Coral-tentacle-inspired antifouling membrane spacer: A natural solution for biofouling prevention

Fouling of membrane spacers leads to increased pressure drop and reduced lifespan of membrane modules. Cleaning these fouled spacers is challenging due to strong foulant-membrane spacer interactions. To address this issue, we introduce a novel spacer, PP-N-F, inspired by coral's antifouling properties. This spacer features on-demand antifouling capabilities through a sequential growth process of functional polymer brushes on its surface. It not only possesses lower surface free energy characteristics than polypropylene spacers, but also exhibits controllable morphological changes similar to swaying coral tentacles. Temperature control strengthens the interfacial hydration layer, mitigating the trade-off between anti-adsorption and hydrophobicity of fluorinated surface. The temperature-responsive surface changes enhance foulant desorption efficiency. Compared to a commercial spacer, PP-N-F shows an 89.3% reduction in foulant adsorption and a 61.7% decrease in pressure drop increment after 48 h cross-flow filtration experiments. This work provides valuable insights for advanced anti-fouling membrane module design.