Effect of TiO2 nanowire addition on PVDF ultrafiltration membrane performance

A new PVDF-TiO2 nanowire hybrid ultrafiltration membrane was prepared via phase inversion by dispersing TiO2 nanowires in PVDF casting solutions. The characteristics of the hybrid membranes, i.e., crystal structure, thermal stability, morphology, hydrophilicity, permeation performance, and mechanical properties, were investigated. Results of X-ray diffraction (XRD), thermal gravitational analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) analysis showed that the interaction existed between TiO2 nanowires and PVDF and the thermal stability of the hybrid membrane had been improved by the addition of TiO2 nanowires. Concurrently, dynamic contact angles indicated that the hydrophilicity of the hybrid membranes was enhanced by the addition of TiO2 nanowires. The effects of the TiO2 nanowires in the PVDF on the permeation properties, membrane strength, and antifouling performance were examined. The experimental results indicated that PVDF-TiO2 nanowire hybrid membranes exhibited significant differences in surface properties and intrinsic properties due to TiO2 nanowires addition. Most importantly, PVDF-TiO2 nanowire hybrid membrane can avoid some of the drawbacks of PVDF-TiO2 nanoparticle hybrid membrane, such as, aggregate and leak out of TiO2 nanoparticles, also declining elongation ratio.

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► Avoid aggregate and leak out of TiO2 nanoparticles.
► Improvement of elongation rate after adding the nanowire.
► Improvement of mechanical and thermal properties.
► The modified membrane had denser skins, as well as smoother surface.
► Enhanced both the permeability and antifouling performance.