The present invention provides a composite membrane comprising a porous base membrane and a polyamide coating disposed on said porous base membrane, said polyamide coating comprising a C3-C8 cyclic carbonyl compound and a C1-C8 amide compound, said amide compound comprising at least one N—H moiety. In addition the present invention provides a method of preparing a composite membrane comprising contacting under interfacial polymerization conditions an organic solution comprising a polyacid halide with an aqueous solution comprising a polyamine, said contacting being carried out on a surface of a porous base membrane, said organic solution further comprising a C3-C8 cyclic carbonyl compound, said aqueous solution comprising a C1-C8 amide compound, said amide compound comprising at least one N—H moiety.