(658c) Self-Healing and Non-Swellable Polymer for Water Filtration Membrane

Damage to water filtration membranes during installation and operation can significantly degrade the quality of the product water. Membranes with self-healing capabilities could autonomously restore their original rejection levels, thus negating the need for costly integrity monitoring and membrane replacement practices. However, most existing self-healing polymers suffer from swelling-induced mechanical instability and a loss of self-healing ability due to substantial water uptake when fully submerged. Therefore, a carefully considered design principle is crucial to prevent the swelling-induced deterioration of self-healing polymers for long-term use in water-related applications. In this study, we present a polymer that exhibits high self-healing ability and low swelling (i.e., < 3 wt% of swelling) when submerged in water. The dynamic crosslinking of catechol-functionalized polymers with p-phenyldiboronic acid (PDBA) via non-ionic boronate ester bonds is pivotal in achieving these two properties simultaneously. The non-ionic boronate ester crosslinkers are dispersed within a hydrophobic catechol polymer matrix, enabling materials to self-heal with high water stability. We introduced this polymer into an ultrafiltration membrane using a straightforward interfacial polymerization method. To evaluate the self-healing efficiency of the membrane, we assessed changes in water flux at three stages: pre-damaged, post-damaged, and post-healing. The results revealed a high water flux and remarkable self-healing efficiency of up to approximately 95%. This study demonstrates that a membrane coated with a self-healable and non-swellable polymer represents a promising new class of materials for fabricating self-healing membranes.