Tailoring the structure and performance of polyamide membranes by modulating the reactant concentration during interfacial polymerization

Tailoring the structure of polyamide thin film composite (TFC) reverse osmosis (RO) membranes prepared via interfacial polymerization (IP) remains a formidable challenge due to the intrinsically rapid nature of polycondensation reaction, impeding the further enhancement of membrane separation performance. In this work, a new strategy for polyamide structural manipulation is proposed, wherein the reaction-zone amine concentration is finely modulated thanks to the surface chemistry reconstructed substrate (SCRS). Distinct SCRSs, characterized by their exquisitely engineered surface chemical environments, spans a broad spectrum of the interaction force with amine monomers, enabling the on-demand control over the reaction-zone amine concentration. Such modulated reactant concentration tunes the H + and heat production and thus the nanobubble generation during IP process, thereby facilitating to form homogeneous polyamide selective layers with tailorable surface morphologies based on the established correlation between reaction-zone amine concentration and polyamide surface morphologies, contributing to the impressive improvement in separation performance (a 2.1-fold flux enhancement alongside competitive NaCl rejection) and anti-fouling propensity (a flux recovery ratio of 99.4%). Our current strategy demonstrated the capability for continuous tuning of the proportion of surface structural constituents across an extensive range by engineering the surface chemical environment of SCRS, providing mechanical insights for customized design and fabrication of high-performance, application-oriented polyamide membranes towards efficient water treatment.