Free positron annihilation lifetime analysis for irradiated polyimide

Hirade, Tetsuya  ; Oka, Toshitaka   ; Morishita, Norio*; Idesaki, Akira; Shimada, Akihiko

Ortho-Ps is an unique probe that the lifetime can give information of microscopic free volume in polymers. Although it is often used for polymer researches, there is no Ps formation in polyimide polymers such as Kapton. Therefore we tried to study the change of free volume of irradiated Kapton by use of a new idea that the change of free volume can be observed by the change of free positron annihilation lifetime. The change of free volume in irradiated Kapton could be discussed by observing the free positron annihilation lifetime instead of ortho-Ps annihilation lifetime.