(408b) Customized thin film composite membranes using additive manufacturing

We proposed a novel additive manufacturing method to make thickness-controllable thin film composite membranes (TFCs) from a variety of polymers (even those not traditionally considered for TFCs). Conventional membrane fabrication techniques, such as phase inversion and interfacial polymerization, usually lack resolution for thickness and roughness control and are often short of material compatibility when a sub-100 nm film is desired. Our novel additive manufacturing technique employs an electrospray 3D printer that precisely deposits materials on a membrane substrate to achieve sub-5 nm thickness resolution and produces membranes with exceptional permeance and selectivity. In our work, we have demonstrated that electrospray additive manufacturing achieves the highest resolution (for thickness control) among all other 3D printing techniques considered for membrane production. Due to its advantageous printing resolution and wide material compatibility, our approach has enabled us to print multiple membrane materials for a variety of applications, including polyamide reverse osmosis (RO) membranes, zwitterionic copolymer nanofiltration (NF) membranes with exceptional permeance, and polyepoxyether NF membrane with robust chlorine tolerance.