Hollow Fibre Spinning of Block Copolymers: Influence of Spinning Conditions on Morphological Properties

Abstract

The self-assembly of block copolymers proposes interesting strategies for design and fabrication of ordered nano/microdomain structures. Recently, large attention has been given to the preparation of porous membranes with cylinder-forming on the top layer of integral asymmetric membranes. In this work, another example of this effort is shown by manufacturing of nanoporous hollow fibre membranes from polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) solutions via phase inversion process. In this way, the self-assembly of block copolymers into an ordered morphology via solvent evaporation is combined with microdomain alignment by shear flow in the die. The influence of the experimental parameters on the morphology of the hollow fibre is discussed, such as type of block copolymer, solution concentration and viscosity, extrusion pressure within the spinneret and air gap distance between the spinneret and the precipitation bath (evaporation time). The evaluation of the surface morphology of the membranes by scanning electron microscopy (SEM) confirms the strong effect of shear flow and solution viscosity on the formation of nanoporous structures in hollow fiber spinning.