A method for making a composite polyamide membrane comprising the step of applying polyfunctional amine and acid halide monomers to a surface of a porous support and interfacially polymerizing the monomers to form a thin film polyamide layer. The method further includes the step of conducting the interfacial polymerization in the presence of: a carboxylic acid monomer comprising an aliphatic or aromatic moiety substituted with single carboxylic acid functional group and at least one acyl halide functional group, and a tri-hydrocarbyl compound.