An experimental investigation on condensation-induced self-cleaning of dust on superhydrophobic surface

Highlights: • A condensation-induced self-cleaning of dust on superhydrophobic surface. • Three consecutive processes are accounted for the self-cleaning including dust agglomerating, condensate sliding and rolling. • Over 95% of particles can be removed by condensate within 90 min in the experiment. The self-cleaning of the superhydrophobic surface (SHS) attracted worldwide interest. However, in most cases it depends on the incoming droplet, which places additional constraints especially in arid area and/or narrow space. Herein, a condensation-induced self-cleaning of dust on the SHS is proposed. First, the SHS are prepared and dust is deposited on the surface, and then the dust removal process is studied on the condensation visualization platform. During condensation, a liquid bridge is initially formed at the contact points between particles on the SHS, which governs dust removal behavior. Specially, three consecutive processes are accounted for the self-cleaning including dust agglomerating, condensate sliding and rolling as the condensate prolongs. As far as the sizes and coverage rate of dust particles are concerned, over 95% of particles can be removed by condensation within 90 min (air temperature 26 ± 0.5 ℃, air humidity 60 ± 5% and cooling-stage temperature 10 ± 0.5 ℃). This study aims to provide a useful, in-depth understanding of dust mitigation by condensation on SHS, which has potential application in PV module and heat exchanger.