Excellent Anti-icing Properties Research Articles

A highly transparent and photothermal composite coating for effective anti-/de-icing of glass surfaces.

Anti-/de-icing of glass surfaces is of great importance in present daily life. The long-standing challenge in this field is largely due to the lack of stable multifunctional coatings that can be conveniently and economically constructed on the glass surface, and more importantly, are capable of retaining the original transparency of glass ranging from the visible to the near infrared spectrum. Herein, a direct spraying sol method on the glass surface to prepare a highly transparent and photothermal composite coating is reported. Such multifunctional coating of Cu7S4 nanoparticles/organo-silicone sols has displayed a good photothermal conversion property and hydrophobic property and therefore yields excellent anti-icing and self-melting ice properties. The condensation time of water droplets can be extended to 86 s even at −10 °C, which is 3.42 times delayed relative to ordinary blank glass. And the adhesion strength of ice is largely reduced to 72 KPa, which is as low as ∼1/3 that of ordinary glass. Meanwhile, the subcooling of adhering droplets is reduced to −12 °C under one solar illumination condition and exhibits a rapid de-icing capability. More impressively, the prepared functional coating glass shows an outstanding transmittance of more than 75% in the visible region, while it is over the minimum glass transmittance limit allowed by Safety Standards for Glass (GB9656-2016, China). In addition, the multifunctional photothermal glass coating exhibits good physical/chemical stability, which facilitates the long-term application of the coating in different environments.

In-Situ Fabrication of Superhydrophobic Surface on Copper with Excellent Anti-Icing and Anti-Corrosion Properties

In-Situ Fabrication of Superhydrophobic Surface on Copper with Excellent Anti-Icing and Anti-Corrosion Properties

Transparent Organogel Films Showing Extremely Efficient and Durable Anti-Icing Performance.

Accumulation of ice and snow on solid surfaces causes destructive problems in our daily life. Therefore, the development of functional coatings/surfaces that can effectively prevent ice/snow adhesion by natural forces, such as airflow, vibration, solar radiation, or gravity, is in high demand. In this study, transparent organogel films possessing negligible ice adhesion strength were successfully designed by a simple cross-linking of poly(dimethylsiloxane) (PDMS) in the presence of commercially available oils. Both the molecular weights (MWs) of the infusing oils and their contents in the PDMS matrices have proven to be key parameters for primarily determining the cross-linking density of PDMS matrices and syneresis/nonsyneresis behaviors of our samples, which closely reflected the final surface static/dynamic dewetting and anti-icing properties. By tuning only these two parameters, three different types of transparent organogel films, that is, nonsyneresis organogel (NSG), self-lubricating organogel (SLUG-I, infused with highly mobile oils), and SLUG-II (infused with viscous oils) films, were prepared. Among them, on the SLUG-I films, the lubricating oils were found to be continuously released from the PDMS matrices through syneresis for more than 1 year. Due to this unusual syneresis behavior, the ice adhesion strength became virtually zero, and this excellent anti-icing property also remained almost unchanged even after several cycles of icing/deicing testing. On the other hand, in the case of SLUG-II films, as the lubricated oil layers were too viscous, ice had trouble sliding off the surfaces by gravity. In contrast to these SLUG films, ice adhesion strength on NSG films was markedly decreased by increasing the amount of the infusing oils. In spite of NSG films having no distinct mobile oil layer, the ice adhesion strength reached its minimum of only about 5 kPa.

Fabrication and characterization of multiscale spherical artificial compound eye with self-cleaning and anti-icing properties

The self-cleaning and de-icing phenomenon is magical in nature, and of practical importance in daily life and industrial activities. The paper studies the inclined impact behaviour of drop on the various surfaces, i.e., micronano hierarchy and multiscale artificial compound eye (ACE). The droplet experiences first spreading, then retract, and finally detach from the surface with different contact time, which results from the different solid fraction tuned by chemical time. Moreover, the anti-icing property of the hierarchical surfaces was further demonstrated and discussed. Results show that the hierarchical surfaces endow excellent anti-icing properties compared with the planar surface. For reaction time of 40 min, the hierarchy has delay time of 800 s, which almost three times the planar surface. Further, curved ACE was fabricated by laser swelling, gas-assisted deformation and chemical growth. The nanohairs was fully covered on the surface of ACE. The imaging property was tested in the experiment. The nanohairs greatly enhance the hydrophobicity compared with the regular ACE. The contact angles for regular ACE and ACE with nanohairs was 105°and 160°, respectively. Besides the static hydrophobic performance, the dynamic dewetting behavior is also tested. For regular ACE, the contact droplets stick to the surface; while for ACE with nanohairs, the droplets fully detach the curved surface with a contact time of ~ 8.75 ms for Weber number (We) of 66. These findings are believed to provide guideline for preparation of surfaces for both self-cleaning and anti-icing purposes and paves the way for practical applications of the ACE.

Triple-Scale Superhydrophobic Surface with Excellent Anti-Icing and Icephobic Performance via Ultrafast Laser Hybrid Fabrication.

Passive anti-icing or icephobic superhydrophobic surfaces have attracted great interest due to their potential multifaceted implications for the prevention and/or easy removal of undesired ice in many applications. However, a superhydrophobic surface with both excellent anti-icing and icephobic performances has rarely been reported due to difficulties in sustaining a good Cassie state stability. This is the case especially under high humidity and freezing environment conditions. In the present study, a new triple-scale micro/nanostructured superhydrophobic surface with both excellent anti-icing and icephobic properties has been designed via a hybrid method, combining ultrafast laser ablation and chemical oxidation. The novel surface structure is composed of periodical microcone arrays covered with densely grown nanograsses and dispersedly distributed microflowers. This surface exhibits an excellent Cassie state stability with its critical Laplace pressure reaching up to 1450 Pa, which is essential for good anti-icing and icephobic performances. The anti-icing feature of the prepared superhydrophobic surface is achieved by a rapid rolling-off of the impacting droplets. Moreover, an excellent resistance to the impact of high humidity has been achieved via hierarchical condensation, coalescence-induced jumping, and upward moving. A good delay of the heterogeneous nucleation at the solid-liquid interface under freezing condition has been registered as well, due to the presence of stable air pockets within the surface structures. In addition, the ice adhesion strength of the prepared superhydrophobic surface can be as low as 1.7 kPa, which is the lowest value when compared with the state-of-the-art superhydrophobic surfaces. Such a low ice adhesion strength allows the ice to be easily removed by its own weight and demonstrates an excellent icephobic performance. The repeated icing-deicing tests indicate a decent deicing robustness of the synthesized superhydrophobic surface. Thus, this triple-scale superhydrophobic surface exhibits a good anti-icing and icephobic performance with an excellent Cassie state stability, high humidity resistance, and good deicing durability. We hypothesize that the proposed fabrication strategy and associated basic findings will shed new light on the design of robust ice-resistant superhydrophobic surfaces and contribute to a better understanding of the relationship between superhydrophobicity and ice resistance.

전력설비 동결 방지를 위한 액적 반동 현상 기반 방빙 기술

In winter, electric power facilities such as solar panels, substations, power towers, and power lines suffer from freezing or ice accumulation problems due to exposure to harsh external environments. These problems result in unstable power supply, high maintenance costs, and severe economic and social losses. To address these problems, diverse anti-icing or deicing techniques including physical, thermal, and chemical approaches have been developed. However, these conventional approaches have limitations such as requirements for additional external energy, environmental toxicity, and low applicability. Recently, novel anti-icing surfaces based on unique drop bouncing dynamics have been developed by mimicking nano/micro-structures of natural systems. These anti-icing surfaces have attracted attention due to their high energy efficiency and environmental friendliness. It has been found that the superhydrophobic surfaces with specific nano/micro-structures can effectively remove the water droplets before the formation of ice nucleation by minimizing contact area and contact time between the droplets and the surface, thereby demonstrating excellent anti-icing properties. This review introduces recently developed anti-icing techniques based on the drop bouncing dynamics, and briefly describes the future direction of the anti-icing technology for stable power supply.

Robust superhydrophobic surface for anti-icing and cooling performance: Application of fluorine-modified TiO2 and fumed SiO2

Micron/nano-structures and surface layer enriched with organic groups were flexibly obtained through the non-solvent induced phase separation method. A combination of surface roughness and surface chemistry enabled the surface with superhydrophobic performance, which contributed to excellent anti-icing property. Herein, the simultaneous application of fluorine-modified titanium dioxide (TiO2) and fumed silicon (SiO2) contributed to the superhydrophobicity with the water contact angle of 161°, as well as the freezing delay time of about 93 min. Simultaneously, this desirable anti-icing property based on the superhydrophobic surface was combined with excellent reflective performance to fabricate well-designed cool materials. The cooling property of the as-prepared cool material, which presented high solar reflectance of 101.1% in visible (VIS) light wavelength and 75.6% in the near infrared (NIR) light wavelength, was estimated to be 8 °C lower than that of pristine polymer matrix. Hence, superhydrophobic surface with desirable anti-icing property was successfully obtained, and the simultaneous cooling property might highlight its outdoor applicability in the locations both experiencing cold winter and sunny summer. For instance, the superhydrophobic material combined with the anti-icing and cooling performance is expected to be utilized as roofing materials, as well as station antenna covers.

Robust and durable surperhydrophobic F-DLC coating for anti-icing in aircrafts engineering

The nose cones of plane engines adjust the airflow direction and guarantee steady operation but they are vulnerable to icing at high altitude leading to potential hazards and accidents. Superhydrophobicity is effective against icing but most organic superhydrophobic materials are not suitable for engineering applications. Herein, a mechanically robust superhydrophobic coating is prepared on stainless steel by incorporating laser-textured micro/nano structures into the plasma-coated multilayered structure of Cr/CrC/DLC/F-DLC. The multilayered coating shows a stable surface contact angle of >150° in addition of robust mechanical properties even in harsh environments such as prolonged ultraviolet light irradiation, wear, and corrosion. Tests conducted under simulated working conditions reveal significantly reduced ice accumulation on the coating because of easy roll-off of droplets consequently giving rise to excellent anti-icing properties.

Fabrication of modifier-free superhydrophobic surfaces with anti-icing and self-cleaning properties on Ti substrate by anodization method

Superhydrophobic titanium (Ti) and its alloys have attracted considerable attention due to their application potentials; however, it is very difficult to obtain directly superhydrophobic surfaces on the Ti substrate by the anodization method. In the present work, TiO2 pinecone-like micro/nanostructures (TPSs) were fabricated on the Ti substrate by the anodization method. It was found that the sample surfaces without chemical modification were superhydrophilic and then became superhydrophobic after their exposure to air for a long time. After the high-temperature annealing treatment, the time required for the superhydrophilic to superhydrophobic wettability transition with the maximum water contact angle (WCA) of ~153° and sliding angle (SA) of ~0° was reduced from 81 days to 63 days. The surface chemistry and morphology analysis indicated that the wettability transition mainly occurred by the adsorption of organic compounds from ambient air and the trapped air in the microstructure. Furthermore, the superhydrophobic surfaces had excellent anti-icing and self-cleaning properties and long-term stability

Aluminium alloy processed by square‐column composite structure and its anti‐icing characteristics

To prepare surfaces with stable anti-icing properties, square-column micro/nanocomposite structures were fabricated using wire-cut electrical discharge machining. Smooth and hydrophobic/superhydrophobic surfaces were tested for wettability and were subjected to mechanistic analysis. Droplets were found to produce an `air cushion effect' upon contact with the microstructure, which reduced the contact area between the droplets and the aluminium substrate and increased the contact angle of the droplets on the surface. The icing experiment quantitatively evaluated the anti-icing performance of the surfaces by observing the cooling time and out-of-phase icing time of water droplets. It was found that the anti-icing effect is influenced by the wettability of the material and that the superhydrophobic surface has excellent anti-icing properties. Combined with the one-dimensional heat transfer theory for analysing the mechanism of icing, the results show that the `air cushion' reduces the heat transfer between the solid and liquid and increases the thermodynamic barrier to ice core formation. The stability of the sample surface was tested by icing-melting experiments and friction experiments, and the test piece exhibited stable wettability and anti-icing performance.

Anti-Icing Properties of Vertically Aligned TiO2 Nanopillars.

Inspired by the superhydrophobic and anti-icing properties of Berberis thunbergii leaves for the first time, a surface with vertically aligned TiO2 nanopillars (VATiO2NPIs) has been developed, which shows excellent anti-icing properties even at -25 °C. The height and diameter of TiO2NPIs arrays were 200 and 70 nm, respectively, and were fabricated using TiO2 atomic-layer deposition in an aqueous solution on an anodized aluminum oxide substrate and modified with stearic acid. The water contact angle measurements for VATiO2NPI-based aluminum surfaces indicated high contact angle (170.2°), low contact angle hysteresis (5°), excellent delay time (385 s), appropriate robustness (>20 cycles of freeze-melt), and low adhesion strength (<95 kPa). The VATiO2NPI surface analyses were done using energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction spectroscopy (XRD), and Fourier transform infrared spectroscopy (FT-IR) methods, and they showed that the stearic acid stably absorbed on VATiO2NPIs. Our results indicated that the long delay time of the heterogeneous nucleation and freezing process could be obtained by the desired structural match between the VATiO2NPI apices and water molecules in the initiation of the heterogeneous nucleation. In this study, smooth apices of the VATiO2NPIs with highly potent morphology presented significant anti-icing properties because of the strong phonon scattering between nanopillars that can interrupt the heat transfer process. Such results are not achievable by conventional anti-icing methods and give new insight into the mechanism of the anti-icing process.

Preparation and Anti-Icing of Hydrophobic Polypyrrole Coatings on Wind Turbine Blade

This paper describes the method of preparing strong hydrophobic polypyrrole (PPy) on wind turbine blades. The water contact angle of strong hydrophobic PPy coatings was 127.2°. The strong hydrophobic PPy coatings exhibited excellent anti-icing properties. The maximum icing weight of strong hydrophobic PPy coating blade was almost 0.10 g while the maximum icing weight of no coating blade was found to be 26.13 g. The maximum icing thickness of a strong hydrophobic PPy coating blade was only 1.08 mm. The current research will provide a better technique to create anti-icing coatings on wind turbine blades and other outdoor equipment.

One-Step Fabrication of Robust Superhydrophobic Steel Surfaces with Mechanical Durability, Thermal Stability, and Anti-icing Function.

Superhydrophobic metallic materials have drawn broad research interest because of promising applications in various fields. The mechanical stability of superhydrophobic surfaces is currently a major concern limiting their practical applications. Herein, we developed a simple method to fabricate robust superhydrophobic surfaces on stainless steel via direct ultrafast laser microprocessing. Of note is that the fabricated superhydrophobic surfaces can withstand mechanical abrasion against an 800 grit SiC sandpaper for 2.3 m at an applied pressure of 5.5 kPa without losing superhydrophobicity. It is proposed that the robust superhydrophobicity may be attributable to the formation of unique hierarchical micro-/nanostructures and a nonpolar carbon layer on the surface. The hierarchical structures are composed of laser-created micropillars and ablation-induced nanoparticles. The fabricated surfaces exhibit good thermal stability and still show superhydrophobicity after thermal treatment at 100 °C for 120 min, which is related to the inorganic nature of metallic materials. An excellent anti-icing property is achieved on the fabricated surfaces with the water droplets on it retaining the liquid state for over 500 min at -8.5 ± 0.5 °C, which benefits from the obtained superhydrophobicity, based on classic nucleation theory and the heat transfer between the rough solid surface and water droplet. We envision that the presented method provides a facile and effective route to fabricate large-area superhydrophobic surfaces with robust mechanical stability and excellent anti-icing property.

Antiicing Properties of Bioinspired Liquid‐Infused Double‐Layer Surface with Internal Wetting Transport Ability

AbstractInspired by the poison dart frog skin that secretes functional liquid after being stimulated, a liquid‐infused double‐layer surface (LDS) is designed by integrating superhydrophobic layer with liquid‐infused layer. Both layers generate the wettability gradient to drive tiny condensed droplet into the liquid‐infused layer, and the liquid‐infused layer would effectively lower the freezing point for nonicing. Especially, the internal wetting transport ability appears between both layers, greatly reducing icing possibility of the surface, i.e., the tiny condensed droplets in the micropores can be transported to liquid‐infused layer with nonfrozen properties. Thus, the surface of LDS thereby keeps superhydrophobic property for antiicing and antifrosting in a long term. This design makes LDS achieve excellent antiicing and antifrosting properties against cold environments with high humidity. And it may be significant for such materials to be extended into some realms, e.g., antiicing in aviation and power for long‐term durability in cold and high moisture environment.

Fluorine modification on titanium dioxide particles: Improving the anti-icing performance through a very hydrophobic surface

In this study, fluorine modification was successfully conducted on titanium dioxide (TiO2) to enhance the anti-icing property through fabricating a very hydrophobic surface. TiO2 was firstly modified with 3-methacryloxypropyl-trimethoxysilane (MPS) to introduce CC bonds. Then, dodecafluoroheptyl methacrylate (DFHMA) monomers were successfully grafted on the TiO2 particles via CC bonds introduced by MPS. Herein, azobisisobutyronitrile (AIBN) was used as initiator to initiate the reaction. The chemical components of the TiO2 particles were investigated by X-ray photoelectron spectroscopy (XPS). XPS analysis of fluorine-modified TiO2 revealed that the fluorine content reached a peak value of 7.3%, while the water contact angle enhanced to a maximum value of 146°. This water contact angle value of 146° was dramatically increased by 131° in comparison with unmodified TiO2, indicating a very hydrophobic surface. The crystallization temperature of a water droplet on the corresponding fluorine-modified TiO2 decreased to −19.4 °C (10.3 °C decrease in comparison with that of a water droplet on unmodified TiO2). Also, the freezing delay time on the fluorine-modified TiO2 is more than 25 min under the testing temperature of −10 °C, exhibiting excellent anti-icing property.

Understanding the anti-icing property of nanostructured superhydrophobic aluminum surface during glaze ice accretion

Ice accumulation on power transmission lines has been a vital problem for power systems in cold regions. In this paper, the anti-icing property of the as-prepared superhydrophobic (SHP) surface on the aluminum substrate in glaze ice was studied in an artificial climate chamber. Results show that the as-prepared SHP surface demonstrates excellent anti-icing property with only 24.65% of the entire surface froze after spraying for 60 min. The nano-scale structures and the HDTMS molecule both contributed to the superhydrophobicity. The reason for the excellent anti-icing property of the as-prepared SHP surface can be ascribed to two reasons: on the one hand, the nanoscale structures can effectively help maintain the superhydrophobicity of the as-prepared SHP surface at low temperatures, which inhibited the frosting process for over 210 min at −5°C and −10 °C. On the other hand, the as-prepared SHP surface can completely repel the impacting millimeter-level cooled water droplets or reducing the critical diameter of micro-scale droplets in glaze ice leading to a reduction of ice accumulation. The nanostructured ZnO textures significantly helped improve the ability to resist frost and ice accumulation on the aluminum surface, which has a good prospect on power transmission lines against ice formation.

Fabrication of slippery Zn surface with improved water-impellent, condensation and anti-icing properties

Zinc and its alloys are valuable crucial materials applied in the fields of automobile, ship manufacturing and construction industries. However, their application is limited due to poor performance on water-resistance, condensation and anti-icing property. Slippery liquid-infused porous surface (SLIPS) has been widely used owing to excellent water-repellent, condensation and anti-icing properties. In this work, a SLIPS was fabricated based on zinc substrate by using electrochemical etching, low surface energy modification and lubricant infusion, successively. According to the SEM morphologies and EDS images, it could be confirmed that the rough porous surface structure, low surface energy modification and infused lubricants are key factors accounting for the excellent anti-wetting property of fabricated slippery Zn surface. The experimental results showed that the SLIPS on zinc substrate exhibited outstanding water-repellent performance at a wide range of temperature and drop impact velocity. Moreover, its anti-wetting ability can be sustained even under the impacts of droplets or the continuous water jet. Owing to its dropwise condensation strategy, the SLIPS shows reasonable water collection efficiency, which exceeds 60 mg/(cm2·h) at relative humidity of 90%. The excellent anti-icing property is demonstrated by the simulated ice rain test and deicing force test. And the results showed that only tiny residue ice left on the SLIPS and the deicing force was 2–3 times smaller than ordinary surface. The prepared SLIPS is expected to be an adaptable and efficient method for enhancing the water-repellent, condensation and anti-icing properties of zinc substrate, and may expand the application in energy-efficient fluid handing & transportation, medicine and anti-fouling operating in low temperature environment.

Green and timesaving fabrication of a superhydrophobic surface and its application to anti-icing, self-cleaning and oil-water separation

A timesaving method based on inexpensive and nontoxic chemicals is adopted to fabricate a superhydrophobic surface for engineering applications. The characterization of chemical compositions and microstructures indicates that this superhydrophobic surface is achieved successfully by the chemical etching and stearic acid modification. This method is applicable to a surface with super hydrophobicity for many metal materials. It is important to note that the ultra-hydrophobic aluminum surface is of good bounce dynamics for different sizes of a water droplet. The water contact & sliding angle are 155° and 1° respectively on the prepared superhydrophobic surface. As expected, the sliding angle of below 1° is the key to obtain excellent anti-icing property on a superhydrophobic surface. Water droplets are prone to roll off the superhydrophobic surface, leading to the freezing delay and self-cleaning performance for different types of pollutions. In addition, the fabricated surface displays the superhydrophobic and lipophilic properties, which provide a potential application to oil-water separation.

Multi-functional application of oil-infused slippery Al surface: from anti-icing to corrosion resistance

Slippery liquid-infused porous surface (SLIPS) inspired by Nepenthes pitcher has attracted considerable attention owing to its great potential applications in icy or corrosive conditions. However, observing both anti-icing property and corrosion resistance of SLIPS has rarely reported before. In this paper, a simple approach was proposed to prepare SLIPS to protect metal from freezing rain and corrosion. The Al substrate was first electrochemically etched and anodized to construct hierarchical porous structures composed of AlOOH and Al2O3. After lowering the surface energy and infusing silicone oil, the SLIPS was obtained showing a water roll-off angle of 3°, which could exclude almost all liquids at an inclining angle of 5°. Comparative tests including freezing rain and corrosion in NaCl solution, were conducted on bare Al and prepared oil-infused slippery surface, demonstrating the excellent anti-icing and corrosion resistance properties of our SLIPS. Additionally, self-cleaning test was also successfully performed. So, this slippery Al surface with multiple outstanding properties would be useful for the anti-icing and corrosion resistance applications in extreme environment.

Superhydrophobic carbon nanotubes/epoxy nanocomposite coating by facile one-step spraying

A new superhydrophobic nanocomposite coating was prepared by combining the bisphenol A diglycidyl ether (BADGE) epoxy resin with unmodified multi-walled carbon nanotubes (MWCNTs). The mixture solutions were coated on the Q235 carbon steel surface through a facile and effective one-step spraying method. The highest water contact angle reached ~154° when 30% MWCNTs were added into the coating matrix. From the scanning electron microscopy (SEM) images, the superhydrophobic hierarchical microstructures were established via the agglomerated MWCNTs cured with epoxy resin. Furthermore, the as-prepared superhydrophobic nanocomposite coating with 30% MWCNTs showed excellent anti-icing property in the water-dripping and static freezing tests at the temperature of −10 °C. The superhydrophobic nanocomposite coating was endowed with an extraordinary mechanical durability, with the superhydrophobic state being retained even after 100 cycles in the tape-peeling test. From the electrochemical impedance spectroscopy (EIS) results, the low-frequency modulus first decreased due to the increasing conductivity of the coating surface, and then increased for the coating with 30% MWCNTs due to the air trapped in the superhydrophobic microstructure.