Incorporation of barium titanate nanoparticles in piezoelectric PVDF membrane

The micro-vibration of piezoelectric polyvinylidene fluoride (PVDF) membranes has been shown to mitigate fouling. To improve the desired piezoelectric properties, piezoelectric barium titanate (BaTiO₃) nanoparticles (NPs) were incorporated into PVDF membranes fabricated by non-solvent induced phase separation (NIPS). Due to the high surface energy of BaTiO₃ NPs, the nanoparticles tended to agglomerate and were not dispersed uniformly. The silane coupling agent (3-Aminopropyl)triethoxysilane (APTES) with the BaTiO₃ NPs showed enhanced compatibility and dispersion in the PVDF membrane. The resulting BaTiO₃-PVDF membranes had similar finger-like pore structure as neat PVDF membrane. The dielectric strength, piezoelectric and mechanical properties of BaTiO₃-PVDF membranes were enhanced. A linear correlation (R² = 0.9391) between piezoelectric d₃₃ coefficient and critical flux was observed for poled BaTiO₃-PVDF membranes under the influence of electrical AC signal (10 Vpp, 500 Hz) when colloidal silica was used as model foulant. The optimal BaTiO₃-PVDF membrane (0.1 wt% BaTiO₃, poled and AC applied) showed up to 51% increase in critical flux compared to the neat PVDF membrane (unpoled and no AC applied). Further, extended durations of multiple filtration cycles by up to a factor of 2 to 4 were observed. The membrane operation could be prolonged due to significant reduction in irreversible fouling.