Fabrication of self-repairing and low-swelling polymer network via dynamic boronic ester bonds for enhanced membranes longevity and stability

Membrane technology has become a promising solution for a wide range of separation processes, including wastewater treatment, solvent recovery, and oil–water separation, due to its low energy consumption, cost-effectiveness, and minimal space needs. However, membrane damage caused by suspended pollutants or improper handling remains a challenge, often leading to decreased filtration capability and the need for replacement of membrane modules. Self-repairing membranes have emerged as a new solution, with various materials demonstrating autonomous healing properties through dynamic bonds such as hydrogen bonds or boronic ester bonds. However, many of these self-repairing membranes suffer from excessive swelling in water, compromising their mechanical stability. Herein, we report a self-repairing and low-swelling polymer network based on dopamine acrylamide (DA) and n-butyl acrylate (BA), crosslinked with p-phenylenediboronic acid (PDBA). The boronic ester bond formation between catechol and boronic acid groups confers self-healing properties to the polymer, while the hydrophobic nature of BA minimizes swelling in water. The polymer exhibits a low swelling ratio of 2.1% after 7 days of submersion in water. A cellulose-based filter paper coated with the polymer demonstrated that it can recover its water flux up to 91% after repairing damage. Lastly, an ultrafiltration polyethersulfone (PES)-based filter coated with the polymer demonstrated that it recovers its solute rejection capability after repairing damage.