The
icephobicity property of multifunctional surfaces has been
widely studied due to their potential application in the aerospace
field. Herein, a controllable CNW/PDMS biomimetic nanocomposite film
with a superhydrophobic surface is fabricated. The microcolumns are
etched on the surface of the biomimetic nanocomposite to provide superhydrophobicity.
Two defense strategies of biomimetic nanocomposites are proposed while
passive anti-icing and active electrothermal deicing behaviors of
the biomimetic nanocomposite are experimentally studied. It is found
that the initial nucleation time of a single water droplet is delayed
by 353.3 s on the superhydrophobic surface relative to the hydrophilic
surface. The adhesion strength increases with the increase of surface
roughness. The heating uniformity on the biomimetic nanocomposite
surface was validated by infrared thermography technology. The ice
layer is completely melted within 150 s under 40 V voltage captured
by a noncontact infrared camera. The proposed strategy was validated
by the characterization of the passive anti-icing and active electrothermal
deicing property from biomimetic nanocomposites with superhydrophobic
microstructure surfaces. Research results show that the two lines
of defense collaborative work for an icephobicity system were able
to keep biomimetic nanocomposite surfaces ice-free under test conditions.
Surface 2019, surface charge density
(SCD) gradient printing-driven
droplet transport, has attracted considerable attention as a novel
and effective approach, which adopts the water droplet impacting a
nonwetting surface to create a reprintable SCD gradient pathway conveniently
and realizes the high-velocity and long-distance transport of droplets.
In the present work, we further investigated the effects of electrothermal
behavior on SCD gradient printing on hydrophobic surfaces by considering
the droplet impact dynamics. After the electrothermal function was
activated, the wettability of the hydrophobic surface improved in
terms of the spreading factor history and the infiltration depth,
which increased the probability of solid/liquid contact electrification
to generate a more favorable SCD gradient. Since the hydrophobic surface
was negatively charged by droplet impact, polarized droplets rolled
forward along the preprinted SCD gradient pathway due to opposite
charge attraction. Based on these results, we designed a SCD gradient
printer with an electrothermal function for hydrophobic surfaces.
Subsequently, the kinematic parameters of rolling droplets on hydrophobic
surfaces were observed and quantified to evaluate the improvements
resulting from the electrothermal function.
Retarding and preventing ice/frost formation have increasing importance in aerospace applications because of widespread energy and safety concerns. In this study, multiwalled carbon nanotube−polydimethylsiloxane (MWCNT/PDMS) nanocomposites were fabricated via mechanical stirring and three-roll grinding. By imitating the microstructures of lotus leaves, various biomimetic nanocomposites were prepared by etching micropillar arrays on MWCNT/PDMS nanocomposites. These biomimetic nanocomposites possess superior flexibility, electrical conductivity, hydrophobicity, and icephobicity. Effects of the micropillar height on the wettability, freezing process of water droplets, ice/frost formation, and ice adhesion strength were characterized; influences of temperature on the wettability and strength of ice adhesion and feasibility of electrothermal deicing were investigated. The surface wettability, freezing process of water droplets, ice/frost formation, and ice adhesion strength in the Cassie state are independent of the micropillar height. However, compared to flat surfaces, the adhesion strength of ice increases, and formation of ice/frost decreases because of the presence of surface micropillars. At the same micropillar height, an increase in temperature decreases the contact angle and ice adhesion strength. The results indicate that the surface microstructure designability and flexible temperature-controllability of biomimetic nanocomposites have great potential for use in aerospace (anti-/deicing) applications.
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