The phase inversion procedure was used to prepare flat sheet membranes from polyvinylidene fluoride, PVDF. The impacts of casting solution composition, and exposure time on coagulation, were studied. For vacuum membrane distillation (VMD) of seawater desalination, PVDF flat sheet membranes with a novel sandwich structure and excellent wet resistance have been developed. The performance of the membrane was evaluated using an aqueous NaCl solution. At a temperature of 60°C for the feed and 16°C for permeate, a permeate flux of up to 21.24 lit/m2h were achieved. A salt rejection rate of more than 96 % was obtained in permeate. The water droplet had a contact angle with the membrane surface of 93°. CNTs were added as a hydrophilic agent to improve the membrane flux. PVDF membranes coated with carbon nanotubes are used in membrane distillation to provide superhydrophobic surfaces. These membranes showed high flux and excellent salt rejection, indicating will be used in desalination applications. Pore wetting, which has a negative effect on salt rejection, was improved, and the membrane stability was improved with these modified membranes. The membrane modified with CNT/ODA had the maximum water flux (23 lit/m2.h) and high salt rejection (up to 98%). The water contact angle (WCA) of the coated membrane is (108.4°). Scanning electron microscopy is used to examine all membrane structures. The porosity of the membranes ranged from 60 to 86 %.