Construction of self-healing polyethersulfone ultrafiltration membrane by cucurbit[8]uril hydrogel via RTIPS method and host-guest chemistry

In this work, the self-healing polyethersulfone ultrafiltration membrane constructed by host-guest chemistry be-tween cucurbit [8]uril (CB [8] is a family of macrocyclic compounds comprising 8 glycoluril units) and two guest molecules based on reverse thermally induced phase separation (RTIPS) method was developed, which had excellent self-healing performance, better mechanical properties, and high permeation flux and BSA rejection rate. The membrane autonomously restored it BSA rejection rate up to about 89% from rejection rate levels as low as 21% after damage. The observed self-healing performance were attributed to the swelling of pore-filled CB [8] hydrogel into the damage position, the molecular interdiffusion of the hydrogel chains, the strong hydrogen bond of the hydrogel chains and the host-guest interaction between CB [8] and two guest molecules (HEC-Np and PVA-MV). SEM morphologies illustrated that the prepared pore-filled membrane via the RTIPS method had homogeneous and porous skin surface and sponge-like cross-section, which imparted the prepared membranes with improved permeability and better mechanical properties. Properties of MR-CB [8] membranes, which varied with increased content of CB [8], were evaluated by permeability, water contact angle, thermogravimetric analysis (TGA), me-chanical properties, FRR, scanning electron microscope (SEM) and atomic force microscopy (AFM). The contact angle water showed that CB [8] hydrogel enhanced the surface hydrophilicity of the prepared membrane. TGA illustrated that the thermal stability improved with the increased content of CB [8]. The optimal pore-filled CB [8] hydrogel membrane (MR-CB [8]2) exhibited that the pure water flux reached 2100.5 L/m2 h, while the BSA rejection rate remained at 86.0%. The results of this work suggested pore-filled CB [8] hydrogel membrane was a more promising way to develop polyethersulfone ultrafiltration membranes with self-healing performance.

Automated summary

In this study, a self-healing polyethersulfone ultrafiltration membrane was developed using host-guest chemistry and reverse thermally induced phase separation method. The membrane showed excellent self-healing performance, better mechanical properties, high permeation flux, and BSA rejection rate. The self-healing was attributed to the swelling of CB [8] hydrogel, molecular interdiffusion, and host-guest interaction. The prepared membrane had a homogeneous and porous structure, improving permeability and mechanical properties. Evaluation of the membrane properties showed enhanced surface hydrophilicity and thermal stability with increased CB [8] content. The optimal membrane exhibited a pure water flux of 2100.5 L/m2 h and a BSA rejection rate of 86.0%. This work suggests that pore-filled CB [8] hydrogel membrane is a promising approach for developing self-healing polyethersulfone ultrafiltration membranes.