(544d) Simultaneous Spin Coating and Ring-Opening Metathesis Polymerization for the Rapid Synthesis of Polymer Films

Current methods for synthesizing novel polymeric materials are often time-consuming, resource-intensive, and confined to stringent reaction conditions. Polymerization times can range from hours to days for conversion of monomer into polymer. Additionally, necessary purification steps to isolate the synthesized polymer can further extend the time needed between material synthesis and characterization. Ring-opening metathesis polymerization (ROMP) provides a route to synthesize well-defined polymers with high yields in short times. ROMP with Grubb’s 3^rd generation catalyst (G3) can be conducted in ambient conditions, easing the reaction condition restraints found in common polymerization methods. In this study, we report a novel film synthesis method devised by combining ROMP and spin coating into a process termed scROMP. The scROMP method combines polymer synthesis and deposition into one process, generating films of up to 36 cm² in under 3 min with orders-of-magnitude reduction in solvent usage (<1 mL), enabling a process for rapid polymeric material discovery. We demonstrate that the scROMP process is capable of generating continuous and uniform polymer films atop a rotating substrate using norbornene-type monomers. Further, we determine that polymers generated through scROMP exhibit high molecular weights (M_W > 200 kDa) and low polydispersities (PDI < 1.2). Polymer film thicknesses can be adjusted from tens of microns to hundreds of nanometers by adjusting spin speed and monomer concentration during polymerization. Additionally, a model of the scROMP process was devised to determine the interplay between convective monomer transfer across the surface and polymer film growth kinetics Finally, this method was also translated to porous supports to generate thin film composite membranes (TFC). The synthesized TFC are robust and solvent stable, enabling their use in dehydrating 90/10 v/v% ethanol/water mixtures via pervaporation. Different compositions of polymeric TFC were generated that exhibit selectivity of water over ethanol, with selectivities of >100 observed.