Toward Microcapsule-Embedded Self-Healing Membranes

We herein report the first instance of a self-healing water treatment membrane that restores its water flux and particle rejection properties autonomously. The self-healing membrane is fabricated by embedding microcapsules with a polyurethane shell and an isophorone diisocyanate core within a conventional poly(ether sulfone) membrane. A dual-surfactant system and polydopamine coating were used to control the size of these microcapsules and avoid capsule buckling. When the membrane structure is physically damaged, the microcapsules release a reactive isocyanate healing agent that reacts with the surrounding water to form a polyurea matrix that plugs the damage. The self-healing was found to recover the water flux and particle rejection of the membrane to 103 and 90% of the original membrane's performance, respectively. The results of this study show that microcapsule-embedded membranes are a promising approach to fabricating versatile, next-generation membranes that can self-heal.