Encapsulation of Nanoscale Organic Hybrid Materials in Electrospun Polymer Fibers for Direct Air CO2 Capture
Nanoscale organic hybrid materials (NOHMs) consisting of a silica core and a corona of ionically grafted polyethyleneimine or tetraethylenepentamine chains were encapsulated within few-micron-scale electrospun fibers composed of PIM-1, a hydrophobic Polymer of Intrinsic Microporosity with excellent CO2 permeability and thermal stability. PIM-1 acts to shield the hydrophilic NOHMs to produce near-superhydrophobic non-woven fiber mats. Control fibers encapsulating the untethered amine chains were also prepared. High loadings of the amine adsorbents are achievable, and nearly all fibers demonstrate exceptional capture capacities in a pure CO2 atmosphere due to the high microporous surface area of the PIM-1 scaffold and low pressure drop through the non-woven fibrous mat. The composite fibers additionally show enhanced capture kinetics and performance retention under 400 ppm CO2 direct air capture conditions.