(95d) Additive Manufacturing of Customized Thin Film Composite Membranes

The way that we manufacture membranes has changed little in over 40 years. Membrane manufacturing is largely limited to casting, spinning, extrusion, and interfacial polymerization. Many of these processes can only process a limited subset of materials. In fact, most commercial membrane applications (e.g. gas separations, water treatment, ion conductive membranes) use a limited number of materials. This is remarkable given the explosion of materials discovery research in membrane science today. It begs the question: why are new materials not making it into commercial membrane products? I believe it is because these new materials cannot be processed with legacy manufacturing approaches. The emergence of additive manufacturing has driven new concepts around membrane manufacturing that may enable the use of new materials in high performance membranes. Additive manufacturing confers a number of benefits including customizability, thickness control, morphology control, and hierarchical design. Our work has identified electrospray printing amongst the most promising additive manufacturing approaches for making membranes. Electrospray printing is capable of producing ultra-thin, defect free films of any solution processable polymer or polymer precursor. The ability to produce a defect free thin film enables the making of what are known as thin film composite (TFC) membranes from a variety of polymer materials. Our work demonstrates fabrication of TFC membranes from a variety of materials for applications in RO, nanofiltration, gas separations, and ion exchange. We contextualize this work in the broader perspective of membrane manufacturing needs.