Highly Permeable Polyamide Membranes Based on Hexafluoroisopropylidene Molecular Scaffold for Efficient Organic Solvent Nanofiltration

ABSTRACT Developing highly permeable polyamide (PA) thin‐film composite (TFC) membranes is a critical pathway for advancing organic solvent nanofiltration (OSN) in industrial chemical separations. Herein, we reported a dual‐regulation strategy utilizing a molecular scaffold to construct PA TFC membrane with enhanced solvent permeance. Acting as a “molecular scaffold”, the –C(CF 3 ) 2 – group of the 2,2‐bis (4‐aminophenyl) hexafluoropropane (BAFP) effectively modulates the packing behavior of PA chains through steric hindrance. Simultaneously, the fluorinated moieties reduce transport resistance by weakening solvent‐membrane interactions. The prepared TFC‐BAFP membrane exhibited an excellent methanol permeance of 20.3 L m −2 h −1 bar −1 , a 3.4‐fold increase over conventional TFC membrane prepared with 4,4'‐diaminodiphenylmethane (MDA). Furthermore, the enhanced rigidity of the BAFP monomer imparted great structural stability and solvent resistance, even under harsh chemical conditions. The TFC‐BAFP membrane also demonstrated efficient sieving for photosensitizer/precursor mixture system and exhibited significantly higher concentration efficiency than the commercial oNF‐2 OSN membrane. This work proposes a molecular engineering strategy for developing highly permeable polyamide OSN membranes by regulating monomer steric hindrance and surface properties, contributing to the advancement of sustainable separation technologies in the chemical and pharmaceutical industries.