Hydrophilic ultrafiltration membranes with surface-bound eosin Y for an integrated synthesis-separation system of aqueous RAFT photopolymerization

Abstract

Aqueous photoinduced electron/energy transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization can achieve both precision and environmental benignity observed in nature; however, the cumbersome product purification via dialysis substantially reduces the production efficiency. The industrialized membrane technology has enlightened a scalable and inexpensive strategy for the surface tethering of a photocatalyst onto the membrane materials to fabricate the photocatalyst-loaded composite membranes. These composite membranes are capable of toggling PET-RAFT polymerization in an integrated synthesis-separation system to simplify the production process and narrow the gap between precision and efficiency. Herein, the eosin Y-based copolymers were attached to the polydopamine pretreated commercial UP005 ultrafiltration membranes to produce the hydrophilic composite membranes with excellent catalytic performance. Moreover, these composite membranes conferred radical polymerizations with varied desirable traits such as the adaptability of numerous chemical diversity, unique oxygen tolerance, and superior control over the monomer formulations. The composite membrane allowed more than 95% removal of the residual reactants and achieved a high polymerization efficiency demonstrated by the 94% monomer conversion. The separation and reutilization of the catalyst-modified composite membranes were achieved through extracting with ultrapure water, affording inappreciable catalyst leakage, and sustainable catalytic activity over several polymerization runs. By virtue of the robustness of the composite membranes, the organocatalysts were supported in an integrated synthesis-separation system to produce well-structured polymers via a batch-wise process.