High-Throughput Particulate Matter Capturing and Moisture Wicking by Hierarchical Janus Poly(lactic acid) Sensing Meta-Membranes with Gradient Pores and Interfacial Polarization

Facing persistent airborne particulate matter (PM) pollution, ideal respiratory protection materials must simultaneously offer high-efficiency filtration of ultrafine PMs, low breathing resistance, and effective moisture management. However, traditional melt-blown filters are still challenged by poor property balance. Herein, a hierarchical Janus meta-membrane (HJMM) by gradient pore-structured and interfacial polarized poly(lactic acid) (PLA) nanofibers is developed for high-throughput air filtration and rapid moisture wicking. The membranes were assembled by a hydrophilic sodium alginate-functionalized PLA outer layer with submicroporous architecture (∼0.8 μm) and a superhydrophobic polydopamine (SPDA)-PLA composite inner layer with micropore structure (∼1.7 μm). This asymmetric design conferred a unidirectional moisture transport pathway, achieving an ultrahigh water evaporation rate of 110 g m^-2 h^-1 for rapid moisture wicking and evaporation. Moreover, the embedded SPDA nanoparticles significantly enhanced charge trap density and interfacial polarization, contributing to electrostatic adsorption of ultrafine PMs. Given the combination of cascaded physical capture and electrostatic adsorption mechanisms, the HJMM demonstrated high filtration efficiency (99.2% for PM_0.3) and low air resistance (44 Pa, 32 L/min), accompanied by excellent biodegradability that could alleviate environmental burdens associated with plastic pollution. Furthermore, the high electroactivity of the HJMM enabled self-powered respiratory monitoring, allowing real-time detection of breathing patterns without an external power supply. This work provided an effective strategy for reconciling high-throughput PM removal, superior moisture management, and self-powered respiratory monitoring toward challenging protective applications, appealing for next-generation respiratory protection equipment and sustainable materials solutions.