Break

Membrane technologies can offer an order of magnitude greater energy efficiency than thermally driven separations such as distillation. The fabrication of robust, solvent-stable active layers on polymeric membranes is essential for the insertion of this technology into industry. To generate robust films, we introduce a method known as spin coating ring opening metathesis polymerization (scROMP) of 5-(perfluoro-n-alkyl)norbornenes (NBFn) with perfluoroalkyl side chain lengths (n) of 4, 6, 8, and 10 on a polyacrylonitrile (PAN) support. The scROMP method combines the polymerization and deposition of the membrane selective layer into a rapid and sustainable 2 min process. The polymer films grown by this innovative new method were then characterized and their effectiveness as pervaporation membranes for the dehydration of a 90 wt% aqueous ethanol solution was analyzed. pNBFn membranes exhibited greater solvent stability than their polynorbornene (pNB; n = 0) counterpart while retaining excellent thermal stability, evidenced by reduced swelling and membrane selectivities independent of operating temperature. Furthermore, pNBF8 has shown the greatest promise for ethanol dehydration, obtaining a selectivity of 177 and a flux of 180 g/m²h while showing the ability to maintain a high level of performance after >40 h of continuous operation for ethanol/water separations. This study successfully demonstrates the ability of the scROMP technique to screen specialty polymers efficiently and effectively for membrane applications and sets the stage for additional research into the use of pNBF8 membranes for other chemical separations.