Hollow fiber spinning of dual-layer membranes

Dual-layer hollow fiber membranes, due to their significant advantages in material cost and structural design, have become increasingly attractive. However, one must conduct much more complex experiments including many spinning parameters than those conventional single-layer hollow fiber membranes in order to obtain a regular cross-section morphology and good adhesion between the two layers for long-term performance stability. Therefore this chapter not only introduces the mechanisms behind the delamination phenomenon, irregular morphology, and substructure resistance, but also summarizes the effects of various operating conditions in the spinning process which would help find the optimal parameters. Moreover, the existing applications of dual-layer hollow fiber membranes based on the state-of-the-art literature research are described.