Abstract: Acetylene tributyl citrate (ATBC) and triethyl citrate (TEC) were taken as ecologically friendly hydrophobic diluents to partially replace dimethyl formamide (DMF) and then used as a mixed solvent to fabricate poly(vinylidene fluoride) (PVDF) membrane through supercritical CO2-induced phase separation.The morphologies and structures of the prepared PVDF membranes were influenced significantly with the addition of ATBC or TEC.The membrane surface and cross section were found to become much rougher especially when the amount of ATBC or TEC was increased to 50 wt %.Such a phenomenon is quite different from the membrane prepared with pure DMF.Contact angel measurement proved that the hydrophobicity of the membrane was associated with the surface roughness.The thermodynamic properties of the membrane were not affected by the amounts of ATBC or TEC used for preparation.However, there was a crystal transformoccurred when the amount of ATBC or TEC reached 50 wt %, which resulted in the formation of more β-form crystals.