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Investigations on the layer growth of plasma polymerized HMDSO coatings on micro‐structured polycarbonate (PC) samples
Author(s) -
Michaeli Walter,
Fonteiner Ingrid,
Jüntgen Tim,
Jansen Elmar
Publication year - 2000
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/1439-2054(20000801)280:1<26::aid-mame26>3.0.co;2-9
Subject(s) - hexamethyldisiloxane , materials science , polycarbonate , layer (electronics) , plasma polymerization , composite material , polymerization , coating , substrate (aquarium) , plasma , polymer chemistry , polymer , oceanography , physics , quantum mechanics , geology
In this paper the growing process of plasma polymerized layers on micro‐structured polycarbonate (PC) samples has been investigated. In order to create micro‐structured surfaces, small samples (10×10 mm 2 ) of extruded PC (Makrolon, Bayer AG) were scratched with triangular notches (0,5–10 μm in width) and samples with elevated rectangular structures (height: 1 μm, width: 1–10 μm) were injection‐molded. These structured surfaces were coated by means of plasma polymerization of hexamethyldisiloxane (pp‐HMDSO) or hexamethyldisiloxane/oxygen mixtures (pp‐HMDSO/O 2 ). Essentially both pp‐HMDSO and pp‐HMDSO/O 2 layers showed the same growth mechanisms on the substrate defects. After a certain coating time, a complete closure/coverage of the investigated structures (notches or rectangular elevates) or of the layers deposited on them was observed, which made the sample surface look smoother. The layer thickness that is necessary for this effect depended on the lateral extension of the defect and on the process gases. A characteristic quantity to describe this effect is the ratio r between the layer thickness d and the width of the triangular notch or distance between the rectangular structures w ( r = d / w ), which is significantly dependent on the process gas composition and the geometry of the structure. For triangular notches coated with pp‐HMDSO for example, a change from open to closed structures was observed at r ≈ 1, respectively r ≈ 1,4 for pp‐HMDSO/O 2 coatings under similar process parameters.