Sequential Interpenetrating Polymer Network Confines Shear-Aligned Graphene Oxide Liquid Crystals Enabling Precise Molecular Sieving.

Graphene oxide (GO)-based membranes hold great promise for revolutionizing nanofiltration, thanks to their seamless water transport and efficient ion and molecular sieving capabilities. Yet, their practical application remains limited due to structural instability under high pressure and swelling of nanochannels caused by water intercalation. This work overcomes these issues by aligning GO-based liquid crystals via shear forces and stabilizing them with a sequential interpenetrating polymeric network (IPN) using electrostatic anchoring. The process preserves long-range order through nanoconfinement. Using dopamine and GO liquid crystals, a nematic phase is achieved at very low concentrations, unlike conventional approaches. Characterization via microscopy and spectroscopy confirms pore sizes of ∼7 nm due to nanomaterial inclusion. These highly ordered and structurally stable membranes demonstrate exceptional water flux (145 LMH) and >97% separation efficiency for monovalent/divalent salts, dyes, and antibiotics. Molecular dynamics (MD) simulations reveal reduced water flux upon confining rGO-I sheets in the IPN, scaling with rGO-I concentration, and show fewer ions within the membrane, supporting feed-side retention. These findings match experimental results. The membranes also display antifouling, chlorine resistance, antibacterial activity, and cytocompatibility. They remain stable over multiple uses and under harsh conditions, without swelling-demonstrating strong potential for large-scale, sustainable water treatment.