Poly(styrene-4-vinylpyridine) (PS-P4VP) isoporous membranes were prepared
and their properties were evaluated in this research. The solution was prepared by
dissolving PS-P4VP polymer with necessary additives into a 1:1:1 1,4-dioxane –
N,N-dimethyl formamide – tetrahydrofuran (DOX-DMF-THF, DDT) solvent. Then
0.5-1.0 mL of the primary solution was cast onto the non-woven substrate
membrane on a glass slide, evaporated for 15-20 sec and immersed into de-ionized
water for more than 30 min for the solidification of isoporous structure and for the
formation of the primary films, which could be post-processed in different ways for
different tests. The membrane surface presents a well-ordered, hexagonal
self-assembly structure, which is fit for aqueous and gaseous filtration. The pore
size of the isoporous surface is 30~40 nm. The pore size is also sensitive to [H+] in
the solution and a typical pair of S-shape pH-correlation curves with significant
hysteresis was found. Four techniques were tried to improve the properties of the
membranes in this research: 1) 1,4-diiodobutane was introduced to chemically
change the structure as a cross-linking agent. 2) single-wall carbon nanotube
(SWCNT) was linked to the membranes in order to strengthen the stability and rigidity and to reduce the hysteresis. 3) Homo-poly(4-vinylpyridine) (homo-P4VP)
was added and inserted into the PS-P4VP micelles to affect the pore size and surface
structure. 4) Copper acetate (Cu(Ac)2) was used as substitute of dioxane to prepare
the Cu(Ac)2-DMF-THF (CDT) mixed solvent, for a better SWCNT dispersion. All the
possible improvements were judged by the atomic force microscopy (AFM) images,
water and gas flux tests and pH-correlation curves. The introduction of SWCNT was
the most important innovation in this research and is promising in future
applications.
| Date of Award | Jun 2011 |
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| Original language | English (US) |
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| Awarding Institution | - Physical Sciences and Engineering
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| Supervisor | Klaus-Victor Peinemann (Supervisor) |
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