Tailoring High-Performance Poly(<i>m</i>-phenylene isophthalamide) Ultrafiltration Membranes Using Green Amphiphilic Sugar Esters

This study pioneers the development of high-performance poly(<i>m</i>-phenylene isophthalamide) (PMIA) ultrafiltration membranes through synergistic integration of nonsolvent-induced phase separation (NIPS) and surface segregation techniques, employing sugar esters (SE-15) as an eco-friendly additive. Comprehensive characterization techniques were systematically conducted to investigate the influence of SE-15 on the microstructure, surface property and perm-selectivity of the SE-15/PMIA membranes. Specially, the nanoscale X-ray microscopy (Nano-CT) technique was employed to delve deeply into pore structures, revealing the effect of adding SE-15 on the evolution of pore channels. The synergistic interplay between SE-15's solubilization effect in the casting solution and its phase segregation behavior, as further verified through molecular dynamics simulations, significantly enhanced membrane porosity and hydrophilicity. With an appropriate SE-15 concentration (0.2 wt %), the SE-15/PMIA membrane demonstrated increased pore size (from 43.7 ± 3.0 to 62.2 ± 1.9 nm), porosity (from 67.0 ± 1.8 to 87.7 ± 2.2%), and hydrophilicity (from 69.6 ± 1.0 to 60.3 ± 1.3°) as well as a remarkable 32% improvement in pure water flux (from 576.0 ± 24.2 to 762.6 ± 5.4 kg·m^-2·h^-1) while maintaining bovine serum albumin (BSA) rejection rate >95%. As a green, nontoxic additive for advanced membrane engineering, SE-15 exhibits unique benefits in constructing porous PMIA membranes, offering a promising alternative to conventional petrochemical additives in polymer membrane fabrication. The SE-15/PMIA membranes demonstrate great potential in water treatment, particularly drinking water purification, municipal wastewater reclamation, and seawater pretreatment that require simultaneous high permeation and eco-safety.