A Novel Way to Modify PTFE Membrane into Hydrophilicity

Abstract

Polytetrafluoroethylene (PTFE) membrane, with high resistances to acid, alkali and other chemical corrosion, is the ideal filter material in water treatment, which can be used in a variety of harsh environment. However, the hydrophobictity of PTFE membrane limits its wide application in water treatment. Thus, the hydrophilic modification of PTFE membrane attracts much attention. In this work, the microporous PTFE membrane was treated by a novel strategy for enhancing its hydrophilicity. The pristine microporous PTFE membrane was modified by assembly of fluorocarbon surfactant. The structure and morphology of the membranes were characterized by attenuated Fourier Transform Infrared spectroscopy (ATR-FTIR) and scanning electron microscope (SEM). The variation of wettability was evaluated by the change of water contact angle (WCA). And the influences of the concentration of fluorocarbon surfactant and modification time on PTFE WCA were also investigated as well. The WCA of the pristine PTFE membrane is 156°. After modified by 5.0 g/L of fluorocarbon surfactants, the WCA reduced to 4.3°, indicating that the hydrophobic PTFE membrane was transformed into a hydrophilic one. FTIR and SEM results indicated that there were hydrophilic groups, such as carbonyl (-C=O) and hydroxyl (–OH) existing on the surface of PTFE membrane after modification. And WCA of the hydrophilic membrane showed a slight increase from 4.3°to 8° after a week, indicating that the hydrophilic PTFE membrane exhibiting a persistent durability.