AVS 51st International Symposium
    Thin Films Tuesday Sessions
       Session TF1-TuM

Invited Paper TF1-TuM1
Mechanisms of Vapor Permeation Through Multilayer Thin-Films

Tuesday, November 16, 2004, 8:20 am, Room 303C

Session: Thin Films on Flexible and Polymer Substrates
Presenter: G.L. Graff, Pacific Northwest National Laboratory
Authors: G.L. Graff, Pacific Northwest National Laboratory
P.E. Burrows, Pacific Northwest National Laboratory
R.E. Williford, Pacific Northwest National Laboratory
Correspondent: Click to Email
Multi-layer, thin-film organic/inorganic composite barrier layers can achieve water vapor permeation rates (WVTR) of <10@super-5@ g/m@super2@/day at 25°C/40%RH on polyethylene terephthalate. Using both transient and steady-state vapor permeation measurements combined with classical Fickian diffusion models, we determine the mechanism of vapor permeation through such barrier structures and show the importance of an extremely long effective path length for the diffusing gas. We show that the barrier performance obtained is dominated by lag-time (transient) effects, rather than equilibrium diffusion. The implications for further improvement of flexible thin film vapor barriers are discussed.