Commercial polysulfone membrane with negative surface charge was modified by low temperature plasma to initiate graft polymerization of 2-[DK](dimethylamino)ethyl methacrylate (DMAEMA)

introducing positive charge onto HT membrane surface.It was confirmed by the XPS results that the introducing of positive charge group.Surface charge of the membrane was determined by measuring electroosmotic flux across the membrane.The effects of operation parameters including treatment power

treatment time

and polymerization time on the modification process were examined.The results also showed that surface modification by low temperature plasma

as described in the present paper

effectively reduced the net negative charge of membrane surface

and moreover

the adsorption of lysozyme on the membrane surface.