Tailoring the morphology of self-assembled block copolymer hollow fiber membranes

POLYMER

卷:55

Article

Radjabian, Maryam¹  Koll, Joachim¹  Buhr, Kristian¹  Vainio, Ulla¹  Abetz, Clarissa¹  Handge, Ulrich A.¹  Abetz, Volker^1,2 

[1] Inst Mat Res, Helmholtz Zentrum Geesthacht, D-21502 Geesthacht, Germany

[2] Univ Hamburg, Inst Phys Chem, D-20146 Hamburg, Germany

关键词: Block copolymer;    Self-assembly;    Hollow fiber membrane;   

DOI  :  10.1016/j.polymer.2014.04.041

来源: Elsevier

【 摘 要 】

Isoporous asymmetric polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) hollow fiber membranes were successfully made by a dry-jet wet spinning process. Well-defined nanometer-scale pores around 20-40 nm in diameter were tailored on the top surface of the fiber above a non-ordered macroporous layer by combining block copolymer self-assembly and non-solvent induced phase separation (SNIPS). Uniformity of the surface-assembled pores and fiber cross-section morphology was improved by adjusting the solution concentration, solvent composition as well as some important spinning parameters such as bore fluid flow rate, polymer solution flow rate and air gap distance between the spinneret and the precipitation bath. The formation of the well-organized self-assembled pores is a result of the interplay of fast relaxation of the shear-induced oriented block copolymer chains, the rapid evaporation of the solvent mixture on the outer surface and solvent extraction into the bore liquid on the lumen side, and gravity force during spinning. Structural features of the block copolymer solutions were investigated by small-angle X-ray scattering (SAXS) and theological properties of the solutions were examined as well. The scattering patterns of the optimal solutions for membrane formation indicate a disordered phase which is very close to the disorder-order transition. The nanostructured surface and cross-section morphology of the membranes were characterized by scanning electron microscopy (SEM). The water flux of the membranes was measured and gas permeation was examined to test the pressure stability of the hollow fibers. (C) 2014 Elsevier Ltd. All rights reserved.

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