This thesis describes research into the utilization of conducting polymer polyaniline
(PAni) as a material for the development of asymmetric hollow fiber membranes for gas
separations. In order to ensure the consistency of the emeraldine base PAni molecular
weight and the quality and purity throughout this research, the fresh batch polymer was
synthesized in-house prior to each hollow fiber spinning. The initial gas permeation test
revealed that the hollow fiber fabricated with high molecular weight PAni was
favourable due to the highly viscous solution prepared with significant polymer chain
entanglement that contributed to the formation of a more desirable membrane structure.
However, the major turn around of the work was the introduction of volatile
tetrahydrofuran (THF) to less volatile N-methyl-2-pyrrolidone (NMP) in the dope
solution that promoted a proper formation of integrally skinned membranes. The
effective removal of THF at a high spinning air gap further improved the fabricated
membrane morphology which consisted of a denser effective skin layer, transition layer
and finely porous substructure with smaller macrovoids. In addition, the spine line
stress-induced orientation at a high air gap was responsible for further stretching the
nascent fiber creating more packed structure that assisted toward improving the gas
separation performance of the membranes. The induced molecular orientation also
resulted in improvement in mechanical properties of the hollow fibers. Polyaniline
derivative was synthesized to overcome the PAni solubility issue and to suppress the
formation of PAni micro-agglomerates in the highly viscous dope solution. Integrallyskinned
hollow fiber membranes were successfully prepared by dry-jet wet spinning
from poly(ortho-anisidine) (POAn) dissolved in NMP and THF system. The bulky methoxy group introduced to the polymer backbone increased both the polymer chain
rigidity and specific free volume of POAn as compared to PAni, producing membranes
with significantly enhanced gas pair separation factors and small gases (hydrogen and
carbon dioxide) permeation rates. The final focus of this study was investigating the
potential effect of the aging process on PAni and its derivative membranes gas
separation and mechanical properties. Poly(o-anisidine) membrane properties were
found to be more stable than polyaniline membranes throughout the aging period,
providing a strong foundation for further investigation of poly(o-anisidine) as a
membrane material for gas separation towards commercial application.