Paper Title
Doppler Broadening Positron Annihilation Analysis and Desalination Efficiency of Reverse-Osmosis Polyamide Membranes

Abstract
Two commercial polyamide (PA) thin film composites with different PA cross-linking densities were examined on the morphology, chemical structure, Doppler broadening positron annihilation spectroscopy, and salt desalination performance. The highly cross-linked AG sample resulted in a higher salt rejection but slightly lower water permeance. Meanwhile the highly cross-linked sample showed a smaller S parameter than the loosely cross-linked one. The interplay between polymer cross-linking structure, salt rejection behavior, and Doppler broadening annihilation spectra is discussed. Index Terms - Cross-linked polyamide, Doppler broadening spectra, interfacial polymerization, salt rejection.