title: Dynamics of ice nucleation on water repellent surfaces.
abstract: Prevention of ice accretion and adhesion on surfaces is relevant to many applications, leading to improved operation safety, increased energy efficiency, and cost reduction. Development of passive nonicing coatings is highly desirable, since current antiicing strategies are energy and cost intensive. Superhydrophobicity has been proposed as a lead passive nonicing strategy, yet the exact mechanism of delayed icing on these surfaces is not clearly understood. In this work, we present an in-depth analysis of ice formation dynamics upon water droplet impact on surfaces with different wettabilities. We experimentally demonstrate that ice nucleation under low-humidity conditions can be delayed through control of surface chemistry and texture. Combining infrared (IR) thermometry and high-speed photography, we observe that the reduction of water-surface contact area on superhydrophobic surfaces plays a dual role in delaying nucleation: first by reducing heat transfer and second by reducing the probability of heterogeneous nucleation at the water-substrate interface. This work also includes an analysis (based on classical nucleation theory) to estimate various homogeneous and heterogeneous nucleation rates in icing situations. The key finding is that ice nucleation delay on superhydrophobic surfaces is more prominent at moderate degrees of supercooling, while closer to the homogeneous nucleation temperature, bulk and air-water interface nucleation effects become equally important. The study presented here offers a comprehensive perspective on the efficacy of textured surfaces for nonicing applications.
authors.affiliation: General Electric Global Research, Niskayuna, New York 12309, United States. Alizadeh@research.ge.com
authors.forename: Azar
authors.initials: A
authors.lastname: Alizadeh
authors.forename: Masako
authors.initials: M
authors.lastname: Yamada
authors.forename: Ri
authors.initials: R
authors.lastname: Li
authors.forename: Wen
authors.initials: W
authors.lastname: Shang
authors.forename: Shourya
authors.initials: S
authors.lastname: Otta
authors.forename: Sheng
authors.initials: S
authors.lastname: Zhong
authors.forename: Liehui
authors.initials: L
authors.lastname: Ge
authors.forename: Ali
authors.initials: A
authors.lastname: Dhinojwala
authors.forename: Ken R
authors.initials: KR
authors.lastname: Conway
authors.forename: Vaibhav
authors.initials: V
authors.lastname: Bahadur
authors.forename: A Joseph
authors.initials: AJ
authors.lastname: Vinciquerra
authors.forename: Brian
authors.initials: B
authors.lastname: Stephens
authors.forename: Margaret L
authors.initials: ML
authors.lastname: Blohm