Nanofiltration membranes occupy a crucial position in membrane technology due to their superiority of high separation efficiency and low energy cost, which are therefore widely applied in the field of water treatment, food and medicine, membrane bioreactor and petro chemistry. Most nanofiltration membranes are made from polymeric materials with composite structure containing a thin selective layer and a porous support layer. As the key of this structure, the selective layer can be fabricated via various met...