However,
it was clearly found that the permeation water flux was so small
that there existed no applied prospect. Nunes [14] reported that
dense hydrophilic composite ultrafiltration membranes were prepared
by coating a thin layer of polyether-block-polyamide copolymer
on an asymmetric PVDF support. Membranes with molecular
weight cut off (MWCO) of 800–4500 and water permeability of
2.3–9.4 L/(m2 h bar) were obtained. The composite membranes
exhibited lower susceptibility to fouling. Bottino [15] studied sulfonated
polyvinylidene fluoride membranes systematically and
found that the modification process increased the hydrophilicity
and antifouling capability of the membranes. Munari [16] prepared
anisotropic sulfonated PVDF membranes, which exhibited excellent
antifouling ability against protein.