How does Micro‐ and Macro‐Phase Separation of Block Copolymers Affect the Formation of Integral Asymmetric Isoporous Membranes? A Review on Effective Factors

Abstract

AbstractSelf‐standing isoporous membranes based on amphiphilic block copolymers (BCPs) are an outstanding candidate for efficient separation processes. Such fascinating membranes have been generated through combining the BCP self‐assembly (micro‐phase separation) together with the classical non‐solvent induced phase separation (macro‐phase separation), known as SNIPS process. However, the controllability, reproducibility, and cost‐effectiveness of the process along with the mechanism for pores generation are still challenging in the SNIPS strategy, especially when new BCP or conditions are utilized. It is mainly due to the narrow efficacy window of numerous variables influencing the desired structure formation. In this review, first, an overview of the one‐step readily scalable SNIPS technique and the stepwise explanation of the process are given. Then the formation mechanism of SNIPS membranes, according to the related hypotheses and assumptions proposed on the basis of experimental evidence so far, is presented and discussed. As the main focus , governing factors in the SNIPS process which affect the preparation and structural characteristics of final membrane structures are entirely reviewed and interpreted. This review will help to have a better understanding of the connection between determinant factors and final membrane structure, which facilitates successful preparation of BCP membranes via SNIPS.