title: Accurate and stable equal-pressure measurements of water vapor transmission rate reaching the 10-6g m-2day-1range.
abstract: The water vapor transmission rate (WVTR) of a gas barrier coating is a critically important parameter for flexible organic device packaging, but its accurate measurement without mechanical stress to ultrathin films has been a significant challenge in instrumental analysis. At the current stage, no reliable results have been reported in the range of 10-6g m-2day-1that is required for organic light emitting diodes (OLEDs). In this article, we describe a solution for this difficult, but important measurement, involving enhanced sensitivity by a cold trap, stabilized temperature system, pumped sealing and calibration by a standard conductance element.
authors.affiliation: Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo, 060-8628, Japan.
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Nakano
authors.affiliation: Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo, 060-8628, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yanase
authors.affiliation: Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo, 060-8628, Japan.
authors.forename: Taro
authors.initials: T
authors.lastname: Nagahama
authors.affiliation: The National Metrology Institute of Japan, The National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba, 305-8560, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Yoshida
authors.affiliation: Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo, 060-8628, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Shimada