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Abstract

The influence of amorphous hydrogenated carbon (a-C:H) coatings on the gas permeation through polymer films was investigated. a-C:H films were deposited from a 13.56-MHz RF glow discharge in methane or acetylene atmosphere. Thin poly(ethylene terephthalate) and polyimide foils were used as substrates. The permeation of the gases H(2), N(2), O(2) and CO(2) was measured and the reduction of the permeability coefficient was correlated to composition and density of the a-C:H films. The stoichiometry of the layers was analyzed using ion-beam techniques on films deposited onto silicon samples. The a-C:H/PET surfaces were analyzed using optical microscopy and atomic force microscopy (AFM). Multi-layer structures comprising different types of a-C:H films were also investigated. A reduction of the permeability coefficient by 80% for hard, dense and 94% for soft, polymer-like layers was found. Surprisingly, the barrier efficacy of the coating decreases with increasing a-C:H film density. This unexpected result is attributed to the appearance of a network of deep cracks spread out over the whole coating.

Additional information

Authors: VASQUEZ-BORUCKI S, Programa de Engenharia Metalurgica e de Materials, COPPE, UFRJ 21910-970 Rio de Janeiro, RJ (BR);ACHETE C, Programa de Engenharia Metalurgica e de Materials, COPPE, UFRJ 21910-970 Rio de Janeiro, RJ (BR);JACOB W, Centre for Interdisciplinary Plasma Science, Max-Plank-Institut fur Plasmaphysik,EURATOM-Association, Boltzmannstrasse 2, D-85748 Garching (DE)
Bibliographic Reference: Article:Diamond and Related Materials, Vol. 9 (2000), pp. 1971-1978
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