Annular hollow fibres were prepared by co-extrusion of two different polyme
r solutions through a triple orifice spinneret. PVDF/NMP/PEG200 and PESf/PV
P/NMP/EgOH were used as inner and outer dope solutions, respectively. Exper
imental conditions on the formation of annular hollow fibres were studied e
xperimentally. Structures of the annular hollow fibres were examined by SEM
. Through the proper selection of dope composition and spinning parameters,
the annular hollow fibre membranes could be formed with controlled width o
f the hollow fibre annulus. Both inner and enter layers of the annular holl
ow fibre possess open ended finger-like cavities facing to the annulus with
its mouth diameters of about 20 mum. The immobilization of yeast in the an
nular passages of the hollow fibre prepared was also studied by SEM. The re
sults show that the yeast could successfully be immobilized in the cavities
of the inner layer and grew to very high densities throughout the annular
passages. (C) 2001 Elsevier Science B.V. All rights reserved.