Polypropylene Glycol: The Hydrophilic Phenomena in the Modification of Polyethersulfone Membranes

In this work, the polypropylene glycol (PPG) was observed showing obvious hydrophilicity improvement to polyethersulfone (PES) membranes when it was introduced. The water contact angles of the blend membranes were significantly lowered to 50 degrees when contents of PPG were 25 wt % in the as-formed membranes. The stability test presented a good durability of PPG when blend membranes suffered a 70 days water washing. Surface constitution analysis revealed that PPG concentration in the near surface was nearly two times higher than the theoretic value, indicating the surface enrichment of PPG in membranes. A pore-forming effect was also observed though the porosity increase was not obvious. The results of platelet adhesion, flux recovery, and protein adsorption indicated a nice fouling-resistance property of blend membranes. The molecular folding as well as the surface aggregation of PPG was explored as a reason for the hydrophilic improvement to blend membranes.