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Title: Nonthermal ice nucleation observed at distorted contact lines of supercooled water drops

Ice nucleation is the crucial step for ice formation in atmospheric clouds and therefore underlies climatologically relevant precipitation and radiative properties. Some progress has been made in understanding the roles of temperature, supersaturation, and material properties, but an explanation for the efficient ice nucleation occurring when a particle contacts a supercooled water drop has been elusive for over half a century. Here, we explore ice nucleation initiated at constant temperature and observe that mechanical agitation induces freezing of supercooled water drops at distorted contact lines. Results show that symmetric motion of supercooled water on a vertically oscillating substrate does not freeze, no matter how we agitate it. However, when the moving contact line is distorted with the help of trace amounts of oil or inhomogeneous pinning on the substrate, freezing can occur at temperatures much higher than in a static droplet, equivalent to ~1010 increase in nucleation rate. Several possible mechanisms are proposed to explain the observations. One plausible explanation among them, decreased pressure due to interface curvature, is explored theoretically and compared with the observational results quasiquantitatively. Indeed, the observed freezing-temperature increase scales with contact line speed in a manner consistent with the pressure hypothesis. Whatever the mechanism, themore » experiments demonstrate a strong preference for ice nucleation at three-phase contact lines compared to the two-phase interface, and they also show that movement and distortion of the contact line are necessary contributions to stimulating the nucleation process.« less
ORCiD logo [1] ;  [2] ;  [3] ;  [4] ;  [4]
  1. Michigan Technological Univ., Houghton, MI (United States). Dept. of Physics and Atmospheric Sciences Program; Brookhaven National Lab. (BNL), Upton, NY (United States)
  2. Michigan Technological Univ., Houghton, MI (United States). Dept. of Physics
  3. Michigan Technological Univ., Houghton, MI (United States). Dept. of Biomedical Engineering
  4. Michigan Technological Univ., Houghton, MI (United States). Dept. of Physics and Atmospheric Sciences Program
Publication Date:
Report Number(s):
Journal ID: ISSN 2470-0045; PLEEE8
Grant/Contract Number:
SC0012704; SC0011690; AGS-1639868
Accepted Manuscript
Journal Name:
Physical Review E
Additional Journal Information:
Journal Volume: 97; Journal Issue: 2; Journal ID: ISSN 2470-0045
American Physical Society (APS)
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); National Science Foundation (NSF)
Country of Publication:
United States
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1419697