Strategic small molecule engineering: Unleashing the full potential of Kevlar aramid membrane in organic solvent nanofiltration

Kevlar aramid fiber (KANF), renowned for its exceptional solvent resistance, holds immense potential in fabricating of solvent-resistant membranes. However, the well-ordered structure of its rigid polymeric chains, coupled with intense intermolecular forces, significantly impedes the transport of solvents. Here, we propose a methodology utilizing small molecule polyethylene glycol (PEG) to mediate an interlayer structural reconstruction of KANF membranes, thereby enhancing solvent permeation. PEG, functioning as a nanostructure regulator, effectively inhibits the diffusion of DMSO into non-solvents during the phase inversion process. This intervention results in the multi-directional polymerization of aramid nanofibers and the emergence of distinctive interconnected microporous structures between layers, which notably accelerates the transport speed of solvents within the membrane. Concurrently, preserving of the dense layer on the surface ensures superior separation performance for the KANF membranes. This research underscores the possibility of modulating the internal microstructure of KANF membranes and highlights the prospective utility of KANF-PEG membranes in the organic solvent nanofiltration field.