Sequential interfacial polymerization of polyester thin-film composite membranes on solvent-resistant cellulose supports for tunable organic solvent nanofiltration

초록

Thin-film composite (TFC) membranes for organic solvent nanofiltration (OSN) require precise control over molecular selectivity and robust resistance to solvent-induced degradation. Unlike single-step interfacial polymerization, which offers limited control over network development, sequential interfacial polymerization (SIP) enables stepwise densification of ester-linked selective layers and thereby provides a practical route to tune molecular weight cut-off (MWCO) and solvent permeance. Here, we report a straightforward SIP strategy for fabricating highly crosslinked polyester (PE) TFC membranes with tailorable molecular selectivity. Regenerated cellulose (RC) was used as a mechanically robust and solvent-resistant support, and the PE selective layer was formed by sequential interfacial reactions of trimesoyl chloride (TMC) with 3,5-dihydroxybenzoic acid (DHBA), followed by isophthaloyl chloride (IPC) end-capping. Progressive IP cycles increased ester-linkage formation and refined the polyester network, resulting in a controlled decrease in apparent MWCO and systematic modulation of solvent permeance. This SIP approach provides a versatile platform for designing OSN membranes with tunable separation characteristics and stable performance in organic solvents.

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