Microphase-Tuned Segmented Polyurethane Porous Architecture for Selective Atmospheric Polycyclic Aromatic Hydrocarbons Capture

Passive air monitoring requires polymer sorbents that combine selective interfacial interactions with fast capture of pollutants. We design porous polyurethane (PU) with tunable aromatic hard-segment (HS) content (MDI:BDO:PCL = 6:5:1, 4.5:5:1, 3:5:1, namely PU-1/PU-2/PU-3) and benchmark them against a commercial foam (C-PU). In these materials, HS domains act as physically cross-linked reinforcements embedded in a soft PCL matrix, or soft-segments (SS), so that the HS fraction/aromaticity governs microphase separation and crystallinity, tunes modulus, and elevates the dispersion component of the surface free energy (SFE). Multiscale characterization establishes a clear structure–property link. PU-2 provides the best balance of mechanical integrity, dispersive SFE = 46.33 ± 0.21 mN m–1, and a controlled pore architecture (∼150–300 μm). In performance reference compound (PRC) calibrated deployments, PU-2 achieves 89.3 ± 6.7% recovery, which is more than twice that of the commercial foam (41.2 ± 6.6%). Field tests confirm superior uptake of low-molecular-weight polycyclic aromatic hydrocarbons, PAHs, (MW < 202 g mol–1), enabling urban–rural discrimination in 17 days (versus ∼ 90 days for commercial foams). These results define a structure–property–performance pathway in which HS aromaticity governs microphase/thermal metrics and SFE, which together control selective uptake, thereby positioning hard-segment tuning as a practical polymer design lever for applied PU sorbents compatible with passive air monitoring requirements.