Interfacial hydrogen bonding and phase-inversion kinetics drive 3D pore networks in PLA–CNF membranes for dialysis-grade selectivity

Abstract

Bio-based dialysis membranes could reduce polymer waste and additive leaching risks associated with conventional petroleum-derived dialyzers, but most bio-based systems have not been validated for dialysis permselectivity ( i.e., high passage of uremic toxins with protein retention) nor linked mechanistically to structure formation. Here, we report fully biobased poly(lactic acid)–cellulose nanofiber (PLA–CNF) composite membranes fabricated via scalable casting–phase inversion. CNF loading increased porosity from 58.5% to 75.7% and decreased water contact angle from 116° to 65°, enabling a ∼ 3 × higher water flux from 53.4 to 166.4 L m⁻²h⁻¹ at 0.5 ± 0.025 bar. In dialysis-mimicking separations, the membranes exhibited remarkably high solute passage, i.e., urea clearance ˃94% and creatinine clearance ˃ 85, with albumin rejection up to 78%. In addition, both pristine and composite membranes were cytocompatible (>85% viability for L929 and Vero cells). These results position PLA–CNF membranes as a sustainable platform for dialyzers and liquid purification modules, with future optimization targeting antifouling/charge-selective interfaces and long-term hemocompatibility under realistic flow regimes.