Fabrication of a superhydrophobic poly(vinylidene fluoride) hollow fibre membrane by spray deposition

In this work, a poly(vinylidene fluoride) (PVDF) hollow fibre membrane for liquid-gas membrane contactor was coated with a superhydrophobic layer comprising a combination of hydrophobic SiO₂ nanoparticles and polydimethylsiloxane. A rough layer of SiO₂ deposited on the PVDF membrane resulted in an enhanced surface hydrophobicity. The surface structure of the pristine PVDF significantly affected the homogeneity of the generated SiO₂ layer. A uniform surface coating on the PVDF upper layer resulted from the presence of micrometre and nanometre sized roughnesses on the surface of the PVDF membrane, which was achieved with a SiO₂ concentration of 4.44 mg ml^-1 (0.2 g/45 ml) in the coating solution. As a result, the water contact angle of the modified surface was recorded as 155 ± 3°, which is higher than that of the pristine surface.