Comparison of the Free Volume of LiCl-Added SPPO Membrane and SPPO-PES Blend Membrane by Positron Annihilation Method

摘要

Positron annihilation lifetime spectroscopy (PALS) is a powerful technique for the study of free volume in polymers. The lifetime of ortho-positronium (o-Ps), a bound state of an electron and a positron, can be used to assess the pore size, while the intensity can be used to characterize the number of pores. Based on the values of the long-lived o-Ps components in the lifetime spectra, the radii and fractional free volumes of sulfonated poly (2,6-dimethyl-l,4-phenyleneoxide) (SPPO) membranes with added LiCl and SPPO-PES (Polyethersulfone) blend were compared. Free volume radii in both kinds of membranes are discussed.