Droplet Dynamics and Freezing Delay on Nanoporous Microstructured Surfaces at Condensing Environment

Abstract

Superhydrophobic surfaces have aroused great interest for being promising candidates in applications such as self-cleaning, anti-icing, and corrosion resistance. However, most of the superhydrophobic surfaces lose their anti-wettability in low surface temperature and high humidity. The loss of superhydrophobicity by condensed liquid is a very common practical incident, yet to be understood properly. Here we report the wettability of the superhydrophobic nanoporous surfaces in condensation and freezing environments. Various structured surfaces fabricated with carbon nanotubes (CNT) and coated by an ultrathin, conformal, and low surface energy layer of poly (1H,1H,2H,2H-perfluorodecylacrylate) (pPFDA) are exploited in humid conditions. Droplet impact dynamics, condensate characteristics, and freezing time delays are investigated on the CNT micropillars with various geometries along with the CNT forest and two commercially available anti-wetting coatings, NeverWet and WX2100. Nanoporous microstructured CNT pillars with the favorable topological configuration demonstrated complete droplet bouncing, significant freezing delays, and considerable durability during several icing/de-icing cycles. This study provides an understanding on the preferable geometry of the highly porous CNT micropillars for retaining hydrophobicity and preventing ice formation, which is of practical importance for the rational development of anti-wetting surfaces and their applications in low temperatures and humid conditions.

Recent advances in bioinspired superhydrophobic ice-proof surfaces: challenges and prospects

“…After 50 cycles of sandpaper grinding, the coating still maintained complete superhydrophobic and anti-icing properties. In contrast, Raiyan et al 193 developed various superhydrophobic surfaces with carbon nanotubes and low-surface coatings. The carbon nanotube column had a good topological structure, showed complete droplet bouncing, significant freezing delay, and considerable durability over several icing/de-icing cycles.…”

Anti-corrosion and icephobic approach on rose leaf biomimetic surface

“…The active approaches correspond to removing ice by the external energy systems such as applying thermal systems: hot air [7], resistive heater [8], mechanical removing such as ultrasonic [9], and expulsive method [10]. On the other hand, the passive anti-icing term is often associated with the ease of removing ice formation or even allowing condensation droplets to bounce off the surface before ice nucleation [11,12]. This could be done by using the physicochemical method including the physical texture of the surface and low surface energy chemical compound coating process [13][14][15][16][17][18][19].…”

3D Simulations of Freezing Characteristics of Double-Droplet Impact on Cold Surfaces with Different Wettability

“…This disrupts the aerodynamic properties of the aircraft and, in severe cases, may even lead to the loss of control [ 1 ]. Additionally, the icing problem is a threat to the air-conditioning system [ 2 , 3 , 4 , 5 ], wind turbines [ 6 , 7 , 8 ], and power transmission systems [ 9 , 10 ].…”