Study on the modification of polyvinylidene fluoride with polyurethane to achieve excellent hydrophilic property

Polyvinylidene fluoride (PVDF) is a promising membrane material in ultrafiltration (UF) applications; its extensive application however is limited due to the disadvantage in hydrophilicity and low surface energy. Herein, a sort of TPU-modified PVDF membrane is prepared by blending method and its hydrophilicity is compared with a series of pure/modified PVDF membranes. The contact angle and pure water flux (PWF) results demonstrate that the hydrophilicity of the TPU-modified PVDF membrane is enhanced, and the performance is not inferior to that of traditional pore-modified PVDF membranes. SEM image shows that the TPU-modified PVDF membrane maintains morphology of the pure PVDF membrane, indicating that TPU molecules have excellent compatibility with PVDF molecules and can maintain the mechanical property of PVDF membrane to a certain extent. Finally, we explore the effects of TPU molecules and PVDF molecules on water molecules, respectively, from a microscopic perspective involving first principles. This investigation not only establishes that PVDF membrane has been prepared with enhanced hydrophilicity, but also provides a novel avenue for the modification of membrane properties.