A series of pH-responsive gating membranes

with a wide range of grafting yields

were prepared by grafting poly(acrylic acid) (PAAC) onto porous polyvinylidene fluoride (PVDF) membrane substrates with a plasma-induced pore-filling polymerization method. The effect of grafting yields on gating characteristics of pH-responsive gating membranes was investigated systematically.The results showed that the grafting yield heavily affected water flux

pH-responsiveness coefficient and pH-responsive gating factor of membrane pore size. When the grafting yield was smaller than 1.01%

both flux responsiveness coefficient and pH-responsive gating factor of pore size increased with increasing grafting yield.When the grafting yield was in the range from 1.01% to 6.44%

both flux responsiveness coefficient and pH-responsive gating factor of pore size decreased with increasing grafting yield;however

when the grafting yield was higher than 6.44%

both flux responsiveness coefficient and pH-responsive gating factor of membrane pore size approached to 1

i.e.

little gating characteristics existed.In order to obtain a satisfactory pH-responsive gating property of the membrane

the grafting yield must be kept in a proper range.