• Membrane Journal
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• v.17 no.4
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• pp.329-337
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• 2007

This is the research about a new method to make the internal separation layer with smallest pore size in polyethersulfone (PES) membrane by adding p-toluenesulfonic acid (TSA) and polyvinylpyrolidone (PVP) to polymeric PES solution. The preparation and morphological characterization of PES sheet membranes containing PVP as a hydrophilic swelling material and TSA as a demixing material were performed. As a result by microflow porometery, the PVP and TSA added PES membranes showed good permeabilities and narrow pore size distributions, comparable to those of the commercial membranes. The concentration of PVP affected the PES characteristics on air permeability and surface structure. The concentration of TSA influenced on pore size distribution but do not affect air permeability. The surface images of FE-SEM shows similar pore size when TSA added or not. However, the cross-section images of FE-SEM show that the TSA added PES membranes have a increase of internal layer thickness with smallest pore size.

• Membrane Journal
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• v.19 no.1
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• pp.25-33
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• 2009

PES (polyethersulfone) membranes with highly enhanced their asymmetry were prepared by phase inversion process. The membranes were prepared by using PES/DMF (N,N-dimethylformamide)/TSA (p-toluenesulfonic acid)/PVP (polyvinylpyrrolidone) casting solution and water coagulant. The pre-coagulation of membrane surface which was induced by an addition of TSA as a demixing agent and PVP as a swelling polymer in the PES solution and humid exposure time, played a crucial role in determining morphological properties and the PWP (pure water permeation) performance. The PES solution was coated on polyester film under condition of 80% humidity for a while ($72{\sim}144$ sec) before immersing in a coagulation bath. The characterization of membranes was carried out by a capillary flow porometer, a FE-SEM and a permeation test apparatus. As the thickness of the smallest pore size layer (SPL) decreased, the asymmetry of membrane increased under conditions of 20 wt% of TSA and 10 wt% of PVP in 11 wt% of PES solution during longer humid contact time. As a result, the membranes showed a remarkable increase of PWP.