The role of support layer properties on the fabrication and performance of thin-film composite membranes: The significance of selective layer-support layer connectivity

Membrane-based separation processes such as reverse osmosis (RO), forward osmosis (FO), and nanofiltration (NF) are the key technologies for the desalination of brackish and seawater. Along these lines, the thin-film composite (TFC) membranes, prepared via interfacial polymerization (IP), are the predominant choice of the separator; nonetheless, the progress with the optimization of their performance has been fairly slow. This slow progress has been mainly associated with the large number of the parameters influencing IP and the need to control thin-film properties at a miniature length scale, where the trade-off between transport rate and selectivity defines the separation performance. Despite the continuous efforts and progresses made, the role of interfacial, physicochemical, and structural properties of the supports layer on the selective layer fabrication and overally the TFC membranes performance is not a well-attended topic. In this short perspective, we outline the efforts and directions that have been explored and provide insights into this aspect of membrane fabrication. We highlight the significance of selective layer-support layer connectivity on the properties of TFC membranes. Given the challenges associated with separation efficiency, insights on how to adjust the transport properties of TFC membranes are critical to the design, fabrication, and development of future water purification processes.