WorldWideScience

Sample records for plasma polymerization process

  1. Antireflection coatings on plastics deposited by plasma polymerization process

    Indian Academy of Sciences (India)

    K M K Srivatsa; M Bera; A Basu; T K Bhattacharya

    2008-08-01

    Antireflection coatings (ARCs) are deposited on the surfaces of optical elements like spectacle lenses to increase light transmission and improve their performance. In the ophthalmic industry, plastic lenses are rapidly displacing glass lenses due to several advantageous features. However, the deposition of ARCs on plastic lenses is a challenging task, because the plastic surface needs treatment for adhesion improvement and surface hardening before depositing the ARC. This surface treatment is usually done in a multi-stage process—exposure to energetic radiations, followed by deposition of a carbonyl hard coating by spin or dip coating processes, UV curing, etc. However, this treatment can also be done by plasma processes. Moreover, the plasma polymerization process allows deposition of optical films at room temperature, essential for plastics. The energetic ions in plasma processes provide similar effects as in ion assisted physical deposition processes to produce hard coatings, without requiring sophisticated ion sources. The plasma polymerization process is more economical than ion-assisted physical vapour deposition processes as regards equipment and source materials and is more cost-effective, enabling the surface treatment and deposition of the ARC in the same deposition system in a single run by varying the system parameters at each step. Since published results of the plasma polymerization processes developed abroad are rather sketchy and the techniques are mostly veiled in commercial secrecy, innovative and indigenous plasma-based techniques have been developed in this work for depositing the complete ARCs on plastic substrates.

  2. Plasma polymerization by Softplasma

    DEFF Research Database (Denmark)

    Jiang, J.; Wu, Zhenning; Benter, Maike

    2008-01-01

    In the late 19th century, the first depositions - known today as plasma polymers, were reported. In the last century, more and more research has been put into plasma polymers. Many different deposition systems have been developed. [1, 2] Shi F. F. broadly classified them into internal electrode......, external electrode, and electrodeless microwave or high frequency reactors. [3] Softplasma™ is an internal electrode plasma setup powered by low frequenc~ gower supply. It was developed in late 90s for surface treatment of silicone rubber. [ ]- 5] It is a low pressure, low electron density, 3D homogenous...... plasma. In this study, we are presenting the surface modification"pf polymers by plasma polymerization using Softplasma™. Softplasma™ can be used for two major types of polymerization: polymerization of vinyl monomers, where plasma acts as initiator; chemical vapour deposition, where plasma acts...

  3. Organic plasma process for simple and substrate-independent surface modification of polymeric BioMEMS devices.

    Science.gov (United States)

    Hiratsuka, Atsunori; Muguruma, Hitoshi; Lee, Kyong-Hoon; Karube, Isao

    2004-07-15

    A polymeric bio micro electromechanical systems (BioMEMS) device was fabricated using organic plasma polymerization, by which the surface of a polymeric substrate could easily be modified through vapor-phase deposition of organic thin films. This technique, capable of polymeric deposition of any kind of monomer, can serve the purpose of anti-fouling coating, wettability control, or layer-to-layer interface creation, on the surface of any given chemically-inert polymeric substrate without involving cumbersome surface organic reactions. A prototype device was fabricated to have an array of electrochemical glucose biosensors with the three electrode configuration, each of which has a microfluidic channel (500 microm x 800 microm) for capillary-action-driven sample delivery and the concerned enzymatic reaction. Stressing the advantages of the plasma polymerization process using a polymeric substrate together with some additional features accomplished in our device fabrication, new possibilities in the field of polymeric BioMEMS are discussed.

  4. Controlling the Plasma-Polymerization Process of N-Vinyl-2-pyrrolidone

    DEFF Research Database (Denmark)

    Norrman, Kion; Winther-Jensen, Bjørn

    2005-01-01

    N-vinyl-2-pyrrolidone was plasma-polymerized on glass substrates using a pulsed AC plasma. Pulsed AC plasma produces a chemical surface structure different from that produced by conventional RF plasma; this is ascribed to the different power regimes used. A high degree of control over the structure...... of the chemical surface was obtained using pulsed AC plasma, as shown by ToF-SIMS. It is demonstrated how the experimental conditions to some extent control the chemical structure of the plasma-polymerized film, e.g., film thickness, density of post-plasma-polymerized oligomeric chains, and the density of intact...

  5. Enhancement of proton conductivity of sulfonated polystyrene membrane prepared by plasma polymerization process

    Indian Academy of Sciences (India)

    Bhabesh Kumar Nath; Aziz Khan; Joyanti Chutia; Arup Ratan Pal; Heremba Bailung; Neelotpal Sen Sarma; Devasish Chowdhury; Nirab Chandra Adhikary

    2014-12-01

    This work reports the achievement of higher proton conductivity of polystyrene based proton exchange membrane synthesized in a continuous RF plasma polymerization process using two precursors, styrene (C8H8) and trifluoromethane sulfonic acid (CF3SO3H). The chemical composition of the developed membranes is investigated using Fourier transform infrared spectroscopy and energy dispersive spectroscopy. Scanning electron microscopy has been used for the study of surface morphology and thickness measurement of the membrane. The membranes deposited in the power range from 0.114 to 0.318 Wcm-2 exhibit a lot of variation in the properties like proton transport, water uptake, sulfonation rate, ion exchange capacity and thermal behaviour. The proton conductivity of the membranes is achieved up to 0.6 Scm-1, measured with the help of potentiostat/galvanostat. The thermogravimetric study of the plasma polymerized membrane shows the thermal stability up to 140 °C temperature.

  6. Atmospheric pressure plasma processing of polymeric materials utilizing close proximity indirect exposure

    Energy Technology Data Exchange (ETDEWEB)

    Paulauskas, Felix L.; Bonds, Truman

    2016-09-20

    A plasma treatment method that includes providing treatment chamber including an intermediate heating volume and an interior treatment volume. The interior treatment volume contains an electrode assembly for generating a plasma and the intermediate heating volume heats the interior treatment volume. A work piece is traversed through the treatment chamber. A process gas is introduced to the interior treatment volume of the treatment chamber. A plasma is formed with the electrode assembly from the process gas, wherein a reactive species of the plasma is accelerated towards the fiber tow by flow vortices produced in the interior treatment volume by the electrode assembly.

  7. Challenges in the characterization of plasma-processed three-dimensional polymeric scaffolds for biomedical applications.

    Science.gov (United States)

    Fisher, Ellen R

    2013-10-09

    Low-temperature plasmas offer a versatile method for delivering tailored functionality to a range of materials. Despite the vast array of choices offered by plasma processing techniques, there remain a significant number of hurdles that must be overcome to allow this methodology to realize its full potential in the area of biocompatible materials. Challenges include issues associated with analytical characterization, material structure, plasma processing, and uniform composition following treatment. Specific examples and solutions are presented utilizing results from analyses of three-dimensional (3D) poly(ε-caprolactone) scaffolds treated with different plasma surface modification strategies that illustrate these challenges well. Notably, many of these strategies result in 3D scaffolds that are extremely hydrophilic and that enhance human Saos-2 osteoblast cell growth and proliferation, which are promising results for applications including tissue engineering and advanced biomedical devices.

  8. Plasma polymerization by Softplasma

    DEFF Research Database (Denmark)

    Jiang, J.; Wu, Zhenning; Benter, Maike

    2008-01-01

    as reactive splvent (as shown in Figure 1). 1] H. Biederman, in Plasma Polymer Films. (ed.) H. Biederman. Imperial College Press, Singapore, 13-24 ~OO~· '. , [2] R. d'Agostino et.a!. in Plasma Depd~itiqn, 'Treatment, and Etching ofPolymers. (ed.) R. d'Agostino, Academic Press, U.S. (1990). [3] F. F. Shi......In the late 19th century, the first depositions - known today as plasma polymers, were reported. In the last century, more and more research has been put into plasma polymers. Many different deposition systems have been developed. [1, 2] Shi F. F. broadly classified them into internal electrode......, external electrode, and electrodeless microwave or high frequency reactors. [3] Softplasma™ is an internal electrode plasma setup powered by low frequenc~ gower supply. It was developed in late 90s for surface treatment of silicone rubber. [ ]- 5] It is a low pressure, low electron density, 3D homogenous...

  9. Living olefin polymerization processes

    Science.gov (United States)

    Schrock, Richard R.; Baumann, Robert

    1999-01-01

    Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.

  10. Up-scaling the production of modified a-C:H coatings in the framework of plasma polymerization processes

    Science.gov (United States)

    Corbella, C.; Bialuch, I.; Kleinschmidt, M.; Bewilogua, K.

    2009-10-01

    Hydrogenated amorphous carbon (a-C:H) films with silicon and oxygen additions, which exhibit mechanical, tribological and wetting properties adequate for protective coating performance, have been synthesized at room temperature in a small- (0.1 m 3) and a large-scale (1 m 3) coaters by low-pressure Plasma-Activated Chemical Vapour Deposition (PACVD). Hence, a-C:H:Si and a-C:H:Si:O coatings were produced in atmospheres of tetramethylsilane (TMS) and hexamethyldisiloxane (HMDSO), respectively, excited either by radiofrequency (RF - small scale) or by pulsed-DC power (large scale). Argon was employed as a carrier gas to stabilize the glow discharge. Several series of 2-5 μm thick coatings have been prepared at different mass deposition rates, Rm, by varying total gas flow, F, and input power, W. Arrhenius-type plots of Rm/ F vs. ( W/ F) -1 show linear behaviours for both plasma reactors, as expected for plasma polymerization processes at moderated energies. The calculation of apparent activation energy, Ea, in each series permitted us to define the regimes of energy-deficient and monomer-deficient PACVD processes as a function of the key parameter W/ F. Moreover, surface properties of the modified a-C:H coatings, such as contact angle, abrasive wear rate and hardness, appear also correlated to this parameter. This work shows an efficient methodology to scale up PACVD processes from small, lab-scale plasma machines to industrial plants by the unique evaluation of macroscopic parameters of deposition.

  11. Polymerization monitoring in plasma etching systems

    Science.gov (United States)

    Kim, Jinsoo

    1999-11-01

    In plasma etching processes, the polymers used to enhance etch anisotropy and selectivity also deposit on various parts of the reaction chamber. This polymerization on reactor surface not only strongly affects the concentration of reactants in the plasma discharge, eventually changing the etching characteristics, but also can produce particulates which lower yield. This thesis explores the development of a direct in-situ polymerization monitoring sensor to minimize the drifts in plasma etching processes. In addition, polymerization dependencies on basic processing parameters and polymerization effects on etching characteristics have been explored for the first time using a direct in-situ sensor. The polymer buildup process is a strong function of parameters such as power, base pressure, and flow rate, and is also dependent on the reactor materials used, temperature, and the hydrogen/oxygen concentrations present. Experiments performed in an Applied Materials 8300 plasma etcher show a significant increase in polymerization with increased pressure and flow rates and a decrease as a function of power. These experiments provide insight into how the chamber state changes under the different processing recipes used for etching specific material layers and also suggest how the chamber seasoning process can best be carried out. The reactor surface, which serves as both a source and a sink for reactive gas species, not only strongly affects the concentration of reactants in the plasma discharge, eventually changing the etching characteristics, but also can produce particulates which lower yield. The etch rate and selectivity variations for specific silicon dioxide and silicon nitride etching recipes have been explored as a function of the polymer thickness on the reactor walls. The etch rates of nitride and polysilicon decrease dramatically with polymer thickness up to a thickness of 60nm, while the oxide etch rate remains virtually constant due to the polymerization

  12. Reverse-osmosis membranes by plasma polymerization

    Science.gov (United States)

    Hollahan, J. R.; Wydeven, T.

    1972-01-01

    Thin allyl amine polymer films were developed using plasma polymerization. Resulting dry composite membranes effectively reject sodium chloride during reverse osmosis. Films are 98% sodium chloride rejective, and 46% urea rejective.

  13. Plasma polymerized allylamine coated quartz particles for humic acid removal.

    Science.gov (United States)

    Jarvis, Karyn L; Majewski, Peter

    2012-08-15

    Allylamine plasma polymerization has been used to modify the surface of quartz particles for humic acid removal via an inductively coupled rotating barrel plasma reactor. Plasma polymerized allylamine (ppAA) films were deposited at a power of 25 W, allylamine flow rate of 4.4 sccm and polymerization times of 5-60 min. The influence of polymerization time on surface chemistry was investigated via X-ray photoelectron spectroscopy (XPS), time of flight secondary ion mass spectrometry (ToF-SIMS) and electrokinetic analysis. Acid orange 7 adsorption/desorption quantified the number of surface amine groups. Humic acid removal via ppAA quartz particles was examined by varying pH, removal time, humic acid concentration, and particle mass. Increasing the polymerization time increased the concentration of amine groups on the ppAA quartz surface, thus also increasing the isoelectric point. ToF-SIMS demonstrated uniform distribution of amine groups across the particle surface. Greatest humic acid removal was observed at pH 5 due to electrostatic attraction. At higher pH values, for longer polymerization times, humic acid removal was also observed due to hydrogen bonding. Increasing the initial humic acid concentration increased the mass of humic acid removed, with longer polymerization times exhibiting the greatest increases. Plasma polymerization using a rotating plasma reactor has shown to be a successful method for modifying quartz particles for the removal of humic acid. Further development of the plasma polymerization process and investigation of additional contaminants will aid in the development of a low cost water treatment system.

  14. AQUEOUS STABLE FREE RADICAL POLYMERIZATION PROCESSES

    Institute of Scientific and Technical Information of China (English)

    Andrea R. Szkurhan; Michael K. Georges

    2004-01-01

    An overview of aqueous polymerizations, which include emulsion, miniemulsion and suspension polymerizations,under stable free radical polymerization (SFRP) conditions is presented. The success of miniemulsion and suspension SFRP polymerizations is contrasted with the difficulties associated with obtaining a stable emulsion polymerization. A recently developed unique microprecipitation technique is referenced as a means of making submicron sized particles that can be used to achieve a stable emulsion SFRP process.

  15. Modeling the chemistry of plasma polymerization using mass spectrometry.

    Science.gov (United States)

    Ihrig, D F; Stockhaus, J; Scheide, F; Winkelhake, Oliver; Streuber, Oliver

    2003-04-01

    The goal of the project is a solvent free painting shop. The environmental technologies laboratory is developing processes of plasma etching and polymerization. Polymerized thin films are first-order corrosion protection and primer for painting. Using pure acetylene we get very nice thin films which were not bonded very well. By using air as bulk gas it is possible to polymerize, in an acetylene plasma, well bonded thin films which are stable first-order corrosion protections and good primers. UV/Vis spectroscopy shows nitrogen oxide radicals in the emission spectra of pure nitrogen and air. But nitrogen oxide is fully suppressed in the presence of acetylene. IR spectroscopy shows only C=O, CH(2) and CH(3) groups but no nitrogen species. With the aid of UV/Vis spectra and the chemistry of ozone formation it is possible to define reactive traps and steps, molecule depletion and processes of proton scavenging and proton loss. Using a numerical model it is possible to evaluate these processes and to calculate theoretical mass spectra. Adjustment of theoretical mass spectra to real measurements leads to specific channels of polymerization which are driven by radicals especially the acetyl radical. The estimated theoretical mass spectra show the specific channels of these chemical processes. It is possible to quantify these channels. This quantification represents the mass flow through this chemical system. With respect to these chemical processes it is possible to have an idea of pollutant production processes.

  16. Nanometer scale vacuum lithography using plasma polymerization and plasma etching

    CERN Document Server

    Kim, S O

    1998-01-01

    Thin films of plasma polymerization were fabricated through plasma polymerization of interelectrode capacitively coupled gas flow system. After delineating the pattern with an accelerating voltage of 30kV, ranging the dose of 1 approx 500 mu C/cm sup 2 , the pattern was developed with a dry type and formed by plasma etching. By analyzing the molecule structure using FT-IR ( Fourier Transform-Infrared Spectrometry), it was confirmed that the thin films of PPMST (Plasma Polymerized Methylmethacrylate+Styrene+Tetramethyltin) contained the functional radicals of the MST (Methylmethacrylate sub S tyrene+Tetramethyltin) monomer. The Thin films of PPMST had a highly cross-linked structure resulting in a higher molecule weight than the conventional resist. The deposition rate of the PPMST thin films was 230 approx 600 A/min as a function of 50 approx 200 W power and 200 approx 60 A/min as a function 0.1 approx 0.7 Torr pressure. The etching rate of the thin films of PPMST was 875 approx 3520 A/min as a function of 50...

  17. PLASMA POLYMERIZATION OF ACETYLENE/CO2/H2

    Institute of Scientific and Technical Information of China (English)

    ZHENG Ji; FANG Yuee; SHI Tianyi; SHOHEI INOUE

    1989-01-01

    A study has been made on the plasma polymerization of acetylene/CO2/H2 in a capacitively coupled RF plasma. The monomer mixture yielded a crosslinked film with light brown color. A kinetic study is reported for the plasma polymerization of acetylene/CO2/H2. The effects of discharge power level and reactor geometry on the rate of polymer formation are reported. The structure of the plasma polymer is investigated by IR study.

  18. Organic nanocones fabricated by atmospheric plasma polymerization for immobilizing bioprobes

    Energy Technology Data Exchange (ETDEWEB)

    Chen Guangliang; Chen Wenxing [Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Chen Shihua; Zhou Mingyan [Department of Civil and Environmental Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180 (United States); Yang Size [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China)], E-mail: glchen@zstu.edu.cn

    2008-02-20

    Inspired by the formation process of natural thundershowers, we fabricated an organic nanocone matrix-like bamboo-shoot by using atmospheric plasma polymerization in the absence of any catalyst or template. The discharging characteristics affected the nanocone shape and distribution in an obvious way. The nanocones prepared by helium (He) plasma were about 120 nm in diameter and 80 nm high. The nanostructured surface acted as an adhesion layer immobilizing DNA probes for DNA hybridization assay. The density of NH{sub 2}-DNA probes prepared by He, argon (Ar) and nitrogen (N{sub 2}) plasma was confirmed by the dyed oligonucleotide and was found to be 3.2, 1.0 and 0.6 pM cm{sup -2}, respectively. Each nanocone prepared by helium plasma contains nearly 4 x 10{sup 2} amine groups.

  19. Polymerization of acrylic acid using atmospheric pressure DBD plasma jet

    Science.gov (United States)

    Bashir, M.; Bashir, S.

    2016-08-01

    In this paper polymerization of acrylic acid was performed using non thermal atmospheric pressure plasma jet technology. The goal of this study is to deposit organic functional coatings for biomedical applications using a low cost and rapid growth rate plasma jet technique. The monomer solution of acrylic acid was vaporized and then fed into the argon plasma for coating. The discharge was powered using a laboratory made power supply operating with sinusoidal voltage signals at a frequency of 10 kHz. The optical emission spectra were collected in order to get insight into the plasma chemistry during deposition process. The coatings were characterized using Fourier transform infrared spectroscopy, atomic force microscopy and growth rates analysis. A high retention of carboxylic functional groups of the monomer was observed at the surface deposited using this low power technique.

  20. Composite plasma polymerized sulfonated polystyrene membrane for PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Nath, Bhabesh Kumar; Khan, Aziz; Chutia, Joyanti, E-mail: jchutiaiasst@gmail.com

    2015-10-15

    Highlights: • Methyl methane sulfonate (MMS) is used as the sulfonating agent. • The proton conductivity of the membrane is found to be 0.141 S cm{sup −1}. • Power density of fuel cell with styrene/MMS membrane is 0.5 W cm{sup −2}. • The membrane exhibits thermal stability up to 140 °C. - Abstract: This work presents the introduction of an organic compound methyl methane sulfonate (MMS) for the first time in fabrication of polystyrene based proton exchange membrane (PEM) by plasma polymerization process. The membrane is fabricated by co-polymerizing styrene and MMS in capacitively coupled continuous RF plasma. The chemical composition of the plasma polymerized polymer membrane is investigated using Fourier Transform Infrared Spectroscopy which reveals the formation of composite structure of styrene and MMS. The surface morphology studied using AFM and SEM depicts the effect of higher partial pressure of MMS on surface topography of the membrane. The proton transport property of the membrane studied using electrochemical impedance spectroscopy shows the achievement of maximum proton conductivity of 0.141 S cm{sup −1} which is comparable to Nafion 117 membrane. Fuel cell performance test of the synthesized membrane shows a maximum power density of 500 mW cm{sup −2} and current density of 0.62 A cm{sup −2} at 0.6 V.

  1. Selective Plasma Etching of Polymeric Substrates for Advanced Applications.

    Science.gov (United States)

    Puliyalil, Harinarayanan; Cvelbar, Uroš

    2016-06-07

    In today's nanoworld, there is a strong need to manipulate and process materials on an atom-by-atom scale with new tools such as reactive plasma, which in some states enables high selectivity of interaction between plasma species and materials. These interactions first involve preferential interactions with precise bonds in materials and later cause etching. This typically occurs based on material stability, which leads to preferential etching of one material over other. This process is especially interesting for polymeric substrates with increasing complexity and a "zoo" of bonds, which are used in numerous applications. In this comprehensive summary, we encompass the complete selective etching of polymers and polymer matrix micro-/nanocomposites with plasma and unravel the mechanisms behind the scenes, which ultimately leads to the enhancement of surface properties and device performance.

  2. Selective Plasma Etching of Polymeric Substrates for Advanced Applications

    Directory of Open Access Journals (Sweden)

    Harinarayanan Puliyalil

    2016-06-01

    Full Text Available In today’s nanoworld, there is a strong need to manipulate and process materials on an atom-by-atom scale with new tools such as reactive plasma, which in some states enables high selectivity of interaction between plasma species and materials. These interactions first involve preferential interactions with precise bonds in materials and later cause etching. This typically occurs based on material stability, which leads to preferential etching of one material over other. This process is especially interesting for polymeric substrates with increasing complexity and a “zoo” of bonds, which are used in numerous applications. In this comprehensive summary, we encompass the complete selective etching of polymers and polymer matrix micro-/nanocomposites with plasma and unravel the mechanisms behind the scenes, which ultimately leads to the enhancement of surface properties and device performance.

  3. The study of UHMWPEF surface modification with plasma- induced polymerization

    Science.gov (United States)

    Zhang, Yu-Fang; Jia, Qing-Xiu; Wang, Xin; Zhang, Pei-Ran

    2015-07-01

    In order to improve the surface activity levels of the ultrahigh molecular weight polyethylene fiber (UHMWPEF), as well as enhancing the interface strength of the UHMWPEF based composite materials, the method of plasma-induced polymerization was applied to modify the UHMWPEF surface. In this study, the plasma's power, time, pressure and the grafting monomer concentration were introduced. Also, through a well-conducted comparison and analysis of the grafting rate, fabric surface functional groups and the microcosmic morphology, the most suitable plasma modification process was discovered and determined. The mechanics performance of hybrid composites with the modified UHMWPEF and unidirectional carbon fiber cloth (CF) was tested to reveal that, compared with the unmodified composites, the tensile strength and the laminar shear strength could be improved.

  4. Novel polymer coatings based on plasma polymerized 2-methoxyethyl acrylate

    DEFF Research Database (Denmark)

    Wu, Zhenning; Jiang, Juan; Benter, Maike

    2008-01-01

    plasma system[4]. The system named SoftPlasma™ is equipped with unique three-phase pulsed AC voltage. Low energy plasma polymerization has almost no thermal load for sensitive polymer materials[5]. Plasma polymerized coatings are highly cross-linked, pin-hole free and provide hydrophilic or hydrophobic...... properties[4-6]. We have exploited these possibilities and prepared plasma polymerized 2-methoxyethyl acrylate (PPMEA) coatings on various polymer substrates. The PPMEA coatings were optimized using various plasma polymerization conditions and characterized by X-ray photoelectron spectroscopy......, Fouriertransform infrared spectroscopy, Atomic force spectroscopy and Water contact-angle measurements. The microstructures ofPPMEA coatings with different thicknesses were also studied. For practical applications in mind, the coating stability was tested in different media (air, water, acetone, phosphate...

  5. Charge trapping in plasma-polymerized thin films

    Science.gov (United States)

    Klemberg-Sapieha, J. E.; Sapieha, S.; Wertheimer, M. R.; Yelon, A.

    1980-07-01

    The surface potential of freshly plasma-polymerized films of hexamethyldisiloxane was measured for film thicknesses ranging from about 0.1 to 1 micron. The films are found to be in an electret state under certain fabrication conditions. Experimental evidence is given which indicates that charge trapped during plasma polymerization is uniformly distributed across the sample thickness. It has been found that other electret properties such as the polarity of trapped charge, and the charge retention characteristics can also be controlled by an appropriate choice of polymerization conditions.

  6. PLASMA POLYMERIZED ORGANOSILANES AS A PROTECTIVE COATING ON METAL

    Institute of Scientific and Technical Information of China (English)

    SUN Qiushi; HOU Xiaohua

    1997-01-01

    Polymer-metal oxane bonds (M-O-Si) can be created in the form of tight networks by silane plasma polymerization directly on the metal (e.g. copper) substrates. In this paper the structure and properties of the plasma-deposited organosilane polymers, the corrosion performance of such coating system on copper substrates were investigated.

  7. Surface characterization and platelet adhesion studies on fluorocarbons prepared by plasma-induced graft polymerization.

    Science.gov (United States)

    Lin, J C; Tiong, S L; Chen, C Y

    2000-01-01

    It is believed that the interactions between the biological environment and biomaterial surface are the key factors influencing its biocompatibility. Therefore, plasma processing, which can vary the surface properties without altering the bulk properties, has been considered as one of the important techniques for improving a materials' biocompatibility. In this investigation, plasma-induced grafting polymerization of vinylidene fluoride (VDF) and chlorotrifluoroethylene (CTFE), instead of direct plasma polymerization, was attempted with an aim to improve the substrate blood compatibility. Contact angle measurement indicated both fluorocarbon-grafted Pdyethylenes (PEs) are hydrophobic. Due to the additional fluorine and chlorine atoms on the CTFE chain, the PCTFE-grafted PE exhibited a higher hydrophobicity than the PVDF-grafted one. ESCA analysis has revealed that these two plasma-induced fluorocarbon deposits contain almost no CFx (x > 2) binding on the surface layer, indicating the grafting polymerization mainly follows the free radical mechanism instead of the molecule-highly-fragmented reaction steps commonly seen in the direct plasma polymerization treatment. In addition, ATR-FTIR has shown the surface chemical configuration of these PVDF- and PCTFE-grafted PEs to be very similar to those of the bulk samples of PVDF and PCTFE. The surface roughness decreased after oxygen plasma treatment and was further reduced by VDF and CTFE grafting polymerization. In vitro platelet adhesion testing indicated these two fluorocarbon grafted PEs are less platelet-activating than the nontreated PE control and oxygen plasma activated one.

  8. Durable Nanolayer Graft Polymerization of Functional Finishes Using Atmospheric Plasma

    Science.gov (United States)

    Mazloumpour, Maryam

    Various applications of atmospheric pressure plasma were investigated in conjunction with different chemistries on nonwoven materials including spunbond polyester (PET) and spunbod polypropylene for fuel separation and antimicrobial functionalities. Hydrophobic/Oleophobic properties were conferred on nonwoven polyester (PET) via plasma-induced graft polymerization of different hydrophobic non-C8 perfluorocarbon chemistry including perfluorohexylethylmethacrylate, perfluorohexylethylacrylate, allylpentafluorobenzene, pentafluorostyrene, or 1,3-divinyltetramethyldisiloxane in the vapor form using both in-situ and down-stream plasma configurations. Different nanolayers of the grafted polymer were furnished on nonwovens to generate surfaces with different level of wettabilities for medical applications and water/fuel separation. The effect of various hydrophobic chemistry, different plasma conditions, and plasma device parameters including plasma power and plasma exposure time were studied and the performance was characterized by measuring the contact angle and the wettability rating against liquids with broad range of surface tensions. Vapor deposition of 2-(perfluorohexyl)ethyl methacrylate and pentafluorostyrene on nonwoven PET followed by plasma-induced graft polymerization was investigated for possible use in water/fuel separation. Different nanolayer thicknesses (80-180nm) of the grafted polymer were achieved to generate surfaces with different wettabilities for water/fuel separation of different fuel compositions. The effect of different plasma conditions and device parameters including the flow rate of monomers, power of the device, and time of plasma exposure on the separation of different fuels was studied and characterized by measuring the surface energy of the treated substrates. The surface chemistry and morphology of the treated samples were characterized using XPS, SEM and TOF-SIMS techniques which confirmed the grafting of monomer onto the substrate

  9. Effect of Polymerization Condition on Particle Size Distribution in St/BA/MAA Emulsion Polymerization Process

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A series of St/BA/MAA emulsion polymerizations was carried out. By using PCS (photon correlation spectroscopy), the particle size distribution(PSD) of the whole St/BA/MAA emulsion polymerization process was gotten easily and quickly. The effect of polymerization condition on PSD in St/BA/MAA emulsion process was discussed.

  10. Plasma-induced graft-polymerization of polyethylene glycol acrylate on polypropylene substrates

    Science.gov (United States)

    Zanini, S.; Orlandi, M.; Colombo, C.; Grimoldi, E.; Riccardi, C.

    2009-08-01

    A detailed study of argon plasma-induced graft-polymerization of polyethylene glycol acrylate (PEGA) on polypropylene (PP) substrates (membranes and films) is presented. The process consists of four steps: (a) plasma pre-activation of the PP substrates; (b) immersion in a PEGA solution; (c) argon plasma-induced graft-polymerization; (d) washing and drying of the samples. Influence of the solution and plasma parameters on the process efficiency evaluated in terms of amount of grafted polymer, coverage uniformity and substrates wettability, are investigated. The plasma-induced graft-polymerization of PEGA is then followed by sample weighting, water droplet adsorption time and contact angle measurements, attenuated total reflection infrared spectroscopy (ATR-IR), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) analyses. The stability of the obtained thin films was evaluated in water and in phosphate buffer saline (PBS) at 37 °C. Results clearly indicates that plasma-induced graft-polymerization of PEGA is a practical methodology for anti-fouling surface modification of materials.

  11. Modification of surface properties of bell metal by radiofrequency plasma polymerization

    Science.gov (United States)

    Chutia, Joyanti; Choudhury, Arup Jyoti; Pal, Arup Ratan; Gogoi, Dolly

    2012-11-01

    Radiofrequency (RF) plasma polymerization is a convenient thin film deposition process as it facilitates the synthesis of polymer films with stable physico-chemical properties suitable for various applications in microelectronic, optical, and biomedical fields. The unique properties of these plasma polymerized films as compared to the conventional ones are strongly related to the proper adjustment of the external plasma discharge parameters and selection of suitable monomer. It is also important to study the fundamental chemistry of RF plasma polymerization process, so that one can successfully correlate the internal features of the discharge with the film properties and explore their possible technological applications. The possibility of using styrene-based plasma polymer (SPP) films on bell metal as protective coatings is explored in this work. Depositions of the films are carried out in RF Ar/styrene discharge at working pressure of 1.2 × 10-1 mbar and at the RF power range of 20 to 110 W. Optical emission spectroscopy (OES) is used to study the active species generated during plasma polymerization, while Fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS) are used to analyze the internal chemical structures of the films. The protective performances of the SPP films are attempted to correlate with the results obtained from OES, FT-IR, and XPS analyses.

  12. Plasma treatment for biomedical application on polymeric substrate

    OpenAIRE

    Ziano,

    2010-01-01

    This work arises from the possibility of changing the surface properties of materials with the use of plasma. It proved to be a very good method for treating surfaces, it is in fact able to modify surface properties of materials without altering their bulk properties. In particular, with the Plasma Enhanced Chemical Vapour Deposition (PECVD) is feasible sustaining the polymerization of a specific monomer depositing thin films containing interesting chemical groups. For these reasons, this ...

  13. Characterization of Plasma Polymerized Hexamethyldisiloxane Films Prepared by Arc Discharge

    NARCIS (Netherlands)

    Lazauskas, A.; Baltrusaitis, Jonas; Grigaliunas, V.; Jucius, D; Guobiene, A.; Prosycevas, I.; Narmontas, P.

    2014-01-01

    Herein, we present a simple method for fabricating plasma polymerized hexamethyldisiloxane films (pp-HMDSO) possessing superhydrophobic characteristics via arc discharge. The pp-HMDSO films were deposited on a soda–lime–silica float glass using HMDSO monomer vapor as a precursor. A detailed surface

  14. Amine Enrichment of Thin-Film Composite Membranes via Low Pressure Plasma Polymerization for Antimicrobial Adhesion.

    Science.gov (United States)

    Reis, Rackel; Dumée, Ludovic F; He, Li; She, Fenghua; Orbell, John D; Winther-Jensen, Bjorn; Duke, Mikel C

    2015-07-15

    Thin-film composite membranes, primarily based on poly(amide) (PA) semipermeable materials, are nowadays the dominant technology used in pressure driven water desalination systems. Despite offering superior water permeation and salt selectivity, their surface properties, such as their charge and roughness, cannot be extensively tuned due to the intrinsic fabrication process of the membranes by interfacial polymerization. The alteration of these properties would lead to a better control of the materials surface zeta potential, which is critical to finely tune selectivity and enhance the membrane materials stability when exposed to complex industrial waste streams. Low pressure plasma was employed to introduce amine functionalities onto the PA surface of commercially available thin-film composite (TFC) membranes. Morphological changes after plasma polymerization were analyzed by SEM and AFM, and average surface roughness decreased by 29%. Amine enrichment provided isoelectric point changes from pH 3.7 to 5.2 for 5 to 15 min of plasma polymerization time. Synchrotron FTIR mappings of the amine-modified surface indicated the addition of a discrete 60 nm film to the PA layer. Furthermore, metal affinity was confirmed by the enhanced binding of silver to the modified surface, supported by an increased antimicrobial functionality with demonstrable elimination of E. coli growth. Essential salt rejection was shown minimally compromised for faster polymerization processes. Plasma polymerization is therefore a viable route to producing functional amine enriched thin-film composite PA membrane surfaces.

  15. Comparative study of structural and optical properties of pulsed and RF plasma polymerized aniline films

    Energy Technology Data Exchange (ETDEWEB)

    Barman, Tapan; Pal, Arup R., E-mail: arpal@iasst.gov.in; Chutia, Joyanti

    2014-09-15

    Graphical abstract: - Highlights: • Pulse DC and RF plasma is used for synthesis of conducting polymer films. • Conjugated structure retention is better at optimum powers in both the processes. • Conjugated structure retention is better in case of RF plasma prepared films. • Band gap is lower in case of RF plasma prepared films at higher power. • Defect in pulse plasma prepared film is less than RF plasma prepared thin films. - Abstract: Plasma polymerization of aniline is carried out by means of continuous RF and pulsed DC glow discharge plasma in a common reactor at different applied powers. The discharge control variables are optimized for good quality film growth and the role of fragmentation of the molecular structure on the structural, optical, morphological and optophysical properties of the deposited plasma polymerized aniline (PPAni) layers is investigated. Retention of the conjugated structure is found to be prominent at optimum applied power to the plasma in both the continuous RF and pulsed DC polymerization techniques. Improvement in conjugated structure and chain length have been observed in both the continuous RF and pulse DC PPAni thin films with the increase in applied power to the plasma up to a certain limit of applied power when working pressure is fixed at 0.15 mbar. A decrease in optical bandgap with the increase in applied power to the plasma is observed in both the pulsed DC and RF PPAni thin films, but it is more significant in case of RF PPAni films. The plasma polymerized aniline thin films are found to emit photoluminescence due to band to band transition and defects generated in the structure.

  16. PLASMA POLYMERIZATION OF HYDROPHILIC AND HYDROPHOBIC MONOMERS FOR SURFACE MODIFICATION OF NUCLE-MICROPOROUS MEMBRANE

    Institute of Scientific and Technical Information of China (English)

    LI Xuefen; LI Zhifen; CHEN Chuanfu; WU Wenhui

    1990-01-01

    Surface modification of nucle-microporous membrane by plasma polymerization of HEMA, NVP and D4 has been studied. The hydrophilicity of membranes was increased with increasing of plasma polymerization time of hydrophilic monomers HEMA and NVP. The flow rate of water through the membrane was increased remarkably after plasma polymerization of HEMA on it.

  17. Solid coatings deposited from liquid methyl methacrylate via Plasma Polymerization

    Science.gov (United States)

    Wurlitzer, Lisa; Maus-Friedrichs, Wolfgang; Dahle, Sebastian

    2016-09-01

    The polymerization of methyl methacrylate via plasma discharges is well known today. Usually, plasma-enhanced chemical vapor deposition (PECVD) is used to deposit polymer coatings. Solid coatings are formed out of the liquid phase from methyl methacrylate via dielectric barrier discharge. The formation of the coating proceeds in the gas and the liquid phase. To learn more about the reactions in the two phases, the coatings from MMA monomer will be compared to those from MMA resin. Finally, attenuated total reflection infrared spectroscopy, confocal laser scanning microscopy and X-ray photoelectron spectroscopy are employed to characterize the solid coatings. In conclusion, the plasma enhanced chemical solution deposition is compared to the classical thermal polymerization of MMA.

  18. Plasma Polymerization Surface Modification of Carbon Black and its Effect in Elastomers

    NARCIS (Netherlands)

    Mathew, T.; Datta, R.N.; Dierkes, W.K.; Talma, A.G.; Ooij, van W.J.; Noordermeer, J.W.M.

    2011-01-01

    Surface modification of carbon black by plasma polymerization was aimed to reduce its surface energy in order to compatibilize the filler with various elastomers. A fullerenic carbon black was used for the modification process. Thermogravimetric analysis, wetting behavior with liquids of known surfa

  19. Sulfonated polystyrene-type plasma-polymerized membranes for miniature direct methanol fuel cells

    Science.gov (United States)

    Roualdes, Stéphanie; Topala, Ionut; Mahdjoub, Habiba; Rouessac, Vincent; Sistat, Philippe; Durand, Jean

    Sulfonated polystyrene-type membranes were synthesized by plasma polymerization of a mixture of styrene and trifluoromethane sulfonic acid monomers in a low-frequency after-glow discharge plasma reactor. Such a deposition process enables the preservation of the monomers structure, which was confirmed by mass spectrometry analysis. The synthesized plasma-polymerized membranes are dense and uniform with a few microns thickness. Their structure determined by Fourier-transform infra-red spectroscopy and X-ray photoelectron spectroscopy is very rich in sulfonic acid groups (up to 5%) and stable up to 120 °C. Even if their intrinsic proton conductivity is low (10 -1 mS cm -1), directly related to their disorganized and highly cross-linked structure, plasma-polymerized membranes present a proton conduction ability similar to Nafion ® because of their low thickness. Due to their highly cross-linked structure, these membranes enable a reduction of the methanol crossover in a factor 10 by comparison with Nafion ®. Thus, the integration of plasma-polymerized films in miniaturized direct methanol fuel cells as proton-exchange membranes seems promising.

  20. Hydrophobic Coatings on Cotton Obtained by in Situ Plasma Polymerization of a Fluorinated Monomer in Ethanol Solutions.

    Science.gov (United States)

    Molina, Ricardo; Teixidó, Josep Maria; Kan, Chi-Wai; Jovančić, Petar

    2017-02-15

    Plasma polymerization using hydrophobic monomers in the gas phase is a well-known technology to generate hydrophobic coatings. However, synthesis of functional hydrophobic coatings using plasma technology in liquids has not yet been accomplished. This work is consequently focused on polymerization of a liquid fluorinated monomer on cotton fabric initiated by atmospheric plasma in a dielectric barrier discharge configuration. Functional hydrophobic coatings on cotton were successfully achieved using in situ atmospheric plasma-initiated polymerization of fluorinated monomer dissolved in ethanol. Gravimetric measurements reveal that the amount of polymer deposited on cotton substrates can be modulated with the concentration of monomer in ethanol solution, and cross-linking reactions occur during plasma polymerization of a fluorinated monomer even without the presence of a cross-linking agent. FTIR and XPS analysis were used to study the chemical composition of hydrophobic coatings and to get insights into the physicochemical processes involved in plasma treatment. SEM analysis reveals that at high monomer concentration, coatings possess a three-dimensional pattern with a characteristic interconnected porous network structure. EDX analysis reveals that plasma polymerization of fluorinated monomers takes place preferentially at the surface of cotton fabric and negligible polymerization takes place inside the cotton fabric. Wetting time measurements confirm the hydrophobicity of cotton coatings obtained although equilibrium moisture content was slightly decreased. Additionally, the abrasion behavior and resistance to washing of plasma-coated cotton has been evaluated.

  1. Atmospheric pressure plasma polymerization using double grounded electrodes with He/Ar mixture

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Ha; Kim, Hyun-Jin; Park, Choon-Sang; Tae, Heung-Sik, E-mail: hstae@ee.knu.ac.kr [School of Electronics Engineering, College of IT Engineering, Kyungpook National University, Daegu, 702-701 (Korea, Republic of); Shin, Bhum Jae [Department of Electronics Engineering, Sejong University, Seoul 143-747 (Korea, Republic of); Seo, Jeong Hyun [Department of Electronics Engineering, Incheon National University, Incheon 406-772 (Korea, Republic of)

    2015-09-15

    In this study, we have proposed the double grounded atmospheric pressure plasma jet (2G-APPJ) device to individually control the plasmas in both fragmentation (or active) and recombination (or passive) regions with a mixture of He and Ar gases to deposit organic thin films on glass or Si substrates. Plasma polymerization of acetone has been successfully deposited using a highly energetic and high-density 2G-APPJ and confirmed by scanning electron microscopy (SEM). Plasma composition was measured by optical emission spectroscopy (OES). In addition to a large number of Ar and He spectra lines, we observed some spectra of C{sub 2} and CH species for fragmentation and N{sub 2} (second positive band) species for recombination. The experimental results confirm that the Ar gas is identified as a key factor for facilitating fragmentation of acetone, whereas the He gas helps the plume of plasma reach the substrate on the 2{sup nd} grounded electrode during the plasma polymerization process. The high quality plasma polymerized thin films and nanoparticles can be obtained by the proposed 2G-APPJ device using dual gases.

  2. Atmospheric pressure plasma polymerization using double grounded electrodes with He/Ar mixture

    Directory of Open Access Journals (Sweden)

    Dong Ha Kim

    2015-09-01

    Full Text Available In this study, we have proposed the double grounded atmospheric pressure plasma jet (2G-APPJ device to individually control the plasmas in both fragmentation (or active and recombination (or passive regions with a mixture of He and Ar gases to deposit organic thin films on glass or Si substrates. Plasma polymerization of acetone has been successfully deposited using a highly energetic and high-density 2G-APPJ and confirmed by scanning electron microscopy (SEM. Plasma composition was measured by optical emission spectroscopy (OES. In addition to a large number of Ar and He spectra lines, we observed some spectra of C2 and CH species for fragmentation and N2 (second positive band species for recombination. The experimental results confirm that the Ar gas is identified as a key factor for facilitating fragmentation of acetone, whereas the He gas helps the plume of plasma reach the substrate on the 2nd grounded electrode during the plasma polymerization process. The high quality plasma polymerized thin films and nanoparticles can be obtained by the proposed 2G-APPJ device using dual gases.

  3. Method of preparing water purification membranes. [polymerization of allyl amine as thin films in plasma discharge

    Science.gov (United States)

    Hollahan, J. R.; Wydeven, T. J., Jr. (Inventor)

    1974-01-01

    Allyl amine and chemically related compounds are polymerized as thin films in the presence of a plasma discharge. The monomer compound can be polymerized by itself or in the presence of an additive gas to promote polymerization and act as a carrier. The polymerized films thus produced show outstanding advantages when used as reverse osmosis membranes.

  4. A plasma polymerization technique to overcome cerebrospinal fluid shunt infections.

    Science.gov (United States)

    Cökeliler, D; Caner, H; Zemek, J; Choukourov, A; Biederman, H; Mutlu, M

    2007-03-01

    Prosthetic devices, mainly shunts, are frequently used for temporary or permanent drainage of cerebrospinal fluid. The pathogenesis of shunt infection is a very important problem in modern medicine and generally this is characterized by staphylococcal adhesion to the cerebrospinal fluid shunt surfaces. In this paper, the prevention of the attachment of test microorganism Staphylococcus epidermidis on the cerebrospinal fluid shunt surfaces by 2-hydroxyethylmethacrylate (HEMA) precursor modification in the plasma polymerization system, is reported. Different plasma polymerization conditions (RF discharge power 10-20-30 W, exposure time 5-10-15 min) were employed during the surface modification. The surface chemistry and topology of unmodified and modified shunts was characterized by x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Also, static contact angle measurements were performed to state the change of surface hydrophilicity. All samples were tested in vitro with Staphylococcus epidermidis. A plasma-polymerized HEMA film (PP HEMA) was found to be an alternative simple method to decrease the microorganism attachment and create bacterial anti-fouling surfaces. The attachment of the model microorganism Staphylococcus epidermidis on the shunt surface modified by PP HEMA at 20 W and 15 min was reduced 62.3% if compared to the unmodified control surface of the shunt.

  5. A plasma polymerization technique to overcome cerebrospinal fluid shunt infections

    Energy Technology Data Exchange (ETDEWEB)

    Coekeliler, D [Plasma Aided Bioengineering and Biotechnology Research Laboratory, Engineering Faculty, Hacettepe University, 06532, Ankara (Turkey); Caner, H [Department of Neurosurgery, School of Medicine, Baskent University, 06610, Ankara (Turkey); Zemek, J [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 162 53, Prague, Czech Republic (Czech Republic); Choukourov, A [Department of Macromolecular Physics, Charles University, V Holesovickach 2, 18000 Prague (Czech Republic); Biederman, H [Department of Macromolecular Physics, Charles University, V Holesovickach 2, 18000 Prague (Czech Republic); Mutlu, M [Plasma Aided Bioengineering and Biotechnology Research Laboratory, Engineering Faculty, Hacettepe University, 06532, Ankara (Turkey)

    2007-03-01

    Prosthetic devices, mainly shunts, are frequently used for temporary or permanent drainage of cerebrospinal fluid. The pathogenesis of shunt infection is a very important problem in modern medicine and generally this is characterized by staphylococcal adhesion to the cerebrospinal fluid shunt surfaces. In this paper, the prevention of the attachment of test microorganism Staphylococcus epidermidis on the cerebrospinal fluid shunt surfaces by 2-hydroxyethylmethacrylate (HEMA) precursor modification in the plasma polymerization system, is reported. Different plasma polymerization conditions (RF discharge power 10-20-30 W, exposure time 5-10-15 min) were employed during the surface modification. The surface chemistry and topology of unmodified and modified shunts was characterized by x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Also, static contact angle measurements were performed to state the change of surface hydrophilicity. All samples were tested in vitro with Staphylococcus epidermidis. A plasma-polymerized HEMA film (PP HEMA) was found to be an alternative simple method to decrease the microorganism attachment and create bacterial anti-fouling surfaces. The attachment of the model microorganism Staphylococcus epidermidis on the shunt surface modified by PP HEMA at 20 W and 15 min was reduced 62.3% if compared to the unmodified control surface of the shunt.

  6. Plasma-induced polymerization for enhancing paper hydrophobicity.

    Science.gov (United States)

    Song, Zhaoping; Tang, Jiebin; Li, Junrong; Xiao, Huining

    2013-01-30

    Hydrophobic modification of cellulose fibers was conducted via plasma-induced polymerization in an attempt to graft the hydrophobic polymer chains on paper surface, this increasing the hydrophobicity of paper. Two hydrophobic monomers, butyl acrylate (BA) and 2-ethylhexyl acrylate (2-EHA), were grafted on cellulose fibers, induced by atmospheric cold plasma. Various influencing factors associated with the plasma-induced grafting were investigated. Contact-angle measurement, Fourier Transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) were used to ascertain the occurrence of the grafting and characterized the changes of the cellulose fiber after modification. The results showed that the hydrophobicity of the modified paper sheet was improved significantly after the plasma-induced grafting. The water contact angle on the paper surface reached up to 130°. The morphological differences between modified and unmodified samples were also revealed by SEM observation. The resulting paper is promising as a green-based packaging material.

  7. Modulation of release kinetics by plasma polymerization of ampicillin-loaded β-TCP ceramics

    Science.gov (United States)

    Labay, C.; Buxadera-Palomero, J.; Avilés, M.; Canal, C.; Ginebra, M. P.

    2016-08-01

    Beta-tricalcium phosphate (β-TCP) bioceramics are employed in bone repair surgery. Their local implantation in bone defects puts them in the limelight as potential materials for local drug delivery. However, obtaining suitable release patterns fitting the required therapeutics is a challenge. Here, plasma polymerization of ampicillin-loaded β-TCP is studied for the design of a novel antibiotic delivery system. Polyethylene glycol-like (PEG-like) coating of β-TCP by low pressure plasma polymerization was performed using diglyme as precursor, and nanometric PEG-like layers were obtained by simple and double plasma polymerization processes. A significant increase in hydrophobicity, and the presence of plasma polymer was visible on the surface by SEM and quantified by XPS. As a main consequence of the plasma polymerisation, the release kinetics were successfully modified, avoiding burst release, and slowing down the initial rate of release leading to a 4.5 h delay in reaching the same antibiotic release percentage, whilst conservation of the activity of the antibiotic was simultaneously maintained. Thus, plasma polymerisation on the surface of bioceramics may be a good strategy to design controlled drug delivery matrices for local bone therapies.

  8. Plasma processing for VLSI

    CERN Document Server

    Einspruch, Norman G

    1984-01-01

    VLSI Electronics: Microstructure Science, Volume 8: Plasma Processing for VLSI (Very Large Scale Integration) discusses the utilization of plasmas for general semiconductor processing. It also includes expositions on advanced deposition of materials for metallization, lithographic methods that use plasmas as exposure sources and for multiple resist patterning, and device structures made possible by anisotropic etching.This volume is divided into four sections. It begins with the history of plasma processing, a discussion of some of the early developments and trends for VLSI. The second section

  9. Core/shell silicon/polyaniline particles via in-flight plasma-induced polymerization

    Science.gov (United States)

    Yasar-Inceoglu, Ozgul; Zhong, Lanlan; Mangolini, Lorenzo

    2015-08-01

    Although silicon nanoparticles have potential applications in many relevant fields, there is often the need for post-processing steps to tune the property of the nanomaterial and to optimize it for targeted applications. In particular surface modification is generally necessary to both tune dispersibility of the particles in desired solvents to achieve optimal coating conditions, and to interface the particles with other materials to realize functional heterostructures. In this contribution we discuss the realization of core/shell silicon/polymer nanoparticles realized using a plasma-initiated in-flight polymerization process. Silicon particles are produced in a non-thermal plasma reactor using silane as a precursor. After synthesis they are aerodynamically injected into a second plasma reactor into which aniline vapor is introduced. The second plasma initiates the polymerization reactor leading to the formation of a 3-4 nm thick polymer shell surrounding the silicon core. The role of processing conditions on the properties of the polymeric shell is discussed. Preliminary results on the testing of this material as an anode for lithium ion batteries are presented.

  10. Plasma Micro-Nanotextured, Scratch, Water and Hexadecane Resistant, Superhydrophobic, and Superamphiphobic Polymeric Surfaces with Perfluorinated Monolayers

    NARCIS (Netherlands)

    Ellinas, K.; Pujari, S.P.; Dragatogiannis, D.A.; Charitidis, C.A.; Tserepi, A.; Zuilhof, H.; Gogolides, E.

    2014-01-01

    Superhydrophobic and superamphiphobic toward superoleophobic polymeric surfaces of polymethyl methacrylate (PMMA), polyether ether ketone (PEEK), and polydimethyl siloxane (PDMS) are fabricated in a two-step process: (1) plasma texturing (i.e., ion-enhanced plasma etching with simultaneous roughenin

  11. Wettability, optical properties and molecular structure of plasma polymerized diethylene glycol dimethyl ether

    Energy Technology Data Exchange (ETDEWEB)

    Azevedo, T C A M; Algatti, M A; Mota, R P; Honda, R Y; Kayama, M E; Kostov, K G; Fernandes, R S [FEG-DFQ-UNESP, Av. Ariberto Pereira da Cunha 333, 12516-410 - Guaratingueta, SP (Brazil); Cruz, N C; Rangel, E C, E-mail: algatti@feg.unesp.b [UNESP, Avenida Tres de Marco, 511, 18087-180 Sorocaba, SP (Brazil)

    2009-05-01

    Modern industry has frequently employed ethylene glycol ethers as monomers in plasma polymerization process to produce different types of coatings. In this work we used a stainless steel plasma reactor to grow thin polymeric films from low pressure RF excited plasma of diethylene glycol dimethyl ether. Plasmas were generated at 5W RF power in the range of 16 Pa to 60 Pa. The molecular structure of plasma polymerized films and their optical properties were analyzed by Fourier Transform Infrared Spectroscopy (FTIR) and Ultraviolet-Visible Spectroscopy, respectively. The IR spectra show C-H stretching at 3000-2900 cm{sup -1}, C=O stretching at 1730-1650 cm{sup -1}, C-H bending at 1440-1380 cm{sup -1}, C-O and C-O-C stretching at 1200-1000 cm{sup -1}. The refraction index was around 1.5 and the optical gap calculated from absorption coefficient presented value near 3.8 eV. Water contact angle of the films ranged from 40 deg. to 35 deg. with corresponding surface energy from 66 to 73x10{sup -7} J. Because of its favorable optical and hydrophilic characteristics these films can be used in ophthalmic industries as glass lenses coatings.

  12. Characterization of Plasma-Polymerized Fused Polycyclic Compounds for Binding Conducting Polymers

    DEFF Research Database (Denmark)

    Winther-Jensen, Bjørn; Norrman, Kion; Kingshott, Peter

    2005-01-01

    An investigation is made of the plasma polymerization of fused polycyclic monomers containing a dioxy-ring that is fused to an aromatic ring. These molecules provide the basis for very efficient polymerization mechanisms in which only the dioxy-ring undergoes ring opening during the polymerization...... with the remaining part of the monomer remaining intact. XPS, ToF-SIMS, and IR are used to investigate the chemistry of the films produced by plasma polymerization of EDT, which contains a high content of the aromatic group. We find that the plasma-polymerized films of EDT contain intact thiophene groups...

  13. Blood compatibility of surface modified poly(ethylene terephthalate) (PET) by plasma polymerized acetobromo-alpha-D-glucose.

    Science.gov (United States)

    Kumar, D Sakthi; Nair, Baiju G; Varghese, Saino H; Nair, Remya; Hanajiri, T; Maekawa, T; Yoshida, Yasuhiko; John, Rajan K; Jayakrishnan, A

    2010-02-01

    Poly (ethylene terephthalate) (PET) was surface modified by plasma polymerization of acetobromo-alpha-D-glucose (ABG) at different radio frequency (RF) powers. Plasma polymerization was carried out by vaporizing ABG in the powder form by heating at 135 degrees C. Surface modification resulted in improved hydrophilicity and smoothness of the surface especially at low RF powers (30-50 W), but at high RF powers, the surface was found to be etched and the hydrophilicity decreased as evidenced by atomic force microscopy (AFM) and contact angle measurements. The plasma polymerized ABG film was found to be extensively cross-linked as evidenced by its insolubility in water. Infra red (IR) and X-ray photoelectron spectroscopy (XPS) were employed to characterize the plasma polymerized ABG films. IR studies revealed that at lower RF powers, polymerization was taking place mainly by breaking up of acetoxy group while retaining the ring structures to a major extent during the polymerization process whereas at high RF powers, the rupture of ring structures was indicated. XPS indicated a reduction in the percentage of oxygen in the polymers going from low to high RF powers suggestive of complete destruction of the acetoxy group at high RF powers. Cross-cut tests showed excellent adhesive properties of the plasma polymerized ABG films onto PET. Static platelet adhesion tests using platelet rich human plasma showed significantly reduced adhesion of platelets onto modified PET surface as evidenced by scanning electron microscopy. Polymerization of glucose and its derivatives using RF plasma has not been reported so far and the preliminary results reported in this study shows that this could be an interesting approach in the surface modification of biomaterials.

  14. Hydrophobic plasma polymerized hexamethyldisilazane thin films: characterization and uses

    Directory of Open Access Journals (Sweden)

    Alexsander Tressino de Carvalho

    2006-03-01

    Full Text Available Hexametildisilazane (HMDS plasma polymerized thin films obtained using low frequency power supplies can be used to make adsorbent films and turn surfaces hydrophobic. The aim of this work was to verify the hydrophobicity and adsorption properties of HMDS thin films (with and without the addition of oxygen, resulting in double or single layer films obtained using an inductive reactor powered with a 13.56 MHz power supply. Single and double layer thin films were deposited on silicon for film characterization, polypropylene (PP for ultraviolet (UVA/UVC resistance tests, piezoelectric quartz crystal for adsorption tests. The double layer (intermixing of HMDS plasma polymerized films and HMDS plasma oxidized surfaces showed a non-continuous layer. The films showed good adhesion to all substrates. Infrared analysis showed the presence of CHn, SiCH3, SiNSi and SiCH2Si within the films. Contact angle measurements with water showed hydrophobic surfaces. UVA/UVC exposure of the films resulted in the presence of cross-linking on carbonic radicals and SiCH2Si formation, which resulted in a possible protection of PP against UVA/UVC for a duration of up to two weeks. Adsorption tests showed that all organic reactants were adsorbed but not water. Plasma etching (PE using O2 showed that even after 15 minutes of exposure the films do not change their hydrophobic characteristic but were oxidized. The results point out that HMDS films can be used: for ultraviolet protection of flexible organic substrates, such as PP, for sensor and/or preconcentrator development, due to their adsorption properties, and in spatial applications due to resistance for O2 attack in hostile conditions, such as plasma etching.

  15. Surface modification by plasma polymerization: film deposition, tailoring of surface properties and biocompatibility

    OpenAIRE

    Os, van, J.

    2000-01-01

    The work described in this thesis concerns the surface modification of materials by thin film deposition in a plasma reactor. In particular, thin polymeric films bearing amine functionalities were synthesized by plasma polymerization of amino group containing monomers. In addition to the synthesis, attention was directed towards the characterization of these films, and the tailoring of their surface properties on a molecular level. Finally, the amino groups introduced by plasma polymerization...

  16. A Novel Continuously Initiated Polymerization by One-Atmosphere Low Temperature Plasma Device

    Institute of Scientific and Technical Information of China (English)

    You qingliang; Meng yuedong; Wang jianhua; Ou qiongrong; Xu xu; Zhong shaofeng

    2005-01-01

    A novel atmospheric plasma device developed in this paper, which is more effective and convenient to study the plasma-initiated polymerization (PIP) than conventional setup. The structure and mechanism of the device is introduced. Some plasma-initiated polymerization experiments are carried out on the device, and the conversion of AA (Acrylic acid) and AM (Acryl amide) atmospheric (N2) plasma polymerization are respectively 89% and 94% after 120 h post polymerization, whereby IR spectra of the product (AA, AM). Our PIP result are confirmed.

  17. Grafting of molecularly imprinted polymer to porous polyethylene filtration membranes by plasma polymerization.

    Science.gov (United States)

    Cowieson, D; Piletska, E; Moczko, E; Piletsky, S

    2013-08-01

    An application of plasma-induced grafting of polyethylene membranes with a thin layer of molecularly imprinted polymer (MIP) was presented. High-density polyethylene (HDPE) membranes, "Vyon," were used as a substrate for plasma grafting modification. The herbicide atrazine, one of the most popular targets of the molecular imprinting, was chosen as a template. The parameters of the plasma treatment were optimized in order to achieve a good balance between polymerization and ablation processes. Modified HDPE membranes were characterized, and the presence of the grafted polymeric layer was confirmed based on the observed weight gain, pore size measurements, and infrared spectrometry. Since there was no significant change in the porosity of the modified membranes, it was assumed that only a thin layer of the polymer was introduced on the surface. The experiments on the re-binding of the template atrazine to the membranes modified with MIP and blank polymers were performed. HDPE membranes which were grafted with polymer using continuous plasma polymerization demonstrated the best result which was expressed in an imprinted factor equal to 3, suggesting that molecular imprinting was successfully achieved.

  18. Comparative study of nanocomposites prepared by pulsed and dc sputtering combined with plasma polymerization suitable for photovoltaic device applications

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, Amreen A. [Physical Sciences Division, Institute of Advanced Study in Science and Technology, Guwahati, Assam (India); Pal, Arup R., E-mail: arpal@iasst.gov.in [Physical Sciences Division, Institute of Advanced Study in Science and Technology, Guwahati, Assam (India); Kar, Rajib [Laser and Plasma Technology Division, Bhabha Atomic Research Center, Trombay, Mumbai (India); Bailung, Heremba; Chutia, Joyanti [Physical Sciences Division, Institute of Advanced Study in Science and Technology, Guwahati, Assam (India); Patil, Dinkar S. [Laser and Plasma Technology Division, Bhabha Atomic Research Center, Trombay, Mumbai (India)

    2014-12-15

    Plasma processing, a single step method for production of large area composite films, is employed to deposit plasma polymerized aniline-Titanium dioxide (PPani-TiO{sub 2}) nanocomposite thin films. The deposition of PPani-TiO{sub 2} nanocomposite films are made using reactive magnetron sputtering and plasma polymerization combined process. This study focuses on the direct comparison between continuous and pulsed dc magnetron sputtering techniques of titanium in combination with rf plasma polymerization of aniline. The deposited PPani-TiO{sub 2} nanocomposite films are characterized and discussed in terms of structural, morphological and optical properties. A self powered hybrid photodetector has been developed by plasma based process. The proposed method provides a new route where the self-assembly of molecules, that is, the spontaneous association of atomic or molecular building blocks under plasma environment, emerge as a successful strategy to form well-defined structural and morphological units of nanometer dimensions. - Highlights: • PPani-TiO{sub 2} nanocomposite by pulsed and dc sputtering with rf plasma polymerization. • In-situ and Ex-situ H{sub 2}SO{sub 4} doping in PPani-TiO{sub 2} nanocomposite. • PPani-TiO{sub 2} nanocomposite based self-powered-hybrid photodetector.

  19. Plasma-polymerized thiophene films for enhanced rubber steel bonding

    Science.gov (United States)

    Delattre, James L.; d'Agostino, Riccardo; Fracassi, Francesco

    2006-03-01

    Thin films of plasma-polymerized thiophene (PPTh) were deposited on cold-rolled steel substrates to improve adhesion to rubber compounds. PPTh films were characterized by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy (FT-IR) and atomic force microscopy. The ratio of carbon-to-sulfur found in PPTh films is 4:1, suggesting the monomer structure is generally intact, which was supported by FT-IR absorptions characteristic of polymerized thiophene rings. However, some fragmentation did occur to give acetylenic and aliphatic groups. Steel-rubber adhesion measurements, performed in accordance with the ASTM 429-B peel test, strongly depended on cleaning and pretreatment methods as well as film thickness. Best results were obtained on polished steel samples that were cleaned with acid, pretreated with a hydrogen/argon plasma, then coated with 50 Å of PPTh film. These samples exhibited a peel force of 14.3 N/mm, which is comparable to that of polished brass control samples. Depth-profiling XPS analysis of the rubber-steel interface showed the existence of an iron sulfide layer which is likely responsible for the strong adhesion.

  20. Graft polymerization and plasma treatment of polymer membranes for fouling reduction: a review.

    Science.gov (United States)

    Kochkodan, Victor M; Sharma, Virender K

    2012-01-01

    This article presents a review of recent developments in surface modification of polymer membranes via graft polymerization and plasma treatment for reduction of fouling with organic compounds and microorganisms in pressure driven membrane processes. The factors affecting membrane fouling, such as membrane hydrophilicity, charge and surface roughness are discussed. The recent studies in which the reduction of organic fouling and biofouling by the modification of the membrane surface via ultraviolet/redox initiated surface grafting of hydrophilic polymers and low temperature plasma treatment are reviewed.

  1. Surface modification of nanoporous alumina membranes by plasma polymerization.

    Science.gov (United States)

    Losic, Dusan; Cole, Martin A; Dollmann, Björn; Vasilev, Krasimir; Griesser, Hans J

    2008-06-18

    The deposition of plasma polymer coatings onto porous alumina (PA) membranes was investigated with the aim of adjusting the surface chemistry and the pore size of the membranes. PA membranes from commercial sources with a range of pore diameters (20, 100 and 200 nm) were used and modified by plasma polymerization using n-heptylamine (HA) monomer, which resulted in a chemically reactive polymer surface with amino groups. Heptylamine plasma polymer (HAPP) layers with a thickness less than the pore diameter do not span the pores but reduce their diameter. Accordingly, by adjusting the deposition time and thus the thickness of the plasma polymer coating, it is feasible to produce any desired pore diameter. The structural and chemical properties of modified membranes were studied by scanning electron microscopy (SEM), atomic force microscopy (AFM) and x-ray electron spectroscopy (XPS). The resultant PA membranes with specific surface chemistry and controlled pore size are applicable for molecular separation, cell culture, bioreactors, biosensing, drug delivery, and engineering complex composite membranes.

  2. Surface modification by plasma polymerization: film deposition, tailoring of surface properties and biocompatibility

    NARCIS (Netherlands)

    Os, van Menno Thomas

    2000-01-01

    The work described in this thesis concerns the surface modification of materials by thin film deposition in a plasma reactor. In particular, thin polymeric films bearing amine functionalities were synthesized by plasma polymerization of amino group containing monomers. In addition to the synthesis,

  3. Origins and Development of Initiation of Free Radical Polymerization Processes

    Directory of Open Access Journals (Sweden)

    Dietrich Braun

    2009-01-01

    Full Text Available At present worldwide about 45% of the manufactured plastic materials and 40% of synthetic rubber are obtained by free radical polymerization processes. The first free radically synthesized polymers were produced between 1910 and 1930 by initiation with peroxy compounds. In the 1940s the polymerization by redox processes was found independently and simultaneously at IG Farben in Germany and ICI in Great Britain. In the 1950s the systematic investigation of azo compounds as free radical initiators followed. Compounds with labile C–C-bonds were investigated as initiators only in the period from the end of the 1960s until the early 1980s. At about the same time, iniferters with cleavable S–S-bonds were studied in detail. Both these initiator classes can be designated as predecessors for “living” or controlled free radical polymerizations with nitroxyl-mediated polymerizations, reversible addition fragmentation chain transfer processes (RAFT, and atom transfer radical polymerizations (ATRP.

  4. Plasma polymerized epoxide functional surfaces for DNA probe immobilization.

    Science.gov (United States)

    Chu, Li-Qiang; Knoll, Wolfgang; Förch, Renate

    2008-09-15

    The development of functional surfaces for the immobilization of DNA probe is crucial for a successful design of a DNA sensor. In this report, epoxide functional thin films were achieved simply by pulsed plasma polymerization (PP) of glycidyl methacrylate (GMA) at low duty cycle. The presence of epoxide groups in the resulting ppGMA films was confirmed by Fourier transform infrared spectroscopy. The ppGMA coatings were found to be resistant to the non-specific adsorption of DNA strands, while the epoxide groups obtained could react with amine-modified DNA probes in a mild basic environment without any activation steps. A DNA sensor was made, and was successfully employed to distinguish different DNA sequences with one base pair mismatch as seen by surface plasmon enhanced fluorescence spectroscopy (SPFS). The regeneration of the present DNA sensor was also discussed. This result suggests that surface modification with ppGMA films is very promising for the fabrication of various DNA sensors.

  5. Study of plasma-induced graft polymerization of stearyl methacrylate on cotton fabric substrates

    Science.gov (United States)

    Li, Yongqiang; Zhang, Yan; Zou, Chao; Shao, Jianzhong

    2015-12-01

    A simple and facile method to prepare the cotton fabric with hydrophobicity was described in the present work. In the one-step process, the cotton fabric pre-impregnated with the monomer solution of stearyl methacrylate (SMA) was placed in the plasma chamber and followed by glow discharge of the Helium low temperature plasma. The cotton fabrics before and after the plasma treatment were characterized by field emission scanning electron microscopy (FESEM), infrared spectroscopic analysis (FTIR), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA), respectively. The wettability of the cotton fabrics was evaluated by contact angle measurement. Fabric Hand Values and mechanical properties were also measured in the experiment. The results showed that polymer films could be coated on the cotton fibers through the plasma induced grafting polymerization of SMA. The modified cotton fabrics exhibited an extraordinary hydrophobicity with a contact angle of 149° for a 5 μL water droplet and excellent thermal stability. The relative hand value and mechanical breaking strength of the cotton fabrics declined slightly after graft polymerization of SMA by the plasma.

  6. Synthesis and Characterization of Nanofibrous Polyaniline Thin Film Prepared by Novel Atmospheric Pressure Plasma Polymerization Technique

    Directory of Open Access Journals (Sweden)

    Choon-Sang Park

    2016-01-01

    Full Text Available This work presents a study on the preparation of plasma-polymerized aniline (pPANI nanofibers and nanoparticles by an intense plasma cloud type atmospheric pressure plasma jets (iPC-APPJ device with a single bundle of three glass tubes. The nano size polymer was obtained at a sinusoidal wave with a peak value of 8 kV and a frequency of 26 kHz under ambient air. Discharge currents, photo-sensor amplifier, and optical emission spectrometer (OES techniques were used to analyze the plasma produced from the iPC-APPJ device. Field emission scanning electron microscopy (FE-SEM, transmission electron microscopy (TEM, Fourier transform infrared spectroscopy (FT-IR, gas chromatography-mass spectrometry (GC-MS, and gel permeation chromatography (GPC techniques were used to analyze the pPANI. FE-SEM and TEM results show that pPANI has nanofibers, nanoparticles morphology, and polycrystalline characteristics. The FT-IR and GC-MS analysis show the characteristic polyaniline peaks with evidence that some quinone and benzene rings are broken by the discharge energy. GPC results show that pPANI has high molecular weight (Mw, about 533 kDa with 1.9 polydispersity index (PDI. This study contributes to a better understanding on the novel growth process and synthesis of uniform polyaniline nanofibers and nanoparticles with high molecular weights using the simple atmospheric pressure plasma polymerization technique.

  7. Polymerization by plasma: surface treatment and plasma simulation; Polimerizacion por plasma: tratamiento superficial y simulacion del plasma

    Energy Technology Data Exchange (ETDEWEB)

    Morales C, J

    2001-07-01

    One of the general objectives that are developed by the group of polymers semiconductors in the laboratory of polymers of the UAM-Iztapalapa is to study the surface treatment for plasma of different materials. Framed in this general objective, in this work three lines of investigation have been developed, independent one of other that converge in the general objective. The first one tries about the modeling one and evaluation of the microscopic parameters of operation of the polymerization reactor. The second are continuation of the study of conductive polymers synthesized by plasma and the third are an application of the treatment for plasma on natural fibers. In the first one it lines it is carried out the characterization and simulation of the parameters of operation of the polymerization reactor for plasma. They are determined the microscopic parameters of operation of the reactor experimentally like they are the electronic temperature, the potential of the plasma and the density average of electrons using for it an electrostatic Langmuir probe. In the simulation, starting from the Boltzmann transport equation it thinks about the flowing pattern and the electronic temperature, the ions density is obtained and of electrons. The data are compared obtained experimentally with the results of the simulation. In second line a study is presented about the influence of the temperature on the electric conductivity of thin films doped with iodine, of poly aniline (P An/I) and poly pyrrole (P Py/I). The films underwent heating-cooling cycles. The conductivity of P An/I and P Py/I in function of the temperature it is discussed based on the Arrhenius model, showing that it dominates the model of homogeneous conductivity. It is also synthesized a polymer bi-layer of these two elements and a copolymer random poly aniline-poly pyrrole, of the first one it the behavior of its conductivity discusses with the temperature and of the second, the conductivity is discussed in

  8. Initial biocompatibility of plasma polymerized hexamethyldisiloxane films with different wettability

    Energy Technology Data Exchange (ETDEWEB)

    Krasteva, N A; Toromanov, G; Hristova, K T; Radeva, E I; Pecheva, E V; Dimitrova, R P; Altankov, G P; Pramatarova, L D, E-mail: nataly@bio21.bas.b

    2010-11-01

    Understanding the relationships between material surface properties, behaviour of adsorbed proteins and cellular responses is essential to design optimal material surfaces for tissue engineering. In this study we modify thin layers of plasma polymerized hexamethyldisiloxane (PPHMDS) by ammonia treatment in order to increase surface wettability and the corresponding biological response. The physico-chemical properties of the polymer films were characterized by contact angle (CA) measurements and Fourier Transform Infrared Spectroscopy (FTIR) analysis.Human umbilical vein endothelial cells (HUVEC) were used as model system for the initial biocompatibility studies following their behavior upon preadsorption of polymer films with three adhesive proteins: fibronectin (FN), fibrinogen (FG) and vitronectin (VN). Adhesive interaction of HUVEC was evaluated after 2 hours by analyzing the overall cell morphology, and the organization of focal adhesion contacts and actin cytoskeleton. We have found similar good cellular response on FN and FG coated polymer films, with better pronounced vinculin expression on FN samples while. Conversely, on VN coated surfaces the wettability influenced significantly initial celular interaction spreading. The results obtained suggested that ammonia plasma treatment can modulate the biological activity of the adsorbed protein s on PPHMDS surfaces and thus to influence the interaction with endothelial cells.

  9. Plasma polymerization of acrylic acid onto polystyrene by cyclonic plasma at atmospheric pressure

    Science.gov (United States)

    Chang, Yi-Jan; Lin, Chin-Ho; Huang, Chun

    2016-01-01

    The cyclonic atmospheric-pressure plasma is developed for chamberless deposition of poly(acrylic acid) film from argon/acrylic acid mixtures. The photoemission plasma species in atmospheric-pressure plasma polymerization was identified by optical emission spectroscopy (OES). The OES diagnosis data and deposition results indicated that in glow discharge, the CH and C2 species resulted from low-energy electron-impact dissociation that creates deposition species, but the strong CO emission lines are related to nondeposition species. The acrylic acid flow rate is seen as the key factor affecting the film growth. The film surface analysis results indicate that a smooth, continuous, and uniform surface of poly(acrylic acid) films can be formed at a relatively low plasma power input. This study reveals the potential of chamberless film growth at atmospheric pressure for large-area deposition of poly(acrylic acid) films.

  10. Surface modification of cellulosic substrates via atmospheric pressure plasma polymerization of acrylic acid: Structure and properties

    Science.gov (United States)

    Garcia-Torres, Jose; Sylla, Dioulde; Molina, Laura; Crespo, Eulalia; Mota, Jordi; Bautista, Llorenç

    2014-06-01

    Surface chemical modification of cellulose-based substrates has been carried out by atmospheric pressure plasma enhanced chemical vapor deposition (AP-PECVD) of acrylic acid. The structure/properties relationship of the samples was studied as a function of the plasma experimental conditions. Acrylic acid monomer/helium ratio and treatment speed clearly influences the wettability properties of the paper substrate: advancing contact angle values were reduced to the half if compare to non-treated paper. Surface morphology of the films did not greatly vary at short polymerization times but fibers were covered by a poly(acrylic acid) film at longer times. FTIR and XPS techniques allowed detecting the retention of carboxylic acid groups/moieties. The possibility to quickly design architectures with tunable carboxylic functions by modifying the plasma processing parameters is shown.

  11. Controllable surface morphology and properties via mist polymerization on a plasma-treated polymethyl methacrylate surface.

    Science.gov (United States)

    Wan, S J; Wang, L; Xu, X J; Zhao, C H; Liu, X D

    2014-02-14

    Surface modification by grafting polymers on solid materials is an important strategy used to improve surface properties. This article reports that under appropriate conditions, very thin layers with desired morphologies may be constructed on a plasma-treated substrate by feeding a small quantity of a monomer with a mist stream carrying droplets produced from monomer solutions. We investigate the effects of process parameters that affect layer morphology, including exposure time to the mist stream, concentration of the monomer solution, and solvent selectivity. For a methyl methacrylate solution in ethanol, nanoparticles are uniformly grown with increasing monomer concentration or exposure time and finally form a porous layer at 3.65 mol L(-1) for 30 min. Decreasing solvent polarity not only affects surface morphology, but also increases hydrophobicity of the resulting surface. With 2,2,3,4,4,4-hexafluorobutyl methacrylate as the monomer, SEM and AFM micrographs indicated that mist polymerization results in numerous microspheres on the activated surface. These experimental results were interpreted by a mechanism in terms of an in situ polymerization accompanied by a phase transformation of the resulting polymer. Specifically, plasma treatment provides highly active cations and radicals to initiate very rapid polymerization, and the resulting polymers are consequently deposited from the liquid onto the surface under phase transition mechanisms.

  12. Investigation of Plasma Polymerized Maleic Anhydride Film in a Middle Frequency Dielectric Barrier Discharge

    Institute of Scientific and Technical Information of China (English)

    TANG Wenjie; CHEN Qiang; ZHANG Yuefei; GE Yuanjing

    2008-01-01

    Plasma polymerized maleic anhydride (MA) was carried out by using maleic anhydride supersaturated ethanol solution as a precursor in a dielectric barrier discharge (DBD). The film properties were characterized by water contact angle (WCA), Fourier transfer infrared (FTIR), X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM) analysis, and a thickness profilometer. The influence of the processing parameters on the film properties such as the power frequency, and polymerization zone was investigated. The results show that anhydride group incorporated into the growing films is favorable at the frequency of 80 kHz and working pressure of 50 Pa. The poly (maleic anhydride) film is uniform and compact at an average deposition rate of 8 nm/min.

  13. Micro patterning of cell and protein non-adhesive plasma polymerized coatings for biochip applications

    DEFF Research Database (Denmark)

    Bouaidat, Salim; Berendsen, C.; Thomsen, P.;

    2004-01-01

    Micro scale patterning of bioactive surfaces is desirable for numerous biochip applications. Polyethyleneoxide-like (PEO-like) coating with non-fouling functionality has been deposited using low frequency AC plasma polymerization. The non-fouling properties of the coating were tested with human...... cells ( HeLa) and fluorescence labeled proteins (isothiocyanate-labeled bovine serum albumin, i.e. FITC-BSA). The PEO-like coatings were fabricated by plasma polymerization of 12-crown-4 (ppCrown) with plasma polymerized hexene (ppHexene) as adhesion layer. The coatings were micro patterned using...

  14. Conductive Polymer Synthesis with Single-Crystallinity via a Novel Plasma Polymerization Technique for Gas Sensor Applications

    Directory of Open Access Journals (Sweden)

    Choon-Sang Park

    2016-09-01

    Full Text Available This study proposes a new nanostructured conductive polymer synthesis method that can grow the single-crystalline high-density plasma-polymerized nanoparticle structures by enhancing the sufficient nucleation and fragmentation of the pyrrole monomer using a novel atmospheric pressure plasma jet (APPJ technique. Transmission electron microscopy (TEM, Fourier transform infrared spectroscopy (FT-IR, X-ray photoelectron spectroscopy (XPS, and field emission scanning electron microscopy (FE-SEM results show that the plasma-polymerized pyrrole (pPPy nanoparticles have a fast deposition rate of 0.93 µm·min−1 under a room-temperature process and have single-crystalline characteristics with porous properties. In addition, the single-crystalline high-density pPPy nanoparticle structures were successfully synthesized on the glass, plastic, and interdigitated gas sensor electrode substrates using a novel plasma polymerization technique at room temperature. To check the suitability of the active layer for the fabrication of electrochemical toxic gas sensors, the resistance variations of the pPPy nanoparticles grown on the interdigitated gas sensor electrodes were examined by doping with iodine. As a result, the proposed APPJ device could obtain the high-density and ultra-fast single-crystalline pPPy thin films for various gas sensor applications. This work will contribute to the design of highly sensitive gas sensors adopting the novel plasma-polymerized conductive polymer as new active layer.

  15. Surface modification of polymeric materials by cold atmospheric plasma jet

    Science.gov (United States)

    Kostov, K. G.; Nishime, T. M. C.; Castro, A. H. R.; Toth, A.; Hein, L. R. O.

    2014-09-01

    In this work we report the surface modification of different engineering polymers, such as, polyethylene terephthalate (PET), polyethylene (PE) and polypropylene (PP) by an atmospheric pressure plasma jet (APPJ). It was operated with Ar gas using 10 kV, 37 kHz, sine wave as an excitation source. The aim of this study is to determine the optimal treatment conditions and also to compare the polymer surface modification induced by plasma jet with the one obtained by another atmospheric pressure plasma source - the dielectric barrier discharge (DBD). The samples were exposed to the plasma jet effluent using a scanning procedure, which allowed achieving a uniform surface modification. The wettability assessments of all polymers reveal that the treatment leads to reduction of more than 40° in the water contact angle (WCA). Changes in surface composition and chemical bonding were analyzed by x-ray photoelectron spectroscopy (XPS) and Fourier-Transformed Infrared spectroscopy (FTIR) that both detected incorporation of oxygen-related functional groups. Surface morphology of polymer samples was investigated by Atomic Force Microscopy (AFM) and an increase of polymer roughness after the APPJ treatment was found. The plasma-treated polymers exhibited hydrophobic recovery expressed in reduction of the O-content of the surface upon rinsing with water. This process was caused by the dissolution of low molecular weight oxidized materials (LMWOMs) formed on the surface as a result of the plasma exposure.

  16. Surface modification of polymeric materials by cold atmospheric plasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Kostov, K.G., E-mail: kostov@feg.unesp.br [Faculty of Engineering in Guaratinguetá–FEG, Universidade Estadual Paulista–UNESP Guaratiguetá, 12516-410, SP (Brazil); Nishime, T.M.C.; Castro, A.H.R. [Faculty of Engineering in Guaratinguetá–FEG, Universidade Estadual Paulista–UNESP Guaratiguetá, 12516-410, SP (Brazil); Toth, A. [Institute of Material and Environmental Chemistry, Hungarian Academy of Science P.O. Box 17, H-1525, Budapest (Hungary); Hein, L.R.O. [Faculty of Engineering in Guaratinguetá–FEG, Universidade Estadual Paulista–UNESP Guaratiguetá, 12516-410, SP (Brazil)

    2014-09-30

    Highlights: • We investigate polymer surface modification by atmospheric pressure plasma jet APPJ. • Jet operation conditions for uniform surface modification were determined. • The APPJ added O atoms to the polymer surface and also enhanced the roughness. • The degree of polymer surface modification by APPJ and DBD were compared. • The APPJ is more efficient in attaching O atoms and produces less polymer fragments. - Abstract: In this work we report the surface modification of different engineering polymers, such as, polyethylene terephthalate (PET), polyethylene (PE) and polypropylene (PP) by an atmospheric pressure plasma jet (APPJ). It was operated with Ar gas using 10 kV, 37 kHz, sine wave as an excitation source. The aim of this study is to determine the optimal treatment conditions and also to compare the polymer surface modification induced by plasma jet with the one obtained by another atmospheric pressure plasma source – the dielectric barrier discharge (DBD). The samples were exposed to the plasma jet effluent using a scanning procedure, which allowed achieving a uniform surface modification. The wettability assessments of all polymers reveal that the treatment leads to reduction of more than 40° in the water contact angle (WCA). Changes in surface composition and chemical bonding were analyzed by x-ray photoelectron spectroscopy (XPS) and Fourier-Transformed Infrared spectroscopy (FTIR) that both detected incorporation of oxygen-related functional groups. Surface morphology of polymer samples was investigated by Atomic Force Microscopy (AFM) and an increase of polymer roughness after the APPJ treatment was found. The plasma-treated polymers exhibited hydrophobic recovery expressed in reduction of the O-content of the surface upon rinsing with water. This process was caused by the dissolution of low molecular weight oxidized materials (LMWOMs) formed on the surface as a result of the plasma exposure.

  17. Decreased Bacterial Attachment and Protein Adsorption to Coatings Produced by Low Enegy Plasma Polymerization

    DEFF Research Database (Denmark)

    Andersen, T.E.; Kingshott, Peter; Benter, M.

    with a surface less prone to the adsorption of biological matter. In the current study two different hydrophilic nanoscale coatings were produced by low energy plasma polymerization [3] and investigated· f()rl()w ... pr()tein adsorption and bacterial attachment properties. Methods were setup to enable...... and Methods: Coatings: Plasma polymerized poly(vinyl pyrrolidone) (PP-PVP), poly(2-methoxyethyl methacrylate) (PPPMEA) or an inorganic oxide (10) coating were applied onto medical grade silicon rubber sheets (Silopren LSR 2050, Momentive Performance Materials Inc.). Plasma polymerization chamber......-coated crystals were then treated with one of the plasma polymerized coatings. Adsorption of fibrinogen, human serum albumin or immunoglobulin G was measured using a QCM-D instrument [5] (model E4, Q-Sense AB, Vastra Frolunda, Sweden) using a solution of 50llg/1 protein in PBS buffer. Results and Discussion: Our...

  18. Fractal Evolving Theory and Growing Model of Olefin Polymerization Process

    Institute of Scientific and Technical Information of China (English)

    霍超; 任晓红; 等

    2003-01-01

    The surface morphology of Ti-Mg supported catalyst and the polyethylene particles are studied using scanning electron microscope(SEM) technology.The results show that either the catalyst's surface or polymer particle's surface is irregular and has fractal characteristics,which can be described by fractal parameter.The more interesting discovery is that the surface fractal dimension values of the polymer particles vary periodically with the polymerization time.We call this phenomenon fractal evolution,which can be divided into the "revolution" stage and the "evolution" stage,And then we present polymerization fractal growing model(PFGM),and successfully describe and /or predict the whole evolving process of the polyethylene particle morphology under the different slurry polymerization(including pre-polymerization) conditions without H2.

  19. Plasma-polymerized hexamethyldisilazane treated by nitrogen plasma immersion ion implantation technique

    Energy Technology Data Exchange (ETDEWEB)

    Honda, R Y; Mota, R P; Batocki, R G S; Santos, D C R; Nicoleti, T; Kostov, K G; Kayama, M E; Algatti, M A [Laboratorio de Plasma, Faculdade de Engenharia, UNESP, Av. Dr Ariberto Pereira da Cunha-333, 12516-410, Guaratingueta, SP (Brazil); Cruz, N C [Laboratorio de Plasmas Tecnologicos, Unidade Diferenciada, UNESP, Av. Tres de Marco-511, 18085-180, Sorocaba, SP (Brazil); Ruggiero, L, E-mail: honda@feg.unesp.b [Faculdade de Ciencias, UNESP, Av. Luis E. Carrijo Coube 14-1, 17033-360, Bauru, SP (Brazil)

    2009-05-01

    This paper describes the effect of nitrogen Plasma Immersion Ion Implantation (PIII) on chemical structure, refraction index and surface hardness of plasma-polymerized hexamethyldisilazane (PPHMDSN) thin films. Firstly, polymeric films were deposited at 13.56 MHz radiofrequency (RF) Plasma Enhanced Chemical Vapour Deposition (PECVD) and then, were treated by nitrogen PIII from 15 to 60 min. Fourier Transformed Infrared (FTIR) spectroscopy was employed to analyse the molecular structure of the samples, and it revealed that vibrations modes at 3350 cm{sup -1}, 2960 cm{sup -1}, 1650 cm{sup -1}, 1250 cm{sup -1} and 1050 cm{sup -1} were altered by nitrogen PIII. Visible-ultraviolet (vis-UV) spectroscopy was used to evaluate film refractive index and the results showed a slight increase from 1.6 to 1.8 following the implantation time. Nanoindentation revealed a surface hardness rise from 0.5 to 2.3 GPa as PIII treatment time increased. These results indicate nitrogen PIII is very promising in improving optical and mechanical properties of PPHMDSN films.

  20. Pulsed Plasma Methods in Materials Processing

    Science.gov (United States)

    Rej, D. J.

    1996-05-01

    Plasmas are routinely used to synthesize advanced materials, because of their ability to produce reactant species that enable a wide variety of chemical reactions. For example, in microelectronics manufacturing, plasmas are used to etch, clean, ash photoresist, implant, deposit, polymerize, and metalize. The use of pulsed power may extend the utility of plasma processing. Pulsed devices such as coaxial plasma guns, cathodic arcs, pseudosparks have been employed to synthesize materials ranging from novel steel alloys and high-temperature superconductors to diamond coatings. In this talk, we will highlight plasma immersion ion implantation and deposition, methods that improve conventional steady-state chemical and physical vapor deposition techniques. Pulsed power enables energetic ion bombardment before plasma deposition to promote better film adhesion through the formation of a graded interface. Ion bombardment during deposition reduces residual stress in the deposited film, thereby enabling formation of thick layers. Also, pulsed plasma sources have advantages over steady-state devices in that they conserve electrical power and can produce high-density, fully-dissociated plasmas. As an example, we will review recent experiments on the formation of adherent diamond-like carbon films deposited onto relatively large batches of automotive components.

  1. Synthesis of PPy-like Nanocrystallines by Oriented Plasma Polymerization at Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    FANG Xin-sheng; GUO Ying; XU Jin-zhou; ZHANG Jing

    2006-01-01

    Polymeric polypyrrole-like (PPy-like) nanocrystallines were fast synthesized through oriented plasma polymerization at atmospheric pressure and room temperature. The effects of discharge power on the nanocrystalline morphology were investigated. Larger power tends to produce longer nanocrystallines. 3 mm long nanowires were produced at the largest power in our experiment. TEM image and the sharp electronic diffraction spots in SAD suggest that the nanoparticles have a single crystal phase. The chemical structure of the nanocrystalline has been studied through FTIR, EDX etc. This novel polymerization method could have great applications in fabricating functional polymeric nanocrystallines.

  2. Surface modification of aramid fiber by plasma induced vapor phase graft polymerization of acrylic acid. I. Influence of plasma conditions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C.X., E-mail: cxwang@mail.dhu.edu.cn [College of Textiles and Clothing, Yancheng Institute of Technology, Jiangsu 224003 (China); School of Textile and Clothing, Nantong University, Jiangsu 226019 (China); Du, M. [College of Textiles and Clothing, Yancheng Institute of Industry Technology, Jiangsu 224000 (China); Lv, J.C.; Zhou, Q.Q. [College of Textiles and Clothing, Yancheng Institute of Technology, Jiangsu 224003 (China); Ren, Y. [School of Textile and Clothing, Nantong University, Jiangsu 226019 (China); Liu, G.L.; Gao, D.W. [College of Textiles and Clothing, Yancheng Institute of Technology, Jiangsu 224003 (China); Jin, L.M. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204 (China)

    2015-09-15

    Highlights: • Aramid fiber surface was modified by PIVPGP of AA to improve wettability, adhesion. • Surface modification effect by PIVPGP of AA increased and then decreased with time. • Surface modification effect increased and then stayed unaltered with output power. • Ar plasma was the most effective in PIVPGP of AA on aramid fiber surface. • In studied range, optimum technology of PIVPGP of AA: Ar plasma, 15 min, 300 W. - Abstract: Plasma induced vapor phase graft polymerization (PIVPGP) method was applied to modify aramid fiber surface. In this study, aramid fibers were pretreated under various plasma conditions such as different treatment times, output powers and working gases to see how these plasma processing parameters influenced the PIVPGP of acrylic acid (AA) on aramid fiber surface and its surface structure and properties. The analysis results of atomic force microscope (AFM) and X-ray photoelectron spectroscope (XPS) showed the increase of surface roughness and the introduction of O=C−OH, which confirmed that the PIVPGP of AA on aramid fiber surface was achieved. The contact angle and interfacial shear strength (IFSS) of the aramid fibers modified by PIVPGP of AA prominently decreased and increased, respectively, indicating the obvious improvements of surface wettability and adhesion between aramid fiber and matrix. The surface modification effects of aramid fiber by PIVPGP of AA firstly increased and then after 15 min slightly decreased with the increasing plasma treatment time, and but firstly increased and then after 300 W nearly remained unchanged with the increasing output power, respectively. Among different working gases, Ar plasma occupied first place, O{sub 2} plasma and N{sub 2} plasma came second and third in the aspect of PIVPGP of AA on aramid fiber surface, respectively. It could be concluded that the PIVPGP of AA on aramid fiber surface could effectively improve surface wettability and adhesion. Plasma conditions had signally

  3. Controlled chemical and morphological surface modifications via pulsed plasma polymerizations: Synthesis of ultrahydrophobic surfaces

    Science.gov (United States)

    Qiu, Haibo

    The RF plasma polymerization of saturated linear and cyclic perfluoroalkane monomers and vinyl acetic acid were studied in this dissertation. Film chemical compositions, deposition rates, surface wettabilities and morphologies were characterized as functions of various plasma processing conditions. Large progressive changes in chemical compositions with sequential variations in plasma duty cycle were demonstrated in polymerization of both perfluoroalkane and vinyl acetic acid monomers. As anticipated, polymer films obtained from the perfluorocarbon monomers exhibited a general trend towards more linear structures with decreasing plasma duty cycles. However, completely unexpectedly, ultrahydrophobic films were obtained from some of these monomers under restricted duty cycle and power input conditions. SEM and XPS characterizations revealed that a rough, fibrous-like surface morphology is responsible for this ultrahydrophobicity, as opposed to unusual chemical compositions. The growth of the fibrous surface is believed to arise from nucleation and hillock-like growth patterns on selectively activated sites of the growing polymer film. Surface mobility of plasma generated reactive species apparently plays an important role in the growth of the fibrous ultrahydrophobic surfaces, as shown by substrate temperature studies. Additionally, the present study revealed a number of interesting new observations of significant differences in the chemical compositions and deposition rates of polymer films obtained from the diverse range of perfluorocarbon monomers employed in this work. The ultrahydrophobic fluorocarbon films discovered in this investigation were evaluated for use in several biomaterial applications. The results obtained show excellent marine antifouling properties for these surfaces, as documented in ocean testing experiments. These surfaces have also been shown to be useful in controlling protein and peptide surface adsorptions, as well as in the inflammatory

  4. Surface Modification of Carbon Nanofibers and Graphene Platelets Mixtures by Plasma Polymerization of Propylene

    Directory of Open Access Journals (Sweden)

    Carlos Andrés Covarrubias-Gordillo

    2017-01-01

    Full Text Available Carbon nanofibers (CNFs, graphene platelets (GPs, and their mixtures were treated by plasma polymerization of propylene. The carbon nanoparticles (CNPs were previously sonicated in order to deagglomerate and increase the surface area. Untreated and plasma treated CNPs were analyzed by dynamic light scattering (DLS, transmission electron microscopy (TEM, Fourier transform infrared spectroscopy (FTIR, Raman spectroscopy, and thermogravimetric analysis (TGA. DLS analysis showed a significant reduction of average particle size, due to the sonication pretreatment. Plasma polymerized propylene was deposited on the CNPs surface; the total amount of polymerized propylene was from 4.68 to 6.58 wt-%. Raman spectroscopy indicates an increase in the sp3 hybridization of the treated samples, which suggest that the polymerized propylene is grafted onto the CNPs.

  5. Enzyme biosensor based on plasma-polymerized film-covered carbon nanotube layer grown directly on a flat substrate.

    Science.gov (United States)

    Muguruma, Hitoshi; Hoshino, Tatsuya; Matsui, Yasunori

    2011-07-01

    We report a novel approach to fabrication of an amperometric biosensor with an enzyme, a plasma-polymerized film (PPF), and carbon nanotubes (CNTs). The CNTs were grown directly on an island-patterned Co/Ti/Cr layer on a glass substrate by microwave plasma enhanced chemical vapor deposition. The as-grown CNTs were subsequently treated by nitrogen plasma, which changed the surface from hydrophobic to hydrophilic in order to obtain an electrochemical contact between the CNTs and enzymes. A glucose oxidase (GOx) enzyme was then adsorbed onto the CNT surface and directly treated with acetonitrile plasma to overcoat the GOx layer with a PPF. This fabrication process provides a robust design of CNT-based enzyme biosensor, because of all processes are dry except the procedure for enzyme immobilization. The main novelty of the present methodology lies in the PPF and/or plasma processes. The optimized glucose biosensor revealed a high sensitivity of 38 μA mM(-1) cm(-2), a broad linear dynamic range of 0.25-19 mM (correlation coefficient of 0.994), selectivity toward an interferent (ascorbic acid), and a fast response time of 7 s. The background current was much smaller in magnitude than the current due to 10 mM glucose response. The low limit of detection was 34 μM (S/N = 3). All results strongly suggest that a plasma-polymerized process can provide a new platform for CNT-based biosensor design.

  6. Cold-atmospheric pressure plasma polymerization of acetylene on wood flour for improved wood plastics composites

    Science.gov (United States)

    Lekobou, William; Pedrow, Patrick; Englund, Karl; Laborie, Marie-Pierre

    2009-10-01

    Plastic composites have become a large class of construction material for exterior applications. One of the main disadvantages of wood plastic composites resides in the weak adhesion between the polar and hydrophilic surface of wood and the non-polar and hydrophobic polyolefin matrix, hindering the dispersion of the flour in the polymer matrix. To improve interfacial compatibility wood flour can be pretreated with environmentally friendly methods such as cold-atmospheric pressure plasma. The objective of this work is therefore to evaluate the potential of plasma polymerization of acetylene on wood flour to improve the compatibility with polyolefins. This presentation will describe the reactor design used to modify wood flour using acetylene plasma polymerization. The optimum conditions for plasma polymerization on wood particles will also be presented. Finally preliminary results on the wood flour surface properties and use in wood plastic composites will be discussed.

  7. Processes for microemulsion polymerization employing novel microemulsion systems

    Science.gov (United States)

    Beckman, Eric J.; Smith, Richard D.; Fulton, John L.

    1990-06-12

    This invention is directed to a microemulsion system comprising a first phase including a low-polarity fluid material which is a gas at standard temperature and pressure, and which has a cloud-point density. It also includes a second phase including a polar fluid, typically water, a monomer, preferably a monomer soluble in the polar fluid, and a microemulsion promoter for facilitating the formation of micelles including the monomer in the system. In the subject process, micelles including the monomer are formed in the first phase. A polymerization initiator is introduced into the micelles in the microemulsion system. The monomer is then polymerized in the micelles, preferably in the core of the micelle, to produce a polymeric material having a relatively high molecular weight.

  8. Micro-fluidic partitioning between polymeric sheets for chemical amplification and processing

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Brian L.

    2017-01-24

    A system for fluid partitioning for chemical amplification or other chemical processing or separations of a sample, comprising a first dispenser of a first polymeric sheet, wherein the first polymeric sheet contains chambers; a second dispenser of a second polymeric sheet wherein the first dispenser and the second dispenser are positioned so that the first polymeric sheet and the second polymeric sheet become parallel; a dispenser of the fluid positioned to dispense the fluid between the first polymeric sheet and the second polymeric sheet; and a seal unit that seals the first polymeric sheet and the second polymeric sheet together thereby sealing the sample between the first polymeric sheet and the second polymeric sheet and partitioning the fluid for chemical amplification or other chemical processing or separations.

  9. Comparative studies of chemically synthesized and RF plasma-polymerized poly(-toluidine)

    Indian Academy of Sciences (India)

    Shama Islam; G B V S Lakshmi; M Zulfequar; M Husain; Azher M Siddiqui

    2015-04-01

    Poly(-toluidine) (POT) polymer was synthesized by chemical method and RF plasma polymerization at a radio frequency (RF) power input of 15 W on ultrasonically cleaned glass and silicon wafer substrates. These samples were characterized by DC conductivity measurements, UV–visible, XRD and FTIR techniques. The DC-conductivity was measured at 410 K, which was found to increase by two orders of magnitude for thin film as compared to pellet samples. It has been observed that the activation energy increases for RF plasma-polymerized POT. Transmission and reflectance spectra were studied for measuring optical constants like absorption coefficient (), extinction coefficient (), optical band gap (g), Urbach energy (e), and refractive index (). From XRD studies, one can infer that the samples grown by both the methods are amorphous in nature. The results indicate that the structures of plasma-polymerized POT are rather different from polymers synthesized by conventional chemical methods, due to a higher degree of cross-linking and branching reactions in plasma polymerization. This makes them suitable for various electroactive devices. A higher and more stable conductivity can be obtained with RF plasma-polymerized POT which is much smoother and more uniform.

  10. The Research on Modeling and Simulation of TFE Polymerization Process

    Directory of Open Access Journals (Sweden)

    Jing Gao Sun

    2014-01-01

    Full Text Available PTFE (polytetrafluoroethylene is the fluorinated straight-chain polymer, made by the polymerization of tetrafluoroethylene monomer; it is used widely because of its excellent performance and can be obtained by the polymerization of body, solutions, suspensions, and emulsions. But only the last two are the main ways. This research paper makes simulation based on Polymer Plus. It uses the emulsion polymerization method at background to carry out a semibatch reactor system. Upon the actual production conditions, simulation process under the steady state conditions is used to analyze the effects of the changes on operating conditions; the corresponding dynamic model is created to analyze the impact of the changes of conditions on the entire system. Moreover, the amount of APS which plays an important part in this reaction is discussed for getting the most suitable amount of initiator. Because of less research work on this job, it is so difficult to find the related data from the literature. Therefore, this research will have a great significance for the process of the tetrafluoroethylene emulsion polymerization in the future.

  11. Decreased material-activation of the complement system using low-energy plasma polymerized poly(vinyl pyrrolidone) coatings

    DEFF Research Database (Denmark)

    Andersen, T.E.; Kolmos, H.J.; Palarasah, Yaseelan

    2011-01-01

    surface. The ppVP surface is furthermore characterized physically and chemically using scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR), which indicates preservation of chemical functionality by the applied plasma process. Overall, the pp......In the current study we investigate the activation of blood complement on medical device silicone rubber and present a plasma polymerized vinyl pyrrolidone (ppVP) coating which strongly decreases surface-activation of the blood complement system. We show that uncoated silicone and polystyrene...

  12. Immobilization and controlled release of drug using plasma polymerized thin film

    Energy Technology Data Exchange (ETDEWEB)

    Myung, Sung-Woon [Department of Dental Materials, School of Dentistry, MRC Center, Chosun University, 309 Pilmun-daero, Dong-gu, Gwangju (Korea, Republic of); Jung, Sang-Chul [Department of Environmental Engineering, Sunchon National University, Sunchon 540-742 (Korea, Republic of); Kim, Byung-Hoon, E-mail: kim5055@chosun.ac.kr [Department of Dental Materials, School of Dentistry, MRC Center, Chosun University, 309 Pilmun-daero, Dong-gu, Gwangju (Korea, Republic of)

    2015-06-01

    In this study, plasma polymerization of acrylic acid was employed to immobilize drug and control its release. Doxorubicin (DOX) was immobilized covalently on the glass surface deposited with plasma polymerized acrylic acid (PPAAc) thin film containing the carboxylic group. At first, the PPAAc thin film was coated on a glass surface at a pressure of 1.33 Pa and radio frequency (RF) discharge power of 20 W for 10 min. DOX was immobilized on the PPAAc deposition in a two environment of phosphate buffer saline (PBS) and dimethyl sulfoxide (DMSO) solutions. The DOX immobilized surface was characterized by scanning electron microscope, atomic force microscope and attenuated total reflection Fourier transform infrared spectroscopy. The DOX molecules were more immobilized in PBS than DMSO solution. The different immobilization and release profiles of DOX result from the solubility of hydrophobic DOX in aqueous and organic solutions. Second, in order to control the release of the drug, PPAAc thin film was covered over DOX dispersed layer. Different thicknesses and cross-linked PPAAc thin films by adjusting deposition time and RF discharge power were covered on the DOX layer dispersed. PPAAc thin film coated DOX layer reduced the release rate of DOX. The thickness control of plasma deposition allows controlling the release rate of drug. - Highlights: • Doxorubicin was immobilized on the surface of plasma polymerized acrylic acid thin film. • Release profile of doxorubicin was affected by aqueous and organic solutions. • Plasma polymerized acrylic acid thin film can be used to achieve controlled release.

  13. Surface modification of biomaterials by pulsed laser ablation deposition and plasma/gamma polymerization

    Science.gov (United States)

    Rau, Kaustubh R.

    Surface modification of stainless-steel was carried out by two different methods: pulsed laser ablation deposition (PLAD) and a combined plasma/gamma process. A potential application was the surface modification of endovascular stents, to enhance biocompatibility. The pulsed laser ablation deposition process, had not been previously reported for modifying stents and represented a unique and potentially important method for surface modification of biomaterials. Polydimethylsiloxane (PDMS) elatomer was studied using the PLAD technique. Cross- linked PDMS was deemed important because of its general use for biomedical implants and devices as well as in other fields. Furthermore, PDMS deposition using PLAD had not been previously studied and any information gained on its ablation characteristics could be important scientifically and technologically. The studies reported here showed that the deposited silicone film properties had a dependence on the laser energy density incident on the target. Smooth, hydrophobic, silicone-like films were deposited at low energy densities (100-150 mJ/cm2). At high energy densities (>200 mJ/cm2), the films had an higher oxygen content than PDMS, were hydrophilic and tended to show a more particulate morphology. It was also determined that (1)the deposited films were stable and extremely adherent to the substrate, (2)silicone deposition exhibited an `incubation effect' which led to the film properties changing with laser pulse number and (3)films deposited under high vacuum were similar to films deposited at low vacuum levels. The mechanical properties of the PLAD films were determined by nanomechanical measurements which are based on the Atomic Force Microscope (AFM). From these measurements, it was possible to determine the modulus of the films and also study their scratch resistance. Such measurement techniques represent a significant advance over current state-of-the-art thin film characterization methods. An empirical model for

  14. Plasma Processing of Materials

    Science.gov (United States)

    1985-02-22

    used in France. In this case, three ’ movable electrodes arranged about the central axis with a coaxial sheath gas are employed. Initially the...Demiocratic Republic plasma furnace. chrome -magnesite; the bottom section is lined with rammed chrome -magnesite refractory. Due to the high heat loads... sheath injector design, cathode tip shape, and degree of water cooling are important parameters in providing a stable, uncontaminating, long-lifetime

  15. TFE-PLASMA POLYMERIZED DERMAL SHEEP COLLAGEN FOR THE REPAIR OF ABDOMINAL-WALL DEFECTS

    NARCIS (Netherlands)

    VANDERLAAN, JS; LOPEZ, GP; VANWACHEM, PB; NIEUWENHUIS, P; RATNER, BD; BLEICHRODT, RP; SCHAKENRAAD, JM

    1991-01-01

    The aim of this study was to design and evaluate a degradable biomaterial for the repair of abdominal wall defects. Hexamethylenediisocyanate-tanned dermal sheep collagen (HDSC) was plasma-polymerized with tetrafluoroethylene (TFE) which resulted in a hydrophobic surface on the visceral side (TFE-HD

  16. Surface modification by allylamine plasma polymerization promotes osteogenic differentiation of human adipose-derived stem cells.

    Science.gov (United States)

    Liu, Xujie; Feng, Qingling; Bachhuka, Akash; Vasilev, Krasimir

    2014-06-25

    Tuning the material properties in order to control the cellular behavior is an important issue in tissue engineering. It is now well-established that the surface chemistry can affect cell adhesion, proliferation, and differentiation. In this study, plasma polymerization, which is an appealing method for surface modification, was employed to generate surfaces with different chemical compositions. Allylamine (AAm), acrylic acid (AAc), 1,7-octadiene (OD), and ethanol (ET) were used as precursors for plasma polymerization in order to generate thin films rich in amine (-NH2), carboxyl (-COOH), methyl (-CH3), and hydroxyl (-OH) functional groups, respectively. The surface chemistry was characterized by X-ray photoelectron spectroscopy (XPS), the wettability was determined by measuring the water contact angles (WCA) and the surface topography was imaged by atomic force microscopy (AFM). The effects of surface chemical compositions on the behavior of human adipose-derive stem cells (hASCs) were evaluated in vitro: Cell Count Kit-8 (CCK-8) analysis for cell proliferation, F-actin staining for cell morphology, alkaline phosphatase (ALP) activity analysis, and Alizarin Red S staining for osteogenic differentiation. The results show that AAm-based plasma-polymerized coatings can promote the attachment, spreading, and, in turn, proliferation of hASCs, as well as promote the osteogenic differentiation of hASCs, suggesting that plasma polymerization is an appealing method for the surface modification of scaffolds used in bone tissue engineering.

  17. Surface modification of poly(ethylene terephthalate) by plasma polymerization of poly(ethylene glycol).

    Science.gov (United States)

    Sakthi Kumar, D; Fujioka, Masayori; Asano, Kentaro; Shoji, Atsumu; Jayakrishnan, Athipettah; Yoshida, Yasuhiko

    2007-09-01

    Poly(ethylene glycol) (PEG) was 'polymerized' onto poly(ethylene terephthalate) (PET) surface by radio frequency (RF) plasma polymerization of PEG (average molecular weight 200 Da) at a monomer vapour partial pressure of 10 Pa. Thin films strongly adherent onto PET could be produced by this method. The modified surface was characterized by infra red (IR) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), cross-cut test, contact angle measurements and static platelet adhesion studies. The modified surface, believed to be extensively cross-linked, however showed all the chemical characteristics of PEG. The surface was found to be highly hydrophilic as evidenced by an interfacial free energy of about 0.7 dynes/cm. AFM studies showed that the surface of the modified PET became smooth by the plasma polymerized deposition. Static platelet adhesion studies using platelet rich plasma (PRP) showed considerably reduced adhesion of platelets onto the modified surface by SEM. Plasma 'polymerization' of a polymer such as PEG onto substrates may be a novel and interesting strategy to prepare PEG-like surfaces on a variety of substrates since the technique allows the formation of thin, pin-hole free, strongly adherent films on a variety of substrates.

  18. Studies on the runaway reaction of ABS polymerization process.

    Science.gov (United States)

    Hu, Kwan-Hua; Kao, Chen-Shan; Duh, Yih-Shing

    2008-11-15

    Taiwan has the largest acrylonitrile-butadiene-styrene (ABS) copolymer production in the world. Preventing on unexpected exothermic reactions and related emergency relief hazard is essential in the safety control of ABS emulsion polymerization. A VSP2 (Vent Sizing Package 2) apparatus is capable of studying both normal and abnormal conditions (e.g., cooling failure, mischarge, etc.) of industrial process. In this study, the scenarios were verified from the following abnormal conditions: loss of cooling, double charge of initiator, overcharge of monomer, without charge of solvent, and external fire. An external fire with constant heating will promote higher self-heat rate and this is recommended as the worst case scenario of emulsion polymerization on butadiene. Cooling failure coupled with bulk system of reactant was determined to be the credible worst case in ABS emulsion polymerization. Finally, the emergency vent sizing based on thermokinetics from VSP associated with DIERS methodology were used for evaluating the vent sizing and compared to that of the industrial plants.

  19. Polyurethane coating with thin polymer films produced by plasma polymerization of diglyme

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, M A; Ramos, A S; Manfredini, M I; Alves, H A; Ramos, E C T [UNIVAP, Sao Jose dos Campos, SP (Brazil); Honda, R Y; Kostov, K G; Lucena, E F; Mota, R P; Algatti, M A; Kayama, M E, E-mail: rmota@feg.unesp.b [FEG-DFQ-UNESP, Av. Ariberto Pereira da Cunha 333, 12516-410 - Guaratingueta, SP (Brazil)

    2009-05-01

    Aqueous-based polyurethane dispersions have been widely utilized as lubricants in textile, shoes, automotive, biomaterial and many other industries because they are less aggressive to surrounding environment. In this work thin films with different thickness were deposited on biocompatible polyurethane by plasma polymerization process using diethylene glycol dimethyl ether (Diglyme) as monomer. Molecular structure of the films was analyzed by Fourier Transform Infrared spectroscopy. The spectra exhibited absorption bands of O-H (3500-3200cm{sup -1}), C-H (3000-2900cm{sup -1}), C=O (1730-1650cm{sup -1}), C-O and C-O-C bonds at 1200-1600cm{sup -1}. The samples wettability was evaluated by measurements of contact angle using different liquids such as water, glycerol, poly-ethane and CMC. The polyurethane surface showed hydrophilic behavior after diglyme plasma-deposition with contact angle dropping from 85 deg. to 22 deg. Scanning Electron Microscopy revealed that diglyme films covered uniformly the polyurethane surfaces ensuring to it a biocompatible characteristic.

  20. Characterization and properties of plasma polymerized 2-vinylpyridine

    Energy Technology Data Exchange (ETDEWEB)

    Bieg, K.W.; Ottesen, D.K.; Brower, K.L.

    1979-11-01

    The chemical structure, aging, thermal, and adhesive behavior of plasma-deposited 2-vinylpyridine has been investigated. The molecular structure of the plasma polymer is significantly different from the conventional, linear polymer and is strongly dependent on plasma reactor variables. Additional cyano, methyl, and olefinic groups were identified in the plasma polymer, and aromaticity retention was reduced at the more severe (low pressure, high rf power) reactor conditions studied. Post-deposition oxidation occurred, which followed approximately first order kinetics initially (..delta..E approx. 11.6 Kcal/mole, with approx. 25% conversion of aromatic rings to an aromatic ketone in 4.5 months at 23/sup 0/C). Oxidation was significantly reduced in vacuum, inert gas, and hydrogen atmospheres. Thermal weight loss began at relatively low temperatures and appeared to accompany an exothermic, irreversible cross-linking reaction which began at about 100/sup 0/C. Principle low temperature decomposition products were low molecular weight gases (primarily, CO/sub 2/) and 2-methylpyridine. A quantitative tensile-pull adhesion test was developed. Using this technique, the plasma polymer-aluminum cohesive bond strength was found to be 480 psi and was degraded at high humidity levels.

  1. Combinatorial plasma polymerization approach to produce thin films for testing cell proliferation.

    Science.gov (United States)

    Antonini, V; Torrengo, S; Marocchi, L; Minati, L; Dalla Serra, M; Bao, G; Speranza, G

    2014-01-01

    Plasma enhanced physical vapor depositions are extensively used to fabricate substrates for cell culture applications. One peculiarity of the plasma processes is the possibility to deposit thin films with reproducible chemical and physical properties. In the present work, a combinatorial plasma polymerization process was used to deposit thin carbon based films to promote cell adhesion, in the interest of testing cell proliferation as a function of the substrate chemical properties. Peculiarity of the combinatorial approach is the possibility to produce in just one deposition experiment, a set of surfaces of varying chemical moieties by changing the precursor composition. A full characterization of the chemical, physical and thermodynamic properties was performed for each set of the synthesized surfaces. X-ray photoelectron spectroscopy was used to measure the concentration of carboxyl, hydroxyl and amine functional groups on the substrate surfaces. A perfect linear trend between polar groups' density and precursors' concentration was found. Further analyses reveled that also contact angles and the correspondent surface energies of all deposited thin films are linearly dependent on the precursor concentration. To test the influence of the surface composition on the cell adhesion and proliferation, two cancer cell lines were utilized. The cell viability was assessed after 24 h and 48 h of cell culture. Experiments show that we are able to control the cell adhesion and proliferation by properly changing the thin film deposition conditions i.e. the concentration and the kind of chemical moiety on the substrate surface. The results also highlight that physical and chemical factors of biomaterial surface, including surface hydrophobicity and free energy, chemical composition, and topography, can altered cell attachment.

  2. Surface modification of polymeric materials by plasma immersion ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Ricky K.Y. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Cheung, I.T.L. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Mei, Y.F. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Shek, C.H. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Siu, G.G. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)]. E-mail: paul.chu@cityu.edu.hk; Yang, W.M. [School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Leng, Y.X. [School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Huang, Y.X. [State Key Laboratory of Welding Production Technology, Harbin Institute of Technology, Harbin (China); Tian, X.B. [State Key Laboratory of Welding Production Technology, Harbin Institute of technology, Harbin (China); Yang, S.Q. [State Key Laboratory of Welding Production Technology, Harbin Institute of Technology, Harbin (China)

    2005-08-01

    Polymer surfaces typically have low surface tension and high chemical inertness and so they usually have poor wetting and adhesion properties. The surface properties can be altered by modifying the molecular structure using plasma immersion ion implantation (PIII). In this work, Nylon-6 was treated using oxygen/nitrogen PIII. The observed improvement in the wettability is due to the oxygenated and nitrogen (amine) functional groups created on the polymer surface by the plasma treatment. X-ray photoelectron spectroscopy (XPS) results show that nitrogen and oxygen plasma implantation result in C-C bond breaking to form the imine and amine groups as well as alcohol and/or carbonyl groups on the surface. The water contact angle results reveal that the surface wetting properties depend on the functional groups, which can be adjusted by the ratio of oxygen-nitrogen mixtures.

  3. Robust Plasma Polymerized-Titania/Silica Janus Microparticles

    Science.gov (United States)

    2010-04-29

    fluorescent, half- metal -decorated, and half-shelled structures were all demonstrated here as particular examples. Introduction Janus particles result from...for the selective reduction of metal nanoparticles, site-selective grafting, potential biological activity, and generating distinct optical response...of coatings providing for biological activities and biomineralization including Figure 4. AFM topography (left) and phase (right) of plasma coatings

  4. Preparation and properties of plasma-polymerized thiophene (PPT) conducting films

    Energy Technology Data Exchange (ETDEWEB)

    Sadhir, R.K. (Westinghouse Science and Tech. Center, Pittsburgh, PA (United States)); Schoch, K.F. Jr. (Westinghouse Science and Tech. Center, Pittsburgh, PA (United States))

    1993-01-15

    This paper presents, for the first time, conducting films of polythiophene prepared by plasma-polymerization. In this technique, ionized argon is the initiating species for the polymerization of thiophene in a region away from the high RF flux-density. These films displayed a conductivity of 1.8 x 10[sup -4] S cm[sup -1] after doping with iodine. The surface morphology of the films deposited away from the high RF flux-density region showed topology similar to the films prepared by electrochemical methods. The films deposited near the high RF flux-density region showed a platelet structure. (orig.)

  5. A secondary fuel removal process: plasma processing

    Energy Technology Data Exchange (ETDEWEB)

    Min, J. Y.; Kim, Y. S. [Hanyang Univ., Seoul (Korea, Republic of); Bae, K. K.; Yang, M. S. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1997-07-01

    Plasma etching process of UO{sub 2} by using fluorine containing gas plasma is studied as a secondary fuel removal process for DUPIC (Direct Use of PWR spent fuel Into Candu) process which is taken into consideration for potential future fuel cycle in Korea. CF{sub 4}/O{sub 2} gas mixture is chosen for reactant gas and the etching rates of UO{sub 2} by the gas plasma are investigated as functions of CF{sub 4}/O{sub 2} ratio, plasma power, substrate temperature, and plasma gas pressure. It is found that the optimum CF{sub 4}/O{sub 2} ratio is around 4:1 at all temperatures up to 400 deg C and the etching rate increases with increasing r.f. power and substrate temperature. Under 150W r.f. power the etching rate reaches 1100 monolayers/min at 400 deg C, which is equivalent to about 0.5mm/min. (author).

  6. Application of plasma-polymerized films for isoelectric focusing of proteins in a capillary electrophoresis chip.

    Science.gov (United States)

    Tsai, Shuo-Wen; Loughran, Michael; Hiratsuka, Atsunori; Yano, Kazuyoshi; Karube, Isao

    2003-03-01

    The first use of plasma polymerization technique to modify the surface of a glass chip for capillary isoelectric focusing (cIEF) of different proteins is reported. The electrophoresis separation channel was machined in Tempax glass chips with length 70 mm, 300 microm width and 100 microm depth. Acetonitrile and hexamethyldisiloxane monomers were used for plasma polymerization. In each case 100 nm plasma polymer films were coated onto the chip surface to reduce protein wall adsorption and minimize the electroosmotic flow. Applied voltages of 1000 V, 2000 V and 3000 V were used to separate mixtures of cytochrome c (pI 9.6), hemoglobin (pI 7.0) and phycocyanin (pI 4.65). Reproducible isoelectric focusing of each pI marker protein was observed in different coated capillaries at increasing concentration 2.22-5 microg microL(-1). Modification of the glass capillary with hydrophobic HMDS plasma polymerized films enabled rapid cIEF within 3 min. The separation efficiency of cytochrome c and phycocyanin in both acrylamide and HMDS coated capillaries corresponded to a plate number of 19600 which compares favourably with capillary electrophoresis of neurotransmitters with amperometric detection.

  7. High-Voltage Insulation Organic-Inorganic Nanocomposites by Plasma Polymerization

    Directory of Open Access Journals (Sweden)

    Wei Yan

    2014-01-01

    Full Text Available In organic-inorganic nanocomposites, interfacial regions are primarily influenced by the dispersion uniformity of nanoparticles and the strength of interfacial bonds between the nanoparticles and the polymer matrix. The insulating performance of organic-inorganic dielectric nanocomposites is highly influenced by the characteristics of interfacial regions. In this study, we prepare polyethylene oxide (PEO-like functional layers on silica nanoparticles through plasma polymerization. Epoxy resin/silica nanocomposites are subsequently synthesized with these plasma-polymerized nanoparticles. It is found that plasma at a low power (i.e., 10 W can significantly increase the concentration of C–O bonds on the surface of silica nanoparticles. This plasma polymerized thin layer can not only improve the dispersion uniformity by increasing the hydrophilicity of the nanoparticles, but also provide anchoring sites to enable the formation of covalent bonds between the organic and inorganic phases. Furthermore, electrical tests reveal improved electrical treeing resistance and decreased dielectric constant of the synthesized nanocomposites, while the dielectric loss of the nanocomposites remains unchanged as compared to the pure epoxy resin.

  8. Enhancement of Fluorescence-Based Sandwich Immunoassay Using Multilayered Microplates Modified with Plasma-Polymerized Films

    Directory of Open Access Journals (Sweden)

    Kazuyoshi Yano

    2016-12-01

    Full Text Available A functional modification of the surface of a 96-well microplate coupled with a thin layer deposition technique is demonstrated for enhanced fluorescence-based sandwich immunoassays. The plasma polymerization technique enabling the deposition of organic thin films was employed for the modification of the well surface of a microplate. A silver layer and a plasma-polymerized film were consecutively deposited on the microplate as a metal mirror and the optical interference layer, respectively. When Cy3-labeled antibody was applied to the wells of the resulting multilayered microplate without any immobilization step, greatly enhanced fluorescence was observed compared with that obtained with the unmodified one. The same effect could be also exhibited for an immunoassay targeting antigen directly adsorbed on the multilayered microplate. Furthermore, a sandwich immunoassay for the detection of interleukin 2 (IL-2 was performed with the multilayered microplates, resulting in specific and 88-fold–enhanced fluorescence detection.

  9. Plasma detachment with molecular processes in divertor plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Ohno, N.; Ezumi, N.; Nishijima, D.; Takamura, S. [Dept. of Energy Engineering and Science, Graduate School of Engineering, Nagoya Univ., Nagoya, Aichi (Japan); Krasheninnikov, S.I.; Pigarov, A.Yu. [MIT Plasma Science and Fusion Center, Cambridge, MA (United States)

    2000-01-01

    Molecular processes in detached recombining plasmas are briefly reviewed. Several reactions with vibrationally excited hydrogen molecule related to recombination processes are described. Experimental evidence of molecular activated recombination observed in a linear divertor plasma simulator is also shown. (author)

  10. Hydrophobic coating of solid materials by plasma-polymerized thin film using tetrafluoroethylene

    Science.gov (United States)

    Hozumi, K.; Kitamura, K.; Kitade, T.

    1980-01-01

    Glass slides were coated with plasma-polymerized tetrafluoroethylene films of different thickness using the glow discharge technique in a tube-shaped chamber, and the plasma conditions, film growth rates, light permeability of the polymer films, and particle bond strength in the polymer films were studied. Ashed sections of mouse organs and ashed bacillus spores were also coated to give them hydrophobic treatment without damaging their shapes or appearance. The hydrophobic coating of the specimens was successful, and the fine ash patterns were strongly fixed onto the glass slides, making permanent preparations.

  11. Plasma micro-nanotextured polymeric micromixer for DNA purification with high efficiency and dynamic range.

    Science.gov (United States)

    Kastania, Athina S; Tsougeni, Katerina; Papadakis, George; Gizeli, Electra; Kokkoris, George; Tserepi, Angeliki; Gogolides, Evangelos

    2016-10-26

    We present a polymeric microfluidic chip capable of purifying DNA through solid phase extraction. It is designed to be used as a module of an integrated Lab-on-chip platform for pathogen detection, but it can also be used as a stand-alone device. The microfluidic channels are oxygen plasma micro-nanotextured, i.e. randomly roughened in the micro-nano scale, a process creating high surface area as well as high density of carboxyl groups (COOH). The COOH groups together with a buffer that contains polyethylene glycol (PEG), NaCl and ethanol are able to bind DNA on the microchannel surface. The chip design incorporates a mixer so that sample and buffer can be efficiently mixed on chip under continuous flow. DNA is subsequently eluted in water. The chip is able to isolate DNA with high recovery efficiency (96± 11%) in an extremely large dynamic range of prepurified Salmonella DNA as well as from Salmonella cell lysates that correspond to a range of 5 to 1.9 × 10(8) cells (0.263 fg to 2 × 500 ng). The chip was evaluated via absorbance measurements, polymerase chain reaction (PCR), and gel electrophoresis.

  12. Ground-Based Tests of Spacecraft Polymeric Materials under OXY-GEN Plasma-Beam

    Science.gov (United States)

    Chernik, Vladimir; Novikov, Lev; Gaidar, Anna

    2016-07-01

    Spacecraft LEO mission is accompanied by destruction of polymeric material surface under influence of atomic oxygen flow. Sources of molecular, plasma and ion beams are used for the accelerated ground-based tests of spacecraft materials. In the work application of oxygen plasma accelerator of a duoplasmatron type is described. Plasma particles have been accelerated up to average speed of 13-16 km/s. Influence of such beam on materials leads to more intensive destruction of polymers than in LEO. This fact allows to execute tests in the accelerated time scale by a method of an effective fluence. Special measures were given to decrease a concentration of both gaseous and electrode material impurities in the oxygen beam. In the work the results of simulative tests of spacecraft materials and experiments on LEO are considered. Comparison of plasma beam simulation with LEO data has shown conformity for structures of a number of polymeric materials. The relative erosion yields (normalized with respect to polyimide) of the tested materials are shown practically equal to those in LEO. The obtained results give grounds for using the plasma-generation mode with ion energies of 20-30 eV to accelerated testing of spacecraft materials for long -term LEO missions.

  13. Stable modification of PDMS surface properties by plasma polymerization: application to the formation of double emulsions in microfluidic systems.

    Science.gov (United States)

    Barbier, Valessa; Tatoulian, Michaël; Li, Hong; Arefi-Khonsari, Farzaneh; Ajdari, Armand; Tabeling, Patrick

    2006-06-06

    We describe a method based on plasma polymerization for the modification and control of the surface properties of poly(dimethylsiloxane) (PDMS) surfaces. By depositing plasma polymerized acrylic acid coatings on PDMS, we succeeded to fabricate stable (several days) hydrophilic and patterned hydrophobic/hydrophilic surfaces. We used this approach to generate direct and (for the first time in this material) double emulsions in PDMS microchannels.

  14. Polymerization and processing of organic polymers in a magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Douglas, E.P. [Los Alamos National Laboratory, NM (United States)

    1995-05-01

    The use of magnetic fields to affect the structure and properties of polymeric materials remains an area of great promise. Liquid crystalline polymers have been actively studied over the past 20 years for use in high performance structural applications. In particular, highly oriented fibers can exhibit remarkable increases in strength to weight performance compared to conventional materials. For example, the fibers marketed by DuPont under the tradename Kevlar are 20 times stronger than steel on an equivalent weight basis. However, larger bulk parts do not exhibit the same increases in strength due to a lack of orientation of the polymer molecules. Magnetic field processing of polymers remains an attractive solution to this problem.

  15. Plasma diagnostics in plasma processing for nanotechnology and nanolevel chemistry

    Directory of Open Access Journals (Sweden)

    Hiroshi Akatsuka

    2004-01-01

    Full Text Available The author reviews the role of various plasma diagnostics in plasma processing for nanotechnology, and points out some essential methods of spectroscopic methods to diagnose plasmas for nanoprocessing. Two experimental examples are discussed between the characteristics of nanomaterials and plasma parameters. One is measurement of rotation temperature in processing of carbon nanotube. The other is that of vibrational temperature in surface nitriding of titanium by nitrogen plasma processing. We summarize what to measure and how to measure them from the technical viewpoint of plasma diagnostics.

  16. Impact of low-pressure glow-discharge-pulsed plasma polymerization on properties of polyaniline thin films

    Science.gov (United States)

    Jatratkar, Aviraj A.; Yadav, Jyotiprakash B.; Deshmukh, R. R.; Barshilia, Harish C.; Puri, Vijaya; Puri, R. K.

    2016-12-01

    This study reports on polyaniline thin films deposited on a glass substrate using a low-pressure glow-discharge-pulsed plasma polymerization method. The polyaniline thin film obtained by pulsed plasma polymerization has been successfully demonstrated as an optical waveguide with a transmission loss of 3.93 dB cm-1, and has the potential to be employed in integrated optics. An attempt has been made to investigate the effect of plasma OFF-time on the structural, optical as well as surface properties of polyaniline thin film. The plasma ON-time has been kept constant and the plasma OFF-time has been varied throughout the work. The plasma OFF-time strongly influenced the properties of the polyaniline thin film, and a nanostructured and compact surface was revealed in the morphological studies. The plasma OFF-time was found to enhance film thickness, roughness, refractive index and optical transmission loss, whereas it reduced the optical band gap of the polyaniline thin films. Retention in the aromatic structure was confirmed by FTIR results. Optical studies revealed a π-π* electronic transition at about 317 nm as well as the formation of a branched structure. As compared with continuous wave plasma, pulsed plasma polymerization shows better properties. Pulsed plasma polymerization reduced the roughness of the film from 1.2 nm to 0.42 nm and the optical transmission loss from 6.56 dB cm-1 to 3.39 dB cm-1.

  17. Biodegradable and radically polymerized elastomers with enhanced processing capabilities.

    Science.gov (United States)

    Ifkovits, Jamie L; Padera, Robert F; Burdick, Jason A

    2008-09-01

    The development of biodegradable materials with elastomeric properties is beneficial for a variety of applications, including for use in the engineering of soft tissues. Although others have developed biodegradable elastomers, they are restricted by their processing at high temperatures and under vacuum, which limits their fabrication into complex scaffolds. To overcome this, we have modified precursors to a tough biodegradable elastomer, poly(glycerol sebacate) (PGS) with acrylates to impart control over the crosslinking process and allow for more processing options. The acrylated-PGS (Acr-PGS) macromers are capable of crosslinking through free radical initiation mechanisms (e.g., redox and photo-initiated polymerizations). Alterations in the molecular weight and % acrylation of the Acr-PGS led to changes in formed network mechanical properties. In general, Young's modulus increased with % acrylation and the % strain at break increased with molecular weight when the % acrylation was held constant. Based on the mechanical properties, one macromer was further investigated for in vitro and in vivo degradation and biocompatibility. A mild to moderate inflammatory response typical of implantable biodegradable polymers was observed, even when formed as an injectable system with redox initiation. Moreover, fibrous scaffolds of Acr-PGS and a carrier polymer, poly(ethylene oxide), were prepared via an electrospinning and photopolymerization technique and the fiber morphology was dependent on the ratio of these components. This system provides biodegradable polymers with tunable properties and enhanced processing capabilities towards the advancement of approaches in engineering soft tissues.

  18. Advanced plasma diagnostics for plasma processing

    Science.gov (United States)

    Malyshev, Mikhail Victorovich

    1999-10-01

    A new, non-intrusive, non-perturbing diagnostic method was developed that can be broadly applied to low pressure, weakly ionized plasmas and glow discharges-trace rare gases optical emission spectroscopy (TRG-OES). The method is based on a comparison of intensities of atomic emission from trace amounts of inert gases (He, Ne, Ar, Kr, and Xe) that are added to the discharge to intensities calculated from the theoretical model. The model assumes a Maxwellian electron energy distribution function (EEDF), computes the population of emitting levels both from the ground state and the metastable states of rare gases, and from the best fit between theory and experiment determines electron temperature (Te). Subject to conditions, TRG-OES can also yield electron density or its upper or lower limit. From the comparison of the emission from levels excited predominantly by high energy electrons to that excited by low energy electrons, information about the EEDF can be obtained. The use of TRG-OES also allows a traditionally qualitative actinometry technique (determination of concentration of radical species in plasma through optical emission) to become a precise quantitative method by including Te and rare gases metastables effects. A combination of TRG-OES, advanced actinometry, and Langmuir probe measurements was applied to several different plasma reactors and regimes of operation. Te measurements and experiments to correct excitation cross section were conducted in a laboratory helical resonator. Two chamber configuration of a commercial (Lam Research) metal etcher were studied to determine the effects of plasma parameters on plasma-induced damage. Two different methods (RF inductive coupling and ultra-high frequency coupling) for generating a plasma in a prototype reactor were also studied. Pulsed plasmas, a potential candidate to eliminate the plasma-induced damage to microelectronics devices that occurs in manufacturing due to differential charging of the wafer, have

  19. Modelling the Load Torques of Electric Drive for Polymerization Process

    Directory of Open Access Journals (Sweden)

    Andrzej Popenda

    2007-01-01

    Full Text Available The problems of mathematical modelling the load torques on shaft of driving motor designed for applications in polymerization reactors are presented in the paper. The real load of polymerization drive is determined as a function of angular velocity. Mentioned function results from friction in roll-formed slide bearing as well as from friction of ethylene molecules with mixer arms in polymerization reactor chamber. Application of mathematical formulas concerning the centrifugal ventilator is proposed to describe the mixer in reactor chamber. The analytical formulas describing the real loads of polymerization drive are applied in mathematical modelling the power unit of polymerization reactor with specially designed induction motor. The numerical analysis of transient states was made on the basis of formulated mathematical model. Examples of transient responses and trajectories resulting from analysis are presented in the paper.

  20. Wetting, Solubility and Chemical Characteristics of Plasma-Polymerized 1-Isopropyl-4-Methyl-1,4-Cyclohexadiene Thin Films

    Directory of Open Access Journals (Sweden)

    Jakaria Ahmad

    2014-07-01

    Full Text Available Investigations on the wetting, solubility and chemical composition of plasma polymer thin films provide an insight into the feasibility of implementing these polymeric materials in organic electronics, particularly where wet solution processing is involved. In this study, thin films were prepared from 1-isopropyl-4-methyl-1,4-cyclohexadiene (γ-Terpinene using radio frequency (RF plasma polymerization. FTIR showed the polymers to be structurally dissimilar to the original monomer and highly cross-linked, where the loss of original functional groups and the degree of cross-linking increased with deposition power. The polymer surfaces were hydrocarbon-rich, with oxygen present in the form of O–H and C=O functional groups. The oxygen content decreased with deposition power, with films becoming more hydrophobic and, thus, less wettable. The advancing and receding contact angles were investigated, and the water advancing contact angle was found to increase from 63.14° to 73.53° for thin films prepared with an RF power of 10 W to 75 W. The wetting envelopes for the surfaces were constructed to enable the prediction of the surfaces’ wettability for other solvents. The effect of roughness on the wetting behaviour of the films was insignificant. The polymers were determined to resist solubilization in solvents commonly used in the deposition of organic semiconducting layers, including chloroform and chlorobenzene, with higher stability observed in films fabricated at higher RF power.

  1. A three-dimensional finite element model of the polymerization process in dental restorations.

    NARCIS (Netherlands)

    Barink, M.; Mark, P.C. van der; Fennis, W.M.M.; Kuys, R.H.; Kreulen, C.M.; Verdonschot, N.J.J.

    2003-01-01

    Restoration of dental restorations with resin composite is hampered by shrinkage of the material during the polymerization process. In this study, we simulated the polymerization process in a detailed three-dimensional finite element model of a human upper premolar with a cusp-replacing restoration.

  2. Investigation of the Effect of Plasma Polymerized Siloxane Coating for Enzyme Immobilization and Microfluidic Device Conception

    Directory of Open Access Journals (Sweden)

    Kalim Belhacene

    2016-12-01

    Full Text Available This paper describes the impact of a physical immobilization methodology, using plasma polymerized 1,1,3,3, tetramethyldisiloxane, on the catalytic performance of β-galactosidase from Aspergillus oryzae in a microfluidic device. The β-galactosidase was immobilized by a polymer coating grown by Plasma Enhanced Chemical Vapor Deposition (PEVCD. Combined with a microchannel patterned in the silicone, a microreactor was obtained with which the diffusion through the plasma polymerized layer and the hydrolysis of a synthetic substrate, the resorufin-β-d-galactopyranoside, were studied. A study of the efficiency of the immobilization procedure was investigated after several uses and kinetic parameters of immobilized β-galactosidase were calculated and compared with those of soluble enzyme. Simulation and a modelling approach were also initiated to understand phenomena that influenced enzyme behavior in the physical immobilization method. Thus, the catalytic performances of immobilized enzymes were directly influenced by immobilization conditions and particularly by the diffusion behavior and availability of substrate molecules in the enzyme microenvironment.

  3. The use of DBD plasma treatment and polymerization for the enhancement of biomedical UHMWPE

    Energy Technology Data Exchange (ETDEWEB)

    Cools, Pieter, E-mail: Pieter.cools@ugent.be; Van Vrekhem, Stijn; De Geyter, Nathalie; Morent, Rino

    2014-12-01

    Surface modification of polymers for biomedical applications is a thoroughly studied area. The goal of this paper is to show the use of atmospheric pressure plasma technology for the treatment of polyethylene shoulder implants. Atmospheric pressure plasma polymerization of methyl methacrylate will be performed on PE samples to increase the adhesion between the polymer and a PMMA bone cement. For the plasma polymerization, a dielectric barrier discharge is used, operating in a helium atmosphere at an ambient pressure. Parameters such as treatment time, monomer gas flow and discharge power are varied one at a time. Chemical and physical changes at the sample surface are studied making use of X-ray photoelectron spectroscopy and atomic force microscopy measurements. Coating thicknesses are determined by making use of optical reflectance spectroscopy. After characterization, the coated samples are incubated into a phosphate buffered saline solution for a minimum of one week at 37 °C, testing the coating stability when exposed to implant conditions. The results show that PMMA coatings can be deposited with a high degree of control in terms of chemical composition and layer thickness. - Highlights: • Medium pressure DBD successfully activates UHMWPE substrates. • Deposition of PMMA like film via atmospheric pressure DBD on activated UHMWPE • Fast deposition rate is confirmed via optical reflectance spectroscopy. • Relative stable coating found after tests in PBS solution and analysed via FT-IR.

  4. Antibacterial performance on plasma polymerized heptylamine films loaded with silver nanoparticles

    Science.gov (United States)

    Lin, Yu-Chun; Lin, Chia-Chun; Lin, Chih-Hao; Wang, Meng-Jiy

    2017-01-01

    The antibacterial performance of the plasma-polymerized (pp) heptylamine thin films loaded with silver nanoparticles was evaluated against the colonization of Escherichia coli and Staphylococcus aureus. The properties including the thickness and chemical composition of the as deposited HApp films were modulated by adjusting plasma parameters. The acquired results showed that the film thickness was controlled in the range of 20 to 400 nm by adjusting deposition time. The subsequent immersion of the HApp thin films in silver nitrate solutions result in the formation of amine-metal complexes, in which the silver nanoparticles were reduced directly on the matrices to form Ag@HApp. The reduction reaction of silver was facilitated by applying NaBH4 as a reducing agent. The results of physicochemical analyses including morphological analysis and ellipsometry revealed that the silver nanoparticles were successfully reduced on the HApp films, and the amount of reduced silver was closely associated which the thickness of the plasma-polymerized films, the concentration of applied metal ions solutions, and the time of immobilization. Regarding the antibacterial performance, the Ag@HApp films reduced by NaBH4 showed antibacterial abilities of 70.1 and 68.2% against E. coli and S. aureus, respectively.

  5. Localized Polymerization Using Single Photon Photoinitiators in Two-photon process for Fabricating Subwavelength Structures

    CERN Document Server

    Ummethala, Govind; Chaudhary, Raghvendra P; Hawal, Suyog; Saxena, Sumit; Shukla, Shobha

    2016-01-01

    Localized polymerization in subwavelength volumes using two photon dyes has now become a well-established method for fabrication of subwavelength structures. Unfortunately, the two photon absorption dyes used in such process are not only expensive but also proprietary. LTPO-L is an inexpensive, easily available single photon photoinitiator and has been used extensively for single photon absorption of UV light for polymerization. These polymerization volumes however are not localized and extend to micron size resolution having limited applications. We have exploited high quantum yield of radicals of LTPO-Lfor absorption of two photons to achieve localized polymerization in subwavelength volumes, much below the diffraction limit. Critical concentration (10wt%) of LTPO-Lin acrylate (Sartomer) was found optimal to achieve subwavelength localized polymerization and has been demonstrated by fabricating 2D/3D complex nanostructures and functional devices such as variable polymeric gratings with nanoscaled subwavelen...

  6. INTRODUCTION: Nonequilibrium Processes in Plasmas

    Science.gov (United States)

    Petrović, Zoran; Marić, Dragana; Malović, Gordana

    2009-07-01

    This book aims to give a cross section from a wide range of phenomena that, to different degrees, fall under the heading of non-equilibrium phenomenology. The selection is, of course, biased by the interests of the members of the scientific committee and of the FP6 Project 026328 IPB-CNP Reinforcing Experimental Centre for Non-equilibrium Studies with Application in Nano-technologies, Etching of Integrated Circuits and Environmental Research. Some of the papers included here are texts based on selected lectures presented at the Second International Workshop on Non-equilibrium Processes in Plasmas and Environmental Science. However, this volume is not just the proceedings of that conference as it contains a number of papers from authors that did not attend the conference. The goal was to put together a volume that would cover the interests of the project and support further work. It is published in the Institute of Physics journal Journal of Physics: Conference Series to ensure a wide accessibility of the articles. The texts presented here range from in-depth reviews of the current status and past achievements to progress reports of currently developed experimental devices and recently obtained still unpublished results. All papers have been refereed twice, first when speakers were selected based on their reputation and recently published results, and second after the paper was submitted both by the editorial board and individual assigned referees according to the standards of the conference and of the journal. Nevertheless, we still leave the responsibility (and honours) for the contents of the papers to the authors. The papers in this book are review articles that give a summary of the already published work or present the work in progress that will be published in full at a later date (or both). In the introduction to the first volume, in order to show how far reaching, ubiquitous and important non-equilibrium phenomena are, we claimed that ever since the early

  7. Photostability of plasma polymerized γ-terpinene thin films for encapsulation of OPV

    Science.gov (United States)

    Bazaka, Kateryna; Ahmad, Jakaria; Oelgemöller, Michael; Uddin, Ashraf; Jacob, Mohan V.

    2017-03-01

    Optically transparent, smooth, defect-free, chemically inert and with good adhesion to a variety of substrates, plasma polymers from plant-derived secondary metabolites have been identified as promising encapsulating materials for organic electronics and photovoltaics. Here, we demonstrate that an encapsulating layer of plasma polymerized γ-terpinene reduces degradation-related loss in conversion efficiency in PCPDTBT:PC70BM solar cells under ambient operating conditions. The stability of γ-terpinene films was then investigated under extreme UV irradiation conditions as a function of deposition power. When exposed to ambient air, prolonged exposure to UV-A and UV-B light led to notable ageing of the polymer. Photooxidation was identified as the main mechanism of degradation, confirmed by significantly slower ageing when oxygen was restricted through the use of a quartz cover. Under unnatural high-energy UV-C irradiation, significant photochemical degradation and oxidation occurred even in an oxygen-poor environment.

  8. Photostability of plasma polymerized γ-terpinene thin films for encapsulation of OPV

    Science.gov (United States)

    Bazaka, Kateryna; Ahmad, Jakaria; Oelgemöller, Michael; Uddin, Ashraf; Jacob, Mohan V.

    2017-01-01

    Optically transparent, smooth, defect-free, chemically inert and with good adhesion to a variety of substrates, plasma polymers from plant-derived secondary metabolites have been identified as promising encapsulating materials for organic electronics and photovoltaics. Here, we demonstrate that an encapsulating layer of plasma polymerized γ-terpinene reduces degradation-related loss in conversion efficiency in PCPDTBT:PC70BM solar cells under ambient operating conditions. The stability of γ-terpinene films was then investigated under extreme UV irradiation conditions as a function of deposition power. When exposed to ambient air, prolonged exposure to UV–A and UV–B light led to notable ageing of the polymer. Photooxidation was identified as the main mechanism of degradation, confirmed by significantly slower ageing when oxygen was restricted through the use of a quartz cover. Under unnatural high-energy UV–C irradiation, significant photochemical degradation and oxidation occurred even in an oxygen-poor environment. PMID:28358138

  9. Effect of plasma processing reactor circuitry on plasma characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Rauf, S.; Kushner, M.J. [Univ. of Illinois, Urbana, IL (United States). Dept. of Electrical and Computer Engineering

    1997-12-31

    It is well known that external circuitry greatly influences the performance of plasma processing reactors. Simulation of external circuits difficult since the time in which the external circuit attains the steady-state is several orders of magnitude longer than typical plasma simulation time scales. In this paper, the authors present a technique to simulate the external circuit concurrently with the plasma, and implement it into the Hybrid Plasma Equipment Model (HPEM). The resulting model is used to investigate the influence of external circuitry on plasma behavior.

  10. Atomic and molecular processes in fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Janev, R.K. [International Atomic Energy Agency, Vienna (Austria)

    1997-01-01

    The role of atomic and molecular processes in achieving and maintaining the conditions for thermonuclear burn in a magnetically confined fusion plasma is described. Emphasis is given to the energy balance and power and particle exhaust issues. The most important atomic and molecular processes which affect the radiation losses and impurity transport in the core plasma, the neutral particle transport in the plasma edge and the radiative cooling of divertor plasmas are discussed in greater detail. (author)

  11. On the optical and electrical properties of rf and a.c. plasma polymerized aniline thin films

    Indian Academy of Sciences (India)

    U S Sajeev; C Joseph Mathai; S Saravanan; Rajeev R Ashokan; S Venkatachalam; M R Anantharaman

    2006-04-01

    Polyaniline is a widely studied conducting polymer and is a useful material in its bulk and thin film form for many applications, because of its excellent optical and electrical properties. Pristine and iodine doped polyaniline thin films were prepared by a.c. and rf plasma polymerization techniques separately for the comparison of their optical and electrical properties. Doping of iodine was effected in situ. The structural properties of these films were evaluated by FTIR spectroscopy and the optical band gap was estimated from UV-vis-NIR measurements. Comparative studies on the structural, optical and electrical properties of a.c. and rf polymerization are presented here. It has been found that the optical band gap of the polyaniline thin films prepared by rf and a.c. plasma polymerization techniques differ considerably and the band gap is further reduced by in situ doping of iodine. The electrical conductivity measurements on these films show a higher value of electrical conductivity in the case of rf plasma polymerized thin films when compared to the a.c. plasma polymerized films. Also, it is found that the iodine doping enhanced conductivity of the polymer thin films considerably. The results are compared and correlated and have been explained with respect to the different structures adopted under these two preparation techniques.

  12. Plasma Polymerized Thin Films of Maleic Anhydride and 1,2-methylenedioxybenzene for Improving Adhesion to Carbon Surfaces

    DEFF Research Database (Denmark)

    Drews, Joanna Maria; Goutianos, Stergios; Kingshott, Peter

    2007-01-01

    Low power 2-phase AC plasma polymerization has been used to surface modify glassy carbon substrates that are used as an experimental model for carbon fibers in reinforced composites. In order to probe the role of carboxylic acid density on the interfacial adhesion strength a combination...... of different plasma powers and monomer compositions was used. Maleic anhydride (MAR) and 1,2-methylenedioxybenzene (MDOB) were plasma deposited separately and as mixtures to create layers with different surface compositions. In all cases the MAR was hydrolyzed to form carboxylic acid groups. Some carboxylic...... total veflectanc~ Fourier transform infrared spectroscopy. Atomic force microscopy was used to measure the thickness of the plasma films and to monitor the surface roughness for the different polymerization conditions. Finally, preliminary results of fracture energy measurements of the plasma modified...

  13. Water sorption of heat-polymerized acrylic resins processed in mono and bimaxillary flasks

    OpenAIRE

    Meloto, Carolina B.; Silva-Concílio,Laís R.; Machado, Cristiane; Ribeiro,Margarete C.; Joia,Fábio A.; Rizzatti-Barbosa,Célia M.

    2006-01-01

    This study evaluated water sorption in heat-polymerized acrylic resins processed in monomaxillary flasks by water bath and in bimaxillary flasks by microwave energy and water bath. Fifty heat-polymerized acrylic resin specimens were fabricated according to the 12th specification of the American Dental Association and assigned to 3 groups: group 1 was processed by water bath in monomaxillary metallic flask; group 2 was processed by microwave energy in bimaxillary PVC flask; and group 3 was pro...

  14. Improvement of Strength Characteristics of Aerospace Fiber Reinforced Composite Materials using Atmospheric Pressure Plasma-Graft Polymerization Treatment

    Science.gov (United States)

    Aoi, Tatsuji; Kuroki, Tomoyuki; Tahara, Mitsuru; Okubo, Masaaki

    The atmospheric pressure nonthermal plasma-graft polymerization treatment is applied for the surface modification of the organic fibers in order to enhance the strength of the aerospace structural composite material consisting of the laminated textiles. The influence of the treatment on the composite materials' strength properties is examined. As a result, the plasma-graft polymerization surface treatment is effective for the compression and bend of the composite materials. Because the interfacial bonding between each fiber and matrix resin is strengthened by the treatment, the strengths of the composite materials are increased.

  15. Isolation of bovine plasma albumin by liquid chromatography and its polymerization for use in immunohematology

    Directory of Open Access Journals (Sweden)

    K. Tanaka

    2001-08-01

    Full Text Available The aim of the method described here is to remove hemoglobin, the major contaminant in the bovine plasma obtained from slaughterhouses, by adding a mixture of 19% cold ethanol and 0.6% chloroform, followed by fibrinogen and globulin precipitation by the Cohn method and nonspecific hemagglutinin by thermocoagulation. The experimental volume of bovine plasma was 2,000 ml per batch. Final purification was performed by liquid chromatography using the ion-exchange gel DEAE-Sepharose FF. The bovine albumin thus obtained presented > or = 99% purity, a yield of 25.0 ± 1.2 g/l plasma and >71.5% recovery. N-acetyl-DL-tryptophan (0.04 mmol/g protein and sodium caprylate (0.04 mmol/g protein were used as stabilizers and the final concentration of albumin was adjusted to 22.0% (w/v, pH 7.2 to 7.3. Viral inactivation was performed by pasteurization for 10 h at 60°C. The bovine albumin for the hemagglutination tests used in immunohematology was submitted to chemical treatment with 0.06% (w/v glutaraldehyde and 0.1% (w/v formaldehyde at 37°C for 12 h to obtain polymerization. A change in molecular distribution was observed after this treatment, with average contents of 56.0% monomers, 23.6% dimers, 12.2% trimers and 8.2% polymers. The tests performed demonstrated that this polymerized albumin enhances the agglutination of Rho(D-positive red cells by anti-Rho(D serum, permitting and improving visualization of the results.

  16. Deposition of plasma polymerized perfluoromethylene-dominated films showing oil-repellency

    Science.gov (United States)

    Chase, J. E.; Boerio, F. J.

    2003-05-01

    Plasma polymerized fluorocarbon films were deposited onto polyethylene (PE) substrates to increase oil-repellency of PE. Depositions were performed using the monomer, 1H,1H,2H-perfluoro-1-dodecene in a parallel-plate, radio frequency (rf) reactor, with variable continuous-wave power ranging from 2 to 160 W. The film deposition rate and morphology were strongly dependent on the applied rf power. Most importantly, the chemical structure of the deposited films was also altered, resulting in changes in contact angles of various liquids and the surface energy. Films deposited at low power were composed mainly of perfluoromethylene (CF2) species (up to 67.2%), as shown by x-ray photoelectron spectroscopy (XPS). With an increase in rf power, CF2 content in the film decreased as further fragmentation of the monomer occurred. For each deposition at varying rf powers, even at powers as low as 2 W, the C=C and C-H bonds in the monomer were dissociated by the plasma and not incorporated into the films, as shown by Fourier transform infrared spectroscopy. Oil-repellency, as shown by increased contact angles of hydrocarbon liquids, was found to increase as the amount of CF2 species increased in the film structure. A low critical surface energy (2.7 mJ/m2) was calculated for the film deposited with only 2 W of rf power. Adhesion of the plasma-polymerized films to the PE was also evaluated and found to be poor for films with a high concentration of CF2 species, where cohesive failure within the film occurred. However, adhesion increased as a function of rf power, where the film structure showed more cross-linking. There was a compromise between producing a film with high oleophobicity (oil-repellency) while maintaining adhesion of the film to PE, as some disruption of the CF2 chains in the films was necessary for cohesion through cross-linking.

  17. Studies in reactive extrusion processing of biodegradable polymeric materials

    Science.gov (United States)

    Balakrishnan, Sunder

    Various reaction chemistries such as Polymerization, Polymer cross-linking and Reactive grafting were investigated in twin-screw extruders. Poly (1,4-dioxan-2-one) (PPDX) was manufactured in melt by the continuous polymerization of 1,4-dioxan-2-one (PDX) monomer in a twin-screw extruder using Aluminum tri-sec butoxide (ATSB) initiator. Good and accurate control over molecular weight was obtained by controlling the ratio of monomer to initiator. A screw configuration consisting of only conveying elements was used for the polymerization. The polymerization reaction was characterized by a monomer-polymer dynamic equilibrium, above the melting temperature of the polymer, limiting the equilibrium conversion to 78-percent. Near complete (˜100-percent) conversion was obtained on co-polymerizing PDX monomer with a few mol-percent (around 8-percent) Caprolactone (CL) monomer in a twin-screw extruder using ATSB initiator. The co-polymers exhibited improved thermal stability with reduction in glass transition temperature. The extruder was modeled as an Axial Dispersed Plug Flow Reactor for the polymerization of CL monomer using Residence Time Distribution (RTD) Analysis. The model provided a good fit to the experimental RTD and conversion data. Aliphatic and aliphatic-aromatic co-polyesters, namely Polycaprolactone (PCL) and Poly butylenes (adipate-co-terephthalate) (Ecoflex) were cross-linked in a twin-screw extruder using radical initiator to form micro-gel reinforced biodegradable polyesters. Cross-linked Ecoflex was further extrusion blended with talc to form blends suitable to be blown into films. A screw configuration consisting of conveying and kneading elements was found to be effective in dispersion of the talc particles (5--10 microns) in the polyester matrix. While the rates of crystallization increased for the talc filled polyester blends, overall crystallinity reduced. Mechanical, tear and puncture properties of films made using the talc filled polyester blends

  18. Enhanced corrosion resistance and hemocompatibility of biomedical NiTi alloy by atmospheric-pressure plasma polymerized fluorine-rich coating

    Energy Technology Data Exchange (ETDEWEB)

    Li, Penghui; Li, Limin [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Wang, Wenhao [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Division of Spine Surgery, Department of Orthopaedics and Traumatology, Pokfulam, Hong Kong (China); Jin, Weihong [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Liu, Xiangmei [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei University, Wuhan, Hubei 430062 (China); Yeung, Kelvin W.K. [Division of Spine Surgery, Department of Orthopaedics and Traumatology, Pokfulam, Hong Kong (China); Chu, Paul K., E-mail: paul.chu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

    2014-04-01

    Highlights: • Fluoropolymer is deposited on NiTi alloy via atmospheric-pressure plasma polymerization. • The corrosion resistance of NiTi alloy in SBF and DMEM is evidently improved. • The adsorption ratio of albumin to fibrinogen is increased on the coated surface. • The reduced platelet adhesion number indicates better in vitro hemocompatibility. - Abstract: To improve the corrosion resistance and hemocompatibility of biomedical NiTi alloy, hydrophobic polymer coatings are deposited by plasma polymerization in the presence of a fluorine-containing precursor using an atmospheric-pressure plasma jet. This process takes place at a low temperature in air and can be used to deposit fluoropolymer films using organic compounds that cannot be achieved by conventional polymerization techniques. The composition and chemical states of the polymer coatings are characterized by fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The corrosion behavior of the coated and bare NiTi samples is assessed and compared by polarization tests and electrochemical impedance spectroscopy (EIS) in physiological solutions including simulated body fluids (SBF) and Dulbecco's Modified Eagle's medium (DMEM). The corrosion resistance of the coated NiTi alloy is evidently improved. Protein adsorption and platelet adhesion tests reveal that the adsorption ratio of albumin to fibrinogen is increased and the number of adherent platelets on the coating is greatly reduced. The plasma polymerized coating renders NiTi better in vitro hemocompatibility and is promising as a protective and hemocompatible coating on cardiovascular implants.

  19. Plasma chemistry study of PLAD processes

    Energy Technology Data Exchange (ETDEWEB)

    Qin Shu; Brumfield, Kyle; Liu, Lequn Jennifer; Hu, Yongjun Jeff; McTeer, Allen; Hsu, Wei Hui; Wang Maoying [Nanya Technology Inc., Santa Clara, CA 95054 (United States); Micron Technology Inc., Boise, ID 83707 (United States)

    2012-11-06

    Plasma doping (PLAD) shows very different impurity profiles compared to the conventional beam-line-based ion implantations due to its non-mass separation property and plasma environment. There is no simulation for PLAD process so far due to a lack of a dopant profile model. Several factors determine impurity profiles of PLAD process. The most significant factors are: plasma chemistry and deposition/etching characteristics of multi-ion species plasmas. In this paper, we present plasma chemistry and deposition/etching characteristics of PLAD processes versus co-gas dilutions. Four dopant plasmas including B{sub 2}H{sub 6}, BF{sub 3}, AsH{sub 3}, and PH{sub 3}, and two non-dopant plasmas including CH{sub 4} and GeH{sub 4} are studied and demonstrated.

  20. Plasma energy recycle and conversion of polymeric (MSW) waste. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Knight, Richard; Grossman, Elihu D.

    2000-12-05

    Final report summarizing research project results of studies of the thermal plasma recycling of polymers, including polyethylene and polypropylene. High levels of recovery of monomers were obtained from the process developed under this study.

  1. Surface modification of SERS substrates with plasma-polymerized trimethylsilane nanocoating

    Science.gov (United States)

    Kim, Young Jo; Sun, Xin; Jones, John E.; Lin, Mengshi; Yu, Qingsong; Li, Hao

    2015-03-01

    Surface-enhanced Raman scattering (SERS) substrates were modified by depositing a nanometer-thick polymer coating on top of SERS-active surface. This thin hydrophobic nanocoating, achieved by low temperature plasma polymerization of trimethylsilane, was found to reduce surface energy of SERS substrate and in turn help relieve the analyte spreading on the surface of SERS substrates. Detection of melamine molecules with these surface-modified SERS substrates showed that this plasma nanocoating improved, not significantly though, SERS sensitivity in comparison with unmodified SERS substrates. It is believed that the increased hydrophobicity induced by this plasma nanocoating had two folds of beneficial effects on SERS sensitivity. First, the as-produced hydrophobic surface gave rise to preconcentration effect due to the reduced contact area between analyte molecules and the substrate surface. Second, the decreased surface energy of SERS substrates was helpful in placing analyte molecules in SERS hot spots. These two combined gains were deemed to outweigh the loss of SERS sensitivity caused by enlarged distance between metal surface and analyte molecules.

  2. Varying stress of SiOsub>xsub>Csub>ysub> thin films deposited by plasma polymerization.

    Science.gov (United States)

    Liao, Wei-Bo; Chang, Ya-Chen; Jaing, Cheng-Chung; Cheng, Ching-Long; Lee, Cheng-Chung; Wei, Hung-Sen; Kuo, Chien-Cheng

    2017-02-01

    SiOsub>xsub>Csub>ysub> thin films were deposited by plasma polymerization. The stress of the deposited SiOsub>xsub>Csub>ysub> thin films can be modified by adjusting the beam current, the anode voltage, and the flow rate of hexamethyldisiloxane (HMDSO) gas and oxygen. Reducing the beam current or increasing the flow rate of HMDSO gas increased the linear/cage structure ratio and turned the stress of the SiOsub>xsub>Csub>ysub> thin films from compressive to tensile. The linear/cage structure ratio can be adjusted by changing the composite parameter, W[FM]sub>csub>/[FM]sub>msub>, to control the stress of the deposited plasma polymer films. Multilayers of TiOsub>2sub>/SiOsub>2sub>/TiOsub>2sub> were coated on a SiOsub>xsub>Csub>ysub> plasma polymer film herein, reducing their stress by 70% from 0.06 to 0.018 GPa. The refractive index is 1.55, and the absorption coefficient is less than 10-4 at 550 nm of the SiOsub>xsub>Csub>ysub> films. Superior optical performances of SiOsub>xsub>Csub>ysub> thin films make their use in optical thin films.

  3. High throughput atmospheric pressure plasma-induced graft polymerization for identifying protein-resistant surfaces.

    Science.gov (United States)

    Gu, Minghao; Kilduff, James E; Belfort, Georges

    2012-02-01

    Three critical aspects of searching for and understanding how to find highly resistant surfaces to protein adhesion are addressed here with specific application to synthetic membrane filtration. They include the (i) discovery of a series of previously unreported monomers from a large library of monomers with high protein resistance and subsequent low fouling characteristics for membrane ultrafiltration of protein-containing fluids, (ii) development of a new approach to investigate protein-resistant mechanisms from structure-property relationships, and (iii) adaptation of a new surface modification method, called atmospheric pressure plasma-induced graft polymerization (APP), together with a high throughput platform (HTP), for low cost vacuum-free synthesis of anti-fouling membranes. Several new high-performing chemistries comprising two polyethylene glycol (PEG), two amines and one zwitterionic monomers were identified from a library (44 commercial monomers) of five different classes of monomers as strong protein-resistant monomers. Combining our analysis here, using the Hansen solubility parameters (HSP) approach, and data from the literature, we conclude that strong interactions with water (hydrogen bonding) and surface flexibility are necessary for producing the highest protein resistance. Superior protein-resistant surfaces and subsequent anti-fouling performance was obtained with the HTP-APP as compared with our earlier HTP-photo graft-induced polymerization (PGP).

  4. Moisture resistant and anti-reflection optical coatings produced by plasma polymerization of organic compounds

    Science.gov (United States)

    Hollahan, J. R.; Wydeven, T.

    1975-01-01

    The need for protective coatings on critical optical surfaces, such as halide crystal windows or lenses used in spectroscopy, has long been recognized. It has been demonstrated that thin, one micron, organic coatings produced by polymerization of flourinated monomers in low temperature gas discharge (plasma) exhibit very high degrees of moisture resistence, e.g., hundreds of hours protection for cesium iodide vs. minutes before degradation sets in for untreated surfaces. The index of refraction of these coatings is intermediate between that of the halide substrate and air, a condition for anti-reflection, another desirable property of optical coatings. Thus, the organic coatings not only offer protection, but improved transmittance as well. The polymer coating is non-absorbing over the range 0.4 to 40 microns with an exception at 8.0 microns, the expected absorption for C-F bonds.

  5. Combining On-Line Characterization Tools with Modern Software Environments for Optimal Operation of Polymerization Processes

    Directory of Open Access Journals (Sweden)

    Navid Ghadipasha

    2016-02-01

    Full Text Available This paper discusses the initial steps towards the formulation and implementation of a generic and flexible model centric framework for integrated simulation, estimation, optimization and feedback control of polymerization processes. For the first time it combines the powerful capabilities of the automatic continuous on-line monitoring of polymerization system (ACOMP, with a modern simulation, estimation and optimization software environment towards an integrated scheme for the optimal operation of polymeric processes. An initial validation of the framework was performed for modelling and optimization using literature data, illustrating the flexibility of the method to apply under different systems and conditions. Subsequently, off-line capabilities of the system were fully tested experimentally for model validations, parameter estimation and process optimization using ACOMP data. Experimental results are provided for free radical solution polymerization of methyl methacrylate.

  6. Functionalized ormosil scaffolds processed by direct laser polymerization for application in tissue engineering

    DEFF Research Database (Denmark)

    Matei, A.; Schou, Jørgen; Canulescu, Stela

    2013-01-01

    modified either by low pressure argon plasma treatment or by covering the structures with two different proteins (lysozyme, fibrinogen). For improved adhesion, the proteins were deposited by matrix assisted pulsed laser evaporation technique. The functionalized structures were tested in mouse fibroblasts......Synthesized N,N′-(methacryloyloxyethyl triehtoxy silyl propyl carbamoyl-oxyhexyl)-urea hybrid methacrylate was polymerized by direct laser polymerization using femtosecond laser pulses with the aim of using it for subsequent applications in tissue engineering. The as-obtained scaffolds were...

  7. Functionalized Ormosil Scaffolds Processed by Direct Laser Polymerization for Application in Tissue Engineering

    DEFF Research Database (Denmark)

    Matei, A.; Schou, Jørgen; Canulescu, Stela

    The N,N’-(methacryloyloxyethyl triehtoxy silyl propyl carbamoyl-oxyhexyl)-urea hybrid methacrylate for applications in tissue engineering was synthesized and afterwards polymerized by direct laser polymerization using femtosecond laser pulses with the aim of using it for further applications...... in tissue engineering. The as-obtained scaffolds were modified either by low pressure argon plasma treatment or by using two different proteins (lysozyme, fibrinogen). For improved adhesion, the proteins were deposited by matrix assisted pulsed laser evaporation. The functionalized structures were tested...

  8. Functionalized ormosil scaffolds processed by direct laser polymerization for application in tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Matei, A., E-mail: andreeapurice@nipne.ro [Petru Poni Institute of Macromolecular Chemistry, Grigore Ghica Voda 41A, 6600 Iasi (Romania); National Institute for Lasers, Plasma and Radiation Physics, Atomistilor 409, 77125 Bucharest-Magurele (Romania); Schou, J.; Canulescu, S. [DTU Fotonik, Risø Campus, Technical University of Denmark, DK-4000 Roskilde (Denmark); Zamfirescu, M.; Albu, C.; Mitu, B. [National Institute for Lasers, Plasma and Radiation Physics, Atomistilor 409, 77125 Bucharest-Magurele (Romania); Buruiana, E.C.; Buruiana, T. [Petru Poni Institute of Macromolecular Chemistry, Grigore Ghica Voda 41A, 6600 Iasi (Romania); Mustaciosu, C.; Petcu, I. [Department of Environmental and Life Physics, National Institute for Physics and Nuclear Engineering ‘Horia Hulubei’, Bucharest (Romania); Dinescu, M. [National Institute for Lasers, Plasma and Radiation Physics, Atomistilor 409, 77125 Bucharest-Magurele (Romania)

    2013-08-01

    Synthesized N,N′-(methacryloyloxyethyl triehtoxy silyl propyl carbamoyl-oxyhexyl)-urea hybrid methacrylate was polymerized by direct laser polymerization using femtosecond laser pulses with the aim of using it for subsequent applications in tissue engineering. The as-obtained scaffolds were modified either by low pressure argon plasma treatment or by covering the structures with two different proteins (lysozyme, fibrinogen). For improved adhesion, the proteins were deposited by matrix assisted pulsed laser evaporation technique. The functionalized structures were tested in mouse fibroblasts culture and the cells morphology, proliferation, and attachment were analyzed.

  9. Plasma polymerization of acetylene onto silica: an approach to control the distribution of silica in single elastomers and immiscible blends

    NARCIS (Netherlands)

    Tiwari, M.; Noordermeer, J.W.M.; Ooij, W.J.; Dierkes, W.K.

    2008-01-01

    Surface modification of silica by acetylene plasma polymerization is applied in order to improve the dispersion in and compatibility with single rubbers and their blends. Silica, used as a reinforcing filler for elastomers, is coated with a polyacetylene (PA) film under vacuum conditions. Water pene

  10. Characterization and protein-adsorption behavior of deposited organic thin film onto titanium by plasma polymerization with hexamethyldisiloxane.

    Science.gov (United States)

    Hayakawa, Tohru; Yoshinari, Masao; Nemoto, Kimiya

    2004-01-01

    Plasma polymerized hexamethyldisiloxane (HMDSO) thin film was deposited onto titanium using a radio-frequency apparatus for the surface modification of titanium. A titanium disk was first polished using colloidal silica at pH=9.8. Plasma-polymerized HMDSO films were firmly attached to the titanium by heating the titanium to a temperature of approximately 250 degrees C. The thickness of the deposited film was 0.07-0.35mum after 10-60min of plasma polymerization. The contact angle with respect to double distilled water significantly increased after HMDSO coating. X-ray photoelectron spectroscopy revealed that the deposited thin film consisted of Si, C, and O atoms. No Ti peaks were observed on the deposited surface. The deposited HMDSO film was stable during 2-weeks immersion in phosphate buffer saline solution. Fourier transform reflection-absorption spectroscopy showed the formation of Si-H, Si-C, C-H, and Cz.dbnd6;O bonds in addition to Si-O-Si bonds. Quartz crystal microbalance-dissipation measurement demonstrated that the deposition of HMDSO thin films on titanium has a benefit for fibronectin adsorption at the early stage. In conclusion, plasma polymerization is a promising technique for the surface modification of titanium. HMDSO-coated titanium has potential application as a dental implant material.

  11. Atmospheric Pressure Plasma Process And Applications

    Energy Technology Data Exchange (ETDEWEB)

    Peter C. Kong; Myrtle

    2006-09-01

    This paper provides a general discussion of atmospheric-pressure plasma generation, processes, and applications. There are two distinct categories of atmospheric-pressure plasmas: thermal and nonthermal. Thermal atmospheric-pressure plasmas include those produced in high intensity arcs, plasma torches, or in high intensity, high frequency discharges. Although nonthermal plasmas are at room temperatures, they are extremely effective in producing activated species, e.g., free radicals and excited state atoms. Thus, both thermal and nonthermal atmosphericpressure plasmas are finding applications in a wide variety of industrial processes, e.g. waste destruction, material recovery, extractive metallurgy, powder synthesis, and energy conversion. A brief discussion of recent plasma technology research and development activities at the Idaho National Laboratory is included.

  12. Tribological behavior of plasma-polymerized aminopropyltriethoxysilane films deposited on thermoplastic elastomers substrates

    Energy Technology Data Exchange (ETDEWEB)

    Alba-Elías, Fernando, E-mail: fernando.alba@unirioja.es [Department of Mechanical Engineering, University of La Rioja, c/Luis de Ulloa 20, 26004 Logroño, La Rioja (Spain); Sainz-García, Elisa; González-Marcos, Ana [Department of Mechanical Engineering, University of La Rioja, c/Luis de Ulloa 20, 26004 Logroño, La Rioja (Spain); Ordieres-Meré, Joaquín [ETSII, Polytechnic University of Madrid, c/José Gutiérrez Abascal 2, 28006 Madrid (Spain)

    2013-07-01

    Thermoplastic elastomers (TPE) are multifunctional polymeric materials that are characterized by moderate cost, excellent mechanical properties (high elasticity, good flexibility, hardness, etc.), high tensile strength, oxidation and wettability. With an objective of reducing the superficial friction coefficient of TPE, this work analyzes the characteristics of coating films that are based on aminopropyltriethoxysilane (APTES) over a TPE substrate. Since this material is heat-sensitive, it is necessary to use a technology that permits the deposition of coatings at low temperatures without affecting the substrate integrity. Thus, an atmospheric-pressure plasma jet system (APPJ) with a dielectric barrier discharge (DBD) was used in this study. The coated samples were analyzed by Scanning Electron Microscopy, Atomic Force Microscopy, Fourier-Transform Infrared with Attenuated Total Reflectance Spectroscopy, X-ray Photoelectron Spectroscopy and tribological tests (friction coefficient and wear rate). The studies showed that the coated samples that contain a higher amount of forms of silicon (SiOSi) and nitrogen (amines, amides and imines) have lower friction coefficients. The sample coated at a specific plasma power of 550 W and an APTES flow rate of 1.5 slm had the highest values of SiOSi and nitrogen-containing groups peak intensity and atomic percentages of Si2p and SiO{sub 4}, and the lowest percentages of C1s and average friction coefficient. The results of this research permit one to conclude that APPJ with a DBD is a promising technique to use in coating SiO{sub x} and nitrogen-containing groups layers on polymeric materials. - Highlights: • SiO{sub x} thin films on thermoplastic elastomers by atmospheric pressure plasma jet. • Study of influence of plasma power and precursor flow rate on film's properties. • Friction coefficient is inversely related to the amount of SiOSi and N groups. • Nitrogen groups from the ionization gas (N{sub 2}) seem to

  13. Deposition of stable amine coating onto polycaprolactone nanofibers by low pressure cyclopropylamine plasma polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Manakhov, Anton [Plasma Technologies, CEITEC — Central European Institute of Technology, Masaryk University, Kotlářská 2, Brno 61137 (Czech Republic); Nečas, David [Plasma Technologies, CEITEC — Central European Institute of Technology, Masaryk University, Kotlářská 2, Brno 61137 (Czech Republic); Department of Physical Electronics, Faculty of Science, Masaryk University, Kotlářská 2, Brno 61137 (Czech Republic); Čechal, Jan [CEITEC — Central European Institute of Technology, Brno University of Technology, Technická 3058/10, 616 00 Brno (Czech Republic); Pavliňák, David [Department of Physical Electronics, Faculty of Science, Masaryk University, Kotlářská 2, Brno 61137 (Czech Republic); Eliáš, Marek [Plasma Technologies, CEITEC — Central European Institute of Technology, Masaryk University, Kotlářská 2, Brno 61137 (Czech Republic); Department of Physical Electronics, Faculty of Science, Masaryk University, Kotlářská 2, Brno 61137 (Czech Republic); and others

    2015-04-30

    Amine-rich films are of high interest for the bio-applications including drug delivery and tissue engineering thanks to their high reactivity allowing the formation of the covalent linkages between biomolecules and a surface. However, the bio-applications of amine-rich films require their good stability in water which is often achieved at large expenses of the amine concentration. Recently, non-toxic cyclopropylamine (CPA) has been applied for the plasma polymerization of films bearing high NH{sub x} environment combined with the moderate thickness loss (20%) after water immersion for 48 h. In this work, the amine-rich film with the NH{sub x} concentration over 7 at.% was deposited on Si substrates and polycaprolactone nanofiber meshes by using CPA plasma polymerization (pulsed mode) in a vertically oriented stainless steel reactor. The substrates were placed at the radio frequency electrode and the ion bombardment caused by direct-current self-bias was suppressed by using high pressure of 50 Pa. Analysis of samples by scanning electron microscopy did not reveal any cracks in the deposited layer formed during a sample immersion in water. Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) confirmed a slight oxidation of amine groups in water but the film still contained 5 at.% of NH{sub x} (according to the N1s XPS fitting) after the immersion. The rapid oxidation of amine groups was observed during the aging experiment carried out in air at room temperature because FTIR revealed an increase of amide peaks that increased progressively with aging time. However, this oxidation was significantly reduced if the plasma polymer was stored at − 20 °C. Since the films exhibit high amine concentration and very good water stability they have great potential for applications as biocompatible functional coatings. - Highlights: • Cyclopropylamine plasma polymers deposited on polycaprolactone nanofibers • Amine-rich films with high

  14. Cold plasma processing to improve food safety

    Science.gov (United States)

    Cold plasma is an antimicrobial process being developed for application as a food processing technology. This novel intervention is the subject of an expanding research effort by groups around the world. A variety of devices can be used to generate cold plasma and apply it to the food commodity bein...

  15. Polymerization by plasma of trichloroethylene by means of resistive and inductive coupling; Polimerizacion por plasmas de tricloroetileno por medio de acoplamiento resistivo e inductivo

    Energy Technology Data Exchange (ETDEWEB)

    Vasquez, M.; Cruz, G.; Olayo, M.G. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Timoshina, T. [IPN, ESIQIE, 07738 Mexico D.F. (Mexico); Morales, J.; Olayo, R. [UAM-I, 09340 Mexico D.F. (Mexico)

    2004-07-01

    It was carried out the polymerization for plasma of the trichloroethylene by means of two types of coupling, resistive and inductive with the objective of studying the structure, morphology and the electric properties of the polymers obtained under these conditions. The structure and morphology of the polymers were studied by means of EDS and FT-IR spectroscopies. (Author)

  16. Surface functionalization of an osteoconductive filler by plasma polymerization of poly(ε-caprolactone) and poly(acrylic acid) films

    Science.gov (United States)

    Petisco-Ferrero, S.; Sánchez-Ilárduya, M. B.; Díez, A.; Martín, L.; Meaurio Arrate, E.; Sarasua, J. R.

    2016-11-01

    One of the major limitations found in the use of nanocomposites based on synthetic hydroxyapatite and polymeric matrix for bone-tissue regeneration lies in the poor interfacial adhesion between the inorganic filler and the polymer matrix. The integrity of the nanocomposite is severely compromised since, on the one hand, high surface fillers tend to form aggregates and on the other, there is no chemical bonding between these two different categories of materials. Thus, customized surface functionalization stands as an effective route to improve the interfacial behaviour between particles and polymeric matrices. Amongst the current state of development of coating technologies, the high film-chemistry controllability offered by plasma polymerization technology enhances the synthesis of polymeric films from virtually any starting organic monomer. In this sense, the work presented here provides strong evidences of surface functionalization achieved by plasma polymerization starting respectively from ε-caprolactone and acrylic acid monomers. The chemistry of the deposited films has been descriptively analysed by XPS demonstrating outstanding retention of monomer functionalities and FTIR spectra of the deposited films revealed a high resemblance to those obtained by conventional synthesis. Results provided thereof are expected to significantly contribute to improve the interfacial behaviour in terms of matrix-reinforcement compatibilization, of crucial importance for bone-tissue engineering applications.

  17. Tailoring Surface Properties of Polymeric Separators for Lithium-Ion Batteries by 13.56 MHz Radio-Frequency Plasma Glow Discharge

    Science.gov (United States)

    Liang, Chia-Han; Juang, Ruey-Shin; Tsai, Ching-Yuan; Huang, Chun

    2013-11-01

    The hydrophilic surface modification of the polymeric separator is achieved by low-pressure 13.56 MHz radio-frequency Ar and He gas plasma treatments. The changes in surface hydrophilicity and surface free energy were examined by static contact angle analysis. The static water contact angle of the plasma-modified polymeric separator particularly decreased with the increase in treatment time. An obvious increase in the surface energy of polymeric separators owing to the crosslinking by activated species of inert gases effect of monatomic-gas-plasma treatments was also observed. Optical emission spectroscopy was carried out to analyze the chemical species generated after Ar and He gas plasma treatments. The variations in the surface morphology and chemical structure of the polymeric separators were confirmed by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy (XPS) measurements. XPS analysis showed significantly higher surface concentrations of oxygen functional groups for monatomic-gas-plasma-modified polymeric separator surfaces than for the unmodified polymeric separator surface. The experimental results show the important role of chemical species in the interaction between Ar and He gas plasmas and the polymeric separator surface, which can be controlled by surface modification to tailor the hydrophilicity of the polymeric separator.

  18. Plasma nanotextured polymeric lab-on-a-chip for highly efficient bacteria capture and lysis.

    Science.gov (United States)

    Tsougeni, K; Papadakis, G; Gianneli, M; Grammoustianou, A; Constantoudis, V; Dupuy, B; Petrou, P S; Kakabakos, S E; Tserepi, A; Gizeli, E; Gogolides, E

    2016-01-07

    We describe the design, fabrication, and successful demonstration of a sample preparation module comprising bacteria cell capture and thermal lysis on-chip with potential applications in food sample pathogen analysis. Plasma nanotexturing of the polymeric substrate allows increase of the surface area of the chip and the antibody binding capacity. Three different anti-Salmonella antibodies were directly and covalently linked to plasma treated chips without any additional linker chemistry or other treatment. Then, the Ab-modified chips were tested for their capacity to bind bacteria in the concentration range of 10(2)-10(8) cells per mL; the module exhibited 100% efficiency in Salmonella enterica serovar Typhimurium bacteria capture for cell suspensions below 10(5) cells per mL (10(4) cells injected with a 100 μL sample volume) and efficiency higher than 50% for 10(7) cells per mL. Moreover, thermal lysis achieved on-chip from as low as 10 captured cells was demonstrated and shown to compare well with off-chip lysis. Excellent selectivity (over 1 : 300) was obtained in a sample containing, in addition to S. Typhimurium and E. coli bacteria.

  19. Conformal encapsulation of three-dimensional, bioresorbable polymeric scaffolds using plasma-enhanced chemical vapor deposition.

    Science.gov (United States)

    Hawker, Morgan J; Pegalajar-Jurado, Adoracion; Fisher, Ellen R

    2014-10-21

    Bioresorbable polymers such as poly(ε-caprolactone) (PCL) have a multitude of potential biomaterial applications such as controlled-release drug delivery and regenerative tissue engineering. For such biological applications, the fabrication of porous three-dimensional bioresorbable materials with tunable surface chemistry is critical to maximize their surface-to-volume ratio, mimic the extracellular matrix, and increase drug-loading capacity. Here, two different fluorocarbon (FC) precursors (octofluoropropane (C3F8) and hexafluoropropylene oxide (HFPO)) were used to deposit FC films on PCL scaffolds using plasma-enhanced chemical vapor deposition (PECVD). These two coating systems were chosen with the intent of modifying the scaffold surfaces to be bio-nonreactive while maintaining desirable bulk properties of the scaffold. X-ray photoelectron spectroscopy showed high-CF2 content films were deposited on both the exterior and interior of PCL scaffolds and that deposition behavior is PECVD system specific. Scanning electron microscopy data confirmed that FC film deposition yielded conformal rather than blanket coatings as the porous scaffold structure was maintained after plasma treatment. Treated scaffolds seeded with human dermal fibroblasts (HDF) demonstrate that the cells do not attach after 72 h and that the scaffolds are noncytotoxic to HDF. This work demonstrates conformal FC coatings can be deposited on 3D polymeric scaffolds using PECVD to fabricate 3D bio-nonreactive materials.

  20. Pulsed Plasma Polymerization of Perfluorooctyl Ethylene for Transparent Hydrophobic Thin Coatings

    Science.gov (United States)

    Liu, Xiaojun; Wang, Lei; Hao, Jie; Chu, Liqiang

    2015-12-01

    Herein we report on the deposition of transparent hydrophobic thin coatings by radio frequency plasma polymerization (PP) of perfluorooctyl ethylene (PFOE) in both pulsed and continuous wave (CW) modes. The chemical compositions of the resulting PP-PFOE coatings were confirmed by means of Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The thicknesses and surface morphologies of the coatings were examined using surface plasmon resonance spectroscopy and atomic force microscopy. The surface wetting properties and optical transmittance were measured using a water contact angle goniometer and UV-vis spectroscopy. The FT-IR and XPS data showed that the PP-PFOE coatings deposited in the pulsed mode had a higher retention of CF2 groups compared to those from the CW mode. While the water contact angle of the freshly deposited PP-PFOE from the pulsed mode showed a decrease from 120 degrees to 111 degrees in the first two days, it then remained almost unchanged up to 45 days. The UV-vis data indicated that a PP-PFOE coating 30.6 nm thick had a light transmittance above 90% in the UV and visible ranges. The deposition rates under various plasma conditions are also discussed. supported by the Tianjin Research Program of Application Foundation and Advanced Technology, China (No. 12JCYBJC31700) and the Program for New Century Excellent Talents in University, China (No. NCET-12-1064)

  1. Atomic processes in optically thin plasmas

    Science.gov (United States)

    Kaastra, Jelle S.; Gu, Liyi; Mao, Junjie; Mehdipour, Missagh; Raassen, Ton; Urdampilleta, Igone

    2016-10-01

    The Universe contains a broad range of plasmas with quite different properties depending on distinct physical processes. In this contribution we give an overview of recent developments in modeling such plasmas with a focus on X-ray emission and absorption. Despite the fact that such plasmas have been investigated already for decades, and that overall there is a good understanding of the basic processes, there are still areas, where improvements have to be made that are important for the analysis of astrophysical plasmas. We present recent work on the update of atomic parameters in the codes that describe the emission from collisional plasmas, where older approximations are being replaced now by more accurate data. Further we discuss the development of models for photo-ionised plasmas in the context of outflows around supermassive black holes and models for charge transfer that are needed for analyzing the data from the upcoming ASTRO-H satellite.

  2. Nonthermal plasma technology as a versatile strategy for polymeric biomaterials surface modification: a review.

    Science.gov (United States)

    Desmet, Tim; Morent, Rino; De Geyter, Nathalie; Leys, Christophe; Schacht, Etienne; Dubruel, Peter

    2009-09-14

    In modern technology, there is a constant need to solve very complex problems and to fine-tune existing solutions. This is definitely the case in modern medicine with emerging fields such as regenerative medicine and tissue engineering. The problems, which are studied in these fields, set very high demands on the applied materials. In most cases, it is impossible to find a single material that meets all demands such as biocompatibility, mechanical strength, biodegradability (if required), and promotion of cell-adhesion, proliferation, and differentiation. A common strategy to circumvent this problem is the application of composite materials, which combine the properties of the different constituents. Another possible strategy is to selectively modify the surface of a material using different modification techniques. In the past decade, the use of nonthermal plasmas for selective surface modification has been a rapidly growing research field. This will be the highlight of this review. In a first part of this paper, a general introduction in the field of surface engineering will be given. Thereafter, we will focus on plasma-based strategies for surface modification. The purpose of the present review is twofold. First, we wish to provide a tutorial-type review that allows a fast introduction for researchers into the field. Second, we aim to give a comprehensive overview of recent work on surface modification of polymeric biomaterials, with a focus on plasma-based strategies. Some recent trends will be exemplified. On the basis of this literature study, we will conclude with some future trends for research.

  3. A plasma process monitor/control system

    Energy Technology Data Exchange (ETDEWEB)

    Stevenson, J.O.; Ward, P.P.; Smith, M.L. [Sandia National Labs., Albuquerque, NM (United States); Markle, R.J. [Advanced Micro Devices, Inc., Austin, TX (United States)

    1997-08-01

    Sandia National Laboratories has developed a system to monitor plasma processes for control of industrial applications. The system is designed to act as a fully automated, sand-alone process monitor during printed wiring board and semiconductor production runs. The monitor routinely performs data collection, analysis, process identification, and error detection/correction without the need for human intervention. The monitor can also be used in research mode to allow process engineers to gather additional information about plasma processes. The plasma monitor can perform real-time control of support systems known to influence plasma behavior. The monitor can also signal personnel to modify plasma parameters when the system is operating outside of desired specifications and requires human assistance. A notification protocol can be selected for conditions detected in the plasma process. The Plasma Process Monitor/Control System consists of a computer running software developed by Sandia National Laboratories, a commercially available spectrophotometer equipped with a charge-coupled device camera, an input/output device, and a fiber optic cable.

  4. Surface studies of plasma processed Nb samples

    Energy Technology Data Exchange (ETDEWEB)

    Tyagi, Puneet V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Doleans, Marc [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Hannah, Brian S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Afanador, Ralph [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Stewart, Stephen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Mammosser, John [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Howell, Matthew P [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Saunders, Jeffrey W [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Degraff, Brian D [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Kim, Sang-Ho [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)

    2015-01-01

    Contaminants present at top surface of superconducting radio frequency (SRF) cavities can act as field emitters and restrict the cavity accelerating gradient. A room temperature in-situ plasma processing technology for SRF cavities aiming to clean hydrocarbons from inner surface of cavities has been recently developed at the Spallation Neutron Source (SNS). Surface studies of the plasma-processed Nb samples by Secondary ion mass spectrometry (SIMS) and Scanning Kelvin Probe (SKP) showed that the NeO2 plasma processing is very effective to remove carbonaceous contaminants from top surface and improves the surface work function by 0.5 to 1.0 eV.

  5. Space plasma physics: I - Stationary processes

    Science.gov (United States)

    Hasegawa, Akira; Sato, Tetsuya

    1989-01-01

    The physics of stationary processes in space plasmas is examined theoretically in an introduction intended for graduate students. The approach involves the extensive use of numerical simulations. Chapters are devoted to fundamental principles, small-amplitude waves, and the stationary solar plasma system; typical measurement data and simulation results are presented graphically.

  6. Developments in Plasma Processes for Extractive Metallurgy

    Science.gov (United States)

    Gauvin, W. H.; Drouet, M. G.; Munz, R. J.

    1987-12-01

    With the recent availability of commercial plasma-generating devices capable of reliable performance at powers as high as 30 MW, the applications of plasma technology in high-temperature extractive metallurgy are rapidly increasing. Some of the more promising process developments are reviewed in this paper, as are newer reactor designs.

  7. The molecular structure of interfaces formed between plasma polymerized silica-like films and epoxy adhesives

    Science.gov (United States)

    Bengu, Basak

    The molecular structure of the interphase formed by curing a model adhesive system consisting of the diglycidyl ether of bisphenol-A (DGEBA) and dicyandiamide (DDA) against inorganic substrates, including mechanically polished aluminum, electrogalvanized steel (EGS) and plasma polymerized silica-like primer films, was determined using reflection--absorption infrared spectroscopy (RAIR) and X-ray photoelectron spectroscopy (XPS). RAIR analysis suggested that DGEBA/DDA mixtures created an interphase with a different molecular structure from the bulk of the adhesive when cured in contact with aluminum. The formation of this unique interphase was mainly due to interactions between DDA and the Al surface. XPS analysis indicated that aluminum ions exposed by heating the substrate surface were necessary for this interaction. DDA was found to adsorb onto the aluminum surface via the lone pair of electrons on the nitrogen atoms of the nitrile groups. A slight decrease in the nitrile stretching frequency indicated an additional back-bonding interaction between aluminum ions and the nitrile groups. Slight back donation of electrons from the metal to DDA resulted in a reduction product that led to the formation of the carbodiimide form of DDA. This specific reaction caused a decrease in the concentration of nitrile groups in the interphase and changed the network structure of the epoxy adhesive in the regions close to the oxide surface. The interaction of DDA with EGS surfaces followed a similar trend. However, the effects were much more pronounced with EGS and the path of the curing reaction and the network structure near the metal surface were strongly affected by EGS/DDA interactions. Two types of plasma polymerized silica-like films were prepared from hexamethyldisiloxane (HMDSO) monomer and oxygen by varying the gas compositions. One of the films was high and the other was low in hydroxyl content. XPS results showed that adjacent to the silica-like primer films, the

  8. The Plasma Chemistry of Polymer Surfaces

    CERN Document Server

    Friedrich, Jö

    2012-01-01

    This book illustrates plasma properties, polymer characteristics, surface specifics, and how to purposefully combine plasma and polymer chemistry. In so doing, it covers plasma polymerization, surface functionalization, etching, crosslinking, and deposition of monotype functional-group-bearing plasma polymers. It explains different techniques and plasma types, such as pressure-pulsed, remote, low-wattage plasmas and plasma polymerization in liquids. Finally, among the numerous applications discussed are plasmas for chemical synthesis, industrial processes or the modification of membranes and p

  9. Nanomechanical properties of advanced plasma polymerized coatings for mechanical data storage.

    Science.gov (United States)

    Tranchida, Davide; Pihan, Sascha A; Zhang, Yi; Schönherr, Holger; Berger, Rüdiger

    2011-04-07

    In this paper we report on the unprecedented deformation behavior of stratified ultrathin polymer films. The mechanical behavior of layered nanoscale films composed of 8-12 nm thin plasma polymerized hexamethyldisiloxane (ppHMDSO) films on a 70 nm thick film of polystyrene was unveiled by atomic force microscopy nanoindentation. In particular, we observed transitions from the deformation of a thin plate under point load to an elastic contact of a paraboloid of revolution, followed by an elastic-plastic contact for polystyrene and finally an elastic contact for silicon. The different deformation modes were identified on the basis of force-penetration data and atomic force microscopy images of residual indents. A clear threshold was observed for the onset of plastic deformation of the films at loads larger than 2 μN. The measured force curves are in agreement with an elastic and elastic-plastic contact mechanics model, taking the amount of deformation and the geometry of the layer that presumably contributed more to the overall deformation into account. This study shows that the complex deformation behavior of advanced soft matter systems with nanoscale dimensions can be successfully unraveled.

  10. Spectroscopic Study of Plasma Polymerized a-C:H Films Deposited by a Dielectric Barrier Discharge

    Directory of Open Access Journals (Sweden)

    Thejaswini Halethimmanahally Chandrashekaraiah

    2016-07-01

    Full Text Available Plasma polymerized a-C:H thin films have been deposited on Si (100 and aluminum coated glass substrates by a dielectric barrier discharge (DBD operated at medium pressure using C2Hm/Ar (m = 2, 4, 6 gas mixtures. The deposited films were characterized by Fourier transform infrared reflection absorption spectroscopy (FT-IRRAS, Raman spectroscopy, and ellipsometry. FT-IRRAS revealed the presence of sp3 and sp2 C–H stretching and C–H bending vibrations of bonds in the films. The presence of D and G bands was confirmed by Raman spectroscopy. Thin films obtained from C2H4/Ar and C2H6/Ar gas mixtures have ID/IG ratios of 0.45 and 0.3, respectively. The refractive indices were 2.8 and 3.1 for C2H4/Ar and C2H6/Ar films, respectively, at a photon energy of 2 eV.

  11. Fundamental Processes in Plasmas. Final report

    Energy Technology Data Exchange (ETDEWEB)

    O' Neil, Thomas M.; Driscoll, C. Fred

    2009-11-30

    This research focuses on fundamental processes in plasmas, and emphasizes problems for which precise experimental tests of theory can be obtained. Experiments are performed on non-neutral plasmas, utilizing three electron traps and one ion trap with a broad range of operating regimes and diagnostics. Theory is focused on fundamental plasma and fluid processes underlying collisional transport and fluid turbulence, using both analytic techniques and medium-scale numerical simulations. The simplicity of these systems allows a depth of understanding and a precision of comparison between theory and experiment which is rarely possible for neutral plasmas in complex geometry. The recent work has focused on three areas in basic plasma physics. First, experiments and theory have probed fundamental characteristics of plasma waves: from the low-amplitude thermal regime, to inviscid damping and fluid echoes, to cold fluid waves in cryogenic ion plasmas. Second, the wide-ranging effects of dissipative separatrices have been studied experimentally and theoretically, finding novel wave damping and coupling effects and important plasma transport effects. Finally, correlated systems have been investigated experimentally and theoretically: UCSD experients have now measured the Salpeter correlation enhancement, and theory work has characterized the 'guiding center atoms of antihydrogen created at CERN.

  12. Saturn Plasma Sources and Associated Transport Processes

    Science.gov (United States)

    Blanc, M.; Andrews, D. J.; Coates, A. J.; Hamilton, D. C.; Jackman, C. M.; Jia, X.; Kotova, A.; Morooka, M.; Smith, H. T.; Westlake, J. H.

    2015-10-01

    This article reviews the different sources of plasma for Saturn's magnetosphere, as they are known essentially from the scientific results of the Cassini-Huygens mission to Saturn and Titan. At low and medium energies, the main plasma source is the H2O cloud produced by the "geyser" activity of the small satellite Enceladus. Impact ionization of this cloud occurs to produce on the order of 100 kg/s of fresh plasma, a source which dominates all the other ones: Titan (which produces much less plasma than anticipated before the Cassini mission), the rings, the solar wind (a poorly known source due to the lack of quantitative knowledge of the degree of coupling between the solar wind and Saturn's magnetosphere), and the ionosphere. At higher energies, energetic particles are produced by energy diffusion and acceleration of lower energy plasma produced by the interchange instabilities induced by the rapid rotation of Saturn, and possibly, for the highest energy range, by contributions from the CRAND process acting inside Saturn's magnetosphere. Discussion of the transport and acceleration processes acting on these plasma sources shows the importance of rotation-induced radial transport and energization of the plasma, and also shows how much the unexpected planetary modulation of essentially all plasma parameters of Saturn's magnetosphere remains an unexplained mystery.

  13. Improvement of the water selectivity of ULTEM poly(ether imide) pervaporation films by an allylamine-plasma-polymerized layer

    OpenAIRE

    Kaba, Meriyam; Raklaoui, Nabil; Guimon, Marie Françoise; Mas, André

    2005-01-01

    International audience; The wettability and surface energy of extruded ULTEM poly(ether imide) films strongly increased (the water contact angle varied from 75 to 38° and the surface energy varied from 45.3 to 59.5 mJ m-2, respectively) with the deposition of an allylamine-plasma-polymerized layer and were characterized with X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy according to the experimental parameters. Pervaporation tests for dehydrating ...

  14. In-situ real time monitoring of the polymerization in gel-cast ceramic processes

    Energy Technology Data Exchange (ETDEWEB)

    Ahuja, S.; Dieckman, S.L.; Bostrom, G.A.; Waterfield, L.G.; Raptis, A.C. [Argonne National Lab., IL (United States); Omatete, O.O. [Oak Ridge National Lab., TN (United States)

    1996-08-01

    Gelcasting requires making a mixture of a slurry of ceramic powder in a solution of organic monomers and casting it in a mold. Gelcasting is different from injection molding in that it separates mold filling from setting during conversion of the ceramic slurry to a formed green part. In this work, NMR spectroscopy and imaging were used for in-situ monitoring of the gelation process and gelcasting of alumina. {sup 1}H NMR spectra and images are obtained during polymerization of a mixture of soluble reactive acrylamide monomers. Polymerization was initiated by adding an initiator and an accelerator to form long- chain, crosslinked polymers. Multidimensional NMR imaging was used for in-situ monitoring of the process and for verification of homogeneous polymerization. Comparison of the modeled intensities with acquired images shows a direction extraction of T{sub 1} data from the images.

  15. Plasma polymerization of ethylene in an atmospheric pressure-pulsed discharge

    Science.gov (United States)

    Donohoe, K.; Wydeven, T.

    1979-01-01

    The polymerization of ethylene in an atmospheric pressure-pulsed discharge has been studied. Partial pressures of ethylene up to 4 kN/sq m were used with helium as a diluent. Deposition rates (on glass slides) were the same throughout the discharge volume over a wide range of operating conditions. These rates were in the 1-2 A/sec range. The films were clear, soft, and showed good adhesion to the glass substrates. Oligomers large enough to visibly scatter 637.8-nm light were observed in the gas phase under all conditions in which film deposition occurred. The experimental results suggest that Brownian diffusion of these oligomers was the rate-limiting step in the film deposition process.

  16. Hydrogen Plasma Processing of Iron Ore

    Science.gov (United States)

    Sabat, Kali Charan; Murphy, Anthony B.

    2017-06-01

    Iron is currently produced by carbothermic reduction of oxide ores. This is a multiple-stage process that requires large-scale equipment and high capital investment, and produces large amounts of CO2. An alternative to carbothermic reduction is reduction using a hydrogen plasma, which comprises vibrationally excited molecular, atomic, and ionic states of hydrogen, all of which can reduce iron oxides, even at low temperatures. Besides the thermodynamic and kinetic advantages of a hydrogen plasma, the byproduct of the reaction is water, which does not pose any environmental problems. A review of the theory and practice of iron ore reduction using a hydrogen plasma is presented. The thermodynamic and kinetic aspects are considered, with molecular, atomic and ionic hydrogen considered separately. The importance of vibrationally excited hydrogen molecules in overcoming the activation energy barriers, and in transferring energy to the iron oxide, is emphasized. Both thermal and nonthermal plasmas are considered. The thermophysical properties of hydrogen and argon-hydrogen plasmas are discussed, and their influence on the constriction and flow in the of arc plasmas is considered. The published R&D on hydrogen plasma reduction of iron oxide is reviewed, with both the reduction of molten iron ore and in-flight reduction of iron ore particles being considered. Finally, the technical and economic feasibility of the process are discussed. It is shown that hydrogen plasma processing requires less energy than carbothermic reduction, mainly because pelletization, sintering, and cokemaking are not required. Moreover, the formation of the greenhouse gas CO2 as a byproduct is avoided. In-flight reduction has the potential for a throughput at least equivalent to the blast furnace process. It is concluded that hydrogen plasma reduction of iron ore is a potentially attractive alternative to standard methods.

  17. Hydrogen Plasma Processing of Iron Ore

    Science.gov (United States)

    Sabat, Kali Charan; Murphy, Anthony B.

    2017-03-01

    Iron is currently produced by carbothermic reduction of oxide ores. This is a multiple-stage process that requires large-scale equipment and high capital investment, and produces large amounts of CO2. An alternative to carbothermic reduction is reduction using a hydrogen plasma, which comprises vibrationally excited molecular, atomic, and ionic states of hydrogen, all of which can reduce iron oxides, even at low temperatures. Besides the thermodynamic and kinetic advantages of a hydrogen plasma, the byproduct of the reaction is water, which does not pose any environmental problems. A review of the theory and practice of iron ore reduction using a hydrogen plasma is presented. The thermodynamic and kinetic aspects are considered, with molecular, atomic and ionic hydrogen considered separately. The importance of vibrationally excited hydrogen molecules in overcoming the activation energy barriers, and in transferring energy to the iron oxide, is emphasized. Both thermal and nonthermal plasmas are considered. The thermophysical properties of hydrogen and argon-hydrogen plasmas are discussed, and their influence on the constriction and flow in the of arc plasmas is considered. The published R&D on hydrogen plasma reduction of iron oxide is reviewed, with both the reduction of molten iron ore and in-flight reduction of iron ore particles being considered. Finally, the technical and economic feasibility of the process are discussed. It is shown that hydrogen plasma processing requires less energy than carbothermic reduction, mainly because pelletization, sintering, and cokemaking are not required. Moreover, the formation of the greenhouse gas CO2 as a byproduct is avoided. In-flight reduction has the potential for a throughput at least equivalent to the blast furnace process. It is concluded that hydrogen plasma reduction of iron ore is a potentially attractive alternative to standard methods.

  18. Preparation of ion-exchange thin film using plasma processes. Plasma process wo mochiita ion kokansei usumaku no sakusei

    Energy Technology Data Exchange (ETDEWEB)

    Ogumi, Z.; Uchimoto, Y. (Kyoto University, Kyoto (Japan). Faculty of Engineering)

    1992-10-31

    The present report describes a study which aims at preparation of a new functional film by plasma polymerization. For this purpose, 4-vinylpyridine monomer is plasma-polymerized to obtain a thin film, which is quaternarized with 1-bromopropane to produce an anion exchange thin film, which is laminated on the surface of a cation-exchange film to make a mono-valent cation perm-selective film. In plasma-polymerization, the relations of polymerizing pressure, as parameter, to the deposition rate of the polymerizerd film and the characteristics of compound were clarified. In preparing the anion-exchange thin film, the preparation of uniform ultrathin films with no pinhole was attempted. For this purpose, the transference number of Cl[sup -] was measured so as to confirm that Cl[sup -] is uniformly distributed and fixed cation groups are distributed uniformly in the film. The perm-selective film exhibited a high mono-valent cation perm-selectivity while its film resistance was increased. This increase is found to be broken down to the resistance of the plasma-polymerization film layer and the resistance of the film interface. The latter arises from the implantation of nitrogen-cointaining species in the plasma onto the surface of the cation exchange film. 26 refs., 10 figs., 2 tabs.

  19. Investigation of glycerol polymerization in the clinker grinding process

    NARCIS (Netherlands)

    Parvulescu, A.N.; Rossi, M.; Della Pina, C.; Ciriminna, R.; Pagliaro, M.

    2011-01-01

    Concrete production is a large scale process that involves high energy consumption. In order to increase the sustainability of this process, the reduction of energy input is necessary. Bio-glycerol was demonstrated to be a highly efficient renewable-based additive in the grinding process for concret

  20. Gelation of a Reversible Markov Process of Polymerization

    Institute of Scientific and Technical Information of China (English)

    Dong Han; Yian-lin Han

    2003-01-01

    In this paper a reversible Markov process as a chemical polymers reaction of two types of monomers is defined. By analyzing the partition functions of the process we obtain three different distributions of the average molecular weight, depending on the value of strength of the fragmentation reaction, and prove that a gelation of the process will occur in the thermodynamic limit.

  1. In vitro cell culture, platelet adhesion tests and in vivo implant tests of plasma-polymerized para-xylene films

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Chia-Man [Department of Surgery, Taichung Veterans General Hospital, Taiwan, ROC (China); National Yang-Ming University, Taipei, Taiwan, ROC (China); Yeh, Chou-Ming, E-mail: cmchou4301@gmail.com [Taichung Hospital, Department of Health, Executive Yuan, Taiwan, ROC (China); Chung, Chi-Jen [Department of Dental Technology and Materials Science, Central Taiwan University of Science and Technology, Taiwan, ROC (China); He, Ju-Liang [Department of Materials Science and Engineering, Feng Chia University, Taiwan, ROC (China)

    2013-09-01

    Plasma-polymerized para-xylene (PPX) was developed in a previous study by adjusting the process parameters: pulse frequency of the power supply (ω{sub p}) and para-xylene monomer flow rate (f{sub p}). All the obtained PPX films exhibit an amorphous structure and present hydrophobicity (water contact angle ranging from 98.5° to 121.1°), higher film growth rate and good fibroblast cell proliferation. In this study, in vitro tests (fibroblast cell compatibility and platelet adhesion) and an in vivo animal study were performed by using PPX deposited industrial-grade silicone sheets (IGS) and compared with medical-grade silicone ones (MS), which were commonly manufactured into catheters or drainage tubes in clinical use. The results reveal that PPX deposited at high ω{sub p} or high f{sub p}, in comparison with MS, exhibit better cell proliferation and clearly shows less cell adhesion regardless of ω{sub p} and f{sub p}. PPX also exhibit a comparatively lower level of platelet adhesion than MS. In the animal study, PPX-coated IGS result in similar local tissue responses at 3, 7 and 28 days (short-term) and 84 days (long-term) after subcutaneous implantation the abdominal wall of rodents compared with respective responses to MS. These results suggest that PPX-coated industrial-grade silicone is one alternative to high cost medical-grade silicone.

  2. In vitro cell culture, platelet adhesion tests and in vivo implant tests of plasma-polymerized para-xylene films

    Science.gov (United States)

    Chou, Chia-Man; Yeh, Chou-Ming; Chung, Chi-Jen; He, Ju-Liang

    2013-09-01

    Plasma-polymerized para-xylene (PPX) was developed in a previous study by adjusting the process parameters: pulse frequency of the power supply (ωp) and para-xylene monomer flow rate (fp). All the obtained PPX films exhibit an amorphous structure and present hydrophobicity (water contact angle ranging from 98.5° to 121.1°), higher film growth rate and good fibroblast cell proliferation. In this study, in vitro tests (fibroblast cell compatibility and platelet adhesion) and an in vivo animal study were performed by using PPX deposited industrial-grade silicone sheets (IGS) and compared with medical-grade silicone ones (MS), which were commonly manufactured into catheters or drainage tubes in clinical use. The results reveal that PPX deposited at high ωp or high fp, in comparison with MS, exhibit better cell proliferation and clearly shows less cell adhesion regardless of ωp and fp. PPX also exhibit a comparatively lower level of platelet adhesion than MS. In the animal study, PPX-coated IGS result in similar local tissue responses at 3, 7 and 28 days (short-term) and 84 days (long-term) after subcutaneous implantation the abdominal wall of rodents compared with respective responses to MS. These results suggest that PPX-coated industrial-grade silicone is one alternative to high cost medical-grade silicone.

  3. Effect of light intensity and irradiation time on the polymerization process of a dental composite resin

    Directory of Open Access Journals (Sweden)

    Discacciati José Augusto César

    2004-01-01

    Full Text Available Polymerization shrinkage is a critical factor affecting the longevity and acceptability of dental composite resins. The aim of this work was to evaluate the effect of light intensity and irradiation time on the polymerization process of a photo cured dental composite resin by measuring the Vickers hardness number (VHN and the volumetric polymerization shrinkage. Samples were prepared using a dental manual light-curing unit. The samples were submitted to irradiation times of 5, 10, 20 and 40 s, using 200 and 400 mW.cm-2 light intensities. Vickers hardness number was obtained at four different moments after photoactivation (immediate, 1 h, 24 h and 168 h. After this, volumetric polymerization shrinkage values were obtained through a specific density method. The values were analyzed by ANOVA and Duncan's (p = 0.05. Results showed increase in hardness values from the immediate reading to 1 h and 24 h readings. After 24 h no changes were observed regardless the light intensities or activation times. The hardness values were always smaller for the 200 mW.cm-2 light intensity, except for the 40 s irradiation time. No significant differences were detected in volumetric polymerization shrinkage considering the light intensity (p = 0.539 and the activation time (p = 0.637 factors. In conclusion the polymerization of the material does not terminate immediately after photoactivation and the increase of irradiation time can compensate a lower light intensity. Different combinations between light intensity and irradiation time, i.e., different amounts of energy given to the system, have not affected the polymerization shrinkage.

  4. Plasma characterization studies for materials processing

    Energy Technology Data Exchange (ETDEWEB)

    Pfender, E.; Heberlein, J. [Univ. of Minnesota, Minneapolis, MN (United States)

    1995-12-31

    New applications for plasma processing of materials require a more detailed understanding of the fundamental processes occurring in the processing reactors. We have developed reactors offering specific advantages for materials processing, and we are using modeling and diagnostic techniques for the characterization of these reactors. The emphasis is in part set by the interest shown by industry pursuing specific plasma processing applications. In this paper we report on the modeling of radio frequency plasma reactors for use in materials synthesis, and on the characterization of the high rate diamond deposition process using liquid precursors. In the radio frequency plasma torch model, the influence of specific design changes such as the location of the excitation coil on the enthalpy flow distribution is investigated for oxygen and air as plasma gases. The diamond deposition with liquid precursors has identified the efficient mass transport in form of liquid droplets into the boundary layer as responsible for high growth, and the chemical properties of the liquid for the film morphology.

  5. Cluster processes in gases and plasmas

    CERN Document Server

    Smirnov, Boris M

    2009-01-01

    Boris M. Smirnov received his Ph.D. in physics from Leningrad State University in 1968. After working in different research positions, he finally accepted a post as head of one of the divisions of the Institute for High Temperatures at the Russian Academy of Sciences in Moscow in 1986. Professor Smirnov is the author and co-author of approximately 50 books as well as 400 research articles in plasma physics, atomic physics, and atomic clusters. He is Vice Chairman of the National Council for Low Temperature Plasma and Chairman ofa Section on Elementary Processes in Plasma. Professor Smirnov`s r

  6. Ultrasonic Plasma Spray--A New Plasma Spray Process

    Institute of Scientific and Technical Information of China (English)

    LU Zhi-qing; ZHANG Hua-tang; WEN Xiong-wei; LI Lu-ming

    2004-01-01

    The method of arc- ultrasonic is introduced into plasma spray process. The process of spray ZrO2-NiCoCr AlY thermal barrier coatings (TBCs) using air plasma spray (APS) process is studied. A exciting source which can be adjusted from audio frequency to several hundred thousand Hertz is designed successfully. The ultrasonic exciting source is coupled with conventional DC spraying power supply. A few ultrasonic frequencies are selected in the testing. Several parts of the coatings with the coupling arc- ultrasonic are compared with the coatings without it. The results show: with 50 kHz and 80 kHz ultrasound, the coating qualities are improved, whereas 30 kHz has an opposite effect.

  7. Atmospheric plasma processes for environmental applications

    OpenAIRE

    Shapoval, Volodymyr

    2012-01-01

    Plasma chemistry is a rapidly growing field which covers applications ranging from technological processing of materials, including biological tissues, to environmental remediation and energy production. The so called atmospheric plasma, produced by electric corona or dielectric barrier discharges in a gas at atmospheric pressure, is particularly attractive for the low costs and ease of operation and maintenance involved. The high concentrations of energetic and chemically active species (e.g...

  8. Atmospheric plasma processes for environmental applications

    OpenAIRE

    Shapoval, Volodymyr

    2012-01-01

    Plasma chemistry is a rapidly growing field which covers applications ranging from technological processing of materials, including biological tissues, to environmental remediation and energy production. The so called atmospheric plasma, produced by electric corona or dielectric barrier discharges in a gas at atmospheric pressure, is particularly attractive for the low costs and ease of operation and maintenance involved. The high concentrations of energetic and chemically active species (e.g...

  9. Plasma processing of superconducting radio frequency cavities

    Science.gov (United States)

    Upadhyay, Janardan

    The development of plasma processing technology of superconducting radio frequency (SRF) cavities not only provides a chemical free and less expensive processing method, but also opens up the possibility for controlled modification of the inner surfaces of the cavity for better superconducting properties. The research was focused on the transition of plasma etching from two dimensional flat surfaces to inner surfaces of three dimensional (3D) structures. The results could be applicable to a variety of inner surfaces of 3D structures other than SRF cavities. Understanding the Ar/Cl2 plasma etching mechanism is crucial for achieving the desired modification of Nb SRF cavities. In the process of developing plasma etching technology, an apparatus was built and a method was developed to plasma etch a single cell Pill Box cavity. The plasma characterization was done with the help of optical emission spectroscopy. The Nb etch rate at various points of this cavity was measured before processing the SRF cavity. Cylindrical ring-type samples of Nb placed on the inner surface of the outer wall were used to measure the dependence of the process parameters on plasma etching. The measured etch rate dependence on the pressure, rf power, dc bias, temperature, Cl2 concentration and diameter of the inner electrode was determined. The etch rate mechanism was studied by varying the temperature of the outer wall, the dc bias on the inner electrode and gas conditions. In a coaxial plasma reactor, uniform plasma etching along the cylindrical structure is a challenging task due to depletion of the active radicals along the gas flow direction. The dependence of etch rate uniformity along the cylindrical axis was determined as a function of process parameters. The formation of dc self-biases due to surface area asymmetry in this type of plasma and its variation on the pressure, rf power and gas composition was measured. Enhancing the surface area of the inner electrode to reduce the

  10. Polyethylene Oxide Films Polymerized by Radio Frequency Plasma-Enhanced Chemical Vapour Phase Deposition and Its Adsorption Behaviour of Platelet-Rich Plasma

    Science.gov (United States)

    Hu, Wen-Juan; Xie, Fen-Yan; Chen, Qiang; Weng, Jing

    2008-10-01

    We present polyethylene oxide (PEO) functional films polymerized by rf plasma-enhanced vapour chemical deposition (rf-PECVD) on p-Si (100) surface with precursor ethylene glycol dimethyl ether (EGDME) and diluted Ar in pulsed plasma mode. The influences of discharge parameters on the film properties and compounds are investigated. The film structure is analysed by Fourier transform infrared (FTIR) spectroscopy. The water contact angle measurement and atomic force microscope (AFM) are employed to examine the surface polarity and to detect surface morphology, respectively. It is concluded that the smaller duty cycle in pulsed plasma mode contributes to the rich C-O-C (EO) group on the surfaces. As an application, the adsorption behaviour of platelet-rich plasma on plasma polymerization films performed in-vitro is explored. The shapes of attached cells are studied in detail by an optic invert microscope, which clarifies that high-density C-O-C groups on surfaces are responsible for non-fouling adsorption behaviour of the PEO films.

  11. Polyethylene Oxide Films Polymerized by Radio Frequency Plasma-Enhanced Chemical Vapour Phase Deposition and Its Adsorption Behaviour of Platelet-Rich Plasma

    Institute of Scientific and Technical Information of China (English)

    HU Wen-Juan; XIE Fen-Yan; CHEN Qiang; WENG Jing

    2008-01-01

    We present polyethylene oxide (PEO) functional films polymerized by rf plasma-enhanced vapour chemical deposition (rf-PECVD) on p-Si (100) surface with precursor ethylene glycol dimethyl ether (EGDME) and diluted Ar in pulsed plasma mode. The influences of discharge parameters on the film properties and compounds are investigated. The film structure is analysed by Fourier transform infrared (FTIR) spectroscopy. The water contact angle measurement and atomic force microscope (AFM) are employed to examine the surface polarity and to detect surface morphology, respectively. It is concluded that the smaller duty cycle in pulsed plasma mode contributes to the rich C-O-C (EO) group on the surfaces. As an application, the adsorption behaviour of platelet-rich plasma on plasma polymerization films performed in-vitro is explored. The shapes of attached cells are studied in detail by an optic invert microscope, which clarifies that high-density C-O-C groups on surfaces are responsible for non-fouling adsorption behaviour of the PEO films.

  12. Terminology of Polymers and Polymerization Processes in Dispersed Systems (IUPAC Recommendations 2011

    Directory of Open Access Journals (Sweden)

    Rogošić, M.

    2012-07-01

    Full Text Available A large group of industrially important polymerization processes is carried out in dispersed systems. These processes differ with respect to their physical nature, mechanism of particle formation, particle morphology, size, charge, types of interparticle interactions, and many other aspects. Polymer dispersions, and polymers derived from polymerization in dispersed systems,are used in diverse areas such as paints, adhesives, microelectronics, medicine, cosmetics, biotechnology, and others. Frequently, the same names are used for different processes and products or different names are used for the same processes and products. The document contains a list of recommended terms and definitions necessary for the unambiguous description of processes, products, parameters, and characteristic features relevant to polymers in dispersed systems.

  13. Influence of the radio-frequency power on the physical and optical properties of plasma polymerized cyclohexane thin films

    Energy Technology Data Exchange (ETDEWEB)

    Manaa, C., E-mail: chadlia.el.manaa@gmail.com [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, UFR des Sciences d' Amiens, 33 rue Saint Leu, 80039 Amiens CEDEX 2 (France); Laboratoire des Matériaux Avancés et Phénomènes Quantiques, Université de Tunis El-Manar, Faculté des Sciences de Tunis, Campus universitaire El-Manar, 1068 Tunis (Tunisia); Lejeune, M. [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, UFR des Sciences d' Amiens, 33 rue Saint Leu, 80039 Amiens CEDEX 2 (France); Kouki, F. [Laboratoire des Matériaux Avancés et Phénomènes Quantiques, Université de Tunis El-Manar, Faculté des Sciences de Tunis, Campus universitaire El-Manar, 1068 Tunis (Tunisia); Durand-Drouhin, O. [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, UFR des Sciences d' Amiens, 33 rue Saint Leu, 80039 Amiens CEDEX 2 (France); Bouchriha, H. [Laboratoire des Matériaux Avancés et Phénomènes Quantiques, Université de Tunis El-Manar, Faculté des Sciences de Tunis, Campus universitaire El-Manar, 1068 Tunis (Tunisia); and others

    2014-06-02

    We investigate in the present study the effects of the radio-frequency plasma power on the opto-electronical properties of the polymeric amorphous hydrogenated carbon thin films deposited at room temperature and different radio-frequency powers by plasma-enhanced chemical vapor deposition method using cyclohexane as precursor. A combination of U.V.–Visible and infrared transmission measurements is applied to characterize the bonding and electronic properties of these films. Some film properties namely surface roughness, contact angle, surface energy, and optical properties are found to be significantly influenced by the radio-frequency power. The changes in these properties are analyzed within the microstructural modifications occurring during growth. - Highlights: • Effects of the radio-frequency power on the optoelectronic properties of thin films • Elaboration of plasma polymerized thin films using cyclohexane as precursor gas • The use of U.V.–Visible-infrared transmission, and optical gap • Study of the surface topography of the films by using Atomic Force microscopy • The use of a capacitively coupled plasma enhanced chemical vapor deposition method.

  14. Space plasma physics stationary processes

    CERN Document Server

    Hasegawa, Akira

    1989-01-01

    During the 30 years of space exploration, important discoveries in the near-earth environment such as the Van Allen belts, the plasmapause, the magnetotail and the bow shock, to name a few, have been made. Coupling between the solar wind and the magnetosphere and energy transfer processes between them are being identified. Space physics is clearly approaching a new era, where the emphasis is being shifted from discoveries to understanding. One way of identifying the new direction may be found in the recent contribution of atmospheric science and oceanography to the development of fluid dynamics. Hydrodynamics is a branch of classical physics in which important discoveries have been made in the era of Rayleigh, Taylor, Kelvin and Helmholtz. However, recent progress in global measurements using man-made satellites and in large scale computer simulations carried out by scientists in the fields of atmospheric science and oceanography have created new activities in hydrodynamics and produced important new discover...

  15. Microbial extracellular polymeric substances in marine biogeochemical processes

    Digital Repository Service at National Institute of Oceanography (India)

    Bhaskar, P.V.; Bhosle, N.B.

    for the fo ation and maintenance of microcolonies and oxygenfree con- ditions within the flocs that influence the spatial distribu- tion of different micro-organisms 68. Such niches in the micro-colonies become the hotspots for microbialaided organic... buried into the sediment. EPS in aggregation process In simple terms, aggregation is defined as a physical pro cess wherein micro particles collide and remain stuck to each other to form clumps of particles called aggrgates. These aggregates...

  16. Signal processing methods for MFE plasma diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Candy, J.V.; Casper, T.; Kane, R.

    1985-02-01

    The application of various signal processing methods to extract energy storage information from plasma diamagnetism sensors occurring during physics experiments on the Tandom Mirror Experiment-Upgrade (TMX-U) is discussed. We show how these processing techniques can be used to decrease the uncertainty in the corresponding sensor measurements. The algorithms suggested are implemented using SIG, an interactive signal processing package developed at LLNL.

  17. Assessment of the impact strength of the denture base resin polymerized by various processing techniques

    Directory of Open Access Journals (Sweden)

    Rajashree Jadhav

    2013-01-01

    Full Text Available Aim : To measure the impact strength of denture base resins polymerized using short and long curing cycles by water bath, pressure cooker and microwave techniques. Materials and Methods: For impact strength testing, 60 samples were made. The sample dimensions were 60 mm × 12 mm × 3 mm, as standardized by the American Standards for Testing and Materials (ASTM. A digital caliper was used to locate the midpoint of sample. The impact strength was measured in IZOD type of impact tester using CEAST Impact tester. The pendulum struck the sample and it broke. The energy required to break the sample was measured in Joules. Data were analyzed using Student′s " t" test. Results: There was statistically significant difference in the impact strength of denture base resins polymerized by long curing cycle and short curing cycle in each technique, with the long curing processing being the best. Conclusion: The polymerization technique plays an important role in the influence of impact strength in the denture base resin. This research demonstrates that the denture base resin polymerized by microwave processing technique possessed the highest impact strength.

  18. Nonthermal Radiation Processes in Interplanetary Plasmas

    Science.gov (United States)

    Chian, A. C. L.

    1990-11-01

    RESUMEN. En la interacci6n de haces de electrones energeticos con plasmas interplanetarios, se excitan ondas intensas de Langmuir debido a inestabilidad del haz de plasma. Las ondas Langmuir a su vez interaccio nan con fluctuaciones de densidad de baja frecuencia para producir radiaciones. Si la longitud de las ondas de Langmujr exceden las condicio nes del umbral, se puede efectuar la conversi5n de modo no lineal a on- das electromagneticas a traves de inestabilidades parametricas. As se puede excitar en un plasma inestabilidades parametricas electromagneticas impulsadas por ondas intensas de Langmuir: (1) inestabilidades de decaimiento/fusi5n electromagnetica impulsadas por una bomba de Lang- muir que viaja; (2) inestabilidades dobles electromagneticas de decai- miento/fusi5n impulsadas por dos bombas de Langrnuir directamente opues- tas; y (3) inestabilidades de dos corrientes oscilatorias electromagne- ticas impulsadas por dos bombas de Langmuir de corrientes contrarias. Se concluye que las inestabilidades parametricas electromagneticas in- ducidas por las ondas de Langmuir son las fuentes posibles de radiacio- nes no termicas en plasmas interplanetarios. ABSTRACT: Nonthermal radio emissions near the local electron plasma frequency have been detected in various regions of interplanetary plasmas: solar wind, upstream of planetary bow shock, and heliopause. Energetic electron beams accelerated by solar flares, planetary bow shocks, and the terminal shock of heliosphere provide the energy source for these radio emissions. Thus, it is expected that similar nonthermal radiation processes may be responsible for the generation of these radio emissions. As energetic electron beams interact with interplanetary plasmas, intense Langmuir waves are excited due to a beam-plasma instability. The Langmuir waves then interact with low-frequency density fluctuations to produce radiations near the local electron plasma frequency. If Langmuir waves are of sufficiently large

  19. Microwave heating and the acceleration of polymerization processes

    Science.gov (United States)

    Parodi, Fabrizio

    1999-12-01

    Microwave power irradiation of dielectrics is nowadays well recognized and extensively used as an exceptionally efficient and versatile heating technique. Besides this, it revealed since the early 1980s an unexpected, and still far from being elucidated, capacity of causing reaction and yield enhancements in a great variety of chemical processes. These phenomena are currently referred to as specific or nonthermal effects of microwaves. An overview of them and their interpretations given to date in achievements in the microwave processing of slow-curing thermosetting resins is also given. Tailored, quaternary cyanoalkoxyalkyl ammonium halide catalysts, further emphasizing the microwave enhancements of curing kinetics of isocyanate/epoxy and epoxy/anhydride resin systems, are here presented. Their catalytic efficiency under microwave irradiation, microwave heatability, and dielectric properties are discussed and interpreted by the aid of the result of semi-empirical quantum mechanics calculations and molecule dynamics simulations in vacuo. An ion-hopping conduction mechanism has been recognized as the dominant source of the microwave absorption capacities of these catalysts. Dipolar relaxation losses by their strongly dipolar cations, viceversa, would preferably be responsible for the peculiar catalytic effects displayed under microwave heating. This would occur through a well-focused, molecular microwave overheating of intermediate reactive anionic groupings, they could indirectly cause as the nearest neighbors of such negatively-charged molecular sites.

  20. Obtention of polymeric membrane fuel cells by low pressure plasma technique: Evaluation of total cell efficiency by function on the amount of platinum and the thickness of the deposited carbon support

    Science.gov (United States)

    Moreira, A. J.; Ordonez, N.; Mansano, R. D.

    2015-03-01

    This work aimed to obtain catalytic support over polymeric membrane building a fuel cell using low pressure plasma technique. For this, polymeric membranes were coated with carbon layer and platinum nanoparticles. The procedures were performed in separate steps in order to obtain firstly carbon layer and catalytic platinum nanoparticles. In the first step, the plasma processes were carried methane in order to obtain carbon layer over the polymeric membrane. At this stage, in order to obtain different thicknesses, were made several processes, reaching a thickness of 0.36μm to 1.4μm. The second step was to get the platinum nanoparticles on the carbon layer. For this, was used a platinum solid source and argon plasma. The study relied primarily on assessing the influence of the carbon layer on the performance of fuel cell. Compared with the commercial processes, it was observed that the results for fuel cells obtained by plasma have a better electric contact on three cell layers (catalyst - electrolyte - reagent). By electrochemical activity test was possible observe increase of reverse voltage of 0.8 volts to 1.24 volts according to increase the thickness of the carbon layer. The same behavior was also observed in the analysis of total efficiency, which was limited to 50% of maximum efficiency of commercial cell due the thickness of the carbon layer deposited during the preparation of this study, indicating a greater thickness with carbon it is possible to achieve the same efficiency of cells better than commercial.

  1. A necessary and sufficient condition for gelation of a reversible Markov process of polymerization

    CERN Document Server

    Han, D

    2003-01-01

    A reversible Markov process as a chemical polymerization model which permits the coagulation and fragmentation reactions is considered. We present a necessary and sufficient condition for the occurrence of a gelation in the process. We show that a gelation transition may or may not occur, depending on the value of the fragmentation strength, and, in the case that gelation takes place, a critical value for the occurrence of the gelation and the mass of the gel can be determined by close forms.

  2. Direct fabrication of nanoscale bio-adhesive patterns by electron beam surface modification of plasma polymerized poly ethylene oxide-like coatings.

    Science.gov (United States)

    Brétagnol, Frédéric; Sirghi, Lucel; Mornet, Stéphane; Sasaki, Takao; Gilliland, Douglas; Colpo, Pascal; Rossi, Francois

    2008-03-26

    In this study we present a method to produce nanostructured surfaces containing bio-adhesive features inside a non bio-adhesive matrix. The strategy is based on the combination of low pressure plasma polymerization and electron beam lithography processes and allows the fabrication of the structured materials in just two steps without using any solvents. In a first step, a thin protein-and-cell-repelling coating (∼10 nm) is obtained by plasma polymerization of Di-glyme. Then, in a second step, the bio-adhesive properties of the layer are tuned by monitoring the concentration of ether bonds of the film by irradiating it locally by different irradiation doses with an electron beam. Time-of-flight secondary ion mass spectroscopy and atomic force microscopy analysis have been used to characterize the produced surfaces. Experiments with a model protein (bovine serum albumin) on the patterned surfaces show preferential adhesion to the irradiated regions, indicating the potential of this simple technique for the development of highly compacted sensitive bio-sensing devices.

  3. Polymerization and processing of polymers in magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Benicewicz, B.C.; Smith, M.E.; Douglas, E.P. [Los Alamos National Lab., NM (United States)

    1997-04-01

    Liquid crystalline thermosets (LCT`s) have become recognized over the past few years as an important class of materials. Numerous reports from the authors laboratory and others have described their synthesis and phase behavior. In particular, the authors have described important effects due to the orientation of the rodlike molecules in a liquid crystalline phase. They have found that curing rates are enhanced compared to reaction in an isotropic phase, and that the glass transition of the fully cured material can be significantly higher than the final cure temperature. For structural applications, orientation of LCT`s will allow maximum improvement in mechanical properties. A few studies have described use of magnetic fields to orient LCT`s. However, no measurements were made of the tensile properties of materials processed in magnetic fields. The authors have conducted experiments which describe the tensile modulus dependence of an LCT over the complete range of magnetic field strengths from 0 to 18 Tesla. Their work has focused on the system composed of the diglycidyl ether of dihydroxy-{alpha}-methylstilbene (DGE-DHAMS) cured with sulfanilamide (SAA).

  4. A study of Corrosion Protection of Aluminum Metal by Tetraethoxysilane Plasma Polymerized Coatings-Influence of Aluminum Surface Pretreatments-

    Institute of Scientific and Technical Information of China (English)

    YoshihiroMomose; TatsuyaYabuki

    2004-01-01

    The corrosion-protective performance of plasma-polymerized (PP) coatings on pretreated aluminum substrates has been investigated by cathodic polarization curve measurement. The surface composition and electronic properties of the pretreated and PP film coated metal surfaces were also characterized by XPS and the temperature-programmed photoelectron emission (TPPE). A PP coating was prepared on the pretreated surfaces by plasma polymerization of a mixture of tetraethoxysilane (TEOS) monomer vapor and oxygen using a 13.56MHz radiofrequency generator. The polarization curve of PP film coated samples was measured in NaC1 aqueous solution. The weight loss rate calculated from the value of the corrosion current of the curve was used to estimate the protective performance of the PP film coated samples. Argon plasma treatment of the metal surface gave much better corrosion-protective performance than pretreatments such as oxidation by heating in air and diamond scratching. The XPS analysis indicated that the silicon oxide assigned to SiO2 was formed on the PP film coated surface. The TPPE analysis revealed that the electron emission characteristics for the metal surfaces pretreated only were strongly influenced by the pretreatments, while all the PP film coated samples exhibited nearly the same electron emission trend with a much decreased intensity.

  5. A study of Corrosion Protection of Aluminum Metal by Tetraethoxysilane Plasma Polymerized Coatings -Influence of Aluminum Surface Pretreatments-

    Institute of Scientific and Technical Information of China (English)

    Yoshihiro Momose; Tatsuya Yabuki

    2004-01-01

    The corrosion-protective performance of plasma-polymerized (PP) coatings on pretreated aluminum substrates has been investigated by cathodic polarization curve measurement. The surface composition and electronic properties of the pretreated and PP film coated metal surfaces were also characterized by XPS and the temperature-programmed photoelectron emission (TPPE). A PP coating was prepared on the pretreated surfaces by plasma polymerization of a mixture of tetraethoxysilane (TEOS) monomer vapor and oxygen using a 13.56MHz radiofrequency generator. The polarization curve of PP film coated samples was measured in NaCl aqueous solution. The weight loss rate calculated from the value of the corrosion current of the curve was used to estimate the protective performance of the PP film coated samples. Argon plasma treatment of the metal surface gave much better corrosion-protective performance than pretreatments such as oxidation by heating in air and diamond scratching. The XPS analysis indicated that the silicon oxide assigned to SiO2 was formed on the PP film coated surface. The TPPE analysis revealed that the electron emission characteristics for the metal surfaces pretreated only were strongly influenced by the pretreatments, while all the PP film coated samples exhibited nearly the same electron emission trend with a much decreased intensity.

  6. Methods for characterising microphysical processes in plasmas

    CERN Document Server

    de Wit, T Dudok; Furno, I; Sorriso-Valvo, L; Zimbardo, G

    2013-01-01

    Advanced spectral and statistical data analysis techniques have greatly contributed to shaping our understanding of microphysical processes in plasmas. We review some of the main techniques that allow for characterising fluctuation phenomena in geospace and in laboratory plasma observations. Special emphasis is given to the commonalities between different disciplines, which have witnessed the development of similar tools, often with differing terminologies. The review is phrased in terms of few important concepts: self-similarity, deviation from self-similarity (i.e. intermittency and coherent structures), wave-turbulence, and anomalous transport.

  7. Plasma Processes : Microwave plasma deposition of diamond like carbon coatings

    Indian Academy of Sciences (India)

    D S Patil; K Ramachandran; N Venkatramani; M Pandey; R D'Cunha

    2000-11-01

    The promising applications of the microwave plasmas have been appearing in the fields of chemical processes and semiconductor manufacturing. Applications include surface deposition of all types including diamond/diamond like carbon (DLC) coatings, etching of semiconductors, promotion of organic reactions, etching of polymers to improve bonding of the other materials etc. With a 2.45 GHz, 700 W, microwave induced plasma chemical vapor deposition (CVD) system set up in our laboratory we have deposited diamond like carbon coatings. The microwave plasma generation was effected using a wave guide single mode applicator. We have deposited DLC coatings on the substrates like stainless steel, Cu–Be, Cu and Si. The deposited coatings have been characterized by FTIR, Raman spectroscopy and ellipsometric techniques. The results show that we have achieved depositing ∼ 95% sp3 bonded carbon in the films. The films are uniform with golden yellow color. The films are found to be excellent insulators. The ellipsometric measurements of optical constant on silicon substrates indicate that the films are transparent above 900 nm.

  8. Plasma Processing of Lunar and Planetary Materials

    Science.gov (United States)

    Currier, R.; Blacic, J.

    2000-01-01

    Space exploration and colonization must include oxygen for propulsion and life support, as well as, structural materials for construction. To the extent possible, these should be derived from locally available planetary resources. We propose an extractive metallurgy and oxygen recovery process well-suited for resource utilization in space. Locally available minerals are placed in a radio frequency-generated hydrogen plasma. This is accomplished using a fluidized bed contacting device. Electromagnetic energy is coupled to the hydrogen gas forming a non-equilibrium plasma. The plasma produces the ideal reducing agent - atomic hydrogen - in direct and intimate contact with the solid particles. When using oxide minerals as a feed, atomic hydrogen extracts oxygen from the matrix through the formation of water. The water is subsequently split into oxygen and hydrogen (the hydrogen is then recycled back to the plasma reactor). The processed solids could then be refined to produce structural materials. A conceptual process flow diagram, which requires an initial charge of hydrogen, is given.

  9. STUDIES ON THE PERMEABILITY OF PVC /EBBA OVERLAPPED ULTRATHIN COMPOSITE MEMBRANES MODIFIED BY PLASMA- POLYMERIZATION WITH FLUOROCARBON MONOMERS

    Institute of Scientific and Technical Information of China (English)

    FU Xiucheng; JIN Xigao; Tisato KAJIYAMA

    1989-01-01

    The PVC/EBBA ultrathin composite membranes with thickness of about 100 nm were prepared by spreading the solution on water surface. The overlapped composite membrane showed a characteristic aggregation structure in which the polymer matrix exists as a three-dimensional spongy network and the liquid crystal domains were observedThe surface modification for the overlapped membranes was carried out by means of plasma-polymerization with the monomers of fluorocarbon compounds. Both Arrhenius plots of permeability coefficients for oxygen (-Po2) in the membrane samples before and after modification showed significant increase in the vicinity of the TKN of EBBA.

  10. Microwave plasma torch for processing hydrocarbon gases

    Directory of Open Access Journals (Sweden)

    Alex G. Zherlitsyn

    2016-03-01

    Full Text Available We designed and developed an ultrahigh-frequency (microwave plasma torch with a combined (nitrogen, methane plasma-forming environment, and microwave output of up to 2 kW, continuously. We demonstrate the possibility of using it in order to process natural and associated petroleum (APG gas into valuable products (hydrogen and carbon nanomaterial CNM with up to 70% efficiency. Based on the developed microwave plasma torch, we developed an apparatus capable of converting hydrocarbon feedstock at a capacity of 50 g/h yielding CNM and hydrogen of up to 70 vol. %. In its mobile small-tonnage version, this technology can be used on gas-condensate fields.

  11. Solar terrestrial coupling through space plasma processes

    Energy Technology Data Exchange (ETDEWEB)

    Birn, J. [and others

    2000-12-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project investigates plasma processes that govern the interaction between the solar wind, charged particles ejected from the sun, and the earth's magnetosphere, the region above the ionosphere governed by the terrestrial magnetic field. Primary regions of interest are the regions where different plasma populations interact with each other. These are regions of particularly dynamic plasma behavior, associated with magnetic flux and energy transfer and dynamic energy release. The investigations concerned charged particle transport and energization, and microscopic and macroscopic instabilities in the magnetosphere and adjacent regions. The approaches combined space data analysis with theory and computer simulations.

  12. Wettability control by laser texturing process generating localized gold nanoparticles on polymeric thin films.

    Science.gov (United States)

    Spano, F; Castellano, A; Massaro, A; Fragouli, D; Cingolani, R; Athanassiou, A

    2012-06-01

    In this work a new approach is introduced for surface properties control by laser texturing process. By UV laser irradiation, we are able to control the surface wettability of a chitosan polymeric film in which is introduced a chloroauric acid salt by immersion. Specifically the UV irradiation is responsible for the creation of gold nanoparticles at the irradiated surface of the polymeric film. This photolytic process allows us to localize and design accurately surface patterns and moreover to tune metallic particle size in the range of nanoscale. After the characterization of our gold textured surfaces by atomic force and scanning electron microscopies, we demonstrate the link between wettability surface properties and gold nanoparticles size. The experimental results indicate the influence of the laser intensity, the irradiation time and the polymer film thickness (by increasing the gold concentration) on the gold nanoparticle density and size.

  13. New Green Polymeric Composites Based on Hemp and Natural Rubber Processed by Electron Beam Irradiation

    OpenAIRE

    Maria-Daniela Stelescu; Elena Manaila; Gabriela Craciun; Maria Dumitrascu

    2014-01-01

    A new polymeric composite based on natural rubber reinforced with hemp has been processed by electron beam irradiation and characterized by several methods. The mechanical characteristics: gel fraction, crosslink density, water uptake, swelling parameters, and FTIR of natural rubber/hemp fiber composites have been investigated as a function of the hemp content and absorbed dose. Physical and mechanical properties present a significant improvement as a result of adding hemp fibres in blends. O...

  14. Emulsion polymerization of vinyl acetate: Safe optimization of a hazardous complex process

    Energy Technology Data Exchange (ETDEWEB)

    Copelli, S.; Derudi, M. [Politecnico di Milano, Dipartimento di Chimica, Materiali e Ingegneria Chimica ' G. Natta' , via Mancinelli 7, 20131 Milano (Italy); Sempere, J.; Serra, E. [IQS Universitat Ramon Llull, Departament d' Enginyeria Quimica, Via Augusta 390, 08017 Barcelona (Spain); Lunghi, A.; Pasturenzi, C. [Stazione Sperimentale per i Combustibili, viale A. De Gasperi 3, 20097 S. Donato M.se (Italy); Rota, R., E-mail: renato.rota@polimi.it [Politecnico di Milano, Dipartimento di Chimica, Materiali e Ingegneria Chimica ' G. Natta' , via Mancinelli 7, 20131 Milano (Italy)

    2011-08-15

    Highlights: {yields} Polymerizations can be hazardous complex processes difficult to be safely optimized. {yields} We used a topological criterion to safely optimize an emulsion homopolymerization. {yields} The procedure was validated through experiments on vinyl acetate homopolymerization. {yields} The reported approach can be generalized to other complex hazardous reacting systems. - Abstract: Fast and exothermic discontinuous emulsion polymerization processes are particularly difficult to optimize from both safety and productivity point of view because of the occurrence of side undesired reactions (e.g. chain transfer to monomer, backbiting, propagation of tertiary radicals, termination by disproportion, etc.) and the hazards of boiling phenomena and stable foam formation under atmospheric pressure. Moreover, the relevant number of loading, heating and cooling steps, required before starting the monomer addition (that is, the desired reaction), makes a strict product quality reproducibility very difficult to obtain. Under these operating conditions, it is necessary to employ a suitable combined theoretical and experimental procedure able to detect the optimum process dosing time at both the laboratory and the industrial scale. In this work, it is shown how to use the topological criterion theory together with proper adiabatic calorimeter and RC1 experimental data to safely optimize the synthesis of polyvinyl acetate through the radical emulsion polymerization of vinyl acetate by the means of an indirectly cooled isoperibolic semibatch reactor.

  15. Modeling of the polymerization process of the insulating layer of cable thermocouples

    Directory of Open Access Journals (Sweden)

    Olga Iashutina

    2017-01-01

    Full Text Available A mathematical model describing the main physical processes occurring during thermal processing of cable thermocouples (CT during their production is presented. The polymerization of the insulating layer is taken into account in the conditions of its intense heating. The developed mathematical model allows to carry out calculations of heat transfer processes under the conditions of substantial heterogeneity of cable thermocouple structure. The computational experiments carried out have established significant differences in the characteristics of heat transfer in CT in the presence of thermoelectrodes with differing thermophysical characteristics.

  16. Advanced Polymeric and Organic–Inorganic Membranes for Pressure-Driven Processes

    KAUST Repository

    Le, Ngoc Lieu

    2017-02-13

    The state-of-the-art of membranes for reverse osmosis, nanofiltration, and gas separation is shortly reviewed, taking in account the most representative examples currently in application. Emphasis is also done on recent developments of advanced polymeric and organic–inorganic materials for pressure-driven processes. Many of the more recent membranes are not only polymeric but also contain an inorganic phase. Tailoring innovative materials with organic and inorganic phases coexisting in a nanoscale with multifunctionalization is an appealing approach to control at the same time diffusivity and gas solubility. Other advanced materials that are now being considered for membrane development are organic or organic–inorganic self-assemblies, metal-organic frameworks, and different forms of carbon fillers.

  17. Multi input single output model predictive control of non-linear bio-polymerization process

    Energy Technology Data Exchange (ETDEWEB)

    Arumugasamy, Senthil Kumar; Ahmad, Z. [School of Chemical Engineering, Univerisiti Sains Malaysia, Engineering Campus, Seri Ampangan,14300 Nibong Tebal, Seberang Perai Selatan, Pulau Pinang (Malaysia)

    2015-05-15

    This paper focuses on Multi Input Single Output (MISO) Model Predictive Control of bio-polymerization process in which mechanistic model is developed and linked with the feedforward neural network model to obtain a hybrid model (Mechanistic-FANN) of lipase-catalyzed ring-opening polymerization of ε-caprolactone (ε-CL) for Poly (ε-caprolactone) production. In this research, state space model was used, in which the input to the model were the reactor temperatures and reactor impeller speeds and the output were the molecular weight of polymer (M{sub n}) and polymer polydispersity index. State space model for MISO created using System identification tool box of Matlab™. This state space model is used in MISO MPC. Model predictive control (MPC) has been applied to predict the molecular weight of the biopolymer and consequently control the molecular weight of biopolymer. The result shows that MPC is able to track reference trajectory and give optimum movement of manipulated variable.

  18. NafionTM膜表面改性用等离子体聚合方法提高膜的阳离子选择性%Surface Modification of Ion Exchange Membrane(NafionTM) The Enhancement of Cation Selectivity by Plasma Polymerization Process

    Institute of Scientific and Technical Information of China (English)

    曾蓉; 朱鹤孙; 庞志成; 弋峰

    2001-01-01

    An ultra-thin anionic exchange layer containing —NH2 and —CONH2 was deposited on the surface of NafionTM membrane. This layer was deposited from ethylene and ammonia using a glow-discharge plasma polymerization technique. The SEM, ATR(attenuated total reflection) spectra and XPS(X-ray photoelectron spectroscopy) showed that the resulted plasma polymers containing —NH2 and —CONH2 was about 0.5 μm thick. The proton perm-selectivity of plasma-modified NafionTM membrane was expressed by tCu, the transference number of the Cu2+ ion through the membrane which was determined by using NafionTM membrane as the separator in a typical two-compartment cell(0.25 mol/L CuCl2-0.5mol/L HCl|plasma-modified NafionTM membrane|1 mol/L HCl). Pretreatment of the NafionTM membrane by oxygen sputtering enhanced the adhesion of plasma polymer onto its surface. The plasma-treated membrane exhibited a high perm-selectivity and its resistance in 1 mol/L HCl was only a little bit higher than NafionTM membrane(<0.5 Ω*cm2).%采用辉光放电等离子体聚合方法, 以C2H4和NH3为单体, 在NafionTM膜表面沉积一层含氨基及酰氨基的类聚乙烯阴离子交换膜, 提高了NafionTM膜对阳离子的选择性, 同时不显著增加膜电阻. 由SEM确定该等离子体聚合膜厚约0.5 μm, 用红外光谱及X光电子能谱表征膜结构. 采用四电极法测量膜电阻, 膜对质子的选择性由Cu2+的迁移数tCu表征, 用二室隔膜装置(0.25 mol/L CuCl2-0.5 mol/L HCl|等离子体处理膜|1 mol/L HCl)测量tCu. O2等离子体预处理NafionTM膜有利于沉积膜在NafionTM膜上的沉积并与NafionTM膜紧密结合. 经改性后的NafionTM膜电阻值仍然很小, 在1 mol/L HCl溶液中电阻小于0.5 Ω*cm2.

  19. Ionic Liquid-Based Polymer Electrolytes via Surfactant-Assisted Polymerization at the Plasma-Liquid Interface.

    Science.gov (United States)

    Tran, Quoc Chinh; Bui, Van-Tien; Dao, Van-Duong; Lee, Joong-Kee; Choi, Ho-Suk

    2016-06-29

    We first report an innovative method, which we refer to as interfacial liquid plasma polymerization, to chemically cross-link ionic liquids (ILs). By this method, a series of all-solid state, free-standing polymer electrolytes is successfully fabricated where ILs are used as building blocks and ethylene oxide-based surfactants are employed as an assisted-cross-linking agent. The thickness of the films is controlled by the plasma exposure time or the ratio of surfactant to ILs. The chemical structure and properties of the polymer electrolyte are characterized by scanning electron microscopy (SEM), Fourier transformation infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) spectroscopy, X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), and electrochemical impedance spectroscopy (EIS). Importantly, the underlying polymerization mechanism of the cross-linked IL-based polymer electrolyte is studied to show that fluoroborate or halide anions of ILs together with the aid of a small amount of surfactants having ethylene oxide groups are necessary to form cross-linked network structures of the polymer electrolyte. The ionic conductivity of the obtained polymer electrolyte is 2.28 × 10(-3) S·cm(-1), which is a relatively high value for solid polymer electrolytes synthesized at room temperature. This study can serve as a cornerstone for developing all-solid state polymer electrolytes with promising properties for next-generation electrochemical devices.

  20. Modification of Polyester and Polyamide Fabrics by Different in Situ Plasma Polymerization Methods

    OpenAIRE

    ÖKTEM, T.; SEVENTEKİN, N.

    2000-01-01

    In order to increase the hydrophilicities, and therefore to impart soil resistance and to improve dyeability, poly(ethylene terephthalate) (PET) and polyamide (PAm) fabrics were treated in low-temperature plasmas. Five different modification types were applied. Fabrics were directly treated in acrylic acid, water, air, O2 and argon plasma. The plasma conditions (i.e., exposure time and discharge power) were changed to control the extent of plasma surface modification. Wettability, soil resist...

  1. Characterization of plasma-polymerized 4-vinyl pyridine with silver nanoparticies on poly(ethylene terephthalate) film for anti-microbial properties

    DEFF Research Database (Denmark)

    Jiang, J.; Winther-Jensen, Bjørn; Kjær, Erik Michael

    2006-01-01

    4-vinyl pyridine was polymerized on poly(ethylene terephthalate) (PET) film by using lower energy pulsed AC plasma under low pressure in Ar atmosphere. The plasma polymerized coating was characterized by ATR Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), field emission...... scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). Different thicknesses Of poly(4-vinyl pyridine) coating under different plasma polymerization conditions were studied. Silver nanoparticles with diameter around 50nm deposit were precipitated...... on the poly(4-vinyl pyridine) coating by UV irradiation in Silver nitride water solution, in order to enhance the anti-microbial properties. Different kinds of modified PET films were tested for anti-microbial properties against yeast (Debaryomyces hansenii) by using microbiological analyser mu-4200...

  2. Effect of a non-thermal, atmospheric-pressure, plasma brush on conversion of model self-etch adhesive formulations compared to conventional photo-polymerization

    Science.gov (United States)

    Chen, Mingsheng; Zhang, Ying; Yao, Xiaomei; Li, Hao; Yu, Qingsong; Wang, Yong

    2012-01-01

    Objective To determine the effectiveness and efficiency of non-thermal, atmospheric plasmas for inducing polymerization of model dental self-etch adhesives. Methods The monomer mixtures used were bis-[2-(methacryloyloxy)ethyl] phosphate (2MP) and 2-hydroxyethyl methacrylate (HEMA), with mass ratios of 70/30, 50/50 and 30/70. Water was added to the above formulations: 10–30 wt%. These monomer/water mixtures were treated steadily for 40 s under a non-thermal atmospheric plasma brush working at temperatures from 32° to 35°C. For comparison, photo-initiators were added to the above formulations for photo-polymerization studies, which were light-cured for 40 s. The degree of conversion (DC) of both the plasma- and light-cured samples was measured using FTIR spectroscopy with an attenuated total reflectance attachment. Results The non-thermal plasma brush was effective in inducing polymerization of the model self-etch adhesives. The presence of water did not negatively affect the DC of plasma-cured samples. Indeed, DC values slightly increased, with increasing water content in adhesives: from 58.3% to 68.7% when the water content increased from 10% to 30% in the adhesives with a 50/50 (2MP/HEMA) mass ratio. Conversion values of the plasma-cured groups were higher than those of light-cured samples with the same mass ratio and water content. Spectral differences between the plasma- and light-cured groups indicate subtle structural distinctions in the resultant polymer networks. Significance This research if the first to demonstrate that the non-thermal plasma brush induces polymerization of model adhesives under clinical settings by direct/indirect energy transfer. This device shows promise for polymerization of dental composite restorations having enhanced properties and performance. PMID:23018084

  3. Processing and storage effects on monomeric anthocyanins, percent polymeric color, and antioxidant capacity of processed blueberry products.

    Science.gov (United States)

    Brownmiller, C; Howard, L R; Prior, R L

    2008-06-01

    This study evaluated the effects of processing and 6 mo of storage on total monomeric anthocyanins, percent polymeric color, and antioxidant capacity of blueberries that were canned in syrup (CS), canned in water (CW), pureed, and juiced (clarified and nonclarified). Total monomeric anthocyanins, percent polymeric color, and oxygen radical absorbing capacity (ORAC) assay using fluorescein (ORAC(FL)) were determined postprocessing after 1 d, and 1, 3, and 6 mo of storage. Thermal processing resulted in marked losses in total anthocyanins (28% to 59%) and ORAC(FL) values (43% to 71%) in all products, with the greatest losses occurring in clarified juices and the least in nonclarified juices. Storage at 25 degrees C for 6 mo resulted in dramatic losses in total anthocyanins, ranging from 62% in berries CW to 85% in clarified juices. This coincided with marked increases in percent polymeric color values of these products over the 6-mo storage. The ORAC(FL) values showed little change during storage, indicating that the formation of polymers compensated for the loss of antioxidant capacity due to anthocyanin degradation. Methods are needed to retain anthocyanins in thermally processed blueberries.

  4. Processing and storage effects on monomeric anthocyanins, percent polymeric color, and antioxidant capacity of processed black raspberry products.

    Science.gov (United States)

    Hager, A; Howard, L R; Prior, R L; Brownmiller, C

    2008-08-01

    This study evaluated the effects of processing and 6 mo of storage on total monomeric anthocyanins, percent polymeric color, and antioxidant capacity of black raspberries that were individually quick-frozen (IQF), canned-in-syrup, canned-in-water, pureed, and juiced (clarified and nonclarified). Total monomeric anthocyanins, percent polymeric color, and ORAC(FL) were determined 1 d postprocessing and after 1, 3, and 6 mo of storage. Thermal processing resulted in marked losses in total anthocyanins ranging from 37% in puree to 69% to 73% in nonclarified and clarified juices, respectively, but only the juices showed substantial losses (38% to 41%) in ORAC(FL). Storage at 25 degrees C of all thermally processed products resulted in dramatic losses in total anthocyanins ranging from 49% in canned-in-syrup to 75% in clarified juices. This coincided with marked increases in percent polymeric color values of these products over the 6-mo storage. ORAC(FL) values showed little change during storage, indicating that the formation of polymers compensated for the loss of antioxidant capacity due to anthocyanin degradation. Total anthocyanins and ORACFL of IQF berries were well retained during long-term storage at -20 degrees C.

  5. Using artificial neural networks to model extrusion processes for the manufacturing of polymeric micro-tubes

    Science.gov (United States)

    Mekras, N.; Artemakis, I.

    2012-09-01

    In this paper a methodology and an application example are presented aiming to show how Artificial Neural Networks (ANNs) can be used to model manufacturing processes when mathematical models are missing or are not applicable e.g. due to the micro- & nano-scaling, due to non-conventional processes, etc. Besides the ANNs methodology, the results of a Software System developed will be presented, which was used to create ANNs models for micro & nano manufacturing processes. More specifically results of a specific application example will be presented, concerning the modeling of extrusion processes for polymeric micro-tubes. ANNs models are capable for modeling manufacturing processes as far as adequate experimental and/or historical data of processes' inputs & outputs are available for their training. The POLYTUBES ANNs models have been trained and tested with experimental data records of process' inputs and outputs concerning a micro-extrusion process of polymeric micro-tubes for several materials such as: COC, PC, PET, PETG, PP and PVDF. The main ANN model of the extrusion application example has 3 inputs and 9 outputs. The inputs are: tube's inner & outer diameters, and the material density. The model outputs are 9 process parameters, which correspond to the specific inputs e.g. process temperature, die inner & outer diameters, extrusion pressure, draw speed etc. The training of the ANN model was completed, when the errors for the model's outputs, which expressed the difference between the training target values and the ANNs outputs, were minimized to acceptable levels. After the training, the micro-extrusion ANN is capable to simulate the process and can be used to calculate model's outputs, which are the process parameters for any new set of inputs. By this way a satisfactory functional approximation of the whole process is achieved. This research work has been supported by the EU FP7 NMP project POLYTUBES.

  6. Development of non-thermal atmospheric pressure plasma system for surface modification of polymeric materials

    Science.gov (United States)

    Kasih, T. P.

    2017-04-01

    Non-thermal plasma has become one of the new technologies which are highly developed now days. This happens because the cold plasma using the principle of generated reactive gases that have the ability to modify the surface properties of a material or product without changing the original characteristics of the material. The purpose of this study is to develop a cold plasma system that operates at atmospheric pressure and investigates the effect of cold plasma treatment to change the surface characteristics of the polymer material polyethylene (PE) at various time conditions. We are successfully developing a non-thermal plasma system that can operate at atmospheric pressure and can be run with Helium or Argon gas. The characteristics of plasma will be discussed from the view of its electrical property, plasma discharge regime andoperation temperature. Experiment results on plasma treatment on PE material shows the changes of surface properties of originally hydrophobic material PE becomes hydrophilic by only few seconds of plasma treatment and level of hydrophilicity become greater with increasing duration of plasma treatment. Confirmation of this is shown by the measurement of contact angle of droplets of water on the surface of PE are getting smaller.

  7. Preparation of nitrogen doped silicon oxides thin films by plasma polymerization of 3-aminopropyltriethoxylsilane using atmospheric pressure plasma jet

    Science.gov (United States)

    Lin, Yu-Chun; Wang, Meng-Jiy

    2016-01-01

    Surface modification techniques have been applied in various applications including self-cleaning surface, antibacterial filter, and biomaterials. In this study we employed the atmospheric pressure plasma jet (APPJ) deposition, a dry process for surface modification, to deposit 3-aminopropyltriethoxylsilane (APTES) on stainless steel (SS) on the purposes of simultaneously incorporating SiOx and nitrogen containing functionalities for the modulation of biofunctionality. The APPJ deposition allowed to form a thin layer of APTES with linear growth rate by controlling the deposition time. In addition, the surface chemical and physical properties, such as surface chemical composition, wettability, film thickness, and interactions with mammalian cells were evaluated by using different analytical methods. The results showed that the surface wettability was improved significantly due to the APTES deposition along with the increase of the incorporated nitrogen content. Moreover, the viability of L-929 fibroblasts was clearly promoted on the APTES deposited SS, which is most probably due to the thicker deposited films and higher density of nitrogen-containing functional groups. The outcomes of this research showed great potential to apply on metallic substrates in real time for biomedical related applications.

  8. Polymer coatings on plane and spherical surfaces obtained by plasma polymerization from trans-2-butene and hydrogen mixture; Depots de polymere sur surfaces planes et spheriques obtenus par polymerisation plasma a partir d`un melange de trans-2-butene et d`hydrogene

    Energy Technology Data Exchange (ETDEWEB)

    Benardais, A

    1997-10-21

    This study of a low frequency plasma polymerization process was undertaken to be used in manufacturing of targets used in laser-matter interaction experiments. In this system, whether the sample is placed in the discharge or outside of the discharge, hydrocarbon coatings from a gaseous mixture of hydrogen and trans-2-butene are obtain. This study consists of two parts. We first dealt with the understanding of plasma polymerization mechanisms in the reactor which resulted in a better process optimization. The study of gas flow in the reactor allowed us to determine the species repartition in the vessel. With experiments performed on the electrical behavior in the reactor we were able to define the discharge type. Then, species present in the plasma were analysed by emission spectroscopy and mass spectrometry and then reaction mechanisms were proposed. Attention was paid to the role of hydrogen which in fact acted as a reagent like trans-2-butene. We also worked on the process optimization in order to obtain a good working point which produces coatings which are as transparent as possible, contain only carbon and hydrogen (and the least amount of oxygen), have a smooth surface finish (mean square root of roughness < 50 nm) and retain their qualities overtime. After the reactor characterization, the study of the effects of different parameters (inner or post-discharge coatings, pressure, total gas flow, composition of the mixture of trans-2-butene and hydrogen, power, frequency, interelectrode distance) on deposition rate, roughness and chemical composition of coatings led to the finding of optimal deposition conditions. (author) 103 refs.

  9. Melt-processed polymeric cellular dosage forms for immediate drug release.

    Science.gov (United States)

    Blaesi, Aron H; Saka, Nannaji

    2015-12-28

    The present immediate-release solid dosage forms, such as the oral tablets and capsules, comprise granular matrices. While effective in releasing the drug rapidly, they are fraught with difficulties inherent in processing particulate matter. By contrast, liquid-based processes would be far more predictable; but the standard cast microstructures are unsuited for immediate-release because they resist fluid percolation and penetration. In this article, we introduce cellular dosage forms that can be readily prepared from polymeric melts by incorporating the nucleation, growth, and coalescence of microscopic gas bubbles in a molding process. We show that the cell topology and formulation of such cellular structures can be engineered to reduce the length-scale of the mass-transfer step, which determines the time of drug release, from as large as the dosage form itself to as small as the thickness of the cell wall. This allows the cellular dosage forms to achieve drug release rates over an order of magnitude faster compared with those of cast matrices, spanning the entire spectrum of immediate-release and beyond. The melt-processed polymeric cellular dosage forms enable predictive design of immediate-release solid dosage forms by tailoring microstructures, and could be manufactured efficiently in a single step.

  10. Surface modification of blood-contacting biomaterials by plasma-polymerized superhydrophobic films using hexamethyldisiloxane and tetrafluoromethane as precursors

    Energy Technology Data Exchange (ETDEWEB)

    Hsiao, Chaio-Ru [Department of Materials Science and Engineering, Feng Chia University, No. 100, Wenhwa Rd., Seatwen District, Taichung City 40724, Taiwan (China); Lin, Cheng-Wei [Department of Dental Technology and Materials Science, Central Taiwan University of Science and Technology, No. 666, Buzih Rd., Beitun District, Taichung City 40601, Taiwan (China); Chou, Chia-Man, E-mail: cmchou@vghtc.gov.tw [Department of Surgery, Taichung Veterans General Hospital, No. 1650, Sec. 4, Taiwan Boulevard, Seatwen District, Taichung City 40705, Taiwan (China); Department of Medicine, National Yang-Ming University, No. 155, Sec. 2, Linong Street, Beitou District, Taipei City 11221, Taiwan (China); Chung, Chi-Jen, E-mail: cjchung@seed.net.tw [Department of Dental Technology and Materials Science, Central Taiwan University of Science and Technology, No. 666, Buzih Rd., Beitun District, Taichung City 40601, Taiwan (China); He, Ju-Liang [Department of Materials Science and Engineering, Feng Chia University, No. 100, Wenhwa Rd., Seatwen District, Taichung City 40724, Taiwan (China)

    2015-08-15

    Highlights: • Biomaterials modified by nanoparticle-containing plasma polymerized films. • A superhydrophoic film was obtained, and the properties of the coating were examined. • In vitro blood compatibility tests revealed neither platelet adhesion nor fibrinogen adsorption. • Surface modification technology of medical devices: non-cytotoxic and no blood clot formation. - Abstract: This paper proposes a plasma polymerization system that can be used to modify the surface of the widely used biomaterial, polyurethane (PU), by employing low-cost hexamethyldisiloxane (HMDSO) and tetrafluoromethane (CF{sub 4}) as precursors; this system features a pulsed-dc power supply. Plasma-polymerized HMDSO/CF{sub 4} (pp-HC) with coexisting micro- and nanoscale morphology was obtained as a superhydrophobic coating material by controlling the HMDSO/CF{sub 4} (f{sub H}) monomer flow ratio. The developed surface modification technology can be applied to medical devices, because it is non-cytotoxic and has favorable hemocompatibility, and no blood clots form when the device surface direct contacts. Experimental results reveal that the obtained pp-HC films contained SiO{sub x} nanoparticles randomly dispersed on the micron-scale three-dimensional network film surface. The −CF functional group, −CF{sub 2} bonding, and SiO{sub x} were detected on the film surface. The maximal water contact angle of the pp-HC coating was 161.2°, apparently attributable to the synergistic effect of the coexisting micro- and nanoscale surface morphology featuring a low surface-energy layer. The superhydrophobic and antifouling characteristics of the coating were retained even after it was rubbed 20 times with a steel wool tester. Results of in vitro cytotoxicity, fibrinogen adsorption, and platelet adhesion tests revealed favorable myoblast cell proliferation and the virtual absence of fibrinogen adsorption and platelet adhesion on the pp-HC coated specimens. These quantitative findings imply

  11. Polymeric Nanocomposite Membranes for Next Generation Pervaporation Process: Strategies, Challenges and Future Prospects

    Directory of Open Access Journals (Sweden)

    Sagar Roy

    2017-09-01

    Full Text Available Pervaporation (PV has been considered as one of the most active and promising areas in membrane technologies in separating close boiling or azeotropic liquid mixtures, heat sensitive biomaterials, water or organics from its mixtures that are indispensable constituents for various important chemical and bio-separations. In the PV process, the membrane plays the most pivotal role and is of paramount importance in governing the overall efficiency. This article evaluates and collaborates the current research towards the development of next generation nanomaterials (NMs and embedded polymeric membranes with regard to its synthesis, fabrication and application strategies, challenges and future prospects.

  12. Crystal structure of polymeric carbon nitride and the determination of its process-temperature-induced modifications

    Science.gov (United States)

    Tyborski, T.; Merschjann, C.; Orthmann, S.; Yang, F.; Lux-Steiner, M.-Ch; Schedel-Niedrig, Th

    2013-10-01

    Based on the arrangement of two-dimensional ‘melon’, we construct a unit cell for polymeric carbon nitride (PCN) synthesized via thermal polycondensation, whose theoretical diffraction powder pattern includes all major features measured in x-ray diffraction. With the help of this unit cell, we describe the process-temperature-induced crystallographic changes in PCN that occur within a temperature interval between 510 and 610 °C. We also discuss further potential modifications of the unit cell for PCN. It is found that both triazine- and heptazine-based g-C3N4 can only account for minor phases within the investigated synthesis products.

  13. Real-Time Fault Classification for Plasma Processes

    OpenAIRE

    Yang, Ryan; Chen, Rongshun

    2011-01-01

    Plasma process tools, which usually cost several millions of US dollars, are often used in the semiconductor fabrication etching process. If the plasma process is halted due to some process fault, the productivity will be reduced and the cost will increase. In order to maximize the product/wafer yield and tool productivity, a timely and effective fault process detection is required in a plasma reactor. The classification of fault events can help the users to quickly identify fault processes, ...

  14. Preparation and characterization of ethylenediamine and cysteamine plasma polymerized films on piezoelectric quartz crystal surfaces for a biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Mutlu, Selma [Department of Chemical Engineering, Hacettepe University, Beytepe Campus, 06800 Ankara (Turkey)], E-mail: smselma@hacettepe.edu.tr; Coekeliler, Dilek [Plasma Aided Bioengineering and Biotechnology Research Group(PABB), Faculty of Engineering, Hacettepe University, Beytepe Campus, 06800 Ankara (Turkey); Shard, Alex [Department of Engineering Materials, The University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, S1 3JD (United Kingdom); Goktas, Hilal [Physics Department, Canakkale Onsekiz Mart University, 17100 Canakkale (Turkey); Ozansoy, Berna [Department of Chemical Engineering, Hacettepe University, Beytepe Campus, 06800 Ankara (Turkey); Mutlu, Mehmet [Plasma Aided Bioengineering and Biotechnology Research Group(PABB), Faculty of Engineering, Hacettepe University, Beytepe Campus, 06800 Ankara (Turkey)

    2008-01-30

    This paper describes a method for the modification of quartz crystal surfaces to be used as a transducer in biosensors that allow recognition and quantification of certain biomolecules (antibodies, enzymes, proteins, etc). Quartz crystal sensors were modified by a plasma based electron beam generator in order to detect the level of the toxin histamine within biological liquids (blood, serum) and food (wine, cheese, fish etc.). Cysteamine and ethylenediamine were used as precursors in the plasma. After each modification step, the layers on the quartz crystal were characterized by frequency measurements. Modified surfaces were also characterized by contact angle, X-ray photoelectron spectroscopy and atomic force microscopy to determine the physical and chemical characteristics of the surfaces after each modification. Finally, the performance of the sensors were tested by the response to histamine via frequency shifts. The frequency shifts of the sensors prepared by plasma polymerization of ethylenediamine and cysteamine were approximately 3230 Hz and 5630 Hz, respectively, whereas the frequency change of the unmodified crystal surface was around 575 Hz.

  15. Chemical vapor deposition graphene transfer process to a polymeric substrate assisted by a spin coater

    Science.gov (United States)

    Kessler, Felipe; da Rocha, Caique O. C.; Medeiros, Gabriela S.; Fechine, Guilhermino J. M.

    2016-03-01

    A new method to transfer chemical vapor deposition graphene to polymeric substrates is demonstrated here, it is called direct dry transfer assisted by a spin coater (DDT-SC). Compared to the conventional method DDT, the improvement of the contact between graphene-polymer due to a very thin polymeric film deposited by spin coater before the transfer process prevented air bubbles and/or moisture and avoided molecular expansion on the graphene-polymer interface. An acrylonitrile-butadiene-styrene copolymer, a high impact polystyrene, polybutadiene adipate-co-terephthalate, polylactide acid, and a styrene-butadiene-styrene copolymer are the polymers used for the transfers since they did not work very well by using the DDT process. Raman spectroscopy and optical microscopy were used to identify, to quantify, and to qualify graphene transferred to the polymer substrates. The quantity of graphene transferred was substantially increased for all polymers by using the DDT-SC method when compared with the DDT standard method. After the transfer, the intensity of the D band remained low, indicating low defect density and good quality of the transfer. The DDT-SC transfer process expands the number of graphene applications since the polymer substrate candidates are increased.

  16. Manufacturing processes for polymeric micro and nanoparticles and their biomedical applications

    Directory of Open Access Journals (Sweden)

    Ana Letícia Braz

    2017-01-01

    Full Text Available Polymeric materials have been widely investigated for biomedical applications as micro- and nanoparticles, for drug delivery, tissue engineering and regenerative medicine. The manufacturing processes employed utilise an array of different techniques, including electrospray, atomisation, emulsion cross-linking, precipitation, microfluidics and 3D printing amongst others. Technique selection and process parameters enable the production of a wide range of particles with different morphologies, porosities and size distributions. Currently, researchers are investigating varying the parameters to enhance particle profiles and morphologies including for example, ultrasound waves, particle surface charge and chemical attraction between the materials interfaces. Furthermore, the size of the particles produced can strongly influence the specific biomedical applications applied. Moreover, particles can be made with multilayer features enabling loading of multiple compounds into the particles, and can be used to prevent interaction between different drugs. Micro and nanoparticles can also exhibit different levels of porosity between core and shell, which can further influence cell attachment and elimination from the body. This review compares the essential features of the above manufacturing processes highlighted for polymeric micro and nanoparticles and highlights some of the applications related to their morphology and size.

  17. Radiant-and-plasma technology for coal processing

    OpenAIRE

    Vladimir Messerle; Alexander Ustimenko

    2012-01-01

    Radiant-and-plasma technology for coal processing is presented in the article. Thermodynamic computation and experiments on plasma processing of bituminous coal preliminary electron-beam activated were fulfilled in comparison with plasma processing of the coal. Positive influence of the preliminary electron-beam activation of coal on synthesis gas yield was found. Experiments were carried out in the plasma gasifier of 100 kW power. As a result of the measurements of material and heat balance ...

  18. Amelioration de l'adhesion de revetements organiques deposes par plasma froid sur polymeres pour applications biomedicales

    Science.gov (United States)

    Sbai, Marouan

    Plasma surface modification is commonly used in biomedical field, for example to enhance cell adhesion and growth surrounding the stent covers without affecting its bulk properties. Plasma polymer (PP) deposition used to create thin films rich in functional groups, e.g. primary amines, known to enhance the cellular response and allow grafting of biomolecules especially on stent grafts. Thin film adhesion to stent polymeric cover should be considered especially as they will evolve in a biological environment. The aim of this project is to evaluate the adhesion of PP on polytetrafluoroethylene (PTFE) and polyethyleneterephthalate (PET). Thereafter, an ammonia plasma treatment on PTFE is performed prior to deposition of PP to optimize the PP/PTFE adhesion. PP studied here (referred to as "LP") is prepared from a mixture of ethylene (C2H4) and ammonia (NH3). It is deposited on two supports, PET and PTFE. The interfacial adhesion between the LP coating and the substrate was evaluated by "Peel-test 180 °" according to ASTM F1842. Staining of the surface after peel test followed by an image analysis was performed to determine the percentage of removed coating. Adhesion optimization is done by varying operating plasma parameters such as power, pressure and pretreatment time. Chemical analyses and wettability of LP and pretreated surfaces in dry and wet conditions are characterized by XPS and contact angle measurements, respectively. The adhesion of LP/PET was excellent in a dry environment (water, respectively). However, 56% to 75% of the LP is removed from virgin PTFE in a dry and wet environment, respectively; percentages can be substantially reduced by plasma pretreatment (0% and 8+/-3% in air and 30min in deionized water). Almost no delamination was observed with NH3 plasma pretreatment at 15s, 100 mTorr and 50W. N2 plasma pretreatment, for comparison, proves much less effective. The LP/PTFE adhesion is considerably improved by plasma pretreatment compared to

  19. Surface modification of blood-contacting biomaterials by plasma-polymerized superhydrophobic films using hexamethyldisiloxane and tetrafluoromethane as precursors

    Science.gov (United States)

    Hsiao, Chaio-Ru; Lin, Cheng-Wei; Chou, Chia-Man; Chung, Chi-Jen; He, Ju-Liang

    2015-08-01

    This paper proposes a plasma polymerization system that can be used to modify the surface of the widely used biomaterial, polyurethane (PU), by employing low-cost hexamethyldisiloxane (HMDSO) and tetrafluoromethane (CF4) as precursors; this system features a pulsed-dc power supply. Plasma-polymerized HMDSO/CF4 (pp-HC) with coexisting micro- and nanoscale morphology was obtained as a superhydrophobic coating material by controlling the HMDSO/CF4 (fH) monomer flow ratio. The developed surface modification technology can be applied to medical devices, because it is non-cytotoxic and has favorable hemocompatibility, and no blood clots form when the device surface direct contacts. Experimental results reveal that the obtained pp-HC films contained SiOx nanoparticles randomly dispersed on the micron-scale three-dimensional network film surface. The sbnd CF functional group, sbnd CF2 bonding, and SiOx were detected on the film surface. The maximal water contact angle of the pp-HC coating was 161.2°, apparently attributable to the synergistic effect of the coexisting micro- and nanoscale surface morphology featuring a low surface-energy layer. The superhydrophobic and antifouling characteristics of the coating were retained even after it was rubbed 20 times with a steel wool tester. Results of in vitro cytotoxicity, fibrinogen adsorption, and platelet adhesion tests revealed favorable myoblast cell proliferation and the virtual absence of fibrinogen adsorption and platelet adhesion on the pp-HC coated specimens. These quantitative findings imply that the pp-HC coating can potentially prevent the formation of thrombi and provide an alternative means of modifying the surfaces of blood-contacting biomaterials.

  20. Surface functionalization of macroporous polymeric materials by treatment with air low temperature plasma.

    Science.gov (United States)

    Molina, R; Sole, I; Vílchez, A; Bertran, E; Solans, C; Esquena, J

    2013-04-01

    Polystyrene/divinylbenzene (PS-DVB) macroporous monoliths obtained using highly concentrated emulsions as templates show a superhydrophobic behaviour, restricting their potential technological applications, especially those related to adhesion and wetting. Air plasma treatments were carried out in order to modulate wetting properties, modifying the surface chemical composition of macroporous polystyrene/divinylbenzene materials. The superhydrophobic behaviour was rapidly suppressed by air plasma treatment, greatly reducing the water contact angle, from approximately 150 degrees to approximately 90 degrees, in only 10 seconds of treatment. The new surface chemical groups, promoted by plasma active species, were characterized by surface analysis techniques with different depth penetration specificity (contact angle, XPS, FTIR and SEM). Results demonstrated that very short treatment times produced different chemical functionalities, mainly C-O, C=O, O-C=O and C-N, which provide the materials with predominantly acidic surface properties. However, plasma active species did not penetrate deeply through the interconnected pores of the material. FTIR analysis evidenced that the new hydrophilic surface groups promoted by plasma active species are in a negligibly concentration compared to bulk chemical groups, and are located in a very thin surface region on the PS-DVB monolith surface (significantly below 2 microm). XPS analysis of treated monoliths revealed a progressive increase of oxygen and nitrogen content as a function of plasma treatment time. However, oxidation of the PS-DVB monoliths surface prevails over the incorporation of nitrogen atoms. Finally, SEM studies indicated that the morphology of the plasma treated PS-DVB does not significantly change even for the longest air plasma treatment time studied (120 s).

  1. Emulsion polymerization of vinyl acetate: safe optimization of a hazardous complex process.

    Science.gov (United States)

    Copelli, S; Derudi, M; Sempere, J; Serra, E; Lunghi, A; Pasturenzi, C; Rota, R

    2011-08-15

    Fast and exothermic discontinuous emulsion polymerization processes are particularly difficult to optimize from both safety and productivity point of view because of the occurrence of side undesired reactions (e.g. chain transfer to monomer, backbiting, propagation of tertiary radicals, termination by disproportion, etc.) and the hazards of boiling phenomena and stable foam formation under atmospheric pressure. Moreover, the relevant number of loading, heating and cooling steps, required before starting the monomer addition (that is, the desired reaction), makes a strict product quality reproducibility very difficult to obtain. Under these operating conditions, it is necessary to employ a suitable combined theoretical and experimental procedure able to detect the optimum process dosing time at both the laboratory and the industrial scale. In this work, it is shown how to use the topological criterion theory together with proper adiabatic calorimeter and RC1 experimental data to safely optimize the synthesis of polyvinyl acetate through the radical emulsion polymerization of vinyl acetate by the means of an indirectly cooled isoperibolic semibatch reactor.

  2. Effect of leaching residual methyl methacrylate concentrations on in vitro cytotoxicity of heat polymerized denture base acrylic resin processed with different polymerization cycles

    Directory of Open Access Journals (Sweden)

    Canan Bural

    2011-08-01

    the polymerization process for at least 30 min and water storage of the heat-polymerized denture bases for at least 1 to 2 days before denture delivery is clinically recommended for minimizing the residual MMA and possible cytotoxic effects.

  3. Process Chain for the Manufacture of Polymeric Tubular Micro-Components and “POLYTUBES Micro-Factory” Concept

    DEFF Research Database (Denmark)

    Qin, Yi; Perzon, Erik; Chronakis, Ioannis S.;

    The paper presents a process chain for the shaping of poly-meric tubular micro-components for the volume production as well as presents a concept for the integration of the developed processes and modular machines onto a platform to form a "POLYTUBES Micro-Factory", being resulting from the Europ......The paper presents a process chain for the shaping of poly-meric tubular micro-components for the volume production as well as presents a concept for the integration of the developed processes and modular machines onto a platform to form a "POLYTUBES Micro-Factory", being resulting from...... the European FP7 POLYTUBES project which aimed at the de-velopment of new process capabilities and equipment for the shaping of polymeric micro-tubes into functional mi-cro-components....

  4. Extracellular polymeric substances for Zn (II) binding during its sorption process onto aerobic granular sludge.

    Science.gov (United States)

    Wei, Dong; Li, Mengting; Wang, Xiaodong; Han, Fei; Li, Lusheng; Guo, Jie; Ai, Lijie; Fang, Lulu; Liu, Ling; Du, Bin; Wei, Qin

    2016-01-15

    The aim of this study was to evaluate the interaction between extracellular polymeric substances (EPS) and Zn (II) during the sorption process of Zn (II) onto aerobic granular sludge. Batch results showed that the adsorption rate of Zn (II) onto aerobic granular sludge was better fitted with pseudo-second order kinetics model, and the adsorption isotherm data agreed well with Freundlich equation. Extracellular polymeric substances (EPS) for Zn (II) binding during sorption process was investigated by using a combination of three-dimensional excitation-emission matrix (3D-EEM), synchronous fluorescence spectra, two-dimensional correlation spectroscopy (2D-COS) and Fourier transform infrared spectroscopy (FTIR). Results implied that the main composes of EPS, including polysaccharide (PS) and protein (PN), decreased from 5.92±0.13 and 23.55±0.76 mg/g SS to 4.11±0.09 and 9.55±0.68 mg/g SS after the addition of different doses of Zn (II). 3D-EEM showed that the intensities of PN-like substances and humic-like substances were obviously decreased during the sorption process. According to synchronous fluorescence spectra, the quenching mechanism between PN-like substances and Zn (II) was mainly caused by a static quenching process. Additionally, 2D-COS indicated that PN-like substances were more susceptible to Zn (II) binding than humic-like substances. It was also found that the main functional groups for complexation of Zn (II) and EPS were OH groups, N-H groups and C=O stretching vibration. The findings of this study are significant to reveal the fate of heavy metal during its sorption process onto aerobic granular sludge through EPS binding, and provide useful information on the interaction between EPS and heavy metal.

  5. Extracellular polymeric substances mediate bioleaching/biocorrosion via interfacial processes involving iron(III) ions and acidophilic bacteria.

    Science.gov (United States)

    Sand, Wolfgang; Gehrke, Tilman

    2006-01-01

    Extracellular polymeric substances seem to play a pivotal role in biocorrosion of metals and bioleaching, biocorrosion of metal sulfides for the winning of precious metals as well as acid rock drainage. For better control of both processes, the structure and function of extracellular polymeric substances of corrosion-causing or leaching bacteria are of crucial importance. Our research focused on the extremophilic bacteria Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans, because of the "simplicity" and knowledge about the interactions of these bacteria with their substrate/substratum and their environment. For this purpose, the composition of the corresponding extracellular polymeric substances and their functions were analyzed. The extracellular polymeric substances of both species consist mainly of neutral sugars and lipids. The functions of the exopolymers seem to be: (i) to mediate attachment to a (metal) sulfide surface, and (ii) to concentrate iron(III) ions by complexation through uronic acids or other residues at the mineral surface, thus, allowing an oxidative attack on the sulfide. Consequently, dissolution of the metal sulfide is enhanced, which may result in an acceleration of 20- to 100-fold of the bioleaching process over chemical leaching. Experiments were performed to elucidate the importance of the iron(III) ions complexed by extracellular polymeric substances for strain-specific differences in oxidative activity for pyrite. Strains of A. ferrooxidans with a high amount of iron(III) ions in their extracellular polymeric substances possess greater oxidation activity than those with fewer iron(III) ions. These data provide insight into the function of and consequently the advantages that extracellular polymeric substances provide to bacteria. The role of extracellular polymeric substances for attachment under the conditions of a space station and resulting effects like biofouling, biocorrosion, malodorous gases, etc. will be discussed.

  6. Molecular processes in plasmas collisions of charged particles with molecules

    CERN Document Server

    Itikawa, Yukikazu

    2007-01-01

    Molecular Processes in Plasmas describes elementary collision processes in plasmas, particularly those involving molecules or molecular ions. Those collision processes (called molecular processes) maintain plasmas, produce reactive species and emissions, and play a key role in energy balance in plasmas or more specifically in determining the energy distribution of plasma particles. Many books on plasma physics mention the elementary processes, but normally rather briefly. They only touch upon the general feature or fundamental concept of the collision processes. On the other hand, there are many books on atomic and molecular physics, but most of them are too general or too detailed to be useful to people in the application fields. The present book enumerates all the possible processes in the collisions of electrons, as well as ions, with molecules. For each process, a compact but informative description of its characteristics is given together with illustrative examples. Since the author has much experience a...

  7. Lagrangian coherent structures and plasma transport processes

    CERN Document Server

    Falessi, M V; Schep, T J

    2015-01-01

    A dynamical system framework is used to describe transport processes in plasmas embedded in a magnetic field. For periodic systems with one degree of freedom the Poincar\\'e map provides a splitting of the phase space into regions where particles have different kinds of motion: periodic, quasi-periodic or chaotic. The boundaries of these regions are transport barriers; i.e., a trajectory cannot cross such boundaries during the whole evolution of the system. Lagrangian Coherent Structure (LCS) generalize this method to systems with the most general time dependence, splitting the phase space into regions with different qualitative behaviours. This leads to the definition of finite-time transport barriers, i.e. trajectories cannot cross the barrier for a finite amount of time. This methodology can be used to identify fast recirculating regions in the dynamical system and to characterize the transport between them.

  8. A novel scalable synthesis process of PPTA by coupling n-pentane evaporation for polymerization heat removal

    Institute of Scientific and Technical Information of China (English)

    Tao Zhang; Guo Hua Luo; Fei Wei; Yan Yan Lu; Wei Zhong Qian; Xin Lin Tuo

    2011-01-01

    In this study, we compared the effect of n-pentane and ice-water bath on removing the thermal effect in the poly (p-phenylene terephthalamide) (PPTA) polymerization process. The results indicate that the n-pentane can help to transfer the reaction heat faster and better. Adding suitable amount of n-pentanes into the PPTA preparation process not only improve the heat transfer, but also reduce the motor power in the polymerization process. Moreover, the introduction of n-pentane properly does not result in decrease of the inherent viscosity (η7inh) of polymer. Instead, it leads to increased viscosity of polymer during the PPTA preparation process. The results indicate that n-pentane can effectively transfer the reaction heat and avoid overheating during the polymerization of PPTA.

  9. Plasma Discharge Process in a Pulsed Diaphragm Discharge System

    Science.gov (United States)

    Duan, Jianjin; Hu, Jue; Zhang, Chao; Wen, Yuanbin; Meng, Yuedong; Zhang, Chengxu

    2014-12-01

    As one of the most important steps in wastewater treatment, limited study on plasma discharge process is a key challenge in the development of plasma applications. In this study, we focus on the plasma discharge process of a pulsed diaphragm discharge system. According to the analysis, the pulsed diaphragm discharge proceeds in seven stages: (1) Joule heating and heat exchange stage; (2) nucleated site formation; (3) plasma generation (initiation of the breakdown stage); (4) avalanche growth and plasma expansion; (5) plasma contraction; (6) termination of the plasma discharge; and (7) heat exchange stage. From this analysis, a critical voltage criterion for breakdown is obtained. We anticipate this finding will provide guidance for a better application of plasma discharges, especially diaphragm plasma discharges.

  10. Tailoring the surface properties of polypropylene films through cold atmospheric pressure plasma (CAPP) assisted polymerization and immobilization of biomolecules for enhancement of anti-coagulation activity

    Energy Technology Data Exchange (ETDEWEB)

    Navaneetha Pandiyaraj, K., E-mail: dr.knpr@gmail.com [Surface Engineering Laboratory, Department of Physics, Sri Shakthi Institute of Engineering and Technology, L& T By Pass, Chinniyam Palayam (Post), Coimbatore 641062 (India); Ram Kumar, M.C.; Arun Kumar, A. [Surface Engineering Laboratory, Department of Physics, Sri Shakthi Institute of Engineering and Technology, L& T By Pass, Chinniyam Palayam (Post), Coimbatore 641062 (India); Padmanabhan, P.V.A. [PSN College of Engineering and Technology, Tirunelveli 627 152 (India); Deshmukh, R.R. [Department of Physics, Institute of Chemical Technology, Matunga, Mumbai 400 019 (India); Bah, M.; Ismat Shah, S. [Department of Physics and Astronomy, Department of Materials Science and Engineering, University of Delaware, 208 Dupont Hall, Newark (United States); Su, Pi-Guey [Department of Chemistry, Chinese Culture University, Taipei 111, Taiwan (China); Halleluyah, M.; Halim, A.S. [School of Medical Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan (Malaysia)

    2016-05-01

    Graphical abstract: - Highlights: • Developed low cost cold atmospheric plasma reactor for plasma polymerization technique. • Surface of the PP film was modified by grafting of AAc and PEG by CAPP polymerization. • Biomolecules of chitosan, insulin and heparin were immobilized on surface of PEG-AAc grafted PP films. • The surface modified PP films were characterized by various techniques. • The plasma polymerized and immobilized film reveals substantial blood compatibility. - Abstract: Enhancement of anti-thrombogenic properties of polypropylene (PP) to avert the adsorption of plasma proteins (fibrinogen and albumin), adhesion and activation of the platelets are very important for vast biomedical applications. The cold atmospheric pressure plasma (CAPP) assisted polymerization has potential to create the specific functional groups such as O−C=O, C=O, C−N and S−S. on the surface of polymeric films using selective precursor in vapour phase to enhance anti-thrombogenic properties. Such functionalized polymeric surfaces would be suitable for various biomedical applications especially to improve the blood compatibility. The eventual aspiration of the present investigation is to develop the biofunctional coating onto the surface of PP films using acrylic acid (AAc) and polyethylene glycol (PEG) as a precursor in a vapour phase by incorporating specific functional groups for immobilization of biomolecules such as heparin (HEP), chitosan (CHI) and insulin (INS) on the surface of plasma modified PP films. The surface properties such as hydrophilicity, chemical composition, surface topography of the surface modified PP films were analyzed by contact angle (CA), Fourier transform infrared spectroscopy (FTIR), X-ray photo electron spectroscopy (XPS) and atomic force microscopy (AFM). Furthermore the anti-thrombogenic properties of the surface modified PP films were studied by in vitro tests which include platelet adhesion and protein adsorption analysis. It was

  11. Physical processes associated with current collection by plasma contactors

    Science.gov (United States)

    Katz, Ira; Davis, Victoria A.

    1990-01-01

    Recent flight data confirms laboratory observations that the release of neutral gas increases plasma sheath currents. Plasma contactors are devices which release a partially ionized gas in order to enhance the current flow between a spacecraft and the space plasma. Ionization of the expellant gas and the formation of a double layer between the anode plasma and the space plasma are the dominant physical processes. A theory is presented of the interaction between the contactor plasma and the background plasma. The conditions for formation of a double layer between the two plasmas are derived. Double layer formation is shown to be a consequence of the nonlinear response of the plasmas to changes in potential. Numerical calculations based upon this model are compared with laboratory measurements of current collection by hollow cathode-based plasma contactors.

  12. Influence of dielectric constant of polymerization medium on processability and ammonia gas sensing properties of polyaniline

    Indian Academy of Sciences (India)

    Partha Pratim Sengupta; Pradip Kar; Basudam Adhikari

    2011-04-01

    Polyaniline (PANI) was synthesized by the oxidation of aniline hydrochloride in the presence of ammonium persulphate and hydrochloric acid. The polymerization reaction was carried out in several batches in different solvent media by changing the volume ratio of ,-dimethyl formamide (DMF) and water as binary solvent mixture. The dielectric constant of the polymerizationmedium for each batch reaction was determined by measuring the capacitance with change in frequency. The UV spectra of the synthesized polyaniline solutions helped us to optimize the ratio of the binary solvent to get sufficient polymer growth and processability. Thin film of processable polyaniline was then deposited on glass slides coated with polyvinyl alcohol (PVA) crosslinked with maleic anhydride (MA). FTIR and XRD studies of the coated film were also done. AFM studies further helped in the morphological study of the film deposited. Finally, conductivity and ammonia gas-sensing property of the polyaniline film were also studied.

  13. Effect of Barley β-Glucan on the Gluten Polymerization Process in Dough during Heat Treatment.

    Science.gov (United States)

    Huang, Ze-Hua; Zhao, Yang; Zhu, Ke-Xue; Guo, Xiao-Na; Peng, Wei; Zhou, Hui-Ming

    2017-07-26

    Barley (Hordeum vulgare L.) β-glucan (BBG) is of interest as a result of its health benefits, but BBG presents significant disruptions on the gluten network, with a negative impact on food texture. To clarify the interaction between BBG and gluten in dough, the dynamic rheological, thermochemical process of gluten and microstructure of dough with BBG during heating were detected. The results showed that BBG delayed the gluten thermopolymerization reaction during heating and affected polymerization of specific molecular weight protein subunits. These impacts depended upon the heating temperature and time. When heating under 25-65 °C, tan δ of the dough reached the highest level at the BBG concentration of 1%. However, under the temperature of 65-95 °C, tan δ was positively correlated with the BBG content (0-3%). The differential scanning calorimetry curves revealed that the peak temperature (TP) of the two endothermic peaks increased by 3.86 and 3.10 °C. Size-exclusion high-performance liquid chromatography analysis showed that BBG mainly affected the peak area of gliadin and glutenin. Furthermore, after 3% BBG was added, the bands of 59.8 and 64.9 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns delayed, vanishing for 120 s when heating at 95 °C. Therefore, BBG delayed the polymerization reaction of specific molecular weight protein subunits rather than all of the proteins.

  14. Process Chain for the Manufacture of Polymeric Tubular Micro-Components and “POLYTUBES Micro-Factory” Concept

    DEFF Research Database (Denmark)

    Qin, Yi; Perzon, Erik; Chronakis, Ioannis S.

    The paper presents a process chain for the shaping of poly-meric tubular micro-components for the volume production as well as presents a concept for the integration of the developed processes and modular machines onto a platform to form a "POLYTUBES Micro-Factory", being resulting from the Europ...... the European FP7 POLYTUBES project which aimed at the de-velopment of new process capabilities and equipment for the shaping of polymeric micro-tubes into functional mi-cro-components....

  15. Surface Modification of Polypropylene Microporous Membrane by Atmospheric-pressure Plasma Induced N-vinyl-2-pyrrolidone Graft Polymerization

    Institute of Scientific and Technical Information of China (English)

    ZHONG Shaofeng

    2012-01-01

    Membrane surfaces modified with poly(N-vinyl-2-pyrrolidone) (PNVP) can be endowed with hydrophilicity,biocompatibility and functionality.In this work,atmospheric pressure dielectric barrier discharge plasma graft polymerization of N-vinyl-2-pyrrolidone (NVP) onto polypropylene (PP) microporous membrane surface was studied.The experimental results reveal that plasma treatment conditions,such as discharge power,treatment time and adsorbed NVP amount,have remarkable effects on the grafting degree of NVP.Structural and morphological changes on the membrane surfaces were characterized by attenuated total reflection-Fourier transform infrared spectroscopy (FT-IR/ATR),X-ray photoelectron spectroscope (XPS) and field emission scanning electron microscopy (FE-SEM).Water contact angles of the membrane surfaces were also measured by the sessile drop method.Water contact angles on the membrane surfaces decrease with the increase of NVP grafting degree,which indicates an enhanced hydrophilicity for the modified membranes.The effects of grafting degrees on pure water fluxes were also measured.It is shown that pure water fluxes increase with grafting degree firstly and then decrease adversely.Finally,filtration of bovine serum albumin (BSA) solution and platelets adhesion of the PNVP modified membranes show good protein resistance and potential biocompatibility due to the enhancement of surface hydrophilicity.

  16. Influence of bowl shaped substrate holder on growth of polymeric DLC film in a microwave plasma CVD reactor

    Indian Academy of Sciences (India)

    Sambita Sahoo; S K Pradhan; Venkateswarlu Bhavanasi; Swati S Pradhan; S N Sarangi; P K Barhai

    2012-12-01

    The properties of diamond like carbon (DLC) films grown in modified microwave plasma CVD reactor is presented in this paper. By using bowl shaped steel substrate holder in a MW plasma CVD reactor (without ECR), films have been grown at relatively high pressure (20Torr) and at low temperature (without heating). The input microwave power was about 300W. Earlier, under the same growth conditions, no deposition was achieved when flat molybdenum/steel substrate holders were used. In this study, two different designs of bowl shaped steel substrate holder at different bias have been experimented. Raman spectra confirm the DLC characteristics of the films. FTIR results indicate that the carbon is bonded in the 3 form with hydrogen, and this characteristic is more pronounced when smaller holder is used. UV-visible spectra show high visible transmittance (∼85%) for films grown in both the holders. The nanoindentation hardness of the films have a wide range, about 4–16GPa. Field emission scanning electron microscope (FESEM) images reveal that the films have featureless and smooth surface morphology. These films are polymeric in nature with moderately high hardness, which may be useful as anti-scratch and anti-corrosive coatings.

  17. In situ plasma fabrication of ceramic-like structure on polymeric implant with enhanced surface hardness, cytocompatibility and antibacterial capability.

    Science.gov (United States)

    Liu, Jun; Zhang, Wei; Shi, Haigang; Yang, Kun; Wang, Gexia; Wang, Pingli; Ji, Junhui; Chu, Paul K

    2016-05-01

    Polymeric materials are commonly found in orthopedic implants due to their unique mechanical properties and biocompatibility but the poor surface hardness and bacterial infection hamper many biomedical applications. In this study, a ceramic-like surface structure doped with silver is produced by successive plasma implantation of silicon (Si) and silver (Ag) into the polyamine 66 (PA66) substrate. Not only the surface hardness and elastic modulus are greatly enhanced due to the partial surface carbonization and the ceramic-like structure produced by the reaction between energetic Si and the carbon chain of PA66, but also the antibacterial activity is improved because of the combined effects rendered by Ag and SiC structure. Furthermore, the modified materials which exhibit good cytocompatibility upregulate bone-related genes and proteins expressions of the contacted bone mesenchymal stem cells (BMSCs). For the first time, it explores out that BMSCs osteogenesis on the antibacterial ceramic-like structure is mediated via the iNOS and nNOS signal pathways. The results reveal that in situ plasma fabrication of an antibacterial ceramic-like structure can endow PA66 with excellent surface hardness, cytocompatibility, as well as antibacterial capability.

  18. Humidity-independent conducting polyaniline films synthesized using advanced atmospheric pressure plasma polymerization with in-situ iodine doping

    Science.gov (United States)

    Park, Choon-Sang; Kim, Do Yeob; Kim, Dong Ha; Lee, Hyung-Kun; Shin, Bhum Jae; Tae, Heung-Sik

    2017-01-01

    This study reports on the synthesis and characterization of conducting polyaniline (PANI) thin films when using advanced atmospheric pressure plasma jets (APPJs). A simple method for synthesizing conducting polymers (CPs) with humidity-independent characteristics is introduced using advanced APPJs and an in-situ iodine doping method. In the case of ex-situ I2 doping, a humidity effect study showed that increasing the relative humidity produced significant changes in the electrical resistance (R) of the PANI, indicating strong humidity-dependent characteristics similar to conventional CPs. In contrast, in the case of in-situ I2 doping, the R and sensitivity of the PANI remained essentially unchanged when increasing the relative humidity, except for a very low sensitivity of 0.5% under 94% relative humidity. In addition, the R for the PANI with in-situ I2 doping showed no aging effect, while the R for the ex-situ-doped PANI increased dramatically over time. Thus, it is anticipated that the use of in-situ doping during plasma polymerization can be widely used to design stable and high-performance CPs with humidity-independent characteristics for a variety of applications.

  19. Atmospheric Pressure Plasma Processing for Polymer Adhesion: A Review

    DEFF Research Database (Denmark)

    Kusano, Yukihiro

    2014-01-01

    Atmospheric pressure plasma processing has attracted significant interests over decades due to its usefulness and a variety of applications. Adhesion improvement of polymer surfaces is among the most important applications of atmospheric pressure plasma treatment. Reflecting recent significant de...... development of the atmospheric pressure plasma processing, this work presents its fundamental aspects, applications, and characterization techniques relevant to adhesion.......Atmospheric pressure plasma processing has attracted significant interests over decades due to its usefulness and a variety of applications. Adhesion improvement of polymer surfaces is among the most important applications of atmospheric pressure plasma treatment. Reflecting recent significant...

  20. Microbial adherence to a nonprecious alloy after plasma nitriding process.

    Science.gov (United States)

    Sonugelen, Mehmet; Destan, Uhmut Iyiyapici; Lambrecht, Fatma Yurt; Oztürk, Berran; Karadeniz, Süleyman

    2006-01-01

    To investigate the microbial adherence to the surfaces of a nonprecious metal alloy after plasma nitriding. The plasma-nitriding process was performed to the surfaces of metals prepared from a nickel-chromium alloy. The microorganisms were labeled with technetium-99m. After the labeling procedure, 60 metal disks were treated with a microorganism for each use. The results revealed that the amount of adherence of all microorganisms on surfaces was changed by plasma-nitriding process; adherence decreased substantially (P plasma nitriding time were not significant (P> .05) With the plasma-nitriding process, the surface properties of nonprecious metal alloys can be changed, leading to decreased microbial adherence.

  1. Preliminary Hazards Analysis Plasma Hearth Process

    Energy Technology Data Exchange (ETDEWEB)

    Aycock, M.; Coordes, D.; Russell, J.; TenBrook, W.; Yimbo, P. [Science Applications International Corp., Pleasanton, CA (United States)

    1993-11-01

    This Preliminary Hazards Analysis (PHA) for the Plasma Hearth Process (PHP) follows the requirements of United States Department of Energy (DOE) Order 5480.23 (DOE, 1992a), DOE Order 5480.21 (DOE, 1991d), DOE Order 5480.22 (DOE, 1992c), DOE Order 5481.1B (DOE, 1986), and the guidance provided in DOE Standards DOE-STD-1027-92 (DOE, 1992b). Consideration is given to ft proposed regulations published as 10 CFR 830 (DOE, 1993) and DOE Safety Guide SG 830.110 (DOE, 1992b). The purpose of performing a PRA is to establish an initial hazard categorization for a DOE nuclear facility and to identify those processes and structures which may have an impact on or be important to safety. The PHA is typically performed during and provides input to project conceptual design. The PRA then is followed by a Preliminary Safety Analysis Report (PSAR) performed during Title I and II design. This PSAR then leads to performance of the Final Safety Analysis Report performed during construction, testing, and acceptance and completed before routine operation. Radiological assessments indicate that a PHP facility, depending on the radioactive material inventory, may be an exempt, Category 3, or Category 2 facility. The calculated impacts would result in no significant impact to offsite personnel or the environment. Hazardous material assessments indicate that a PHP facility will be a Low Hazard facility having no significant impacts either onsite or offsite to personnel and the environment.

  2. Plasma generated during underwater pulsed laser processing

    Science.gov (United States)

    Hoffman, Jacek; Chrzanowska, Justyna; Moscicki, Tomasz; Radziejewska, Joanna; Stobinski, Leszek; Szymanski, Zygmunt

    2017-09-01

    The plasma induced during underwater pulsed laser ablation of graphite is studied both experimentally and theoretically. The results of the experiment show that the maximum plasma temperature of 25000 K is reached 20 ns from the beginning of the laser pulse and decreases to 6500 K after 1000 ns. The observed OH absorption band shows that the plasma plume is surrounded by the thin layer of dissociated water vapour at a temperature around 5500 K. The hydrodynamic model applied shows similar maximum plasma temperature at delay times between 14 ns and 30 ns. The calculations show also that already at 14th ns, the plasma electron density reaches 0.97·1027 m-3, which is the critical density for 1064 nm radiation. At the same time the plasma pressure is 2 GPa, which is consisted with earlier measurements of the peak pressure exerted on a target in similar conditions.

  3. New green polymeric composites based on hemp and natural rubber processed by electron beam irradiation.

    Science.gov (United States)

    Stelescu, Maria-Daniela; Manaila, Elena; Craciun, Gabriela; Dumitrascu, Maria

    2014-01-01

    A new polymeric composite based on natural rubber reinforced with hemp has been processed by electron beam irradiation and characterized by several methods. The mechanical characteristics: gel fraction, crosslink density, water uptake, swelling parameters, and FTIR of natural rubber/hemp fiber composites have been investigated as a function of the hemp content and absorbed dose. Physical and mechanical properties present a significant improvement as a result of adding hemp fibres in blends. Our experiments showed that the hemp fibers have a reinforcing effect on natural rubber similar to mineral fillers (chalk, carbon black, silica). The crosslinking rates of samples, measured using the Flory-Rehner equation, increase as a result of the amount of hemp in blends and the electron beam irradiation dose increasing. The swelling parameters of samples significantly depend on the amount of hemp in blends, because the latter have hydrophilic characteristics.

  4. New Green Polymeric Composites Based on Hemp and Natural Rubber Processed by Electron Beam Irradiation

    Directory of Open Access Journals (Sweden)

    Maria-Daniela Stelescu

    2014-01-01

    Full Text Available A new polymeric composite based on natural rubber reinforced with hemp has been processed by electron beam irradiation and characterized by several methods. The mechanical characteristics: gel fraction, crosslink density, water uptake, swelling parameters, and FTIR of natural rubber/hemp fiber composites have been investigated as a function of the hemp content and absorbed dose. Physical and mechanical properties present a significant improvement as a result of adding hemp fibres in blends. Our experiments showed that the hemp fibers have a reinforcing effect on natural rubber similar to mineral fillers (chalk, carbon black, silica. The crosslinking rates of samples, measured using the Flory-Rehner equation, increase as a result of the amount of hemp in blends and the electron beam irradiation dose increasing. The swelling parameters of samples significantly depend on the amount of hemp in blends, because the latter have hydrophilic characteristics.

  5. Encapsulation and controlled release from core-shell nanoparticles fabricated by plasma polymerization

    Science.gov (United States)

    Shahravan, Anaram; Matsoukas, Themis

    2012-01-01

    Core-shell nanostructures have been synthesized by plasma deposition in radio-frequency plasma reactor. Silica and KCl nanoparticles were encapsulated by deposition of isopropanol-based films of amorphous hydrogenated carbon. Through control of the deposition time, under constant deposition rate of 1 nm/min, particles are encapsulated in a layer of plasma polymer with thickness between 15 and 100 nm. Films are robust, chemically inert, thermally stable up to 250°C. The permeability of the shells is determined by depositing films of various thickness onto KCl nanoparticles and monitoring the dissolution of the core in aqueous solution. The dissolution profile is characterized by an initial rapid release, followed by a slow release that lasts up to 30 days for the thickest films. The profile is analyzed by Fickian diffusion through a spherical matrix. We find that this model captures very accurately the entire release profile except for the first 12 hours during which, the dissolution rate is higher than that predicted by the model. The overall diffusion coefficient for the dissolution of KCl is 3 × 10-21 m2/s.

  6. Two-Step Plasma Process for Cleaning Indium Bonding Bumps

    Science.gov (United States)

    Greer, Harold F.; Vasquez, Richard P.; Jones, Todd J.; Hoenk, Michael E.; Dickie, Matthew R.; Nikzad, Shouleh

    2009-01-01

    A two-step plasma process has been developed as a means of removing surface oxide layers from indium bumps used in flip-chip hybridization (bump bonding) of integrated circuits. The two-step plasma process makes it possible to remove surface indium oxide, without incurring the adverse effects of the acid etching process.

  7. Status and challenges in electrical diagnostics of processing plasmas

    DEFF Research Database (Denmark)

    Stamate, Eugen

    2014-01-01

    Dry processing based on reactive plasmas was the main driven force for micro- and recently nano-electronic industry. Once with the increasing in plasma complexity new diagnostics methods have been developed to ensure a proper process control during etching, thin film deposition, ion implantation...... or other steps in device fabrication. This work reviews some of the unconventional methods developed in the last two decays to measure the parameters of reactive plasmas including, the test function method, thermal probes, and plasma-sheath-lens probes. The negative ion detection and surface contamination...... in plasmas with a high degree of contamination are also addressed. (C) 2014 Elsevier B.V. All rights reserved....

  8. A review on the processing accuracy of two-photon polymerization

    Directory of Open Access Journals (Sweden)

    Xiaoqin Zhou

    2015-03-01

    Full Text Available Two-photon polymerization (TPP is a powerful and potential technology to fabricate true three-dimensional (3D micro/nanostructures of various materials with subdiffraction-limit resolution. And it has been applied to microoptics, electronics, communications, biomedicine, microfluidic devices, MEMS and metamaterials. These applications, such as microoptics and photon crystals, put forward rigorous requirements on the processing accuracy of TPP, including the dimensional accuracy, shape accuracy and surface roughness and the processing accuracy influences their performance, even invalidate them. In order to fabricate precise 3D micro/nanostructures, the factors influencing the processing accuracy need to be considered comprehensively and systematically. In this paper, we review the basis of TPP micro/nanofabrication, including mechanism of TPP, experimental set-up for TPP and scaling laws of resolution of TPP. Then, we discuss the factors influencing the processing accuracy. Finally, we summarize the methods reported lately to improve the processing accuracy from improving the resolution and changing spatial arrangement of voxels.

  9. A review on the processing accuracy of two-photon polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xiaoqin; Hou, Yihong [School of Mechanical Science and Engineering, Jilin University, Changchun, 130022 (China); Lin, Jieqiong, E-mail: linjieqiong@mail.ccut.edu.cn [School of Electromechanical Engineering, Changchun University of Technology, Changchun, 130012 (China)

    2015-03-15

    Two-photon polymerization (TPP) is a powerful and potential technology to fabricate true three-dimensional (3D) micro/nanostructures of various materials with subdiffraction-limit resolution. And it has been applied to microoptics, electronics, communications, biomedicine, microfluidic devices, MEMS and metamaterials. These applications, such as microoptics and photon crystals, put forward rigorous requirements on the processing accuracy of TPP, including the dimensional accuracy, shape accuracy and surface roughness and the processing accuracy influences their performance, even invalidate them. In order to fabricate precise 3D micro/nanostructures, the factors influencing the processing accuracy need to be considered comprehensively and systematically. In this paper, we review the basis of TPP micro/nanofabrication, including mechanism of TPP, experimental set-up for TPP and scaling laws of resolution of TPP. Then, we discuss the factors influencing the processing accuracy. Finally, we summarize the methods reported lately to improve the processing accuracy from improving the resolution and changing spatial arrangement of voxels.

  10. Understanding the charge carrier conduction mechanisms of plasma-polymerized 2-furaldehyde thin films via DC electrical studies

    Energy Technology Data Exchange (ETDEWEB)

    Kabir, Humayun, E-mail: HXK598@bham.ac.uk [Department of Physics, Jahangirnagar University, Savar, Dhaka 1342 (Bangladesh); School of Metallurgy and Materials, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Bhuiyan, A.H. [Department of Physics, Bangladesh University of Engineering & Technology, Dhaka 1000 (Bangladesh); Rahman, M. Mahbubur [Department of Physics, Jahangirnagar University, Savar, Dhaka 1342 (Bangladesh); Surface Analysis and Materials Engineering Research Group, School of Engineering & Information Technology, Murdoch University, Perth, Western Australia 6150 (Australia)

    2016-06-30

    Monomer 2-furaldehyde (FDH) was deposited onto the glass substrates in optimum conditions via a glow discharge using a capacitively coupled parallel plate reactor to obtain plasma polymerized 2-furaldehyde (PPFDH) thin films of different thicknesses. In order to realize the carrier conduction mechanisms, the direct current density against applied voltage (J–V) characteristics of these films with different thicknesses were investigated at different temperatures (T) in the voltage region from 0.5 to 49 V in Al/PPFDH/Al sandwich configuration. The J–V characteristics at various temperatures follow a power law of the form J ∞ V{sup n}. In the low voltage region the values of n were recorded to be 0.80 ≤ n ≤ 1.12 and those in the high voltage region found to lie between 1.91 ≤ n ≤ 2.58, demonstrating the Ohmic conduction mechanism in the low voltage region and non-Ohmic conduction in the high voltage region. Theoretically calculated and experimental results of Schottky (β{sub s}) and Poole–Frenkel (β{sub PF}) coefficients display that the most probable conduction mechanism in PPFDH thin films is the Schottky type. Arrhenius plots of J vs. 1/T for an applied voltage of 5 V, the activation energies were 0.13 ± 0.02 and 0.50 ± 0.05 eV in the low and high temperature regions, respectively. However, for an applied voltage of 35 V, the activation energy values were found to be 0.11 ± 0.01 eV and 0.55 ± 0.02 eV, respectively in low and high temperature regions. - Highlights: • Plasma polymerized 2-furaldehyde films were synthesized via a glow discharge technique. • Uniformity of the surface of the PPDFH films was identified via SEM analysis. • Energy dispersive X-ray spectra show the presence of C, O, and substrate related elements. • The dominant conduction mechanism in the PPFDH films is of Schottky type. • Schottky type mechanism was also confirmed by the temperature dependence J–V studies.

  11. 聚醋酸乙烯酯/纳米ZnO颗粒复合材料的等离子聚合及其光学性能%Fabrication and Optical Properties of PVAC-functionalized ZnO Nanoparticles through Plasma Polymerization Process

    Institute of Scientific and Technical Information of China (English)

    杨慧慧; 黄荣进; 黄传军; 张浩; 李来风; 徐向东

    2011-01-01

    Surface modification of ZnO nanoparticle with polyvinyl acetate was conducted throughplasma polymerization process. The surface morphology and structure of the functionalized ZnO nanoparticles were investigated. The influence of surface modification on optical properties was examined. The results indicated that a uniform layer with a thickness of 3-7 nm formed on the surface of the ZnO nanoparticles. The thin layer on the surface of the ZnO nanoparticles was found to be polyvinyl acetate (PVAC). Moreover, ageing test for two years indicated that the adhesion behavior between the organic VAC and the inorganic ZnO nanoparticles was good. In marked contrast to the uncoated ZnO nanoparticles, the surface modification resulted in significant decrease of PL intensity. UV/Vis spectra revealed that the PVAC-functionalized ZnO nanoparticles show strong absorption of UV light at wavelengths between 200 and 800 nm while the optical transparency in the visible region was slightly below that of the untreated ZnO nanoparticles.%采用等离子镀膜方法在纳米ZnO颗粒表面沉积一层有机薄膜,制备出聚合物/ZnO复合材料.用高分辨透射电子显微镜(HRTEM)、傅立叶变换红外光谱(FTIR)、光致发光光谱(PL)和紫外-可见吸收光谱(UV-Vi8)对其形貌、结构和性能进行表征,研究了聚合物/ZnO复合材料的光学性能以及聚合物与纳米ZnO颗粒的结合强度.结果表明,用等离子镀膜法可在纳米ZnO颗粒表面沉积一层醋酸乙烯酯(VAC)聚合物薄膜,薄膜与无机纳米ZnO颗粒以共价键形式结合,结合牢固.这层聚合物薄膜改变了纳米ZnO的表面性能,导致聚合物/ZnO复合材料的紫外-可见吸收能力增强而光致发光性能降低.

  12. Atomic processes in high-density plasmas

    Energy Technology Data Exchange (ETDEWEB)

    More, R.M.

    1982-12-21

    This review covers dense atomic plasmas such as that produced in inertial confinement fusion. The target implosion physics along with the associated atomic physics, i.e., free electron collision phenomena, electron states I, electron states II, and nonequilibrium plasma states are described. (MOW)

  13. Aging effects of plasma polymerized ethylenediamine (PPEDA) thin films on cell-adhesive implant coatings

    Energy Technology Data Exchange (ETDEWEB)

    Testrich, H., E-mail: holger.testrich@uni-greifswald.de [University of Greifswald, Institute of Physics, Felix-Hausdorff Str. 6, 17489 Greifswald (Germany); Rebl, H. [University of Rostock, Biomedical Research Center, Department of Cell Biology, Schillingallee 69, 18057 Rostock (Germany); Finke, B.; Hempel, F. [Leibniz Institute for Plasma Science and Technology, Felix-Hausdorff Str. 2, 17489 Greifswald (Germany); Nebe, B. [University of Rostock, Biomedical Research Center, Department of Cell Biology, Schillingallee 69, 18057 Rostock (Germany); Meichsner, J. [University of Greifswald, Institute of Physics, Felix-Hausdorff Str. 6, 17489 Greifswald (Germany)

    2013-10-15

    Thin plasma polymer films from ethylenediamine were deposited on planar substrates placed on the powered electrode of a low pressure capacitively coupled 13.56 MHz discharge. The chemical composition of the plasma polymer films was analyzed by Fourier Transform Infrared Reflection Absorption Spectroscopy (FT-IRRAS) as well as by X-ray photoelectron spectroscopy (XPS) after derivatization of the primary amino groups. The PPEDA films undergo an alteration during the storage in ambient air, particularly, due to reactions with oxygen. The molecular changes in PPEDA films were studied over a long-time period of 360 days. Simultaneously, the adhesion of human osteoblast-like cells MG-63 (ATCC) was investigated on PPEDA coated corundum blasted titanium alloy (Ti-6Al-4V), which is applied as implant material in orthopedic surgery. The cell adhesion was determined by flow cytometry and the cell shape was analyzed by scanning electron microscopy. Compared to uncoated reference samples a significantly enhanced cell adhesion and proliferation were measured for PPEDA coated samples, which have been maintained after long-time storage in ambient air and additional sterilization by γ−irradiation. - Highlights: • Development of cell-adhesive nitrogen-rich coatings for biomedical applications. • Plasma polymer films from low pressure 13.56 MHz discharge in argon-ethylenediamine. • Enhanced osteoblast adhesion/proliferation on coated implant material (Ti-6Al-4V). • Despite film aging over 360 days the enhanced cell adhesion of the coating remains. • No influence of additional y-sterilization on the enhanced cell adhesion.

  14. Mimicking the Nanostructure of Bone: Comparison of Polymeric Process-Directing Agents

    Directory of Open Access Journals (Sweden)

    Laurie B. Gower

    2010-12-01

    Full Text Available The nanostructure of bone has been replicated using a polymer-induced liquid-precursor (PILP mineralization process. This polymer-mediated crystallization process yields intrafibrillar mineralization of collagen with uniaxially-oriented hydroxyapatite crystals. The process-directing agent, an anionic polymer which we propose mimics the acidic non-collagenous proteins associated with bone formation, sequesters calcium and phosphate ions to form amorphous precursor droplets that can infiltrate the interstices of collagen fibrils. In search of a polymeric agent that produces the highest mineral content in the shortest time, we have studied the influence of various acidic polymers on the in vitro mineralization of collagen scaffolds via the PILP process. Among the polymers investigated were poly-L-aspartic acid (PASP, poly-L-glutamic acid (PGLU, polyvinylphosphonic acid (PVPA, and polyacrylic acid (PAA. Our data indicate that PASP and the combination of PGLU/PASP formed stable mineralization solutions, and yielded nano-structured composites with the highest mineral content. Such studies contribute to our goal of preparing biomimetic bone graft substitutes with composition and structure that mimic bone.

  15. Thermomechanical processing of plasma sprayed intermetallic sheets

    Energy Technology Data Exchange (ETDEWEB)

    Hajaligol, Mohammad R. (Midlothian, VA); Scorey, Clive (Cheshire, CT); Sikka, Vinod K. (Oak Ridge, TN); Deevi, Seetharama C. (Midlothian, VA); Fleischhauer, Grier (Midlothian, VA); Lilly, Jr., A. Clifton (Chesterfield, VA); German, Randall M. (State College, PA)

    2001-01-01

    A powder metallurgical process of preparing a sheet from a powder having an intermetallic alloy composition such as an iron, nickel or titanium aluminide. The sheet can be manufactured into electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 4 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.0.05% Zr .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Ni, .ltoreq.0.75% C, .ltoreq.0.1% B, .ltoreq.1% submicron oxide particles and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, and/or .ltoreq.3% Cu. The process includes forming a non-densified metal sheet by consolidating a powder having an intermetallic alloy composition such as by roll compaction, tape casting or plasma spraying, forming a cold rolled sheet by cold rolling the non-densified metal sheet so as to increase the density and reduce the thickness thereof and annealing the cold rolled sheet. The powder can be a water, polymer or gas atomized powder which is subjecting to sieving and/or blending with a binder prior to the consolidation step. After the consolidation step, the sheet can be partially sintered. The cold rolling and/or annealing steps can be repeated to achieve the desired sheet thickness and properties. The annealing can be carried out in a vacuum furnace with a vacuum or inert atmosphere. During final annealing, the cold rolled sheet recrystallizes to an average grain size of about 10 to 30 .mu.m. Final stress relief annealing can be carried out in the B2 phase temperature range.

  16. Understanding plasma spraying process and characteristics of DC-arc plasma gun (PJ-100

    Directory of Open Access Journals (Sweden)

    Jovana Ružić

    2012-12-01

    Full Text Available The thermal spray processes are a group of coating processes used to apply metallic or non-metallic coatings. In these processes energy sources are used to heat the coating material (in the form of powder, wire, or rod form to a molten or semi-molten state and accelerated towards a prepared surface by either carrier gases or atomization jets. In plasma spraying process, the spraying material is generally in the form of powder and requires a carrier gas to feed the powder into the plasma jet, which is passing between the hot cathode and the cylindrical nozzle-shaped anode. The design of DC plasma gun (PJ - 100 is designed and manufactured in Serbia. Plasma spaying process, the powder injection with the heat, momentum and mass transfers between particles and plasma jet, and the latest developments related to the production of DC plasma gun are described in this article.

  17. Characterization of bioactive RGD peptide immobilized onto poly(acrylic acid) thin films by plasma polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Hyun Suk; Ko, Yeong Mu; Shim, Jae Won [Department of Dental Materials, School of Dentistry, MRC Center, Chosun University, Gwangju (Korea, Republic of); Lim, Yun Kyong; Kook, Joong-Ki [Department of Oral Biochemistry, School of Dentistry, Chosun University, Gwangju (Korea, Republic of); Cho, Dong-Lyun [School of Applied Chemical Engineering and Center for Functional Nano Fine Chemicals, Chonnam National University, Gwangju (Korea, Republic of); Kim, Byung Hoon, E-mail: kim5055@chosun.ac.kr [Department of Dental Materials, School of Dentistry, MRC Center, Chosun University, Gwangju (Korea, Republic of)

    2010-11-01

    Plasma surface modification can be used to improve the surface properties of commercial pure Ti by creating functional groups to produce bioactive materials with different surface topography. In this study, a titanium surface was modified with acrylic acid (AA) using a plasma treatment and immobilized with bioactive arginine-glycine-aspartic acid (RGD) peptide, which may accelerate the tissue integration of bone implants. Both terminals containing the -NH{sub 2} of RGD peptide sequence and -COOH of poly(acrylic acid) (PAA) thin film were combined with a covalent bond in the presence of 1-ethyl-3-3-dimethylaminopropyl carbodiimide (EDC). The chemical structure and morphology of AA film and RGD immobilized surface were investigated by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR), atomic force microscopy (AFM), and scanning electron microscopy (SEM). All chemical analysis showed full coverage of the Ti substrate with the PAA thin film containing COOH groups and the RGD peptide. The MC3T3-E1 cells were cultured on each specimen, and the cell alkaline phosphatase (ALP) activity were examined. The surface-immobilized RGD peptide has a significantly increased the ALP activity of MC3T3-E1 cells. These results suggest that the RGD peptide immobilization on the titanium surface has an effect on osteoblastic differentiation of MC3T3-E1 cells and potential use in osteo-conductive bone implants.

  18. Plasma-initiated polymerization of chitosan-based CS-g-P(AM-DMDAAC) flocculant for the enhanced flocculation of low-algal-turbidity water.

    Science.gov (United States)

    Sun, Yongjun; Zhu, Chengyu; Sun, Wenquan; Xu, Yanhua; Xiao, Xuefeng; Zheng, Huaili; Wu, Huifang; Liu, Cuiyun

    2017-05-15

    In this work, a highly efficient and environmentally friendly chitosan-based graft flocculant, namely, acrylamide- and dimethyl diallyl ammonium chloride-grafted chitosan [CS-g-P(AM-DMDAAC)], was prepared successfully through plasma initiation. FTIR results confirmed the successful polymerization of CS-g-P(AM-DMDAAC) and P(AM-DMDAAC). P(AM-DMDAAC) was the copolymer of acrylamide- and dimethyl diallyl ammonium chloride. SEM results revealed that a densely cross-linked network structure formed on the surface. XRD results verified that the ordered crystal structure of chitosan in CS-g-P(AM-DMDAAC) was changed into an amorphous structure after plasma-induced polymerization. The flocculation results of low-algal-turbidity water further showed the optimal flocculation efficiency of turbidity removal rate, COD removal rate, and Chl-a removal rate were 99.02%, 96.11%, and 92.20%, respectively. The flocculation efficiency of CS-g-P(AM-DMDAAC) were significantly higher than those obtained by cationic polyacrylamide (CPAM) and Polymeric aluminum and iron (PAFC). This work provided a valuable basis for the design of eco-friendly naturally modified polymeric flocculants to enhance the flocculation of low-algal-turbidity water. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Detailed investigation of optoelectronic and microstructural properties of plasma polymerized cyclohexane thin films: Dependence on the radiofrequency power

    Energy Technology Data Exchange (ETDEWEB)

    Manaa, C.; Bouaziz, L. [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, UFR des Sciences d' Amiens, 33 rue Saint Leu, 80039 Amiens Cedex 2 (France); Laboratoire de Matériaux Avancés et Phénomènes Quantiques, Université de Tunis El-Manar, Faculté des Sciences de Tunis, Campus universitaire El-Manar, 1068 Tunis (Tunisia); Lejeune, M.; Zellama, K., E-mail: kacem.zellama@u-picardie.fr; Benlahsen, M. [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, UFR des Sciences d' Amiens, 33 rue Saint Leu, 80039 Amiens Cedex 2 (France); Kouki, F.; Mejatty, M.; Bouchriha, H. [Laboratoire de Matériaux Avancés et Phénomènes Quantiques, Université de Tunis El-Manar, Faculté des Sciences de Tunis, Campus universitaire El-Manar, 1068 Tunis (Tunisia)

    2015-06-07

    Optical properties of polymerized cyclohexane films deposited by radiofrequency plasma enhanced chemical vapor deposition technique at different radiofrequency powers onto glass and silicon substrates, are studied and correlated with the microstructure of the films, using a combination of atomic force microscopy, Raman and Fourier Transformer Infrared spectroscopy and optical measurements. The optical constants such as refractive index n, dielectric permittivity ε and extinction k and absorption α coefficients, are extracted from transmission and reflection spectra through the commercial software CODE. These constants lead, by using common theoretical models as Cauchy, Lorentz, Tauc and single effective oscillator, to the determination of the static refractive index n{sub s} and permittivity ε{sub s}, the plasma frequency ω{sub p}, the carrier density to effective mass ratio N/m{sub e}{sup *}, the optical conductivity σ{sub oc}, the optical band gap E{sub g} and the oscillation and dispersion energies E{sub 0} and E{sub d}, respectively. We find that n, ε{sub s}, ω{sub p}, N/m{sub e}{sup *}, E{sub d}, increase with radiofrequency power, while E{sub g} and E{sub 0} decrease in the same range of power. These results are well correlated with those obtained from atomic force microscopy, Raman and infrared measurements. They also indicate that the increase of the radiofrequency power promotes the fragmentation of the precursor and increases the carbon C-sp{sup 2} hybridization proportion, which results in an improvement of the optoelectronic properties of the films.

  20. Three-Dimensional Polymeric Mechanical Metamaterials Fabricated by Multibeam Interference Lithography with the Assistance of Plasma Etching.

    Science.gov (United States)

    Kang, Da-Young; Lee, Wooju; Kim, Dongchoul; Moon, Jun Hyuk

    2016-08-23

    The pentamode structure is a type of mechanical metamaterial that displays dramatically different bulk and shear modulus responses. In this study, a face-centered cubic (FCC) polymeric microstructure was fabricated by using SU8 negative-type photoresists and multibeam interference exposure. Isotropic plasma etching is used to control the solid-volume fraction; for the first time, we obtained a structure with the minimum solid-volume fraction as low as 15% that still exhibited high structural integrity. Using this method, we reduced the width of atom-to-atom connections by up to 40 nm. We characterize the effect of the connection area on the anisotropy of the mechanical properties using simulations. Nanoindentation measurements were also conducted to evaluate the energy dissipation by varying the connection area. The Young's/shear modulus ratio is 5 times higher for the etched microstructure than that of the bulk SU8 materials. The use of interference lithography may enable the properties of microscale materials to be engineered for various applications, such as MEMS.

  1. Optical and Surface Characterization of Radio Frequency Plasma Polymerized 1-Isopropyl-4-Methyl-1,4-Cyclohexadiene Thin Films

    Directory of Open Access Journals (Sweden)

    Jakaria Ahmad

    2014-04-01

    Full Text Available Low pressure radio frequency plasma-assisted deposition of 1-isopropyl-4-methyl-1,4-cyclohexadiene thin films was investigated for different polymerization conditions. Transparent, environmentally stable and flexible, these organic films are promising candidates for organic photovoltaics (OPV and flexible electronics applications, where they can be used as encapsulating coatings and insulating interlayers. The effect of deposition RF power on optical properties of the films was limited, with all films being optically transparent, with refractive indices in a range of 1.57–1.58 at 500 nm. The optical band gap (Eg of ~3 eV fell into the insulating Eg region, decreasing for films fabricated at higher RF power. Independent of deposition conditions, the surfaces were smooth and defect-free, with uniformly distributed morphological features and average roughness between 0.30 nm (at 10 W and 0.21 nm (at 75 W. Films fabricated at higher deposition power displayed enhanced resistance to delamination and wear, and improved hardness, from 0.40 GPa for 10 W to 0.58 GPa for 75 W at a load of 700 μN. From an application perspective, it is therefore possible to tune the mechanical and morphological properties of these films without compromising their optical transparency or insulating property.

  2. Surface modification of Polymers by plasma polymerization techniques for tissue engineering

    OpenAIRE

    Francesch de Castro, Laia

    2008-01-01

    El treball que es presenta en aquesta tesi pretén contribuir al camp de la ciència de superfícies biològiques, amb el desenvolupament de superfícies adaptades amb cadenes lateral reactives per tal de unir covalentment biomolècul·les d'interès a la superfície.La polimerització assistida per plasma del recobriments actius és un mètode atractiu per tal d'obtenir cadenes laterals reactives, mitjançant pel·lícules nanomètriques amb densitats de grups funcionals adaptats. Sota control de les condic...

  3. Development of a new chemical sensor based on plasma polymerized polypyrrole films

    OpenAIRE

    2010-01-01

    La present tesis contribueix a donar una nova visió dins de l'àrea de modificació de superfícies, la qual implica la nanoestructuració de substrats fent servir la tècnica d'auto-assemblatge per a dipositar sobre aquests un polímer conductor mitjançant deposició química en fase vapor per plasma. L'ús de polímers conductors ha despertat un creixent interès en el desenvolupament de sensors químics per a l'anàlisi de gasos en aplicacions d'enginyeria electrònica. La contínua reducció de mida en a...

  4. Use of thin films obtained by plasma polymerization for grain protection and germination enhancement

    Directory of Open Access Journals (Sweden)

    Rodrigo A. M. Carvalho

    2005-12-01

    Full Text Available In this work, preliminary results of the use of hydrophobic thin films obtained by plasma deposition to protect grains and seeds are presented: grains coated by the films did not present biological degradation when stored in a saturated water vapor environment, but had their germination accelerated in the presence of water. A model that explains the difference of behavior of the films when exposed to water in vapor form or in liquid form, based on the formation of microchannels within the film that lead to water uptake in seeds, is presented. The model was successfully tested using quartz crystal measurements, which showed that the microchannels within the films can favor the adsorption and permeation of water when the films are immersed in water.

  5. Condensation Polymerization

    Indian Academy of Sciences (India)

    S Ramakrishnan

    2017-04-01

    The very idea that large polymer molecules can indeed existwas hotly debated during the early part of the 20th century.As highlighted by Sivaram in his articles on Carothersand Flory, Staudinger’s macromolecular hypothesis was finallyaccepted, and the study of polymers gained momentumbecause of the remarkable efforts of the these two individualswho laid down the foundations concerning the processes thatled to the formation of large polymer molecules, and to thosethat led to an understanding of many of their extraordinaryphysical properties. Condensation polymerizations, as thename suggests, utilizes bond-forming reactions that generatea small molecule condensate, which often needs to be continuouslyremoved to facilitate the formation of the polymer. Inthis article, I shall describe some of the essential principles ofcondensation polymerizations or more appropriately calledstep-growth polymerizations; and I will also describe someinteresting extensions that lead to the formation of polymernetworks and highly branched polymers.

  6. Scale-up of the Reversible Addition-Fragmentation Chain Transfer (RAFT Polymerization Using Continuous Flow Processing

    Directory of Open Access Journals (Sweden)

    Nenad Micic

    2014-01-01

    Full Text Available A controlled radical polymerization process using the Reversible Addition-Fragmentation Chain Transfer (RAFT approach was scaled up by a factor of 100 from a small laboratory scale of 5 mL to a preparative scale of 500 mL, using batch and continuous flow processing. The batch polymerizations were carried out in a series of different glass vessels, using either magnetic or overhead stirring, and different modes of heating: Microwave irradiation or conductive heating in an oil bath. The continuous process was conducted in a prototype tubular flow reactor, consisting of 6 mm ID stainless steel tubing, fitted with static mixers. Both reactor types were tested for polymerizations of the acid functional monomers acrylic acid and 2-acrylamido-2-methylpropane-1-sulfonic acid in water at 80 °C with reaction times of 30 to 40 min. By monitoring the temperature during the exothermic polymerization process, it was observed that the type and size of reactor had a significant influence on the temperature profile of the reaction.

  7. Supramolecular 1-D polymerization of DNA origami through a dynamic process at the 2-dimensionally confined air-water interface.

    Science.gov (United States)

    Yonamine, Yusuke; Cervantes-Salguero, Keitel; Minami, Kosuke; Kawamata, Ibuki; Nakanishi, Waka; Hill, Jonathan P; Murata, Satoshi; Ariga, Katsuhiko

    2016-05-14

    In this study, a Langmuir-Blodgett (LB) system has been utilized for the regulation of polymerization of a DNA origami structure at the air-water interface as a two-dimensionally confined medium, which enables dynamic condensation of DNA origami units through variation of the film area at the macroscopic level (ca. 10-100 cm(2)). DNA origami sheets were conjugated with a cationic lipid (dioctadecyldimethylammonium bromide, 2C18N(+)) by electrostatic interaction and the corresponding LB-film was prepared. By applying dynamic pressure variation through compression-expansion processes, the lipid-modified DNA origami sheets underwent anisotropic polymerization forming a one-dimensionally assembled belt-shaped structure of a high aspect ratio although the thickness of the polymerized DNA origami was maintained at the unimolecular level. This approach opens up a new field of mechanical induction of the self-assembly of DNA origami structures.

  8. Plasma Processes : Arc root dynamics in high power plasma torches – Evidence of chaotic behavior

    Indian Academy of Sciences (India)

    A K Das

    2000-11-01

    Although plasma torches have been commercially available for about 50 years, areas such as plasma gun design, process efficiency, reproducibility, plasma stability, torch lives etc. have remained mostly unattended. Recent torch developments have been focusing on the basic understanding of the plasma column and its dynamics inside the plasma torch, the interaction of plasma jet and the powders, the interaction of the plasma jet with surroundings and the impingement of the jet on the substrate. Two of the major causes of erratic and poor performance of a variety of thermal plasma processes are currently identified as the fluctuations arising out of the arc root movement on the electrodes inside the plasma torch and the fluid dynamic instabilities arising out of entrainment of the air into the plasma jet. This paper reviews the current state of understanding of these fluctuations as well as the dynamics of arc root movement in plasma torches. The work done at the author’s laboratory on studying the fluctuations in arc voltage, arc current, acoustic emissions and optical emissions are also presented. These fluctuations are observed to be chaotic and interrelated. Real time monitoring and controlling the arc instabilities through chaos characterization parameters can greatly contribute to the understanding of electrode erosion as well as improvement of plasma torch lifetime.

  9. Conductive polythiophene-like thin film synthesized using controlled plasma processes

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Long [Department of Advanced Materials Science and Engineering, Nu-SKKU Joint Institute for Plasma Nano Materials, Center for Advanced Plasma Surface Technology, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Jeong, Dong-Cheol [Department of Chemistry, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Chemical and Biological Defense Research Center, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Javid, Amjed [Department of Advanced Materials Science and Engineering, Nu-SKKU Joint Institute for Plasma Nano Materials, Center for Advanced Plasma Surface Technology, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Kim, Sanghoon [Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Nam, Jae-Do [Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Department of Polymer Science and Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Song, Changsik [Department of Chemistry, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Chemical and Biological Defense Research Center, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Han, Jeon Geon, E-mail: hanjg@skku.edu [Department of Advanced Materials Science and Engineering, Nu-SKKU Joint Institute for Plasma Nano Materials, Center for Advanced Plasma Surface Technology, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2015-07-31

    Transparent conductive polythiophene-like thin films were synthesized by a plasma polymerization technique using a middle range frequency (40 kHz). The effects of the variation of power and pressure on the chemical structure of the deposited film were investigated along with the effect of doping with iodine vapors on the conductivity of the films. Plasma polymerization is a low temperature process, provides deposition of thin polymer films on a wide variety of substrates, and has advantages due to non-involvement of any solvents. The chemical structure of the films was characterized using Fourier Transform Infrared Spectroscopy. The wetting properties of the films were studied using water contact angle measurements. The fragmentation of the thiophene monomer structure increased with increasing discharge power, implying that at low discharge power, the plasma phase was energy-deficient. The lower fragmentation of the monomer led to high retention of the monomer structure in the deposited films. Under various pressure conditions, the retention of the monomer structure was found to be similar as that of the deposited films. After doping with iodine vapor, a large conductivity enhancement, from 3.52 × 10{sup −6} to 2.3 × 10{sup −3} s/cm was observed. The results showed the retention of a monomer structure having conjugated bonds in the films, responsible for the enhanced conductivities. - Highlights: • Fabrication of conductive polythiophene-like films by plasma process • Transmittance more than 80% • 3 order conductivity enhancement with iodine doping • Retention of monomer structure responsible for better conductivities.

  10. Roles of extracellular polymeric substances in enhanced biological phosphorus removal process.

    Science.gov (United States)

    Li, Wen-Wei; Zhang, Hai-Ling; Sheng, Guo-Ping; Yu, Han-Qing

    2015-12-01

    Enhanced biological phosphorus removal (EBPR) process is known to mainly rely on the ability of phosphorus-accumulating organisms to take up, transform and store excess amount of phosphorus (P) inside the cells. However, recent studies have revealed considerable accumulation of P also in the extracellular polymeric substances (EPS) of sludge, implying a non-negligible role of EPS in P removal by EBPR sludge. However, the contribution of EPS to P uptake and the forms of accumulated extracellular P vary substantially in different studies, and the underlying mechanism of P transformation and transportation in EPS remains poorly understood. This review provides a new recognition into the P removal process in EBPR system by incorporating the role of EPS. It overviews on the characteristics of P accumulation in EPS, explores the mechanism of P transformation and transportation in EBPR sludge and EPS, summarizes the main influential factors for the P-accumulation properties of EPS, and discusses the remaining knowledge gaps and needed future efforts that may lead to better understanding and use of such an EPS role for maximizing P recovery from wastewater. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Synthesis and micowave characterization of conductive polyaniline prepared by continous polymerization process

    Science.gov (United States)

    Manaf, A.; Bimantoro, A.; Hafizah, M. AE; Andreas

    2017-07-01

    Results of synthesized polyaniline (PANi) prepared by a continuous polymerization process is reported. The purpose of this research is to obtain material absorber which maximum absorption. FTIR spectrum for synthesized PANi showed no double bond absorption peak at 3442 cm-1 which indicates the polymer chain was formed through repetition of single bonds. The results of the electrical conductivity measurement showed the value 17.5 μS/cm for synthesized PANI. The value increased dramatically to 3600, 1520 and 920 μS/cm after the addition of photonic acids of HClO4, H2SO4 and HCl respectively. Those values were obtained through sequences process. Results of particle size distribution confirmed that all synthesized PANi have nanoparticles. In addition, all synthesized PANi have shown electromagnetic wave absorbing properties in the frequency range 12-18 GHz. The best peak Reflection Loss (RL) values -10 dB (˜ 68 % absorption) and -25 dB (˜ 84 %) at 13 and 16.5 GHz respectively obtained on the PANi Emeraldine base (PANi-EB).

  12. Plasma Processes : Minimum dissipative relaxed states in toroidal plasmas

    Indian Academy of Sciences (India)

    R Bhattacharyya; M S Janaki; B Dasgupta

    2000-11-01

    Relaxation of toroidal discharges is described by the principle of minimum energy dissipation together with the constraint of conserved global helicity. The resulting Euler-Lagrange equation is solved in toroidal coordinates for an axisymmetric torus by expressing the solutions in terms of Chandrasekhar-Kendall (C-K) eigenfunctions analytically continued in the complex domain. The C-K eigenfunctions are obtained as hypergeometric functions that are solutions of scalar Helmholtz equation in toroidal coordinates in the large aspect-ratio approximation. Equilibria are constructed by assuming the current to vanish at the edge of plasma. For the = 0; = 0 ( and are the poloidal and toroidal mode numbers respectively) relaxed states, the magnetic field, current, (safety factor) and pressure profiles are calculated for a given value of aspect-ratio of the torus and for different values of the eigenvalue 0. The new feature of the present model is that solutions allow for both tokamak as well as RFP-like behaviour with increase in the values of 0, which is related directly to volt-sec in the experiment.

  13. Plasma Processes : Plasma sprayed alumina coatings for radiation detector development

    Indian Academy of Sciences (India)

    Mary Alex; V Balagi; K R Prasad; K P Sreekumar; P V Ananthapadmanabhan

    2000-11-01

    Conventional design of radiation detectors uses sintered ceramic insulating modules. The major drawback of these ceramic components is their inherent brittleness. Ion chambers, in which these ceramic spacers are replaced by metallic components with plasma spray coated alumina, have been developed in our Research Centre. These components act as thin spacers that have good mechanical strength as well as high electrical insulation and replace alumina insulators with the same dimensions. As a result, the design of the beam loss monitor ion chamber for CAT could be simplified by coating the outer surface of the HT electrode with alumina. One of the chambers developed for isotope calibrator for brachytherapy gamma sources has its outer aluminium electrode (60 mm dia × 220 mm long) coated with 250 thick alumina (97%) + titania (3%). In view of potential applications in neutron-sensitive ion chambers used in reactor control instrumentation, studies were carried out on alumina 100 to 500 thick coatings on copper, aluminium and SS components. The electrical insulation varied from 108 ohms to 1012 ohms for coating thicknesses above 200 . The porosity in the coating resulted in some fall in electrical insulation due to moisture absorption. An improvement could be achieved by providing the ceramic surface with moisture-repellent silicone oil coating. Irradiation at Apsara reactor core location showed that the coating on aluminium was found to be unaffected after exposure to 1017 nvt fluence.

  14. Silicoaluminates as “Support Activator” Systems in Olefin Polymerization Processes

    Directory of Open Access Journals (Sweden)

    Tomás Cuenca

    2010-02-01

    Full Text Available In this work we report the polymerization behaviour of natural clays (montmorillonites, MMT as activating supports. These materials have been modified by treatment with different aluminium compounds in order to obtain enriched aluminium clays and to modify the global Brönsted/Lewis acidity. As a consequence, the intrinsic structural properties of the starting materials have been changed. These changes were studied and these new materials used for ethylene polymerization using a zirconocene complex as catalyst. All the systems were shown to be active in ethylene polymerization. The catalyst activity and the dependence on acid strength and textural properties have been also studied. The behaviour of an artificial silica (SBA 15 modified with an aluminium compound to obtain a silicoaluminate has been studied, but no ethylene polymerization activity has been found yet.

  15. Process characteristics of fibre-laser-assisted plasma arc welding

    OpenAIRE

    Mahrle, A; SCHNICK, M; Rose, S; Demuth, C; Beyer, E.; Füssel, U

    2011-01-01

    Abstract Experimental and theoretical investigations on fibre-laser assisted plasma arc welding (LAPW) have been performed. Welding experiments were carried out on aluminium and steel sheets. In case of a highly focused laser beam and a separate arrangement of plasma torch and laser beam, high-speed video recordings of the plasma arc and corresponding measurements of the time-dependent arc voltage revealed differences in the process behaviour for both materials. In case of aluminium weldin...

  16. Laser initiation and decay processes in an organic vapor plasma

    Science.gov (United States)

    Ding, Guowen

    A large volume organic molecular plasma (hundreds of cm3) is created by a 193 nm laser ionizing an organic molecule, Tetrakis-(dimethylamino)-ethylene (TMAE). The plasma is found to be characterized by high electron density (10 13-1011cm-3), low electron temperature (~0.1 eV), fast creation (~10 ns) and rapid decaying (electron-ion recombination coefficient ~10-6 cm3/s). Fast Langmuir probe (LP) techniques are developed for diagnosing this plasma, including a novel probe design and fabrication, a fast detection system, sampling, indirect probe heating, electro-magnetic shielding and dummy probe techniques. Plasma physical processes regarding fast LP diagnostics for different time scales (t> and <100 ns) are studied. A theory for the correction due to a rapidly decaying plasma to LP measurements is developed. The mechanisms responsible for the plasma decay are studied, and a delayed ionization process is found to be important in interpreting the decay processes. It is also found that nitrogen can enhance the delayed emission of a TMAE Rydberg state from the TMAE plasma. This result strongly suggests that a long-lifetime highly-excited state is important in the TMAE plasma decay process. This result supports the delayed ionization mechanism. A model combining electron-ion recombination and delayed ionization processes is developed to calculate the delayed ionization lifetime.

  17. Use of cold plasma in food processing

    NARCIS (Netherlands)

    Mastwijk, H.C.; Nierop Groot, M.N.

    2010-01-01

    Application of cold plasma has been reported in agriculture, food, and bioscience literature as an effective, non-chemical, gas-phase disinfection agent that can be applied at moderate temperatures. The unusual thermodynamic properties of these gases are discussed with focus on nitrogen-based

  18. Removal of dye by carboxymethyl cellulose, acrylamide and graphene oxide via a free radical polymerization process.

    Science.gov (United States)

    Varaprasad, Kokkarachedu; Jayaramudu, Tippabattini; Sadiku, Emmanuel Rotimi

    2017-05-15

    Carboxymethyl cellulose has been used for the design of novel engineered hydrogels in order to obtain effective three-dimensional structures for industrial applications. In this work, dye removal carboxymethyl cellulose-acrylamide-graphene oxide (CMC-AM-GO) hydrogels were prepared by a free-radical polymerization method. The GO was developed by the modified Hummers method. The CMC-AM-GO and GO were characterized by FTIR, XRD and SEM. The swelling and swelling kinetics were calculated using gravimetric process. The kinetic parameter, swelling exponent values [n=0.59-0.7507] explained the fact that the CMC-AM-GO hydrogles have super Case II diffusion transport mechanism. CMCx-AM-GO (x=1-4) and CMC-AM hydrogels were used for removal of Acid Blue-133. The result explains that composite hydrogels significantly removed the acid blue when compared to the neat hydrogel. The maximum AB absorption (185.45mg/g) capacity was found in the case of CMC2-AM-GO hydrogel. Therefore, cellulose-based GO hydrogels can be termed as smart systems for the abstraction of dye in water purification applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Real-time measurements of crystallization processes in viscoelastic polymeric photonic crystals.

    Science.gov (United States)

    Snoswell, David R E; Finlayson, Chris E; Zhao, Qibin; Baumberg, Jeremy J

    2015-11-01

    We present a study of the dynamic shear ordering of viscoelastic photonic crystals, based on core-shell polymeric composite particles. Using an adapted shear-cell arrangement, the crystalline ordering of the material under conditions of oscillatory shear is interrogated in real time, through both video imaging and from the optical transmission spectra of the cell. In order to gain a deeper understanding of the macroscopic influences of shear on the crystallization process in this solvent-free system, the development of bulk ordering is studied as a function of the key parameters including duty cycle and shear-strain magnitude. In particular, optimal ordering is observed from a prerandomized sample at shear strains of around 160%, for 1-Hz oscillations. This ordering reaches completion over time scales of order 10 s. These observations suggest significant local strains are needed to drive nanoparticles through energy barriers, and that local creep is needed to break temporal symmetry in such high-viscosity nanoassemblies. Crystal shear-melting effects are also characterized under conditions of constant shear rate. These quantitative experiments aim to stimulate the development of theoretical models which can deal with the strong local particle interactions in this system.

  20. Low band gap polymeric solar cells using solution-processable copper iodide as hole transporting layer

    Science.gov (United States)

    Chaudhary, Neeraj; Kesari, J. P.; Chaudhary, Rajiv; Patra, Asit

    2016-08-01

    In the present work, we have shown the performance of solution-processable copper iodide (CuI) as an alternative hole transporting layer (HTL) for polymeric solar cells. Optical spectra of the CuI thin film reveal highly transparent and practically no absorption in the range vis-NIR region (450-1110 nm). X-ray diffraction (XRD) patterns of CuI exhibits as a p-type semiconductor as well as crystalline nature. The photovoltaic devices were fabricated using PCDTBT and PTB7 as donor materials blended with PC71BM as an acceptor material. The power conversion efficiencies (PCEs) based on CuI as an HTL have been achieved to up to 3.04% and 4.48% for PCDTBT and PTB7 based donor materials respectively with a configuration based on ITO/CuI(40 nm)/active layer (60 nm)/Al (120 nm). This study clearly indicated that the devices made with CuI as an HTL showed superior performance than the device fabricated from PEDOT:PSS layer as an HTL. Morphological characterization of the HTL using scanning electron microscopy (SEM) and atomic force microscope (AFM) were carried for better understanding.

  1. Plasma processing methods for hydrogen production

    Science.gov (United States)

    Mizeraczyk, Jerzy; Jasiński, Mariusz

    2016-08-01

    In the future a transfer from the fossil fuel-based economy to hydrogen-based economy is expected. Therefore the development of systems for efficient H2 production becomes important. The several conventional methods of mass-scale (or central) H2 production (methane, natural gas and higher hydrocarbons reforming, coal gasification reforming) are well developed and their costs of H2 production are acceptable. However, due to the H2 transport and storage problems the small-scale (distributed) technologies for H2 production are demanded. However, these new technologies have to meet the requirement of producing H2 at a production cost of (1-2)/kg(H2) (or 60 g(H2)/kWh) by 2020 (the U.S. Department of Energy's target). Recently several plasma methods have been proposed for the small-scale H2 production. The most promising plasmas for this purpose seems to be those generated by gliding, plasmatron and nozzle arcs, and microwave discharges. In this paper plasma methods proposed for H2 production are briefly described and critically evaluated from the view point of H2 production efficiency. The paper is aiming at answering a question if any plasma method for the small-scale H2 production approaches such challenges as the production energy yield of 60 g(H2)/kWh, high production rate, high reliability and low investment cost. Contribution to the topical issue "6th Central European Symposium on Plasma Chemistry (CESPC-6)", edited by Nicolas Gherardi, Ester Marotta and Cristina Paradisi

  2. Synthesis of functional nanocrystallites through reactive thermal plasma processing

    Directory of Open Access Journals (Sweden)

    Takamasa Ishigaki and Ji-Guang Li

    2007-01-01

    Full Text Available A method of synthesizing functional nanostructured powders through reactive thermal plasma processing has been developed. The synthesis of nanosized titanium oxide powders was performed by the oxidation of solid and liquid precursors. Quench gases, either injected from the shoulder of the reactor or injected counter to the plasma plume from the bottom of the reactor, were used to vary the quench rate, and therefore the particle size, of the resultant powders. The experimental results are well supported by numerical analysis on the effects of the quench gas on the flow pattern and temperature field of the thermal plasma as well as on the trajectory and temperature history of the particles. The plasma-synthesized TiO2 nanoparticles showed phase preferences different from those synthesized by conventional wet-chemical processes. Nanosized particles of high crystallinity and nonequilibrium chemical composition were formed in one step via reactive thermal plasma processing.

  3. Study of polymerization of acrylamide initiated by atmospheric pressure plasma%常压等离子体引发丙烯酰胺聚合研究

    Institute of Scientific and Technical Information of China (English)

    余冬冬; 王明洋; 王升高

    2011-01-01

    In this study, super absorbent polyacrylamide was prepared by the cold are Ar plasma which initiated polymerization of Acrylamide.The effects of the discharge time, the polymerization temperature and the monomer concentration on the absorption of the polymer were studied.Result showed that the absorption of the polymer is 340(g/g) under the conditions of the 90 s discharge time,the 30 ℃ polymerization temperature, the 30% monomer concentration and the 24 h polymerization time.%利用Ar冷弧等离子体对丙烯酰胺单体进行处理并引发聚合,制备出高吸水性聚丙烯酰胺.研究了放电时间、聚合温度、单体质量分数等对聚合产物吸水性能的影响,实验结果表明在放电时间为90 s,聚合温度为30℃,单体质量分数为30%,后聚合时间为24 h的聚合条件下聚合物的吸水率为340(g/g).

  4. Mirror-field confined compact plasma source using permanent magnet for plasma processings

    Science.gov (United States)

    Goto, Tetsuya; Sato, Kei-ichiro; Yabuta, Yuki; Sugawa, Shigetoshi

    2016-12-01

    A mirror-field confined compact electron cyclotron resonance (ECR) plasma source using permanent magnets was developed, aiming for the realization of high-quality plasma processings where high-density reactive species are supplied to a substrate with minimizing the ion bombardment damages. The ECR position was located between a microwave transmissive window and a quartz limiter, and plasmas were transported from the ECR position to a midplane of the magnetic mirror field through the quartz limiter. Thus, a radius of core plasma could be determined by the limiter, which was 15 mm in this study. Plasma parameters were investigated by the Langmuir probe measurement. High-density plasma larger than 1011 cm-3 could be produced by applying 5.85-GHz microwave power of 10 W or more. For the outside region of the core plasma where a wafer for plasma processings will be set at, the ion current density was decreased dramatically with distance from the core plasma and became smaller by approximately two orders of magnitude that in the core plasma region for the radial position of 40 mm, suggesting the realization of reduction in ion bombardment damages.

  5. Mirror-field confined compact plasma source using permanent magnet for plasma processings.

    Science.gov (United States)

    Goto, Tetsuya; Sato, Kei-Ichiro; Yabuta, Yuki; Sugawa, Shigetoshi

    2016-12-01

    A mirror-field confined compact electron cyclotron resonance (ECR) plasma source using permanent magnets was developed, aiming for the realization of high-quality plasma processings where high-density reactive species are supplied to a substrate with minimizing the ion bombardment damages. The ECR position was located between a microwave transmissive window and a quartz limiter, and plasmas were transported from the ECR position to a midplane of the magnetic mirror field through the quartz limiter. Thus, a radius of core plasma could be determined by the limiter, which was 15 mm in this study. Plasma parameters were investigated by the Langmuir probe measurement. High-density plasma larger than 10(11) cm(-3) could be produced by applying 5.85-GHz microwave power of 10 W or more. For the outside region of the core plasma where a wafer for plasma processings will be set at, the ion current density was decreased dramatically with distance from the core plasma and became smaller by approximately two orders of magnitude that in the core plasma region for the radial position of 40 mm, suggesting the realization of reduction in ion bombardment damages.

  6. Plasma Processing with Fluorine Chemistry for Modification of Surfaces Wettability

    Directory of Open Access Journals (Sweden)

    Veronica Satulu

    2016-12-01

    Full Text Available Using plasma in conjunction with fluorinated compounds is widely encountered in material processing. We discuss several plasma techniques for surface fluorination: deposition of fluorocarbon thin films either by magnetron sputtering of polytetrafluoroethylene targets, or by plasma-assisted chemical vapor deposition using tetrafluoroethane as a precursor, and modification of carbon nanowalls by plasma treatment in a sulphur hexafluoride environment. We showed that conformal fluorinated thin films can be obtained and, according to the initial surface properties, superhydrophobic surfaces can be achieved.

  7. Soft-Sensor Modeling of PVC Polymerizing Process Based on F-GMDH-Type Neural Network Algorithm

    Directory of Open Access Journals (Sweden)

    Wei-zhen Sun

    2017-01-01

    Full Text Available For predicting the conversion velocity of the vinyl chloride monomer (VCM in the polymerization process of polyvinylchloride (PVC, an improved Group Method of Data Handling- (GMDH- type neural network soft-sensor model is proposed. After analyzing the technique of PVC manufacturing process, the auxiliary variables for setting up the soft-sensor model are selected and the experimental data are normalized. Because the internal standard of the original GMDH-type neural cannot solve the problem of multiple-collinearity problem and the useful variables tend to be prematurely eliminated in the modeling process, a hybrid method combining the regression analysis method and the least squares method is proposed to solve the multiple-collinearity problem. On the same time, by adopting some optimization experiences in genetic algorithm (GA, the generational crossover combination variables method is proposed to solve the shortcoming of useful variable being eliminated prematurely. The simulation results show that the proposed soft-sensor model can significantly improve the prediction accuracy of economic and technical indicators in the PVC polymerization process and can meet the real time control requirements of polymerization reactor production process.

  8. 变温聚合工艺对聚合反应速率及PVC树脂性能的影响%The influence of heterothermal polymerization process on the polymerization rate and characteristics of the suspension PVC

    Institute of Scientific and Technical Information of China (English)

    梁斌; 张磊; 于永玲; 鲍春伟; 车万里; 张学明

    2013-01-01

    分别采用恒温和变温聚合工艺合成聚氯乙烯(PVC)树脂,研究了PVC树脂的基本性能.结果表明:采用变温聚合工艺,在压力下降阶段提高聚合温度制备PVC树脂,可提高聚合反应速率,树脂热稳定性和颗粒性能合格.与恒温聚合工艺所制树脂相比,变温聚合工艺所制PVC树脂的聚合度下降约40,相对分子质量分布由2.05增至2.15,热稳定性略有提高;较宽的相对分子质量分布改善了树脂的加工性能,据此优化加工配方可使制品保持良好的力学性能.%Two poly(vinyl chloride) (PVC) resin samples were synthesized via isothermal polymerization process and heterothermal polymerization process, respectively, and the resin properties were studied. The results show that the polymerization rate can increase by raising polymerization temperature during period of the pressure drop, and thermal stability and grain properties of the produced PVC are qualified. In comparison with the PVC resin prepared by isothermal polymerization process, the PVC resin obtained by heterothermal polymerization process has average polymerization degree decreased about 40, the relative molecular mass distribution of the latter increases to 2.15 from 2.05 of the former, and the thermal stability of the latter improves slightly. The processability of the resins so produced is improved owing to its wider relative molecular mass distribution, in the light of which the product can maintain excellent mechanical property by optimizing processing formulation.

  9. Fluorophore-based sensor for oxygen radicals in processing plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Choudhury, Faraz A.; Shohet, J. Leon, E-mail: shohet@engr.wisc.edu [Plasma Processing and Technology Laboratory and Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Sabat, Grzegorz; Sussman, Michael R. [Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Nishi, Yoshio [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)

    2015-11-15

    A high concentration of radicals is present in many processing plasmas, which affects the processing conditions and the properties of materials exposed to the plasma. Determining the types and concentrations of free radicals present in the plasma is critical in order to determine their effects on the materials being processed. Current methods for detecting free radicals in a plasma require multiple expensive and bulky instruments, complex setups, and often, modifications to the plasma reactor. This work presents a simple technique that detects reactive-oxygen radicals incident on a surface from a plasma. The measurements are made using a fluorophore dye that is commonly used in biological and cellular systems for assay labeling in liquids. Using fluorometric analysis, it was found that the fluorophore reacts with oxygen radicals incident from the plasma, which is indicated by degradation of its fluorescence. As plasma power was increased, the quenching of the fluorescence significantly increased. Both immobilized and nonimmobilized fluorophore dyes were used and the results indicate that both states function effectively under vacuum conditions. The reaction mechanism is very similar to that of the liquid dye.

  10. Method and system for nanoscale plasma processing of objects

    Science.gov (United States)

    Oehrlein, Gottlieb S.; Hua, Xuefeng; Stolz, Christian

    2008-12-30

    A plasma processing system includes a source of plasma, a substrate and a shutter positioned in close proximity to the substrate. The substrate/shutter relative disposition is changed for precise control of substrate/plasma interaction. This way, the substrate interacts only with a fully established, stable plasma for short times required for nanoscale processing of materials. The shutter includes an opening of a predetermined width, and preferably is patterned to form an array of slits with dimensions that are smaller than the Debye screening length. This enables control of the substrate/plasma interaction time while avoiding the ion bombardment of the substrate in an undesirable fashion. The relative disposition between the shutter and the substrate can be made either by moving the shutter or by moving the substrate.

  11. Apparatus and method for plasma processing of SRF cavities

    CERN Document Server

    Upadhyay, J; Peshl, J; Bašović, M; Popović, S; Valente-Feliciano, A -M; Phillips, L; Vuškovića, L

    2015-01-01

    An apparatus and a method are described for plasma etching of the inner surface of superconducting radio frequency (SRF) cavities. Accelerator SRF cavities are formed into a variable-diameter cylindrical structure made of bulk niobium, for resonant generation of the particle accelerating field. The etch rate non-uniformity due to depletion of the radicals has been overcome by the simultaneous movement of the gas flow inlet and the inner electrode. An effective shape of the inner electrode to reduce the plasma asymmetry for the coaxial cylindrical rf plasma reactor is determined and implemented in the cavity processing method. The processing was accomplished by moving axially the inner electrode and the gas flow inlet in a step-wise way to establish segmented plasma columns. The test structure was a pillbox cavity made of steel of similar dimension to the standard SRF cavity. This was adopted to experimentally verify the plasma surface reaction on cylindrical structures with variable diameter using the segment...

  12. Status and challenges in electrical diagnostics of processing plasmas

    DEFF Research Database (Denmark)

    Stamate, Eugen

    Reactive plasmas produced in oxygen, nitrogen, hydrogen and other complex gas mixture are used for various applications including thin films, etching, ion implantation, ashing, particles growth, oxidation and other surface functionalization processes. Most of the reactive gases are also...... the possibility to control and use these plasmas for processing. Development of reactive plasma sources for both applications and basic science is rather challenging and some of these efforts will be presented in direct correlation with diagnostic approaches....... electronegative so that, the role of negative ions cannot be neglected. The continuous decrease of the features size in micro- and nanoelectronic industry requires a precise control of plasma parameters including the negative ions. Despite of a good progress in plasma diagnostics, yet more is to be done...

  13. Radiant-and-plasma technology for coal processing

    Directory of Open Access Journals (Sweden)

    Vladimir Messerle

    2012-12-01

    Full Text Available Radiant-and-plasma technology for coal processing is presented in the article. Thermodynamic computation and experiments on plasma processing of bituminous coal preliminary electron-beam activated were fulfilled in comparison with plasma processing of the coal. Positive influence of the preliminary electron-beam activation of coal on synthesis gas yield was found. Experiments were carried out in the plasma gasifier of 100 kW power. As a result of the measurements of material and heat balance of the process gave the following integral indicators: weight-average temperature of 2200-2300 K, and carbon gasification degree of 82,4-83,2%. Synthesis gas yield at thermochemical preparation of raw coal dust for burning was 24,5% and in the case of electron-beam activation of coal synthesis gas yield reached 36,4%, which is 48% higher.

  14. SOME COLLISION PROCESSES IN PLASMAS WITH HIGHER TEMPERATURE AND DENSITY

    Institute of Scientific and Technical Information of China (English)

    KazuoTakayanagi

    1990-01-01

    Some collision processes important in hot and dense plasmas are discussed.Recent calculation of secondary electron velocity distribution in ionizing collision between an electron and a multiply-charged ion is reported.

  15. Reactive Atom Plasma Processing of Slumped Glass Wedges Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Reactive Atom Plasma (RAPTM) process will be evaluated as a rapid and practical method for fabricating precision wedges in glass sheets. The glass sheets are to...

  16. Surface Modification of Fillers and Curatives by Plasma Polymerization for Enhanced Performance of Single Rubbers and Dissimilar Rubber/Rubber Blends

    Science.gov (United States)

    Noordermeer, J. W. M.; Datta, R. N.; Dierkes, W. K.; Guo, R.; Mathew, T.; Talma, A. G.; Tiwari, M.; van Ooij, W.

    Plasma polymerization is a technique for modifying the surface characteristics of fillers and curatives for rubber from essentially polar to nonpolar. Acetylene, thiophene, and pyrrole are employed to modify silica and carbon black reinforcing fillers. Silica is easy to modify because its surface contains siloxane and silanol species. On carbon black, only a limited amount of plasma deposition takes place, due to its nonreactive nature. Oxidized gas blacks, with larger oxygen functionality, and particularly carbon black left over from fullerene production, show substantial plasma deposition. Also, carbon/silica dual-phase fillers react well because the silica content is reactive. Elemental sulfur, the well-known vulcanization agent for rubbers, can also be modified reasonably well.

  17. Development of Expert Controller for Plasma Spraying Process

    Institute of Scientific and Technical Information of China (English)

    LIChun-xu; CHENKe-xuan; LIHe-qi; LIDe-wu

    2004-01-01

    Aiming at the plasma spraying process control, the control system model is developed on the basis of analyzing control parameters and coating properties and their correlation, and the corresponding control method and regulations are also given. With the developed expert controller for plasma spraying process, stable spraying can be realized using ordinary spraying powder and the coating of compaction, homogeneity and high bonding strength can be obtained.

  18. Time dependent atomic processes in discharge produced low Z plasma

    Science.gov (United States)

    Yuyama, M.; Sasaki, T.; Horioka, K.; Kawamura, T.

    2008-05-01

    The z-pinch simulation have been performed with magneto-hydro dynamics and atomic population kinetics codes. A factor associated with transient atomic processes was proposed. The atomic transient degrees of dopant lithium in hydrogen plasma were calculated with initial plasma densities of 1.0 × 1016 ~ 5.0 × 1017cm-3. The higher initial plasma density is, the lower is the transient degree generally. It is also found that the transient properties of the atomic processes are sensitive to ionization energy and electron temperature.

  19. Initial damage processes for diamond film exposure to hydrogen plasma

    Energy Technology Data Exchange (ETDEWEB)

    Deslandes, A., E-mail: acd@ansto.gov.au [Institute for Environmental Research, Australian Nuclear Science and Technology Organisation, Sydney (Australia); Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Sydney (Australia); Guenette, M.C. [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Sydney (Australia); Samuell, C.M. [Plasma Research Laboratory, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Karatchevtseva, I. [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Sydney (Australia); Ionescu, M.; Cohen, D.D. [Institute for Environmental Research, Australian Nuclear Science and Technology Organisation, Sydney (Australia); Blackwell, B. [Plasma Research Laboratory, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Corr, C., E-mail: cormac.corr@anu.edu.au [Plasma Research Laboratory, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Riley, D.P., E-mail: dry@ansto.gov.au [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Sydney (Australia)

    2013-12-15

    Graphical abstract: -- Highlights: • Exposing chemical vapour deposited (CVD) diamond films in a recently constructed device, MAGPIE, specially commissioned to simulate fusion plasma conditions. • Non-diamond material is etched from the diamond. • There is no hydrogen retention observed, which suggests diamond is an excellent candidate for plasma facing materials. • Final structure of the surface is dependent on synergistic effects of etching and ion-induced structural change. -- Abstract: Diamond is considered to be a possible alternative to other carbon based materials as a plasma facing material in nuclear fusion devices due to its high thermal conductivity and resistance to chemical erosion. In this work CVD diamond films were exposed to hydrogen plasma in the MAGnetized Plasma Interaction Experiment (MAGPIE): a linear plasma device at the Australian National University which simulates plasma conditions relevant to nuclear fusion. Various negative sample stage biases of magnitude less than 500 V were applied to control the energies of impinging ions. Characterisation results from SEM, Raman spectroscopy and ERDA are presented. No measureable quantity of hydrogen retention was observed, this is either due to no incorporation of hydrogen into the diamond structure or due to initial incorporation as a hydrocarbon followed by subsequent etching back into the plasma. A model is presented for the initial stages of diamond erosion in fusion relevant hydrogen plasma that involves chemical erosion of non-diamond material from the surface by hydrogen radicals and damage to the subsurface region from energetic hydrogen ions. These results show that the initial damage processes in this plasma regime are comparable to previous studies of the fundamental processes as reported for less extreme plasma such as in the development of diamond films.

  20. Real-Time Fault Classification for Plasma Processes

    Directory of Open Access Journals (Sweden)

    Ryan Yang

    2011-07-01

    Full Text Available Plasma process tools, which usually cost several millions of US dollars, are often used in the semiconductor fabrication etching process. If the plasma process is halted due to some process fault, the productivity will be reduced and the cost will increase. In order to maximize the product/wafer yield and tool productivity, a timely and effective fault process detection is required in a plasma reactor. The classification of fault events can help the users to quickly identify fault processes, and thus can save downtime of the plasma tool. In this work, optical emission spectroscopy (OES is employed as the metrology sensor for in-situ process monitoring. Splitting into twelve different match rates by spectrum bands, the matching rate indicator in our previous work (Yang, R.; Chen, R.S. Sensors 2010, 10, 5703-5723 is used to detect the fault process. Based on the match data, a real-time classification of plasma faults is achieved by a novel method, developed in this study. Experiments were conducted to validate the novel fault classification. From the experimental results, we may conclude that the proposed method is feasible inasmuch that the overall accuracy rate of the classification for fault event shifts is 27 out of 28 or about 96.4% in success.

  1. Real-time fault classification for plasma processes.

    Science.gov (United States)

    Yang, Ryan; Chen, Rongshun

    2011-01-01

    Plasma process tools, which usually cost several millions of US dollars, are often used in the semiconductor fabrication etching process. If the plasma process is halted due to some process fault, the productivity will be reduced and the cost will increase. In order to maximize the product/wafer yield and tool productivity, a timely and effective fault process detection is required in a plasma reactor. The classification of fault events can help the users to quickly identify fault processes, and thus can save downtime of the plasma tool. In this work, optical emission spectroscopy (OES) is employed as the metrology sensor for in-situ process monitoring. Splitting into twelve different match rates by spectrum bands, the matching rate indicator in our previous work (Yang, R.; Chen, R.S. Sensors 2010, 10, 5703-5723) is used to detect the fault process. Based on the match data, a real-time classification of plasma faults is achieved by a novel method, developed in this study. Experiments were conducted to validate the novel fault classification. From the experimental results, we may conclude that the proposed method is feasible inasmuch that the overall accuracy rate of the classification for fault event shifts is 27 out of 28 or about 96.4% in success.

  2. Proceedings of the international seminar on atomic processes in plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Takako; Murakami, Izumi [eds.

    2000-01-01

    The International Seminar on Atomic Processes in Plasmas (ISAPP), a satellite meeting to the ICPEAC was held July 28-29 at the National Institute for Fusion Science in Toki, Gifu, Japan. About 110 scientists attended the ISAPP meeting and discussed atomic processes and atomic data required for fusion research. This Proceedings book includes the papers of the talks, posters and panel discussion given at the meeting. The invited talks described the super configuration array method for complex spectra, near-LTE atomic kinetics, R-matrix calculations, the binary-encounter dipole model for electron-impact ionization of molecules, other calculations of molecular processes, the ADAS project and the NIFS atomic data-base, and a survey of the role of molecular processes in divertor plasmas. On the experimental side crossed-beam ion-ion collision-experiments for charge transfer, and storage-ring and EBIT measurements of ionization, excitation and dielectronic recombination cross-sections were presented, and atomic processes important for x-ray laser experiments and x-ray spectroscopy of astrophysical plasmas were described. The new method of plasma polarization spectroscopy was outlined. There was also a spectroscopic study of particle transport in JT-60U, new results for detached plasmas, and a sketch of the first hot plasma experiments with the Large Helical Device recently completed at NIFS. The 63 of the presented papers are indexed individually. (J.P.N.)

  3. Study on the ignition process of a segmented plasma torch

    Science.gov (United States)

    Cao, Xiuquan; Yu, Deping; Xiang, Yong; Li, Chao; Jiang, Hui; Yao, Jin

    2017-07-01

    Direct current plasma torches have been applied to generate unique sources of thermal energy in many industrial applications. Nevertheless, the successful ignition of a plasma torch is the key process to generate the unique source (plasma jet). However, there has been little study on the underlying mechanism of this key process. A thorough understanding of the ignition process of a plasma torch will be helpful for optimizing the design of the plasma torch structure and selection of the ignition parameters to prolong the service life of the ignition module. Thus, in this paper, the ignition process of a segmented plasma torch (SPT) is theoretically and experimentally modeled and analyzed. Corresponding electrical models of different stages of the ignition process are set up and used to derive the electrical parameters, e.g. the variations of the arc voltage and arc current between the cathode and anode. In addition, the experiments with different ignition parameters on a home-made SPT have been conducted. At the same time, the variations of the arc voltage and arc current have been measured, and used to verify the ones derived in theory and to determine the optimal ignition parameters for a particular SPT.

  4. Spectroscopic diagnostics of plasma during laser processing of aluminium

    Science.gov (United States)

    Lober, R.; Mazumder, J.

    2007-10-01

    The role of the plasma in laser-metal interaction is of considerable interest due to its influence in the energy transfer mechanism in industrial laser materials processing. A 10 kW CO2 laser was used to study its interaction with aluminium under an argon environment. The objective was to determine the absorption and refraction of the laser beam through the plasma during the processing of aluminium. Laser processing of aluminium is becoming an important topic for many industries, including the automobile industry. The spectroscopic relative line to continuum method was used to determine the electron temperature distribution within the plasma by investigating the 4158 Å Ar I line emission and the continuum adjacent to it. The plasmas are induced in 1.0 atm pure Ar environment over a translating Al target, using f/7 and 10 kW CO2 laser. Spectroscopic data indicated that the plasma composition and behaviour were Ar-dominated. Experimental results indicated the plasma core temperature to be 14 000-15 300 K over the incident range of laser powers investigated from 5 to 7 kW. It was found that 7.5-29% of the incident laser power was absorbed by the plasma. Cross-section analysis of the melt pools from the Al samples revealed the absence of any key-hole formation and confirmed that the energy transfer mechanism in the targets was conduction dominated for the reported range of experimental data.

  5. Atmospheric pressure plasmas for aerosols processes in materials and environment

    Science.gov (United States)

    Borra, J. P.; Jidenko, N.; Bourgeois, E.

    2009-08-01

    The paper highlights applications of some atmospheric pressure plasmas (dc-corona, streamer and spark and ac-Dielectric Barrier Discharges) to aerosol processes for Materials and Environment (filtration, diagnostics). The production of vapor i.e. condensable gaseous species, leads to nano-sized particles by physical and chemical routes of nucleation in these AP plasmas: (i) when dc streamer and spark filamentary discharges as well as ac filamentary dielectric barrier discharges interact with metal or dielectric surfaces, and (ii) when discharges induce reactions with gaseous precursors in volume. It is shown how composition, size and structure of primary nano-particles are related to plasma parameters (energy, number per unit surface and time and thermal gradients). Then the growth by coagulation controls the final size of agglomerates versus plasma parameters and transit time in and after the plasma. Charging and electro-thermal collection are depicted to account for the related potential applications of controlled kinematics of charged aerosol.

  6. Single kaolinite nanometer layers prepared by an in situ polymerization-exfoliation process in the presence of ionic liquids.

    Science.gov (United States)

    Letaief, Sadok; Leclercq, Jérôme; Liu, Yun; Detellier, Christian

    2011-12-20

    A simple chemical route for the exfoliation of kaolinite in the presence of polymerizable ionic liquids and the resulting obtainment of exfoliated nanocomposites is reported. The exfoliation was achieved using three different ionic liquids structurally bearing a vinyl group: 1-methyl-3-(4-vinylbenzyl)imidazolium chloride salt (IL_1), 1-methyl-1-(4-vinylbenzyl)pyrrolidinium chloride (IL_2), and 1-methyl-3-vinyl imidazolium iodide (IL_3) and a urea-kaolinite intercalate as precursor. The reaction was done in one step by an in situ polymerization-exfoliation process. (13)C CP/MAS NMR spectra confirmed the spontaneous polymerization of the ionic liquid during the exfoliation process to afford atactic polystyrene derivatives in the case of IL_1 and IL_2. The amount of organic material in the exfoliated nanocomposite was close to 30% as shown by thermal gravimetric analysis. This amount is small in comparison to the amount obtained when the exfoliation was done using sodium polyacrylate (Letaief and Detellier, Langmuir2009, 25, 10975). XRD as well as SEM analysis confirmed a total exfoliation of the kaolinite when the reaction was done using urea kaolinite, whereas a microcomposite, made predominantly of kaolinite platelet aggregates dispersed in the polymeric matrix, was formed when dimethylsulfoxide kaolinite was used as the precursor.

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

    Science.gov (United States)

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

    2015-01-01

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

  8. Linear and Nonlinear MHD Wave Processes in Plasmas. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Tataronis, J. A.

    2004-06-01

    This program treats theoretically low frequency linear and nonlinear wave processes in magnetized plasmas. A primary objective has been to evaluate the effectiveness of MHD waves to heat plasma and drive current in toroidal configurations. The research covers the following topics: (1) the existence and properties of the MHD continua in plasma equilibria without spatial symmetry; (2) low frequency nonresonant current drive and nonlinear Alfven wave effects; and (3) nonlinear electron acceleration by rf and random plasma waves. Results have contributed to the fundamental knowledge base of MHD activity in symmetric and asymmetric toroidal plasmas. Among the accomplishments of this research effort, the following are highlighted: Identification of the MHD continuum mode singularities in toroidal geometry. Derivation of a third order ordinary differential equation that governs nonlinear current drive in the singular layers of the Alfvkn continuum modes in axisymmetric toroidal geometry. Bounded solutions of this ODE implies a net average current parallel to the toroidal equilibrium magnetic field. Discovery of a new unstable continuum of the linearized MHD equation in axially periodic circular plasma cylinders with shear and incompressibility. This continuum, which we named “accumulation continuum” and which is related to ballooning modes, arises as discrete unstable eigenfrequency accumulate on the imaginary frequency axis in the limit of large mode numbers. Development of techniques to control nonlinear electron acceleration through the action of multiple coherent and random plasmas waves. Two important elements of this program aye student participation and student training in plasma theory.

  9. Plasma Processing of Large Curved Surfaces for SRF Cavity Modification

    CERN Document Server

    Upadhyay, J; Popović, S; Valente-Feliciano, A -M; Phillips, L; Vušković, L

    2014-01-01

    Plasma based surface modification of niobium is a promising alternative to wet etching of superconducting radio frequency (SRF) cavities. The development of the technology based on Cl2/Ar plasma etching has to address several crucial parameters which influence the etching rate and surface roughness, and eventually, determine cavity performance. This includes dependence of the process on the frequency of the RF generator, gas pressure, power level, the driven (inner) electrode configuration, and the chlorine concentration in the gas mixture during plasma processing. To demonstrate surface layer removal in the asymmetric non-planar geometry, we are using a simple cylindrical cavity with 8 ports symmetrically distributed over the cylinder. The ports are used for diagnosing the plasma parameters and as holders for the samples to be etched. The etching rate is highly correlated with the shape of the inner electrode, radio-frequency (RF) circuit elements, chlorine concentration in the Cl2/Ar gas mixtures, residence...

  10. Thrombin interaction with fibrin polymerization sites.

    Science.gov (United States)

    Hsieh, K

    1997-05-15

    Thrombin is central to hemostasis, and postclotting fibrinolysis and wound healing. During clotting, thrombin transforms plasma fibrinogen into polymerizing fibrin, which selectively adsorbs the enzyme into the clot. This protects thrombin from heparin-antithrombin inactivation, thus preserving the enzyme for postclotting events. To determine how the fibrin N-terminal polymerization sites of A alpha 17-23 (GPRVVER) and B beta 15-25 (GHRPLDKKREE) and their analogs may interact with thrombin, amidolysis vs. plasma- and fibrinogen-clotting assays were used to differentiate blockade of catalytic site vs. other thrombin domains. Amidolysis studies suggest GPRVVER inhibition of thrombin catalytic site through hydrophobic interaction, and GPRVVER inhibited clotting. Neither GPRP nor VVER nor the B beta 15-25 homologs inhibited amidolysis. Contrary to heparin, acyl-DKKREE promoted plasma-clotting, but inhibited fibrinogen-clotting. In addition, acyl-DKKREE reversed the anticoagulant effect of heparin (0.1 U/ml) in plasma. The results suggest fibrin B beta 15-25 interaction with thrombin, possibly by blocking the heparin-binding site. Together with the reported fibrin A alpha 27-50 binding to thrombin, polymerizing fibrin appears to initially bind to thrombin catalytic site and exosite-1 through A alpha 17-50, and to another thrombin site through B beta 15-25. As these fibrin sites are also involved in polymerization, competition of the polymerization process with thrombin-binding could subsequently dislodge thrombin from fibrin alpha-chain. This may re-expose the catalytic site and exosite-1, thus explaining the thrombogenicity of clot-bound thrombin. The implications of these findings in polymerization mechanism and anticoagulant design are discussed.

  11. Modelling of the arc reattachment process in plasma torches

    Energy Technology Data Exchange (ETDEWEB)

    Trelles, J P; Pfender, E; Heberlein, J V R [Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455 (United States)

    2007-09-21

    The need to improve plasma spraying processes has motivated the development of computational models capable of describing the arc dynamics inside plasma torches. Although progress has been made in the development of such models, the realistic simulation of the arc reattachment process, a central part of the arc dynamics inside plasma torches, is still an unsolved problem. This study presents a reattachment model capable of mimicking the physical reattachment process as part of a local thermodynamic equilibrium description of the plasma flow. The fluid and electromagnetic equations describing the plasma flow are solved in a fully-coupled approach by a variational multi-scale finite element method, which implicitly accounts for the multi-scale nature of the flow. The effectiveness of our modelling approach is demonstrated by simulations of a commercial plasma spraying torch operating with Ar-He under different operating conditions. The model is able to match the experimentally measured peak frequencies of the voltage signal, arc lengths and anode spot sizes, but produces voltage drops exceeding those measured. This finding, added to the apparent lack of a well-defined cold boundary layer all around the arc, points towards the importance of non-equilibrium effects inside the torch, especially in the anode attachment region.

  12. A Course on Plasma Processing in Integrated Circuit Fabrication.

    Science.gov (United States)

    Sawin, Herbert H.; Reif, Rafael

    1983-01-01

    Describes a course, taught jointly by electrical/chemical engineering departments at the Massachusetts Institute of Technology, designed to teach the fundamental science of plasma processing as well as to give an overview of the present state of industrial processes. Provides rationale for course development, texts used, class composition, and…

  13. Plasma process for development of a bulk heterojunction optoelectronic device: A highly sensitive UV detector

    Science.gov (United States)

    Sharma, Shyamalima; Pal, Arup R.; Chutia, Joyanti; Bailung, Heremba; Sarma, Neelotpal S.; Dass, Narendra N.; Patil, Dinkar

    2012-08-01

    Deposition of composite thin film of polyaniline/TiO2 (PAni/TiO2) has been carried out by a combined process of magnetron sputtering and plasma polymerization at a pressure of 5 × 10-2 Torr using titanium as a target material for sputtering, aniline as monomer, oxygen as reactive gas and argon as carrier gas/ion source for sputtering. The deposition has been achieved using direct current (dc) discharge power of 35 W for sputtering and radio frequency (rf) power of 8-12 W at substrate bias values in the ranges of -80 to -100 V for polymerization. The composition of the film has been studied using infrared spectroscopy, Raman spectroscopy as well as X-ray photoelectron spectroscopy. The morphology of the film has been characterized with the help of a transmission electron microscopy and atomic force microscopy. The ultraviolet (UV) photo-stability of the composite film has been studied by exposing the film deposited on silicon substrate for different reaction times up to 1 h under UV radiation at wave length range of 280-400 nm with an intensity of 0.4 mW/cm2. An organic/inorganic nanocomposite film based photovoltaic device has been developed. The device has an aluminum/composite/indium tin oxide sandwiched structure that shows strong photoresponse in ultraviolet region and hence the device has potential for application as an UV detector.

  14. Atomic and molecular processes in JT-60U divertor plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Takenaga, H.; Shimizu, K.; Itami, K. [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment] [and others

    1997-01-01

    Atomic and molecular data are indispensable for the understanding of the divertor characteristics, because behavior of particles in the divertor plasma is closely related to the atomic and molecular processes. In the divertor configuration, heat and particles escaping from the main plasma flow onto the divertor plate along the magnetic field lines. In the divertor region, helium ash must be effectively exhausted, and radiation must be enhanced for the reduction of the heat load onto the divertor plate. In order to exhaust helium ash effectively, the difference between behavior of neutral hydrogen (including deuterium and tritium) and helium in the divertor plasma should be understood. Radiation from the divertor plasma generally caused by the impurities which produced by the erosion of the divertor plate and/or injected by gas-puffing. Therefore, it is important to understand impurity behavior in the divertor plasma. The ions hitting the divertor plate recycle through the processes of neutralization, reflection, absorption and desorption at the divertor plates and molecular dissociation, charge-exchange reaction and ionization in the divertor plasma. Behavior of hydrogen, helium and impurities in the divertor plasmas can not be understood without the atomic and molecular data. In this report, recent results of the divertor study related to the atomic and molecular processes in JT-60U were summarized. Behavior of neural deuterium and helium was discussed in section 2. In section 3, the comparisons between the modelling of the carbon impurity transport and the measurements of C II and C IV were discussed. In section 4, characteristics of the radiative divertor using Ne puffing were reported. The new diagnostic method for the electron density and temperature in the divertor plasmas using the intensity ratios of He I lines was described in section 5. (author)

  15. Tailoring the surface properties of polypropylene films through cold atmospheric pressure plasma (CAPP) assisted polymerization and immobilization of biomolecules for enhancement of anti-coagulation activity

    Science.gov (United States)

    Navaneetha Pandiyaraj, K.; Ram Kumar, M. C.; Arun Kumar, A.; Padmanabhan, P. V. A.; Deshmukh, R. R.; Bah, M.; Ismat Shah, S.; Su, Pi-Guey; Halleluyah, M.; Halim, A. S.

    2016-05-01

    Enhancement of anti-thrombogenic properties of polypropylene (PP) to avert the adsorption of plasma proteins (fibrinogen and albumin), adhesion and activation of the platelets are very important for vast biomedical applications. The cold atmospheric pressure plasma (CAPP) assisted polymerization has potential to create the specific functional groups such as Osbnd Cdbnd O, Cdbnd O, Csbnd N and Ssbnd S. on the surface of polymeric films using selective precursor in vapour phase to enhance anti-thrombogenic properties. Such functionalized polymeric surfaces would be suitable for various biomedical applications especially to improve the blood compatibility. The eventual aspiration of the present investigation is to develop the biofunctional coating onto the surface of PP films using acrylic acid (AAc) and polyethylene glycol (PEG) as a precursor in a vapour phase by incorporating specific functional groups for immobilization of biomolecules such as heparin (HEP), chitosan (CHI) and insulin (INS) on the surface of plasma modified PP films. The surface properties such as hydrophilicity, chemical composition, surface topography of the surface modified PP films were analyzed by contact angle (CA), Fourier transform infrared spectroscopy (FTIR), X-ray photo electron spectroscopy (XPS) and atomic force microscopy (AFM). Furthermore the anti-thrombogenic properties of the surface modified PP films were studied by in vitro tests which include platelet adhesion and protein adsorption analysis. It was found that the anti-thrombogenic properties of the PP films are effectively controlled by the CAPP grafting of AAc and PEG followed by immobilization of biomolecules of heparin, chitosan and insulin. The grafting and immobilization was confirmed by FTIR and XPS through the recognition of specific functional groups such as COOH, Csbnd O, Ssbnd S and Csbnd N. on the surface of PP film. Furthermore, the surface morphology and hydrophilic nature of the PP films also tailored

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

    Science.gov (United States)

    Ellinas, K; Tserepi, A; Gogolides, E

    2011-04-05

    Ordered, hierarchical (triple-scale), superhydrophobic, oleophobic, superoleophobic, and amphiphilic surfaces on poly(methyl methacrylate) PMMA polymer substrates are fabricated using polystyrene (PS) microparticle colloidal lithography, followed by oxygen plasma etching-nanotexturing (for amphiphilic surfaces) and optional subsequent fluorocarbon plasma deposition (for amphiphobic surfaces). The PS colloidal microparticles were assembled by spin-coating. After etching/nanotexturing, the PMMA plates are amphiphilic and exhibit hierarchical (triple-scale) roughness with microscale ordered columns, and dual-scale (hundred nano/ten nano meter) nanoscale texture on the particles (top of the column) and on the etched PMMA surface. The spacing, diameter, height, and reentrant profile of the microcolumns are controlled with the etching process. Following the design requirements for superamphiphobic surfaces, we demonstrate enhancement of both hydrophobicity and oleophobicity as a result of hierarchical (triple-scale) and re-entrant topography. After fluorocarbon film deposition, we demonstrate superhydrophobic surfaces (contact angle for water 168°, compared to 110° for a flat surface), as well as superoleophobic surfaces (153° for diiodomethane, compared to 80° for a flat surface).

  17. Synchronous pulsing plasma utilization in dummy poly gate removal process

    Science.gov (United States)

    Huang, Ruixuan; Meng, Xiao-Ying; Han, Qiu-Hua; Zhang, Hai-Yang

    2015-03-01

    When CMOS technology reaches 28/20nm node and beyond, several new schemes are implemented such as High K metal gate (HKMG) which can enhance the device performance and has better control of device current leakage. Dummy poly gate removal (DPGR) process is introduced for HKMG, and works as a key process to control the work function of metal gate and threshold voltage (Vt) shift. In dry etch technology, conventional continuous wave (CW) plasma process has been widely used, however, it may not be capable for some challenging process in 28nm node and beyond. In DPGR process for HKMG scheme, CW scheme may result in plasma damage of gate oxide/capping layer for its inherent high electron temperature (Te) and ion energy while synchronous pulsing scheme is capable to simultaneously pulse both source and bias power, which could achieve lower Te, independent control of ion and radical flux, well control the loading of polymer deposition on dense/ isolate features. It's the first attempt to utilize synchronous pulsing plasma in DPGR process. Experiment results indicate that synchronous pulsing could provide less silicon recess under thin gate oxide which is induced by the plasma oxidation. Furthermore, the loading of HK capping layer loss between long channel and short channel can be well controlled which plays a key role on transistor performance, such as leakage and threshold voltage shift. Additionally, it has been found that synchronous pulsing could distinctly improve ILD loss when compared with CW, which is helpful to broaden the whole process window.

  18. Improved Bone Formation in Osteoporotic Rabbits with the Bone Morphogenetic Protein-2 (rhBMP-2 Coated Titanium Screws Which Were Coated By Using Plasma Polymerization Technique

    Directory of Open Access Journals (Sweden)

    Salih Gulsen

    2014-06-01

    Full Text Available Delaying of bone fusion in osteoporotic patients underwent spinal stabilization surgery leads to screw loosening, and this causes pseudoarticulation, mobility and fibrosis at vertebral segments. To prevent these complications, the screws coated with recombinant bone morphogenetic protein-2 (rhBMP-2 could be used. To verify this hypothesis, we coated 5 Titanium screws with rhBMP-2 using plasma polymerization method, and also used 10 uncoated screws for making comparison between coated and uncoated screws in different groups. And 15 skeletally mature white New Zealand female rabbits were assigned into three different groups: Group 1(N = 5: No osteoporosis induction and insertion of uncoated Titanium screw into right sacrum of each rabbit in group 1; group 2 (N = 5: Osteoporosis induction and insertion of uncoated Titanium screw into right sacrum of each rabbit in group 2; group 3 (N = 5 rhBMP-2 coated Titanium screw inserted into right sacrum of each rabbit in group 3. In summary, using of these coated screws provides new bone formation, but causes less fibrosis and less inflammation than uncoated screws at the interface between the coated screw and bone. Then the plasma polymerization technique provides controlled releasing of rhBMP-2 from the screw to the bone tissue in osteoporotic rabbits.

  19. Gallic acid tailoring surface functionalities of plasma-polymerized allylamine-coated 316L SS to selectively direct vascular endothelial and smooth muscle cell fate for enhanced endothelialization.

    Science.gov (United States)

    Yang, Zhilu; Xiong, Kaiqin; Qi, Pengkai; Yang, Ying; Tu, Qiufen; Wang, Jin; Huang, Nan

    2014-02-26

    The creation of a platform for enhanced vascular endothelia cell (VEC) growth while suppressing vascular smooth muscle cell (VSMC) proliferation offers possibility for advanced coatings of vascular stents. Gallic acid (GA), a chemically unique phenolic acid with important biological functions, presents benefits to the cardiovascular disease therapy because of its superior antioxidant effect and a selectivity to support the growth of ECs more than SMCs. In this study, GA was explored to tailor such a multifunctional stent surface combined with plasma polymerization technique. On the basis of the chemical coupling reaction, GA was bound to an amine-group-rich plasma-polymerized allylamine (PPAam) coating. The GA-functionalized PPAam (GA-PPAam) surface created a favorable microenvironment to obtain high ECs and SMCs selectivity. The GA-PPAam coating showed remarkable enhancement in the adhesion, viability, proliferation, migration, and release of nitric oxide (NO) of human umbilical vein endothelial cells (HUVECs). The GA-PPAam coating also resulted in remarkable inhibition effect on human umbilical artery smooth muscle cell (HUASMC) adhesion and proliferation. These striking findings may provide a guide for designing the new generation of multifunctional vascular devices.

  20. Plasma Polymerization of SnOxCy Organic-Like Films and Grafted PNIPAAm Composite Hydrogel with Nanogold Particles for Promotion of Thermal Resistive Properties

    Directory of Open Access Journals (Sweden)

    Chin-Yen Chou

    2016-12-01

    Full Text Available In this study, a new type of temperature sensor device was developed. The circular electrode of the thermally sensitive sensor was modified with tetramethyltin (TMT and O2 plasma to form a thin SnOxCy conductive layer on the electrode surface. The nano-Au particles (AuNPs were subjected to O2 plasma pretreatment to form peroxide groups on the surface. The thermally sensitive sensor made by mixing the treated AuNPs with N-isopropylacrylamide (NIPAAm solution and then applying UV-induced grafting polymerization of the NIPAAm-containing solution onto the electrode substrate. The composite hydrogels on the electrode introduce thermo-sensitive polymeric surface films for temperature sensing. Using the ambient environment resistance test to measure the resistance, the lower critical solution temperature (LCST of AuNPs mixed with NIPAAm hydrogel was found to be 32 °C. In common metallic materials, the resistance increased during environmental temperature enhancement. In this study, at ambient temperatures higher than the LCST, the electrode resistance decreases linearly due to the shrinkage structure with AuNPs contacting the circuit electrode.

  1. Plasma Processes : Sheath and plasma parameters in a magnetized plasma system

    Indian Academy of Sciences (India)

    Bornali Singha; A Sharma; J Chutia

    2000-11-01

    The variation of electron temperature and plasma density in a magnetized 2 plasma is studied experimentally in presence of a grid placed at the middle of the system. Plasma leaks through the negatively biased grid from the source region into the diffused region. It is observed that the electron temperature increases with the magnetic field in the diffused region whereas it decreases in the source region of the system for a constant grid biasing voltage. Also, investigation is done to see the change of electron temperature with grid biasing voltage for a constant magnetic field. This is accompanied by the study of the variation of sheath structure across the grid for different magnetic field and grid biasing voltage as well. It reveals that with increasing magnetic field and negative grid biasing voltage, the sheath thickness expands.

  2. Characterization of Plasma-Polymerized 4-vinyl pyridine on Poly(Ethylene Terephthalate) film for anti-microbial properties

    DEFF Research Database (Denmark)

    Jiang, Juan; Winther-Jensen, Bjørn; Kjær, Erik Michael

    2005-01-01

    a linear relation between the polymerisation time and the thickness of the surface layer. To further strengthen the antibacterial function the poly-4-vinyl-pyridine surface layer can act as the base for including nano particles of silver precipitated from a salt solution due to ultraviolet radiation....... The mechanical strength of the bond between the substrate and the surface layer has been tested by several methods, and the antibacterial effect of the surface layer with and without silver nano particles has been estimated by measuring electrical resistance as a function of time. The bacteria investigated were......As an efficient way to create an anti-bacterial function on polymer surfaces, we have used plasma polymerisation to create a poly-4-vinyl-pyridine coating on the surface of a common polymer, PET, a polymerisation process that we have shown also works well on several other polymers. We have found...

  3. Numerical simulation of chemical processes in atmospheric plasmas

    Institute of Scientific and Technical Information of China (English)

    Ouyang Jian-Ming; Guo Wei; Wang Long; Shao Fu-Qiu

    2004-01-01

    A model is built to study chemical processes in atmospheric plasmas at low altitude (high pressure) and at high altitude (low pressure). The plasma lifetime and the temporal evolution of the main charged species are presented.The electron number density does not strictly obey the exponential damping law in a long period. The heavy charged species are dominant at low altitude in comparison with the light species at high altitude. Some species of small amount in natural air play an important role in the processes.

  4. Effect of leaching residual methyl methacrylate concentrations on in vitro cytotoxicity of heat polymerized denture base acrylic resin processed with different polymerization cycles

    OpenAIRE

    Canan Bural; Esin AktaŞ; Günnur Deniz; Yeşim Ünlüçerçi; Gülsen Bayraktar

    2011-01-01

    OBJECTIVES: Residual methyl methacrylate (MMA) may leach from the acrylic resin denture bases and have adverse effects on the oral mucosa. This in vitro study evaluated and correlated the effect of the leaching residual MMA concentrations ([MMA]r) on in vitro cytotoxicity of L-929 fibroblasts. MATERIAL AND METHODS: A total of 144 heat-polymerized acrylic resin specimens were fabricated using 4 different polymerization cycles: (1) at 74ºC for 9 h, (2) at 74ºC for 9 h and terminal boiling (at 1...

  5. From pulsed power to processing: Plasma initiated chemical process intensification

    NARCIS (Netherlands)

    Heesch, E.J.M. van; Yan, K.; Pemen, A.J.M.; Winands, G.J.J.; Beckers, F.J.C.M.; Hoeben, W.F.L.M.

    2012-01-01

    Smart electric power for process intensification is a challenging research field that integrates power engineering, chemistry and green technology. Pulsed power technology is offering elegant solutions. This work focuses on backgrounds of matching the power source to the process. Important items are

  6. Physical chemistry research for engineering and applied sciences, v.2 polymeric materials and processing

    CERN Document Server

    Pearce, Eli M; Pethrick, Richard A

    2015-01-01

    PrefaceInvestigation on the Influence of a Strong Electric Field on the Electrical, Transport and Diffusion Properties of Carbon Nanostructures; S. A. Sudorgin and N. G. LebedevA Study Thermal Stability of Polyurethane Elastomers; I. A. Novakov, M. A. Vaniev, D. V. Medvedev, N. V. Sidorenko, G. V. Medvedev, and D. O. GusevTrends in Aromatic Polyesters; Z. S. Khasbulatova and G. E. ZaikovMicroheterogeneous Titanium Ziegler-Natta Catalysts: 1,3-Diene Polymerization Under Ultrasound Irradiations; V. P. Zakharov, V. Z. Mingaleev, I. D. Zakirov

  7. Using in-situ polymerization of conductive polymers to enhance the electrical properties of solution-processed carbon nanotube films and fibers.

    Science.gov (United States)

    Allen, Ranulfo; Pan, Lijia; Fuller, Gerald G; Bao, Zhenan

    2014-07-09

    Single-walled carbon nanotubes/polymer composites typically have limited conductivity due to a low concentration of nanotubes and the insulating nature of the polymers used. Here we combined a method to align carbon nanotubes with in-situ polymerization of conductive polymer to form composite films and fibers. Use of the conducting polymer raised the conductivity of the films by 2 orders of magnitude. On the other hand, CNT fiber formation was made possible with in-situ polymerization to provide more mechanical support to the CNTs from the formed conducting polymer. The carbon nanotube/conductive polymer composite films and fibers had conductivities of 3300 and 170 S/cm, respectively. The relatively high conductivities were attributed to the polymerization process, which doped both the SWNTs and the polymer. In-situ polymerization can be a promising solution-processable method to enhance the conductivity of carbon nanotube films and fibers.

  8. 14th High-Tech Plasma Processes Conference (HTPP 14)

    Science.gov (United States)

    2017-04-01

    Preface The High-Tech Plasma Processes Conference (HTPP) is a bi-annual international conference based in Europe with topics encompassing the whole area of plasma processing science. This conference is open to all the international community in the world involved in plasma science and plasma technology. The aim of the conference is to bring different scientific communities together, facilitate the contacts between science, technology and industry and provide a platform for the exploration of both fundamental topics and new applications of plasmas. For this edition of HTPP, as was the case for the last, we have achieved a well balanced participation from the communities of both thermal and non-thermal plasma researchers. 75 people from 17 countries attended the conference with the total number of contributions being 74, consisting of 19 invited talks and 55 poster contributions. As a HTPP tradition a poster competition has been carried out during the conference. The winner of the poster competition was Fabrice Mavier from Université de Limoges, France with his paper “Pulsed arc plasma jet synchronized with drop-on-demand dispenser” All the participants also ejoyed the social program including an “unconventional” tour of the city, the visit to the famous Hofbräuhaus and the dinner at the Blutenburg, a beautiful inner-city castle. We have received papers corresponding to the contributions of HTPP-2014 that have been submitted for publication in this volume of Journal of Physics: Conference Series. Each submitted contribution has been peer reviewed and the Editors are very grateful to the referees for their careful support in improving the original manuscripts. In total, 18 manuscripts have been accepted for publication covering a range of topics of plasma processing science from plasma fundamentals to process applications through to experiments, diagnostics and modelling. We deeply thank the authors for their enthusiastic and high-grade contributions and we

  9. Investigating the Use of Polymeric Binders in Twin Screw Melt Granulation Process for Improving Compactibility of Drugs.

    Science.gov (United States)

    Batra, Amol; Desai, Dipen; Serajuddin, Abu T M

    2017-01-01

    Traditionally, the melt granulation for pharmaceutical products was performed at low temperature (twin screw extruder where the processing temperature could be increased to as high as 180°C and polymers with high Tg could be used as binders. In this study, different polymeric binders were screened for their suitability in improving compactibility of 2 drugs, metformin hydrochloride and acetaminophen, by twin screw melt granulation. Processing temperatures for the 2 drugs were set at 180°C and 130°C, respectively. Screw configuration, screw speed, and feed rate were optimized such that all polymeric binders used produced granules. Several hydroxypropyl cellulose, hydroxypropyl methylcellulose, polyvinylpyrrolidone, and methacrylate-based polymers, including Klucel(®) EXF, Eudragit(®) EPO, and Soluplus(®), demonstrated good tablet tensile strength (>2 MPa) when granules were produced using only 10% wt/wt polymer concentration. Certain polymers provided acceptable compactibility even at 5% wt/wt. Thus, twin screw melt granulation process may be used with different polymers at a wide range of temperature. Due to low excipient concentration, this granulation method is especially suitable for high-dose tablets.

  10. On the iodine doping process of plasma polymerised thiophene layers

    NARCIS (Netherlands)

    Groenewoud, L.M.H.; Engbers, G.H.M.; White, R.; Feijen, Jan

    2002-01-01

    To make a fair comparison of the conductive properties of plasma polymerised thiophene (PPT) layers deposited under different conditions, optimal doping procedures should be applied. The iodine doping process of PPT layers deposited at high (HP) and low (LP) pressure has been studied in detail.

  11. Cold plasma as a nonthermal food processing technology

    Science.gov (United States)

    Contamination of meats, seafood, poultry, eggs, and fresh and fresh-cut fruits and vegetables is an ongoing concern. Although well-established in non-food applications for surface treatment and modification, cold plasma is a relatively new food safety intervention. As a nonthermal food processing te...

  12. Electron beam generated plasmas for the processing of graphene

    Science.gov (United States)

    Walton, S. G.; Hernández, S. C.; Boris, D. R.; Petrova, Tz B.; Petrov, G. M.

    2017-09-01

    The Naval Research Laboratory (NRL) has developed a processing system based on an electron beam-generated plasma and applied it to the processing of graphene. Unlike conventional discharges produced by electric fields (DC, RF, microwave, etc), the plasma is driven by a high-energy (~few keV) electron beam, an approach that simplifies the relative production of species while providing comparatively high ion-to-radical production rates. The resulting plasmas are characterized by high charged particle densities (1010-1011 cm-3) and electron temperatures that are typically about 1.0 eV or lower. Accordingly, the flux to adjacent surfaces is generally dominated by ions with kinetic energies in the range of 1-5 eV, a value at or near the bond strength of most materials. This provides the potential for controllably engineering materials with monolayer precision, an attribute attractive for the processing of atomically thin material systems. This work describes the attributes of electron beam driven plasma processing system and its use in modification of graphene.

  13. On the iodine doping process of plasma polymerised thiophene layers

    NARCIS (Netherlands)

    Groenewoud, L.M.H.; Engbers, G.H.M.; White, R.; Feijen, J.

    2001-01-01

    To make a fair comparison of the conductive properties of plasma polymerised thiophene (PPT) layers deposited under different conditions, optimal doping procedures should be applied. The iodine doping process of PPT layers deposited at high (HP) and low (LP) pressure has been studied in detail. Dopi

  14. Making Polymeric Microspheres

    Science.gov (United States)

    Rhim, Won-Kyu; Hyson, Michael T.; Chung, Sang-Kun; Colvin, Michael S.; Chang, Manchium

    1989-01-01

    Combination of advanced techniques yields uniform particles for biomedical applications. Process combines ink-jet and irradiation/freeze-polymerization techniques to make polymeric microspheres of uniform size in diameters from 100 to 400 micrometer. Microspheres used in chromatography, cell sorting, cell labeling, and manufacture of pharmaceutical materials.

  15. Polymeric microspheres

    Science.gov (United States)

    Walt, David R.; Mandal, Tarun K.; Fleming, Michael S.

    2004-04-13

    The invention features core-shell microsphere compositions, hollow polymeric microspheres, and methods for making the microspheres. The microspheres are characterized as having a polymeric shell with consistent shell thickness.

  16. Plasma Processes and Polymers: 16th International Symposium on Plasma Chemistry Taormina, Italy June 22-27, 2003

    Science.gov (United States)

    D'Agostino, Riccardo; Favia, Pietro; Oehr, Christian; Wertheimer, Michael R.

    2005-04-01

    This volume compiles essential contributions to the most innovative fields of Plasma Processes and Polymers. High-quality contributions cover the fields of plasma deposition, plasma treatment of polymers and other organic compounds, plasma processes under partial vacuum and at atmospheric pressure, biomedical, textile, automotive, and optical applications as well as surface treatment of bulk materials, clusters, particles and powders. This unique collection of refereed papers is based on the best contributions presented at the 16th International Symposium on Plasma Chemistry in Taormina, Italy (ISPC-16, June 2003). A high class reference of relevance to a large audience in plasma community as well as in the area of its industrial applications.

  17. Preparation of Transparent Bulk TiO2/PMMA Hybrids with Improved Refractive Indices via an in Situ Polymerization Process Using TiO2 Nanoparticles Bearing PMMA Chains Grown by Surface-Initiated Atom Transfer Radical Polymerization.

    Science.gov (United States)

    Maeda, Satoshi; Fujita, Masato; Idota, Naokazu; Matsukawa, Kimihiro; Sugahara, Yoshiyuki

    2016-12-21

    Transparent TiO2/PMMA hybrids with a thickness of 5 mm and improved refractive indices were prepared by in situ polymerization of methyl methacrylate (MMA) in the presence of TiO2 nanoparticles bearing poly(methyl methacrylate) (PMMA) chains grown using surface-initiated atom transfer radical polymerization (SI-ATRP), and the effect of the chain length of modified PMMA on the dispersibility of modified TiO2 nanoparticles in the bulk hybrids was investigated. The surfaces of TiO2 nanoparticles were modified with both m-(chloromethyl)phenylmethanoyloxymethylphosphonic acid bearing a terminal ATRP initiator and isodecyl phosphate with a high affinity for common organic solvents, leading to sufficient dispersibility of the surface-modified particles in toluene. Subsequently, SI-ATRP of MMA was achieved from the modified surfaces of the TiO2 nanoparticles without aggregation of the nanoparticles in toluene. The molecular weights of the PMMA chains cleaved from the modified TiO2 nanoparticles increased with increases in the prolonging of the polymerization period, and these exhibited a narrow distribution, indicating chain growth controlled by SI-ATRP. The nanoparticles bearing PMMA chains were well-dispersed in MMA regardless of the polymerization period. Bulk PMMA hybrids containing modified TiO2 nanoparticles with a thickness of 5 mm were prepared by in situ polymerization of the MMA dispersion. The transparency of the hybrids depended significantly on the chain length of the modified PMMA on the nanoparticles, because the modified PMMA of low molecular weight induced aggregation of the TiO2 nanoparticles during the in situ polymerization process. The refractive indices of the bulk hybrids could be controlled by adjusting the TiO2 content and could be increased up to 1.566 for 6.3 vol % TiO2 content (1.492 for pristine PMMA).

  18. Research of Plasma Spraying Process on Aluminum-Magnesium Alloy

    Directory of Open Access Journals (Sweden)

    Patricija Kavaliauskaitė

    2016-04-01

    Full Text Available The article examines plasma sprayed 95Ni-5Al coatings on alu-minum-magnesium (Mg ≈ 2,6‒3,6 % alloy substrate. Alumi-num-magnesium samples prior spraying were prepared with mechanical treatment (blasting with Al2O3. 95Ni-5Al coatings on aluminum-magnesium alloys were sprayed with different parameters of process and coating‘s thickness, porosity, micro-hardness and microstructure were evaluated. Also numerical simulations in electric and magnetic phenomena of plasma spray-ing were carried out.

  19. Optimization of the process of plasma ignition of coal

    Energy Technology Data Exchange (ETDEWEB)

    Peregudov, V.S. [Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2009-04-15

    Results are given of experimental and theoretical investigations of plasma ignition of coal as a result of its thermochemical preparation in application to the processes of firing up a boiler and stabilizing the flame combustion. The experimental test bed with a commercial-scale burner is used for determining the conditions of plasma ignition of low-reactivity high-ash anthracite depending on the concentration of coal in the air mixture and velocity of the latter. The calculations produce an equation (important from the standpoint of practical applications) for determining the energy expenditure for plasma ignition of coal depending on the basic process parameters. The tests reveal the difficulties arising in firing up a boiler with direct delivery of pulverized coal from the mill to furnace. A scheme is suggested, which enables one to reduce the energy expenditure for ignition of coal and improve the reliability of the process of firing up such a boiler. Results are given of calculation of plasma thermochemical preparation of coal under conditions of lower concentration of oxygen in the air mixture.

  20. Prediction of plasma simulation data with the Gaussian process method

    Energy Technology Data Exchange (ETDEWEB)

    Preuss, R.; Toussaint, U. von, E-mail: udo.v.toussaint@ipp.mpg.de [Max-Planck-Institute for Plasma Physics, EURATOM Association, 85748 Garching (Germany)

    2014-12-05

    The simulation of plasma-wall interactions of fusion plasmas is extremely costly in computer power and time - the running time for a single parameter setting is easily in the order of weeks or months. We propose to exploit the already gathered results in order to predict the outcome for parametric studies within the high dimensional parameter space. For this we utilize Gaussian processes within the Bayesian framework and perform validation with one and two dimensional test cases from which we learn how to assess the outcome. Finally, the newly implemented method is applied to simulated data from the scrape-off layer of a fusion plasma. Uncertainties of the predictions are provided which point the way to parameter settings of further (expensive) simulations.

  1. Generation of low-temperature air plasma for food processing

    Science.gov (United States)

    Stepanova, Olga; Demidova, Maria; Astafiev, Alexander; Pinchuk, Mikhail; Balkir, Pinar; Turantas, Fulya

    2015-11-01

    The project is aimed at developing a physical and technical foundation of generating plasma with low gas temperature at atmospheric pressure for food industry needs. As known, plasma has an antimicrobial effect on the numerous types of microorganisms, including those that cause food spoilage. In this work an original experimental setup has been developed for the treatment of different foods. It is based on initiating corona or dielectric-barrier discharge in a chamber filled with ambient air in combination with a certain helium admixture. The experimental setup provides various conditions of discharge generation (including discharge gap geometry, supply voltage, velocity of gas flow, content of helium admixture in air and working pressure) and allows for the measurement of the electrical discharge parameters. Some recommendations on choosing optimal conditions of discharge generation for experiments on plasma food processing are developed.

  2. Influence of polymerization method, curing process, and length of time of storage in water on the residual methyl methacrylate content in dental acrylic resins.

    Science.gov (United States)

    Bayraktar, Gulsen; Guvener, Bora; Bural, Canan; Uresin, Yagiz

    2006-02-01

    This study compared the influence of different polymerization methods (heat, auto-, and microwave energy), different curing processes (in the case of heat- and autopolymerized specimens), and length of storage of the polymerized specimens in distilled water at 37 degrees C on the residual methyl methacrylate (MMA) content in dental acrylic resin specimens. Residual MMA of 120 resin specimens were measured using high-performance liquid chromatography. For the heat-polymerized resins, the lowest residual MMA content was obtained when they were given a long-term terminal boil and then stored in the distilled water for at least 1 day. For the autopolymerized resins, the lowest residual MMA content was obtained when they were additionally cured in water at 60 degrees C and then stored in the distilled water at least 1 day. For the microwave-polymerized resins, the lowest residual MMA content was obtained when they were stored in the distilled water at least 1 month. The lowest overall residual MMA content was obtained from heat-polymerized specimens that were given a long-term terminal boil cure and then stored in the distilled water at least 1 day. Different polymerization methods and curing processes have different effects on residual MMA content. It is thus shown that storing a dental acrylic resin specimen in distilled water at 37 degrees C is a simple but effective method of reducing its residual MMA content.

  3. Nonlinear processes in the strong wave-plasma interaction

    Science.gov (United States)

    Pegoraro, Francesco; Califano, Francesco; Attico, Nicola; Bulanov, Sergei

    2000-10-01

    Nonlinear interactions in hot laboratory and/or astrophysical plasmas are a very efficient mechanism able to transfer the energy from the large to the small spatial scales of the system. As a result, kinetic processes are excited and play a key role in the plasma dynamics since the typical fluid dissipative length scales (where the nonlinear cascade is stopped) are (much) smaller then the kinetic length scales. Then, the key point is the role of the kinetic effects in the global plasma dynamics, i.e. whether the kinetic effects remains confined to the small scales of the system or whether there is a significant feedback on the large scales. Here we will address this problem by discussing the nonlinear kinetic evolution of the electromagnetic beam plasma instability where phase space vortices, as well as large scale vortex like magnetic structures in the physical space, are generated by wave - particle interactions. The role and influence of kinetic effects on the large scale plasma dynamics will be also discussed by addressing the problem of collisionless magnetic reconection.

  4. Process characteristics of fibre-laser-assisted plasma arc welding

    Energy Technology Data Exchange (ETDEWEB)

    Mahrle, A; Schnick, M; Rose, S; Demuth, C; Beyer, E; Fuessel, U, E-mail: achim.mahrle@iws.fraunhofer.de [Dresden University of Technology, Institute of Surface and Manufacturing Technology, PO Box, D-01062 Dresden (Germany)

    2011-08-31

    Experimental and theoretical investigations on fibre-laser-assisted plasma arc welding (LAPW) were performed. Welding experiments were carried out on aluminium and steel sheets. In the case of a highly focused laser beam and a separate arrangement of plasma torch and laser beam, high-speed video recordings of the plasma arc and corresponding measurements of the time-dependent arc voltage revealed differences in the process behaviour for both materials. In the case of aluminium welding, a sharp decline in arc voltage and stabilization and guiding of the anodic arc root was observed whereas in steel welding the arc voltage was slightly increased after the laser beam was switched on. However, significant improvement of the melting efficiency with the combined action of plasma arc and laser beam was achieved for both types of material. Theoretical results of additional numerical simulations of the arc behaviour suggest that the properties of the arc plasma are mainly influenced not by a direct interaction with the laser radiation but by the laser-induced evaporation of metal. Arc stabilization with increased current densities is predicted for moderate rates of evaporated metal only whereas metal vapour rates above a certain threshold causes a destabilization of the arc and reduced current densities along the arc axis.

  5. Plasma process optimization for N-type doping applications

    Energy Technology Data Exchange (ETDEWEB)

    Raj, Deven; Persing, Harold; Salimian, Siamak; Lacey, Kerry; Qin Shu; Hu, Jeff Y.; McTeer, Allen [Applied Materials, Inc., Varian Semiconductor Business Unit, 35 Dory Road, Gloucester, MA 01930 (United States); Micron Technology, Inc., 8000 S. Federal Way, Boise, ID 83707 (United States)

    2012-11-06

    Plasma doping (PLAD) has been adopted across the implant technology space and into high volume production for both conventional DRAM and NAND doping applications. PLAD has established itself as an alternative to traditional ion implantation by beamline implantation. The push for high doping concentration, shallow doping depth, and conformal doping capability expand the need for a PLAD solution to meet such requirements. The unique doping profile and doping characteristics at high dose rates allow for PLAD to deliver a high throughput, differentiated solution to meet the demand of evolving transistor technology. In the PLAD process, ions are accelerated to the wafer as with a negative wafer bias applied to the wafer. Competing mechanisms, such as deposition, sputtering, and etching inherent in plasma doping require unique control and process optimization. In this work, we look at the distinctive process tool control and characterization features which enable an optimized doping process using n-type (PH{sub 3} or AsH{sub 3}) chemistries. The data in this paper will draw the relationship between process optimization through plasma chemistry study to the wafer level result.

  6. Synthesis, recognition and evaluation of molecularly imprinted polymer nanoparticle using miniemulsion polymerization for controlled release and analysis of risperidone in human plasma samples

    Energy Technology Data Exchange (ETDEWEB)

    Asadi, Ebadullah; Azodi-Deilami, Saman; Abdouss, Majid [Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Kordestani, Davood [Razi University, Kermanshah (Iran, Islamic Republic of); Rahimi, Alireza [Research Institute of Petroleum Industry (RIPI), Tehran (Iran, Islamic Republic of); Asadi, Somayeh [Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of)

    2014-06-15

    We prepared high selective imprinted nanoparticle polymers by a miniemulsion polymerization technique, using risperidone as the template, MAA as the functional monomers, and TRIM as the cross-linker in acetonitrile as solvent. The morphology of the nanoparticles determined by scanning electron microscopy (SEM) images and drug release, binding properties and dynamic light scattering (DLS) of molecularly imprinted polymers (MIPs) were studied. Controlled release of risperidone from nanoparticles was investigated through in 1% wt sodium dodecyl sulfate aqueous solution and by measuring the absorbance by HPLC-UV. The results showed that the imprinted nanoparticles exhibited a higher binding level and slower release rate than non-imprinted nanoparticles, which contributed to interaction of risperidone with imprinted cavities within nanoparticles. Furthermore, the results from HPLC showed good precision (5% for 50.0 µg L{sup -1}) and recoveries (between 86-91) using MIP from human plasma samples.

  7. Frequency dependent plasma characteristics in a capacitively coupled 300 mm wafer plasma processing chamber

    Energy Technology Data Exchange (ETDEWEB)

    Hebner, Gregory A [Sandia National Laboratories, Albuquerque NM 87185-1423 (United States); Barnat, Edward V [Sandia National Laboratories, Albuquerque NM 87185-1423 (United States); Miller, Paul A [Sandia National Laboratories, Albuquerque NM 87185-1423 (United States); Paterson, Alex M [Applied Materials, 974 Arques Avenue, Sunnyvale CA, 94086 (United States); Holland, John P [Applied Materials, 974 Arques Avenue, Sunnyvale CA, 94086 (United States)

    2006-11-01

    Argon plasma characteristics in a dual-frequency, capacitively coupled, 300 mm-wafer plasma processing system were investigated for rf drive frequencies between 10 and 190 MHz. We report spatial and frequency dependent changes in plasma parameters such as line-integrated electron density, ion saturation current, optical emission and argon metastable density. For the conditions investigated, the line-integrated electron density was a nonlinear function of drive frequency at constant rf power. In addition, the spatial distribution of the positive ions changed from uniform to peaked in the centre as the frequency was increased. Spatially resolved optical emission increased with frequency and the relative optical emission at several spectral lines depended on frequency. Argon metastable density and spatial distribution were not a strong function of drive frequency. Metastable temperature was approximately 400 K.

  8. Plasma-induced polymerization as a tool for surface functionalization of polymer scaffolds for bone tissue engineering: an in vitro study.

    Science.gov (United States)

    López-Pérez, Paula M; da Silva, Ricardo M P; Sousa, Rui A; Pashkuleva, Iva; Reis, Rui L

    2010-09-01

    A commonly applied strategy in the field of tissue engineering (TE) is the use of temporary three-dimensional scaffolds for supporting and guiding tissue formation in various in vitro strategies and in vivo regeneration approaches. The interactions of these scaffolds with highly sensitive bioentities such as living cells and tissues primarily occur through the material surface. Hence, surface chemistry and topological features have principal roles in coordinating biological events at the molecular, cellular and tissue levels on timescales ranging from seconds to weeks. However, tailoring the surface properties of scaffolds with a complex shape and architecture remains a challenge in materials science. Commonly applied wet chemical treatments often involve the use of toxic solvents whose oddments in the construct could be fatal in the subsequent application. Aiming to shorten the culture time in vitro (i.e. prior the implantation of the construct), in this work we propose a modification of previously described bone TE scaffolds made from a blend of starch with polycaprolactone (SPCL). The modification method involves surface grafting of sulfonic or phosphonic groups via plasma-induced polymerization of vinyl sulfonic and vinyl phosphonic acid, respectively. We demonstrate herein that the presence of these anionic functional groups can modulate cell adhesion mediated through the adsorbed proteins (from the culture medium). Under the conditions studied, both vitronectin adsorption and osteoblast proliferation and viability increased in the order SPCL plasma-induced polymerization is an excellent alternative route, when compared to the commonly used wet chemical treatments, for the surface functionalization of biodevices with complex shape and porosity.

  9. Plasma process control for improved PEO coatings on magnesium alloys

    Science.gov (United States)

    Hussein, Riyad Omran

    Plasma Electrolytic Oxidation (PEO) is a high voltage plasma-assisted oxidation process uses an environmentally-friendly aqueous electrolyte to oxidize the metal surfaces to form ceramic oxide coatings which impart a high corrosion and wear resistance. One of the main advantages of PEO process is that it can be applied to treat samples with complex shapes, and surfaces with different composition and microstructure. The PEO process of Mg alloys is strongly influenced by such parameters as electrolyte composition and concentration, current or voltage applied and substrate alloy. Generally, these parameters have a direct influence on the discharging behavior. The discharges play an essential role in the formation and resulting composition of the 3-layer oxide structure. A detailed knowledge of the coating mechanisms is extremely important in order to produce a desired coating quality to reach the best performance of the PEO coatings in terms of corrosion resistance and tribological properties (wear rate, COF). During PEO processing of magnesium, some of the metal cations are transferred outwards from the substrate and react with anions to form ceramic coatings. Also, due to the high electric field in the discharge channels, oxygen anions transfer towards the magnesium substrate and react with Mg2+ cations to form a ceramic coating. Although, in general, PEO coating of Mg alloys produces the three-layered structure, the relative proportions of the three-layers are strongly influenced by the PEO processing parameters. In PEO process, the ceramic coating grows inwards to the alloy substrate and outwards to the coating surface simultaneously. For the coating growth, there are three simultaneous processes taking place, namely the electrochemical, the plasma chemical reactions and thermal diffusion. Optical emission spectroscopy (OES) was employed for the discharge characterization by following the substrate and electrolyte element present in the plasma discharge during the

  10. Plasma nitriding monitoring reactor: A model reactor for studying plasma nitriding processes using an active screen

    Energy Technology Data Exchange (ETDEWEB)

    Hamann, S., E-mail: hamann@inp-greifswald.de; Röpcke, J. [INP-Greifswald, Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Börner, K.; Burlacov, I.; Spies, H.-J. [TU Bergakademie Freiberg, Institute of Materials Engineering, Gustav-Zeuner-Str. 5, 09599 Freiberg (Germany); Strämke, M.; Strämke, S. [ELTRO GmbH, Arnold-Sommerfeld-Ring 3, 52499 Baesweiler (Germany)

    2015-12-15

    A laboratory scale plasma nitriding monitoring reactor (PLANIMOR) has been designed to study the basics of active screen plasma nitriding (ASPN) processes. PLANIMOR consists of a tube reactor vessel, made of borosilicate glass, enabling optical emission spectroscopy (OES) and infrared absorption spectroscopy. The linear setup of the electrode system of the reactor has the advantages to apply the diagnostic approaches on each part of the plasma process, separately. Furthermore, possible changes of the electrical field and of the heat generation, as they could appear in down-scaled cylindrical ASPN reactors, are avoided. PLANIMOR has been used for the nitriding of steel samples, achieving similar results as in an industrial scale ASPN reactor. A compact spectrometer using an external cavity quantum cascade laser combined with an optical multi-pass cell has been applied for the detection of molecular reaction products. This allowed the determination of the concentrations of four stable molecular species (CH{sub 4}, C{sub 2}H{sub 2}, HCN, and NH{sub 3}). With the help of OES, the rotational temperature of the screen plasma could be determined.

  11. Plasma nitriding monitoring reactor: A model reactor for studying plasma nitriding processes using an active screen

    Science.gov (United States)

    Hamann, S.; Börner, K.; Burlacov, I.; Spies, H.-J.; Strämke, M.; Strämke, S.; Röpcke, J.

    2015-12-01

    A laboratory scale plasma nitriding monitoring reactor (PLANIMOR) has been designed to study the basics of active screen plasma nitriding (ASPN) processes. PLANIMOR consists of a tube reactor vessel, made of borosilicate glass, enabling optical emission spectroscopy (OES) and infrared absorption spectroscopy. The linear setup of the electrode system of the reactor has the advantages to apply the diagnostic approaches on each part of the plasma process, separately. Furthermore, possible changes of the electrical field and of the heat generation, as they could appear in down-scaled cylindrical ASPN reactors, are avoided. PLANIMOR has been used for the nitriding of steel samples, achieving similar results as in an industrial scale ASPN reactor. A compact spectrometer using an external cavity quantum cascade laser combined with an optical multi-pass cell has been applied for the detection of molecular reaction products. This allowed the determination of the concentrations of four stable molecular species (CH4, C2H2, HCN, and NH3). With the help of OES, the rotational temperature of the screen plasma could be determined.

  12. Plasma nitriding monitoring reactor: A model reactor for studying plasma nitriding processes using an active screen.

    Science.gov (United States)

    Hamann, S; Börner, K; Burlacov, I; Spies, H-J; Strämke, M; Strämke, S; Röpcke, J

    2015-12-01

    A laboratory scale plasma nitriding monitoring reactor (PLANIMOR) has been designed to study the basics of active screen plasma nitriding (ASPN) processes. PLANIMOR consists of a tube reactor vessel, made of borosilicate glass, enabling optical emission spectroscopy (OES) and infrared absorption spectroscopy. The linear setup of the electrode system of the reactor has the advantages to apply the diagnostic approaches on each part of the plasma process, separately. Furthermore, possible changes of the electrical field and of the heat generation, as they could appear in down-scaled cylindrical ASPN reactors, are avoided. PLANIMOR has been used for the nitriding of steel samples, achieving similar results as in an industrial scale ASPN reactor. A compact spectrometer using an external cavity quantum cascade laser combined with an optical multi-pass cell has been applied for the detection of molecular reaction products. This allowed the determination of the concentrations of four stable molecular species (CH4, C2H2, HCN, and NH3). With the help of OES, the rotational temperature of the screen plasma could be determined.

  13. The variable polarity plasma arc welding process: Characteristics and performance

    Science.gov (United States)

    Hung, R. J.; Zhu, G. J.

    1991-01-01

    Significant advantages of the Variable Polarity Plasma Arc (VPPA) Welding Process include faster welding, fewer repairs, less joint preparation, reduced weldment distortion, and absence of porosity. The power distribution was analyzed for an argon plasma gas flow constituting the fluid in the VPPA Welding Process. The major heat loss at the torch nozzle is convective heat transfer; in the space between the outlet of the nozzle and the workpiece; radiative heat transfer; and in the keyhole in the workpiece, convective heat transfer. The power absorbed at the workpiece produces the molten puddle that solidifies into the weld bead. Crown and root widths, and crown and root heights of the weld bead are predicted. The basis is provided for an algorithm for automatic control of VPPA welding machine parameters to obtain desired weld bead dimensions.

  14. EXAFS investigation of nanoparticles produced in a thermal plasma process

    Energy Technology Data Exchange (ETDEWEB)

    Luetzenkirchen-Hecht, D.; Frahm, R. [Heinrich-Heine-Univ. Duesseldorf, Inst. fuer Angewandte Physik (Germany); Buchner, P. [Heinrich-Heine-Univ. Duesseldorf, Inst. fuer Laser- und Plasmaphysik (Germany); Strehblow, H.H. [Heinrich-Heine-Univ., Inst. fuer Physikalische Chemie (Germany)

    1999-11-01

    Nanosized ceramic powders (Cu/SiC, Y{sub 2}O{sub 3}-stabilized cubic ZrO{sub 2}) were produced by evaporation of coarsely grained powders of the respective materials in an inductively coupled thermal plasma process and rapid quenching of the vapor. The atomic short range order of these nanoparticles with an average diameter of about 10 nm was investigated ex situ with EXAFS. The results are compared to crystalline reference materials. (au) 10 refs.

  15. Solubility of drugs in aqueous polymeric solution: effect of ovalbumin on microencapsulation process.

    Science.gov (United States)

    Aziz, Hesham Abdul; Tan, Yvonne Tze Fung; Peh, Kok Khiang

    2012-03-01

    Microencapsulation of water-soluble drugs using coacervation-phase separation method is very challenging, as these drugs partitioned into the aqueous polymeric solution, resulting in poor drug entrapment. For evaluating the effect of ovalbumin on the microencapsulation of drugs with different solubility, pseudoephedrine HCl, verapamil HCl, propranolol HCl, paracetamol, and curcuminoid were used. In addition, drug mixtures comprising of paracetamol and pseudoephedrine HCl were also studied. The morphology, encapsulation efficiency, particle size, and in vitro release profile were investigated. The results showed that the solubility of the drug determined the ratio of ovalbumin to be used for successful microencapsulation. The optimum ratios of drug, ovalbumin, and gelatin for water-soluble (pseudoephedrine HCl, verapamil HCl, and propranolol HCl), sparingly water-soluble (paracetamol), and water-insoluble (curcuminoid) drugs were found to be 1:1:2, 2:3:5, and 1:3:4. As for the drug mixture, the optimum ratio of drug, ovalbumin, and gelatin was 2:3:5. Encapsulated particles prepared at the optimum ratios showed high yield, drug loading, entrapment efficiency, and sustained release profiles. The solubility of drug affected the particle size of the encapsulated particle. Highly soluble drugs resulted in smaller particle size. In conclusion, addition of ovalbumin circumvented the partitioning effect, leading to the successful microencapsulation of water-soluble drugs.

  16. Deposição por plasma com arco transferido Hardfacing by plasma transfer arc process

    Directory of Open Access Journals (Sweden)

    Víctor Vergara Díaz

    2010-03-01

    Full Text Available Em virtude do Processo de Soldagem Plasma com Alimentação de Pó ter similaridades com o Processo de Soldagem Plasma com Alimentação de Arame, foi realizado um estudo comparativo entre ambos os processos utilizando-se a liga a base de cobalto comercialmente conhecida como Stellite 6, como material de adição na forma de pó e arame. A pesquisa foi realizada com a expectativa de ser aplicada nas operações de revestimentos de superfícies, em especial em pás de turbinas hidráulicas desgastadas por cavitação. A seleção do material de adição a ser empregado depende da natureza do mecanismo de desgaste encontrado. No Labsolda, a liga Stellite 6 vem sendo uma das mais utilizadas, por apresentar uma excelente resistência ao desgaste erosivo por cavitação. Foi avaliada a influência da vazão de gás de plasma a partir dos valores de diluição, dimensões do cordão, dureza e microestrutura. O Processo de Soldagem Plasma com Alimentação de Pó foi o que produziu o melhor acabamento superficial, menor diluição, melhor molhamento e maior largura. Com isto abre-se uma nova perspectiva para revestimentos metálicos e neste contexto se insere a recuperação por soldagem de partes erodidas de turbinas hidráulicas.The Plasma powder transferred arc welding process, which uses feed stock in the powder form, has similarities with Plasma wire transferred arc welding. This work describes a comparative study of the two processes using a Cobalt-based alloy commercially known as Stellite 6. This Co-based alloy is recognized for its superior cavitation erosion resistance. The aim of this work is to investigate the potential of PTA coatings for the protection and refurbishiment hydraulic turbine blades. Coatings were evaluated for the influence of Plasma gas flow rate on coating dilution, geometry, hardness and microstructure. Coatings processed with the atomized Stellite 6 powder feestock showed a superior surface quality, lower dilution

  17. The expansion of a plasma into a vacuum - Basic phenomena and processes and applications to space plasma physics

    Science.gov (United States)

    Wright, K. H., Jr.; Stone, N. H.; Samir, U.

    1983-01-01

    In this review attention is called to basic phenomena and physical processes involved in the expansion of a plasma into a vacuum, or the expansion of a plasma into a more tenuous plasma, in particular the fact that upon the expansion, ions are accelerated and reach energies well above their thermal energy. Also, in the process of the expansion a rarefaction wave propagates into the ambient plasma, an ion front moves into the expansion volume, and discontinuities in plasma parameters occur. The physical processes which cause the above phenomena are discussed, and their possible application is suggested for the case of the distribution of ions and electrons (hence plasma potential and electric fields) in the wake region behind artificial and natural obstacles moving supersonically in a rarefied space plasma. To illustrate this, some in situ results are reexamined. Directions for future work in this area via the utilization of the Space Shuttle and laboratory work are also mentioned.

  18. Advanced plasma etching processes for dielectric materials in VLSI technology

    Science.gov (United States)

    Wang, Juan Juan

    Manufacturable plasma etching processes for dielectric materials have played an important role in the Integrated Circuits (IC) industry in recent decades. Dielectric materials such as SiO2 and SiN are widely used to electrically isolate the active device regions (like the gate, source and drain from the first level of metallic interconnects) and to isolate different metallic interconnect levels from each other. However, development of new state-of-the-art etching processes is urgently needed for higher aspect ratio (oxide depth/hole diameter---6:1) in Very Large Scale Integrated (VLSI) circuits technology. The smaller features can provide greater packing density of devices on a single chip and greater number of chips on a single wafer. This dissertation focuses on understanding and optimizing of several key aspects of etching processes for dielectric materials. The challenges are how to get higher selectivity of oxide/Si for contact and oxide/TiN for vias; tight Critical Dimension (CD) control; wide process margin (enough over-etch); uniformity and repeatability. By exploring all of the parameters for the plasma etch process, the key variables are found and studied extensively. The parameters investigated here are Power, Pressure, Gas ratio, and Temperature. In particular, the novel gases such as C4F8, C5F8, and C4F6 were studied in order to meet the requirements of the design rules. We also studied CF4 that is used frequently for dielectric material etching in the industry. Advanced etch equipment was used for the above applications: the medium-density plasma tools (like Magnet-Enhanced Reactive Ion Etching (MERIE) tool) and the high-density plasma tools. By applying the Design of Experiments (DOE) method, we found the key factors needed to predict the trend of the etch process (such as how to increase the etch rates, selectivity, etc.; and how to control the stability of the etch process). We used JMP software to analyze the DOE data. The characterization of the

  19. Detecting cells on the surface of a silver electrode quartz crystal microbalance using plasma treatment and graft polymerization.

    Science.gov (United States)

    Chou, Hung-Che; Yan, Tsong-Rong; Chen, Ko-Shao

    2009-10-15

    This paper utilizes a silver electrode quartz crystal microbalance (QCM) mass sensor to detect the physiology of cells. This study also investigates the plasma surface modification of silver electrode QCMs through deposition of hexamethyldisilazane (HMDSZ) films as a protection film. To improve the cell growth, this paper also performs post-treatments by surface-grafting acrylic acid (AAc), acrylamide (AAm), and oxygen plasma treatment onto the QCM electrodes. Experimental results indicate that plasma deposition is a useful technique to protect the surface of silver electrodes. This technique extends the unpeeling time of silver electrodes from 1 to 7 days. The hydrophilic silver electrode QCM surface modified by AAm exhibited a better storage time effect than other post-treatments.

  20. Spatiotemporal characterization of hydration process of asymmetric polymeric wound dressings for decubitus ulcers.

    Science.gov (United States)

    Górska, Anna; Dorożyński, Przemyslaw; Węglarz, Władysław P; Jasiński, Krzysztof; Kurek, Mateusz; Jachowicz, Renata; Klaja, Jolanta; Kulinowski, Piotr

    2017-04-13

    Pressure ulcers belong to the most chalenging clinical problems. As hydration level of such wounds is important for optimal healing, preparation of new wound dressing (WD) materials for pressure ulcers requires thorough in vitro evaluation as prerequisite to final in vivo testing. The aims of the study were to: (a) develop a simple method of preparation of asymmetric polymeric membrane, (b) to propose a set of in vitro methods for membrane characterization during hydration. A polyvinyl alcohol asymmetric membrane with homogeneous skin layer and porous spongy layer was developed with nonadhesive properties and ability to absorb and retain the water. Complementary methods, including magnetic resonance imaging, allowed quantitative assessment of spatiotemporal aspects of membrane hydration, that is, global water uptake; swelling; local hydration in terms of proton density mapping; spatial distribution of T2 relaxation time; Young's modulus; piercing resistance. The proposed method of initial wound dressing evaluation seems to be promising to compare various WD formulations, to assess the time required to prepare WD membrane to be applied to the wound and to assess how long WD retains desired working properties. The developed asymmetric membrane seems to be a good candidate for further evaluation. It was found that: Young's modulus of hydrated membrane was comparable to those of human skin; asymmetrical structure was retained during the entire hydration period; each layer had its own distinct, hydration related, properties and their spatiotemporal evolution; relatively slow changes of membrane properties during the potential WD application time-span of several hours was observed. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2017. © 2017 Wiley Periodicals, Inc.

  1. DBD atmospheric plasma-modified, electrospun, layer-by-layer polymeric scaffolds for L929 fibroblast cell cultivation.

    Science.gov (United States)

    Surucu, Seda; Turkoglu Sasmazel, Hilal

    2016-01-01

    This paper reported a study related to atmospheric pressure dielectric barrier discharge (DBD) Ar + O2 and Ar + N2 plasma modifications to alter surface properties of 3D PCL/Chitosan/PCL layer-by-layer hybrid scaffolds and to improve mouse fibroblast (L929 ATCC CCL-1) cell attachment, proliferation, and growth. The scaffolds were fabricated using electrospinning technique and each layer was electrospun sequentially on top of the other. The surface modifications were performed with an atmospheric pressure DBD plasma under different gas flow rates (50, 60, 70, 80, 90, and 100 sccm) and for different modification times (0.5-7 min), and then the chemical and topographical characterizations of the modified samples were done by contact angle (CA) measurements, scanning electron microscopy (SEM), atomic force microscopy, and X-ray photoelectron spectroscopy. The samples modified with Ar + O2 plasma for 1 min under 70 cm(3)/min O2 flow rate (71.077° ± 3.578) showed a 18.83% decrease compare to unmodified samples' CA value (84.463° ± 3.864). Comparing with unmodified samples, the average fiber diameter values for plasma-modified samples by Ar + O2 (1 min 70 sccm) and Ar + N2 (40 s 70 sccm) increased 40.756 and 54.295%, respectively. Additionally, the average inter-fiber pore size values exhibited decrease of 37.699 and 48.463% for the same Ar + O2 and Ar + N2 plasma-modified samples, respectively, compare to unmodified samples. Biocompatibility performance was determined with MTT assay, fluorescence, Giemsa, and confocal imaging as well as SEM. The results showed that Ar + O2-based plasma modification increased the hydrophilicity and oxygen functionality of the surface, thus affecting the cell viability and proliferation on/within scaffolds.

  2. Advanced Plasma Pyrolysis Assembly (PPA) Reactor and Process Development

    Science.gov (United States)

    Wheeler, Richard R., Jr.; Hadley, Neal M.; Dahl, Roger W.; Abney, Morgan B.; Greenwood, Zachary; Miller, Lee; Medlen, Amber

    2012-01-01

    Design and development of a second generation Plasma Pyrolysis Assembly (PPA) reactor is currently underway as part of NASA's Atmosphere Revitalization Resource Recovery effort. By recovering up to 75% of the hydrogen currently lost as methane in the Sabatier reactor effluent, the PPA helps to minimize life support resupply costs for extended duration missions. To date, second generation PPA development has demonstrated significant technology advancements over the first generation device by doubling the methane processing rate while, at the same time, more than halving the required power. One development area of particular interest to NASA system engineers is fouling of the PPA reactor with carbonaceous products. As a mitigation plan, NASA MSFC has explored the feasibility of using an oxidative plasma based upon metabolic CO2 to regenerate the reactor window and gas inlet ports. The results and implications of this testing are addressed along with the advanced PPA reactor development.

  3. Magnetic Reconnection: A Fundamental Process in Space Plasmas

    Science.gov (United States)

    Hesse, Michael

    2010-01-01

    For many years, collisionless magnetic reconnect ion has been recognized as a fundamental process, which facilitates plasma transport and energy release in systems ranging from the astrophysical plasmas to magnetospheres and even laboratory plasma. Beginning with work addressing solar dynamics, it has been understood that reconnection is essential to explain solar eruptions, the interaction of the solar wind with the magnetosphere, and the dynamics of the magnetosphere. Accordingly, the process of magnetic reconnection has been and remains a prime target for space-based and laboratory studies, as well as for theoretical research. Much progress has been made throughout the years, beginning with indirect verifications by studies of processes enabled by reconnection, such as Coronal Mass Ejections, Flux Transfer Events, and Plasmoids. Theoretical advances have accompanied these observations, moving knowledge beyond the Sweet-Parker theory to the recognition that other, collisionless, effects are available and likely to support much faster reconnect ion rates. At the present time we are therefore near a break-through in our understanding of how collisionless reconnect ion works. Theory and modeling have advanced to the point that two competing theories are considered leading candidates for explaining the microphysics of this process. Both theories predict very small spatial and temporal scales. which are. to date, inaccessible to space-based or laboratory measurements. The need to understand magnetic reconnect ion has led NASA to begin the implementation of a tailored mission, Magnetospheric MultiScale (MMS), a four spacecraft cluster equipped to resolve all relevant spatial and temporal scales. In this presentation, we present an overview of current knowledge as well as an outlook towards measurements provided by MMS.

  4. Study of the adhesive properties versus stability/aging of hernia repair meshes after deposition of RF activated plasma polymerized acrylic acid coating

    Energy Technology Data Exchange (ETDEWEB)

    Rivolo, Paola [Politecnico di Torino, Department of Applied Science and Technology, C.so Duca degli Abruzzi 24, 10129 Torino (Italy); Nisticò, Roberto, E-mail: roberto.nistico@unito.it [University of Torino, Department of Chemistry and NIS Centre, Via P. Giuria 7, 10125 Torino (Italy); Barone, Fabrizio [University of Torino, Department of Chemistry and NIS Centre, Via P. Giuria 7, 10125 Torino (Italy); Faga, Maria Giulia; Duraccio, Donatella [CNR-IMAMOTER, Strada delle Cacce 73, 10135 Torino (Italy); Martorana, Selanna [Herniamesh S.r.l., Via F.lli Meliga 1/C, 10034 Chivasso (Italy); Ricciardi, Serena [Politecnico di Torino, Department of Applied Science and Technology, C.so Duca degli Abruzzi 24, 10129 Torino (Italy); Magnacca, Giuliana [University of Torino, Department of Chemistry and NIS Centre, Via P. Giuria 7, 10125 Torino (Italy)

    2016-08-01

    In order to confer adhesive properties to commercial polypropylene (PP) meshes, a surface plasma-induced deposition of poly-(acrylic acid) (PPAA) is performed. Once biomaterials were functionalized, different post-deposition treatments (i.e. water washing and/or thermal treatments) were investigated with the aim of monitoring the coating degradation (and therefore the loss of adhesion) after 3 months of aging in both humid/oxidant (air) and inert (nitrogen) atmospheres. A wide physicochemical characterization was carried out in order to evaluate the functionalization effectiveness and the adhesive coating homogeneity by means of static water drop shape analysis and several spectroscopies (namely, FTIR, UV–Visible and X-ray Photoemission Spectroscopy). The modification of the adhesion properties after post-deposition treatments as well as aging under different storage atmospheres were investigated by means of Atomic Force Microscopy (AFM) used in Force/Distance (F/D) mode. This technique confirms itself as a powerful tool for unveiling the surface adhesion capacity as well as the homogeneity of the functional coatings along the fibers. Results obtained evidenced that post-deposition treatments are mandatory in order to remove all oligomers produced during the plasma-treatment, whereas aging tests evidenced that these devices can be simply stored in presence of air for at least three months without a meaningful degradation of the original properties. - Highlights: • Plasma polymerized surface functionalization of hernia-repair meshes was used to confer adhesive properties. • The stability of the adhesive coating was verified under different post-deposition conditions. • The use of AFM in F/D mode was selected to monitor the coating degradation.

  5. Review of relaxation oscillations in plasma processing discharges

    Institute of Scientific and Technical Information of China (English)

    Zhou Zhu-Wen; M.A.Lieberman; Sungjin Kim

    2007-01-01

    Relaxation oscillations due to plasma instabilities at frequencies ranging from a few Hz to tens of kHz have been observed in various types of plasma processing discharges.Relaxation oscillations have been observed in electropositive capacitive discharges between a powered anode and a metallic chamber whose periphery iS grounded through a slot with dielectric spacers.The oscillations of time-varying optical emission from the main discharge chamber show,for example,a high-frequency (~40 kHz) relaxation oscillation at 13.33Pa,with an absorbed power being nearly the peripheral breakdown power,and a low-frequency (~3 Hz) oscillation,with an even higher absorbed power.The high-frequency oscillation is found to ignite plasma in the slot,but usually not in the peripheral chamber.The kilohertz oscillations are modelled using an electromagnetic model of the slot impedance,coupled to a circuit analysis of the system including the matching network.The model results are in general agreement with the experimental observations,and indicate a variety of behaviours dependent on the matching conditions.In low-pressure inductive discharges,oscillations appear in the transition between low-density capacitively driven and high-density inductively driven discharges when attaching gases such as SF6 and Ar/SF6 mixtures are used.Oscillations of charged particles,plasma potential,and light,at frequencies ranging from a few Hz to tens of kHz,are seen for gas pressures between 0.133 Pa and 13.33 Pa and discharge powers in a range of 75-1200 W.The region of instability increases as the plasma becomes more electronegative,and the frequency of plasma oscillation increases as the power,pressure,and gas flow rate increase.A volume-averaged (global) model of the kilohertz instability has been developed;the results obtained from the model agree well with the experimental observations.

  6. Plasma aided coal gasification and the variables in this process

    Energy Technology Data Exchange (ETDEWEB)

    Pang, X.; Lu, Y.; Zhu, S. [Taiyuan University of Technology, Taiyuan (China)

    2005-12-15

    In order to investigate the characters of plasma aided coal gasification in the industry-scale equipment, the tests with changing feeding rate, steam output pressure, feeding gas flux, input power of plasma generator and the additives were carried out with Datong coal. The produced gas components were analyzed by gas chromatography. And the optimal process conditions, such as, the feeding rate of 150 g/min, the feeding gas flow of 18 m{sup 3}/h, the output power of plasma generator of 100 kW, the steam output pressure of 0.3 MPa are obtained. When the contents of CaO and CaCO{sub 3} in the whole feed are 10 and 5% respectively, the experimental data show their catalytic effect is the best. Considering the molar mass of CaO and CaCO{sub 3}, it is concluded that the catalytic effect of CaO is more important than the reduction of CO{sub 2} in the gasification. 12 refs., 2 figs., 3 tabs.

  7. Electron-silane scattering cross section for plasma assisted processes

    Science.gov (United States)

    Verma, Pankaj; Kaur, Jaspreet; Antony, Bobby

    2017-03-01

    Silane is an important molecule with numerous applications to natural and technological plasmas. In such environments, where plasma assisted processes are vital, electron induced reactions play a major role in its chemistry. In view of this, electron induced scattering of molecules such as silane finds significance. This article reports a comprehensive study of electron impact cross sections for silane over a wide energy range. In particular, the emphasis is given in providing a complete dataset for various electron scattering events possible with silane. Such dataset is the need for the plasma modeling community. Moreover, literature survey shows that the cross section database for silane is fragmentary. To fill this void, we have computed the differential elastic, total, rotational excitation, and momentum transfer cross sections. Two formalisms that are reliable in their energy domain are employed to accomplish the task: the R-matrix method through QUANTEMOL-N at low incident energies and the spherical complex optical potential formalism at intermediate to high energies. Interestingly, the comparison of the present cross section exhibits a good concurrence with the previous data, wherever available.

  8. Investigation of the electron capture process in semiclassical plasma

    Directory of Open Access Journals (Sweden)

    Seisembayeva Madina M.

    2016-06-01

    Full Text Available In this work, the process of electron capture in partially ionized plasma is considered. Electron-atom interaction was described by the effective interaction potential, which takes into account the screening effect at large distances and the diffraction effect at the small distances. The results of numerical calculations of the electron capture radius, differential cross-section for different values of the coupling and density parameters are presented. The differential cross-section was obtained on the basis of perturbation theory and also by solving of the equation of motion of the projectile electron.

  9. Scattering processes and electrical conductivity of partially ionized hydrogen plasma

    Energy Technology Data Exchange (ETDEWEB)

    Ramazanov, T. [Fachbereich Physik, Universitaet Rostock, D-18051 Rostock (Germany); SRIETP, Al Farabi Kazakh National University, Tole bi, 96a, 480012, Almaty (Kazakhstan); Galiyev, K.; Dzhumagulova, K.N. [SRIETP, Al Farabi Kazakh National University, Tole bi, 96a, 480012, Almaty (Kazakhstan); Roepke, G.; Redmer, R. [Fachbereich Physik, Universitaet Rostock, D-18051 Rostock (Germany)

    2003-07-01

    We consider partially ionized hydrogen plasma for the density region n{sub e} = (10{sup 18} / 10{sup 22}) cm{sup -} {sup 3}. The cross sections for scattering processes between the particles are calculated within the partial wave method. Charged particles in the system (electrons, protons) interact via an effective potential that takes into account three-particle correlations. The Buckingham polarization potential is used to describe electron-atom and proton-atom interactions. The electrical conductivity is determined using the Chapman-Enskog method. The results are compared with other available data. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  10. Fabrication of La0.3Sr0.7CoO3 – thin layers on porous supports by a polymeric sol–gel process

    NARCIS (Netherlands)

    Chen, Chunhua; Bouwmeester, Henny J.M.; Kruidhof, Henk; Elshof, ten Johan E.; Burggraaf, Anthonie J.

    1996-01-01

    A polymeric sol–gel process was developed to fabricate porous thin layers of the perovskite-type La0.3Sr0.7CoO3 – for membrane applications. A spin-coating technique was used for deposition of the layer on porous -and -Al2O3 supports. Both supported and non-supported membranes were characterized by

  11. Polymeric microspheres with N-methyl-D-glucamine ligands for boron removal from water solution by adsorption-membrane filtration process.

    Science.gov (United States)

    Wolska, Joanna; Bryjak, Marek; Kabay, Nalan

    2010-08-01

    Polymeric microspheres with N-methyl-D-glucamine (NMDG) ligands have been tested in the adsorption-membrane filtration process for boron removal from aqueous solutions. The chelating resins were synthesized by reacting NMDG with the vinylbenzyl chloride-styrene-1,4-divinylbenzene (VBC/S/DVB) copolymer at the reflux temperature and in the microwave reactor. VBC/S/DVB spheres with a gel structure that contained 6 wt% DVB were obtained by membrane emulsification followed by suspension polymerization. By selecting the optimal emulsification and polymerization parameters, it was possible to obtain 25-microm-diameter particles with a narrow size distribution. Resins obtained by microwave modification showed the higher boron adsorption capacity.

  12. Plasma surface modification of polymers

    Science.gov (United States)

    Hirotsu, T.

    1980-01-01

    Thin plasma polymerization films are discussed from the viewpoint of simplicity in production stages. The application of selective, absorbent films and films used in selective permeability was tested. The types of surface modification of polymers discussed are: (1) plasma etching, (2) surface coating by plasma polymerized thin films, and (3) plasma activation surface graft polymerization.

  13. Monitoring and Improving the Reliability of Plasma Spray Processes

    Science.gov (United States)

    Mauer, Georg; Rauwald, Karl-Heinz; Mücke, Robert; Vaßen, Robert

    2017-06-01

    Monitoring and improving of process reliability are prevalent issues in thermal spray technology. They are intended to accomplish specific quality characteristics by controlling the process. For this, implicit approaches are in demand to rapidly conclude on relevant coating properties, i.e., they are not directly measured, but it is assumed that the monitored variables are in fact suggestive for them. Such monitoring can be performed in situ (during the running process) instead of measuring coating characteristics explicitly (directly) and ex situ (after the process). Implicit approaches can be based on extrinsic variables (set from outside) as well as on intrinsic parameters (internal, not directly adjustable) having specific advantages and disadvantages, each. In this work, the effects of atmospheric plasma spray process variables are systemized in process schemes. On this basis, different approaches to contribute to improved process reliability are described and assessed paying particular attention to in-flight particle diagnostics. Finally, a new test applying spray bead analysis is introduced and first results are presented.

  14. Real-Time Plasma Process Condition Sensing and Abnormal Process Detection

    Directory of Open Access Journals (Sweden)

    Ryan Yang

    2010-06-01

    Full Text Available The plasma process is often used in the fabrication of semiconductor wafers. However, due to the lack of real-time etching control, this may result in some unacceptable process performances and thus leads to significant waste and lower wafer yield. In order to maximize the product wafer yield, a timely and accurately process fault or abnormal detection in a plasma reactor is needed. Optical emission spectroscopy (OES is one of the most frequently used metrologies in in-situ process monitoring. Even though OES has the advantage of non-invasiveness, it is required to provide a huge amount of information. As a result, the data analysis of OES becomes a big challenge. To accomplish real-time detection, this work employed the sigma matching method technique, which is the time series of OES full spectrum intensity. First, the response model of a healthy plasma spectrum was developed. Then, we defined a matching rate as an indictor for comparing the difference between the tested wafers response and the health sigma model. The experimental results showed that this proposal method can detect process faults in real-time, even in plasma etching tools.

  15. Effect of impurities on kinetic transport processes in fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Braun, Stefanie

    2010-12-10

    Within the framework of this thesis, different problems arising in connection with impurities have been investigated. Collisional damping of zonal flows in tokamaks: Since the Coulomb collision frequency increases with increasing ion charge, heavy, highly charged impurities play an important role in this process. The effect of such impurities on the linear response of the plasma to an external potential perturbation, as caused by zonal flows, is calculated with analytical methods. In comparison with a pure plasma, the damping of the flows occurs, as expected, considerably faster; for experimentally relevant parameters, the enhancement exceeds the effective charge Z{sub eff} of the plasma. Impurity transport driven by microturbulence in tokamaks: With regard to impurities, it is especially important whether the resulting flows are directed inwards or outwards, since they are deleterious for core energy confinement on the one hand, but on the other hand help protecting plasma-facing components from too high energy fluxes in the edge region. A semi-analytical model is presented describing the resulting impurity fluxes and the stability boundary of the underlying mode. The main goal is to bridge the gap between, on the one hand, costly numerical simulations, which are applicable to a broad range of problems but yield scarcely traceable results, and, on the other hand, analytical theory, which might ease the interpretation of the results but is so far rather rudimentary. The model is based on analytical formulae whenever possible but resorts to a numerical treatment when the approximations necessary for an analytical solution would lead to a substantial distortion of the results. Both the direction of the impurity flux and the stability boundary are found to depend sensitively on the plasma parameters such as the impurity density and the temperature gradient. Pfirsch-Schlueter transport in stellarators: Due to geometry effects, collisional transport plays a much more

  16. Processing of bulk Al7075 alloy by spark plasma sintering

    Science.gov (United States)

    Málek, P.; Molnárová, O.; Cinert, J.; Lukáč, F.; Chráska, T.

    2017-02-01

    The main advantages of powder metallurgy processing route are the possibility to produce near-net-shape compacts and to minimize the finish machining and material loss. The main problem in particle consolidation process is to suppress porosity, to remove oxide layers, and to retain the microstructure of powder materials. Spark plasma sintering (SPS) combines concurrent uniaxial pressure and direct heating by a pulsed DC current. Sintering occurs at relatively low temperatures for a short time and does not influence significantly the microstructure in the interiors of original powder particles. The efficiency of SPS in producing compacts with low porosity might be dependent on the distribution of particle size in original powder material. The gas atomized Al7075 powder was sieved to several charges and then sintered by SPS. Microstructure of sintered compacts was studied by light and scanning electron microscopy. The phase composition was investigated using X-ray diffraction. The mechanical behaviour was tested by bending tests.

  17. Dusty plasma processes in Earth's polar summer mesosphere

    Science.gov (United States)

    Popel, S. I.; Dubinsky, A. Yu.; Dubinsky

    2013-08-01

    A self-consistent model for the description of dusty plasma structures, such as noctilucent clouds (NLC) and polar mesosphere summer echoes (PMSE), which are frequently grouped together under the common term polar mesospheric clouds, is presented. The model takes into account the processes of condensation of water vapor, ionization, recombination, action of solar radiation, sedimentation, dust particle growth, dust particle charging, electric fields, etc. Using the model, we explain the basic data of observations on the behavior of charged component in polar summer mesosphere. Furthermore, we show the influence of initial distributions of fine particles as well as that of the processes of condensation and water molecule absorption by fine particles on the formation of NLC and PMSE. We also illustrate the possibility of the formation of layered structure and sharp boundaries of NLC.

  18. Enhanced mechanical properties of low-surface energy thin films by simultaneous plasma polymerization of fluorine and epoxy containing polymers

    Science.gov (United States)

    Karaman, Mustafa; Uçar, Tuba

    2016-01-01

    Thin films of poly(2,2,3,4,4,4 hexafluorobutyl acrylate-glycidyl methacrylate) (P(HFBA-GMA) were deposited on different surfaces using an inductively coupled RF plasma reactor. Fluorinated polymer was used to impart hydrophobicity, whereas epoxy polymer was used for improved durability. The deposition at a low plasma power and temperature was suitable for the functionalization of fragile surfaces such as textile fabrics. The coated rough textile surfaces were found to be superhydrophobic with water contact angles greater than 150° due to the high retention of long fluorinated side chains. The hydrophobicity of the surfaces was observed to be stable after many exposures to ultrasonification tests, which is attributed to the mechanical durability of the films due to their epoxide functionality. FTIR and XPS analyses of the deposited films confirmed that the epoxide functionality of the polymers increased with increasing glycidyl methacrylate fraction in the reactor inlet. The modulus and hardness values of the films also increase with increasing epoxide functionality.

  19. Enhanced mechanical properties of low-surface energy thin films by simultaneous plasma polymerization of fluorine and epoxy containing polymers

    Energy Technology Data Exchange (ETDEWEB)

    Karaman, Mustafa, E-mail: karamanm@selcuk.edu.tr [Department of Chemical Engineering, Selçuk University, Konya, 42075 (Turkey); Advanced Technology Research & Application Center, Selçuk University, Konya, 42075 (Turkey); Uçar, Tuba [Department of Chemical Engineering, Selçuk University, Konya, 42075 (Turkey)

    2016-01-30

    Graphical abstract: - Highlights: • Thin films of poly(hexafluorobutyl acrylate-glycidyl methacrylate) can be deposited by PECVD. • The coated surfaces are hydrophobic due to the long fluorinated side chains. • The hydrophobicity of the coating is observed to be stable under harsh conditions. • Film durability is attributed to the mechanical strength of the films due to their epoxide functionality. - Abstract: Thin films of poly(2,2,3,4,4,4 hexafluorobutyl acrylate-glycidyl methacrylate) (P(HFBA-GMA) were deposited on different surfaces using an inductively coupled RF plasma reactor. Fluorinated polymer was used to impart hydrophobicity, whereas epoxy polymer was used for improved durability. The deposition at a low plasma power and temperature was suitable for the functionalization of fragile surfaces such as textile fabrics. The coated rough textile surfaces were found to be superhydrophobic with water contact angles greater than 150° due to the high retention of long fluorinated side chains. The hydrophobicity of the surfaces was observed to be stable after many exposures to ultrasonification tests, which is attributed to the mechanical durability of the films due to their epoxide functionality. FTIR and XPS analyses of the deposited films confirmed that the epoxide functionality of the polymers increased with increasing glycidyl methacrylate fraction in the reactor inlet. The modulus and hardness values of the films also increase with increasing epoxide functionality.

  20. 氯乙烯悬浮聚合原辅材料质量对聚合工艺和产品质量的影响%Influences of qualities of raw and auxiliary materials for suspension polymerization of vinyl chloride on polymerization process and product quality

    Institute of Scientific and Technical Information of China (English)

    吴宝娈; 齐树东; 张春明

    2011-01-01

    Requirements on raw and auxiliary materials for the suspension polymerization of vinyl chloride were introduced as well as their influences on the polymerization process and product quality.%介绍了氯乙烯悬浮聚合原辅材料质量要求及其对聚合工艺和产品质量的影响。

  1. Sensor-property-NDE relationships of polymeric composites processed through resin infusion

    Science.gov (United States)

    Vaidya, U. K.; Mohamed, H.; Fotedar, K.; Haque, A.; Mahfuz, H.; Jeelani, S.

    1998-04-01

    Liquid molding manufacturing techniques including vacuum assisted resin infusion molding (VARIM) and resin transfer molding (RTM) offer low cost alternatives for producing composites. The cure characteristics of these composites are monitored by dielectric tool mount sensors in an RTM process, however embedded inter-digitated electrode sensors (IDEX) are becoming popular in the VARIM process. The IDEX sensors remain an integral part of the composite after cure. In this paper, first the response of the dielectric IDEX sensors to various resin systems in neat resin stage as well as in the resin matrix composite is presented. The paper then investigates the mechanical performance of the composites containing IDEX sensors for various loading situations involving interlaminar shear strength, low velocity impact and high strain rate testing. Ultrasonic nondestructive evaluation conducted is also presented.

  2. Molecular Optics Nonlinear Optical Processes in Organic and Polymeric Crystals and Films. Part 2

    Science.gov (United States)

    1991-11-01

    susceptibility gamma ijkl(-omega 4; omega 1, omega 2, omega 3 ) demonstrate that the microscopic origin of the nonresonant third order nonlinear optical...interaction calculations of gamma jkl(-omega 4; omega 1, omega 2, omega 3 ) for the archetypal class of quasi-one dimensional conjugated structures...largest of the two dominant, competing virtual excitation processes that determine gamma ijkl(- omega 4; omega 1, omega 2, omega 3 ). It is also found in

  3. Nonlinear Optical Properties of Organic and Polymeric Thin Film Materials of Potential for Microgravity Processing Studies

    Science.gov (United States)

    Abdeldayem, Hossin; Frazier, Donald O.; Paley, Mark S.; Penn, Benjamin; Witherow, William K.; Bank, Curtis; Shields, Angela; Hicks, Rosline; Ashley, Paul R.

    1996-01-01

    In this paper, we will take a closer look at the state of the art of polydiacetylene, and metal-free phthalocyanine films, in view of the microgravity impact on their optical properties, their nonlinear optical properties and their potential advantages for integrated optics. These materials have many attractive features with regard to their use in integrated optical circuits and optical switching. Thin films of these materials processed in microgravity environment show enhanced optical quality and better molecular alignment than those processed in unit gravity. Our studies of these materials indicate that microgravity can play a major role in integrated optics technology. Polydiacetylene films are produced by UV irradiation of monomer solution through an optical window. This novel technique of forming polydiacetylene thin films has been modified for constructing sophisticated micro-structure integrated optical patterns using a pre-programmed UV-Laser beam. Wave guiding through these thin films by the prism coupler technique has been demonstrated. The third order nonlinear parameters of these films have been evaluated. Metal-free phthalocyanine films of good optical quality are processed in our laboratories by vapor deposition technique. Initial studies on these films indicate that they have excellent chemical, laser, and environmental stability. They have large nonlinear optical parameters and show intrinsic optical bistability. This bistability is essential for optical logic gates and optical switching applications. Waveguiding and device making investigations of these materials are underway.

  4. The covalent immobilization of heparin to pulsed-plasma polymeric allylamine films on 316L stainless steel and the resulting effects on hemocompatibility.

    Science.gov (United States)

    Yang, Zhilu; Wang, Jin; Luo, Rifang; Maitz, Manfred F; Jing, Fengjuan; Sun, Hong; Huang, Nan

    2010-03-01

    For an improved hemocompatibility of 316L stainless steel (SS), we develop a facile and effective approach to fabricating a pulsed-plasma polymeric allylamine (P-PPAm) film that possesses a high cross-linking degree and a high density of amine groups, which is used for subsequent bonding of heparin. The P-PPAm film as a stent coating shows good resistance to the deformation behavior of compression and expansion of a stent. Using deionized water as an aging medium, it is demonstrated that the heparin-immobilized P-PPAm (Hep-P-PPAm) surface has a good retention of heparin. The systematic in vitro hemocompatibility evaluation reveals lower platelet adhesion, platelet activation and fibrinogen activation on the Hep-P-PPAm surface, and the activated partial thromboplastin time prolongs for about 15 s compared with 316L SS. The P-PPAm surface significantly promotes adhesion and proliferation of endothelial cells (ECs). For the Hep-P-PPAm, although EC adhesion and proliferation is slightly suppressed initially, after cultivation for 3 days, the growth behavior of ECs is remarkably improved over 316L SS. In vivo results indicate that the Hep-P-PPAm surface successfully restrain thrombus formation by growing a homogeneous and intact shuttle-like endothelium on its surface. The Hep-P-PPAm modified 316L SS shows a promising application for vascular devices.

  5. In situ synthesis of silver nanoparticles on the cotton fabrics modified by plasma induced vapor phase graft polymerization of acrylic acid for durable multifunction

    Science.gov (United States)

    Wang, C. X.; Ren, Y.; Lv, J. C.; Zhou, Q. Q.; Ma, Z. P.; Qi, Z. M.; Chen, J. Y.; Liu, G. L.; Gao, D. W.; Lu, Z. Q.; Zhang, W.; Jin, L. M.

    2017-02-01

    A practical and ecological method for preparing the multifunctional cotton fabrics with excellent laundering durability was explored. Cotton fabrics were modified by plasma induced vapor phase graft polymerization (PIVPGP) of acrylic acid (AA) and subsequently silver nanoparticles (AgNPs) were in situ synthesized on the treated cotton fabrics. The AgNP loaded cotton fabrics were characterized by scanning electron microscope (SEM), energy dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), antibacterial activity, self-cleaning activity, thermal stability and laundering durability, respectively. SEM observation and EDX, XPS and XRD analysis demonstrated the much more AgNPs deposition on the cotton fabrics modified by PIVPGP of AA. The AgNP loaded cotton fabrics also exhibited better antibacterial activity, self-cleaning activity, thermal stability and laundering durability. It was concluded that the surface modification of the cotton fabrics by PIVPGP of AA could increase the loading efficiency and binding fastness of AgNPs on the treated cotton fabrics, which could fabricate the cotton fabrics with durable multifunction. In addition, the mechanism of in situ synthesis of AgNPs on the cotton fabrics modified by PIVPGP of AA was proposed.

  6. Thermo-responsive wound dressings by grafting chitosan and poly(N-isopropylacrylamide) to plasma-induced graft polymerization modified non-woven fabrics

    Science.gov (United States)

    Chen, Jyh-Ping; Kuo, Chang-Yi; Lee, Wen-Li

    2012-12-01

    To obtain a chitosan wound dressings with temperature-responsive characteristics, polypropylene (PP) non-woven fabric (NWF) was modified by direct current pulsed oxygen plasma-induced grafting polymerization of acrylic acid (AAc) to improve hydrophilicity and to introduce carboxylic acid groups. Conjugation of chitosan and poly(N-isopropylacrylamide) (PNIPAAm) followed by using water-soluble carbodiimide as a coupling agent to form a novel bigraft PP-g-chitosan-g-PNIPAAm wound dressing. The amount of chitosan and PNIPAAm grafted to PP-g-chitosan-g-PNIPAAm were 83.0 ± 4.6 μg/cm2 and 189.5 ± 8.2 μg/cm2, respectively. The surface chemical composition and microstructure of the NWF were studied by electron spectroscopy for chemical analysis (ESCA) and scanning electron microscopy (SEM). The linkages between AAc, chitosan, and PNIPAAm were confirmed with the formation of amide bonds. Physical properties of the NWF were characterized and potentials of these NWFs as wound dressings were evaluated using SD rat as the animal model. NWFs contained PNIPAAm were better than those contained only chitosan in wound healing rates and the wound areas covered by PP-g-chitosan-g-PNIPAAm wound dressings healed completely in 17 days.

  7. Paraffin processing of stented arteries using a postfixation dissolution of metallic and polymeric stents.

    Science.gov (United States)

    Fishbein, Ilia; Welch, Tre; Guerrero, David T; Alferiev, Ivan S; Adamo, Richard F; Chorny, Michael; Gupte, Rohit K; Tang, Yanqing; Levy, Robert J

    Studying the morphology of the arterial response to endovascular stent implantation requires embedding the explanted stented artery in rigid materials such as poly(methyl methacrylate) to enable sectioning through both the in situ stent and the arterial wall, thus maintaining the proper anatomic relationships. This is a laborious, time-consuming process. Moreover, the technical quality of stained plastic sections is typically suboptimal and, in some cases, precludes immunohistochemical analysis. Here we describe a novel technique for dissolution of metallic and plastic stents that is compatible with subsequent embedding of "destented" arteries in paraffin, fine sectioning, major staining protocols, and immunohistochemistry.

  8. Analysis of suprathermal nuclear processes in the solar core plasma

    Science.gov (United States)

    Voronchev, Victor T.; Nakao, Yasuyuki; Watanabe, Yukinobu

    2017-04-01

    A consistent model for the description of suprathermal processes in the solar core plasma naturally triggered by fast particles generated in exoergic nuclear reactions is formulated. This model, based on the formalism of in-flight reaction probability, operates with different methods of treating particle slow-down in the plasma, and allows for the influence of electron degeneracy and electron screening on processes in the matter. The model is applied to examine slowing-down of 8.7 MeV α-particles produced in the {}7{Li}(p,α )α reaction of the pp chain, and to analyze suprathermal processes in the solar CNO cycle induced by them. Particular attention is paid to the suprathermal {}14{{N}}{(α ,{{p}})}17{{O}} reaction unappreciated in standard solar model simulations. It is found that an appreciable non-standard (α ,p) nuclear flow due to this reaction appears in the matter and modifies running of the CNO cycle in ∼95% of the solar core region. In this region at R> 0.1{R}ȯ , normal branching of nuclear flow {}14{{N}}≤ftarrow {}17{{O}}\\to {(}18{{F}})\\to {}18{{O}} transforms to abnormal sequential flow {}14{{N}}\\to {}17{{O}}\\to {(}18{{F}})\\to {}18{{O}}, altering some element abundances. In particular, nuclear network calculations reveal that in the outer core the abundances of 17O and 18O isotopes can increase by a factor of 20 as compared with standard estimates. A conjecture is made that other CNO suprathermal (α ,p) reactions may also affect abundances of CNO elements, including those generating solar neutrinos.

  9. Secondary electron emission from plasma processed accelerating cavity grade niobium

    Science.gov (United States)

    Basovic, Milos

    by different techniques. Specifically, this work provides the results of SEY from the plasma cleaned cavity grade niobium (Nb) samples. Pure niobium is currently the material of choice for the fabrication of Superconducting Radio Frequency (SRF) cavities. The effect of plasma processing with two different gases will be examined in two groups of samples. The first group of samples is made from cavity grade niobium. The second group of samples is made from the same material, but include a welded joint made by electron beam welding, since in niobium SRF cavities the peak electric and magnetic field are seen in close proximity to the welded joints. Both groups of samples will be exposed to nitrogen (N2) and a mixture of argon with oxygen (Ar/O2) plasma. It is the goal of this research to determine the SEY on these two groups of samples before and after plasma processing as a function of the energy of primary electrons. The SEY as a function of the angle of incidence of the primary electrons is tested on the samples treated with Ar/O2 plasma.

  10. Secondary Electron Emission from Plasma Processed Accelerating Cavity Grade Niobium

    Energy Technology Data Exchange (ETDEWEB)

    Basovic, Milos [Old Dominion Univ., Norfolk, VA (United States)

    2016-05-01

    by different techniques. Specifically, this work provides the results of SEY from the plasma cleaned cavity grade niobium (Nb) samples. Pure niobium is currently the material of choice for the fabrication of Superconducting Radio Frequency (SRF) cavities. The effect of plasma processing with two different gases will be examined in two groups of samples. The first group of samples is made from cavity grade niobium. The second group of samples is made from the same material, but include a welded joint made by electron beam welding, since in niobium SRF cavities the peak electric and magnetic field are seen in close proximity to the welded joints. Both groups of samples will be exposed to nitrogen (N2) and a mixture of argon with oxygen (Ar/O2) plasma. It is the goal of this research to determine the SEY on these two groups of samples before and after plasma processing as a function of the energy of primary electrons. The SEY as a function of the angle of incidence of the primary electrons is tested on the samples treated with Ar/O2 plasma.

  11. A numerical approach to drying process of hygroscopic polymeric granulates with different drying configurations and parameter comparison

    Science.gov (United States)

    Mahbub, A. M. Ishtiaque; Mawa, Zannatul

    2017-06-01

    Some polymers tend to possess affinity with water and eventually, absorb significant moisture content from the surrounding air, causing difficulties during their industrial processing. Drying of these hygroscopic polymers, therefore, plays a vital role in their usability in industrial applications. In this work, the drying kinetics of the polymeric granulates is numerically formulated and the influence of different parameters pertaining to the drying procedure has been investigated. Backward Euler or implicit algorithm has been considered for solving the second order partial differential heat and mass transfer equations for simulating the drying kinetics of Polyamide 6 (PA-6). At first, the conduction of heat from the granulate surface towards the core was formulated using one dimensional transient heat conduction law and corresponding diffusion coefficients were determined using Arrhenius diffusion model. Afterwards, the migration of moisture from the granulate core towards the surface has been calculated using Fick's second law of diffusion. The data obtained from the single polymer granulate was then used to calculate the amount of moisture removed and the drying rate. The numerical results showed similitude with the experimental data obtained from the literature, although deviated quantitatively. To investigate the influence of different parameters on the drying process, different cases with varying drying air temperature, granulate radius and initial moisture content were compared. The numerical analysis qualitatively predicted all the dependencies to be expected. With higher drying air temperature, drying rate was observed to be faster and with higher granulate radius, drying rate was slower. With better approximations of the applied parameters and algorithms, the accuracy of the developed numerical model could be improved and used as a prediction tool for the drying process of polymer samples with reasonable tolerance.

  12. Sustained-release microsphere formulation containing an agrochemical by polyurethane polymerization during an agitation granulation process.

    Science.gov (United States)

    Terada, Takatoshi; Tagami, Manabu; Ohtsubo, Toshiro; Iwao, Yasunori; Noguchi, Shuji; Itai, Shigeru

    2016-07-25

    In this report, a new solventless microencapsulation method by synthesizing polyurethane (PU) from polyol and isocyanate during an agglomeration process in a high-speed mixing apparatus was developed. Clothianidin (CTD), which is a neonicotinoid insecticide and highly effective against a wide variety of insect pests, was used as the model compound. The microencapsulated samples covered with PU (CTD microspheres) had a median diameter of dispersed in PU. Although voids appeared in the CTD microspheres after CTD release, the spherical shape of the microspheres remained stable and no change in its framework was observed. The experimental release data were highly consistent with the Baker-Lonsdale model derived from drug release of spherical monolithic dispersions and consistent with the computed tomography measurements.

  13. Spatial control of processing plasmas in a multicusp plasma source equipped with a movable magnetic filter

    Energy Technology Data Exchange (ETDEWEB)

    Fukumasa, O.; Naitou, H.; Sakiyama, S. (Yamaguchi Univ., Yamaguchi (Japan))

    1991-12-20

    The plasma chemical vapor deposition (p-CVD) method has been used in the preparation of various sorts of thin films such as hydrogenated amorphous silicon films and hydrogenated amorphous carbon films, etc. and the application feasibility of a magnetically filtered multicusp plasma source has been studied. In this paper, it is confirmed that plasma parameters (H {sub 2} - ch {sub 4} or Ar-CH {sub 4} plasmas) are spatially well controlled by using both a movable magnetic filter and a plasma grid. Plasma parameters change sharply across the magnetic filter at any filter position and the whole plasma is divided clearly into the region of source plasma with high-energy electrons and the region of diffused plasma without high-energy electrons. Concerning the role of the magnetic filter which reflects preferentially high-energy electrons, a study is made through computer simulation. 7 refs., 9 figs.

  14. Catalyst materials based on plasma-processed alumina nanopowder

    Directory of Open Access Journals (Sweden)

    Dubencovs Konstantins

    2012-01-01

    Full Text Available A platinum catalyst for glycerol oxidation by molecular oxygen has been developed applying the extractive-pyrolytic method and using, as a support, a fine alumina powder with an average particle size of 30-60 nm processed by plasma technology. The extractive-pyrolytic method (EPM allows affixing small amounts of catalytic metals (1-5% with the particle size ranging from several nanometers to several tens of nanometers onto the surface of the support. The prepared material - 4.8 wt. % platinum on nano-sized alumina - can be used as a catalyst for glycerol oxidation by oxygen with conversion up to 84%, in order to produce some organic acids (glyceric and lactic acid with a selectivity of about 60%.

  15. Monocyte/macrophage and protein interactions with non-fouling plasma polymerized tetraglyme and chemically modified polystyrene surfaces: In vitro and in vivo studies

    Science.gov (United States)

    Shen, Mingchao

    2001-07-01

    Biomaterials become encapsulated by fibrous tissues after implantation in soft tissues. Monocytes and macrophages are believed to play important roles in this response. The hypothesis tested in this dissertation is that material surface chemistry determines the amount of adsorbed proteins, which mediate monocyte adhesion, activation, and the foreign body response. On chemically modified polystyrene surfaces, monocyte adhesion in vitro was promoted by preadsorbed fibrinogen, fibronectin, and IgG, and increased with increasing amount of adsorbed fibrinogen. Adsorbed proteins and material surface chemistry mediated monocyte activation. TNFalpha release, procoagulant activity, and multinucleated foreign body giant cell (FBGC) formation was at least two-fold higher on IgG than other protein adsorbed surfaces. Adsorbed IgG and fibrinogen triggered monocyte intracellular calcium changes. FBGC formation was the highest on the hydrophobic polystyrene surface. Materials that greatly reduce non-specific protein adsorption may reduce the foreign body response to implanted materials. Radio-frequency plasma polymerized tetraglyme (CH3O(CH2CH2O)4CH 3) surfaces contained PEO-like chemical species and reduced fibrinogen adsorption to less than 10 ng/cm2. Monocyte adhesion to tetraglyme in vitro was also greatly reduced. Monocyte adhesion correlated linearly to the amount of adsorbed fibrinogen on a series of tetraglyme surfaces deposited at different plasma powers. Multivariate analysis using partial least squares regression identified the key surface spectra variables from electron spectroscopy for chemical analysis (ESCA) and time of flight secondary ion mass spectrometry (ToF-SIMS) that contributed to the non-fouling properties of tetraglyme. However, leukocyte adhesion to surfaces implanted subcutaneously in mice for 1 or 28 days did not correlate with protein adsorption and was higher on tetraglyme than the FEP control. Fibrous encapsulation to tetraglyme implanted for 28 days

  16. Ni/Al Intermetallics Plasma Transferred Arc Processing

    Institute of Scientific and Technical Information of China (English)

    VeronicaA.B.Almeida; AnaSofiaC.M.D'Oliveira

    2004-01-01

    In-situ alloy development during surface processing allows for a limitless materials selection to protect components exposed to severe service conditions. In fact surface alloying offers the possibility to strengthen surface components with alloys that would not be possible to process otherwise. This work used Plasma transferred arc (PTA) hardfacing for surface alloying. Different amounts of aluminium powder, 5-25%, were added to a Ni based superalloy, from Hastealloy C family, in the atomized form. The mixture was homogeneized in a ball mill and PTA deposited on carbon steel substrate. The influence of different processing parameters on the final surface alloy was evaluated as current intensity and depositing velocity were varied. Coatings were characterized by optical and scanning electronic microscopy, X-ray diffraction and Vickers microhardness profiles, under a 500g load. Results showed that PTA hardfacing is an adequate surface alloying. For the conditions tested increasing hardness was obtained by solid solution for the lower amounts of Al added and due to the new intermetallic phases for the richer Al mixture.

  17. Ni/Al Intermetallics Plasma Transferred Arc Processing

    Institute of Scientific and Technical Information of China (English)

    Ver(o)nica A. B. Almeida; Ana Sofia C. M. D'Oliveira

    2004-01-01

    In-situ alloy development during surface processing allows for a limitless materials selection to protect components exposed to severe service conditions. In fact surface alloying offers the possibility to strengthen surface components with alloys that would not be possible to process otherwise. This work used Plasma transferred arc (PTA) hardfacing for surface alloying. Different amounts of aluminium powder, 5-25%, were added to a Ni based superalloy, from Hastealloy C family, in the atomized form. The mixture was homogeneized in a ball mill and PTA deposited on carbon steel substrate. The influence of different processing parameters on the final surface alloy was evaluated as current intensity and depositing velocity were varied. Coatings were characterized by optical and scanning electronic microscopy, X-ray diffraction and Vickers microhardness profiles, under a 500g load. Results showed that PTA hardfacing is an adequate surface alloying. For the conditions tested increasing hardness was obtained by solid solution for the lower amounts of Al added and due to the new intermetallic phases for the richer Al mixture.

  18. Production of stable isotopes utilizing the plasma separation process

    Science.gov (United States)

    Bigelow, T. S.; Tarallo, F. J.; Stevenson, N. R.

    2005-12-01

    A plasma separation process (PSP) is being operated at Theragenics Corporation's®, Oak Ridge, TN, facility for the enrichment of stable isotopes. The PSP utilizes ion cyclotron mass discrimination to separate isotopes on a relatively large scale. With a few exceptions, nearly any metallic element could be processed with PSP. Output isotope enrichment factor depends on natural abundance and mass separation and can be fairly high in some cases. The Theragenics™ PSP facility is believed to be the only such process currently in operation. This system was developed and formerly operated under the US Department of Energy Advanced Isotope Separation program. Theragenics™ also has a laboratory at the PSP site capable of harvesting the isotopes from the process and a mass spectrometer system for analyzing enrichment and product purity. Since becoming operational in 2002, Theragenics™ has utilized the PSP to separate isotopes of several elements including: dysprosium, erbium, gadolinium, molybdenum and nickel. Currently, Theragenics™ is using the PSP for the separation of 102Pd, which is used as precursor for the production of 103Pd. The 103Pd radioisotope is the active ingredient in TheraSeed®, which is used in the treatment of early stage prostate cancer and being investigated for other medical applications. New industrial, medical and research applications are being investigated for isotopes that can be enriched on the PSP. Pre-enrichment of accelerator or reactor targets offers improved radioisotope production. Theragenics operates 14 cyclotrons for proton activation and has access to HFIR at ORNL for neutron activation of radioisotopes.

  19. Thermal compression chip interconnection using organic solderability preservative etched substrate by plasma processing.

    Science.gov (United States)

    Cho, Sung-Won; Choi, JoonYoung; Chung, Chin-Wook

    2014-12-01

    The solderability of copper organic solderbility preservative (CuOSP) finished substrate was enhanced by the plasma etching. To improve the solderability of TC interconnection with the CuOSP finished substrate, the plasma etching process is used. An Oxygen-Hydrogen plasma treatment process is performed to remove OSP material. To prevent the oxidation by oxygen plasma treatment, hydrogen reducing process is also performed before TC interconnection process. The thickness of OSP material after plasma etching is measured by optical reflection method and the component analysis by Auger Electron Spectroscopy is performed. From the lowered thickness, the bonding force of TC interconnection after OSP etching process is lowered. Also the electrical open/short test was performed after assembling the completed semiconductor packaging. The improved yield due to the plasma etching process is achieved.

  20. Research progress of laser welding process dynamic monitoring technology based on plasma characteristics signal

    Directory of Open Access Journals (Sweden)

    Teng WANG

    2017-02-01

    Full Text Available During the high-power laser welding process, plasmas are induced by the evaporation of metal under laser radiation, which can affect the coupling of laser energy and the workpiece, and ultimately impact on the reliability of laser welding quality and process directly. The research of laser-induced plasma is a focus in high-power deep penetration welding field, which provides a promising research area for realizing the automation of welding process quality inspection. In recent years, the research of laser welding process dynamic monitoring technology based on plasma characteristics is mainly in two aspects, namely the research of plasma signal detection and the research of laser welding process modeling. The laser-induced plasma in the laser welding is introduced, and the related research of laser welding process dynamic monitoring technology based on plasma characteristics at home and abroad is analyzed. The current problems in the field are summarized, and the future development trend is put forward.

  1. Nova tocha de plasma híbrida para o processamento de materiais New hybrid plasma torch for materials processing

    Directory of Open Access Journals (Sweden)

    Richard Thomas Lermen

    2012-12-01

    Full Text Available O principal objetivo deste artigo foi apresentar um novo dispositivo para o processamento de materiais. Ele consiste em uma tocha de plasma híbrida, a qual é caracterizada pela formação simultânea de dois arcos plasma em apenas um dispositivo, gerando jato (de plasma com elevada densidade de energia. A tocha foi submetida aos seguintes testes experimentais: de funcionamento para verificar possíveis problemas de projeto e seus limites de operação; de caracterização, consistindo em determinar o comprimento do jato de plasma; de sua viabilidade para processamento de materiais (soldagem e corte. Com base nestes testes iniciais, alguns problemas de isolamento elétrico e térmico foram encontrados e resolvidos. Quanto aos resultados dos testes de caracterização, os parâmetros de funcionamento da tocha de plasma híbrida apresentaram influência significativa sobre o comprimento do jato de plasma. Os resultados obtidos nos testes de processamento de materiais foram satisfatórios, ou seja, é possível realizar soldagem e corte com esta tocha de plasma híbrida.The main aim of this paper was to present a new device for materials processing. It consist of a hybrid plasma torch which is characterized by the simultaneous formation of two plasma arcs in one device only, generating a (plasma jet with high energy density. The torch was submitted to the following trials: of operation to identify possible design problems and its operational torch limits; of characterization, consisting in plasma jet length determination; and of viability for materials processing (welding and cutting. Based on these initial trials, some electrical and thermal insulation problems were found and solved. Concerning the results of the characterization trials, the hybrid plasma torch parameters had a significant influence over the plasma jet length. The results obtained in the materials processing trials were satisfactory, i.e., it is possible to carry out welding and

  2. On the Way to Improve the Environmental Benignity of Chemical Processes: Novel Catalysts for a Polymerization Process

    Directory of Open Access Journals (Sweden)

    Silvana F. Rach

    2009-03-01

    Full Text Available An example for a process that can, in principle, be improved by the application of a catalyst is the synthesis of poly(2-methyl-propenes (“polyisobutenes”, which are important for numerous industrial applications. Each year several 100,000 t are produced. The production of low-molecular weight polyisobutenes by means of cationic initiation by an excess of Lewis acids is well established. Typically, these initiators require the usage of solvents like chloroform, dichloromethane and ethylene and temperatures far below 0 °C (–100 °C in the case of ethylene as solvent. Solvent stabilized transition metal complexes with weakly coordinating counter anions overcome these drawbacks and thus are not only more efficient, but also more environmentally benign: they can be applied at ambient temperature and in non chlorinated solvents at low concentrations.

  3. Highly permselective membrane surface modification by cold plasma-induced grafting polymerization of molecularly imprinted polymer for recognition of pyrethroid insecticides in fish.

    Science.gov (United States)

    Zhang, Rongrong; Guo, Xiaoqing; Shi, Xizhi; Sun, Aili; Wang, Lin; Xiao, Tingting; Tang, Zigang; Pan, Daodong; Li, Dexiang; Chen, Jiong

    2014-12-02

    Specific molecularly imprinted membranes (MIMs) for pyrethroid insecticides were developed and characterized for the first time in this study by cold plasma-induced grafting polymerization using methacrylic acid as a functional monomer and cypermethrin (CYP) as a template. The nonimprinted membranes (NIMs) were also synthesized using the same procedure without the template. Meanwhile, AFM, XPS, ATR-FTIR, contact angle, and permselectivity experiments were conducted to elucidate the imprinting and recognition properties of MIMs. Results demonstrated that MIMs exhibited excellent imprinting effect and high permselectivity. A molecularly imprinted-membrane-assisted solvent extraction (MI-MASE) method based on the MIMs was established. The operating conditions were optimized for group-selective extraction of the five pyrethroid insecticides. Compared with NIMs, higher extraction recoveries (83.8% to 100.6%) of the five pyrethroid insecticides by gas chromatography-electron capture detector (GC-ECD) were obtained using MIMs at three spiked levels in fish samples; the RSD values were lower than 8.3%. The limits of detection (LOD) and quantification (LOQ) defined as the concentrations at which the signal-to-noise (S/N) ratio is 3:1 and 10:1, respectively, were in the range of 0.26 to 0.42 μg/kg and 0.77 to 1.27 μg/kg, respectively. No matrix effect of the developed MI-MASE was observed by gas chromatography/tandem mass spectrometry (GC/MS/MS). These results demonstrated a highly selective, efficient, and environment-friendly MI-MASE technique for preconcentration and purification of pyrethroid insecticides from seafood, followed by GC-ECD and GC/MS/MS. The excellent applicability and potential of MI-MASE for routine monitoring of pyrethroid pesticides in food samples has also been confirmed.

  4. Thermo-responsive wound dressings by grafting chitosan and poly(N-isopropylacrylamide) to plasma-induced graft polymerization modified non-woven fabrics

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jyh-Ping, E-mail: jpchen@mail.cgu.edu.tw [Department of Chemical and Materials Engineering, Chang Gung University, 259 Wen Hwa 1st Rd., Kwei-San, Taoyuan 333, Taiwan (China); Kuo, Chang-Yi; Lee, Wen-Li [Department of Chemical and Materials Engineering, Chang Gung University, 259 Wen Hwa 1st Rd., Kwei-San, Taoyuan 333, Taiwan (China)

    2012-12-01

    Highlights: Black-Right-Pointing-Pointer Poly(N-isopropylacrylamide) and chitosan were grafted to polypropylene non-wovens. Black-Right-Pointing-Pointer An easily stripped off thermo-responsive wound dressing was developed. Black-Right-Pointing-Pointer The wound dressing is biocompatible, has antibacterial and wound healing abilities. Black-Right-Pointing-Pointer The bigraft non-woven will be a potential wound dressing for biomedical use. - Abstract: To obtain a chitosan wound dressings with temperature-responsive characteristics, polypropylene (PP) non-woven fabric (NWF) was modified by direct current pulsed oxygen plasma-induced grafting polymerization of acrylic acid (AAc) to improve hydrophilicity and to introduce carboxylic acid groups. Conjugation of chitosan and poly(N-isopropylacrylamide) (PNIPAAm) followed by using water-soluble carbodiimide as a coupling agent to form a novel bigraft PP-g-chitosan-g-PNIPAAm wound dressing. The amount of chitosan and PNIPAAm grafted to PP-g-chitosan-g-PNIPAAm were 83.0 {+-} 4.6 {mu}g/cm{sup 2} and 189.5 {+-} 8.2 {mu}g/cm{sup 2}, respectively. The surface chemical composition and microstructure of the NWF were studied by electron spectroscopy for chemical analysis (ESCA) and scanning electron microscopy (SEM). The linkages between AAc, chitosan, and PNIPAAm were confirmed with the formation of amide bonds. Physical properties of the NWF were characterized and potentials of these NWFs as wound dressings were evaluated using SD rat as the animal model. NWFs contained PNIPAAm were better than those contained only chitosan in wound healing rates and the wound areas covered by PP-g-chitosan-g-PNIPAAm wound dressings healed completely in 17 days.

  5. Imaging of the Staphylococcus aureus Inactivation Process Induced by a Multigas Plasma Jet.

    Science.gov (United States)

    Takamatsu, Toshihiro; Kawano, Hiroaki; Sasaki, Yota; Uehara, Kodai; Miyahara, Hidekazu; Matsumura, Yuriko; Iwasawa, Atsuo; Azuma, Takeshi; Okino, Akitoshi

    2016-12-01

    To identify mechanisms underlying the bacterial inactivation process by atmospheric nonthermal plasma using a unique plasma jet that can generate various gas plasmas, Staphylococcus aureus were irradiated with carbon dioxide plasma, which produces a large amount of singlet oxygens, and nitrogen plasma, which produces a large amount of OH radicals. And damaged areas of plasma-treated bacteria were observed by field emission scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. As a result, bacteria were damaged by both gas plasmas, but the site of damage differed according to gas species. Therefore, it suggests that singlet oxygen generated by carbon dioxide plasma or other reactive species caused by singlet oxygen contributes to the damage of internal structures of bacteria through the cell wall and membrane, and OH radicals generated by nitrogen plasma or other reactive species derived from OH radicals contribute to damage of the cell wall and membrane.

  6. Transferred plasma jet from a dielectric barrier discharge for processing of poly(dimethylsiloxane) surfaces

    CERN Document Server

    Nascimento, Fellype do; Canesqui, Mara A; Moshkalev, Stanislav

    2016-01-01

    In this work we studied processing of poly(dimethylsiloxane) (PDMS) surfaces using dielectric barrier discharge (DBD) plasma in two different assemblies, one using the primary plasma jet obtained from a conventional DBD and the other using a DBD plasma jet transfer. The evolution of water contact angle (WCA) in function of plasma processing time and in function of aging time as well as the changes in the surface roughness of PDMS samples for both plasma treatments have been studied. We also compared vibrational and rotational temperatures for both plasmas and for the first time the vibrational temperature (T_vib) for the transferred plasma jet has been shown to be higher as compared with the primary jet. The increment in the T_vib value seems to be the main reason for the improvements in adhesion properties and surface wettability for the transferred plasma jet. Possible explanations for the increase in the vibrational temperature are presented.

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

    Science.gov (United States)

    Múgica-Vidal, Rodolfo; Alba-Elías, Fernando; Sainz-García, Elisa; Pantoja-Ruiz, Mariola

    2015-08-01

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

  8. Imploding process and x-ray emission of shotgun z-pinch plasma

    Energy Technology Data Exchange (ETDEWEB)

    Muto, Ryusuke [Nihon University, College of Science and Technology, Tokyo (Japan); Takasugi, Keiichi; Miyamoto, Tetsu [Nihon University, Atomic Energy Research Institute, Tokyo (Japan)

    2001-09-01

    Rayleigh-Taylor instability was observed on the surface of a contracting z-pinch plasma. Wavelength of the instability was analyzed from the envelope of the profile, and it increased with implosion. Analysis with finite Larmor radius effect shows that there is some acceleration of ions during the contraction process. A suggestion to obtain macroscopically uniform plasma is to increase plasma current without heating the plasma. (author)

  9. Numerical simulation of chemical processes in helium plasmas in atmosphere environment

    Institute of Scientific and Technical Information of China (English)

    欧阳建明; 郭伟; 王龙; 邵福球

    2005-01-01

    A model is built to study chemical processes in plasmas generated in helium with trace amounts of air at atmospheric pressure or low pressures. The plasma lifetimes and the temporal evolutions of the main charged species are presented. The plasma lifetimes are longer than that in air plasma at atmospheric pressure, but this is not true at low pressures. The electron number density does not strictly obey the exponential damping law in a longer period.

  10. Hybrid layers deposited by an atmospheric pressure plasma process for corrosion protection of galvanized steel.

    Science.gov (United States)

    Del Frari, D; Bour, J; Bardon, J; Buchheit, O; Arnoult, C; Ruch, D

    2010-04-01

    Finding alternative treatments to reproduce anticorrosion properties of chromated coatings is challenging since both physical barrier and self-healing effects are needed. Siloxane based treatments are known to be a promising way to achieve physical barrier coatings, mainly plasma polymerized hexamethyldisiloxane (ppHMDSO). In addition, it is known that cerium-based coatings can also provide corrosion protection of metals by means of self-healing effect. In this frame, innovative nanoAlCeO3/ppHMDSO layers have thus been deposited and studied. These combinations allow to afford a good physical barrier effect and active properties. Liquid siloxane and cerium-based particles mixture is atomized and introduced as precursors into a carrier gas. Gas mixture is then injected into an atmospheric pressure dielectric barrier discharge (DBD) where plasma polymerization of the siloxane precursor occurs. The influence of cerium concentration on the coating properties is investigated: coating structure and topography have been studied by scanning electron microscopy (SEM) and interferometry, and corrosion resistance of these different coatings is compared by electrochemistry techniques: polarization curves and electrochemical impedance spectroscopy (EIS). Potential self-healing property afforded by cerium in the layer was studied by associating EIS measurements and nanoscratch controlled damaging. Among the different combinations investigated, mixing of plasma polymerized HMDSO and AICeO3 nanoparticles seems to give promising results with a good physical barrier and interesting electroactive properties. Indeed, corrosion currents measured on such coatings are almost as low as those measured with the chromated film. Combination of nanoscratch damaging of layers with EIS experiments to investigate self-healing also allow to measure the active protection property of such layers.

  11. Plasma diagnostics in a pulsed accelerator used for material processing

    Energy Technology Data Exchange (ETDEWEB)

    Zhukeshov, A [Science Research Institute of Experimental and Theoretical Physics, al-Farabi Kazakh National University, 96a Tole bi str., 050012 Almaty (Kazakhstan)

    2007-04-15

    Results of research work of a pulsed plasma accelerator, designed as diagnostic and material science stands in SRIETP are presented. We present results on the development of electric and magnetic probes used for measurement of plasma parameters. The physical properties and changes in structure of vanadium alloy, common quality carbon and stainless steels have been investigated as well.

  12. Titanium Metal Powder Production by the Plasma Quench Process

    Energy Technology Data Exchange (ETDEWEB)

    R. A. Cordes; A. Donaldson

    2000-09-01

    The goals of this project included the scale-up of the titanium hydride production process to a production rate of 50 kg/hr at a purity level of 99+%. This goal was to be achieved by incrementally increasing the production capability of a series of reactor systems. This methodic approach was designed to allow Idaho Titanium Technologies to systematically address the engineering issues associated with plasma system performance, and powder collection system design and performance. With quality powder available, actual fabrication with the titanium hydride was to be pursued. Finally, with a successful titanium production system in place, the production of titanium aluminide was to be pursued by the simultaneously injection of titanium and aluminum precursors into the reactor system. Some significant accomplishments of the project are: A unique and revolutionary torch/reactor capable of withstanding temperatures up to 5000 C with high thermal efficiency has been operated. The dissociation of titanium tetrachloride into titanium powder and HC1 has been demonstrated, and a one-megawatt reactor potentially capable of producing 100 pounds per hour has been built, but not yet operated at the powder level. The removal of residual subchlorides and adsorbed HC1 and the sintering of powder to form solid bodies have been demonstrated. The production system has been operated at production rates up to 40 pounds per hour. Subsequent to the end of the project, Idaho Titanium Technologies demonstrated that titanium hydride powder can indeed be sintered into solid titanium metal at 1500 C without sintering aids.

  13. The Main Plasma Chemical Process of Nitric Oxide Production by Arc Discharge%The Main Plasma Chemical Process of Nitric Oxide Production by Arc Discharge

    Institute of Scientific and Technical Information of China (English)

    杨旗; 胡辉; 陈卫鹏; 许杰; 张锦丽; 吴双

    2011-01-01

    By adopting the optical multi-channel analyzer combined with fourier transform infrared (FTIR) spectrometer, the dominant free radicals and products generated by arc discharge were measured and studied, and the main plasma chemical reaction process in the nitric oxide production by arc discharge was identified. Plasma chemical kinetic curves of O, O2, N2, N and NO were simulated by using CHEMKIN and MATLAB. The results show that the main plasma chemical reaction process of nitric oxide production by arc discharge is a replacement reaction between O and N2, where NO can be generated instantaneously when discharging reaches stable.

  14. A Study on Plasma-Initiated Polymerization of Long Alkyl Chain Methacrylates%甲基丙烯酸长链酯的等离子体引发聚合

    Institute of Scientific and Technical Information of China (English)

    张正彪; 路建美; 程振平; 朱秀林

    2001-01-01

    The polymerization of n-alkyl methacrylate(n=8,12,14) was carried out by means of plasma-initiation. Many factors affecting the polymer conversion and molecular weight have been studied systematically. The polymerization features of the three n-alkyl methacrylates were compared, and the configuration of polymer has been elucidated by NMR. The results indicate that plasma-initiated polymerization not only complies with free-radical mechanism but also has the character of living-polymerization.%研究了甲基丙烯酸正辛酯、甲基丙烯酸正十二酯、甲基丙烯酸正十四酯的等离子体引发本体聚合。考察了各种操作参数对聚合转化率、相对分子质量的影响。并将三种长链酯的聚合情况进行对比,结果表明,随着链长的增加,等离子体引发聚合的活性降低。利用核磁共振测定了聚合物的微观结构,结果与常规自由基加热聚合产物相同。表明等离子体引发聚合是按自由基聚合机理进行的,并具有活性聚合的特征。

  15. Analysis of Physics Processes in the AC Plasma Torch Discharge under High Pressure

    Science.gov (United States)

    Safronov, A. A.; Vasilieva, O. B.; Dudnik, J. D.; E Kuznetsov, V.; Kuchina, J. A.; Shiryaev, V. N.; Pavlov, A. V.

    2017-04-01

    The paper is devoted to investigation of electrophysical processes in the electric discharge generated by a three-phase AC plasma torch when using a high pressure inert working gas. AC plasma torch design with end electrodes intended for work on inert gases at pressures up to 81 bar is studied. Current-voltage characteristics for different gas flow rates and pressures are presented. Physical processes characteristics of the arising voltage ripples which depend on various working parameters of the plasma torch have been investigated. Arc burning processes in the electric discharge chamber of the three-phase AC plasma torch at various working parameters were photographed.

  16. The kinetic studies of direct methane oxidation to methanol in the plasma process

    Institute of Scientific and Technical Information of China (English)

    INDARTO Antonius; CHOI Jae-Wook; LEE Hwaung; SONG Hyung Keun

    2008-01-01

    The research outlined here includes a study of methanol production from direct methane conversion by means of thermal and plasma method. The kinetic study, derived from thermal-based approach, was carried out to investigate thoroughly the possible intermediate species likely to be presented in the process. A set of plasma experiments was undertaken by using dielectric barrier discharge (DBD), classified as non-thermal plasma, done at atmospheric pressure and room temperature. Plasma proc-ess yields more methanol than thermal process at the same methane conversion rates and methane to oxygen feed ratios. Oxidation reaction of thermal process resulted CO and CO2 as the most dominant products and the selectivity reached 19% and 68%, respectively. Moreover, more CO and less CO2 were produced in plasma process than in thermal process. The selectivity of CO and CO2 by plasma was 47% and 20%, respectively. Ethane (C2H6) was detected as the only higher hydrocarbon with a signifi-cant concentration. The concentration of ethane reached 9% of the total products in plasma process and 17% in thermal process. The maximum selectivity of methanol, the target material of this research, was 12% obtained by plasma method and less than 5% by thermal process. In some certain points, the kinetic model closely matched with the experimental results.

  17. Applications and challenges of plasma processes in nanobiotechnology

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, F; Colpo, P, E-mail: francois.rossi@jrc.ec.europa.eu [European Commission, Joint Research Centre, Institute for Health and Consumer Protection (IHCP), I-21020, Ispra (Italy)

    2011-05-04

    We present an overview of the possibilities offered by plasma technologies, in particular the combination plasma polymers deposition, colloidal lithography, e-beam lithography and microcontact printing, to produce micro- and nanostructured surfaces with chemical and topographical contrast for applications in nanobiotechnology. It is shown that chemical and topographical patterns can be obtained on different substrates, with dimensions down to a few tenths of 10 nm. The applications of these nanostructured surfaces in biology, biochemistry and biodetection are presented and the advantages and limitation of the plasma techniques in this context underlined.

  18. Surface modification of porous polypropylene membrane by plasma-initiated RAFT graft polymerization%等离子体引发的RAFT接枝聚合对聚丙烯多孔膜的表面改性

    Institute of Scientific and Technical Information of China (English)

    周月; 汪思孝; 黄健; 王晓琳

    2012-01-01

    采用可逆加成-断裂链转移(RAFT)可控/活性自由基聚合方法,以二硫代苯甲酸-2-腈基异丙酯(CPDB)为RAFT链转移剂并以丙烯酸(AA)为单体,在聚丙烯(PP)多孔膜表面进行了等离子体引发的RAFT接枝聚合改性.聚合动力学研究结果表明:聚合反应具有RAFT聚合动力学特征,等离子体处理可以引发RAFT自由基聚合.以傅立叶红外光谱仪(FT- IR)、扫描电子显微镜(SEM)、压汞、水通量等方法,研究了改性多孔膜的表面化学与形态结构及孔结构特征.改性多孔膜表面的接枝率随单体转化率的提高呈线性增长,表面亲水性得到显著改善,同时膜孔径及水通量随接枝聚合时间的提高持续减小.其趋势符合RAFT可控/活性自由基聚合机制,实现了多孔膜膜孔径控制的目的.%A reversible addition-fragment chain transfer (RAFT) graft polymerization method, initiated by the pulsed plasma, was used to modify the surface of porous polypropylene ( PP) membrane, with 2-cyanoprop-2-yl dithiobenzoate (CPDB) used as the RAFT agent and acrylic acid as the monomer. The result of the graft polymerization kinetics was in agreement with that of the RAFT polymerization, and the plasma-initiated method was feasible. The surface chemistry, the surface morphology and the porous structure of modified PP membranes were evaluated by Fourier transform minfrared spectroscopy ( FT-IR) , scanning electron microscope (SEM) ,mercury intrusion, and water flux measurements. Graft amounts of modified membranes exhibited a linear increase with the increase of the conversion, while pore sizes and water fluxes were decreased continuously with the prolonging of polymerization time. The pore size of the porous PP membrane was regulated by a simple tune of the polymerization time or the monomer conversion by the RAFT graft polymerization.

  19. Plasma-Based Surface Modification of Polydimethylsiloxane for PDMS-PDMS Molding

    OpenAIRE

    Lopera, S.; Mansano, R. D.

    2012-01-01

    We present and compare two processes for plasma-based surface modification of Polydimethylsiloxane (PDMS) to achieve the antisticking behavior needed for PDMS-PDMS molding. The studied processes were oxygen plasma activation for vapor phase silanization and plasma polymerization with tetrafluoromethane/hydrogen mixtures under different processing conditions. We analyzed topography changes of the treated surfaces by atomic force microscopy and contact angle measurements. Plasma treatment were ...

  20. Impacts of Ambient and Ablation Plasmas on Short- and Ultrashort-Pulse Laser Processing of Surfaces

    Directory of Open Access Journals (Sweden)

    Nadezhda M. Bulgakova

    2014-12-01

    Full Text Available In spite of the fact that more than five decades have passed since the invention of laser, some topics of laser-matter interaction still remain incompletely studied. One of such topics is plasma impact on the overall phenomenon of the interaction and its particular features, including influence of the laser-excited plasma re-radiation, back flux of energetic plasma species, and massive material redeposition, on the surface quality and processing efficiency. In this paper, we analyze different plasma aspects, which go beyond a simple consideration of the well-known effect of plasma shielding of laser radiation. The following effects are considered: ambient gas ionization above the target on material processing with formation of a “plasma pipe”; back heating of the target by both laser-driven ambient and ablation plasmas through conductive and radiative heat transfer; plasma chemical effects on surface processing including microstructure growth on liquid metals; complicated dynamics of the ablation plasma flow interacting with an ambient gas that can result in substantial redeposition of material around the ablation spot. Together with a review summarizing our main to-date achievements and outlining research directions, we present new results underlining importance of laser plasma dynamics and photoionization of the gas environment upon laser processing of materials.

  1. 聚酰胺6聚合反应工艺的探讨--浅析国内外聚合管生产技术%EXPLORATION ON THE POLYMERIZATION PROCESS OF POLYAMIDE 6 --ELEMENTARY ANALYSIS OF POLYMERIZATION TUBE TECHNOLOGY AT HOME AND ABROAD

    Institute of Scientific and Technical Information of China (English)

    吴雷; 姚阳照

    2000-01-01

    论述了聚酰胺6聚合反应的原理,介绍了德国Zirrmer、瑞士EMS-Inventa、德国Karl.Fisher三家公司的聚合反应工艺和设备的特点。%The Polymerization principle of polyamide 6 is discussed. The polymerization process and equipment feaatue of Zimeer, EMS- In-venta and Karl. Fisher companies are introduced.

  2. Simultaneous Au(III) Extraction and In Situ Formation of Polymeric Membrane-Supported Au Nanoparticles: A Sustainable Process with Application in Catalysis.

    Science.gov (United States)

    Mora-Tamez, Lucía; Esquivel-Peña, Vicente; Ocampo, Ana L; Rodríguez de San Miguel, Eduardo; Grande, Daniel; de Gyves, Josefina

    2017-04-10

    A polymeric membrane-supported catalyst with immobilized gold nanoparticles (AuNPs) was prepared through the extraction and in situ reduction of Au(III) salts in a one-step strategy. Polymeric inclusion membranes (PIMs) and polymeric nanoporous membranes (PNMs) were tested as different membrane-support systems. Transport experiments indicated that PIMs composed of cellulose triacetate, 2-nitrophenyloctyl ether, and an aliphatic tertiary amine (Adogen 364 or Alamine 336) were the most efficient supports for Au(III) extraction. The simultaneous extraction and reduction processes were proven to be the result of a synergic phenomenon in which all the membrane components were involved. Scanning electron microscopy characterization of cross-sectional samples suggested a distribution of AuNPs throughout the membrane. Transmission electron microscopy characterization of the AuNPs indicated average particle sizes of 36.7 and 2.9 nm for the PIMs and PNMs, respectively. AuNPs supported on PIMs allowed for >95.4 % reduction of a 0.05 mmol L(-1) 4-nitrophenol aqueous solution with 10 mmol L(-1) NaBH4 solution within 25 min. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. EFFECTS OF REACTION AND PROCESSING PARAMETERS ON ETHYLENE POLYMERIZATION USING DIFFERENT ZIEGLER-NATTA CATALYSTS:EMPLOYMENT OF TAGUCHI EXPERIMENTAL DESIGN AND RESPONSE SURFACE METHOD

    Institute of Scientific and Technical Information of China (English)

    Mohammad Najafi; Vahid Haddadi-Asl

    2007-01-01

    Different Ziegler-Natta catalysts were employed to polymerize ethylene.To investigate the influences of reaction parameters,namely Al/Ti molar ratio,hydrogen and processing parameters,I.e.ethylene pressure and temperature,a Taguchi experimental design was worked out.An L27 orthogonal array was chosen to take the above-mentioned parameters and relevant interactions into account.Response surface method was the tool used to analyze the experimental design results.Al/Ti,ethylene pressure and temperature were selected as experimental design factors.and catalyst activity and polymerization yield were the response parameters.Increasing pressure,due to an increment in monomer accessibility,and rising Al/Ti,because of higher reduction in the catalysts,cause an increase in both polymerization yield and catalyst activity.Nonetheless,a higher temperature,thanks to reducing ethylene solubility in the slurry medium and partially catalyst destruction.lead to a reduction in both response parameters.A synergistic eflfect was also observed between temperature and pressure.All catalyst activities will reduce in the presence of hydrogen.Molecular weight also shows a decline in the presence of hydrogen as a transfer agent.However,the polydispersity index remains approximately intact.Using SEM,various morphologies,owing to different catalyst morphologies,were seen for the polyethylene.

  4. Hybrid processing of Ti-6Al-4V using plasma immersion ion implantation combined with plasma nitriding

    Directory of Open Access Journals (Sweden)

    Silva Maria Margareth da

    2006-01-01

    Full Text Available Based on the fact that the Ti-6Al-4V alloy has good mechanical properties, excellent resistance to corrosion and also excellent biocompatibility, however with low wear resistance, this work aims to test plasma processes or combination of plasma and ion implantation processes to improve these characteristics. Two types of processing were used: two steps PIII (Plasma Immersion Ion Implantation combined with PN (Plasma Nitriding and single step PIII treatment. According to Auger Electron Spectroscopy (AES results, the best solution was obtained by PIII for 150 minutes resulting in ~ 65 nm of nitrogen implanted layer, while the sample treated with PIII (75 minutes and PN (75 minutes reached ~ 35 nm implanted layer. The improvement of surface properties could also be confirmed by the nanoindentation technique, with values of hardness increasing for both processes. AFM (Atomic Force Microscopy characterization showed that the single step PIII process presented greater efficiency than the duplex process (PIII + PN, probably due to the sputtering occurring during the second step (PN removing partially the implanted layer of first step (PIII.

  5. Atmospheric-Pressure Plasma Interaction with Soft Materials as Fundamental Processes in Plasma Medicine.

    Science.gov (United States)

    Takenaka, Kosuke; Miyazaki, Atsushi; Uchida, Giichiro; Setsuhara, Yuichi

    2015-03-01

    Molecular-structure variation of organic materials irradiated with atmospheric pressure He plasma jet have been investigated. Optical emission spectrum in the atmospheric-pressure He plasma jet has been measured. The spectrum shows considerable emissions of He lines, and the emission of O and N radicals attributed to air. Variation in molecular structure of Polyethylene terephthalate (PET) film surface irradiated with the atmospheric-pressure He plasma jet has been observed via X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). These results via XPS and FT-IR indicate that the PET surface irradiated with the atmospheric-pressure He plasma jet was oxidized by chemical and/or physical effect due to irradiation of active species.

  6. Reliability of plasma-sprayed coatings: monitoring the plasma spray process and improving the quality of coatings

    Science.gov (United States)

    Fauchais, P.; Vardelle, M.; Vardelle, A.

    2013-06-01

    As for every coating technology, the reliability and reproducibility of coatings are essential for the development of the plasma spraying technology in industrial manufacturing. They mainly depend on the process reliability, equipment and spray booth maintenance, operator training and certification, implementation and use of consistent production practices and standardization of coating testing. This paper deals with the first issue, that is the monitoring and control of the plasma spray process; it does not tackle the coating characterization and testing methods. It begins with a short history of coating quality improvement under plasma spray conditions over the last few decades, details the plasma spray torches used in the industry, the development of the measurements of in-flight and impacting particle parameters and then of sensors. It concludes with the process maps that describe the interrelations between the operating parameters of the spray process, in-flight particle characteristics and coating properties and with the potential of in situ monitoring of the process by artificial neural networks and fuzzy logic methods.

  7. Plasma processes and applications in NanoBiotechnology

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, F; Colpo, P, E-mail: francois.rossi@jrc.ec.europa.eu [European Commission, Joint Research Centre, Institute for Health and Consumer Protection (IHCP), I-21020, Ispra (Italy)

    2010-11-01

    Nanostructured surfaces presenting chemical or topographical patterns are now being increasingly developed in nanobiotechnology. Major applications are related to cell culture models and biodetection. We show that plasma technologies, in particular the combination plasma polymers deposition and etching, together with colloidal lithography, e-beam lithography and microcontact printing, are essential tools to produce nanostructured surfaces. We show that chemical and topographical patterns can be obtained on different substrates, with dimensions down to some 10 nm. The applications of these nanostructured surfaces in biology and bio-detection are reviewed and the advantages and limitation of the techniques underlined.

  8. Plasma Surface Treatment of Powder Materials — Process and Application

    Directory of Open Access Journals (Sweden)

    Monika Pavlatová

    2012-01-01

    Full Text Available Polyolefin particles are hydrophobic, and this prevents their use for various applications. Plasma treatment is an environment-friendly polyolefin hydrophilisation method. We developed an industrial-scale plant for plasma treatment of particles as small as micrometers in diameter. Materials such as PE waxes, UHMWPE and powders for rotomolding production were tested to verify their new surface properties. We achieved significantly increased wettability of the particles, so that they are very easily dispersive in water without agglomeration, and their higher surface energy is retained even after sintering in the case of rotomolding powders.

  9. Research on the Plasma Spray Process Applying the Finite Element Method

    Directory of Open Access Journals (Sweden)

    Raimonda Lukauskaitė

    2015-03-01

    Full Text Available The article investigates the physical processes of plasma spraying. The application of the finite element method has assisted in establishing the distribution of the voltage of the plasma arc and current density in the plasma stream during numerical simulation. With reference to the results of experimental data, the real location of an anode spot of the electric arc in the plasma spray process has been evaluated. The paper has calculated the values of electromagnetic Lorentz forces and established their influence on plasma flow. With the help of the two-layer model for the semi-molten nickel particle, contact between the particle and substrate during plasma spraying has been simulated.

  10. Influence of radiative processes on the ignition of deuterium–tritium plasma containing inactive impurities

    Energy Technology Data Exchange (ETDEWEB)

    Gus’kov, S. Yu., E-mail: guskov@sci.lebedev.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); Sherman, V. E. [Peter the Great St. Petersburg Polytechnic University (Russian Federation)

    2016-08-15

    The degree of influence of radiative processes on the ignition of deuterium–tritium (DT) plasma has been theoretically studied as dependent on the content of inactive impurities in plasma. The analytic criterion of plasma ignition in inertial confinement fusion (ICF) targets is modified taking into account the absorption of intrinsic radiation from plasma in the ignition region. The influence of radiative processes on the DT plasma ignition has been analytically and numerically studied for plasma that contains a significant fraction of inactive impurities either as a result of DT fuel mixing with ICF target ablator material or as a result of using light metal DT-hydrides as solid noncryogenic fuel. It has been shown that the effect of the absorption of intrinsic radiation leads to lower impurity-induced increase in the ignition energy as compared to that calculated in the approximation of optically transparent ignition region.

  11. Influence of radiative processes on the ignition of deuterium-tritium plasma containing inactive impurities

    Science.gov (United States)

    Gus'kov, S. Yu.; Sherman, V. E.

    2016-08-01

    The degree of influence of radiative processes on the ignition of deuterium-tritium (DT) plasma has been theoretically studied as dependent on the content of inactive impurities in plasma. The analytic criterion of plasma ignition in inertial confinement fusion (ICF) targets is modified taking into account the absorption of intrinsic radiation from plasma in the ignition region. The influence of radiative processes on the DT plasma ignition has been analytically and numerically studied for plasma that contains a significant fraction of inactive impurities either as a result of DT fuel mixing with ICF target ablator material or as a result of using light metal DT-hydrides as solid noncryogenic fuel. It has been shown that the effect of the absorption of intrinsic radiation leads to lower impurity-induced increase in the ignition energy as compared to that calculated in the approximation of optically transparent ignition region.

  12. Application of Atmospheric-Pressure Microwave Line Plasma for Low Temperature Process

    Science.gov (United States)

    Suzuki, Haruka; Nakano, Suguru; Itoh, Hitoshi; Sekine, Makoto; Hori, Masaru; Toyoda, Hirotaka

    2015-09-01

    Atmospheric pressure (AP) plasmas have been given much attention because of its high cost benefit and a variety of possibilities for industrial applications. In various kinds of plasma production technique, pulsed-microwave discharge plasma using slot antenna is attractive due to its ability of high-density and stable plasma production. In this plasma source, however, size of the plasma has been limited up to a few cm in length due to standing wave inside a waveguide. To solve this, we have proposed a newly-developed AP microwave plasma source that utilizes not standing wave but travelling wave. By using this plasma source, spatially-uniform AP line plasma with 40 cm in length was realized by pure helium discharge in 60 cm slot and with nitrogen gas additive of 1%. Furthermore, gas temperature as low as 400 K was realized in this device. In this study, as an example of low temperature processes, hydrophilic treatment of PET films was performed. Processing speed increased with pulse frequency and a water contact angle of ~20° was easily obtained within 5 s with no thermal damage to the substrate. To evaluate treatment-uniformity of long line length, PET films were treated by 90 cm slot-antenna plasma and uniform treatment performance was confirmed.

  13. Comparison endpoint study of process plasma and secondary electron beam exciter optical emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Stephan Thamban, P. L.; Yun, Stuart; Padron-Wells, Gabriel; Hosch, Jimmy W.; Goeckner, Matthew J. [Department of Mechanical Engineering, University of Texas at Dallas, 800W Campbell Road, Richardson, Texas 75080 (United States); Department of Electrical Engineering, University of Texas at Dallas, 800W Campbell Road, Richardson, Texas 75080 (United States); Verity Instruments, Inc., 2901 Eisenhower Street, Carrollton, Texas 75007 (United States); Department of Mathematical Sciences, University of Texas at Dallas, 800 W Campbell Road, Richardson, Texas 75080 (United States)

    2012-11-15

    Traditionally process plasmas are often studied and monitored by optical emission spectroscopy. Here, the authors compare experimental measurements from a secondary electron beam excitation and direct process plasma excitation to discuss and illustrate its distinctiveness in the study of process plasmas. They present results that show excitations of etch process effluents in a SF{sub 6} discharge and endpoint detection capabilities in dark plasma process conditions. In SF{sub 6} discharges, a band around 300 nm, not visible in process emission, is observed and it can serve as a good indicator of etch product emission during polysilicon etches. Based on prior work reported in literature the authors believe this band is due to SiF{sub 4} gas phase species.

  14. Elementary Processes and Kinetic Modeling for Hydrogen and Helium Plasmas

    Directory of Open Access Journals (Sweden)

    Roberto Celiberto

    2017-05-01

    Full Text Available We report cross-sections and rate coefficients for excited states colliding with electrons, heavy particles and walls useful for the description of H 2 /He plasma kinetics under different conditions. In particular, the role of the rotational states in resonant vibrational excitations of the H 2 molecule by electron impact and the calculation of the related cross-sections are illustrated. The theoretical determination of the cross-section for the rovibrational energy exchange and dissociation of H 2 molecule, induced by He atom impact, by using the quasi-classical trajectory method is discussed. Recombination probabilities of H atoms on tungsten and graphite, relevant for the determination of the nascent vibrational distribution, are also presented. An example of a state-to-state plasma kinetic model for the description of shock waves operating in H 2 and He-H 2 mixtures is presented, emphasizing also the role of electronically-excited states in affecting the electron energy distribution function of free electrons. Finally, the thermodynamic properties and the electrical conductivity of non-ideal, high-density hydrogen plasma are finally discussed, in particular focusing on the pressure ionization phenomenon in high-pressure high-temperature plasmas.

  15. Plasma processing of fibre materials for enhanced impact protection

    NARCIS (Netherlands)

    Creyghton, Y.L.M.; Simor, M.

    2009-01-01

    The performance of lightweight impact protective clothing depends on the constituting materials, their assembly in a system and interaction under various dynamic impact conditions. In this paper an overview of options for improved impact protective clothing systems based on a new plasma technology i

  16. Plasma processing of fibre materials for enhanced impact protection

    NARCIS (Netherlands)

    Creyghton, Y.L.M.; Simor, M.

    2009-01-01

    The performance of lightweight impact protective clothing depends on the constituting materials, their assembly in a system and interaction under various dynamic impact conditions. In this paper an overview of options for improved impact protective clothing systems based on a new plasma technology i

  17. Thomson Scattering Process in Laser-Produced Plasmas

    Institute of Scientific and Technical Information of China (English)

    YU Quan-Zhi; JIANG Xiao-Hua; LI Wen-Hong; LIU Shen-Ye; ZHENG Zhi-Jian; ZHANG Jie; LI Yu-Tong; ZHENG Jun; YAN Fei; LU Xin; WANG Zhe-Bin; ZHENG Jian; YU Chang-Xuan

    2005-01-01

    @@ We present the evolutions of the electron temperature and plasma expansion velocity with Thomson scattering experiment. The observed time-resolved ion-acoustic image is reproduced by a numerical code which couples the Thomson scattering theory with the output parameters of the one-dimensional hydrocode MEDUSA.

  18. Plasma processing of fibre materials for enhanced impact protection

    NARCIS (Netherlands)

    Creyghton, Y.L.M.; Simor, M.

    2009-01-01

    The performance of lightweight impact protective clothing depends on the constituting materials, their assembly in a system and interaction under various dynamic impact conditions. In this paper an overview of options for improved impact protective clothing systems based on a new plasma technology

  19. Synthesis and characterization of Ce_(0.8)Sm_(0.2)O_(1.9) nanopowders using an acrylamide polymerization process

    Institute of Scientific and Technical Information of China (English)

    郑颖平; 王绍荣; 王振荣; 邬理伟; 孙岳明

    2010-01-01

    Ce0.8Sm0.2O1.9(SDC) nanopowders were synthesized by an acrylamide polymerization process.The XRD results showed that SDC powders prepared at 700 °C possessed a cubic fluorite structure.Transmission electron microscopy(TEM) indicated that the particle sizes of powders were in the range of 10-15 nm.A 98.3% of theoretical density was obtained when the SDC pellets were sintered at 1350 °C for 5 h,indicating that the powders had good sinterability.The conductivity of the sintered SDC ceramics was 0.019 S/cm at 6...

  20. Effects of extra-cellular polymeric substances on organic pollutants biodegradation kinetics for A-step of adsorption-biodegradation process

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The features of organic pollutants degradation mainly characterized by bio-flocculation for step-A of adsorption-biodegredation(AB) process were studied. By investigating the relationship of extracellular polymeric substances(EPS) with bioflocculation and introducing kinetic model of organic pollutant degradation into EPS, the kinetic model of organic pollutant degradation for step-A bioflocculation was deducted. And through the experiments,the kinetic constants were calculated as follows: k1 =0. 005 3; kc1 =1710.7 and vmax1=10 min-1.

  1. Electroacoustic Process Study of Plasma Sparker Under Different Water Depth

    KAUST Repository

    Huang, Yifan

    2015-01-05

    The plasma sparker has been applied in oceanic high-resolution seismic exploration for decades. Normally it is towed on the water surface. This is suitable for shallow water, but if the water depth is great, the resolution will decrease dramatically, especially in the horizontal direction. This paper proposes the concept of a deep-towed plasma sparker and presents an experimental study of plasma sparker performance in terms of electric parameters, bubble behavior, and acoustic characteristics. The results show that hydrostatic pressure at a source depth ranging from 1 to 2000 m has a negligible influence on the electric parameters but a strong influence on bubble behavior, wherein both the maximum bubble radius and oscillation period are decreased. The collapse pulse vanishes when the source depth reaches 1000 m or deeper, and no bubble oscillation can be distinguished. The source level (evaluated by the expansion pulse) is also decreased as the source depth increases; moreover, the greater the discharge energy, the smaller the source level loss. The discharge energy per electrode should be greater than 20 J for the deep-towed plasma sparker, which can make the source level loss induced by hydrostatic pressure smaller than the transmission loss. The fast Fourier transform (FFT) results show that the dominant energy is around 20 kHz, which is mainly induced by the expansion pulse and its oscillation. According to the simulation results, the fundamental frequency of the acoustic waveform increases with source depth in accord with a log linear trend, and also reaches tens of kilohertz in deep water. So, before the development of deep-towed plasma sparker, a new technical solution will need to be developed to solve this problem. © 1976-2012 IEEE.

  2. Nonlinear plasma processes and the formation of electron kappa distribution

    Science.gov (United States)

    Yoon, Peter

    2016-07-01

    The goal of nonequilibrium statistical mechanics is to establish fundamental relationship between the time irreversible macroscopic dynamics and the underlying time reversible behavior of microscopic system. The paradigm of achieving this seemingly paradoxical goal is through the concept of probability. For classical systems Boltzmann accomplished this through his H theorem and his kinetic equation for dilute gas. Boltzmann's H function is the same as classical extensive entropy aside from the minus sign, and his kinetic equation is applicable for short-range molecular interaction. For plasmas, the long-range electromagnetic force dictates the inter-particular interaction, and the underlying entropy is expected to exhibit non-extensive, or non-additive behavior. Among potential models for the non-additive entropy, the celebrated Tsallis entropy is the most well known. One of the most useful fundamental kinetic equations that governs the long-range plasma interaction is that of weak turbulence kinetic theory. At present, however, there is no clear-cut connection between the Tsallis entropy and the kinetic equations that govern plasma behavior. This can be contrasted to Boltzmann's H theorem, which is built upon his kinetic equation. The best one can do is to show that the consequences of Tsallis entropy and plasma kinetic equation are the same, that is, they both imply kappa distribution. This presentation will overview the physics of electron acceleration by beam-generated Langmuir turbulence, and discuss the asymptotic solution that rigorously can be shown to correspond to the kappa distribution. Such a finding is a strong evidence, if not water-tight proof, that there must be profound inter-relatioship between the Tsallis thermostatistical theory and the plasma kinetic theory.

  3. Achieving atomistic control in materials processing by plasma-surface interactions

    Science.gov (United States)

    Chang, Jeffrey; Chang, Jane P.

    2017-06-01

    The continuous down-scaling of electronic devices and the introduction of functionally improved novel materials require a greater atomic level controllability in the synthesis and patterning of thin film materials, especially with regards to deposition uniformity and conformality as well as etching selectivity and anisotropy. The richness of plasma chemistry and the corresponding plasma-surface interactions provide the much needed processing flexibility and efficacy. To achieve the integration of the novel materials into devices, plasma-enhanced atomic layer processing techniques are emerging as the enabling factors to obtain atomic scale control of complex materials and nanostructures. This review focuses on an overview of the role of respective plasma species involved in plasma-surface interactions, addressing their respective and synergistic effects, which is followed by two distinct applications: plasma-enhanced atomic layer deposition (ALD) and atomic layer etching (ALE). For plasma-enhanced ALD, this review emphasizes the use of plasma chemistry to enable alternative pathways to synthesize complex materials at low temperatures and the challenges associated with deposition conformality. For plasma enabled ALE processes, the review focuses on the surface-specific chemical reactions needed to achieve desirable selectivity and anisotropy.

  4. Tech-X Corporation releases simulation code for solving complex problems in plasma physics : VORPAL code provides a robust environment for simulating plasma processes in high-energy physics, IC fabrications and material processing applications

    CERN Multimedia

    2005-01-01

    Tech-X Corporation releases simulation code for solving complex problems in plasma physics : VORPAL code provides a robust environment for simulating plasma processes in high-energy physics, IC fabrications and material processing applications

  5. VUV diagnostic of electron impact processes in low temperature molecular hydrogen plasma

    CERN Document Server

    Komppula, J

    2015-01-01

    Novel methods for diagnostics of molecular hydrogen plasma processes, such as ionization, production of high vibrational levels, dissociation of molecules via excitation to singlet and triplet states and production of metastable states, are presented for molecular hydrogen plasmas in corona equilibrium. The methods are based on comparison of rate coefficients of plasma processes and optical emission spectroscopy of lowest singlet and triplet transitions, i.e. Lyman-band ($B^1\\Sigma^+_u \\rightarrow X^1\\Sigma^+_g$) and molecular continuum ($a^3\\Sigma^+_g \\rightarrow b^3\\Sigma^+_u$), of the hydrogen molecule in VUV wavelength range. Comparison of rate coefficients of spin-allowed and/or spin-forbidden excitations reduces the uncertainty caused by the non-equilibrium distributions of electron energy and molecular vibrational level, which are typically known poorly in plasma sources. The described methods are applied to estimate the rates of various plasma processes in a filament arc discharge.

  6. Biokompatible Polymere

    Science.gov (United States)

    Ha, Suk-Woo; Wintermantel, Erich; Maier, Gerhard

    Der klinische Einsatz von synthetischen Polymeren begann in den 60-er Jahren in Form von Einwegartikeln, wie beispielsweise Spritzen und Kathetern, vor allem aufgrund der Tatsache, dass Infektionen infolge nicht ausreichender Sterilität der wiederverwendbaren Artikel aus Glas und metallischen Werkstoffen durch den Einsatz von sterilen Einwegartikeln signifikant reduziert werden konnten [1]. Die Einführung der medizinischen Einwegartikel aus Polymeren erfolgte somit nicht nur aus ökonomischen, sondern auch aus hygienischen Gründen. Wegen der steigenden Anzahl synthetischer Polymere und dem zunehmenden Bedarf an ärztlicher Versorgung reicht die Anwendung von Polymeren in der Medizin von preisgünstigen Einwegartikeln, die nur kurzzeitig intrakorporal eingesetzt werden, bis hin zu Implantaten, welche über eine längere Zeit grossen Beanspruchungen im menschlichen Körper ausgesetzt sind. Die steigende Verbreitung von klinisch eingesetzten Polymeren ist auf ihre einfache und preisgünstige Verarbeitbarkeit in eine Vielzahl von Formen und Geometrien sowie auf ihr breites Eigenschaftsspektrum zurückzuführen. Polymere werden daher in fast allen medizinischen Bereichen eingesetzt.

  7. Laser plasma simulations of the generation processes of Alfven and collisionless shock waves in space plasma

    Science.gov (United States)

    Prokopov, P. A.; Zakharov, Yu P.; Tishchenko, V. N.; Shaikhislamov, I. F.; Boyarintsev, E. L.; Melekhov, A. V.; Ponomarenko, A. G.; Posukh, V. G.; Terekhin, V. A.

    2016-11-01

    Generation of Alfven waves propagating along external magnetic field B0 and Collisionless Shock Waves propagating across B0 are studied in experiments with laser- produced plasma and magnetized background plasma. The collisionless interaction of interpenetrating plasma flows takes place through a so-called Magnetic Laminar Mechanism (MLM) or Larmor Coupling. At the edge of diamagnetic cavity LP-ions produce induction electric field Eφ which accelerates BP-ions while LP-ions rotate in opposite direction. The ions movement generates sheared azimuthal magnetic field Bφ which could launches torsional Alfven wave. In previous experiments at KI-1 large scale facility a generation of strong perturbations propagating across B0 with magnetosonic speed has been studied at a moderate value of interaction parameter δ∼0.3. In the present work we report on experiments at conditions of 5∼R2 and large Alfven-Mach number MA∼10 in which strong transverse perturbations traveling at a scale of ∼1 m in background plasma at a density of ∼3*1013 cm-3 is observed. At the same conditions but smaller MA ∼ 2 a generation, the structure and dynamic of Alfven wave with wavelength ∼0.5 m propagating along fields B0∼100÷500 G for a distance of ∼2.5 m is studied.

  8. Research of Hollow Cathode Remote Plasma Polymerization on Surface of Secondary Battery Separator%电池隔膜表面空心阴极等离子体接枝聚合研究

    Institute of Scientific and Technical Information of China (English)

    温贻芳; 陈新; 芮延年; 王红卫

    2012-01-01

    The surface of non-woven polypropylene secondary battery separator was modified by hollow cathode remote plasma polymerizatioa The polymerization mechanism was analyzed, and the effects of working parameters (such as discharge power, working gas flow rate, sample position etc. ) on the polymerization rate were studied systematically. The IR and SEM were used to analyze the chemical composition and the surface morphology. The results show that the hydrophilic group was imported on the surface of polypropylene after hollow cathode remote plasma modification, so that the wettability of the non-woven polypropylene secondary battery separator was greatly improved.%应用自制的空心阴极等离子体装置,引发丙烯酸在丙纶表面的接枝聚合,研究了等离子体接枝聚合作用机理,分析了等离子体接枝聚合各参数(放电功率、气体流量、丙烯酸蒸气流量、样品位置等)对聚合速率的影响.通过红外光谱、扫描电镜等对丙纶接枝聚合膜表面的化学组成和形态结构等进行了表征分析,证明了亲水基团的引入,改善了丙纶隔膜的亲水性能.

  9. Numerical simulation of the coal combustion process initiated by a plasma source

    Science.gov (United States)

    Askarova, A. S.; Messerle, V. E.; Ustimenko, A. B.; Bolegenova, S. A.; Maksimov, V. Yu.

    2014-12-01

    Numerical experiments on the torch combustion of the coal dust prepared by a plasma-thermochemical treatment for combustion have been done using the method of three-dimensional simulation. It is shown that the plasma preparation of coal for combustion enables one to optimize the process, improve the conditions for inflammation and combustion and minimize the emissions of harmful substances.

  10. Data processing of absorption spectra from photoionized plasma experiments at Z

    Energy Technology Data Exchange (ETDEWEB)

    Hall, I. M.; Durmaz, T.; Mancini, R. C. [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States); Bailey, J. E.; Rochau, G. A. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1196 (United States)

    2010-10-15

    We discuss the processing of x-ray absorption spectra from photoionized plasma experiments at Z. The data was recorded with an imaging spectrometer equipped with two elliptically bent potassium acid phthalate (KAP) crystals. Both time-integrated and time-resolved data were recorded. In both cases, the goal is to obtain the transmission spectra for quantitative analysis of plasma conditions.

  11. From interfacial ring-opening polymerization to melt processing of cellulose nanowhisker-filled polylactide-based nanocomposites.

    Science.gov (United States)

    Goffin, Anne-Lise; Raquez, Jean-Marie; Duquesne, Emmanuel; Siqueira, Gilberto; Habibi, Youssef; Dufresne, Alain; Dubois, Philippe

    2011-07-11

    In the present work, cellulose nanowhiskers (CNWs), extracted from ramie fibers, were incorporated in polylactide (PLA)-based composites. Prior to the blending, PLA chains were chemically grafted on the surface of CNW to enhance the compatibilization between CNW and the hydrophobic polyester matrix. Ring-opening polymerization of l-lactide was initiated from the hydroxyl groups available at the CNW surface to yield CNW-g-PLA nanohybrids. PLA-based nanocomposites were prepared by melt blending to ensure a green concept of the study thereby limiting the use of organic solvents. The influence of PLA-grafted cellulose nanoparticles on the mechanical and thermal properties of the ensuing nanocomposites was deeply investigated. The thermal behavior and mechanical properties of the nanocomposites were determined using differential scanning calorimetry (DSC) and dynamical mechanical and thermal analysis (DMTA), respectively. It was clearly evidenced that the chemical grafting of CNW enhances their compatibility with the polymeric matrix and thus improves the final properties of the nanocomposites. Large modification of the crystalline properties such as the crystallization half-time was evidenced according to the nature of the PLA matrix and the content of nanofillers.

  12. Educational software for the visualization of space plasma processes

    Science.gov (United States)

    Russell, C. T.; Le, G.; Luhmann, J. G.; Littlefield, B.

    1995-01-01

    The UCLA Space Physics Group has developed educational software composed of a series of modules to assist students with understanding basic concepts of space plasmas and charged particle motion. Present modules cover planetary magnetospheres, charged particle motion, cold plasma waves, collisionless shock waves, and solar wind. The software is designed around the principle that students can learn more by doing rather than by reading or listening. The programs provide a laboratory-like environment in which the student can control, observe, and measure complex behavior. The interactive graphics environment allows the student to visualize the results of his or her experimentation and to try different parameters as desired. The current version of the software runs on UNIX-based operating systems in an X-Windows environment. It has been used in a classroom setting at both UCLA and the University of California at San Diego.

  13. Dynamics of electronegative plasmas for materials processing. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lichtenberg, A.J.; Lieberman, M.A.

    1996-12-31

    Purpose was to study equilibrium particle and energy balance and heating mechanisms in electronegative rf discharges. Attention is given to formation of non-Maxwellian electron distributions and their effect on macroscopic parameters. Research includes theory, particle- in-cell simulation, and experimental investigations. Sheath heating theory and simulation results for electropositive plasmas are used as guide. The investigation was centered on, but not limited to, study of oxygen feedstock gas in capacitively and inductively coupled rf discharges.

  14. Polymeric packaging for fully implantable wireless neural microsensors.

    Science.gov (United States)

    Aceros, Juan; Yin, Ming; Borton, David A; Patterson, William R; Bull, Christopher; Nurmikko, Arto V

    2012-01-01

    We present polymeric packaging methods used for subcutaneous, fully implantable, broadband, and wireless neurosensors. A new tool for accelerated testing and characterization of biocompatible polymeric packaging materials and processes is described along with specialized test units to simulate our fully implantable neurosensor components, materials and fabrication processes. A brief description of the implantable systems is presented along with their current encapsulation methods based on polydimethylsiloxane (PDMS). Results from in-vivo testing of multiple implanted neurosensors in swine and non-human primates are presented. Finally, a novel augmenting polymer thin film material to complement the currently employed PDMS is introduced. This thin layer coating material is based on the Plasma Enhanced Chemical Vapor Deposition (PECVD) process of Hexamethyldisiloxane (HMDSO) and Oxygen (O(2)).

  15. Short-time plasma surface modification of HDPE powder in a Plasma Downer Reactor - process, wettability improvement and ageing effects

    Energy Technology Data Exchange (ETDEWEB)

    Arpagaus, C. [ETH Swiss Federal Institute of Technology Zurich, Institute of Process Engineering, Department of Mechanical and Process Engineering, ETH Zentrum, Sonneggstrasse 3, CH-8092 Zurich (Switzerland); Rossi, A. [ETH Swiss Federal Institute of Technology Zurich, Laboratory for Surface Science and Technology, Department of Materials, ETH Hoenggerberg, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich (Switzerland); Universita degli Studi di Cagliari, Dipartimento di Chimica Inorganica ed Analitica, UdR INSTM I-09100 Cagliari (Italy); Rudolf von Rohr, Ph. [ETH Swiss Federal Institute of Technology Zurich, Institute of Process Engineering, Department of Mechanical and Process Engineering, ETH Zentrum, Sonneggstrasse 3, CH-8092 Zurich (Switzerland)]. E-mail: vonrohr@ipe.mavt.ethz.ch

    2005-12-15

    The effectiveness of improving the wettability of HDPE powders within less than 0.1 s by plasma surface modification in a Plasma Downer Reactor is investigated. A correlation is revealed between the XPS results (O/C-ratio) and the wettability (contact angle, polar surface tension by capillary rise method). The O{sub 2}-content in the plasma feed gas has been adjusted for best wettability properties. XPS results indicate the formation of C=O and COOH functional groups on the powder surface. The O/C-ratio increased from 0.0 (no oxygen on the non-treated powder) up to 0.15 for the plasma treated HDPE powder surface. With pure O{sub 2}-plasma treatment, a water contact angle reduction from >90{sup o} (no water penetration into the untreated PE powder) down to 65{sup o} was achieved. The total surface free energy increased from 31.2 to 45 mN/m. Ageing of treated powders occurs and proceeds mostly within the first 7 days of storage. Contact angle measurements and O1s/O2s intensity ratio data support that ageing is mainly a diffusion-controlled process. Nevertheless, XPS results show the presence of oxygen functional groups even after 40 days, which explains why the powder is still dispersible in water without any addition of surfactants.

  16. Temperature of hydrogen radio frequency plasma under dechlorination process of polychlorinated biphenyls

    Science.gov (United States)

    Inada, Y.; Abe, K.; Kumada, A.; Hidaka, K.; Amano, K.; Itoh, K.; Oono, T.

    2014-10-01

    It has been reported that RF (radio frequency) hydrogen plasmas promote the dechlorination process of PCBs (polychlorinated biphenyls) under irradiation of MW (microwave). A relative emission intensity spectroscope system was used for single-shot imaging of two-dimensional temperature distributions of RF hydrogen plasmas generated in chemical solutions with several mixing ratios of isopropyl alcohol (IPA) and insulation oil under MW irradiation. Our experimental results showed that the plasma generation frequencies for the oil-contaminating solutions were higher than that for the pure IPA solution. In addition, the plasma temperature in the compound liquids including both oil and IPA was higher than that in the pure IPA and oil solutions. A combination of the plasma temperature measurements and plasma composition analysis indicated that the hydrogen radicals generated in a chemical solution containing the equal volumes of IPA and oil were almost the same amounts of H and H+, while those produced in the other solutions were mainly H.

  17. Synthesis and texturization processes of (super)-hydrophobic fluorinated surfaces by atmospheric plasma

    CERN Document Server

    Hubert, Julie; Dufour, Thierry; Vandencasteele, Nicolas; Reniers, François; Viville, Pascal; Lazzaroni, Roberto; Raes, M; Terryn, Herman

    2016-01-01

    The synthesis and texturization processes of fluorinated surfaces by means of atmospheric plasma are investigated and presented through an integrated study of both the plasma phase and the resulting material surface. Three methods enhancing the surface hydrophobicity up to the production of super-hydrophobic surfaces are evaluated: (i) the modification of a polytetrafluoroethylene (PTFE) surface, (ii) the plasma deposition of fluorinated coatings and (iii) the incorporation of nanoparticles into those fluorinated films. In all the approaches, the nature of the plasma gas appears to be a crucial parameter for the desired property. Although a higher etching of the PTFE surface can be obtained with a pure helium plasma, the texturization can only be created if O2 is added to the plasma, which simultaneously decreases the total etching. The deposition of CxFy films by a dielectric barrier discharge leads to hydrophobic coatings with water contact angles (WCAs) of 115{\\textdegree}, but only the filamentary argon d...

  18. Polymerization rate and mechanism of ultrasonically initiated emulsion polymerization of n-butyl acrylate.

    Science.gov (United States)

    Xia, Hesheng; Wang, Qi; Liao, Yongqin; Xu, Xi; Baxter, Steven M; Slone, Robert V; Wu, Shuguang; Swift, Graham; Westmoreland, David G

    2002-07-01

    The factors affecting the induction period and polymerization rate in ultrasonically initiated emulsion polymerization of n-butyl acrylate (BA) were investigated. The induction period takes only an instant in ultrasonically initiated emulsion polymerization of BA without any added initiator by enhancing the N2 flow rate. Increasing temperature, power output and SDS concentration, decreasing the monomer concentration results in further decreasing induction period and enhanced polymerization rate. Under optimized reaction conditions the conversion of BA reaches 92% in 11 min. The polymerization rate can be controlled by varying reaction parameters. The apparatus of ultrasonically initiated semi-continuous and continuous emulsion polymerization were set up and the feasibility was first studied. Based on the experimental results, a free radical polymerization mechanism for ultrasonically initiated emulsion polymerization was proposed, including the sources of the radicals, the process of radical formation, the locus of polymerization and the polymerization process. Compared with conventional emulsion polymerization, where the radicals come from thermal decomposition of a chemical initiator, ultrasonically initiated emulsion polymerization has attractive features such as no need for a chemical initiator, lower reaction temperature, faster polymerization rate, and higher molecular weight of the polymer prepared.

  19. Feature profile evolution in plasma processing using on-wafer monitoring system

    CERN Document Server

    Samukawa, Seiji

    2014-01-01

    This book provides for the first time a good understanding of the etching profile technologies that do not disturb the plasma. Three types of sensors are introduced: on-wafer UV sensors, on-wafer charge-up sensors and on-wafer sheath-shape sensors in the plasma processing and prediction system of real etching profiles based on monitoring data. Readers are made familiar with these sensors, which can measure real plasma process surface conditions such as defect generations due to UV-irradiation, ion flight direction due to charge-up voltage in high-aspect ratio structures and ion sheath conditions at the plasma/surface interface. The plasma etching profile realistically predicted by a computer simulation based on output data from these sensors is described.

  20. Method for atmospheric pressure reactive atom plasma processing for surface modification

    Science.gov (United States)

    Carr, Jeffrey W.

    2009-09-22

    Reactive atom plasma processing can be used to shape, polish, planarize and clean the surfaces of difficult materials with minimal subsurface damage. The apparatus and methods use a plasma torch, such as a conventional ICP torch. The workpiece and plasma torch are moved with respect to each other, whether by translating and/or rotating the workpiece, the plasma, or both. The plasma discharge from the torch can be used to shape, planarize, polish, and/or clean the surface of the workpiece, as well as to thin the workpiece. The processing may cause minimal or no damage to the workpiece underneath the surface, and may involve removing material from the surface of the workpiece.

  1. Solution processed organic light-emitting diodes using the plasma cross-linking technology

    Science.gov (United States)

    He, Kongduo; Liu, Yang; Gong, Junyi; Zeng, Pan; Kong, Xun; Yang, Xilu; Yang, Cheng; Yu, Yan; Liang, Rongqing; Ou, Qiongrong

    2016-09-01

    Solution processed multilayer organic light-emitting diodes (OLEDs) present challenges, especially regarding dissolution of the first layer during deposition of a second layer. In this work, we first demonstrated a plasma cross-linking technology to produce a solution processed OLED. The surfaces of organic films can be cross-linked after mixed acetylene and Ar plasma treatment for several tens of seconds and resist corrosion of organic solvent. The film thickness and surface morphology of emissive layers (EMLs) with plasma treatment and subsequently spin-rinsed with chlorobenzene are nearly unchanged. The solution processed triple-layer OLED is successfully fabricated and the current efficiency increases 50% than that of the double-layer OLED. Fluorescent characteristics of EMLs are also observed to investigate factors influencing the efficiency of the triple-layer OLED. Plasma cross-linking technology may open up a new pathway towards fabrication of all-solution processed multilayer OLEDs and other soft electronic devices.

  2. Plasma processes in the preparation of lithium-ion battery electrodes and separators

    Science.gov (United States)

    Nava-Avendaño, J.; Veilleux, J.

    2017-04-01

    Lithium-ion batteries (LIBs) are the energy storage devices that dominate the portable electronic market. They are now also considered and used for electric vehicles and are foreseen to enable the smart grid. Preparing batteries with high energy and power densities, elevated cycleability and improved safety could be achieved by controlling the microstructure of the electrode materials and the interaction they have with the electrolyte over the working potential window. Selecting appropriate precursors, reducing the preparation steps and selecting more efficient synthesis methods could also significantly reduce the costs of LIB components. Implementing plasma technologies can represent a high capital investment, but the versatility of the technologies allows the preparation of powdered nanoparticles with different morphologies, as well as with carbon and metal oxide coatings. Plasma technologies can also enable the preparation of binder-free thin films and coatings for LIB electrodes, and the treatment of polymeric membranes to be used as separators. This review paper aims at highlighting the different thermal and non-thermal plasma technologies recently used to synthesize coated and non-coated active materials for LIB cathodes and anodes, and to modify the surface of separators.

  3. 等离子体诱导下丙烯酸在 PET 表面的接枝聚合%Grafting Polymerization of Acrylic Acid onto Pet Films by Plasma Inducement

    Institute of Scientific and Technical Information of China (English)

    赵丽娜; 孟宪辉; 刘晓芳; 王继库

    2014-01-01

    利用等离子体对聚对苯二甲酸乙二酯(PET)薄膜进行表面处理,并诱导引发丙烯酸(AAc)在其表面接枝聚合,制备了具有结合牢固、高亲水性的聚丙烯酸( PAAc-g-PET)复合膜。通过表面衰减全反射-傅里叶红外光谱( ATR-FTIR)结构表征,证明了PAAc成功接枝到PET薄膜上。通过对AAc在PET薄膜表面接枝率的动力学影响因素的系统分析,获得了高接枝率下的PAAc-g-PET复合膜的最佳实现条件。%The copolymerization of poly ethylene terephthalate ( PET) films with acrylic acid ( AAc) initiated by air plasma treatment was carried out in our work.Plasma-induced graft polymerization of AAc onto PET films was performed by low temperature plasma after surface treatment of PET films.The strcture and properties of the PET films were investigated by ATR-FTIR and contact angle measurements.PET films pretreated by plasma were subjected to further surface modification by grafting AAc on their surface.Surface morphology of PAAc grafted onto PET films exhibited relatively uniform size distribution.

  4. Organization by Gordon Research Conferences of the 2012 Plasma Processing Science Conference 22-27 July 2012

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Jane

    2012-07-27

    The 2012 Gordon Research Conference on Plasma Processing Science will feature a comprehensive program that will highlight the most cutting edge scientific advances in plasma science and technology as well as explore the applications of this nonequilibrium medium in possible approaches relative to many grand societal challenges. Fundamental science sessions will focus on plasma kinetics and chemistry, plasma surface interactions, and recent trends in plasma generation and multi-phase plasmas. Application sessions will explore the impact of plasma technology in renewable energy, the production of fuels from renewable feedstocks and carbon dioxide neutral solar fuels (from carbon dioxide and water), and plasma-enabled medicine and sterilization.

  5. Rapid Sterilization of Escherichia coli by Solution Plasma Process

    Science.gov (United States)

    Andreeva, Nina; Ishizaki, Takahiro; Baroch, Pavel; Saito, Nagahiro

    2012-12-01

    Solution plasma (SP), which is a discharge in the liquid phase, has the potential for rapid sterilization of water without chemical agents. The discharge showed a strong sterilization performance against Escherichia coli bacteria. The decimal value (D value) of the reduction time for E. coli by this system with an electrode distance of 1.0 mm was estimated to be approximately 1.0 min. Our discharge system in the liquid phase caused no physical damage to the E. coli and only a small increase in the temperature of the aqueous solution. The UV light generated by the discharge was an important factor in the sterilization of E. coli.

  6. Dynamics of electronegative plasmas for materials processing. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lichtenberg, A.J.; Lieberman, M.A.

    1996-12-31

    The purpose of this project is to study the equilibrium particle and energy balance and the heating mechanisms in electronegative r.f. discharges. Particular attention is given to the formation of non-Maxwellian electron distributions and their effect on the macroscopic parameters. The research includes theory, particle-in-cell simulation, and experimental investigations. The sheath heating theory and the simulation results developed for electropositive plasmas are used to guide the investigations. The investigation was centered on, but is not limited to, the study of oxygen feedstock gas in capacitively and inductively coupled r.f. discharges. 15 refs.

  7. High temperature structural, polymeric foams from high internal emulsion polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Hoisington, M.A.; Duke, J.R.; Apen, P.G.

    1996-02-01

    In 1982, a high internal phase emulsion (HIPE) polymerization process to manufacture microcellular, polymeric foam systems was patented by Unilever. This patent discloses a polymerization process that occurs in a water-in-oil emulsion in which the water represents at least 76% of the emulsion by volume. The oil phase consists of vinyl monomers such as styrene and acrylates that are crosslinked by divinyl monomers during polymerization. After polymerization and drying to remove the water phase, the result is a crosslinked polymer foam with an open cell microstructure that is homogeneous throughout in terms of morphology, density, and mechanical properties. Since 1982, numerous patents have examined various HIPE polymerized foam processing techniques and applications that include absorbents for body fluids, cleaning materials, and ion exchange systems. All the published HIPE polymerized foams have concentrated on materials for low temperature applications. Copolymerization of styrene with maleic anhydride and N-substituted maleimides to produce heat resistant thermoplastics has been studied extensively. These investigations have shown that styrene will free radically copolymerize with N-substituted maleimides to create an alternating thermoplastic copolymer with a Tg of approximately 200{degrees}C. However, there are many difficulties in attempting the maleimide styrene copolymerization in a HIPE such as lower polymerization temperatures, maleimide solubility difficulties in both styrene and water, and difficulty obtaining a stable HIPE with a styrene/maleimide oil phase. This work describes the preparation of copolymer foams from N-ethylmaleimide and Bis(3-ethyl-5-methyl-4-maleimide-phenyl)methane with styrene based monomers and crosslinking agents.

  8. Characteristics of Plasma Shock Waves Generated in the Pulsed Laser Ablation Process

    Institute of Scientific and Technical Information of China (English)

    李智华; 张端明; 郁伯铭; 关丽

    2002-01-01

    We modify the Sedov theory to describe plasma shock waves generated in a pulsed laser ablating process. We also study the propagation characteristics of plasma shock waves during the preparation process of functional thin films deposited by a pulsed laser. In particular, we discuss in detail the temporal behaviour of energy causing the difference of the propagation characteristics between the plasma shock wave and the ideal shock wave in the point explosion model. Under the same experimental conditions, the theoretical results calculated with our modified Sedov theory are in good agreement with the existing experimental data.

  9. Numerical Simulation on Expansion Process of Ablation Plasma Induced by Intense Pulsed Ion Beam

    Institute of Scientific and Technical Information of China (English)

    TAN Chang; LIU Yue; WANG Xiao-Gang; MA Teng-Cai

    2006-01-01

    We present a one-dimensional time-dependent numerical model for the expansion process of ablation plasmainduced by intense pulsed ion beam(IPIB).The evolutions of density,velocity,temperature,and pressure of theablation plasma of the aluminium target are obtained.The numerical results are well in agreement with therelative experimental data.It is shown that the expansion process of ablation plasma induced by IPIB includesstrongly nonlinear effects and that shock waves appear during the propagation of the ablation plasma.

  10. Recent developments in plasma spray processes for applications in energy technology

    Science.gov (United States)

    Mauer, G.; Jarligo, M. O.; Marcano, D.; Rezanka, S.; Zhou, D.; Vaßen, R.

    2017-03-01

    This work focuses on recent developments of plasma spray processes with respect to specific demands in energy technology. High Velocity Atmospheric Plasma Spraying (HV-APS) is a novel variant of plasma spraying devoted to materials which are prone to oxidation or decomposition. It is shown how this process can be used for metallic bondcoats in thermal barrier coating systems. Furthermore, Suspension Plasma Spraying (SPS) is a new method to process submicron-sized feedstock powders which are not sufficiently flowable to feed them in dry state. SPS is presently promoted by the development of novel torch concepts with axial feedstock injection. An example for a columnar structured double layer thermal barrier coating is given. Finally, Plasma Spray-Physical Vapor Deposition (PS-PVD) is a novel technology operating in controlled atmosphere at low pressure and high plasma power. At such condition, vaporization even of high-melting oxide ceramics is possible enabling the formation of columnar structured, strain tolerant coatings with low thermal conductivity. Applying different conditions, the deposition is still dominated by liquid splats. Such process is termed Low Pressure Plasma Spraying-Thin Film (LPPS-TF). Two examples of applications are gas-tight and highly ionic and electronic conductive electrolyte and membrane layers which were deposited on porous metallic substrates.

  11. What can we learn about HiPIMS process from the multidimensional plasma modeling?

    Science.gov (United States)

    Minea, Tiberiu

    2016-09-01

    The modeling of PVD process and especially magnetron plasma is widely reported. The novel way to excite the plasma applying to the cathode very high power pulses brings the temporal dimension to the system together with new phenomena. From the kinetic model of the dense plasma region, so called Ionization Region - IR, one can quantify the global behavior of the plasma parameters during the pulse. The most significant are the plasma composition, especially in the case of reactive gases, the fraction of back-attracted sputtered ions, the rarefaction due to wind effect, but also the discharge heating mechanisms and contribution to the discharge current. From the 2D particle modeling of the plasma new insights are revealed concerning the shape of the dense plasma region, the time evolution of the sheath, the electron energy distribution function, but also the characteristics of the diffusion plasma facing the substrate. Adding the third dimension to the model, the results reveal the complex transport of electrons especially in the azimuthal direction (instabilities and drifts), the formation of spokes and flares, and the strong relation between the secondary emission of electrons from the target and the plasma structuring. Warm thanks to Peter Awakowicz and Ante Hecimovic for inviting me to this GEC edition.

  12. Elevated Plasma Homocysteine Level in Vascular Dementia Reflects the Vascular Disease Process

    Directory of Open Access Journals (Sweden)

    Karin Nilsson

    2013-02-01

    Full Text Available Background: Patients with vascular dementia (VaD exhibit particularly elevated levels of plasma total homocysteine (tHcy compared to patients with other psychogeriatric diseases. Methods: We investigated the main determinants (age, renal impairment, cobalamin/folate status and presence of extracerebral vascular disease of plasma tHcy in 525 patients with VaD. Furthermore, 270 patients with depression were used as a reference group to reveal the potential specificity of elevated plasma tHcy in patients with VaD. Results: Elevated plasma tHcy levels in patients with VaD could only partly be attributed to cobalamin/folate deficiency or renal impairment. Plasma tHcy might also be related to the vascular disease process since patients with depression and vascular disease exhibited similar plasma tHcy levels to patients with VaD. Conclusion: Our findings suggest that elevated plasma tHcy might be a sensitive marker for the vascular disease process in patients with VaD and that the level also is a reflection of changes in the other main determinants of plasma tHcy.

  13. A Study of Impedance Relationships in Dual Frequency PECVD Process Plasma

    Science.gov (United States)

    Keil, Douglas; Augustyniak, Edward; Sakiyama, Yukinori; Pecvd/Ald Team

    2016-09-01

    Commercial plasma process reactors are commonly operated with a very limited suite of on-board plasma diagnostics. However, as process demands advance so has the need for detailed plasma monitoring and diagnosis. The VI probe is one of the few instruments commonly available for this task. We present a study of voltage, current, impedance and phase trends acquired by off-the-shelf VI probes in Dual Frequency (DF) 400 kHz/13.56MHz capacitively-coupled plasma (CCP) as typically used for Plasma Enhanced Chemical Vapor Deposition (PECVD). These plasmas typically operate at pressures from 1 to 5 Torr and at RF power levels of 3 W/cm2. Interpretation of DF VI probe impedance trends is challenging. Non-linear interactions are known to exist in plasma impedance scaling with low and high frequency RF power. Simple capacitive sheath models typically do not simultaneously reproduce the impedance observed at each drive frequency. This work will compare VI probe observed DF CCP impedance tends with plasma fluid simulation. Also explored is the agreement seen with sheath models presently available in the literature. Prospects for the creation of useful equivalent circuit models is also discussed.

  14. INVESTIGATION OF MODIFICATION PROCESSES IN RESPECT OF WEAR-RESISTANT PLASMA COATINGS USING PULSE-PLASMA MACHINING

    Directory of Open Access Journals (Sweden)

    V. A. Okovity

    2009-01-01

    Full Text Available The paper contains information on the investigated processes and optimized technological parameters  of  highly-energy  machining of plasma  coatings  made  of  cladding  composite  powders obtained as a result of self-spreading high-temperature synthesis. Metallographic analysis has been carried out and coating properties machined at optimum regimes have been investigated in the paper

  15. Investigation of the plasma processability of natural carbon bearing formations

    Science.gov (United States)

    Molchanov, V. P.

    2017-01-01

    In the south of the Russian Far East, a new perspective source of minerals was pioneered, which is the metal-bearing high carbon rocks of the Ruzhinskaya square. The rocks are rich in crystalline graphite, gold, platinum and carbon nanostructures (fullerene, nanotubes and diamond-like carbon). The technique of extraction of ultrapure (99.98%) crystalline graphite from these rocks has been developed using hydrometallugical methods. The obtained graphite was used as a raw material for plasma-chemical tests succeeded in the separation of nanodimensional carbon structures, part of which could be inherited from the natural graphite-bearing rocks. The results of investigation will be used in the development of resource-saving technology of minerals extraction.

  16. Collisional processes of interest in MFE plasma research

    Energy Technology Data Exchange (ETDEWEB)

    Olson, R.E.

    1990-05-24

    Research on this grant is devoted to the calculation of heavy particle collision cross sections needed for diagnostic studies of magnetic fusion plasmas. This work requires the development and testing of new theoretical methods, with the implementation of benchmarked techniques to collisions pertinent to fusion reactors. Within the last context, we have provided charge-exchange-recombination cross sections to specific n,1-levels for diagnostic studies on TFTR and for a major compilation for IAEA. We have also completed a cross section study related to the planned neutral beam current drive for ITER. In addition, calculations were completed to assess the use of He neutral atom angular scattering measurements for JT-60. Also, new theoretical methods have been developed to more accurately calculate cross sections involving either He or H{sub 2} targets and partially stripped multiply-charged ions.

  17. Influence and Analysis of Concentrate Degree of Plasma Arc for Heat Process of Hardening Treatment

    Institute of Scientific and Technical Information of China (English)

    WANGShuo-gui; YANHong-ri

    2004-01-01

    According to the practicable model of the plasma arc surtace quench, the influence law ot me heat process, cooling course, temperature field about surface quench treatment by plasma arc due to the concentrate degree of plasma arc heat source are discussed in this paper. It shows that the concentrate degree of plasma arc heat source can change the width of the hardening zone and can not change the maximum harden depth. With the increase of the concentrate degree, the area of the heat influence zone is decreased and its shape is narrowed after the heat source. Relative to cooling rate, the influence of the heat source concentrate degree for heat absorption is bigger. The correctness of the practical model are proved with experimental results for quench hardening of 45# steel by plasma arc.

  18. PREFACE: 13th High-Tech Plasma Processes Conference (HTPP-2014)

    Science.gov (United States)

    2014-11-01

    The High-Tech Plasma Processes - 13th European Plasma Conference (HTPP-2014) was held in Toulouse (France) on 22-27 June 2014. The conference series started in 1990 as a thermal plasma conference and has gradually expanded to include other related topics. Now the High-Tech Plasma Processes - European Plasma Conference (HTPP) is an international conference organised in Europe every two years with topics encompassing the whole field of plasma processing science. The aim of the conference is to bring different scientific communities together, to facilitate contacts between science, technology and industry and to provide a platform for the exploration of both the fundamental topics and new applications of plasmas. For this edition of HTPP, as was the case for the last, we have acheived a well balanced participation from the communities of both thermal and non-thermal plasma researchers. 142 people from 17 countries attended the conference with the total number of contributions being 155, consisting of 8 plenary and 8 invited talks plus 51 oral and 88 poster contributions. We have received numerous papers corresponding to the contributions of HTPP-2014 that have been submitted for publication in this volume of Journal of Physics: Conference Series. Each submitted contribution has been peer reviewed (60 referees with at least two reviewing each paper) and the Editors are very grateful to the referees for their careful support in improving the original manuscripts. In total, 52 manuscripts have been accepted for publication covering a range of topics of plasma processing science from plasma fundamentals to process applications through to experiments, diagnostics and modelling. We have grouped the papers into the following 5 topics: - Arc-Materials Interaction and Metallurgy - Plasma Torches and Spraying - Synthesis of Powders and Nanomaterials - Deposition and Surface Treatment - Non-Equilibrium Plasmas We deeply thank the authors for their enthusiastic and high

  19. In-situ polymerized cellulose nanocrystals (CNC)-poly(l-lactide) (PLLA) nanomaterials and applications in nanocomposite processing.

    Science.gov (United States)

    Miao, Chuanwei; Hamad, Wadood Y

    2016-11-20

    CNC-PLLA nanomaterials were synthesized via in-situ ring-opening polymerization of l-lactide in the presence of CNC, resulting in hydrophobic, homogeneous mixture of PLLA-grafted-CNC and free PLLA homopolymer. The free PLLA serves two useful functions: as barrier to further prevent PLLA-g-CNC from forming aggregates, and in creating improved interfacial properties when these nanomaterials are blended with other polymers, hence enhancing their performance. CNC-PLLA nanomaterials can be used for medical or engineering applications as-they-are or by compounding with suitable biopolymers using versatile techniques, such as solution casting, co-extrusion or injection molding, to form hybrid nanocomposites of tunable mechanical properties. When compounded with commercial-grade PLA, the resulting CNC-PLA nanocomposites appear transparent and have tailored (dynamic and static) mechanical and barrier properties, approaching those of poly(ethylene terephthalate), PET. The effect of reaction conditions on the properties of CNC-PLLA nanomaterials have been carefully studied and detailed throughout the paper.

  20. The Microstructure Analysis of Barium M- Hexaferrite Particles Coated by Pani Conducting Material with In Situ Polymerization Process

    Science.gov (United States)

    Zainuri, M.; Amalia, L.

    2017-05-01

    Barium M-Hexaferrite (BaM) was synthesized by coprecipitation method and doped with Zn. Polyaniline (PANI) was synthesized by chemically and doped DBSA. The composite of PANI/BaM was synthesized by in situ polymerization method. The phase identification of the sample was performed by XRD, FTIR and SEM. Based on XRD data, the phase composition of BaM and hematite are 85.52 % and 14.48%. The characteristic peaks of PANI occur at 3435, 1637, 1473, 1298, 1127, 1009, and 799 cm-1. The characteristic metal oxide stretching peaks of BaM occurs at 575 and 437 cm-1. There is no phase changing in PANI/BaM composite. Based on SEM photography, the shape of BaM is hexagonal. The particle size of BaM powder ranges from 400-700 nm. The qualitative interfacial bonding between PANI and BaM particles are conducted very well and the both materials have good wettability.