The Experts below are selected from a list of 2682 Experts worldwide ranked by ideXlab platform
Gerald Urban - One of the best experts on this subject based on the ideXlab platform.
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Effect of Plasma Treatments and Plasma-Polymerized Films on the Adhesion of Parylene-C to Substrates
Plasma Processes and Polymers, 2013Co-Authors: Dani Zeniieh, Loic Ledernez, Adeel Bajwa, Gerald UrbanAbstract:This work deals with the most severe limitations of Parylene-C coatings, namely their poor adhesion to the substrate and barrier properties. To address these limitations, the surface properties of the substrate are modified prior to the Parylene deposition step by depositing a nano-film interfacial layer by means of a Plasma Polymerization Process. The multilayer coating was realized using a newly designed, innovative multi-chamber system. Tests of dry adhesion (at 90° and 180°) and electrochemical impedance spectroscopic (EIS) measurements were performed to evaluate the effect of the Plasma pre-Processing. Adhesion strength of 3 and 6.8 N cm−1 were recorded for the 90° and 180° tape tests, respectively, while an impedance level of 107 Ω cm−2 at 100 Hz was registered by EIS measurement.
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swelling and water uptake behavior of nanofilms obtained by a magnetron enhanced Plasma Polymerization Process
Plasma Processes and Polymers, 2013Co-Authors: Michael Bergmann, Dani Zeniieh, Loic Ledernez, Gregory Dame, Gerald UrbanAbstract:This work deals with the water uptake and swelling behavior of magnetron-enhanced Plasma-polymerized nanofilms in an aqueous medium. Those coatings are used in biomedical applications such as implants or contact lenses. The role of water in biomaterial surface science is considered to be of great importance. Water is not only the major molecule in most living organisms (70%) and the carrier of cells but it is also the medium in which biochemical Processes take place. Because of its small size and mobility, water is the first molecule to come in contact with a biomaterial in any clinical application.[1] It is believed, that the degree of polymer swelling strongly affects the interaction of proteins with the surface of the polymer, which determines its biocompatibility. Polymers with a high swelling degree show weak enthalpic interactions with proteins, resulting in a protein-repellency.[2] A new approach is applied, which combines three characterization techniques: dynamic contact angle measurements, optical waveguide spectroscopy, and electrochemical impedance spectroscopy. A relation between the composition of the films and the water and salt transport phenomena through the nanofilm was observed. A higher amount of oxygen in the precursor gas ratio in the Polymerization Process leads to a higher wettability as well as a higher water and salt intrusion. Based on this observation an electrical model was introduced and helped to interpret the experimental results.
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Nanofilms Produced by Magnetron Enhanced Plasma Polymerization from Methane and Oxygen for Coating of Rigid Contact Lenses
Plasma Processes and Polymers, 2013Co-Authors: Michael Bergmann, Loic Ledernez, Gregory Dame, Sebastian Lickert, Frank Widmer, Yvonne Gier, Gerald UrbanAbstract:Although soft contact lenses are more widespread, rigid contact lenses have been around for decades and their materials have been greatly improved, especially in terms of oxygen permeability. Protein adsorption and wettability are, however, complex challenges still faced by both soft and rigid contact lenses (CLs). This study aims at improving these two major attributes by means of a low-pressure magnetron enhanced 15 kHz Plasma Polymerization Process. The wide parameter range of the Process allowed the tailoring of the surface properties and delivered stable, reproducible Plasma coatings. The XPS, FT-IR, WCA, and QCM surface analysis methods were used to study the nanofilms. A contact angle of down to 18° and a protein (lysozyme) adsorption of only 0.2 µg cm−2 were achieved. Some correlations with the more commonly used “PEO-like” coatings helped to explain the measurement results.
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Swelling and Water Uptake Behavior of Nanofilms Obtained by a Magnetron Enhanced Plasma‐Polymerization Process
Plasma Processes and Polymers, 2013Co-Authors: Michael Bergmann, Dani Zeniieh, Loic Ledernez, Gregory Dame, Gerald UrbanAbstract:This work deals with the water uptake and swelling behavior of magnetron-enhanced Plasma-polymerized nanofilms in an aqueous medium. Those coatings are used in biomedical applications such as implants or contact lenses. The role of water in biomaterial surface science is considered to be of great importance. Water is not only the major molecule in most living organisms (70%) and the carrier of cells but it is also the medium in which biochemical Processes take place. Because of its small size and mobility, water is the first molecule to come in contact with a biomaterial in any clinical application.[1] It is believed, that the degree of polymer swelling strongly affects the interaction of proteins with the surface of the polymer, which determines its biocompatibility. Polymers with a high swelling degree show weak enthalpic interactions with proteins, resulting in a protein-repellency.[2] A new approach is applied, which combines three characterization techniques: dynamic contact angle measurements, optical waveguide spectroscopy, and electrochemical impedance spectroscopy. A relation between the composition of the films and the water and salt transport phenomena through the nanofilm was observed. A higher amount of oxygen in the precursor gas ratio in the Polymerization Process leads to a higher wettability as well as a higher water and salt intrusion. Based on this observation an electrical model was introduced and helped to interpret the experimental results.
Susumu Kudo - One of the best experts on this subject based on the ideXlab platform.
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adhesion and alignment of nonparenchymal cells onto a patterned surface with a two step Plasma Polymerization Process
Plasma Processes and Polymers, 2015Co-Authors: Hitoshi Muguruma, Tatsuya Hoshino, Ryosuke Fujita, Takeki Sumii, Susumu KudoAbstract:The precise control for the micropatterning of nonparenchymal cells (endothelial cells; ECs and hepatic stellate cells; HSCs) is useful for regenerative medicine, artificial organs, and cell-based biodevice. The adhesion and alignment of nonparenchymal cells on a micro-patterned surface fabricated by two-step Plasma Polymerization Process were investigated. The first functionalization step involves the deposition of a nitrogen-rich Plasma-polymerized film to render the entire surface a cell-adherent region. Following this, a hydrophobic Plasma-polymerized film is formed through a grid metal mask (hundred-micrometer-sized openings) to renders these areas cell repellent. Imaging ellipsometry showed that groove and ridge patterns 100 μm wide and steps with heights on the scale of tens of nanometers were obtained. EC and HSC culture experiments were conducted on the patterned surfaces. EC rapidly adhered and aligned along the cell-adherent groove of the patterned surface, while it did not adhere to the cell-repellent ridge. HSC patterning succeeded only when the height of the cell-repellent ridge was 20 nm, whereas the patterning failed when the ridge height was 10 nm. This indicates that EC patterning is possible with only a chemical effect, whereas HSC patterning required both a chemical effect and the topological constraints of the patterned surface.
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Adhesion and Alignment of Nonparenchymal Cells onto a Patterned Surface with a Two‐Step Plasma Polymerization Process
Plasma Processes and Polymers, 2015Co-Authors: Hitoshi Muguruma, Tatsuya Hoshino, Ryosuke Fujita, Takeki Sumii, Susumu KudoAbstract:The precise control for the micropatterning of nonparenchymal cells (endothelial cells; ECs and hepatic stellate cells; HSCs) is useful for regenerative medicine, artificial organs, and cell-based biodevice. The adhesion and alignment of nonparenchymal cells on a micro-patterned surface fabricated by two-step Plasma Polymerization Process were investigated. The first functionalization step involves the deposition of a nitrogen-rich Plasma-polymerized film to render the entire surface a cell-adherent region. Following this, a hydrophobic Plasma-polymerized film is formed through a grid metal mask (hundred-micrometer-sized openings) to renders these areas cell repellent. Imaging ellipsometry showed that groove and ridge patterns 100 μm wide and steps with heights on the scale of tens of nanometers were obtained. EC and HSC culture experiments were conducted on the patterned surfaces. EC rapidly adhered and aligned along the cell-adherent groove of the patterned surface, while it did not adhere to the cell-repellent ridge. HSC patterning succeeded only when the height of the cell-repellent ridge was 20 nm, whereas the patterning failed when the ridge height was 10 nm. This indicates that EC patterning is possible with only a chemical effect, whereas HSC patterning required both a chemical effect and the topological constraints of the patterned surface.
Hitoshi Muguruma - One of the best experts on this subject based on the ideXlab platform.
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adhesion and alignment of nonparenchymal cells onto a patterned surface with a two step Plasma Polymerization Process
Plasma Processes and Polymers, 2015Co-Authors: Hitoshi Muguruma, Tatsuya Hoshino, Ryosuke Fujita, Takeki Sumii, Susumu KudoAbstract:The precise control for the micropatterning of nonparenchymal cells (endothelial cells; ECs and hepatic stellate cells; HSCs) is useful for regenerative medicine, artificial organs, and cell-based biodevice. The adhesion and alignment of nonparenchymal cells on a micro-patterned surface fabricated by two-step Plasma Polymerization Process were investigated. The first functionalization step involves the deposition of a nitrogen-rich Plasma-polymerized film to render the entire surface a cell-adherent region. Following this, a hydrophobic Plasma-polymerized film is formed through a grid metal mask (hundred-micrometer-sized openings) to renders these areas cell repellent. Imaging ellipsometry showed that groove and ridge patterns 100 μm wide and steps with heights on the scale of tens of nanometers were obtained. EC and HSC culture experiments were conducted on the patterned surfaces. EC rapidly adhered and aligned along the cell-adherent groove of the patterned surface, while it did not adhere to the cell-repellent ridge. HSC patterning succeeded only when the height of the cell-repellent ridge was 20 nm, whereas the patterning failed when the ridge height was 10 nm. This indicates that EC patterning is possible with only a chemical effect, whereas HSC patterning required both a chemical effect and the topological constraints of the patterned surface.
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Adhesion and Alignment of Nonparenchymal Cells onto a Patterned Surface with a Two‐Step Plasma Polymerization Process
Plasma Processes and Polymers, 2015Co-Authors: Hitoshi Muguruma, Tatsuya Hoshino, Ryosuke Fujita, Takeki Sumii, Susumu KudoAbstract:The precise control for the micropatterning of nonparenchymal cells (endothelial cells; ECs and hepatic stellate cells; HSCs) is useful for regenerative medicine, artificial organs, and cell-based biodevice. The adhesion and alignment of nonparenchymal cells on a micro-patterned surface fabricated by two-step Plasma Polymerization Process were investigated. The first functionalization step involves the deposition of a nitrogen-rich Plasma-polymerized film to render the entire surface a cell-adherent region. Following this, a hydrophobic Plasma-polymerized film is formed through a grid metal mask (hundred-micrometer-sized openings) to renders these areas cell repellent. Imaging ellipsometry showed that groove and ridge patterns 100 μm wide and steps with heights on the scale of tens of nanometers were obtained. EC and HSC culture experiments were conducted on the patterned surfaces. EC rapidly adhered and aligned along the cell-adherent groove of the patterned surface, while it did not adhere to the cell-repellent ridge. HSC patterning succeeded only when the height of the cell-repellent ridge was 20 nm, whereas the patterning failed when the ridge height was 10 nm. This indicates that EC patterning is possible with only a chemical effect, whereas HSC patterning required both a chemical effect and the topological constraints of the patterned surface.
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Organic Plasma Process for simple and substrate-independent surface modification of polymeric BioMEMS devices
Biosensors & bioelectronics, 2004Co-Authors: Atsunori Hiratsuka, Hitoshi Muguruma, Kyong Hoon Lee, Isao KarubeAbstract:Abstract 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 μm ×800 μm) 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.
Arup R. Pal - One of the best experts on this subject based on the ideXlab platform.
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Enhancement of proton conductivity of sulfonated polystyrene membrane prepared by Plasma Polymerization Process
Bulletin of Materials Science, 2014Co-Authors: Bhabesh Kumar Nath, Aziz Khan, Joyanti Chutia, Arup R. Pal, Heremba Bailung, Neelotpal Sen Sarma, Devasish Chowdhury, N. C. AdhikaryAbstract: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 mem- branes 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· 6S cm −1 , measured with the help of potentiostat/galvanostat. The thermogravimetric study of the Plasma polymerized membrane shows the thermal stability up to 140 ◦ C
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tio2 polyaniline nanocomposite films prepared by magnetron sputtering combined with Plasma Polymerization Process
Applied Surface Science, 2011Co-Authors: Arup R. Pal, Joyanti Chutia, Bimal K. Sarma, N. C. Adhikary, H BailungAbstract:Abstract Radiofrequency Plasma Polymerization in combination with direct current reactive magnetron sputtering is utilized for the synthesis of TiO 2 /Plasma polymerized aniline nanocomposite thin films. In the composite film, X-ray diffraction measurements reveal formation of nanocrystalline rutile TiO 2 of crystallite size 3.6 nm. Due to continuous bombardment of Plasma species during simultaneous magnetron sputtering and Plasma Polymerization, the precursors of Polymerization are broken and few functional groups are retained in the composite film. The Plasma polymerized aniline has the direct optical band gap of 3.55 eV and the nanocrystalline rutile TiO 2 is wide gap semiconductor with indirect gap of 3.20 eV which suggests the existence of an energy barrier at the interface in the composite form. The ac conductivity of composite film shows significant improvement as compared to Plasma polymerized aniline film and sputtered rutile TiO 2 film. The composite film may find potential application as antistatic coatings.
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TiO2/polyaniline nanocomposite films prepared by magnetron sputtering combined with Plasma Polymerization Process
Applied Surface Science, 2011Co-Authors: Arup R. Pal, Joyanti Chutia, Bimal K. Sarma, N. C. Adhikary, Heremba BailungAbstract:Abstract Radiofrequency Plasma Polymerization in combination with direct current reactive magnetron sputtering is utilized for the synthesis of TiO 2 /Plasma polymerized aniline nanocomposite thin films. In the composite film, X-ray diffraction measurements reveal formation of nanocrystalline rutile TiO 2 of crystallite size 3.6 nm. Due to continuous bombardment of Plasma species during simultaneous magnetron sputtering and Plasma Polymerization, the precursors of Polymerization are broken and few functional groups are retained in the composite film. The Plasma polymerized aniline has the direct optical band gap of 3.55 eV and the nanocrystalline rutile TiO 2 is wide gap semiconductor with indirect gap of 3.20 eV which suggests the existence of an energy barrier at the interface in the composite form. The ac conductivity of composite film shows significant improvement as compared to Plasma polymerized aniline film and sputtered rutile TiO 2 film. The composite film may find potential application as antistatic coatings.
Joyanti Chutia - One of the best experts on this subject based on the ideXlab platform.
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Enhancement of proton conductivity of sulfonated polystyrene membrane prepared by Plasma Polymerization Process
Bulletin of Materials Science, 2014Co-Authors: Bhabesh Kumar Nath, Aziz Khan, Joyanti Chutia, Arup R. Pal, Heremba Bailung, Neelotpal Sen Sarma, Devasish Chowdhury, N. C. AdhikaryAbstract: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 mem- branes 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· 6S cm −1 , measured with the help of potentiostat/galvanostat. The thermogravimetric study of the Plasma polymerized membrane shows the thermal stability up to 140 ◦ C
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Enhancement of proton conductivity of sulfonated polystyrene membrane prepared by Plasma Polymerization Process
Bulletin of Materials Science, 2014Co-Authors: Bhabesh Kumar Nath, Aziz Khan, Joyanti Chutia, Heremba Bailung, Neelotpal Sen Sarma, Devasish Chowdhury, N. C. AdhikaryAbstract: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 (C_ 8 H _ 8 ) and trifluoromethane sulfonic acid (CF_ 3 SO_ 3 H). 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.
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Modification of surface properties of bell metal by radiofrequency Plasma Polymerization
Journal of Theoretical and Applied Physics, 2012Co-Authors: Joyanti Chutia, Arup Jyoti Choudhury, Arup Ratan Pal, Dolly GogoiAbstract: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.
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tio2 polyaniline nanocomposite films prepared by magnetron sputtering combined with Plasma Polymerization Process
Applied Surface Science, 2011Co-Authors: Arup R. Pal, Joyanti Chutia, Bimal K. Sarma, N. C. Adhikary, H BailungAbstract:Abstract Radiofrequency Plasma Polymerization in combination with direct current reactive magnetron sputtering is utilized for the synthesis of TiO 2 /Plasma polymerized aniline nanocomposite thin films. In the composite film, X-ray diffraction measurements reveal formation of nanocrystalline rutile TiO 2 of crystallite size 3.6 nm. Due to continuous bombardment of Plasma species during simultaneous magnetron sputtering and Plasma Polymerization, the precursors of Polymerization are broken and few functional groups are retained in the composite film. The Plasma polymerized aniline has the direct optical band gap of 3.55 eV and the nanocrystalline rutile TiO 2 is wide gap semiconductor with indirect gap of 3.20 eV which suggests the existence of an energy barrier at the interface in the composite form. The ac conductivity of composite film shows significant improvement as compared to Plasma polymerized aniline film and sputtered rutile TiO 2 film. The composite film may find potential application as antistatic coatings.
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TiO2/polyaniline nanocomposite films prepared by magnetron sputtering combined with Plasma Polymerization Process
Applied Surface Science, 2011Co-Authors: Arup R. Pal, Joyanti Chutia, Bimal K. Sarma, N. C. Adhikary, Heremba BailungAbstract:Abstract Radiofrequency Plasma Polymerization in combination with direct current reactive magnetron sputtering is utilized for the synthesis of TiO 2 /Plasma polymerized aniline nanocomposite thin films. In the composite film, X-ray diffraction measurements reveal formation of nanocrystalline rutile TiO 2 of crystallite size 3.6 nm. Due to continuous bombardment of Plasma species during simultaneous magnetron sputtering and Plasma Polymerization, the precursors of Polymerization are broken and few functional groups are retained in the composite film. The Plasma polymerized aniline has the direct optical band gap of 3.55 eV and the nanocrystalline rutile TiO 2 is wide gap semiconductor with indirect gap of 3.20 eV which suggests the existence of an energy barrier at the interface in the composite form. The ac conductivity of composite film shows significant improvement as compared to Plasma polymerized aniline film and sputtered rutile TiO 2 film. The composite film may find potential application as antistatic coatings.