Critical contributions of additive directed fabrication of isoporous membranes via the self-assembly and non-solvent induced phase separation: A review

Abstract Isoporous membranes have attracted increasing attention for their critical applications on precise and fast separation. The breakthrough was made recently on scalable fabrication by combining the block copolymer self-assembly (S) with non-solvent induced phase inversion (NIPS), which is known for its excellent compatibility with roll-to-roll production. Namely, isoporous membranes can be largely prepared and their scalable application is on the way. However, much effort is still needed to improve the structural reproducibility, control the defects, cut the cost and solve general problems such as fouling, durability, and trade-off effect which are commonly found for porous membranes. The blending with additives is a flexible and effective way extensively adopted by the SNIPS to solve these problems. Metal salts, small organics (acids, polyols, etc.), polymers, and nanomaterials (graphene oxide, nanoparticles, etc.) had been successfully doped to isoporous membranes to tailor the isopores formation, increase the permeability, cut polymer consumption, reduce the fouling, improve the structural reproducibility, and so on. The functions of additives on directed isoporous membrane fabrication cover a broad range and keep expanding. In this review paper, the contributions and mechanisms of additive on solving the aforementioned challenges are systematically presented from an interdisciplinary perspective of NIPS and directed block copolymer self-assembly. Summaries of progress on this specific area will shed light on the function-led utilization of additives which are expected to pave the ways for an easier fabrication as well as the real application of isoporous membranes in the future. A brief outlook is given at the end of this paper.