The invention relates to polymeric ultrafiltration or microfiltration
membranes of, for instance, Halar, PVDF or PP, incorporating PVME or
vinyl methyl ether monomers. The PVME may be present as a coating on the
membrane or dispersed throughout the membrane or both. The membranes are
preferably hydrophilic with a highly asymmetric structure with a reduced
pore size and/or absence of macrovoids as a result of the addition of
PVME. The PVME maybe cross-linked. The invention also relates to methods
of hydrophilising membranes and/or preparing hydrophilic membranes via
thermal or diffusion induced phase separation processed.