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Diamond‐like carbon, a barrier coating for polymers used in packaging applications
Author(s) -
Finch D. S.,
Franks J.,
Randall N. X.,
Barnetson A.,
Crouch J.,
Evans A. C.,
Ralph B.
Publication year - 1996
Publication title -
packaging technology and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.365
H-Index - 50
eISSN - 1099-1522
pISSN - 0894-3214
DOI - 10.1002/(sici)1099-1522(199603)9:2<73::aid-pts353>3.0.co;2-o
Subject(s) - materials science , coating , diamond , polymer , diamond like carbon , carbon fibers , composite material , polymer science , nanotechnology , thin film , composite number
Water and oxygen permeability measurements on two polymers, poly(ethylene terephthalate) and polypropylene, are presented as a function of diamond‐like carbon coating thickness. Results show that reliable and reproducible coatings can be achieved on poly(ethylene terephthalate) such that levels of permeability are about 1 cc/m 2 /day for oxygen and 1.5 g/m 2 /day for water vapour, comparable to the levels for silicon oxides and aluminium coatings used in the packaging industry. The advantages conferred by diamond‐like carbon over aluminium is primarily that of retaining optical transparency in the thickness of films used in this work (20 nm). The advantages of diamond‐like carbon over silicon oxides is related to its intrinsic flexibility. Other advantages over other barrier films (e.g. polyvinylidine chloride) and coating technologies is the ability to recycle the used product. The permeability of diamond‐like carbon‐coated polypropylene to oxygen is in the range of 200 cc/m 2 /day, again comparable to results obtained with the other coatings. The optimum film thickness for poly(ethylene terephthalate) to minimize permeability was 20 nm. Atomic force microscopy revealed agglomerated structures (possibly graphitic) with the underlying substrate appearing smoother than the starting material. In comparison, polypropylene exhibited increased surface roughness under the same coating conditions.