Achieving rapid shedding of droplets from solid surfaces has received substantial attention because of its diverse applications.Previous studies have focused on minimizing contact times of liquid droplets interacting ...Achieving rapid shedding of droplets from solid surfaces has received substantial attention because of its diverse applications.Previous studies have focused on minimizing contact times of liquid droplets interacting with stationary surfaces,yet little consideration has been given to that of moving surfaces.Here,we report a different scenario:A water droplet rapidly detaches from micro/nanotextured rotating surfaces in an intriguing doughnut shape,contributing to about 40%contact time reduction compared with that on stationary surfaces.The doughnut-shaped bouncing droplet fragments into satellites and spontaneously scatters,thus avoiding further collision with the substrate.In particular,the contact time is highly dependent on impact velocities of droplets,beyond previous descriptions of classical inertialcapillary scaling law.Our results not only deepen the fundamental understanding of droplet dynamics on moving surfaces but also suggest a synergistic mechanism to actively regulate the contact time by coupling the kinematics of droplet impingement and surface rotation.展开更多
基金supported by the National NaturalScience Foundation of China(nos.52005128 and 11921002)China Postdoctoral Science Foundation(nos.2021 M690833 and2021 M701905)Shenzhen Science and Technology Program(nos.KQTD20210811090146075 and JCYJ20210324132810026).
文摘Achieving rapid shedding of droplets from solid surfaces has received substantial attention because of its diverse applications.Previous studies have focused on minimizing contact times of liquid droplets interacting with stationary surfaces,yet little consideration has been given to that of moving surfaces.Here,we report a different scenario:A water droplet rapidly detaches from micro/nanotextured rotating surfaces in an intriguing doughnut shape,contributing to about 40%contact time reduction compared with that on stationary surfaces.The doughnut-shaped bouncing droplet fragments into satellites and spontaneously scatters,thus avoiding further collision with the substrate.In particular,the contact time is highly dependent on impact velocities of droplets,beyond previous descriptions of classical inertialcapillary scaling law.Our results not only deepen the fundamental understanding of droplet dynamics on moving surfaces but also suggest a synergistic mechanism to actively regulate the contact time by coupling the kinematics of droplet impingement and surface rotation.
