High water permeating thin film composite polyamide nanofiltration membranes showing thermal responsive gating properties

High water permeating thin film composite (TFC) polyamide (PA) nanofiltration (NF) membranes were prepared by grafting 2-(Dimethylamino)ethyl methacrylate (DMAEMA) monomers onto their surfaces through a free radical polymerization process. Grafted PDMAEMA layer increased the water permeation of TFC-PA NF membranes up to 2.6 times without trading off their salt rejection capability. The anti-fouling performance of the NF membranes was improved by further surface zwitterionization processes involving 1,3-propane sulfone(1,3-PS). Thermal-responsive gating property for water and salt permeation was observed in these high flux NF membranes and found to be useful in trapping and releasing protein molecules via temperature variations. These high flux NF membranes with thermal-responsive gating property may find applications in material enrichment, drug delivery and water treatments.