Fig. 3: Capillary force-driven PM filtration with suppressed bouncing: rapid airflow filtration and suppressed PM resuspension.
From: Bioinspired capillary force-driven super-adhesive filter
a, Schematic of PM capturing behaviours on bare (top) and PRO (bottom) fibres. b–d, FEs of polyester filters for PM1.0 (b), PM2.5 (c) and PM10 (d) across diverse face velocities. Error bars show s.d.; n = 3. Inset in b includes pressure drops corresponding to face velocities before filtration. e,g, High-speed camera images of PM-filtered bare (e) and PRO (g) filters when airflow in the reverse direction is applied: 0 ms (left); 40 ms (middle); and 80 ms (right). f,h, Photographic (left) and SEM (right) images presenting bare (f) and PRO (h) filters after air sweeping. i, Bidirectional PM filtration of the PRO filter. At each cycle, the filter was inverted after measuring the weights of captured PMs. Then, about 170 mg PM was applied again through 2 m s−1 airflow. Error bars show s.d.; n = 3. j, Photograph of multidirectional filtering set-up at a smoking area. k,l, SEM images of bare (k) and PRO (l) filters after 38 months of installation (14 July 2021 to 28 September 2024) at the smoking area. Inset pictures are the photos of filters. Scale bars, 1 cm (e,g); 1 cm (f, left; h, left); 200 μm (f, right; h, right); 100 μm (k,l); 2 cm (k, inset; l, inset).
