Rheologically controlled design of nature-inspired superhydrophobic and self-cleaning membranes for clean water production

This work presents a novel spray-assisted nonsolvent induced phase separation (SANIPS) approach for fabricating self-cleaning polyvinylidene fluoride (PVDF) membranes with superhydrophobic properties. The membranes exhibit high porosity and hierarchical micro/nanostructures, resulting in water contact angles of 151.9–156.2° and sliding angles of 9.6–22.6°. The spraying step creates surface distortion and a two-stage phase inversion, leading to multilevel polymeric crystal structures. Membrane properties are tunable by varying spraying materials. Superior anti-wetting and self-cleaning were demonstrated via direct contact membrane distillation (DCMD) tests using hypersaline wastewater. The SANIPS membrane maintained a stable vapor flux of 36.0 kg m⁻² h⁻¹ at 60 °C and >99.9% salt rejection over 100 h. This green fabrication method shows promise for large-scale production of superhydrophobic and self-cleaning membranes.

Kang Jia Lu, Dieling Zhao, Yuanmiaoliang Chen, Jian Chang, Tai-Shung Chung