Semipermeable Membrane From Ionomeric Self-Assembling Block Copolymer

Report No. ARL-TR-2403
Authors: Dawn M. Crawford, Eugene Napadensky, Nora C. Beck Tan, Jim Sloan, David A. Reuschle, David A. Mountz, Kenneth A. Mauritz, Kenneth S. Laverdure, Samuel P. Gido, Weidong Liu and Benjamin Hsiao
Date/Pages: February 2001; 32 pages
Abstract: Morphological studies have been performed on novel polystyrene- polyisobutylene- polystyrene (PS-PlB-PS) triblock copolymer films made by different processes. The PS-PIB-PS films are composed of approximately 30% polystyrene end blocks. Small-angle x-ray scattering (SAXS) and transmission electron microscopy (TEM) confirm that a self-assembled, segregated cylindrical morphology forms in the copolymer. Dynamic mechanical analysis (DMA) is used as a tool to investigate the structure-property relationships in these polymers. Fourier-transform infrared (FTIR) spectroscopy and solvent-sorption studies have validated the membrane transport properties. Modified PS-PJB-PS copolymers have also been characterized. Modifications of the copolymers were carried out by converting approximately 20% of the polystyrene end blocks to styrene-sulfonic acid. The presence of sulfonic acid groups disrupts the morphology and significantly enhances water transport properties. Morphological features of the copolymers are discussed as they relate to mechanical and transport properties.
Distribution: Approved for public release
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Last Update / Reviewed: February 1, 2001