A series of thermo-responsive gating membranes

with a wide range of grafting yields

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

responsiveness coefficient and thermo-responsive gating factor of membrane pore size. When the grafting yield was smaller than 2.81%

both responsiveness coefficient and thermo-responsive gating factor of pore size increased with increasing grafting yield; however

when the grafting yield was higher than 6.38%

both responsiveness coefficient and thermo-responsive gating factor of membrane pore size were always equal to 1

i.e.

no gating characteristics existed. In order to obtain a satisfactory gating property of the membrane

the grafting yield must be kept in a proper range.