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  • 1
    Language: English
    In: Thin Solid Films, Oct 31, 2013, Vol.545, p.558(6)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.tsf.2013.07.028 Byline: Magdalena Rohrbeck, Susanne Korsten, Christian B. Fischer, Stefan Wehner, Barbara Kessler Abstract: Bioplastic materials are a promising replacement for petroleum-based plastics. Coating is an often used method to improve characteristics of traditional plastic materials. We present results of the coating of a 50[mu]m thick pure bioplastic foil, a mixture of 92% polyhydroxybutyrate and 8% polyhydroxyvalerate, with diamond-like carbon (DLC) via a radio frequency plasma enhanced chemical vapor deposition process. Two different types of DLC are deposited on the foil, an sp.sup.3-rich (r-DLC) and an sp.sup.2-rich (f-DLC). The first type results in a more robust the second in a more flexible kind of coating. The surface morphologies of layers with various thicknesses are examined, r-DLC up to 1000nm, f-DLC up to 200nm. DLC layers up to around 450nm are intact, further deposition results in cracking and exfoliation of the DLC coating. The exfoliated DLC flakes roll up during the ongoing plasma process. This process is observed again on the thereby newly exposed substrate between the flakes. Rolling of the DLC flakes shows the presence of internal stress in the deposited DLC coating. Article History: Received 8 January 2013; Revised 8 July 2013; Accepted 12 July 2013
    Keywords: Chemical Vapor Deposition ; Coatings
    ISSN: 0040-6090
    Source: Cengage Learning, Inc.
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  • 2
    Language: English
    In: Applied Surface Science, April 15, 2013, Vol.271, p.381(9)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.apsusc.2013.01.210 Byline: Christian B. Fischer (a), Magdalena Rohrbeck (a), Stefan Wehner (a), Matthias Richter (b), Dieter Schmei[sz]er (b) Keywords: Diamond-like carbon; Interlayer formation; Polyethylene; Surface characterization; Coatings; Plastics Abstract: Display Omitted Author Affiliation: (a) Department of Physics, University Koblenz-Landau, 56070 Koblenz, Germany (b) Department of Applied Physics and Sensors, Brandenburg University of Technology, 03046 Cottbus, Germany Article History: Received 19 September 2012; Accepted 31 January 2013
    Keywords: Coatings Industry ; Atomic Force Microscopy ; Coatings ; Polyethylene
    ISSN: 0169-4332
    Source: Cengage Learning, Inc.
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  • 3
    Language: English
    In: Thin Solid Films, 31 October 2013, Vol.545, pp.558-563
    Description: Bioplastic materials are a promising replacement for petroleum-based plastics. Coating is an often used method to improve characteristics of traditional plastic materials. We present results of the coating of a 50 μm thick pure bioplastic foil, a mixture of 92% polyhydroxybutyrate and 8% polyhydroxyvalerate, with diamond-like carbon (DLC) via a radio frequency plasma enhanced chemical vapor deposition process. Two different types of DLC are deposited on the foil, an sp -rich (r-DLC) and an sp -rich (f-DLC). The first type results in a more robust the second in a more flexible kind of coating. The surface morphologies of layers with various thicknesses are examined, r-DLC up to 1000 nm, f-DLC up to 200 nm. DLC layers up to around 450 nm are intact, further deposition results in cracking and exfoliation of the DLC coating. The exfoliated DLC flakes roll up during the ongoing plasma process. This process is observed again on the thereby newly exposed substrate between the flakes. Rolling of the DLC flakes shows the presence of internal stress in the deposited DLC coating.
    Keywords: Polyhydroxybutyrate (Phb) ; Diamond-Like Carbon (DLC) ; Bioplastic ; Plasma Enhanced Chemical Vapor Deposition (Pecvd) ; Scanning Electron Microscopy (SEM) ; Engineering ; Physics
    ISSN: 0040-6090
    E-ISSN: 1879-2731
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  • 4
    Language: English
    In: Applied Surface Science, 15 April 2013, Vol.271, pp.381-389
    Description: ► Interaction of plasma generated carbon with polyethylene material is examined. ► A model for the coating of soft plastic material with hard DLC is presented. ► Interlayer formation between these unequal materials is proven. ► The formation mechanism and thickness depend on the DLC type. ► The interlayer develops during the coating process. The coating of materials with diamond-like carbon (DLC) is a very common way to change and improve their basic characteristics. Although DLC is used on several substrates, the chemical and physical properties throughout the coating process on plastics are yet sparsely investigated. Two types of protective coatings one sp -enriched (robust, r-type) and one with more sp -centers (flexible, f-type) have been realized on polyethylene by PECVD deposition. SEM and AFM analysis of coated samples of DLC types revealed diverse surface topographies on different scales and images appeared even differently smoothed by the carbonaceous deposits. Grains of both DLC types are platelet-shaped and nearly double in size for the robust type indicating fundamental differences in the epitaxial DLC growth. NEXAFS spectroscopy showed significant details of carbon centers in chemically different neighborhood displaying a characteristic fingerprint behavior. Comparison of deposition models revealed a mechanism of interlayer formation which is discussed in detail. Interlayer formation is clearly the appropriate explanation of the process for the current carbon deposition between these two unequal materials. An improved understanding of hard DLC and soft polyethylene assembly is given in the presented work.
    Keywords: Diamond-Like Carbon ; Interlayer Formation ; Polyethylene ; Surface Characterization ; Coatings ; Plastics ; Engineering
    ISSN: 0169-4332
    E-ISSN: 1873-5584
    Source: ScienceDirect Journals (Elsevier)
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  • 5
    Language: English
    In: Vakuum in Forschung und Praxis, April-May, 2014, Vol.26(2), p.42(6)
    Keywords: Atomic Force Microscopy
    ISSN: 0947-076X
    Source: Cengage Learning, Inc.
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  • 6
    Language: English
    In: Vakuum in Forschung und Praxis, April 2014, Vol.26(2), pp.42-47
    Description: Polymers made of renewable resources increasingly replace conventional plastic materials made of petroleum. Socalled bioplastics can be found e. g. in food industry, for agricultural usage or in the medical field. The range of applications can be further expanded with specialized coating of their surface. Especially in case of food packaging and the usage within medical devices as well as the storage of these composite materials, sterilization or at least the partial reduction of microbial growth is an important issue which needs to be addressed early in the production process. In this work, a commercially available polyhydroxyalkanoate (PHA) pure bioplastic foil of 50 μm thickness was coated with 100 nm of diamond‐like carbon (DLC) and afterwards treated by four different standard methods of sterilization and / or disinfection, namely deep‐freezing, ultraviolet irradiation, autoclaving and immersion in ethanol. The surface morphology of treated DLC‐coated and uncoated samples was investigated and compared to the untreated DLC‐coated and uncoated samples using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Measurements exhibited damage of the composite for autoclaved and in ethanol immersed samples, whereas deep‐frozen and ultraviolet irradiated samples showed no structural changes. These findings clearly demonstrate deep‐freezing and ultraviolet irradiation to be appropriate methods for the disinfection and sterilization, respectively, of the DLC‐coated pure bioplastic foil. DLC‐beschichtete Biokunststoff‐Folie — Auswirkungen verschiedener Sterilisationsmethoden auf die Oberflächenmorphologie Aus erneuerbaren Ressourcen hergestellte Polymere ersetzen zunehmend Erdöl‐basierte konventionelle Kunststoffe. Die sogenannten Biokunststoffe sind z. B. in der Nahrungsmittelindustrie, der Landwirtschaft oder der Medizin zu finden. Ihr Anwendungsspektrum kann durch spezielle Oberflächenbeschichtungen aber noch erweitert werden. Insbesondere in der Nahrungsmittelverpackungsindustrie, bei der Verwendung in medizinischen Apparaturen und Implantaten sowie deren Lagerung ist die Sterilisierung oder zumindest die teilweise Reduzierung der mikrobiellen Aktivität ein wichtiger Aspekt, der bereits frühzeitig im Produktionsprozess berücksichtigt werden muss. In der vorliegenden Arbeit wurde kommerziell erhältliche 50 μm dicke Polyhydroxyalkanoat (PHA)‐Biokunststoff‐Folie mit 100 nm diamant‐ähnlichem Kohlenstoff (DLC) beschichtet und danach mit vier verschiedenen Standardmethoden der Sterilisation und/oder Desinfektion, nämlich UV‐Bestrahlung, Autoklavieren, Tiefkühlung, und Eintauchen in Ethanol, behandelt. Die Oberflächenstruktur der so behandelten Proben (DLC‐beschichtet und unbeschichtet) wurde mittels REM (Rasterelektronenmikroskopie) und AFM (Rasterkraftmikroskopie) untersucht und mit den entsprechenden unbehandelten Proben verglichen. Die Messungen ergaben Beschädigungen des Materialverbundes bei der Behandlung durch Autoklavieren und Ethanol, wohingegen die tiefgekühlten und UV‐bestrahlten Proben keinerlei strukturelle Veränderungen zeigten. Diese Ergebnisse zeigen klar, dass Tiefkühlung und UV‐Bestrahlung geeignete Methoden für die Desinfizierung bzw. Sterilisation dieser DLC‐beschichteten Biokunststoff‐Folien darstellen.
    Keywords: Nahrungsmittelindustrie ; Oberflächenbeschichtung ; Sterilisierung ; Produktionsprozess ; Desinfektion ; Tiefkühlen ; Biokunststoff ; Oberflächenmorphologie ; Polymer ; Kunststoff ; Landwirtschaft ; Polyhydroxyalkanoat ; Diamantähnlicher Kohlenstoff ; Ethanol ; Autoklavierung ; Desinfizieren ; Mikrobenwachstum ; Autoklav ; Immersion ; Strukturumwandlung ; Medizinische Anwendung ; Engineering ; Physics;
    ISSN: 0947-076X
    E-ISSN: 1522-2454
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  • 7
    Language: German
    In: Vakuum in Forschung und Praxis, October 2013, Vol.25(5), pp.36-41
    Description: Das Aufwachsen von diamantähnlichem Kohlenstoff (DLC) auf Polyethylene (PE) geht einher mit der Bildung einer Zwischenschicht. Dabei verändert sich die ursprüngliche Oberflächenstruktur des Kunststoffes und geht schrittweise in die ungeordnete Struktur der DLC‐Schicht über. Bevor DLC im Kohlenwasserstoffplasma mittels PECVD‐Methode aufgebracht werden kann, werden alle Substrate unter Verwendung eines Sauerstoffplasmas gereinigt. Dieser erste Teilschritt ist extrem wichtig für das Aufwachsen der DLC‐Schicht, da hierbei die Probenoberfläche bereits abgetragen und teilweise eingeebnet wird. Kunststoffe können durch DLC‐Beschichtung erfolgreich in der Stabilität verbessert und mit zusätzlichen Eigenschaften und neuen Funktionalitäten ausgestattet werden. Erste mikroskopische Erklärungen für die makroskopischen Phänomene und anwendungsrelevante Fragen konnten aufgezeigt werden. Außerdem werden die Grenzen der Machbarkeit thematisiert. Die hier vorgestellten Methoden werden nun auf weitere Materialien und Beschichtungen angewandt. Plasmaenhanced deposition of DLC on polymers The formation of diamond‐like carbon (DLC) coatings on polyethylene (PE) is accompanied with the formation of an interlayer. Therefore the original surface structure of the plastic material is reorganized and gradually changes into the disordered structure of the DLC layer. Before DLC can be deposited in a hydrocarbon plasma with the PECVD method, all substrates are cleaned using an oxygen plasma. This first step is extremely important for the growth of the DLC layer since the sample's surface is already ablated and partly flattened. Plastic materials can be successfully improved in stability and provided with extra properties and new functionalities due to the deposition of DLC. First microscopic explanations for the macroscopic phenomena and application‐relevant questions have been identified. In spite of this limits of production are also addressed. Methods shown here will now be adapted for other materials and coatings.
    Keywords: Flattening ; Interlayers ; Hydrocarbons ; Deposition ; Polyethylenes ; Ablation ; Diamond-Like Carbon Films ; Coatings ; Cryogenics and Vacuum Science (So) ; Finishing (MD) ; Surface Finishing (Ep) ; Surface Finishing (Ed) ; Surface Finishing (EC);
    ISSN: 0947-076X
    E-ISSN: 1522-2454
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