Advanced Manufacturing of Novel Polymer Membranes Using Direct Ink-Writing

Nhan Khuu, Brian Leonard, Harrison Loh, Konstantinos Sierros and Oishi Sanyal

A novel membrane fabrication strategy was examined utilizing a 3-D printing strategy known as a direct-ink writing (DIW), where a viscous polymer dope solution was extruded and cast on a glass substrate. The purpose of this work is to develop alternate strategies to conventional solvent casting/doctor blading methods for making membranes. The DIW method of fabrication has two distinct advantages over the traditional techniques. – (i) DIW allows precise control of the membrane morphological properties ( pore size distribution, porosity) – (ii) reduction in the amount of material (solvents/co-solvents and polymer) needed. This presentation will cover the effects of various DIW parameters on polysulfone (PSF) membrane separation properties and compare the properties of these membranes with commercially available PSF membranes. These membranes were primarily characterized based on their pure water fluxes and molecular weight cur-offs. Advanced characterization techniques like scanning electron microscopy (SEM) were employed to understand the membrane internal structure and morphology in detail. The stability of the membranes prepared were evaluated and a “low-surface tension solvent-exchange” technique predominantly used for hollow fiber fabrication, was utilized in this work to promote membrane stability. While the current work focusses primarily PSF membranes, these findings could be easily extended to other polymer membranes as well.