Self-healing polymeric materials for membrane separation: an example of a polybenzimidazole-based membrane for pervaporation dehydration on isopropanol aqueous solution

Abstract

This study proposes a self-healing membrane for pervaporation separation, with a focus on in situ repairing damaged membranes within the separation module. The self-healing membrane is fabricated with a thermally-reversible crosslinked polybenzimidazole (PBI) based on a newly prepared furan-functionalized PBI (PBI-FA) and a commercially-available bismaleimide (BMI) as raw materials. The thermally reversible crosslinked property and self-healing ability of the PBI-FA/BMI membrane have been evaluated using morphological and mechanical tests. The membrane demonstrates a high separation efficiency level (water concentration on the permeate side (C_water > 99.99 wt%)) and moderate permeation flux (117 ± 11 g m⁻² h⁻¹) for pervaporation dehydration with a 70 wt% isopropanol aqueous solution. Membrane damage caused by a knife incision engenders a loss of separation function. However, recovery of the separation function with a C_water of approximately 94.27 ± 0.14 wt% (self-healing efficiency: 94%) is achievable when the membrane was subjected to the self-healing process. Results from a 50 day long-term stability test indicate that self-healing efficiency could reach 97%, with a recovered C_water of approximately 96.83 ± 0.24 wt%. The self-healing process can prolong membrane life and reduce cost, effort, and wasted resources associated with total membrane replacement.