A novel hydrophilic modification method for polytetrafluoroethylene (PTFE) hollow fiber membrane using sacrificial template

In order to enhance the hydrophilicity of PTFE hollow fiber membrane, high concentration of polymer was needed during the modifying process, but this method resulted in severe pore blockage of hollow fiber membrane with reduced water flux. Herein, we resolve the above contradiction by using cross-linkable poly (vinylpyrrolidone-co-γ-methacryloxypropyltrimethoxysilane) (P (VP-co-KH570)) as hydrophilic polymer and calcium chloride as sacrificial template. The enhanced hydrophilicity and chemical washing resistance of PTFE hollow fiber membrane were achieved by the highly hydrophilic PVP segments and highly crosslinking density contributed by hydrolysis and condensation of the KH570 segments, respectively. The template is embedded in the polymer network formed in the membrane pores, and after template removal the previously occupied pores are released for water transport, thereby minimizing the loss of water flux. The high water flux (1477.14 ± 16.11 L/(m2·h)), superhydrophilicity (the water contact angle = 0°) and hydrophilic stability proved that PTFE hollow fiber membranes are successfully modified by the sacrificial template method. This work provides a facile strategy for designing hydrophilic PTFE hollow fiber membranes for water treatment.