Permeation Studies of Transparent Barrier Coatings

Journal article

Gas transmission rates and activation energies have been tabulated for a wide range of oxides deposited by a variety of techniques on polyethylene terephthalate (PET) substrates. Sputtered coatings were found to possess lower permeabilities compared to evaporated layers. Furthermore, ITO exhibited the highest resistance to oxygen permeation whereas AlOxNy presented the best barrier to water vapor transmission. The permeation of oxygen through these films is dominated by the presence of defects in the oxide layer. For water vapor permeation the mechanism is different and there is strong evidence to suggest that the mechanism entails some kind of chemical interaction of the water molecule with the oxide lattice. In a comparison with literature data, it was found that the gas performance of even the best-deposited coatings resembled those of a membrane with an average pore size >0.4nm, and that improved permeation barriers should be possible if defects in the oxides layers can be avoided.

Authors: Henry, B; Erlat, A; Grovenor, C; Briggs, G; Miyamoto, T

• Journal: Proceedings, Annual Technical Conference - Society of Vacuum Coaters
• Pages: 600-605
• Publication date: 2003-01-01
• ISSN: 0737-5921
• Language: English
• Keywords: Oxygen permeation; Polymer substrate; Permeation barrier coatings; Moisture permeation