, 2.2, and 2.3-Definitions.  

Code of Federal Regulations, 2011 CFR

...the service pressure is 12410 kPa (1800 psig). (j) Refrigerant gas or Dispersant gas. The terms Refrigerant gas and Dispersant gas apply to all nonpoisonous refrigerant gases; dispersant gases (fluorocarbons) listed in §...

2011-10-01

254

40 CFR 82.164 - Reclaimer certification.  

Code of Federal Regulations, 2012 CFR

...2004, all persons reclaiming used refrigerant for sale to a new owner, except...such person will: (a) Reprocess refrigerant to all of the specifications in Appendix...Specification for Fluorocarbons and Other Refrigerants ) that are applicable to that...

2012-07-01

255

49 CFR 173.115 - Class 2, Divisions 2.1, 2.2, and 2.3-Definitions.  

Code of Federal Regulations, 2012 CFR

...the service pressure is 12410 kPa (1800 psig). (j) Refrigerant gas or Dispersant gas. The terms Refrigerant gas and Dispersant gas apply to all nonpoisonous refrigerant gases; dispersant gases (fluorocarbons) listed in §...

2012-10-01

256

16 CFR Appendix A to Part 423 - Glossary of Standard Terms  

Code of Federal Regulations, 2013 CFR

...or out of doors. i. âLine dry in shadeââdry away from sun. j. âLine dry away from heatââdry away from heat...solvent (for example, petroleum, perchlorethylene, fluorocarbon) located in any commercial establishment. The process...

2013-01-01

257

Superhydrophobic lignocellulosic wood fiber/mineral networks.  

PubMed

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

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

2013-09-05

258

Cardiovascular disease and environmental exposure.  

PubMed Central

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.

Rosenman, K D

1979-01-01

259

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

EPA Science Inventory

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

260

Elastomer Compatibility Studies.  

National Technical Information Service (NTIS)

With the aim of a better understanding of a field problem concerning elastomer compatibility, work is carried out using a novel elastomeric (fluorocarbon) material of high temperatures, with three commercially available gas turbine lubricants. A study pro...

J. Vantilborg

1985-01-01

261

Seasonal Performance Evaluation Procedures for Domestic Electric Driven Heat Pumps and Air Conditioners.  

National Technical Information Service (NTIS)

Virtually all of the residential and commercial heat pumps available in today's market operates on the same fundamental principles as do that of the vapor compression cycle. Also, virtually all of these systems use fluorocarbon compounds as a working flui...

D. A. Didion

1988-01-01

262

Occurrence of a Double Azeotrope in the Binary System Hexafluorobenzene+Benzene  

Microsoft Academic Search

RECENTLY there has been much interest in the thermo-dynamic properties of binary mixtures of aromatic fluorocarbons and aromatic hydrocarbons. Experimental studies of the phase diagrams1,2, excess volumes3 and excess enthalpies4 of mixing can be interpreted by assuming that intermolecular complexing exists between the two components. This complexing is believed to result from charge-transfer interaction, with the fluorocarbon acting as the

W. J. Gaw; F. L. Swinton

1966-01-01

263

Volcanic gases in the April 1979 Soufriere eruption  

SciTech Connect

Six gas samples from the 17 April 1979 Soufriere eruption plume were analyzed for carbonyl sulfide, carbon disulfide, carbonmonoxide, carbon dioxide, methane, nitrous oxide, fluorocarbon-11, fluorocarbon-12, methyl chloroform, and carbon tetrachloride. Only carbon monoxide, carbon dioxide, carbonyl sulfide, and carbon disulfide were found to have increased mixing ratios as compared with those in clean tropospheric air, but the increases were not sufficient to contribute greatly to the global budgets of these four components. 10 references, 2 tables.

Cronn, D.R.; Nutmagul, W.

1982-06-04

264

Syntheses with perfluoroalkyl iodides. Part II. Addition to non-conjugated alkadienes; cyclization of 1,6-heptadiene, and of 4-substituted 1,6-heptadienoic compounds: bis-allyl ether, ethyl diallylmalonate, N, N?-diallylamine and N-substituted diallylamines; and additions to homologous exo- and endocyclic alkenes, and to bicyclic alkenes  

Microsoft Academic Search

Non-conjugated dienes, with an azonitrile initiator, add one or two RFI to provide RFRH “diblock” and RFRHRF “triblock” compounds with one, or two perfluoroalkyl groups, respectively. Those diblock products with long fluorocarbon and hydrocarbon segments furnish novel surfactants for fluorocarbon liquid systems, and are cell structure modifiers for biochemical applications. In the case of 1,6-heptadiene, the perfluoroalkyl radical adds first

Neal O. Brace

1999-01-01

265

Synthesis of fluorinated hyperbranched polymers capable as highly hydrophobic and oleophobic coating materials  

Microsoft Academic Search

A series of coating materials were prepared from two classes of hyperbranched polymers containing short fluorocarbon chains (HPEFs\\/HPUFs). The obtained hyperbranched polymers were characterized by FT-IR, 1H NMR, 13C NMR, 19F NMR, GPC and TG analyses. HPEFs\\/HPUFs exhibited very low surface free energies (13.67–24.49mJ\\/m2) which almost are independent of their internal backbone but dependent on the terminal fluorocarbon chains. Highly

Weiyi Tang; Yangen Huang; Weidong Meng; Feng-Ling Qing

2010-01-01

266

Miscibility of binary mixtures of highly fluorinated double-chain glycerophosphocholines and 1,2-dipalmitoylphosphatidylcholine (DPPC)  

Microsoft Academic Search

The miscibility of highly fluorinated glycerophosphocholines with conventional ones and among themselves has been studied by DSC. The least fluorinated DF4C11PC of the series displays restricted miscibility with DPPC. The binary systems formed from the mixed-chain fluorocarbon\\/hydrocarbon [F8E11][C16]OPC and the homogenous fluorocarbon DF8C11OPC or hydrocarbon DPPC, respectively, exhibit increased miscibility in both the gel and fluid phases, although both systems

Jean-Paul Rolland; Catherine Santaella; Bernard Monasse; Pierre Vierling

1997-01-01

267

Analysis and modeling of nucleate boiling in highly-wetting liquids  

Microsoft Academic Search

In recent years, the incessant drive towards higher heat flux and power density in nearly all categories of electronic equipment has turned attention to the use of dielectric liquids, such as the Fluoro-Fluorocarbons (Fluorinerts) and the Chloro-Fluorocarbons (Freons) for the thermal control of electronic components. Since these liquids, referred to as highly-wetting liquids, possess some unusual characteristic properties as compared

Tong

1989-01-01

268

[The effect of a fluorocarbon emulsion--an enzyme inducer of the cytochrome P-450-dependent monooxygenase system of the liver--on the acute toxicity of CCl4 and on the efficacy of the prophylactic use of antidotes in organophosphate pesticide poisoning].  

PubMed

The effect of intraperitoneal administration of perfluorocarbon emulsion, an inducer of cytochrome P-450-dependent monoxygenase system of the liver, on the resistance of rodents to the action of CCl4 and organophosphorus pesticides was studied. Perfluorocarbon emulsion potentiated CCl4 toxicity decreasing LD50 from 4.5 to 3.7 mg/kg mouse body weight without changing susceptibility of rats to organophosphorus pesticides. A preliminary administration of perfluorocarbon emulsion effectively increased the protective action of antidotes (atropine + dipyroxime) providing the resistance of the animals to 12-fold, 20-fold and 20-fold LD50 of dichlophos, methaphos and butiphos, respectively. PMID:2226766

Mikha?lov, G M; Varykhanov, A A; Omarova, L A; Verovski?, V E; Obraztsov, V V

269

Mechanisms and efficacy of fluorochemical oxygen transport and delivery.  

PubMed

Fluorochemicals for medical use are metabolically inert liquids with a high solubility for gases, and can dissolve 50 percent or more of their own volume of oxygen (O2) at ambient pressures. The solubility is directly proportional to the oxygen tension (PO2) and transport is thus not saturable, unlike the O2 saturation of hemoglobin (Hb) which follows the well known "S" shaped relationship with PO2. Intravenously-injected emulsions of fluorocarbons transport only about one seventh as much O2 as Hb on a gram for gram basis, even when high concentrations of O2 are respired. However, because of the high O2 extraction from fluorocarbons in these circumstances, their contribution to O2 consumption is more than 65% of that of Hb. O2 delivery to the tissues depends on the product of the cardiac output and the arterial oxygen content. When red cells are transfused, blood viscosity increases and cardiac output decreases. This lessens the efficacy of blood in comparison to that of fluorocarbons, and increases the relative transport of O2 in the metabolically readily-accessible plasma compartment. This provides an interesting application for low dose fluorocarbons during surgery in combination with autologous blood use. The efficacy of fluorocarbons in this setting can be predicted by computer modelling. PMID:8087241

Faithfull, N S

1994-01-01

270

Encapsulation and Release of Amphotericin B from an ABC Triblock Fluorous Copolymer  

PubMed Central

Purpose PEG-phospholipid-based micelles have been successfully used for the solubilization of several hydrophobic drugs but generally lack sustained stability in blood. Our novel PEG-Fluorocarbon-DSPE polymers were designed to increase stability and improve time-release properties of drug-loaded micelles. Methods Novel ABC fluorous copolymers were synthesized, characterized, and used for encapsulation release of amphotericin B. FRET studies were used to study micelle stability. Results The micelles formed by the new polymers showed lower critical micelle concentrations and higher viscosity cores compared with those formed by the polymers lacking the fluorous block. FRET studies indicated that fluorocarbon-containing micelles had increased stability in the presence of human serum. Physicochemical properties and in vitro release profile of the micelles loaded with Amphotericin B (AmB) were studied. Conclusions The effect of PEG length and fluorocarbon incorporation were investigated. The shorter hydrophilic PEG-2K induced greater stability than PEG-5K by decreasing the proportion of hydrophilic block of the polymer. The fluorocarbon placed between hydrophilic and hydrophobic block formed a fluorous shell contributing to the enhanced thermodynamic stability of micelles and to the drug sustained release. Polymer mPEG2K-F10-DSPE, bearing both a fluorocarbon block and a shorter mPEG, showed the greatest stability and the longest half-life for AmB release.

Jee, Jun-Pil; McCoy, Aaron; Mecozzi, Sandro

2011-01-01

271

Surface roughness development on ArF-photoresist studied by beam-irradiation of CF4 plasma  

NASA Astrophysics Data System (ADS)

We report an observed relationship between chemical modifications and physical morphological roughness on a photoresist for ArF excimer laser photolithography in fluorocarbon plasma beam irradiation. At the very beginning period, three stages of characteristics of chemical changes occurred upon surface roughening or wrinkling of the photoresist; (1) a rapid reduction of C = O bonds, (2) gradual formation of a fluorocarbon layer, and graphitic (sp2-C) or amorphous (sp3-C) carbon layer; (3) as elapsed incubation phase, i.e. lag, where reached a steady state of chemical changes for fluorocarbon ion irradiation on the surface; finally morphological changes initiated. Those processes evolved within dose of 6 × 1015 cm-2 for ion energy of a few hundred eV.

Takeuchi, Takuya; Ishikawa, Kenji; Setsuhara, Yuichi; Takeda, Keigo; Kondo, Hiroki; Sekine, Makoto; Hori, Masaru

2013-03-01

272

Formation of boron fluoro-chloride in the separation of boron isotopes by multiphoton absorption of BCl/sub 3/  

SciTech Connect

The reaction products in the process of boron isotope separation by multiphoton absorption of BCl/sub 3/ have been studied. When oxygen was used as the scavenger, the stable solid product was B/sub 2/O/sub 3/, while (BOCl)/sub 3/ was not found. Our experiments have shown that when irradiated by a focused TEA CO/sub 2/ laser beam, BCl/sub 3/ reacted with fluorocarbon grease to form boron fluoro-chloride and boron trifluoride. A possible mechanism for the reaction between BCl/sub 3/ and fluorocarbon grease has been proposed. It seems that BCl/sub 3/ was first dissociated into BCl/sub 2/ and Cl under the intense IR laser action, and BCl/sub 2/ then reacted with fluorocarbon grease to form BFCl/sub 2/. Besides, BF/sub 2/Cl and BF/sub 3/ were formed from BFCl/sub 2/.

Li, L.; Chen, G.; Zhang, R.; Kang, N.

1982-04-01

273

Molecular-ion-beam-assisted deposition of stable SiOF films  

NASA Astrophysics Data System (ADS)

Recently we reported on low refractive index fluorinated silica (SiOF) films obtained by a Molecular Ion Beam Assisted Deposition (MIBAD) process, using a fluorocarbon precursor in an End Hall ion source during evaporation of silica grains. These films were unstable due to moisture absorption and a subsequent chemical reaction, leading to an irreversible change in composition and increase of refractive index. In this paper we investigate an inert gas enhanced MIBAD process, involving the simultaneous use of a fluorocarbon precursor and an inert gas in the ion gun. Ion beam composition was analyzed by energy selective ion mass spectrometry. Addition of inert gas to the fluorocarbon precursor not only increases the total ion current, but also enhances the dissociation of the fluorocarbon precursor into smaller fragments. The films were characterized by ellipsometry, IR transmission spectroscopy and in situ and ex situ stress measurements. Time evolution of film properties was followed for several weeks. For a given fluorocarbon precursor flow rate, refractive index measured directly after deposition increases with increasing inert gas flow rate, while refractive index change with time is reduced. Fluorine content in the films is maximum for low inert gas flow rates, but decreases for higher flow rates to reach approximately the same level as for pure fluorocarbon ion beam. The observed refractive index stabilization for high inert gas flow rates can be explained by a change in film structure rather than film composition, i.e. by reduced film porosity due to high inert gas ion bombardment. With carefully chosen deposition conditions, stable films with low refractive index can be obtained.

Scherer, Karin; Lacan, Pascale; Brunet-Bruneau, Aline; Cado, Herve; Keller, Gerhard J.; Bosmans, Richard; Rivory, Josette

2004-02-01

274

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

SciTech Connect

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%.

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

2000-02-02

275

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

SciTech Connect

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.

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

2000-02-02

276

Plasma fluorination of carbon-based materials for imprint and molding lithographic applications  

PubMed Central

Diamondlike carbon nanoimprint templates are modified by exposure to a fluorocarbon-based plasma, yielding an ultrathin layer of a fluorocarbon material on the surface which has a very low surface energy with excellent antiwear properties. We demonstrate the use of these plasma fluorinated templates to pattern features with dimensions ?20 nm and below. Furthermore, we show that this process is extendable to other carbon-based materials. Plasma fluorination can be applied directly to nanoimprint resists as well as to molds used to form elastomer stamps for microcontact printing and other applications requiring easy mold release.

Schvartzman, M.; Mathur, A.; Hone, J.; Jahnes, C.; Wind, S. J.

2008-01-01

277

Surface alteration of polymer by UV laser ablation  

NASA Astrophysics Data System (ADS)

A polymer surface treatment irradiated system by XeCl excimer laser is designed, bond strengths are measured by shear test method. The bond strengths of fluorocarbon-resin with aluminous bar is improved by solutions such as water (H2O), boric acid (H3BO3), sodium hydroxide (NaOH), bluestone (CuSO4), sodium aluminate (NaAlO2) reacting with fluorocarbon-resin while XeCl excimer laser irradiating. The relationship between the adhesion force with the laser intensity and laser pulse shots are measured. The mechanism of these phenomena is discussed.

Lou, Qihong

1998-10-01

278

Current status of erythrocyte substitutes.  

PubMed Central

During the last two decades the search for alternatives to whole blood transfusions has led to promising developments in the field of erythrocyte substitutes. Hemoglobin solutions free of fragments of erythrocyte stroma and fluorocarbon emulsions are not blood-type-specific and appear likely to satisfy some proportion of our blood requirements. Both must be modified before becoming clinically useful. The oxygen affinity of the hemoglobin solution must be reduced and its intravascular persistence improved. Fluorocarbons cannot yet contribute significantly to the oxygen supply unless the patient breathes hyperbaric oxygen. Recent advances are leading to solutions for these problems.

Biro, G. P.

1983-01-01

279

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

SciTech Connect

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%.

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

2000-02-02

280

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

PubMed

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

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

2010-04-01

281

Effect of Structural Anisotropy on Thermal Ageing in Rigid PU Foams  

Microsoft Academic Search

The use of blowing agents as an alternative to conventional chloro-fluorocarbons (CFCs) and the quality of foaming process can lead to non-homogeneity of the foam structure with the presence of defects along the panel thickness. These defects appear as holes in cell windows or cavities. Accurate measurements of thermal conductivity were made on test specimens having different thicknesses obtained by

A. Boscolo Boscoletto; B. Cellarosi

1992-01-01

282

Effects of Simulated Nuclear Thermal Pulses on Fiber Optic Cables  

Microsoft Academic Search

The effects of pulsed thermal radiation on fiber optic cables with a variety of jackets (polyurethane, PVC, fluorocarbon) are presented. Exposure between 27 and 85 cal\\/cm2 did not sever the optical fibers, but the radiation did cause disintegration of the jackets and the Kevlar strength members, which resulted in a significant reduction of the cable's ability to survive mechanical stress.

A. J. Baba; S. Share; J. H. Wasilik

1979-01-01

283

The Development and Evaluation of Heatresistant, Rain-Erosion-Resistant Coatings.  

National Technical Information Service (NTIS)

A coating based on Viton A, a fluorocarbon polymer, was developed that provides good resistance to rain erosion (abrasion), as determined by the Jet Abrader Method, after exposure to high temperatures or to weathering. The abrasion resistance of Viton A c...

R. B. Perkins

1964-01-01

284

46 CFR 77.30-10 - Stowage.  

Code of Federal Regulations, 2011 CFR

...Self-contained breathing apparatus for refrigeration 1 Flame safety lamps Ocean and...Required only on vessels equipped with any refrigeration unit using ammonia to refrigerate...more than 20 cubic feet or with any refrigeration unit using fluorocarbons to...

2011-10-01

285

46 CFR 77.30-10 - Stowage.  

Code of Federal Regulations, 2012 CFR

...Self-contained breathing apparatus for refrigeration 1 Flame safety lamps Ocean and...Required only on vessels equipped with any refrigeration unit using ammonia to refrigerate...more than 20 cubic feet or with any refrigeration unit using fluorocarbons to...

2012-10-01

286

Acute and Repetitive Human Exposure to Fluorotrichloromethane.  

National Technical Information Service (NTIS)

A total of 28 male and 18 female volunteers were exposed to fluorocarbon-11 (F-11) in a controlled-environment chamber for the purpose of monitoring their physiologic responses to a series of vapor concentrations ranging from 250 to 1000 ppm. The response...

R. D. Stewart E. D. Baretta A. A. Herrmann H. V. Forster J. H. Crespo

1975-01-01

287

Plasma fluorination of diamond-like carbon surfaces: Mechanism and application to nanoimprint lithography  

PubMed Central

Diamond-like carbon (DLC) films, used as molds for nanoimprint lithography, were treated with a fluorocarbon-based plasma in order to enhance their anti-adhesion properties. While elllipsometry and AFM measurements showed negligible changes in thickness and surface roughness after plasma processing, contact angle measurement found fluorine plasma-treated DLC surfaces to be highly hydrophobic, with surface energy values reduced from ~ 45 mJ/m2 for untreated films to ~ 20–30 mJ/m2 after fluorination. XPS revealed a thin (from ~ 0.5 nm to ~ 3 nm) fluorocarbon layer on the DLC surface. Proposed mechanisms for the formation of this layer include two competing processes: etching of DLC and deposition of fluorocarbon material, with one or the other mechanism dominant depending on the plasma conditions. Fluorocarbon plasma-treated DLC molds for nanoimprint lithography were used to pattern sub-20 nm size features with a high degree of repeatability, demonstrating an extended lifetime of the anti-adhesion coating.

Schvartzman, M.; Wind, S. J.

2009-01-01

288

Production of polyurethane foams  

US Patent & Trademark Office Database

There is provided a method of producing an open-cell polyurethane foam comprising heating a mixture of an aqueous emulsion of a polyurethane-forming composition and a fluorocarbon compound of 1 to 3 carbon atoms having a boiling point of 5.degree. to 100.degree. C. The above emulsion may further contain an ionic surfactant.

Tokunaga; Mototsugu (Kyoto, JP)

1983-12-06

289

Nanoenergetics and High Hydrogen Content Materials for Space Propulsion.  

National Technical Information Service (NTIS)

Progress in the past year has occurred in the following areas: 1) understanding the role of pH and rheology on Al/water combustion, 2) encapsulation of nanoparticles in crystals for propellants, 3) disrupting ignition of aluminum with fluorocarbon inclusi...

R. A. Yetter S. F. Son V. Yang

2012-01-01

290

Acute Inhalation Toxicity Evaluation of a 93:7 Mixture of Perfluoro-2- Butene and 1 -Bromopropane, a Replacement Candidate for Ozone Depleting Substances.  

National Technical Information Service (NTIS)

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...

M. L. Feldmann H. F. Leahy A. Vinegar

1997-01-01

291

46 CFR 130.230 - Protection from refrigerants.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Protection from refrigerants. 130.230 Section 130.230...Systems § 130.230 Protection from refrigerants. (a) For each refrigeration...capacity if using a fluorocarbon, as a refrigerant, there must be available one...

2012-10-01

292

46 CFR 128.410 - Ship's service refrigeration systems.  

Code of Federal Regulations, 2012 CFR

...20-10, 58.20-15, 58.20-20(a), or 58.20-20(b) of this chapter ifâ (a) The unit uses a fluorocarbon refrigerant allowed by part 147 of this chapter; (b) The manufacturer certifies that the unit is suitable for its intended...

2012-10-01

293

Global warming and end-use efficiency implications of replacing CFCs  

Microsoft Academic Search

The direct contribution of CFCs to calculated global warming has been recognized for some time. As a result of the international agreement to phase out CFCs due to stratospheric ozone and the ensuing search for suitable alternatives, there has recently been increased attention on the DIRECT global warming potential (GWP) of the fluorocarbon alternatives as greenhouse gases. However, to date

P. D. Fairchild; S. K. Fischer

1991-01-01

294

Evaluation of Plasma-Deposited Hydrophobic Coatings on Pigment-Coated Paper for Reduced Dampening Water Absorption  

Microsoft Academic Search

Hydrophobic plasma coatings were deposited on pigment-coated paper with the purpose of reducing dampening water absorption and create uniform surface chemistry. The influence of plasma coatings on sheet-fed offset printability was also studied. Three plasma chemistries, fluorocarbon, organosilicon and hydrocarbon, were used to adjust the hydrophobicity of paper surface. The plasma coatings reduced, and in some cases prevented, the dampening

M. Pykönen; K. Johansson; M. Dubreuil; D. Vangeneugden; G. Ström; P. Fardim; M. Toivakka

2010-01-01

295

Large area lubricant removal by use of capacitively coupled RF and slot antenna microwave plasma source  

Microsoft Academic Search

Surface cleaning as an important step prior to workplace processing historically relies on the use of wet chemicals. Part of these such as fluorocarbons have been banned because of their detrimental effect on the environment. In the search for alternatives to date a combination of water-based preprocessing followed by a plasma treatment has been found to be most effective. This

D. Korzec; J. Engemann

1997-01-01

296

Multiphase ozonolysis of organics in wastewater by a novel membrane reactor  

Microsoft Academic Search

Conventional ozonation of recalcitrant organic compounds in wastewater suffers from low transfer rate of ozone into water. The low transfer rate can be enhanced by adding an inert fluorocarbon (FC) liquid immiscible with water but having a much higher solubility for ozone. A novel membrane reactor was studied for the destruction of organic pollutants by using FC liquid simultaneously as

Asim K. Guha; V. Shanbhag; Kamalesh K. Sirkar; David A. Vaccari; Deven H. Trivedi

1995-01-01

297

Partitioning of homologous nicotinic acid ester prodrugs (nicotinates) into dipalmitoylphosphatidylcholine (DPPC) membrane bilayers  

Microsoft Academic Search

The partitioning behavior of a series of perhydrocarbon nicotinic acid esters (nicotinates) between aqueous solution and dipalmitoylphosphatidylcholine (DPPC) membrane bilayers is investigated as a function of increasing alkyl chain length. The hydrocarbon nicotinates represent putative prodrugs, derivatives of the polar drug nicotinic acid, whose functionalization provides the hydrophobic character necessary for pulmonary delivery in a hydrophobic, fluorocarbon solvent, such as

Vivian Ojogun; Sandhya M. Vyas; Hans-Joachim Lehmler; Barbara L. Knutson

2010-01-01

298

Evaluation of Containment and Control Options for Methyl Bromide in Commodity Treatment.  

National Technical Information Service (NTIS)

Methyl bromide (MeBr), with the chemical formula CH3Br, also called bromomethane, is listed by the 1991 Montreal Protocol as an ozone depleting chemical similar to the other halogenated hydrocarbons such as the chloro-fluorocarbons (CFCs). The U.S. Enviro...

G. B. DeWolf M. R. Harrison

1994-01-01

299

[Suppression of infarctic changes with mannitol and fluorochemicals--an experimental study].  

PubMed

We have developed and previously reported a canine model for diffuse, incomplete cerebral hemisphere infarction produced by simultaneously occluding the following 5 arteries unilaterally at the base of the brain: the A2 portion of the anterior cerebral artery, the A1 portion of the anterior cerebral artery at the bifurcation of the ethmoidal artery, the internal carotid artery, the posterior cerebral artery at the bifurcation of the posterior communicating artery and the anterior cerebellar artery. After 6 hours of occlusion, recirculation was allowed, and sequential observation was made on the degree of brain swelling. Investigation was made on whether or not administration of 20% mannitol or fluorocarbon emulsion (20% fluosol DA) following vascular occlusion is effective in suppressing such swelling. It was found that brain swelling could be prevented using by mannitol and fluorocarbon emulsion together, but not mannitol and fluorocarbon emulsion alone. Based on these results, we found that mannitol administered together with fluorocarbon emulsion has a protective effect for cerebral infarction following 6 hours vascular occlusion. PMID:6800387

Tanaka, S; Seki, H; Yoshimoto, T; Suzuki, J

1981-11-01

300

Preliminary Evaluation of Greases to 600 F and Solid Lubricants to 1500 F in Ball Bearings  

Microsoft Academic Search

A special apparatus designed for the evaluation of high temperature lubricants in 20 mm bore ball bearings is described. The results of bearing runs at temperatures up to 1500 F in air are reported. Of the greases evaluated, a fluorocarbon grease, provided bearing lubrication for longer times at 450 and 600 F than either polyphenyl ether or silicone greases thickened

H. E. Sliney; R. L. Johnson

1968-01-01

301

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

EPA Science Inventory

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

302

Measurement of radiation damage on an optical reflector  

Microsoft Academic Search

We measured the radiation damage on an optical white fluorocarbon reflector called Goretex, which is to be used for aerogel threshold counters and crystal calorimeters of the BELLE detector of the KEK B-factory. Reflectance of the Goretex surface was monitored to see any effect of the radiation damage. Maximum equivalent dose was 8.6 Mrad. No radiation damage is observed within

K. C Peng; S. K Sahu; H. C Huang; K Ueno; Y. H Chang; C. H Wang; W. S Hou

1997-01-01

303

Coolant controversy heats up  

Microsoft Academic Search

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

Shanley

1997-01-01

304

Quantitative and high mass ToF-SIMS studies of siloxane segregation in hydrogel polymers using cryogenic sample handling techniques  

Microsoft Academic Search

This paper examines the capabilities of cryogenic sample handling to examine composition and structure of hydrogel materials where siloxane components are central to the analysis. XPS analysis of multicomponent polymers with cryogenic sample handling following exposure to aqueous environments has revealed the composition and kinetics of near surface reorganization for siloxane and fluorocarbon containing polymers. In this study we report

Daniel J. Hook; Paul L. Valint; Lu Chen; Joseph A. Gardella

2006-01-01

305

Gas mixtures for spark gap closing switches  

DOEpatents

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.

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

1987-02-20

306

Gas mixtures for spark gap closing switches  

DOEpatents

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.

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

1988-01-01

307

Preparation of PTFE Film With Adhesive Surface Treated by Atmospheric-Pressure Nonthermal Plasma Graft Polymerization  

Microsoft Academic Search

A surface modification technique that improves the adhesion of fluorocarbon polymer films such as polytetrafluoroethylene (PTFE), perfluoroalkoxy fluoroplastics, and polychlorotrifluoroethylene is developed using argon at atmospheric pressure and acrylic acid vapor nonthermal plasma. The results of the T-type peeling test show that the peeling strength of the treated PTFE film is approximately 70 times greater than that of the untreated

Masaaki Okubo; Mitsuru Tahara; Yasushi Aburatani; Tomoyuki Kuroki; Toshitomo Hibino

2010-01-01

308

The Chemistry of Corona Degradation of Organic Insulating Materials in High-Voltage Fields and under Mechanical Strain  

Microsoft Academic Search

Organic materials used as high-voltage electrical insulation are altered chemically and physically by corona discharges. The basic behavior of polyolefin and fluorocarbon resins were investigated under conditions of high electrical stress. The presence of corona subjects a material to ozone, acid, ultraviolet light, and bombardment by electrons and ions. Degradation under these conditions is usually confined to the surface rather

EUGENE J. McMAHON

1968-01-01

309

Estimating and controlling atomic chlorine concentration via actinometry  

Microsoft Academic Search

Actinometry has been used as the basis of a successful sensor for controlling fluorine concentration in fluorocarbon plasmas commonly employed in etching. An analogous sensor would be useful for chlorine plasmas as well. One problem with actinometry in Cl2 plasmas is that excitation can occur by electron impact dissociation and by dissociative attachment, leading to potential ambiguity between the intensity

Courtney K. Hanish; Jessy W. Grizzle

1999-01-01

310

Although best known as synthetic toxicants, thousands of halogen compounds are, in fact, part of our natural environment  

Microsoft Academic Search

he synthetic, chlorine-containing chemicals DDT (dichlorodiphenyl- trichloroethane), dioxin, PCB (poly- chlorinated biphenyl) and CFC (chloro- fluorocarbon) are persistent pollutants in our environment. Less well known— even to many scientists—is that nature produces an abundance of similar, and in some cases identical, halogenated compounds, some of which predate the beginning of life on Earth. From simple, ubiquitous methyl chloride to the

Gordon W. Gribble

311

Electrochemical cell for facilitating hermeticity leakage testing of an electrical feedthrough  

Microsoft Academic Search

An electrical feedthrough, including a metal ferrule, an electrical lead, a glass seal for centrally locating the electrical lead axially within ferrule, for electrically isolating the electrical lead from the ferrule and for hermetically sealing the feedthrough assembly, which further includes an injection molded insulating material extending between the ferrule and lead and a fluorocarbon washer positioned adjacent the inner

E. O. Jurva; R. L. Goodin

1984-01-01

312

Molecular-ion-beam-assisted deposition of stable SiOF films  

Microsoft Academic Search

Recently we reported on low refractive index fluorinated silica (SiOF) films obtained by a Molecular Ion Beam Assisted Deposition (MIBAD) process, using a fluorocarbon precursor in an End Hall ion source during evaporation of silica grains. These films were unstable due to moisture absorption and a subsequent chemical reaction, leading to an irreversible change in composition and increase of refractive

Karin Scherer; Pascale Lacan; Aline Brunet-Bruneau; Herve Cado; Gerhard J. Keller; Richard Bosmans; Josette Rivory

2004-01-01

313

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

ERIC Educational Resources Information Center

|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)|

Richmond, Thomas G.

1995-01-01

314

Heat Transfer Analysis of Air-to-Carbon Dioxide Two-Phase Heat Absorption and Supercritical Heat Rejection  

Microsoft Academic Search

Regulations restricting the present and future use of fluorocarbon-based refrigerants have prompted a worldwide investigation of new refrigerants and refrigeration cycles. In particular, carbon dioxide is a fluid with a history of being used as a refrigerant that has recently been considered for certain applications that may take advantage of its unique thermophysical properties. The high volumetric heat capacity of

Douglas M. Robinson; Eckhard A. Groll

1998-01-01

315

CHEMICAL TECHNOLOGY DIVISION UNIT OPERATIONS SECTION MONTHLY PROGRESS REPORT, MAY 1958  

Microsoft Academic Search

A completely non-metallic pump was fabricated for the circulation of ; polonium-contaminated fluorocarbon. Three emi-continuous DRUHM runs were made to ; test inlet nozle designs. Approximately 11 Ib of UFâ were produced during ; a 12-hr Fluorox run in the new 4-in. fluid bed reactor. Thorium oxalate was ; precipitated by oxalic acid in the esence of amines such as

J. C. Bresee; P. A. Haas; C. D. Watson; M. E. Whatley

1958-01-01

316

Noble gas removal system for post-accident decontamination of power reactors  

Microsoft Academic Search

Oak Ridge has developed a noble gas removal system, as part of the Consolidated Fuel Reprocessing Program, that could be used to help decontaminate the containment vessel of a power reactor following core release of fission gas in the event that containment venting is judged to be unacceptable. The system is based on a fluorocarbon selective absorption process, which has

M. J. Stephenson; B. E. Kanak; D. K. Little; J. R. Merriman; R. C. Riepe

1980-01-01

317

Design and chemical synthesis of iodine-containing molecules for application to solar-pumped I* lasers. Semiannual progress report, 1 January30 June 1986  

Microsoft Academic Search

The design and chemical synthesis of new media for solar pumped iodine molecule lasers are explored. In an effort to prepare an iodo fluorocarbon compound absorbing strongly at 300 nm or above, the synthesis of perfluoro allylic iodides was investigated. These compounds furnish especially stable allylic radicals upon photodissociation. The desired red shift is anticipated in the absorption maximum could

Shiner

1986-01-01

318

Role of extrinsic factors in utilizing the giant magnetocaloric effect on materials: Frequency and time dependence  

Microsoft Academic Search

Magnetic refrigeration (MR) is potentially a high efficiency, low cost, and greenhouse gas-free refrigeration technology, and with the looming phase out of HCFC and HFC fluorocarbons refrigerants is drawing more attention as an alternative to the existing vapor compression refrigeration. MR is based on the magnetocaloric effect (MCE), which occurs due to the coupling of a magnetic sublattice with an

Sesha Chalapathi Madireddi

2010-01-01

319

Lighter-than-Air Science  

ERIC Educational Resources Information Center

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

MOSAIC, 1977

1977-01-01

320

Weak Teratogenic Effect in Rats Exposed to FC22 with Attached Letter to OTS and Customer Advisory Letter.  

National Technical Information Service (NTIS)

We notified the Office of Toxic Substances that we had observed a weak teratogenic effect (small or absent eyes) in rats exposed to fluorocarbon 22 (chlorodifluoromethane, FC-22). Although we were not certain of the significance of this finding for humans...

1978-01-01

321

Biology and Politics  

ERIC Educational Resources Information Center

|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.…

Whiting, Pat

1977-01-01

322

The Great Spray Can Debate.  

ERIC Educational Resources Information Center

|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,…

Bassow, Herb

323

Effect of electron beam irradiation on the properties of crosslinked rubbers  

Microsoft Academic Search

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

Indranil Banik; Anil K Bhowmick

2000-01-01

324

Heat Ageing of Rubbers.  

National Technical Information Service (NTIS)

The oven ageing behaviour of six rubbers (nitrile, polychloroprene, PVC/nitrile, fluorocarbon, EPDM and natural), in the form of tensile dumb-bells has been measured and attempts have been made to relate the ageing behaviour to conventional rate processes...

A. L. Stokoe

1972-01-01

325

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

Microsoft Academic Search

Western Research Institute and the University of Wyoming Enhanced Oil Recovery Institute have tested a novel approach to carbon dioxide capture in power plants and industrial operations. This approach is expected to provide considerable cost savings, in terms of regeneration of the sorbent. It is proposed that low molecular weight, low volatility liquid fluorocarbons be utilized to absorb CO due

William Tuminello; Maciej Radosz; Youqing Shen

2008-01-01

326

Manifold microchannel heat sinks: isothermal analysis  

Microsoft Academic Search

Numerical analyses of manifold microchannel (MMC) heat sinks were performed. The MMC differs from a traditional microchannel heat sink in that the how length is greatly reduced to a small fraction of the total length of the heat sink. Alternating inlet and outlet channels guide the coolant to and from the microchannels. A silicon heat sink cooled by fluorocarbon liquid

David Copeland; Masud Behnia; Wataru Nakayama

1997-01-01

327

Fluids and Elastomers for Low-Temperature Heat Transfer and Hydraulic Systems  

Microsoft Academic Search

Five fluids (a dimethyl silicone, a silicate ester, a branched chain chloro-fluorocarbon, a cyclic fluorinated ether and a fluorinated polyether) were evaluated for use as the fluid in a single pass, gas actuated hydraulic system capable of operation from ?150 to 275 F. Important physical and chemical properties, including thermal stability, lubricity, viscosity, pour, low-temperature characteristics and flash point, were

C. S. Armstrong

1966-01-01

328

Highly fluorinated amphiphiles and colloidal systems, and their applications in the biomedical field. A contribution.  

PubMed

Fluorocarbons and fluorocarbon moieties are uniquely characterized by very strong intramolecular bonds and very weak intermolecular interactions. This results in a combination of exceptional thermal, chemical and biological inertness, low surface tension, high fluidity, excellent spreading characteristics, low solubility in water, and high gas dissolving capacities, which are the basis for innovative applications in the biomedical field. Perfluoroalkyl chains are larger and more rigid than their hydrogenated counterparts. They are considerably more hydrophobic, and are lipophobic as well. A large variety of well-defined, modular fluorinated surfactants whose polar head groups consist of polyols, sugars, sugar phosphates, amino acids, amine oxides, phosphocholine, phosphatidylcholine, etc, has recently been synthesized. Fluorinated surfactants are significantly more surface active than their hydrocarbon counterparts, both in terms of effectiveness and of efficiency. Despite this, they are less hemolytic and less detergent. Fluorosurfactants appear unable to extract membrane proteins. Fluorinated chains confer to surfactants a powerful driving force for collecting and organizing at interfaces. As compared to non-fluorinated analogs, fluorosurfactants have also a much stronger capacity to self-aggregate into discrete molecular assemblies when dispersed in water and other solvents. Even very short, single-chain fluorinated amphiphiles can form highly stable, heat-sterilizable vesicles, without the need for supplementary associative interactions. Sturdy microtubules were obtained from non-chiral, non-hydrogen bonding single-chain fluorosurfactants. Fluorinated amphiphiles can be used to engineer a variety of colloidal systems and manipulate their morphology, structure and properties. Stable fluorinated films, membranes and vesicles can also be prepared from combinations of standard surfactants with fluorocarbon/hydrocarbon diblock molecules. In bilayer membranes made from fluorinated amphiphiles the fluorinated tails segregate to form an internal teflon-like hydrophobic and lipophobic film that increases the stability of the membrane and reduces its permeability. This fluorinated film can also influence the behavior of fluorinated vesicles in a biological milieu. For example, it can affect the in vivo recognition and fate of particles, or the enzymatic hydrolysis of phospholipid components. Major applications of fluorocarbons currently in advanced clinical trials include injectable emulsions for delivering oxygen to tissues at risk of hypoxia; a neat fluorocarbon for treatment of acute respiratory failure by liquid ventilation; and gaseous fluorocarbon-stabilized microbubbles for use as contrast agents for ultrasound imaging. Fluorosurfactants also allow the preparation of a range of stable direct and reverse emulsions, microemulsions, multiple emulsions, and gels, some of which may include fluorocarbon and hydrocarbon and aqueous phases simultaneously. Highly fluorinated systems have potential for the delivery of drugs, prodrugs, vaccines, genes, markers, contrast agents and other materials. PMID:9782389

Krafft, M P; Riess, J G

329

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

PubMed

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

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

2012-06-25

330

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

PubMed

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

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

2009-07-28

331

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

NASA Astrophysics Data System (ADS)

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.

Sokolova, Anastasiya

332

Modelling small angle neutron scattering data from polymers in supercritical fluids  

NASA Astrophysics Data System (ADS)

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). .

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

2000-04-01

333

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

NASA Astrophysics Data System (ADS)

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

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

2013-05-01

334

Thermal oxide growth on silicon: Intrinsic stress and silicon cleaning effects  

NASA Astrophysics Data System (ADS)

This paper summarizes the experimental results and discusses the implications of recent research on two topics related to Si oxidation: mechanical stress effects and the influence of impurities on the Si surface. For stress measurement, a double beam optical technique is used to measure the strain in the Si substrate due to the film stress. An intrinsic SiO2 stress is measured which increses with decreasing oxidation temperature. Controversy exists about whether the intrinsic stress affects transport of oxidant or the interface reaction; arguments for both views are presented. A combination of in-situ ellipsometry and contact angle measurements performed on a Si surface which is used to determine the role of HF in Si cleaning process. A fluorocarbon films was found to replace the removed SiO2, and the fluorocarbon renders the Si surface hydrophobic and amenable to the growth of a high quality SiO2 film for device applications.

Irene, E. A.

1988-09-01

335

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

SciTech Connect

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

William Tuminello; Maciej Radosz; Youqing Shen

2008-11-01

336

Single-phase and boiling cooling of small pin fin arrays by multiple slot nozzle suction and impingement  

Microsoft Academic Search

Experimental measurements of forced convection single-phase and boiling heat transfer from pin fin arrays were made using fluorocarbon liquid FC-72. Liquid flow was directed to and from the pin fin arrays by multiple slot nozzles, alternately providing suction and impingement flow. Rectangular pin fin arrays having equal width and spacing of 0.1 and 0.2 mm and aspect ratios from 1

David Copeland

1995-01-01

337

Single-phase and boiling cooling of small pin fin arrays by multiple slot nozzle suction and impingement  

Microsoft Academic Search

Experimental measurements of forced convection single-phase and boiling heat transfer from pin fin arrays were made using fluorocarbon liquid FC-72. Liquid flow was directed to and from the pin fin arrays by multiple slot nozzles, alternately providing suction and impingement flow. Rectangular pin fin arrays having equal width and spacing of 0.1 and 0.2 mm and aspect ratios of 1,

David Copeland

1994-01-01

338

Pyrolytically prepared carbon from fluorine–GIC  

Microsoft Academic Search

Formation mechanism, crystallinity, porosity and chemical reactivity were studied on the carbon prepared by pyrolysis of single phase, stage-1 fluorine–graphite intercalation compound (fluorine–GIC; CxF). The stage-1 C2.5F directly decomposes to fluorocarbon gases and carbon above 650 K, without forming higher stage compounds. The pyrocarbon prepared from C2.5F gives hkl diffraction peaks indicating graphite-like stacking order of graphene layers. This carbon

Yuta Sato; Soshi Shiraishi; Hirotaka Watano; Rika Hagiwara; Yasuhiko Ito

2003-01-01

339

The Thermal Diffusivity of the Refrigerants R32, R125, and R143a  

Microsoft Academic Search

The thermal diffusivity of the halogenated fluorocarbons R32, R125, and R143a was systematically measured in a wide region of state around the liquid-vapor critical point using dynamic light scattering as the measuring method. The experimental setup is capable of measuring in homodyne (high light intensity) or heterodyne mode (low light intensity). Especially in the vicinity of the critical point, this

M. Pitschmann; J. Straub

2002-01-01

340

International research into chlorofluorocarbon (CFC) alternatives  

SciTech Connect

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.

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

1992-05-01

341

Shocktube studies with incident liquefaction shocks  

Microsoft Academic Search

Incident liquefaction shock waves, with a superheated-vapor upstream state, are studied in shock-tube experiments. Such a shock can occur in any gas, such as n-octane, with a sufficient number of vibrational degrees of freedom: the test fluids in these experiments are fluorocarbons. The shock tube is heated to a test temperature in the range 40-170 C, and a lightweight driver

P. A. Thompson; Y.-G. Kim; G. E. A. Meier

1984-01-01

342

Enhancement of the critical heat flux by using heat spreader  

Microsoft Academic Search

Direct immersion cooling has been considered as one of the promising methods to cool high power density chips. A fluorocarbon\\u000a liquid such as FC-72, which is chemically and electrically compatible with microelectronic components, is known to be a proper\\u000a coolant for direct immersion cooling. However, boiling in this dielectric fluid is characterized by its small value of the\\u000a critical heat

Yong-Sik Yoon; Hyup Yang; Ho-Young Kwak

2003-01-01

343

Linactants: Surfactant Analogues in Two Dimensions  

Microsoft Academic Search

We report a new class of molecules, linactants, that partition at phase boundaries and reduce the line tension between coexisting two-dimensional phases in molecular monolayers. The line tension between hydrocarbon-rich and fluorocarbon-rich phases was determined by monitoring the relaxation kinetics of deformed domains. Two partially fluorinated linactant molecules (with one and two tails, respectively) were synthesized and tested; the more

Siwar Trabelsi; Shishan Zhang; T. Randall Lee; Daniel K. Schwartz

2008-01-01

344

Release of ischemia in paced rat Langendorff hearts by supply of L-carnitine: Role of endogenous long-chain acylcarnitine  

Microsoft Academic Search

Rat Langendorff hearts perfused with media that do not contain erythrocytes or fluorocarbon as oxygen carriers are borderline aerobic during 5 Hz pacing. This follows from the release of catabolic products measured: lactate, urate and lysophosphatidylcholine (IysoPC). Addition of L-carnitine to the perfusion medium reduced the level of these compounds, while the release of long-chain acylcarnitine (LCAC) increased. Previously, we

W. C. Hulsmann; A. Peschechera; F. Serafini; L. E. Ferrari

1996-01-01

345

Highly Selective Si3N4\\/SiOC Etching Using Dual Frequency Superimposed RF Capacitively Coupled Plasma  

Microsoft Academic Search

Highly selective etching of Si3N4 to SiOC film has been studied, using dual frequency superimposed (DFS) rf capacitively coupled plasma, which controlled the self-bias voltage (-Vdc) independently of electron density (Ne). The SiOC etch rate was effectively suppressed by fluorocarbon polymer deposition, which was controlled by the additive H2 gas flow rate ratio and carbon-to-silicon ratio of the SiOC film,

Akihiro Takase; Junya Nishiwaki; Katsumi Yamamoto; Akihiro Kojima; Itsuko Sakai; Hisataka Hayashi; Tokuhisa Ohiwa

2006-01-01

346

General Chemistry Division. Quarterly report, October-December 1979  

SciTech Connect

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

Not Available

1980-02-15

347

Polymer Composites for High-Temperature Proton-Exchange Membrane Fuel Cells  

Microsoft Academic Search

\\u000a Recent advances in composite proton-exchange membranes for fuel cell applications at elevated temperature and low relative\\u000a humidity are briefly reviewed in this chapter. Although a majority of research has focused on new sulfonated hydrocarbon and\\u000a fluorocarbon polymers and their blends to directly enhance high temperature performance, we emphasize on polymer\\/inorganic\\u000a composite membranes with the aim of improving the mechanical strength,

Xiuling Zhu; Yuxiu Liu; Lei Zhu

2009-01-01

348

Relaxation of fluorine nuclei by collisions with free radicals  

Microsoft Academic Search

Intermolecular nuclear relaxation during liquid-state collisions has been examined for 16 combinations of four free radicals and four fluorocarbons. The spectra of electron-induced scalar relaxation transitions are resolved into high- and low-frequency components. All samples are found to have a spectral component with a short correlation time of around 1×10-11 sec, corresponding to fast diffusion-controlled collisions. Those samples which show

Edward H. Poindexter; Philip J. Caplan; Burkhard E. Wagner; Richard D. Bates

1974-01-01

349

Relaxation of fluorine nuclei by collisions with free radicals  

Microsoft Academic Search

Intermolecular nuclear relaxation during liquid-state collisions has been examined for 16 combinations of four free radicals and four fluorocarbons. The spectra of electron-induced scalar relaxation transitions are resolved into high- and low-frequency components. All samples are found to have a spectral component with a short correlation time of around 1×10?11 sec, corresponding to fast diffusion-controlled collisions. Those samples which show

Edward H. Poindexter; Philip J. Caplan; Burkhard E. Wagner; Richard D. Bates Jr

1974-01-01

350

Preparation and characterization of super-hydrophobic and oleophobic surface  

Microsoft Academic Search

A novel method for preparing and characterizing super-hydrophobic and oleophobic surface is presented. Aluminum (Al) substrate\\u000a was roughened by sandblasting and electrolytic etching to obtain micro- and nano-sized complex morphologies. Then, its substrate\\u000a was covered by a chemically adsorbed monolayer (CAM) containing a fluorocarbon group. The surface of Al substrate roughened\\u000a and covered with CAM was observed by scanning electron

Yuji OhkuboIssei TsujiShogo Onishi; Issei Tsuji; Shogo Onishi; Kazufumi Ogawa

2010-01-01

351

Solubility behavior of ethyl cellulose in supercritical fluid solvents  

Microsoft Academic Search

Solubility data to 180°C and 1200 bar are reported for ?1.0 wt.% ethyl cellulose (50% ethoxyl content, 2.5 average degree of substitution) (EC) in neat supercritical fluid (SCF) chlorodifluoromethane (F22); difluoromethane; 1-chloro-1,1-difluoroethane; 1,1-difluoroethane; and dimethyl ether (DME). The pressures needed to dissolve EC in the polar fluorocarbons decreases with increasing solvent size. The exception in this trend is F22 which

Dan Li; Mark A. McHugh

2004-01-01

352

Needs of thermodynamic properties measurements and modeling in the frame of new regulations on refrigerants  

Microsoft Academic Search

In 1987, the Montreal Protocol prohibited the worldwide use and production of chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons\\u000a (HCFCs) and hydro fluorocarbons (HFCs) were proposed as alternative refrigerants. Unfortunately, HFCs have non negligible\\u000a global warning potential and therefore new refrigerants must be proposed or old refrigerants must be used associated with\\u000a HFC. Accurate experimental thermodynamic data and predictive techniques are required for

Christophe Coquelet; Dominique Richon

2007-01-01

353

Thermodynamic and transport properties of some alternative ozone-safe refrigerants for industrial refrigeration equipment: Study in Belarus and Ukraine  

Microsoft Academic Search

The study of several hydrofluorocarbons (HFC) and fluorocarbons (FC) and their binary mixtures that have no ozone-depleting ability is being carried Out in the framework of Belarus National Program. The fluids include HFCs R134a. R152a, R135, and R32, and FC R218. The following properties are being investigated: ( I ) phase equilibrium parameters including the boiling and condensing curve and

A. J. Grebenkov; V. P. Zhelezny; P. M. Klepatsky; O. V. Beljajeva; Yu. A. Chernjak; Yu. G. Kotelevsky; B. D. Timofejev

1996-01-01

354

Mixing behavior of 10-(perfluorohexyl)-decanol and DPPC  

Microsoft Academic Search

Fluorocarbon alcohol such as 10-(perfluorohexyl)-decanol are of interest for novel pulmonary drug delivery approaches. The purpose of this study was to investigate the mixing behavior of 10-(perfluorohexyl)-decanol with dipalmitoylphosphatidylcholine (DPPC), the major component of lung surfactant as an aid in assessing usefulness for this and other biomedical applications. The impact of 10-(perfluorohexyl)-decanol on the phase transitions of DPPC bilayers fully

Hans-Joachim Lehmler; Paul M. Bummer

2005-01-01

355

Ozonation of Fluoroalkenes  

Microsoft Academic Search

Fluorocarbons which have a high capacity to solubilize oxygen and C02 have actually been very well studied, from the point of view of their physical properties and as blood substitutes. Concerning their chemical properties, and in particular their oxidation, we present here the results of ozonolysis of three derivaties of the type R-CH=CH-R:Oxidation products, ozonides obtained under unusual experimental conditions,

Caminade Anne-Marie; Maurice Le Blano; Max Koenig

1986-01-01

356

Improvement in hydrophobicity of polyester fabric finished with fluorochemicals via aminolysis and comparing with nano-silica particles  

Microsoft Academic Search

For the fabrication of the “lotus-type” fibers, a combination of two major requirements, low surface energy and the magnified\\u000a of the degree of roughness, should be utilized. In this research, the possible surface roughening effect of aminolysis of\\u000a the polyester fibers was applied to manipulated surface topography while fluorocarbon polymer layer generates low surface\\u000a energy. The results were compared with

Zahra Mazrouei-Sebdani; Akbar Khoddami; Shadpour Mallakpour

2011-01-01

357

The Effect of Functional Finishes and Laundering on Textile Materials Part I: Surface Characteristics  

Microsoft Academic Search

The effects of finishes and laundering on the surface characteristics of cotton and polyester fibers are evaluated in this investigation. Changes in the surface properties of the fibers are monitored through contact-angle determinations (the Wilhelmy technique) before and after treatment of the fabrics with durable-press, fluorocarbon stain-repellent, and antistatic finishes. The durable-press and stain-repellent finishes did not produce a noticeable

H. Rhee; R. A. Young; A. M. Sarmadi

1993-01-01

358

Synergistic stabilization of perfluorocarbon-pluronic F-68 emulsion by perfluoroalkylated polyhydroxylated surfactants  

Microsoft Academic Search

One of the most serious limitations of the first generation of fluorocarbon emulsions destined to serve as injectable oxygen\\u000a carriers (blood substitutes) is their insufficient, stability. Considerable stabilization of such emulsions has now been achieved\\u000a by using a combination of Pluronic F-68, a polyoxyethylene polyoxypropylene block polymer, and of a perfluoroalkylated polyhydroxylated\\u000a surfactant (PPFS) comprising a C6F13 or C8F17 fluorophilic

Leila Zarif; Alexandre Manfredi; Christian Varescon; Maurice Le Blanc; Jean G. Riess

1989-01-01

359

Heat transfer from grooved surfaces to flow of fluorinert coolant in reduced-size channels  

Microsoft Academic Search

Experiments were conducted in order to investigate the forced convective heat transfer from a grooved surface to a fluorocarbon liquid FX3250. The heat transfer surface is made from copper, has a base area 2×2 cm2, and is equipped with 20 longitudinal fins, each fin being 0.5 mm high and 0.5 mm wide. A particular attention was directed to the effect

Hitoshi Mizunuma; Masud Behnia; Wataru Nakayama

1996-01-01

360

Heat transfer from micro-finned and flat surfaces to flow of Fluorinert coolant; boiling heat transfer  

Microsoft Academic Search

This paper reports the data of forced convection boiling heat transfer from a 2 cm×2 cm simulated chip to a fluorocarbon coolant (FX3250) in a parallel-plate channel. The experimental parameters were the channel height (1 and 5 mm), the simulated chip surface (flat and micro-finned), and the coolant velocity (0.125-4 m\\/s). The effectiveness of longitudinal micro-fins (0.5 mm high×0.5 mm

Hitoshi Mizunuma; Masud Behnia; Wataru Nakayama

1998-01-01

361

Heat transfer from micro-finned surfaces to flow of fluorinert coolant in reduced-size channels  

Microsoft Academic Search

Experiments were conducted in order to investigate the forced convective heat transfer from a micro-finned surface to a fluorocarbon liquid FX3250. The heat transfer surface is made from copper, has a base area 2×2 cm2, and is equipped with 20 longitudinal fins, each fin being 0.5 mm high and 0.5 mm wide. Particular attention was directed to the effect of

Hitoshi Mizunuma; Masud Behnia; Wataru Nakayama

1997-01-01

362

In situ post etching treatment as a solution to improve defect density for porous low-k integration using metallic hard masks  

Microsoft Academic Search

H2, O2, NH3 and CH4 in situ post-etching treatments (PET) have been investigated as a solution to prevent the residues formation (TiFx based) on TiN metallic hard mask (MHM) after etching in fluorocarbon based plasmas. The PET impact on the residues growth reduction on the mask and on the porous SiOCH modification is presented and discussed. The compatibility of the

N. Posseme; R. Bouyssou; T. Chevolleau; T. David; V. Arnal; S. Chhun; C. Monget; E. Richard; D. Galpin; J. Guillan; L. Arnaud; D. Roy; M. Guillermet; J. Ramard; O. Joubert; C. Verove

2009-01-01

363

Measurement of radiation damage on an optical reflector  

NASA Astrophysics Data System (ADS)

We measured the radiation damage on an optical white fluorocarbon reflector called Goretex, which is to be used for aerogel threshold counters and crystal calorimeters of the BELLE detector of the KEK B-factory. Reflectance of the Goretex surface was monitored to see any effect of the radiation damage. Maximum equivalent dose was 8.6 Mrad. No radiation damage is observed within measurement errors.

Peng, K. C.; Sahu, S. K.; Huang, H. C.; Ueno, K.; Chang, Y. H.; Wang, C. H.; Hou, W. S.

1997-02-01

364

Surface-initiated ring-opening metathesis polymerization of 5-(perfluorohexyl)norbornene on carbon paper electrodes  

Microsoft Academic Search

Hydrophobic coatings on carbon paper electrodes are known to provide effective water management, superior gas transfer, and improved mechanical stability of the paper in fuel cell applications. Here, we describe the surface-initiated ring-opening metathesis polymerization (ROMP) of 5-(perfluorohexyl)norbornene (NBF6) to prepare fluorocarbon-rich films on carbon paper substrates that were pre-treated with O2 plasma. For our reaction scheme, the growth of

Christopher J. Faulkner; P. Andrew Payne; G. Kane Jennings

2010-01-01

365

Physical mechanisms for anisotropic plasma etching of cesium iodide  

Microsoft Academic Search

The physical mechanisms for the interaction between a reactive plasma and a cesium iodide surface are investigated. Under conditions of ion bombardment and elevated substrate temperature, CsI is found to sputter etch slowly (15 nm\\/min). If atomic fluorine, fluorocarbon radicals, of SFx radicals are present in the discharge, however, CsI is reactively etched at substantially higher rates (up to 200

Xiaoji Yang; Jeffrey A. Hopwood

2004-01-01

366

Perfluorohexyloctane as a long-term vitreous tamponade in the experimental animal  

Microsoft Academic Search

Background: Perfluorocarbon liquids are established tools for intraoperative hydrokinetic retinal manipulation. Because of their high specific gravity, however,they may well cause mechanical damage to the retina whenapplied as a long-term vitreous substitute.Perfluorohexyloctane, a semi-fluorinated liquid fluorocarbon of low specific gravity (1.35 g\\/cm3), was developed as a long-term vitreous substitute. The current study was performed to investigate intraocular tolerance to perfluorohexyloctane

Damiana Zeana; Jacob Becker; Ralf Kuckelkorn; Bernd Kirchhof

1999-01-01

367

Synthesis of fluorine-containing block copolymers via ATRP 2. Synthesis and characterization of semifluorinated di- and triblock copolymers  

Microsoft Academic Search

A series of semifluorinated fluorocarbon\\/hydrocarbon di- and triblock copolymers were prepared by atom transfer radical polymerization (ATRP). The mono- and difunctional macroinitiators, which were obtained from bulk ATRP of styrene, butyl acrylate and methyl acrylate, initiated solution ATRP of 2-[(perfluorononenyl)oxy]ethyl methacrylate and ethylene glycol mono-methacrylate mono-perfluorooctanoate, respectively. The formation of the block copolymer was confirmed with size exclusion chromatography and

Z.-B. Zhang; S.-K. Ying; Z.-Q. Shi

1999-01-01

368

Electrochemical cell for facilitating hermeticity leakage testing of an electrical feedthrough  

SciTech Connect

An electrical feedthrough, including a metal ferrule, an electrical lead, a glass seal for centrally locating the electrical lead axially within ferrule, for electrically isolating the electrical lead from the ferrule and for hermetically sealing the feedthrough assembly, which further includes an injection molded insulating material extending between the ferrule and lead and a fluorocarbon washer positioned adjacent the inner surface of the glass seal. The fluorocarbon washer is capable of retaining helium and allows for the hermeticity leakage testing of the glass seal. Such a feedthrough is particularly useful in hermetically sealed electrochemical cells wherein the insulated portion of the feedthrough is placed in the cell and the uninsulated portion of the ferrule is welded to or forms the cell cover, and the electrical lead is electrically connected to cell components, such as the anode, within the cell. The hermeticity testing of the aforementioned cell is accomplished by constructing the electrical feedthrough with the teflon washer in position; attaching the feedthrough to the hermetically sealed cells; placing the completed electrochemical cell in a pressurized atmosphere of a test gas, such as helium, for a period of time to force the test gas through the glass seal into the chamber containing the fluorocarbon washer, whereby the fluorocarbon washer absorbs helium gas; and examining the electrochemical cell for leakage of any of the helium back out through the glass seal. Gross and fine leakage testing may be accomplished by respectively observing the escape of the test gas at atmospheric pressure and drawing a vacuum on the electrical feedthrough and testing for the escape of the test gas with a mass spectrometer.

Jurva, E.O.; Goodin, R.L.

1984-07-17

369

Investigation of the hermeticity of BCB-sealed cavities for housing (RF)MEMS devices  

Microsoft Academic Search

This paper reports on the hermeticity testing of MEMS cavities using BCB as the sealing and bonding material. Hermeticity has been tested according to the MIL-STD-883D. Gross leak testing based on liquid fluorocarbons revealed that BCB sealed cavities are leak tight, which means that the MEMS devices are well protected during handling and back-end processing (e.g., wafer dicing). Further, it

A. Jourdain; P. De Moor; S. Pamidighantam; H. A. C. Tilmans

2002-01-01

370

Application of a novel disposable film culture system to photoautotrophic micropropagation of Eucalyptus uro-grandis (Urophylia x grandis)  

Microsoft Academic Search

Summary  To overcome various disadvantages of conventional culture vessls for plant micropropagation, we previously developed the photoautotrophic\\u000a micropropagation technique, with special mention for the first practical film culture system, the ‘Miracle Pack’ (MP), which\\u000a was made of fluorocarbon polymer film (Neoflo PFA film) and supported by a polycarbonate frame. While the PFA film has superior thermal stability, high light transmittance\\u000a and

M. Tanaka; Dam Thi Thanh Giang; A. Murakami

2005-01-01

371

Uptake of trifluoroacetate by Pinus ponderosa via atmospheric pathway  

NASA Astrophysics Data System (ADS)

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.

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

372

Novel low-permittivity dielectrics for Si-based microelectronics  

Microsoft Academic Search

The purpose of this laboratory-directed research and development (LDRD) project was to develop and assess novel low-permittivity dielectric materials for applications as interlevel dielectrics (ILDs) in Si-based microelectronics. There were three classes of materials investigated: (1) novel covalently-bonded ceramics containing carbon, boron, and\\/or nitrogen, (2) fluorinated SiOâ (SiOF), and (3) plasma polymerized fluorocarbon (PPFC). The specific advantages and disadvantages for

1997-01-01

373

Effects of low-molecular-weight radicals for reduction of microloading in high-aspect contact-hole etching  

Microsoft Academic Search

SiO2 etching is done by using fluorocarbon gases to deposit a fluoropolymer on the underlying silicon. This deposit enhances the etching selectivity of SiO2 over silicon or silicon nitride. CF2 radicals are used as the main gas precursor for polymer deposition. In a conventional gas plasma, however, the CF2 radicals and other radicals (high-molecular-weight radicals: CxFy) lead to polymerization. This

Seiji Samukawa; Tomonori Mukai

2000-01-01

374

Selective Plasma Etching for High-Aspect-Ratio Oxide Contact Holes  

Microsoft Academic Search

The effects of pressure and CH2F2 percentage on the selectivity of oxide to photoresist (oxide:PR) and on reactive ion etch (RIE) lag in a helicon wave high-density CF4\\/CH2F2 plasma are reported. Operating the helicon source in high-pressure (20 30 mTorr) fluorocarbon and hydrofluorocarbon plasmas results in highly selective oxide etching. By independently controlling the formation rate of depositing polymer precursors,

Yun-Sang Kim; Peter Ta-Chin Wei; George R. Tynan; Robert Charatan; Dave Hemker

1998-01-01

375

Contamination rates of optical surfaces at 157 nm: impurities outgassed from construction materials and from photoresists  

Microsoft Academic Search

Photo-induced contamination rates on 157-nm optical surfaces have been studied in controlled experiments with contaminants containing fluorocarbon, sulfur and iodine. The compounds investigated represent species generated in controlled outgassing studies of common construction materials and photoresists used in 157 nm steppers. No photocontamination was measured for highly fluorinated alkanes and ethers on an anti-reflective coating, at levels exceeding 10 ppm.

Theodore M. Bloomstein; Jan H. C. Sedlacek; Stephen T. Palmacci; Dennis E. Hardy; Vladimir Liberman; Mordechai Rothschild

2003-01-01

376

Survival of adhering cortical neurons on polyethylenimine micropatterns  

Microsoft Academic Search

The influence of neuron-adhesive pattern geometry on long-term survival of cortical neural tissue (rat brain) was studied over a time period of 15 days. Microwells (depth 0.5 ?m) with diameters of 25, 50, 100 and 150 ?m and inter-microwell distances of 15, 30, 60 and 90 ?m, were etched in a neuron-repellent fluorocarbon (FC)-layer and coated with neuron-adhesive polyethylenimine (PEI).

T. G. Ruardij; M. H. Goedbloed; W. L. C. Rutten

2001-01-01

377

Contraband Detection with Nuclear Resonance Fluorescence: Feasibility and Impact  

SciTech Connect

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.

Pruet, J; Lange, D

2007-01-03

378

Climate Change, Air Pollution, and the Economics of Health Impacts  

Microsoft Academic Search

Climate change and air pollution are intricately linked. The distinction between greenhouse substances and other air pollutants is resolved at least for the time being in the context of international negotiations on climate policy through the identification of CO2, CH4, N2O, SF6 and the per- and hydro- fluorocarbons as substances targeted for control. Many of the traditional air pollutant emissions

J. Reilly; T. Yang; S. Paltsev; C. Wang; R. Prinn; M. Sarofim

2003-01-01

379

MEMS packaging process by film transfer using an anti-adhesive layer  

Microsoft Academic Search

A low cost and low temperature thin film packaging process based on the transfer of an electroplated Nickel 3D cap is proposed.\\u000a This process is based on adhesion control of a thick molded cap Ni film on the carrier wafer by using a plasma deposited fluorocarbon\\u000a film, on mechanical debonding and on adhesive bonding of the microcaps on the host

Sebastien Brault; O. Garel; G. Schelcher; N. Isac; F. Parrain; A. Bosseboeuf; F. Verjus; M. Desgeorges; E. Dufour-Gergam

2010-01-01

380

Removal of C2F6 from semiconductor process flue gases by ferro-electric packed-bed barrier discharge reactor-adsorbent hybrid systems  

Microsoft Academic Search

Removal of greenhouse gases from semiconductor process flue gas is becoming a significant problem since not only methane and\\/or nitrous oxide are exhausted but also high concentrations of fluoride and para-fluorocarbons (PFCs) such as NF3, C2F6 , SF6, and CF4, are exhausted during the wafer etching or PECVD chamber cleaning processes. In this work, the removal of C2F6 from a

K. Urashima; K. G. Kostov; J. S. Chang; Y. Okayasu; T. Iwaizumi; K. Yoshimura; T. Kato

1999-01-01

381

Gas-jet method for deposition of metal nanoparticles into the fluorine-polymer matrix  

NASA Astrophysics Data System (ADS)

The work deals with the obtaining by the vacuum gas-jet technique of the metal-polymer composites consisting of silver nanoparticles introduced into a fluorocarbon polymer matrix and the investigation of their optical properties. The dependence of the optical density in the visible range of frequencies on the structure of obtained samples has been investigated. The obtained composites are found to possess the plasmon resonance effect.

Andreev, M. N.; Bespalov, I. S.; Safonov, A. I.

2013-09-01

382

Nonlinear evolution of surface morphology under shadowing.  

PubMed

Fluorocarbon thin-film deposition is studied, which shows an anomalous high dynamic growth exponent and therefore does not fit in any universal class of fractal surface growth models. A detailed analysis of the nonlinear behavior of the surface morphology evolution is carried out, quantifying several features of the shadowing instability. A synergy effect with the Kardar-Parisi-Zhang nonlinearity, which couple the large scales induced by shadowing with intermediate scales, may explain the anomalous high growth exponent. PMID:23679426

Manz, P; Fedorczak, N; Dittmar, T; Baloniak, T; von Keudell, A

2013-04-10

383

CO-Oximetry interference by perflubron emulsion: comparison of hemolyzing and nonhemolyzing instruments  

Microsoft Academic Search

Perflubron emulsion is expected to be in clinical use soon as a non-hemoglobin blood substitute. A prelimi- nary report indicates that this new oxygen-carrying fluorocarbon interferes with the measurements of CO- oximeters. Therefore, we have quantified the interfer- ence that perflubron causes in the measurements of eight widely used oximeters and CO-oximeters. The AVL Omni 6, CC270, IL482, IL682, and

A. P. Shepherd; J. M. Steinke

1998-01-01

384

Isoflurane leakage from non-rebreathing rodent anaesthesia circuits: comparison of emissions from conventional and modified ports  

Microsoft Academic Search

Summary Chronic exposure to low levels of fluorocarbon-based waste anaesthetic gas (WAG) has been linked to a multitude of human health problems. We have shown that isoflurane exhaust from passive gas-scavenging canisters is often quite high when using conventional rodent anaesthesia protocols and equipment. Another likely source of WAG build-up in rodent procedure rooms is leakage at the interface between

J C Smith; B Bolon

2006-01-01

385

Midwestern efforts to address climate change  

Microsoft Academic Search

Six Midwestern governors and a Canadian premier signed the Midwestern Greenhouse Gas Reduction Accord in November 2007. The governors agreed to begin the process of developing a market-based cap-and-trade program that would reduce GHG emissions (e.g., carbon dioxide, methane, nitrous oxide, hydro-fluorocarbons, perfluorocarbons, and sulfur hexafluoride) to meet reduction targets. Member jurisdictions include Illinois, Iowa, Kansas, Manitoba, Michigan, Minnesota, and

Daniel Stenberg

2008-01-01

386

A novel lyotropic liquid crystal formed by triphilic star-polyphiles: hydrophilic/oleophilic/fluorophilic rods arranged in a 12.6.4. tiling.  

PubMed

Triphilic star-polyphiles are short-chain oligomeric molecules with a radial arrangement of hydrophilic, hydrocarbon and fluorocarbon chains linked to a common centre. They form a number of liquid crystalline structures when mixed with water. In this contribution we focus on a hexagonal liquid crystalline mesophase found in star-polyphiles as compared to the corresponding double-chain surfactant to determine whether the hydrocarbon and fluorocarbon chains are in fact demixed in these star-polyphile systems, or whether both hydrocarbon and fluorocarbon chains are miscible, leading to a single hydrophobic domain, making the star-polyphile effectively amphiphilic. We report SANS contrast variation data that are compatible only with the presence of three distinct immiscible domains within this hexagonal mesophase, confirming that these star-polyphile liquid crystals are indeed hydrophilic/oleophilic/fluorophilic 3-phase systems. Quantitative comparison with scattering simulations shows that the experimental data are in very good agreement with an underlying 2D columnar (12.6.4) tiling. As in a conventional amphiphilic hexagonal mesophase, the hexagonally packed water channels (dodecagonal prismatic domains) are embedded in a hydrophobic matrix, but that matrix is split into oleophilic hexagonal prismatic domains and fluorophilic quadrangular prismatic domains. PMID:21103506

de Campo, Liliana; Varslot, Trond; Moghaddam, Minoo J; Kirkensgaard, Jacob J K; Mortensen, Kell; Hyde, Stephen T

2010-11-22

387

Pretreatment of Kapton-coated cable for epoxy adhesion  

SciTech Connect

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

Carley, J.F.

1984-01-09

388

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

PubMed Central

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

Li, Xueshu; Turanek, Jaroslav; Knotigova, Pavlina; Kudlackova, Hana; Masek, Josef; Parkin, Sean; Rankin, Stephen E; Knutson, Barbara L; Lehmler, Hans-Joachim

2009-01-01

389

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

NASA Astrophysics Data System (ADS)

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

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

390

Fluorous protic ionic liquids exhibit discrete segregated nano-scale solvent domains and form new populations of nano-scale objects upon primary alcohol addition.  

PubMed

Fluorous protic ionic liquids (FPILS) containing a perfluorinated anion and hydrocarbon cation have been observed to segregate into nano-scale fluorocarbon, hydrocarbon and polar domains. The solubility and interactions of ethanol and butanol in a series of FPILs has been investigated by synchrotron source small and wide angle X-ray scattering. Nano-scale objects were found to be present within the binary solutions from low concentrations of FPILs in alcohols to around 40 to 80 wt% FPIL. The FPILs retain their fluorocarbon, hydrocarbon and polar domains in binary mixtures with alcohols in addition to the formation of nano-scale alcohol associated objects. For comparison, the influence of alcohols on the nano-scale segregation of analogous protic ionic liquids (PILs) which contained hydrocarbon anions in place of the perfluorinated anions was also investigated. The ethanol and butanol were miscible with the PILs across the full concentration range, with no evidence for the formation of analogous nano-scale objects. The FPILs are prospective solvents which may enable simultaneous solubility of fluorocarbon, hydrocarbon and polar species. PMID:23588776

Greaves, Tamar L; Kennedy, Danielle F; Shen, Yan; Hawley, Adrian; Song, Gonghua; Drummond, Calum J

2013-04-15

391

Fluorophilicity of Alkyl and Polyfluoroalkyl 1 Nicotinic Acid Ester Prodrugs.  

PubMed

The fluorophilicity of a series of hydrocarbon and fluorocarbon-functionalized nicotinic acid esters (nicotinates) is measured from their partitioning behavior (log K(P)) in the biphasic solvent system of perfluoro(methylcyclohexane) (PFMC) and toluene. The chain length of the hydrocarbon or fluorocarbon alkyl group of the ester ranges from one to twelve carbon atoms. Knowledge of the fluorophilicity of these solutes is relevant to the design of these prodrugs for fluorocarbon-based drug delivery. The experimental log K(p) values range from -1.72 to -3.40 for the hydrocarbon nicotinates and -1.64 to 0.13 for the fluorinated nicotinates, where only the prodrug with the longest fluorinated chain (2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctyl nicotinic acid ester) partitions preferentially into the fluorinated phase (log K(p) = 0.13). Predictions of the partition coefficients using solubility parameters calculated from group contribution techniques or molecular dynamics simulation are in reasonable agreement for the perhydrocarbon nicotinates and short chained perfluorinated nicotinates (? 0.3%-39% deviation). Significant deviations from experimental partition coefficients (greater than 100%) are observed for the longest chain perfluoroalkyl nicotinates. PMID:20567608

Ojogun, Vivian; Knutson, Barbara L; Vyas, Sandhya; Lehmler, Hans-Joachim

2010-07-01

392

Aerobic preservation of organs using a new perflubron/lecithin emulsion stabilized by molecular dowels.  

PubMed

The purpose of the study reported here was to explore a new strategy for the aerobic preservation of transplants using stable concentrated fluorocarbon emulsions as an oxygen delivery system. Fluorocarbons (FCs) are synthetic molecules, chemically and biologically inert, with a high oxygen-dissolving capacity. As they do not mix with water, it is necessary to emulsify them for intra-vascular use. Perfluorooctyl bromide (or perflubron) can be emulsifled with egg-yolk phospholipid (EYP), a nontoxic emulsifiant. The recent adjunction of amphiphilic fluorocarbon-hydrocarbon diblock molecules allows the obtaining of stable emulsions. By contrast with hemoglobin, fluorocarbons release oxygen following Henry's linear law rather than Barcroft's sigmoid curve. Release of oxygen by the FCs is only slightly influenced by temperature, which is an advantage for the preservation of organs. We tested a new 90% w/v fluorocarbon stem emulsion (perflubron/EYL/F6H10) diluted to 36% w/v with a hydroelectrolytic solution containing albumin, on four multiple organ blocks (MOBs; heart-lungs, liver, pancreas, kidneys, small intestine) of rats (EMOBs). Five control MOBs were perfused with a 50% v/v mixture of rat-blood and Krebs solution (KBMOBs). The lungs were ventilated with a FiO2 = 100%. In all cases the survival of the MOBs was greater than 210 min, with stable hemodynamics and preserved hydroelectrolytic and acid-base balances. The levels of lactate, amylase, and CK of the EMOBs were inferior (P < 0.05) to those of the KBMOBs between the first and the second hour. The diuresis of the EMOBs was higher (P < 0.05) than that of the KBMOBs (5.65 +/- 1.76 vs 1.21 +/- 0.28 mg/min). The production of bile, and the AST and ALT levels, were not significantly different. The PaO2 of the EMOBs was higher (P < 0.01) than for the KBMOBs. In normothermy, the maintenance of an aerobic metabolism using the FC emulsion caused less damage to the organs. Aerobic preservation of organs using FC emulsions therefore appears to be an attractive alternative to the presently used cold ischemia. PMID:8661239

Voiglio, E J; Zarif, L; Gorry, F C; Krafft, M P; Margonari, J; Martin, X; Riess, J; Dubernard, J M

1996-07-01

393

Spectroscopic study of gas and surface phase chemistries of CF{sub 4} plasmas in an inductively coupled modified gaseous electronics conference reactor  

SciTech Connect

Gas and surface phase chemistries of CF{sub 4} plasma were studied in an inductively coupled modified gaseous electronics conference reference cell, using in situ Fourier transform infrared spectroscopy enhanced by a multipass White cell and in situ spectroscopic ellipsometry. The self-bias dc voltage, densities of gaseous species, fluorocarbon film thickness on Si substrate, as well as etch rates of SiO{sub 2} and Si were measured during plasma processing as functions of the pressure, CF{sub 4} gas flow rate, rf source power, platen bias power, and source-platen gap. The gaseous molecules and radicals monitored included CF{sub 4}, CF{sub 3}, CF{sub 2}, SiF{sub 4}, and COF{sub 2}, among which CF{sub 4} and SiF{sub 4} were found to be the two dominant species, combining for about 80% of the total concentration. The density ratio of SiF{sub 4} and COF{sub 2} was about 2:1 with no bias on the substrate and increased up to {approx}8:1 when Si substrate etching took place. Specifically, as the Si etch rate increased, the COF{sub 2} density dropped, likely due to suppressed etching of the quartz source window, while the density of SiF{sub 4} increased. Comparisons between the gas phase data and etch rate results of Si and SiO{sub 2} indicate that the gas phase chemistry is strongly influenced by surface reactions on the substrate, wall, and quartz source window. The thickness of fluorocarbon reaction layer on Si substrate is mainly determined by densities of fluorocarbon radicals and fluorine atoms in the bulk plasma as well as the self-bias voltage on the substrate, and a thicker film is usually associated with a lower etch rate.

Zhou Baosuo; Joseph, Eric A.; Overzet, Lawrence J.; Goeckner, Matthew J. [Department of Electrical Engineering, University of Texas at Dallas, Richardson, Texas 75083 (United States)

2006-01-15

394

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

SciTech Connect

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

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

1982-05-21

395

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

NASA Astrophysics Data System (ADS)

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

Demuth, O. J.

1981-02-01

396

Phenolic's fire resistance, high R-value said to cut costs  

SciTech Connect

Phenolic foam board can achieve a specified R-value with less material and lower handling and installation cost than other insulating materials. The new product has a flame resistance that permits application without a thermal barrier. Competitors point out that its value will not be proven until it has widespread application. The two producers are currently making R-8.33 closed-cell insulation, which binds fluorocarbon gas and prevents heat loss and R-5 open-cell insulation. Insurance companies recognize the flame resistance of both, and set their rates accordingly. A directory lists major supplies of roof and wall insulation. (DCK)

Duffy, J.

1983-05-16

397

Fluorine-Based Mechanisms for Atomic-Layer-Epitaxial Growth on Diamond (110)  

NASA Astrophysics Data System (ADS)

Atomic-layer-epitaxy (ALE) processes for the growth of diamond are evaluated using ab initio molecular dynamics. It is shown that the Cl-based ALE cycle on diamond (111) is not advantageous, due to strong steric hindrances. New ALE processes are proposed and shown to be energetically favorable, self-limiting, and sterically unhindered. They exploit the large heat of formation and the small size of the HF molecule and are based on alternating exposure of the diamond (110) surface to hydrocarbons and fluorocarbons. Alternatively, H and F gases can be used in parts of the cycle.

Wensell, M. G.; Zhang, Z.; Bernholc, J.

1995-06-01

398

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

NASA Astrophysics Data System (ADS)

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

Beck, T. R.

2013-02-01

399

Low viscosity liquid fluorochemicals in vitreous surgery.  

PubMed

Low viscosity liquid fluorocarbons have physical properties potentially useful as intraoperative adjuncts during vitreous surgery for complicated retinal detachments. These substances are optically clear, have specific gravity greater than that of water, and interfacila tension properties similar to those of silicone oil. In four patients who had complicated retinal detachments I used perfluorotributylamine and perfluorodecalin during vitreous surgery. Two giant retinal tears were flattened intraoperatively without turning the patient into the prone position. In two patients with severe proliferative vitreoretinopathy, perfluorotributylamine allowed adequate retinal tamponade and avoided a posterior retinotomy for internal drainage of subretinal fluid. Endophotocoagulation was applied. PMID:3799788

Chang, S

1987-01-15

400

Downstream electron beam exciter diagnostic with energy dependent cross section responses for process tool applications  

NASA Astrophysics Data System (ADS)

Optical emission spectroscopy (OES) still remains as the primary diagnostic in plasma process tools in micro-electronics industry. With newer plasma processes and detection demands in low open area etches, process monitoring with direct optical signals is severely limited. Here we present a diagnostic method that realizes optical signals due to an electron beam from an inductively coupled plasma. Distinct merits such as energy dependent optical emission cross section responses and stable operability in polymerizing / corrosive etch environments will be presented. Electron impact optical cross section responses of transitions in fluorocarbon, oxygen and inert gas chemistries will be shown. Such controllability, in the context of species density measurement will be discussed.

Thamban, P. L. Stephan; Padron Wells, Gabriel; Hosch, Jimmy; Goeckner, Matthew

2011-10-01

401

Hydrodefluorination of fluorobenzene and 1,2-difluorobenzene under mild conditions over rhodium pyridylphosphine and bipyridyl complexes tethered on a silica-supported palladium catalyst  

SciTech Connect

The C-F bond, which is the strongest bond that carbon can form, is extremely reluctant to coordinate to metal centers and is resistant to chemical attack. Although this lack of fluorocarbon reactivity has frequently been exploited in technological and medical applications, this chemical inertness also translates into environmental persistence since these compounds are quite difficult to degrade. Fluorobenzene and 1,2-difluorobenzene are defluorinated under very mild conditions by H{sub 2}(4 atm) at 70 C in the presence of NaOAc. The heterogeneous catalysts for these reactions contain the rhodium pyridylphosphine and bipyridyl complexes tethered to heterogeneous Pd-SiO{sub 2}.

Yang, H.; Gao, H.; Angelici, R.J. [Iowa State Univ., Ames, IA (United States). Ames Lab.

1999-06-07

402

Robust Cu Dual Damascene Interconnects With Porous SiOCH Films Fabricated by Low-Damage Multi-Hard-Mask Etching Technology  

Microsoft Academic Search

Low-damage hard-mask (HM) plasma-etching technology for porous SiOCH film (k=2.6) has been developed for robust 65-nm-node Cu dual damascene interconnects (DDIs). No damage is introduced by fluorocarbon plasma etching irrespective of whether rigid (k=2.9) or porous (k=2.6) SiOCH films are used, due to the protective CF-polymer layer deposited on the etched sidewall. The etching selectivity of the SiOCH films to

Hiroto Ohtake; Masayoshi Tagami; Munehiro Tada; Makoto Ueki; Mari Abe; Shinobu Saito; Fuminori Ito; Yoshihiro Hayashi

2006-01-01

403

Direct spectroscopic observation of singlet oxygen emission at 1268 nm excited by sensitizing dyes of biological interest in liquid solution  

PubMed Central

The direct observation of dye-photosensitized 1268-nm emission of the 1?g ? 3?g transition of molecular oxygen in liquid solution at room temperature is reported. Singlet oxygen was photosensitized by UV excitation of perfluorobenzophenone in fluorocarbon solvent, by 3,4-benzpyrene and hematoporphyrin in carbon tetrachloride, and by methylene blue in water. Also reported is the development of an extremely sensitive near-infrared spectrophotometer that uses a thermoelectrically cooled lead sulfide detector, optimized optics, and a boxcar integrator as a data processor.

Khan, A. U.; Kasha, M.

1979-01-01

404

Telemetry engineering and fabrication alternative soldering techniques for CFC elimination  

SciTech Connect

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

Howard, R.V.

1995-08-01

405

Nano-particulate coating on cotton fabric through DBD  

NASA Astrophysics Data System (ADS)

Plasma polymerization of fluorocarbon was processed through dielectric barrier discharge (DBD). A thin hydrophobic film packed with nano-particulate structure was obtained on cotton fabric surface. The contact angle of the water and 1-bromonaphthalene on coated cotton fabric was 133° and 124° separately. The surface morphology of the coating was observed through SEM (Scanning Electronic Microscope). It was found that cotton fabric surface was tightly adhered to a thin film packed by nano-particles from 10nm to 200nm. This process showed potential applications in continuous coating of textiles with functional nano-particulate polymers, but without changing their softness performance.

Guo, Ying; Zhang, Jing; Xu, Jinzhou; Zhou, Rongming; Yu, Jianyong

2008-03-01

406

Linactants: Surfactant Analogues in Two Dimensions  

NASA Astrophysics Data System (ADS)

We report a new class of molecules, linactants, that partition at phase boundaries and reduce the line tension between coexisting two-dimensional phases in molecular monolayers. The line tension between hydrocarbon-rich and fluorocarbon-rich phases was determined by monitoring the relaxation kinetics of deformed domains. Two partially fluorinated linactant molecules (with one and two tails, respectively) were synthesized and tested; the more efficient single-tail variant reduced the line tension by more than 20% at a mole fraction of only 8×10-4.

Trabelsi, Siwar; Zhang, Shishan; Lee, T. Randall; Schwartz, Daniel K.

2008-01-01

407

Linactants: surfactant analogues in two dimensions.  

PubMed

We report a new class of molecules, linactants, that partition at phase boundaries and reduce the line tension between coexisting two-dimensional phases in molecular monolayers. The line tension between hydrocarbon-rich and fluorocarbon-rich phases was determined by monitoring the relaxation kinetics of deformed domains. Two partially fluorinated linactant molecules (with one and two tails, respectively) were synthesized and tested; the more efficient single-tail variant reduced the line tension by more than 20% at a mole fraction of only 8 x 10(-4). PMID:18233038

Trabelsi, Siwar; Zhang, Shishan; Lee, T Randall; Schwartz, Daniel K

2008-01-23

408

Comparative Studies of Perfluorocarbon Alternative Gas Plasmas for Contact Hole Etch  

Microsoft Academic Search

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

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

2003-01-01

409

A comparative study on a high aspect ratio contact hole etching in UFC and PFC-containing plasmas  

Microsoft Academic Search

An etching of a SiO2 contact hole with a diameter of 0.19?m and an aspect ratio of 13, using C4F6\\/Ar\\/O2\\/CH2F2 and c-C4F8\\/Ar\\/O2\\/CH2F2 plasmas, was performed for a feasibility test of the use of unsaturated fluorocarbons (UFCs) as an alternative to perfluorocarbon (PFC) gases for a high aspect ratio contact hole etching. The etch profile of the contact hole obtained in

Hyun-kyu Ryu; Yil-wook Kim; Kangtaek Lee; Cheeburm Shin; Chang-koo Kim

2007-01-01

410

Study on the binding of trichloromonofluoromethane by bovine serum albumin using a fluorescent probe technique.  

PubMed

Protein binding of the aerosol propellant, trichloromonofluoromethane, was studied in bovine serum albumin (BSA) solutions using the fluorescent probe technique. The propellant displaced the probe, 8-anilino-1-naphthalenesulfonate, from its binding sites and reduced the fluorescence intensity. The binding association constants, the number of binding sites, and the competitive nature of the binding interaction were investigated. The hydrophobic nature of the binding and the implication of binding displacement interactions between the fluorocarbon and plasma-protein-bound drugs were also discussed. The fatty acid impurities present in the commercial BSA were found to have no effect on the protein binding of the propellant. PMID:986655

Peng, G W; Chiou, W L

1976-01-01

411

Biotransformation of trans-1,1,1,3-tetrafluoropropene (HFO1234ze)  

Microsoft Academic Search

trans-1,1,1,3-Tetrafluoropropene (HFO-1234ze) is a non-ozone-depleting fluorocarbon replacement with a low global warming potential and is developed as foam blowing agent. The biotransformation of HFO-1234ze was investigated after inhalation exposure. Male Sprague–Dawley rats were exposed to air containing 2000; 10,000; or 50,000 ppm (n=5\\/concentration) HFO-1234ze. Male B6C3F1 mice were only exposed to 50,000 ppm HFO-1234ze. All inhalation exposures were conducted for 6 h in

Paul Schuster; Ruediger Bertermann; George M. Rusch; Wolfgang Dekant

2009-01-01

412

Atomic Chlorine and the Chlorine Monoxide Radical in the Stratosphere: Three in situ Observations.  

PubMed

Three simultaneous observations of atomic chlorine (Cl) and the chlorine monoxide radical (ClO) are reported which encompass the altitude interval between 25 and 45 kilometers. Together, Cl and ClO form a gas-phase catalytic cycle potentially capable of depleting stratospheric ozone. Observed Cl and C1O densities, although variable, imply that chlorine compounds constitute an important part of the stratospheric ozone budget. The results are compared with recent models of stratospheric photochemistry which have been used as a basis for predicting ozone depletion resulting from fluorocarbon release. PMID:17842135

Anderson, J G; Margitan, J J; Stedman, D H

1977-11-01

413

Glycosyl-nucleolipids as new bioinspired amphiphiles.  

PubMed

Four new Glycosyl-NucleoLipid (GNL) analogs featuring either a single fluorocarbon or double hydrocarbon chains were synthesized in good yields from azido thymidine as starting material. Physicochemical studies (surface tension measurements, differential scanning calorimetry) indicate that hydroxybutanamide-based GNLs feature endothermic phase transition temperatures like the previously reported double chain glycerol-based GNLs. The second generation of GNFs featuring a free nucleobase reported here presents a better surface activity (lower glim) compared to the first generation of GNFs. PMID:24084025

Latxague, Laurent; Patwa, Amit; Amigues, Eric; Barthélémy, Philippe

2013-09-30

414

Weak-value thermostat with 0.2 mK precision.  

PubMed

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. PMID:23202114

Egan, Patrick; Stone, Jack A

2012-12-01

415

Determination of charge heterogeneity and level of unconjugated antibody by imaged cIEF.  

PubMed

Imaged capillary isoelectric focusing (icIEF) is capable of monitoring the charge heterogeneity profile of conjugated antibodies. The electropherogram from icIEF can be integrated to quantitate the amount of unconjugated antibody present in a conjugate sample. This chapter describes an icIEF method where a conjugate sample was first prepared by mixing with appropriate ampholytes, pI markers, and additives. Then, the sample was focused in a fluorocarbon-coated fused silica capillary, where absorbance images were taken. Quantitation of the unconjugated antibody was achieved by using a calibration curve. PMID:23913156

Lin, Joyce; Lazar, Alexandru C

2013-01-01

416

Development of a high-tensile-strain plastic-bonded TATB explosive  

SciTech Connect

Typical plastic-bonded explosives (PBX) with greater than 90 weight-percent explosive filler in a fluorocarbon binder have tensile strains which range from 0.2 to 0.6{percent}. We have recently developed a TATB-based PBX with a tensile strain approaching 1{percent} while maintaining a high-volume loading of the crystalline explosive component. We discuss our formulation efforts to design a TATB/poly(styrene-(ethylene-butylene)-styrene)(Kraton){sup 1} PBX and the critical processing parameters which affect the ultimate mechanical properties of this PBX. 9 refs., 3 figs., 5 tabs.

Pruneda, C.; McGuire, R.; Clements, R.

1990-04-05

417

Measurements of the surface tension of three refrigerants, R 22, R 115, and R 502  

SciTech Connect

The surface tension was measured on three fluorocarbon refrigerants, R 22 (chlorodifluoromethane, CHCLF/sub 2/), R 115 (chloropentafluoroethane, CCLF/sub 2/CF/sub 3/), and R 502 (azeotropic mixture of 48.9 wt % R 22 and 51.1 wt % R 115), by using the capillary rise method. The results cover the range of temperatures from 273 K to a temperature close to the critical point of each substance. The uncertainty of surface tension measurements was estimated to be less than +-0.16 mN/m. For R 115 and R 502, van der Waals type correlations were developed based on the present results.

Okada, M.; Arima, T.; Hattori, M.; Watanabe, K.

1988-10-01

418

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

PubMed

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

Johnston, D A

1980-07-25

419

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

SciTech Connect

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

Johnston, D.A.

1980-07-25

420

Solubilities of krypton and xenon in dichlorodifluoromethane  

SciTech Connect

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.

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

1984-07-01

421

Low-noise polymeric nanomechanical biosensors  

NASA Astrophysics Data System (ADS)

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 1 mN/m.

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

2006-03-01

422

Evaluation of metallic foils for preconcentration of sulfur-containing gases with subsequent flash desorption/flame photometric detection  

SciTech Connect

Ag, Ni, Pd, Pt, Rh, and W foils were examined for their collective efficiencies toward seven sulfur-containing gases, i.e., H/sub 2/S, CH/sub 3/SH, CH/sub 3/SCH/sub 3/, CH/sub 3/SSCH/sub 3/, CS/sub 2/, COS, and SO/sub 2/. Low- and sub-part-per-billion (v/v) concentrations of these individual sulfur gases in air were drawn through a fluorocarbon resin cell containing a mounted 30-mm x 7-mm x 0.025-mm metal foil. The preconcentrated species were then thermally desorbed by a controlled pulse of current through the foil. The desorbed sample plug was swept in precleaned zero air from the fluorocarbon resin cell to a flame photometric detector. Sampling flow rate, ambient temperature, sample humidity, and common oxidants were examined for their effects on the collection efficiencies of these sulfur compounds on platinum and palladium foils. Analytical characteristics of this metal foil collection/flash desorption/flame photometric detector (MFC/FD/FPD) technique include a sulfur gas detectability of less than 50 pptr (parts per trillion) (v/v), a response repeatability of at least 95%, and field portable collection cells and instrumentation. The results are discussed both in terms of potential analytical applications of MFC/FD/FPD and in terms of their relationship to characterized models of gas adsorption on solid surfaces. 33 references, 6 figures, 3 tables.

Kagel, R.A.; Farwell, S.O.

1986-05-01

423

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

NASA Astrophysics Data System (ADS)

12 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.

Yabe, Akira; Niino, Hiroyuki; Wang, Jun

2001-01-01

424

Designing novel hybrid materials by one-pot co-condensation: from hydrophobic mesoporous silica nanoparticles to superamphiphobic cotton textiles.  

PubMed

This work reports the synthesis and characterization of mesoporous silica nanoparticles (MSNs) functionalized with tridecafluorooctyltriethoxysilane (F13) and their in situ incorporation onto cotton textiles. The hybrid MSNs and the functional textiles were prepared by a one-pot co-condensation methodology between tetraethylorthosilicate (TEOS) and F13, with hexadecyltrimethylammonium chloride (CTAC) as the template and triethanolamine as the base. The influence of the F13 to TEOS molar ratio (1:10, 1:5 and 1:3) on the nanoparticle morphology, porosity, degree of functionalization, and hydro/oleophobic properties is discussed. The hybrid nanosilicas presented high colloidal stability and were spherical and monodispersed with average particle size of ?45 nm. They also showed high surface areas, large pore volumes, and a wormhole-type mesoporous structure. The increase in the organosilane proportion during the co-condensation process led to a more radially branched wormhole-like mesoporosity, a decrease in the surface area, pore volume, and amount of surface silanol groups, and an enrichment of the surface with fluorocarbon moieties. These changes imparted hydrophobic and oleophobic properties to the materials, especially to that containing the highest F13 loading. Cotton textiles were coated with the F13-MSNs through an efficient and less time-consuming route. The combination between surface roughness and mesoporosity imparted by the MSNs, and the low surface energy provided by the organosilane resulted in superhydrophobic functional textiles. Moreover, the textile with the highest loading of fluorocarbon groups was superamphiphobic. PMID:21615151

Pereira, C; Alves, C; Monteiro, A; Magén, C; Pereira, A M; Ibarra, A; Ibarra, M R; Tavares, P B; Araújo, J P; Blanco, G; Pintado, J M; Carvalho, A P; Pires, J; Pereira, M F R; Freire, C

2011-06-10

425

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

PubMed

Ordered, hierarchical (triple-scale), superhydrophobic, oleophobic, superoleophobic, and amphiphilic surfaces on poly(methyl methacrylate) PMMA polymer substrates are fabricated using polystyrene (PS) microparticle colloidal lithography, followed by oxygen plasma etching-nanotexturing (for amphiphilic surfaces) and optional subsequent fluorocarbon plasma deposition (for amphiphobic surfaces). The PS colloidal microparticles were assembled by spin-coating. After etching/nanotexturing, the PMMA plates are amphiphilic and exhibit hierarchical (triple-scale) roughness with microscale ordered columns, and dual-scale (hundred nano/ten nano meter) nanoscale texture on the particles (top of the column) and on the etched PMMA surface. The spacing, diameter, height, and reentrant profile of the microcolumns are controlled with the etching process. Following the design requirements for superamphiphobic surfaces, we demonstrate enhancement of both hydrophobicity and oleophobicity as a result of hierarchical (triple-scale) and re-entrant topography. After fluorocarbon film deposition, we demonstrate superhydrophobic surfaces (contact angle for water 168°, compared to 110° for a flat surface), as well as superoleophobic surfaces (153° for diiodomethane, compared to 80° for a flat surface). PMID:21351799

Ellinas, K; Tserepi, A; Gogolides, E

2011-02-25

426

A sealed preparation for long-term observations of cultured cells.  

PubMed

INTRODUCTIONThe continuous long-term observation of cultured cells on the microscope has always been a technically demanding undertaking. This protocol describes a sealed preparation that allows the continuous long-term observation of cultured mammalian cells on upright or inverted microscopes without environmental CO(2) control. The preparation allows for optical conditions consistent with high-quality imaging and good cell viability for at least 100 hours. The preparation is an aluminum support slide with a square aperture cut in its center. The coverslip bearing the cells is attached to the top of the slide with a thin layer of silicone grease, and the bottom of the slide is similarly covered with a clean coverslip of the same size. The thickness of the slide is intended to coordinately maximize the volume of the medium while maintaining optical properties that allow Koehler illumination with standard condensers. The chamber is filled in equal parts with HEPES-buffered media containing fetal calf serum and a low-viscosity fluorocarbon oil. These oils have a high solubility for atmospheric gases. The inclusion of the oil in the preparations is intended to provide a source of oxygen and perhaps a sink for some of the CO(2) produced by the cells. Although the inclusion of fluorocarbon oil in the preparation may not be necessary for short-term (~24 hr) observations, particularly with cells that are sparsely plated, long-term cell viability is ensured when the oil is present. PMID:21356931

Sluder, Greenfield; Nordberg, Joshua J; Miller, Frederick J; Hinchcliffe, Edward H

2007-01-01

427

Non-contact protein microarray fabrication using a procedure based on liquid bridge formation.  

PubMed

Contemporary microarrayers of contact or non-contact format used in protein microarray fabrication still suffer from a number of problems, e.g. generation of satellite spots, inhomogeneous spots, misplaced or even absent spots, and sample carryover. In this paper, a new concept of non-contact sample deposition that reduces such problems is introduced. To show the potential and robustness of this pressure-assisted deposition technique, different sample solutions known to cause severe problems or to be even impossible to print with conventional microarrayers were accurately printed. The samples included 200 mg mL(-1) human serum albumin, highly concentrated sticky cell adhesion proteins, pure high-salt cell-lysis buffer, pure DMSO, and a suspension of 5-microm polystyrene beads. Additionally, a water-immiscible liquid fluorocarbon, which was shown not to affect the functionality of the capture molecules, was employed as a lid to reduce evaporation during microarray printing. The fluorocarbon liquid lid was shown to circumvent hydrolysis of water-sensitive activated surfaces during long-term deposition procedures. PMID:19023564

Hartmann, Michael; Sjödahl, Johan; Stjernström, Mårten; Redeby, Johan; Joos, Thomas; Roeraade, Johan

2008-11-21

428

Perfluorocompounds (PFCs) Abatement System Utilizing Fluorine Immobilized Adsorbent  

NASA Astrophysics Data System (ADS)

In order to minimize contributions to global warming, it is important to develop a Perfluorocompounds (PFCs) abatement system that can remove PFCs effectively with low electric power. We have developed a new PFCs abatement system consisting mainly of a 2 MHz ICP plasma source and two CaO columns operated at low pressure. The CaO agent developed for this system has a specific surface area of 60-80 m2/g and a grain diameter of 2-6 mm, simultaneously. Reactive fluorinated compounds are immobilized in the CaO columns without a water scrubber to prevent the recombination of fluorocarbons. Stable compounds such as CF4 are decomposed by the 2 MHz ICP plasma before introducing in the second CaO column. When the emissions from a fluorocarbon film chemical vapor deposition process chamber were treated by this abatement system, PFCs removal efficiency and CO2 equivalent removal efficiency was 99.96% and 93.5%, respectively.

Suzuki, Katsumasa; Ishihara, Yoshio; Sakoda, Kaoru; Shirai, Yasuyuki; Ohmi, Tadahiro; Watanabe, Takayuki; Ito, Takashi

429

Optimization of the Properties of Carbon Nanotube-Based Structures by Electron and Ion Beam Irradiation  

NASA Astrophysics Data System (ADS)

There is considerable interest in building new nanostructures for electronic devices and incorporating nanostructured fibers and particles into composites. Here, classical molecular dynamics simulations are used to study the production of new carbon nanotube junctions or cross-links through electron irradiation, in addition to the chemical modification of carbon nanotube-based structures and composites through ion and polyatomic ion beam deposition. In particular, electron irradiation is used to produce junctions between carbon nanotubes. The specific reactions that lead to junction-formation and the mechanical and electronic properties of the resulting junctions will be discussed. Additionally, the chemical modification of multi-walled nanotubes, single-walled and multi-walled nanotube bundles, nanopeapods, and nanotube-polymer composites from polyatomic fluorocarbon ions, which are commonly present in low-energy fluorocarbon plasmas, and Ar will be presented. Multi-walled carbon nanotubes usually fail through the so-called ``sword-and-sheath'' mechanism and nanotube-polymer composites often fail through nanotube pullout. In both cases the failure mechanism is due to the weak van der Waals bonds between either the nanotube shells in the multi-walled tube or between the nanotubes and polymer matrix in the composite. The simulation results show that ion beam deposition produces cross-links between shells in multi-walled nanotubes and between otherwise unfunctionalized nanotubes and polymer backbone chains, which ultimately toughens the composites. The conditions that are predicted to be optimum for effective chemical modification of the system will be discussed.

Sinnott, Susan

2005-03-01

430

A study of the cardiac effects of bromochlorodifluoromethane (halon 1211) exposure during exercise.  

PubMed

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. PMID:1536156

Kaufman, J D; Morgan, M S; Marks, M L; Greene, H L; Rosenstock, L

1992-01-01

431

Correlating linactant efficiency and self-assembly: structural basis of line activity in molecular monolayers.  

PubMed

Surfactants exhibit characteristic phenomena, including the reduction of interfacial free energy, self-assembly into aggregates, and even the formation of lyotropic liquid crystalline phases at high concentrations. Our research has shown that a semifluorinated phosphonic acid can act as the two-dimensional analogue of a surfactant-a linactant-by reducing the line tension between hydrocarbon-rich and fluorocarbon-rich phases in a Langmuir monolayer. This linactant can also self-assemble into nanoscale clusters in a monolayer. Here, we explore the dependence of linactant behavior on molecular structure. Members of a homologous series of partially fluorinated phosphonic acids were synthesized and tested as linactants: CF(3)(CF(2))(n-1)(CH(2))(m)PO(3)H (abbreviated as FnHmPO(3)). The tests revealed that linactants with longer hydrophobic chains were most efficient in lowering line tension. For linactants with the same overall chain length, the length of the fluorocarbon block was correlated with efficiency. Thus, the linactant efficiency was ranked in the order F8H8PO(3) < F10H6PO(3) < F8H11PO(3) < F10H9PO(3). In all cases, linactant-containing Langmuir-Blodgett monolayers exhibited nanoscale molecular clusters with characteristic dimensions of 20-30 nm; enhanced linactant efficiency was systematically correlated with larger clusters. PMID:19594183

Trabelsi, Siwar; Zhang, Zhongcheng; Zhang, Shishan; Lee, T Randall; Schwartz, Daniel K

2009-07-21

432

Line tension and line activity in mixed monolayers composed of aliphatic and terphenyl-containing surfactants.  

PubMed

Custom-designed surfactants, known as "linactants", have the ability to reduce the line tension between coexisting phases within mixed monolayers of chemically dissimilar compounds at the air-water interface. Thus far, linactants have been successfully identified for only one type of chemical dissimilarity, involving mixed monolayers of hydrocarbon and fluorocarbon surfactants. In the present work, we have pursued a more general interpretation of linactant compounds by extending the concept to a new system that is comprised of a mixture of aliphatic (pentadecanoic acid) and aromatic (p-terphenyl carboxylic acid) compounds. We found that the "bare" line tension between phases of this mixed monolayer was ~4 pN, and within the same order of magnitude as our previous measurement in mixed monolayers containing hydrocarbons and fluorocarbons. Furthermore, we examined a homologous series of potential linactant compounds possessing an aliphatic tail of variable length and a p-terphenyl block. We determined that linactants with longer tails were able to reduce the line tension more efficiently and effectively. In particular, the addition of only 0.14% of a linactant with an 11-carbon chain reduced the line tension by more than a factor of 2. We hypothesize that the efficiency of this particular linactant is associated with its long tail; this creates strong van der Waals interactions with the aliphatic chains and enables the tail to adopt conformations that facilitate ?-stacking interactions with the aromatic compounds within the monolayer. PMID:23101697

Sriram, Indira; Singhana, Burapol; Lee, T Randall; Schwartz, Daniel K

2012-11-06

433

The influence of Ar addition on the structure of an a-SiOCF film prepared by plasma-enhanced chemical vapour deposition  

NASA Astrophysics Data System (ADS)

The preparation of a-SiOCF films from Si(OC2H5)4, C4F8 and/or Ar using a plasma-enhanced chemical vapour deposition method is reported. The chemical bonding structures of the films are analysed by high-resolution x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy. The results show that the films contain F-Si-O-Si, Si-OH, Si-O-Si, C-CF and C-F configurations. However, as for the film deposited from the feeding gases with Ar, a C-C configuration is also included in addition to the above-mentioned configurations. This indicates that the existence of Ar in the plasma leads to the formation of a fluorocarbon structure with a high degree of cross-linking. No evidence reveals the presence of a Si-C bond in the film, so it is believed that the fluorocarbon is perhaps embedded into the matrix of SiOF.

Ding, Shi-Jin; Wang, Peng-Fei; Zhang, David Wei; Wang, Ji-Tao; Lee, Wei William

2001-01-01

434

Fluorinated microemulsions: A study of the phase behavior and structure  

SciTech Connect

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.

LoNostro, P. [Univ. of Florence, Firenze (Italy). Dept. of Chemistry; Choi, S.M.; Chen, S.H. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Nuclear Engineering; Ku, C.Y. [Argonne National Lab., IL (United States)

1999-06-24

435

Removal of Fluoropolimers from the Surface of Silicon Structures by Treatment in an Atomic Hydrogen Flow  

SciTech Connect

The possibility of successful removal of fluoropolimers from the surface of silicon structures by treatment in an atomic hydrogen flow is investigated. It is ascertained that the treatment of samples in a direct atomic hydrogen flow with a density of 2 x 10{sup 15} cm{sup -2} s{sup -1} at temperatures from 20 to 100 deg. C leads to a decrease in the content of fluorocarbon residues (in particular, CF) by 5 orders of magnitude. Fluorocarbon residues are removed from both the planar surface of silicon structures and the lateral walls and the bottom of contact holes with a diameter of 0.3-0.25 {mu}m and larger and a depth of 0.9 {mu}m, opened in a SiO{sub 2} layer by reactive ion etching. A treatment time of 2 min is sufficient for complete removal of the fluoropolimers. This process of dry cleaning can be recommended for use in the fabrication of integrated circuits containing an interlayer of a low-permittivity insulator.

Anishchenko, E.V.; Kagadei, V.A. [Research Institute of Semiconductor Devices, ul. Krasnoarmeiskaya 99a, Tomsk, 634034 (Russian Federation); Nefedtsev, E.V.; Proskurovskii, D.I.; Romanenko, S.V. [Institute of High-Current Electronics, Siberian Division, Russian Academy of Sciences, Akademicheskii pr. 4, Tomsk, 634021 (Russian Federation)

2005-11-15

436

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

PubMed

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

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

1990-04-01

437

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

NASA Astrophysics Data System (ADS)

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.

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

1984-11-01

438

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

NASA Astrophysics Data System (ADS)

This paper reports a small angle neutron scattering investigation of micelle formation by fluorocarbon-hydrocarbon block copolymers in supercritical CO2(sc-CO2) at 65 °C. A sharp unimer-micelle transition is obtained due to the tuning of the solvating ability of sc-CO2 by profiling pressure, so that the block copolymer, in a semidilute solution, finds sc-CO2 a good solvent at high pressure and a poor solvent at low pressure. At high pressure the copolymer is in a monomeric state with a random coil structure. However, on lowering the pressure, aggregates are formed with a structure similar to aqueous micelles with the hydrocarbon segments forming the core and the fluorocarbon segments forming the corona of the micelle. This unimer-aggregate transition is driven by the gradual elimination of CO2 molecules solvating the hydrocarbon segments of the polymer. Comparison of these results with related data on the same polymer at different temperatures indicates that the transition is critically related to the density of the solvent. This suggests the definition of a critical micellization density, to our knowledge a new concept in colloid chemistry.

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

2000-04-01

439

Electron attachment to radicals and other reactive molecules  

NASA Astrophysics Data System (ADS)

Electron attachment to highly reactive fluorocarbon species C2F5 and CF2 has been studied experimentally with a TEM-TOF apparatus (TEM- Trochoidal Electron Monochrator; TOF - Time-of-Flight mass spectrometer; Field et al., J. Phys. B 38 (2005) 255). These reactive molecules have been generated in situ by fast atom reactions and by passing fluorocarbon precursors through a microwave discharge. In the case of C2F5 low energy electron attachment is observed with the formation of F^- at close to zero electron energy, however, no electron attachment to CF2 was observed, despite theoretical prediction of a significant dissociative electron attachment cross section (Rozum et al., J. Phys. Chem. Ref. Data 35 (2006) 267). An upper limit for the dissociative electron attachment cross section of CF2 has been estimated as 5x10-4 å^2 at 1.8 eV, which is the thermodynamic threshold for F^- formation from CF2. (Graupner et al., New J. Phys. 12 (2010) 083035).[4pt] Work done in collaboration with Karola Graupner and Sean Haughey, Centre for Plasma Physics, Queens University, Belfast; Christopher Mayhew, Dept. Physics, University of Birmingham, UK; and Judith Langer, Institut fur Optik und Atomare Physik, TU Berlin, Germany.

Field, Tom

2011-11-01

440

Uv protective coatings for heliostats and the plastic dome. Final technical report  

SciTech Connect

Fluorocarbon and acrylic coatings and films were explored as a means of preventing uv degradation of: (1) the polyester (Petra A) film used in the heliostat dome, (2) the first surface silvered polyester (Melinex O) heliostat, (3) the first surface silvered float glass heliostat, as well as (4) and with other coatings to prevent silver spotting of the back surface of a superstrate, second surface heliostat mirror. Uv stabilization systems were developed and tested. The coated or laminated structures were evaluated for adhesion, resistance to high humidity and acid vapor degradation, percent transmittance/ reflectance, water spotting (for case 4 above), and uv stability under the RS-4 Sunlamp (wet and dry). Promising materials were subjected to accelerated outdoor exposure at Desert Sunshine Testing (DSET) in Arizona. Specific uv stabilized acrylic coatings and/or acrylic or fluorocarbon films offered some protection for the Petra A, silvered Melinex O and first surface silvered float glass against weathering, or in case 4 moisture, degradation. However, no system was satisfactory for long term outdoor weathering. Phenoxy primers showed initial promise for back surface protection against silver spotting but require further in depth study.

Baum, B.; Bansleben, E.; McGrath, P.

1981-11-01

441

Strong resistance of (tridecafluoro-1,1,2,2-tetrahydrooctyl)triethoxysilane (TTS) nanofilm to protein adsorption.  

PubMed

In this report, the properties of fluorocarbon-containing (tridecafluoro-1,1,2,2-tetrahydrooctyl)triethoxysilane (TTS) (C14 H19 F13 O3 Si) nanofilm coated on silicon surface and its potential to resist protein adsorption were examined. Thickness and wettability of the silicon surface before and after TTS nanofilm coating were examined by ellipsometry and contact angle goniometry, respectively. The same techniques were used to examine protein layer on nonmodified and TTS-coated silicon surface. In addition, bright-field optical microscopy and fluorescence spectrophotometry were used to provide visual, qualitative description of adsorbed proteins and the specific signal of fluorescence-labeled bovine serum albumin (BSA), respectively, on bare and TTS-coated silicon surface. Single-component protein solution of four model proteins, namely BSA, human fibrinogen, bovine serum immunoglobulin G, and fibronectin, was prepared, and the adsorption responses of these four proteins on TTS nanofilm were examined, using nonmodified silicon surface as comparison. TTS substantially reduces the adsorption of all four proteins tested. Our results indicate that fluorocarbon-containing TTS, once coated on surfaces, is an effective molecule for resisting protein adsorption. This will open up potential applications, particularly for silicon-containing implant devices such as glass. PMID:23826851

Alluri, Chandrakanth; Ji, Hai-Feng; Sit, Pingfai Sidney

2013-10-08

442

Creation of superhydrophobic stainless steel surfaces by acid treatments and hydrophobic film deposition.  

PubMed

In this work, we present a method to render stainless steel surfaces superhydrophobic while maintaining their corrosion resistance. Creation of surface roughness on 304 and 316 grade stainless steels was performed using a hydrofluoric acid bath. New insight into the etch process is developed through a detailed analysis of the chemical and physical changes that occur on the stainless steel surfaces. As a result of intergranular corrosion, along with metallic oxide and fluoride redeposition, surface roughness was generated on the nano- and microscales. Differences in alloy composition between 304 and 316 grades of stainless steel led to variations in etch rate and different levels of surface roughness for similar etch times. After fluorocarbon film deposition to lower the surface energy, etched samples of 304 and 316 stainless steel displayed maximum static water contact angles of 159.9 and 146.6°, respectively. However, etching in HF also caused both grades of stainless steel to be susceptible to corrosion. By passivating the HF-etched samples in a nitric acid bath, the corrosion resistant properties of stainless steels were recovered. When a three step process was used, consisting of etching, passivation and fluorocarbon deposition, 304 and 316 stainless steel samples exhibited maximum contact angles of 157.3 and 134.9°, respectively, while maintaining corrosion resistance. PMID:22913317

Li, Lester; Breedveld, Victor; Hess, Dennis W

2012-08-31

443

Highly reproducible chronoamperometric analysis in microdroplets.  

PubMed

Here we report a method for highly reproducible chronoamperometric analysis of the contents of microdroplets. Aqueous microdroplets having volumes on the order of 1 nL and separated by a fluorocarbon solvent are generated within a microfluidic device using a T-shaped junction. The key finding is that stable and reproducible quasi-steady-state currents are observed if the electrochemical measurements are made in a narrowed segment of a microchannel. Under these conditions, the microdroplets are stretched, here by a factor of 10, leading to desirable intradroplet mass transfer characteristics. Microdroplet frequencies up to 0.67 s(-1) are accessible using this method. The quasi-steady-state currents resulting from chronoamperometric analysis of microdroplets containing 1.0 mM Ru(NH3)6(3+) have relative standard deviations of just 1.8% and 2.8% at flow rates of 30 nL min(-1) and 60 nL min(-1), respectively. Importantly, the design of the microelectrochemical device ensures direct contact between intradroplet redox molecules and the electrode surface. That is, the fluorocarbon between microdroplets does interfere with inner-sphere electrocatalytic processes such as the oxygen reduction reaction. Finite-element simulations are presented that are in accord with the experimental findings. PMID:23386119

Liu, Hong; Crooks, Richard M

2013-04-01

444

Amphiphilic crescent-moon-shaped microparticles formed by selective adsorption of colloids.  

PubMed

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 (?) shape that injects two oil phases into water in a single receiving capillary. One oil is a fluorocarbon, while the second is a photocurable monomer, which partially wets the first oil drop; silica colloids in the monomer migrate and adsorb to the interface with water but do not protrude into the oil interface. Upon UV-induced polymerization, solid particles with the shape of a crescent moon are formed; removal of fluorocarbon oil yields amphiphilic particles due to the selective adsorption of silica colloids. The resultant amphiphilic microparticles can be used to stabilize oil drops in a mixture of water and ethanol; if they are packed to sufficient surface density on the interface of the oil drop, they become immobilized, preventing direct contact between neighboring drops, thereby providing the stability. PMID:21417254

Kim, Shin-Hyun; Abbaspourrad, Alireza; Weitz, David A

2011-03-21

445

A micro-spectroscopy study on the influence of chemical residues from nanofabrication on the nitridation chemistry of Al nanopatterns  

NASA Astrophysics Data System (ADS)

We applied spatially resolved photoelectron spectroscopy implemented with an X-ray photoemission electron microscopy (XPEEM) using soft X-ray synchrotron radiation to identify the compositional and morphological inhomogeneities of a SiO2/Si substrate surface nanopatterned with Al before and after nitridation. The nanofabrication was conducted by a polymethylmethacrylate (PMMA)-based e-beam lithography and a fluorine-based reactive ion etching (RIE), followed by Al metalization and acetone lift-off. Three types of chemical residues were identified before nitridation: (1) fluorocarbons produced and accumulated mainly during RIE process on the sidewalls of the nanopatterns; (2) a thick Al-bearing PMMA layer and/or (3) a thin PMMA residue layer owing to unsuccessful or partial lift-off of the e-beam unexposed PMMA between the nanopatterns. The fluorocarbons actively influenced the surface chemical composition of the nanopatterns by forming AlF compounds. After nitridation, in the PMMA residue-free area, the AlF compounds on the sidewalls were decomposed and transformed to AlN. The PMMA residues between the nanopatterns had no obvious influence on the surface chemical composition and nitridation properties of the Al nanopatterns. They were only partially decomposed by the nitridation. The regional surface morphology of the nanopatterns revealed by the secondary electron XPEEM was consistent with the scanning electron microscopy results.

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

2012-03-01

446

A study of the cardiac effects of bromochlorodifluoromethane (halon 1211) exposure during exercise  

SciTech Connect

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.

Kaufman, J.D.; Morgan, M.S.; Marks, M.L.; Greene, H.L.; Rosenstock, L. (Department of Medicine, University of Washington, Seattle (United States))

1992-01-01

447

Cardiotoxicity of Freon among refrigeration services workers: comparative cross-sectional study  

PubMed Central

Background Freon includes a number of gaseous, colorless chlorofluorocarbons. Although freon is generally considered to be a fluorocarbon of relatively low toxicity; significantly detrimental effects may occur upon over exposure. The purpose of the present study is to investigate whether occupational exposure to fluorocarbons can induce arterial hypertension, myocardial ischemia, cardiac arrhythmias, elevated levels of plasma lipids and renal dysfunction. Methods This comparative cross-sectional study was conducted at the cardiology clinic of the Suez Canal Authority Hospital (Egypt). The study included 23 apparently healthy male workers at the refrigeration services workshop who were exposed to fluorocarbons (FC 12 and FC 22) and 23 likewise apparently healthy male workers (unexposed), the control group. All the participants were interviewed using a pre-composed questionnaire and were subjected to a clinical examination and relevant laboratory investigations. Results There were no significant statistical differences between the groups studied regarding symptoms suggesting arterial hypertension and renal affection, although a significantly higher percentage of the studied refrigeration services workers had symptoms of arrhythmias. None of the workers had symptoms suggesting coronary artery disease. Clinical examination revealed that the refrigeration services workers had a significantly higher mean pulse rate compared to the controls, though no significant statistical differences were found in arterial blood pressure measurements between the two study groups. Exercise stress testing of the workers studied revealed normal heart reaction to the increased need for oxygen, while sinus tachycardia was detected in all the participants. The results of Holter monitoring revealed significant differences within subject and group regarding the number of abnormal beats detected throughout the day of monitoring (p < 0.001). There were no significant differences detected in the average heart rate during the monitoring period within subject or group. Most laboratory investigations revealed absence of significant statistical differences for lipid profile markers, serum electrolyte levels and glomerular lesion markers between the groups except for cholesterol and urinary ?2-microglobulin (tubular lesion markers) levels which were significantly elevated in freon exposed workers. Conclusions Unprotected occupational exposure to chlorofluorocarbons can induce cardiotoxicity in the form of cardiac arrhythmias. The role of chlorofluorocarbons in inducing arterial hypertension and coronary artery diseases is unclear, although significantly elevated serum cholesterol and urinary ?2-microglobulin levels raise a concern.

2009-01-01

448

Control of atomic layer degradation on Si substrate  

SciTech Connect

To develop 32 nm node devices, the degradation of atomic layers on the surface of Si substrates must be controlled. During the etching of a SiO{sub 2} or Si{sub 3}N{sub 4} hard mask or sidewall, the surface of Si is attended due to exposure to fluorocarbon plasma. The authors have quantitatively evaluated the relationship between the energy of incident ions and the thickness of the fluorocarbon polymer for a CH{sub 2}F{sub 2}/CF{sub 4}/Ar/O{sub 2} plasma in a dual frequency CCP system. At a fixed ion energy the thickness of the damage layer (T{sub d}) basically depended on the thickness of the fluorocarbon polymer (T{sub C-F}). When the T{sub C-F} was changed by controlling the O/CF{sub x} gas ratio, T{sub d} had a minimum thickness under the conditions at balance point: P{sub b}, under which the T{sub C-F} was nearly equal to ion penetration depth: D{sub p}. Using molecular dynamics simulation, reaction around the transition from SiO{sub 2} to Si was clarified. The damage was done to the Si before the SiO{sub 2} was completely removed, and the largest T{sub d} was observed when the SiO{sub 2} was etched off. After that, T{sub C-F} began to increase because there was no longer an outflux of O from SiO{sub 2} and the damage decreased as the unstable SiF{sub x} species in the damaged layer desorbed. Once the T{sub C-F} became thicker than the ion penetration depth, the damaged layer got buried and T{sub d} stopped changing. When the ion penetration depth was controlled to be equal to T{sub C-F} in a steady state under low ion energy conditions, the T{sub d} was reduced to less than 1 nm.

Nakamura, Y.; Tatsumi, T.; Kobayashi, S.; Kugimiya, K.; Harano, T.; Ando, A.; Kawase, T.; Hamaguchi, S.; Iseda, S. [LSI Production Division 1, Sony Semiconductor Kyushu Corp., 1883-43 Tsukuba-machi, Isahaya-shi, Nagasaki 854-0065 (Japan); Semiconductor Technology Development Division, Sony Corp., 4-14-1 Asahi-cho, Atsugi-shi, Kanagawa 243-0014 (Japan); LSI Production Division 1, Sony Semiconductor Kyushu Corp., 1883-43 Tsukuba-machi, Isahaya-shi, Nagasaki 854-0065 (Japan); Semiconductor Technology Development Division, Sony Corp., 4-14-1 Asahi-cho, Atsugi-shi, Kanagawa 243-0014 (Japan); Center for Atomic and Molecular Technologies, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); LSI Production Division 1, Sony Semiconductor Kyushu Corp., 1883-43 Tsukuba-machi, Isahaya-shi, Nagasaki 854-0065 (Japan)

2007-07-15

449

Diode Laser Spectroscopy for Manufacturing Process and Environmental Monitoring.  

NASA Astrophysics Data System (ADS)

Diode laser infrared absorption spectroscopy using tunable lead-salt and GaAlAs laser diodes was developed for manufacturing process and environmental monitoring. Intermediate and reaction product species formed from discharge of rm C_2F_6, CHF_3 were studied in real-time with a processing plasma chamber for microelectronics fabrication. For the intermediate CF_2 radical, a typical line strength of 3.36 ^{*} 10^ {-20}cm/molecule of the v_3 band provides a minimum detectable partial pressure of 4 muTorr. Both capacitively and inductively coupled plasma source configurations were used. It was found that for the capacitively-coupled source, the primary source gas consumption ratio was almost independent of the initial concentration of the source gas. The generation of CF_2 from rm C _2F_6 was related to the residence time of the source gas inside the discharge region. Etching of poly-Si/SiO_2/Si was studied with all inductively coupled plasma source. Concentration of the etching product SiF_4 was monitored with various primary source gases during the reaction. Significant change in concentration was observed from SF_6 discharge upon termination of SiO_2 etching but was much reduced for fluorocarbon source gases such as rm C_2F_6 and CHF_3. In addition, a prominent low frequency periodic variation in the SiF_4 was also observed. The small change in SiF_4 concentration for the fluorocarbon plasmas is due to the chemically preferred etching of SiO_2 combined with the high atomic density of Si atoms in the Si layer. These results suggest that for etching with fluorocarbon plasmas, endpoint detection with the nu_5 band of COF_2 near 1250 cm^{-1} would be more sensitive. The technique was also used to detect NO _2 and trichloroethylene. The minimum detectable concentration of NO_2 was 364 ppb at 85 Torr total pressure in a 1 Hz bandwidth and 10 inches absorption length and was found to be strongly pressure dependent due to the broadening of absorption profile. Finally, a miniaturized oxygen detection system based on commercially available GaAlAs diode lasers was developed. A system stability of less than 0.5% fluctuation in absorption signal was achieved.

Ng, Chi Kong

450

Synthesis of new high performance lubricants and solid lubricants  

SciTech Connect

In our second year of funding we began the testing phase of a number of new classes of lubricants. Three different testing collaborations have already begun and a fourth one is In the works with Dr. Stephen Hsu of the National Institute of Standards and Technology. Dr. Hsu also plans to test some of the same materials for us that Shell Development is studying. With Dr. Bill Jones of NASA, we are studying the effects of branching an high temperature lubricant properties in perfluoropolyethers, Initially Bill Jones is comparing the lubrication and physical properties of perfluorotetraglyme and the following two spherical perfluoropolyethers, Note that one contains a fluorocarbon chain and the other one contains a fluorocarbon ether chain. The synthesis of these was reported in the last progress report. With Professor Patricia Thiel of Iowa State University, we are working on studies of perfluoromethylene oxide ethers and have prepared a series of four of these polyethers to study in collaboration with her research group. These perfluoromethylene oxide ethers have the best low temperature properties of any known lubricants. Thiel's group is studying their interactions with metals under extreme conditions. Thirdly, we have also begun an Interaction with W. August Birke of Shell Development Company in Houston for whom we have already prepared samples of the chlorine-substituted fluorocarbon polyether lubricants whose structures appear on page 54 of our research proposal. Each of these four structures is thought to have potential as lubricant additives to motor oils. We also have underway syntheses of other fluorine-containing branched ether lubricants. These new materials which are also promising as antifriction additives for motor oils appear ahead of the perfluoro additives as Appendix I to the progress report. Additionally for Birke and Shell Development we have at their request prepared the novel compound perfluoro salicylic acid. This synthesis was suggested by the Shell staff who thought that esters of perfluoro salicylic acid might be an excellent antifriction additive for motor oil fuels. One of the best additives currently used in motor oils is the hydrocarbon ester of salicylic acid.

Lagow, Richard J.

1993-04-08

451

Plasma-surface interactions of nanoporous silica during plasma-based pattern transfer using C{sub 4}F{sub 8} and C{sub 4}F{sub 8}/Ar gas mixtures  

SciTech Connect

We have investigated plasma surface interactions of nanoporous silica (NPS) films with porosities up to 50%, and SiO{sub 2} with C{sub 4}F{sub 8}/Ar discharges used for plasma etching. The pore size was about 2-3 nm for all films. In highly polymerizing plasmas (e.g., pure C{sub 4}F{sub 8} discharges), the porous structure of NPS material favors surface polymerization over etching and porosity-corrected etching rates (CER) were suppressed and lower than SiO{sub 2} etching rate for the same conditions. The etching rates of NPS were dramatically enhanced in ion rich discharges (e.g., C{sub 4}F{sub 8}/90%Ar) and the CER in this case is greater than the SiO{sub 2} etching rate. Both x-ray photoelectron spectroscopy (XPS) and static secondary ion mass spectroscopy (static SIMS) show that fairly thick ({approx}2-3 nm) fluorocarbon layers exist on the NPS surface during C{sub 4}F{sub 8} etching. This layer blocks the direct interaction of ions with the NPS surface and results in a low etching rate. For C{sub 4}F{sub 8}/90%Ar discharges, little fluorocarbon coverage is observed for NPS surfaces and the direct ion surface interaction is significantly enhanced, explaining the enhancement of CER. We can deduce from analysis of angular resolved XPS data that the surface of NPS materials and SiO{sub 2} remain smooth during C{sub 4}F{sub 8} etching. For C{sub 4}F{sub 8}/90%Ar etching, the NPS surfaces became rough. The surface roughening is due to angle-dependent ion etching effects. These surface models were directly verified by the transmission electron microscopy. Depth profiling study of NPS partially etched using C{sub 4}F{sub 8} or C{sub 4}F{sub 8}/90%Ar discharges using dynamic SIMS indicates that the plasma induced modification of NPS was enhanced significantly compared with SiO{sub 2} due to the porous structure, which allows the plasma attack of the subsurface region. The modified layer thickness is related to the overall porosity and dramatically increases for NPS with an overall porosity of 50%. The distinct etching behavior of high porosity NPS ({approx}50%) in fluorocarbon-based discharges relative to NPS material with lower overall porosity is possibly due to interconnected pores, which allow plasma species to more easily penetrate into the subsurface region.

Hua Xuefeng; Stolz, Christian; Oehrlein, G.S.; Lazzeri, P.; Coghe, N.; Anderle, M.; Inoki, C.K.; Kuan, T.S.; Jiang, P. [Department of Physics and Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States); Department of Materials Science and Engineering and Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States); ITC-irst, Center for Scientific and Technological Research, 38050 Povo, Trento (Italy); Department of Physics, University at Albany, SUNY, Albany, New York 12222 (United States); Texas Instruments, Inc., Dallas, Texas 75243 (United States)

2005-01-01

452

Sensitive, high throughput detection of proteins in individual, surfactant-stabilized picoliter droplets using nanoelectrospray ionization mass spectrometry.  

PubMed

Droplet-based fluidics is emerging as a powerful platform for single cell analysis, directed evolution of enzymes, and high throughput screening studies. Due to the small amounts of compound compartmentalized in each droplet, detection has been primarily by fluorescence. To extend the range of experiments that can be carried out in droplets, we have developed the use of electrospray ionization mass spectrometry (ESI-MS) to measure femtomole quantities of proteins in individual pico- to nanoliter droplets. Surfactant-stabilized droplets containing analyte were produced in a flow-focusing droplet generation microfluidic device using fluorocarbon oil as the continuous phase. The droplets were collected off-chip for storage and reinjected into microfluidic devices prior to spraying the emulsion into an ESI mass spectrometer. Crucially, high quality mass spectra of individual droplets were obtained from emulsions containing a mixture of droplets at >150 per minute, opening up new routes to high throughput screening studies. PMID:23514243

Smith, Clive A; Li, Xin; Mize, Todd H; Sharpe, Timothy D; Graziani, Edmund I; Abell, Chris; Huck, Wilhelm T S

2013-03-27

453

Thermal conductivity of gaseous HFC-134a, HFC-143a, HCFC-141b, and HCFC-142b  

NASA Astrophysics Data System (ADS)

The thermal conductivity of new environmentally acceptable fluorocarbons HFC-134a (CH2FCF3), HFC-143a (CH3CF3), HCFC-141b (CH3CCl2F), and HCFC-142b (CH3CCl2F) in the gaseous phase has been measured in the temperature range 293 353 K at pressures up to 4 MPa. The thermal conductivity has been measured with a coaxial-cylinder cell on a relative basis. The apparatus was calibrated with He, Ne, Ar, Kr, N2, CH4, and SF6 as reference fluids. The uncertainty of the experimental data obtained is estimated to be within 2% except for the uncertainty associated with the reference thermal-conductivity values. The excess thermal conductivity has been correlated satisfactorily as a function of density.

Tanaka, Y.; Nakata, M.; Makita, T.

1991-11-01

454

Fluorinated nanocarbons using fluorinating agent: Strategies of fluorination and applications  

NASA Astrophysics Data System (ADS)

The fluorination method strongly influences the physical properties of the resulting fluorinated carbon materials. Two fluorination ways, direct fluorination under pure fluorine gas and controlled fluorination by the decomposition of TbF4, have been used for the fluorination of particular nanocarbons: carbon nanofibers and a mixture of carbon nanodiscs and nanocones. Then, fluorocarbon matrix structures have been determined owing to solid state 19F NMR for MAS conditions at a spinning speed of 30 kHz. It reveals that the fluorination mechanism depends on the fluorination conditions but not on the starting nanocarbons morphology, i.e. tubular or planar. Finally, the electrochemical properties of carbon nanofibers fluorinated by the two ways are detailed. Controlled fluorination allows an increase of the power densities of fluorinated carbon nanofibers used as electrode in primary lithium batteries.

Zhang, W.; Dubois, M.; Guérin, K.; Bonnet, P.; Kharbache, H.; Masin, F.; Thomas, P.; Mansot, J.-L.; Hamwi, A.

2010-05-01

455

Dynamic aspects of detonations; International Colloquium on Dynamics of Explosions and Reactive Systems, 13th, Nagoya, Japan, July 28-Aug. 2, 1991, Technical Papers  

NASA Astrophysics Data System (ADS)

Various papers on the dynamic aspects of detonations are presented. Individual subjects addressed include: high-resolution numerical simulations for 2D unstable detonations, simulation of cellular structure in a detonation wave, Mach reflection of detonation waves, mechanism of unstable detonation front origin, numerical modeling of galloping detonation, experimental study of the fine structure in spin detonation, influence of fluorocarbon on H2O2Ar detonation, digial signal processing analysis of soot foils, cylindrical detonations in methane-oxygen-nitrogen mixtures, structure of reaction waves behind oblique shocks, ignition in a complex Mach structure, simulations for detonation initiation behind reflected shock waves. Also discussed are: limiting tube diameter of gaseous detonation, mechanisms of detonation propagation in a porous medium propagation and extinction of detonation waves in tube bundles, structure and velocity deficit of gaseous detonation in rough tubes, possible method for quenching of a gaseous detonation, effect of hollow heterogeneities on nitromethane detonation.

Kuhl, A. L.; Leyer, J.-C.; Borisov, A. A.; Sirignano, W. A.

456

The PICASSO Dark Matter Experiment  

SciTech Connect

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.

Wichoski, Ubi [Department of Physics, Laurentian University, Sudbury, ON, P3E 2C6 (Canada); Collaboration: PICASSO Collaboration

2011-12-16

457

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

NASA Astrophysics Data System (ADS)

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 LERATM (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 LERATM station operates up to 20h a day, 6 days a week and nearly every week of the year. The tubing walls are 1-2mm thick and the outer layer is nylon and the inner 0.2mm thick layer is ethylene-tetrafluroethylene.

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

1999-02-01

458

Development of laser spectroscopic diagnostics to support advanced compound semiconductor deposition techniques  

NASA Astrophysics Data System (ADS)

This program constructed and demonstrated an apparatus for the development of laser diagnostics for the gas phase molecules involved in semiconductor fabrication techniques, particularly the organometallic chemical vapor deposition of compound semiconductors like gallium arsenide. Work on this apparatus, a flow tube with mirrors for long path tunable infrared diode laser absorption and electrodes for a radio frequency glow discharge, culminated in observations designed to assess the importance of arsenic hydride radicals in the decomposition of organoarsenic compounds. Preliminary observations of fluorocarbon and methane plasmas produced observations of several species which could be compared with models and other observations and which added to knowledge of these systems with their important applications in silicon etching an diamond deposition. The program also resulted in band strength measurements for the methyl and difluorocarbene radicals, using tunable diode laser, dye laser, and fast flow reactor techniques.

Wormhoudt, Joda C.

1990-07-01

459

A low-background gamma-ray assay laboratory for activation analysis  

NASA Astrophysics Data System (ADS)

The sources of background in a gamma-ray detector were experimentally determined in underground and surface counting rooms, and an optimized shield was constructed at NIST. The optimum thickness of lead was 10-15 cm, with a greater thickness giving an increased background due to the buildup of tertiary cosmic-ray particles. Neither cadmium, tin, copper nor plastic (hydrocarbon or fluorocarbon) was desirable as a shield liner, since all these increased the background continuum or introduced characteristic peaks into the background spectrum. Two broad peaks in the background result from inelastic scattering of cosmic-ray neutrons (0.02 cm-2 s-1) in germanium. These neutrons also excite the lower nuclear levels of lead and structural iron to produce additional gamma-ray peaks in the spectrum. The influence of the 20 MW NIST reactor, located 60 m from the detector, was undetectable. Comparisons among detectors and locations clearly separate cosmic from environmental components of the background.

Lindstrom, Richard M.; Lindstrom, David J.; Slaback, Lester A.; Langland, John K.

1990-12-01

460

Transparent superhydrophobic and highly oleophobic coatings.  

PubMed

We report a facile process for fabrication of transparent superhydrophobic and highly oleophobic surfaces through assembly of silica nanoparticles and sacrificial polystyrene nanoparticles. The silica and polystyrene nanoparticles are first deposited by a layer-by-layer assembly technique. The polystyrene nanoparticles are then removed by calcination, which leaves a porous network of silica nanoparticles. The cavities created by the sacrificial polystyrene particles form overhang structures on the surfaces. Modified with a fluorocarbon molecule, such surfaces are superhydrophobic and transparent. They also repel liquids with low surface tensions, such as hexadecane, due to the overhang structures that prevent liquids from getting into the air pockets even though the intrinsic contact angles of these liquids are less than 90 degrees. PMID:21043414

Cao, Liangliang; Gao, Di

2010-01-01

461

The importance of the Montreal Protocol in protecting climate.  

PubMed

The 1987 Montreal Protocol on Substances that Deplete the Ozone Layer is a landmark agreement that has successfully reduced the global production, consumption, and emissions of ozone-depleting substances (ODSs). ODSs are also greenhouse gases that contribute to the radiative forcing of climate change. Using historical ODSs emissions and scenarios of potential emissions, we show that the ODS contribution to radiative forcing most likely would have been much larger if the ODS link to stratospheric ozone depletion had not been recognized in 1974 and followed by a series of regulations. The climate protection already achieved by the Montreal Protocol alone is far larger than the reduction target of the first commitment period of the Kyoto Protocol. Additional climate benefits that are significant compared with the Kyoto Protocol reduction target could be achieved by actions under the Montreal Protocol, by managing the emissions of substitute fluorocarbon gases and/or implementing alternative gases with lower global warming potentials. PMID:17360370

Velders, Guus J M; Andersen, Stephen O; Daniel, John S; Fahey, David W; McFarland, Mack

2007-03-08

462

Investigation of structure-surface properties relationship of semi-fluorinated polymerizable cationic surfactants.  

PubMed

Novel hybrid hydrocarbon/fluorocarbon ammonium type surfactant monomers (surfmers) of the general formula RF (CH2)l N(CH3)2(CH2)mOCOCH=CH2 with (RF=C4F9, C6F13, C8F17, l=4, 6, 11, and m=2-11) were synthesized and characterized. They exhibit very low surface tension as well as low critical micellar concentrations down to 1.39×10(-5)mol/L. Special attention was focused on theeffect of the polymerizable moiety, the length of the hydrocarbon spacers, and the fluorinated chains on surface activities of the reactive surfactants as compared to hydrocarbon surfmer analogs. Results indicate that the acrylic function has a pronounced effect on increasing the hydrophobic micelle character. This was confirmed by surface tensions and average surfaces occupied by these molecules at the water-gas interface. The micellar sizes were investigated by dynamic light scattering. PMID:23932087

Benbayer, Chahinez; Saidi-Besbes, Salima; Taffin de Givenchy, Elisabeth; Amigoni, Sonia; Guittard, Frédéric; Derdour, Aicha

2013-07-24

463

Gas chromatographic analysis of toxic edemagenic inhalation compounds  

SciTech Connect

Different megabore column and packed column phases were evaluated for their suitability in the gas chromatographic analysis of three toxic polyhalogenated compounds (phosgene, TFD, and PFIB). Adsorbent type stationary phases provide better retention and separation for the volatile fluorocarbons than do polar and nonpolar liquid phases. The reactivity of phosgene precludes the use of many phases having hydroxy, amino, or cyano functional groups. Silica gel is still the column of choice for phosgene. The use of gas sampling bags and gas-tight syringes can provide reliable quantitation of these compounds in air samples. TFD and PFIB exhibit different electron capture mechanisms and detector temperature dependency. The mechanisms are supported by the results of negative ion mass spectrometry.

Shih, M.L.; Smith, J.R.; McMonagle, J.D. (Army Medical Research Inst. of Chemical Defense, Aberdeen Proving Ground, MD (United States))

1990-01-01

464

National Institute for Occupational Safety and Health Cooperative Agreement, Award No. 1, U01 oh 01249-01. Final report  

SciTech Connect

A walk-through survey and a followup on/site environmental and medical evaluation of potentially exposed workers were carried out at Hill Air Force Base, Ogden, Utah. Followup on/site environmental and medical evaluations of potentially exposed workers were conducted at Koldaire, Inc., Salt Lake City, Utah. Past medical records at Hill Air Force Base and historical worker-exposure information were deemed adequate to reconstruct probable exposures to hazardous materials during the performance of various work assignments at the base and to permit a morbidity study to be conducted. Possible exposures in this area of work include fluorocarbons, phosgene, hydrogenchloride, hydrogen-fluoride, welding fumes and cadmium. It was recommended that respirators be worn by refrigeration repairmen, that medical surveillance be performed yearly, and that eye protection be worn during welding and soldering operations.

Rom, W.N.

1982-12-31

465

Oil fill procesure for seismic marine streamer  

SciTech Connect

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.

Buckles, J.J.

1990-08-21

466

PFC Decontamination of a Metal Surface and the Recycling of a Spent PFC Solution  

SciTech Connect

PFC (per-fluorocarbon) ultrasonic decontamination behavior of loosely contaminated metal specimens such as a plate, pipe, welding and a crevice specimen in a mixed solution of PFC and an anionic surfactant was investigated. Perfluoroheptane (C{sub 7}F{sub 16}) was used as a PFC ultrasonic media. The contaminants were completely removed for almost all of the tested specimens except for the longest pipe length specimen. For the 6-cm long specimen, 98.5 % of the contaminants were removed. For the recycling of the PFC solution, a distillation test for the spent PFC solution was also performed. The results show that 97.5 % of the PFC was recycled without a loss of the decontamination efficiency. (authors)

Jung, C.H.; Won, H.J.; Oh, W.Z.; Moon, J.K.; Park, J.H. [Korea Atomic Energy Research Institute, P.O.BOX 105, Yuseong-gu, Daejeon, 305-600 (Korea, Republic of)

2006-07-01

467

Ionic cleaning after wave solder and before conformal coat  

NASA Astrophysics Data System (ADS)

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.

Nguygen, Tochau N.; Sutherland, Thomas H.

468

Thermodynamic and transport properties of some alternative ozone-safe refrigerants for industrial refrigeration equipment: Study in Belarus and Ukraine  

SciTech Connect

The study of several hydrofluorocarbons (HFC) and fluorocarbons (FC) and their binary mixtures that have no ozone-depleting ability is being carried out in the framework of Belarus National program. The fluids include HFCs R134a, R152a, R125, and R32, and FC R218. The following properties are being investigated: (1) phase equilibrium parameters including the boiling and condensing curve and critical point, thermophysical properties at these parameters, and heat of evaporation; (2) isobaric and isochoric heat capacity, ethalpy, and entropy in the gas and liquid state; (3) speed of sound, thermal conductivity, viscosity, and density in the gas and liquid state; (4) dielectric properties and surface tension; (5) behavior of combined construction materials inside the refrigerant medium; and (6) solubility in compressor oils and other technological characteristics. The series of results obtained by authors during the period 1990-1993 is presented.

Grebenkov, A.J.; Klepatsky, P.M.; Beljajeva, O.V. [Inst. of Power Engineering Problems, Minsk (Belgium)] [and others

1996-05-01

469

Electrical Conductance of Hydrophobic Membranes or What Happens Below the Surface  

PubMed Central

Nanoporous alumina membranes rendered hydrophobic by surface modification via covalent attachment of hydrocarbon or fluorocarbon chains conduct electricity via surface even when the pores are not filled with electrolyte. The resistance is many orders of magnitude higher than for electrolyte filled membranes and does not depend on the electrolyte concentration or pH but it does depend on the type of hydrophobic monolayer and its density. The corresponding surface resistance varies from greater than 1018 ?/? to less than 3×109 ?/?. When the hydrophobic monolayer contains a small proportion of photoactive spiropyran that is insufficient to switch the surface to hydrophilic after spiropyran photoisomerization to the merocyanine form, the membrane resistance also becomes light-dependent with a reversible increase of surface resistance by as much as 15%. Surface conduction is ascribed to hydration and ionization of the alumina surface hydroxyls and the ionizable groups of the hydrophobic surface modifiers.

Vlassiouk, Ivan; Rios, Fabian; Vail, Sean A.; Gust, Devens; Smirnov, Sergei

2008-01-01

470

The Effect of Oil Contamination on Evaporator Heat Transfer Characteristics of CO2 Refrigeration Cycle  

NASA Astrophysics Data System (ADS)

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.

Katsuta, Masafumi; Kinpara, Hiromitsu; Yagi, Shunta; Mukaiyama, Hiroshi

471

Surface characteristics of etched parylene-C films for low-damaged patterning process using inductively-coupled O2/CHF3 gas plasma  

NASA Astrophysics Data System (ADS)

We investigated the effectiveness of CHF3 admixture in O2 plasma for a low damage patterning process. We used inductively-coupled plasma (ICP) etching of parylene-C thin films with O2/CHF3 gas mixtures. Plasma diagnostics were performed by using a double Langmuir probe. Also in order to examine the relationship between the plasma and surface energy, we attempted to conduct a simplified model-based analysis of the CHF3/O2 plasma.The surface energy decreased as the admixture fraction increased with fluorocarbon containing gas. The decreased surface energy is related to the functional groups of CFx polymer at binding energy of around 290 eV and low ion physical damage. We observed that a small addition of CHF3 to O2 plasma produced a high etch rate, low surface energy, and low roughness compared to pure oxygen plasma.

Ham, Yong-Hyun; Shutov, Dmitriy Alexandrovich; Kwon, Kwang-Ho

2013-05-01

472

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

SciTech Connect

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.

Zhou Baosuo; Joseph, Eric A.; Sant, Sanket P.; Liu Yonghua; Radhakrishnan, Arun; Overzet, Lawrence J.; Goeckner, Matthew J. [Department of Electrical Engineering, University of Texas at Dallas, Richardson, Texas 75083-0688 (United States)

2005-11-15

473

Isolation of native Mauthner cell axoplasm and an analysis of organelle movement in non-aqueous and aqueous media.  

PubMed

A method for isolating Mauthner cell (M-cell) axoplasm from goldfish is described. The axon may be isolated in a fluorocarbon oil (e.g., Fluorinert), or in an aqueous bathing medium (ABM). An analysis of motile organelles in axoplasm isolated in Fluorinert or in ABM indicated that the range of particle velocities extended over an order of magnitude, and that there was a significant selective slowing of retrograde particle movement in axons isolated in ABM. No apparent correlation between particle size and velocity was noted. In addition to confirming that calcium was not required for particle transport, it was observed that adenylylimidodiphosphate produced an irreversible blockade of organelle movements, suggesting that force generating mechanisms involved in translocation are probably similar to those proposed for invertebrate axons. PMID:2432995

Koenig, E

1986-11-29

474

The importance of the Montreal Protocol in protecting climate  

PubMed Central

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.

Velders, Guus J. M.; Andersen, Stephen O.; Daniel, John S.; Fahey, David W.; McFarland, Mack

2007-01-01

475

Nano-coatings on carbon structures for interfacial modification  

NASA Astrophysics Data System (ADS)

Surface modification of materials is a rapidly growing field as structures become smaller, more integrated and complex. It opens up the possibility of combining the optimum bulk properties of a material with optimized surface properties such as enhanced bonding, corrosion resistance, reactivity, stress transfer, and thermal, optical or electrical behavior. Therefore, surface functionalization or modification can be an enabling step in a wide variety of modern applications. In this dissertation several surface modification approaches on carbon foam and carbon nano-fibers will be discussed. These are recently developed sp2 graphitic carbon based structures that have significant potential in aerospace, automotive and thermal applications. Influence of surface modification on composite formation and properties have also been investigated. Two types of property changes have been investigated: one for enhancing the surface reactivity and another for surface inertness. Characterization techniques such as X-ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM), Contact Angle Measurement, Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) and mechanical testing are used in this study to find out the influence of these coatings on surface composition, chemistry and morphology. Mechanical testing has been performed on composites and stand