|Title:||Applications of positron annihilation spectroscopy to polymeric membranes||Authors:||Jean Y.C.
|Keywords:||Free volume;Interfacial polymerization;Polymeric membrane;Positron annihilation spectroscopy;Slow positron beam||Issue Date:||2008||Journal Volume:||234||Journal Issue:||1-3||Start page/Pages:||89-98||Source:||Desalination||Abstract:||
Positron annihilation spectroscopy (PAS) coupled with a slow positron beam has been used to study the freevolume depth profile (0-10 £gm) in polymeric membrane systems prepared by the interfacial polymerization method. Doppler broadening energy parameters of annihilation radiation vary as a function of the depth from the surface through multi-layers in polyamide asymmetric membranes prepared under different experimental parameters, such as the time, the temperature, and pH of membrane preparation process of interfacial polymerization. Three layer structures including a skin, a transition, and the porous layers in those asymmetric membrane systems are obtained. Positron annihilation lifetime results provide additional information about free-volume size and distribution in nano- and micro-scale film membrane systems. PAS results are correlated with the pervaporation separation, flux and water wt% in permeate of 70% isopropanol aqueous solution and compared with the SEM images. ? 2008 Elsevier B.V. All rights reserved.
|Appears in Collections:||化學工程學系|
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