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  • 1
    ISSN: 1432-0630
    Keywords: 61.14 ; 61.16 ; 61.65
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract We report on high-resolution experiments by Scanning Force Microscopy (SFM) indicating the tight folding of neighbouring molecular chains in Poly(Ethylene) (PE) crystals. Ultradrawn PE films were prepared in the stacked lamellar morphology exhibiting crystalline lamellae and amorphous parts. The [001] direction of the lamellae is aligned parallel to the substrate surface resulting in {hk0} planes perpendicular to the symmetry axis of the probing tip. This preparation technique allows the direct observation of the molecular arrangement in polymeric crystals as well as an investigation of the crystalline/amorphous interface by SFM: at lower magnification, crystalline and amorphous parts of the film can be distinguished clearly. High-resolution imaging on the crystalline lamellae reveals a PE pitch height of 0.26±0.02 nm while the interchain spacing measures 0.50±0.02 nm consistent with (100) lattice planes aligned parallel to the substrate surface. Finally, the molecular folding at the edges of the lamellae has been studied. Evidence is found for the adjacent reentry of individual molecules at the edge of (100) surfaces.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 26 (1998), S. 306-315 
    ISSN: 0142-2421
    Keywords: polycarbonate ; SF6 ; plasma ; XPS, SFM ; AFM ; mass spectroscopy ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: A systematic investigation was made of the chemical and morphological influences of SF6 plasma on polycarbonate and the influence of plasma treatment on Al metallization. Mass and ion spectroscopy were used for characterization of the plasma and the etching process. X-ray photoelectron spectroscopy (XPS) measurements were applied for the chemical characterization, while atomic force microscopy (AFM) (static and dynamic mode) served to inspect the surface morphology. All analytical techniques were performed in an ultrahigh vacuum system, in order to prevent the polycarbonate sample from being exposed to ambient air after the plasma treatment. During the etching process we used mass difference spectra to demonstrate the removal of masses 19, 28 and 32 corresponding to HF, CO (N2) and CF. Additionally, the inclusion of fluorine was also observed by this technique.The XPS spectra of polycarbonate surfaces show a significant inclusion of fluorine (C-F, C-F2) and a reduction of the oxygen content after the plasma treatment. Aluminium metallization leads to the formation of an Al-F interlayer; metallic growth of Al is only observed when the metallic layers become thicker than a few nanometres.The AFM investigations have shown that even a short plasma treatment causes changes in morphology (structures with an extension of 20-40 nm). After extended plasma exposure the surface becomes very rough, resulting in poor Al adhesion. On untreated polycarbonate, Al grows in the form of weakly bound clusters, which can only be imaged in the dynamic AFM mode. After plasma treatment, Al grows in the form of well-adhering flat layers without clustering. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
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