Harnessing Macromolecular Crowding of Proteins for Engineering Sustainable Nanofiltration Membranes

ABSTRACT Membrane technology using advanced materials paves the way towards slashing industrial energy consumption. Protein‐based separation membranes were engineered through macromolecular crowding of proteins induced by interactions with various green solvents to fabricate biodegradable, solvent‐resistant nanofiltration membranes. Single‐molecule tracking using quantum dots provided unprecedented insights into the real‐time dynamics of membrane formation at the microscopic level. Molecular dynamics simulations corroborated these findings, highlighting the roles of macromolecular crowding and chain entanglement. The structural characteristics of the membranes by means of small‐ and wide‐angle X‐ray scattering spectroscopies were uncovered. The interpolymer chain distance, polymer conformation, and polymer chain arrangement were considerably influenced by interactions with different solvents. These structural modifications resulted in distinct membrane morphologies and mechanical properties. The biodegradable membranes exhibited excellent solvent resistance and molecular sieving performance in the nanofiltration range under high‐pressure conditions. A case study demonstrated the successful removal of a carcinogenic impurity from a pharmaceutical. Given the abundance of proteins in biomass, our findings open the door for the development of sustainable and robust membranes through the manipulation of proteins.