Gas-permeation control by PET membranes with nanosized pores

Takahashi, Shuichi*; Yoshida, Masaru; Asano, Masaharu; Nakagawa,Tsutomu*

The poly(ethylen terephthalate)(PET) membrane, which has a membrane thickness of 12m, was used in this study. PET is a polymer widely used for fibers, films and bottles. It was assumed that for PET, which is often used as a gas barrier film, it is easy to effect changes in its gas permeability by modification, such as by ion irradiation. Previously, I reported the effect of heavy ion irradiation on the gas permeation of a PET membrane. A portion of the heavy ion irradiated PET membranes exhibited the Knudsen flow during the gas permeation measurements. As a next step, therefore, I applied an etching technique utilizing NaOH solution to control the nanosized pore of the heavy ion irradiated PET membrane. PET membranes irradiated at a fluence of 310 ions/cm were etched in 6N or 1N NaOH solution at 60C. The etching time was controlled to observe the changes in the gas permeation behavior depended on the etchig. This objective has consequently been used to control the Knudsen flow.