A solution for trade-off phenomenon based on symmetric-like membrane with nano-scale pore structure

Outstanding separation properties combining high water permeability and permselectivity have always been a pursuit for porous membranes, which were commonly determined by the membrane structure and surface properties. In this work, PLA membrane with unique nanoscale bicontinuous structure was fabricated by non-solvent induced phase separation (NIPS) process involving in situ crosslinking of glycidyl methacrylate (GMA) monomers in polylactic acid (PLA) casting solution. Afterwards, systematic approaches were carried out to characterize the regulating functions of the in situ formed polymerized GMA (PGMA) on the morphology, pore shape, pore size, porosity, wettability , water flux and solutes rejection of developed PLA membranes. With the addition of GMA monomers, novel bicontinuous interconnected PLA membranes with narrowly distributed nanoscale pores were obtained. These generated PLA membranes presented higher water flux and better selective rejection to various dextran molecular owing to their larger effective pore size and narrower pore size distribution . This study provides an innovative strategy to overcome the trade-off issue when membranes are used for water treatment.