Encapsulation of Nanoparticle Organic Hybrid Materials within Electrospun Hydrophobic Polymer/Ceramic Fibers for Enhanced CO2 Capture

Liquid-like nanoparticle organic hybrid materials (NOHMs) consisting of a silica core with ionically grafted branched polyethyleneimine chains (referred to as NIPEI) are encapsulated within submicron-scale polyacrylonitrile (PAN)/polymer-derived-ceramic electrospun fibers. The addition of a room-temperature curable, liquid-phase organopolysilazane (OPSZ) ceramic precursor to the PAN/NOHM solution enhances the internal dispersion of NOHMs and forms a thin ceramic sheath layer on the fiber exterior, shielding the hydrophilic NIPEI to produce near-superhydrophobic non-woven fiber mats with contact angles exceeding 140°. 60:40 loadings of NOHMs to PAN/OPSZ can be reliably achieved with low OPSZ percentages required, and up to 4:1 NOHM:polymer loadings are possible before losing hydrophobicity. These fibers demonstrate up to ≈2 mmol CO₂ g⁻¹ fiber capture capacities in a pure CO₂ atmosphere through the nonwoven fibrous networks and the permeability of the OPSZ shell. The hybrid fibers additionally show enhanced capture kinetics under pure CO₂ and 400 ppm CO₂ conditions, indicating their promising application as a direct air capture platform.