Freezing of few nanometers water droplets

• Published in: Nature communications 2021-11, Vol.12 (1), p.6973-8, Article 6973
• Main Authors: Hakimian, Alireza, Mohebinia, Mohammadjavad, Nazari, Masoumeh, Davoodabadi, Ali, Nazifi, Sina, Huang, Zixu, Bao, Jiming, Ghasemi, Hadi
• Format: Article
• Language: English
• Subjects: 142/136; 147/3; 639/638/440/94; 639/766/94; 639/925/357; Climate change; Clouds; Computer applications; Cryopreservation; Deformation; Deicing; Droplets; Freezing; Humanities and Social Sciences; Ice formation; Ice nucleation; Interfaces; Membranes; Microphysics; multidisciplinary; Nucleation; Science; Science (multidisciplinary); Solid surfaces; Spectrum analysis; Surfactants; Temperature dependence; Transformation temperature; Water drops; Wind power
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-27346-w

Water-ice transformation of few nm nanodroplets plays a critical role in nature including climate change, microphysics of clouds, survival mechanism of animals in cold environments, and a broad spectrum of technologies. In most of these scenarios, water-ice transformation occurs in a heterogenous mode where nanodroplets are in contact with another medium. Despite computational efforts, experimental probing of this transformation at few nm scales remains unresolved. Here, we report direct probing of water-ice transformation down to 2 nm scale and the length-scale dependence of transformation temperature through two independent metrologies. The transformation temperature shows a sharp length dependence in nanodroplets smaller than 10 nm and for 2 nm droplet, this temperature falls below the homogenous bulk nucleation limit. Contrary to nucleation on curved rigid solid surfaces, ice formation on soft interfaces (omnipresent in nature) can deform the interface leading to suppression of ice nucleation. For soft interfaces, ice nucleation temperature depends on surface modulus. Considering the interfacial deformation, the findings are in good agreement with predictions of classical nucleation theory. This understanding contributes to a greater knowledge of natural phenomena and rational design of anti-icing systems for aviation, wind energy and infrastructures and even cryopreservation systems. Ice nucleation in confined geometries is a ubiquitous phenomenon, but difficult to characterize. Here the authors investigate experimentally the freezing of water nanodroplets surrounded by octane in nanopores down to 2 nm, and demonstrate that the soft curved oil-water interface suppresses heterogeneous ice nucleation, which occurs at a lower temperature than homogenous bulk nucleation.