Bioinspired capillary force-driven super-adhesive filter

Capturing particles with low, nanonewton-scale adhesion is an ongoing challenge for conventional air filters^1,2. Inspired by the natural filtration abilities of mucus-coated nasal hairs^3,4, we introduce an efficient, biomimetic filter that exploits a thin liquid coating. Here we show that a stable thin liquid layer is formed on several filter media that generates enhanced particulate adhesion, driven by micronewton to sub-micronewton capillary forces^5,6. Enhanced particle adhesion increases the filtration of airborne particulates while maintaining air permeability, providing longer filter lifetime and increased energy savings. Moreover, strong adhesion of the captured particles enables effective filtration under high-speed airflow as well as suppression of particle redispersion. We anticipate that these filters with thin liquid layers afford a new way to innovate particulate matter filtering systems.