We report frozen ice patterns for the water droplets impacting on a cold substrate through high-speed images. These patterns can be manipulated by several physical parameters (the droplet size, falling height, and substrate temperature), and the scaling analysis has a remarkable agreement with the phase diagram. The observed double-concentric toroidal shape is attributed to the correlation between the impacting dynamics and freezing process, as confirmed by the spatiotemporal evolution of the droplet temperature, the identified timescale associated with the morphology and solidification (tinn≃τsol), and the ice front-advection model.
Bibliographical noteFunding Information:
This work was supported by the National Program in China and startup from Fudan University, the National Natural Science Foundation of China (No. 11704077), and the China Postdoctoral Science Foundation (No. 2018T110342). S.M.R. was partially supported by DOE-PNNL under Grant No. 428977.
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