Effect of spin-coated and blade-casted MXene-polydimethylsiloxane asymmetric thin film composite membranes towards effective H2 and CO2 separation performance involving quaternary gas mixture

Abstract

Mixed-matrix membranes (MMMs) have been widely studied for gas separation. However, MMMs have been mainly developed in a dense symmetric manner. Hence, such membranes suffer from high gas transport resistance, limiting their practical applicability. Thus, asymmetric MMMs were prepared by embedding MXene into a polymer matrix using the blade casting and spin coating method. The differences in the gas permeation were observed despite utilizing the identical dope solution and membrane thickness. Spin-coated membranes showed uniformly dispersed but randomly aligned MXene, forming loosely packed layers that facilitate gas transport. In contrast, blade-cast membranes exhibited dense and highly aligned MXene that hinders the permeation of gas molecules. Consequently, spin-coated membranes achieved higher H<inf>2</inf> and CO<inf>2</inf> (1.9 and 1.8 times) permeance and selectivity (H<inf>2</inf>/N<inf>2</inf> (9.7) and CO<inf>2</inf>/N<inf>2</inf> (17.5)) as compared to blade-cast membranes. These results underscore the critical role of utilizing appropriate coating methods to optimize the gas separation performance. © 2025 Hydrogen Energy Publications LLC