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.

The icephobic performance of alkyl-grafted aluminum surfaces

“…Significantly delayed ice formation [3,10,12,13,15,16,23,26] and reduced ice adhesion or accumulation [3,10,[15][16][17]19,21,25] have been reported for various SHSs. Theoretical models have also been developed, demonstrating how SHSs can delay ice formation from impinging water droplets [9,11,13], which is in good agreement with experimental work [3,14,25,26].…”

“…The design and use of surfaces/coatings with minimum ice adherence and reduced ice accumulation is still actively considered as the most appealing and universal approach to the problem [3,[5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Most of the existing studies on anti-ice surfaces are focused on the reduction of ice adhesion strength [1,[5][6][7][8]10,[19][20][21][22][23][24] or delayed ice nucleation/formation [3,9,12,13,23,25,26]. Therefore lately the research in this area has been chiefly focused on the use and development of superhydrophobic surfaces (SHSs) for preventing ice formation and accumulation [4,[9][10][11][13][14][15][16][17][18][19]…”

“…Most of the existing studies on anti-ice surfaces are focused on the reduction of ice adhesion strength [1,[5][6][7][8]10,[19][20][21][22][23][24] or delayed ice nucleation/formation [3,9,12,13,23,25,26]. Therefore lately the research in this area has been chiefly focused on the use and development of superhydrophobic surfaces (SHSs) for preventing ice formation and accumulation [4,[9][10][11][13][14][15][16][17][18][19][20][21][22][23][25][26][27][28][29]. Significantly delayed ice formation [3,10,12,13,15,16,23,26] and reduced ice adhesion or accumulation [3,…”

“…In parallel, SHSs were reported to lose their anti-icing performance in a humid atmosphere, when icing follows (or occurs simultaneously with) water condensation or frost formation in their rough structures [2,13,16,22,33]. It is now therefore clear that SHSs may only be efficient anti-icing materials under low humidity conditions [9,13,16,22,33], while their use as universal remedy for ice accretion, i.e. under a very wide range of atmospheric conditions, may be very limited [1,2,13,16,22,33].…”

Supercooled Water Droplet Impacting Superhydrophobic Surfaces in the Presence of Cold Air Flow

“…Entrapped air underneath of an impacting water drop on rough surface changes the thermal transport property by increasing thermal resistance due to the low thermal conductivity of entrapped air [12][13][14]. This unique features of superhydrophobic surfaces act as a good insulator [15] used for decreasing solid-liquid interface temperature during the impact of the supercooled water droplet.…”