The effect of a N,N-dimethylformamide (DMF)/acetone solvent system (3:7, 4:6, 5:5, 6:4, 7:3) and spinning medium (air and water) on the membrane morphology and the structure-property relationship were investigated. A facile method was optimized to generate a porous, polymer-fiber membrane via the combinative effect of electrospinning and thermally inducing phase separation of the DMF/acetone (4:6) solvent system in a water medium. The attenuated total reflection (ATR) - Fourier transform infrared (FTIR) results showed an increased β-phase compared to the pristine poly(vinylidene fluoride) (PVDF). The XRD and DSC results further confirmed that the co-existing α- and β-phases in the pristine PVDF were converted into a unique β-phase in the electrospun membranes. In addition, the solvent uptake percentage of the DMF/acetone (4:6) solvent system in a water medium (540) is much greater than that in an air medium (320), and over two times better than that of commercial polyethylene (PE) membranes (190). Similarly, the discharge capacity of the PVDF membrane separator prepared with the DMF/acetone (4:6) solvent system in a water medium is higher than that of the air medium. This enhancement of solvent uptake might be due to the interconnected porous morphology present in the water medium.