Hierarchically engineered membrane surfaces with superior antifouling and self-cleaning properties

In nature, surfaces simultaneously possessing antifouling and self-cleaning properties allow living systems to sustain diverse functions. Integrating these features into synthetic surfaces will open a novel avenue to advanced surface-based or surface-governed technologies for medical, industrial, ocean, and environmental applications. In this study, we report in situ engineered porous membrane surfaces with hierarchical structure: the external membrane surfaces are covered with zwitterionic (hydrophilic) and low surface energy brushes, endowing the membranes with superior antifouling and self-cleaning abilities. The surface composition, hydrophilicity and surface energy are assessed for the valuation of the antifouling and self-cleaning potential of the membranes. When utilized for model wastewater treatment, the membrane fouling is exquisitely suppressed: permeation flux-decline is decreased to an ultralow level (less than 1%) and permeation flux recovery after simple hydraulic washing is retained at nearly 100%. The present method can be extended to the construction and modification of a broad range surfaces.