(383aa) Distributing Localized Charge and Polarity in Hydrophobic Copolymer Membranes By Spin Coating Ring-Opening Metathesis Polymerization

High stability and minimal swelling make semifluorinated thin film composites attractive separating materials for commercially relevant separations like polar solvent dehydration. Unfortunately, due to their solvent resistant nature, semifluorinated membranes exhibit fluxes that are often considered too low to be practical substitutes for traditional thermal separating methods. One strategy to increase flux in a semifluorinated system is to distribute localized charge or polarity via copolymerization with a more hydrophilic monomer. In this work, poly((5-perfluorohexyl)norbornene-co-(5-norbornene-2,3-dicarbonyl chloride)) (p(NBF6-co-NBDAC)) films were synthesized by combining spin coating with ring-opening metathesis polymerization (scROMP) for use as membranes for ethanol dehydration. scROMP combines polymer film synthesis and deposition into one rapid process, converting monomer into polymer films in under 2 min with < 1/2 mL of solvent and facilitating polymeric materials discovery. The semifluorinated NBF6 monomer of the copolymer stabilizes the membrane from excessive swelling while each NBDAC monomer provides two modifiable acyl chloride groups that can be readily converted to hydrophilic groups upon immersion in modifiers such as hydroxyamic acid, ethanolamine, and taurine. Transmission IR shows that that the compositions of these modified p(NBF6-co-NBDAC) films can be varied by changing the ratio of the two reagents, allowing the overall level of hydrophilicity of the films to be adjusted by either changing the NBF6:NBDAC monomer ratio or the modifying solution. These copolymers exhibit high selectivities while maintaining moderate permeate fluxes from the localized charge and polarity of the interspersed modified NBDAC groups within the hydrophobic matrix.