Provided is an interfacial polymerization process for preparation of a highly permeable thin film composite membrane, which can be used for nanofiltration, or forward or reverse osmosis, for use with tap water, seawater and brackish water, particularly for use with brackish water at low energy conditions. The process includes contacting a porous support membrane with an aqueous phase containing a polyamine and a flux enhancing combination, which includes a metal chelate additive containing a bidentate ligand and a metal atom or metal ion and a dialkyl sulfoxide, to form a coated support membrane, and applying an organic phase containing a polyfunctional acid halide to the coated support membrane to interfacially polymerize the polyamine and the polyfunctional acid halide to form a discrimination layer of the thin film composite membrane. Also provided are the membranes prepared by the methods and reverse osmosis modules containing the membranes.