Hydrophilic modification of polyvinylidene fluoride membrane by blending amphiphilic copolymer via thermally induced phase separation

A new amphiphilic copolymer TD-A is melt-blended with polyvinylidene fluoride to fabricate hollow fiber membranes in order to improve the hydrophilicity and anti-fouling property. Membrane samples with different blending ratios are prepared via thermally induced phase separation method. An optimum blending ratio of TD-A (10 wt%) is determined by a series of characterizations to evaluate the effects of TD-A contents on membrane properties. The hydrophilicity of the blended membrane samples increases with the increasing blending ratio, but excessive content of TD-A in blended membranes can lead to structural defects and reduction of mechanical properties. TD-A blended hollow fiber membrane with optimum blending ratio shows excellent bi-continuous structure and high water flux. Membrane fouling is remarkably reduced due to the incorporation of TD-A by static absorption and cyclic filtration tests of bovine serum albumin. Moreover, constant surface chemical compositions and stable flux during long-term chemical cleaning demonstrate the hydrophilic stability of the blended membrane.