Seawater desalination materials have made enormous progress, polymer membranes widely used in Direct Contact Membrane Distillation processes for the treatment of seawater (Brine). In this study, membranes containing ionic liquids (ILs) were employed to improve diffusion of fresh water during the treatment processes. Prepared membranes were characterized by different spectroscopic techniques. Influences of several factors were examined, in order to improve performances, explain results and elucidate the diffusion mechanism of water molecules through the membrane. Specific parameters, flux F, permeability P, apparent diffusion coefficient D* and activation parameters (Ea, ΔH≠ and ΔS≠) were quantified. The analysis of results indicated a better performance for the membrane based on ionic liquid (F = 4.76 × 10–6 mol/cm2.s, P = 0.43 cm/s, D* = 2.14 × 10–3 cm2/s, Ea = 14.45 kJ/mol, ΔH≠ = 11.95 kJ/mol and ΔS≠ = -318.99 J/K.mol) compared to its counterpart PVFD polymer support (F = 4.47 × 10–7 mol/cm2.s, P = 0.04 cm/s, D* = 2.02 × 10–4 cm2/s, Ea = 21.59 kJ/mol, ΔH≠ = 19.09 kJ/mol and ΔS≠ = -315.29 J/K.mol).Results indicated a diffusion mechanism by tridentate association of water molecule with the interaction site of IL in the membrane phase.