Session 20: Next Gen Advancements

Water Vapor Transmission Rate (WVTR) Measurements for Ultra-High Barrier Materials used in the Display Industry
Thursday, February 15, 2018
3:05 PM - 3:25 PM

Ultra-high barrier materials have been developed to protect OLED electronics and flexible displays from ambient moisture. These barriers have very low water permeation rates, and require quantitative measurements of WVTR levels down to 10-5 to 10-6 g/(m^2day). This paper will present the use of an absolute Coulometric Sensor to quantitatively measure WVTR directly down to a level of 10-5 g/(m^2day), and with a special setup, measure WVTR indirectly down to a level of 10-6 g/(m^2day). A comparison of WVTR results using this absolute Coulometric Sensor compared to the gravimetric method showed that results were quantitively similar; however, the gravimetric method test took months to complete, whereas the absolute coulometric method obtained comparable results in days. High barrier film samples also can be tested under highly accelerated life testing conditions at 85C and 85%RH using this coulometric method and a custom-designed test fixture. Details of this design will also be presented.