I am fabricating TFC membranes using interfacial polymerization with TMC and piperazine as monomers. I have tried different dipping for both monomer solutions, dipping and annealing duration. I have also tried different ways for removing excess water from the surface after dipping the polysulfone as the lower layer, in piperazine solution, however, with none, the polyamide layer becomes continuous. It rather forms as discrete islands. I appreciate suggestions in this regard.