Ionic liquid1-(n-Octyl)-3-Methyl limidazolium hexfluorophosphate ［C8mim］［PF6］ was used as a structurecontrolling additive

and polysulfone (PSF) membranes with different structures were prepared by the wetphaseinversion in this work.The results indicated that ionic liquid ［C8mim］［PF6］ had important influence on the poreforming.With increase of concentration of ionic liquid ［C8mim］［PF6］ in casting solutions

the structures of the membranes changed from asymmetric finger pore

the lengthenedbig pore and the big caves to spongy pore.When the concentration of ［C8mim］［PF6］ was 4%

the membrane had the asymmetric fingerpores structure

the pore size close to its surface layer was about 2~6 m and that close to its sublayer was about 10~70 m

the retention rate and flux of PEG10000 were 92.3% and 33.7 L #12539; h-1 m-2.The analysis indicated that hydrophobic ionic liquid ［C8mim］ ［PF6］ could improve orderly arrangement of polysulfone molecules at the low concertration

while the strong delay of phase inversion appeared at the high concertration.It was found by X-ray EDS analysis of PSF membranes with SEM

ionic liquid ［C8mim］［PF6］ was partially retained in the prepared polysulfone membrane.This reduced the contact angles between water and polysulfone membranes

improving the hydrophilic properties of the membranes.Meanwhile

the formation mechanism of pore structures in the membrane preparation was also discussed

［C8mim］［PF6］ could restrain demixing of the casting solutions as a poreforming agent and plasticizer.