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Techniques preventing icing and ice accumulation on surfaces are required to solve snow- and ice-induced accidents and disasters. Recently, hydrophilic polymers have attracted attention as a passive anti-icing method. This study examined the ice-adhesion properties of the hydrophilic poly[poly(ethylene glycol) methyl ether methacrylate] (PPEGMA) concentrated polymer brush (CPB). A custom-built apparatus was developed to obtain the ice-adhesion strength and visualize the dynamics of the ice-adhesion interface under tangential loading. The ice-adhesion interface for a PPEGMA-CPB-coated glass substrate was investigated by comparing it with the bare glass substrate. As a result, the CPB exhibited a low ice-adhesion strength of less than 100 kPa, the dependencies of which on the drive speed and temperature indicate a high-viscous liquid-like layer at the interface, even below the melting point of water, leading to the smooth onset of sliding due to its self-lubricity without any rupture events (including precursory events) observed for the bare glass. [ABSTRACT FROM AUTHOR]

Icing negatively impacts various industrial sectors and daily life, often leading to severe safety problems and substantial economic losses. In this work, a fluorinated resin coating with embedded graphene nanoflakes is prepared using a spin‐coating curing process. The results shows that the ice adhesion strength is reduced by ≈97.0% compared to the mirrored aluminum plate, and the icing time is delayed by a factor of 46.3 under simulated solar radiation power of 96 mW cm−2 (1 sun) at an ambient temperature of −15 °C. The superior anti/de‐icing properties of the coating are mainly attributed to the synergistic effect of the fluorinated resin with a low surface energy, the rough structure of the sandblasted aluminum plate, which reduces the contact area, and the embedded graphene nanoflakes with a superior photothermal effect. Furthermore, the hydrogen bonding competition effect between the exposed‐edge oxygen‐containing functional groups of the embedded graphene nanoflakes and water molecules further improves the anti‐icing properties. This work proposes a facile preparation method to prepare coatings with excellent anti/de‐icing properties, offering significant potential for large‐scale engineering applications. [ABSTRACT FROM AUTHOR]

A nature-inspired approach was employed through the development of dopamine-modified epoxy coating for anti-icing applications. The strong affinity of dopamine's catechol groups for hydrogen bonding with water molecules at the ice/coating interface was utilized to induce an aqueous quasi-liquid layer (QLL) on the surface of the icephobic coatings, thereby reducing their ice adhesion strength. Epoxy resin modification was studied by attenuated total reflectance infrared spectroscopy (ATR-FTIR) and nuclear magnetic resonance spectroscopy (NMR). The surface and mechanical properties of the prepared coatings were studied by different characterization techniques. Low-temperature ATR-FTIR was employed to study the presence of QLL on the coating's surface. Moreover, the freezing delay time and temperature of water droplets on the coatings were evaluated along with push-off and centrifuge ice adhesion strength to evaluate their icephobic properties. The surface of dopamine-modified epoxy coating presented enhanced hydrophilicity and QLL formation, addressed as the main reason for its remarkable icephobicity. The results demonstrated the potential of dopamine-modified epoxy resin as an effective binder for icephobic coatings, offering notable ice nucleation delay time (1316 s) and temperature (−19.7 °C), reduced ice adhesion strength (less than 40 kPa), and an ice adhesion reduction factor of 7.2 compared to the unmodified coating. [ABSTRACT FROM AUTHOR]

ABSTRACTIt is of great significance to grasp the role of surface topography in de-icing, which however remains unclear yet. Herein, four textured surfaces are developed by regulating surface topography while keeping surface chemistry and material constituents same. Specifically, nano-textures are maintained and micro-textures are gradually enlarged. The resultant ice adhesion strength is proportional to a topography parameter, i.e. areal fraction of the micro-textures, owing to the localized bonding strengthening, which is verified by ice detachment simulation using finite element method. Moreover, the decisive topography parameter is demonstrated to be determined by the interfacial strength distribution between ice and test surface. Such parameters vary from paper to paper due to different interfacial strength distributions corresponding to respective situations. Furthermore, since hydrophobic and de-icing performance may rely on different topography parameters, there is no certain relationship between hydrophobicity and de-icing.

The food industry is a dynamic component of the European economy. A wide variety of products and small batch are demanded in a market that is accustomed to frequenting changes in food packaging formats. Cheaper and lighter 3D-printed tools are replacing expensive metallic ones, producing previously impossible product geometries and processing fish and meat products more quickly and in more reliable ways. In addition to food contact, these printed parts are often required to have hydrophobic surfaces that facilitate cleaning and have low adhesion both foodstuffs and ice. In this study, the surface wettability of PolyEthylene Terephthalate Glycol (PETG) printed parts via fused filament fabrication is assessed. Specifically, several printing parameters (layer height, extrusion temperature, printing speed, acceleration, and flow) and their influence on the hydrophobicity of 3D printed parts with vertical orientation are analyzed. The experimental results indicated that the parameter with the strongest influence on the wettability of the XZ parts was flow: low-flow values generated ultra-hydrophobic surfaces, with contact angles higher than 120°. Acceleration had no influence at low flow values; however, for high flow values, low acceleration rates yielded higher contact angles. In addition, it was experimentally proven that the 3D-printed PETG parts with high-contact angle surfaces showed lower adhesion to ice than those with low contact-angle surfaces. The technology was applied to a case study of a 3D-printed hopper for the ice duct of an ice-cube machine. [ABSTRACT FROM AUTHOR]

The quasi-liquid layer (QLL), a microstructure located between ice and an adhering substrate, is critical in generating capillary pressure, which in turn influences ice adhesion behavior. This study employed molecular dynamics (MD) methods to obtain QLL thickness and utilized these measurements to estimate the adhesive strength between ice and asphalt. The research involved constructing an ice–QLL–asphalt MD model, encompassing four asphalt types and five temperature ranges from 250 K to 270 K. The QLL thickness was determined for various asphalts and temperatures using the tetrahedral order parameter gradient. Additionally, capillary pressure was calculated based on the QLL thickness and other geometric parameters obtained from the MD analysis. These findings were then compared with ice adhesion strength data acquired from pull-off tests. The results indicate that QLL thickness varies with different asphalt types and increases with temperature. At a constant temperature, the QLL thickness decreases in the order of the basal plane, primary prism plane, and secondary prism plane. Furthermore, the adhesion strength of the QLL diminishes as the temperature rises, attributed to the disruption of hydrogen bonds at lower temperatures. The greater the polarity of the asphalt's interface molecules, the stronger the adhesion strength and binding free energy. The MD simulations of the asphalt–ice interface offer insights into the atomic-scale adhesive properties of this interface, contributing to the enhancement in QLL property prediction and calibration at larger scales. [ABSTRACT FROM AUTHOR]

Ice adhesion tests are widely used to assess the performance of potential icephobic surfaces and coatings. A great variety of test designs have been developed and used over the past decades due to the lack of formal standards for these types of tests. In many cases, the aim of the research was not only to determine ice adhesion values, but also to understand the key surface properties correlated to low ice adhesion surfaces. Data from different measurement techniques had low correspondence between the results: Values varied by orders of magnitude and showed different relative relationships to one another. This study sought to provide a broad comparison of ice adhesion testing approaches by conducting different ice adhesion tests with identical test surfaces. A total of 15 test facilities participated in this round-robin study, and the results of 13 partners are summarized in this paper. For the test series, ice types (impact and static) as well as test parameters were harmonized to minimize the deviations between the test setups. Our findings are presented in this paper, and the ice- and test-specific results are discussed. This study can improve our understanding of test results and support the standardization process for ice adhesion strength measurements. [ABSTRACT FROM AUTHOR]

Ice accretion has detrimental effects on a wide range of sensitive engineering structures, especially those adjacent to or within the ocean. Here the effect of salinity on the adhesion of ice to different surfaces is investigated over a range of sub‐zero temperatures. The saline ice adhesion strength is found to decrease with the increasing salinity on all surfaces tested. The presence of thermodynamically stable brine at temperatures above −21.2 °C is found to drastically lower the saline ice adhesion strength of essentially all surfaces through a lubrication effect. At −25 °C, below the eutectic temperature between H2O ice and hydrohalite (NaCl 2H2O), high adhesion is observed. For smooth surfaces, hydrophobicity is effective at lowering the saline ice adhesion strength, and a hydrophobic silicon wafer exhibited a saline ice adhesion strength of 2.4 ± 1.8 kPa at −10 °C with 1 wt% NaCl. The adhesion of real frozen seawater differed from the NaCl solutions, where an adhesion strength ≈12 kPa is observed even at −25 °C. Given the strong adhesion of ice to marine infrastructure, the results here demonstrate how temperature, salinity, and surface characteristics must be considered when designing materials that can mitigate the icing of marine infrastructure and vessels. [ABSTRACT FROM AUTHOR]

A nature-inspired approach was employed through the development of dopamine-modified epoxy coating for anti-icing applications. The strong affinity of dopamine’s catechol groups for hydrogen bonding with water molecules at the ice/coating interface was utilized to induce an aqueous quasi-liquid layer (QLL) on the surface of the icephobic coatings, thereby reducing their ice adhesion strength. Epoxy resin modification was studied by attenuated total reflectance infrared spectroscopy (ATR-FTIR) and nuclear magnetic resonance spectroscopy (NMR). The surface and mechanical properties of the prepared coatings were studied by different characterization techniques. Low-temperature ATR-FTIR was employed to study the presence of QLL on the coating’s surface. Moreover, the freezing delay time and temperature of water droplets on the coatings were evaluated along with push-off and centrifuge ice adhesion strength to evaluate their icephobic properties. The surface of dopamine-modified epoxy coating presented enhanced hydrophilicity and QLL formation, addressed as the main reason for its remarkable icephobicity. The results demonstrated the potential of dopamine-modified epoxy resin as an effective binder for icephobic coatings, offering notable ice nucleation delay time (1316 s) and temperature (−19.7 °C), reduced ice adhesion strength (less than 40 kPa), and an ice adhesion reduction factor of 7.2 compared to the unmodified coating.

Abstract Ice accretion has detrimental effects on a wide range of sensitive engineering structures, especially those adjacent to or within the ocean. Here the effect of salinity on the adhesion of ice to different surfaces is investigated over a range of sub‐zero temperatures. The saline ice adhesion strength is found to decrease with the increasing salinity on all surfaces tested. The presence of thermodynamically stable brine at temperatures above −21.2 °C is found to drastically lower the saline ice adhesion strength of essentially all surfaces through a lubrication effect. At −25 °C, below the eutectic temperature between H2O ice and hydrohalite (NaCl 2H2O), high adhesion is observed. For smooth surfaces, hydrophobicity is effective at lowering the saline ice adhesion strength, and a hydrophobic silicon wafer exhibited a saline ice adhesion strength of 2.4 ± 1.8 kPa at −10 °C with 1 wt% NaCl. The adhesion of real frozen seawater differed from the NaCl solutions, where an adhesion strength ≈12 kPa is observed even at −25 °C. Given the strong adhesion of ice to marine infrastructure, the results here demonstrate how temperature, salinity, and surface characteristics must be considered when designing materials that can mitigate the icing of marine infrastructure and vessels.

The most popular topcoat in the coatings industry, polyurethane (PU), still lacks an understanding of ice‐related phenomena and hence achieving an icephobic PU‐based coating has remained an important unresolved issue. This work presents fresh perspectives on how factors including chemical characteristics, cross‐link density, and mechanical characterization impact the anti‐icing capabilities and ice‐adhesion of PU coatings. In this regard, the effects of the of aforementioned coatings having various crosslink densities on wettability, ice formation, and ice adhesion were assessed via multiple approaches. Two acrylic polyols with different hydroxyl content and two commonly used aliphatic polyisocyanates with different %NCOs were utilized to fabricate the PU coatings. In addition, coatings were designed with different stoichiometric ratios providing a route to various crosslink densities and mechanical properties. Wettability characteristics were investigated using water contact angle, contact angle hysteresis, and sliding angle. The roles of urethane linkages and hydrogen‐bond formation between water molecules and urethane composition of PU coatings on ice nucleation and ice adhesion were studied through DSC, push‐off, and centrifugal tests. Mechanical characteristics and surface roughness of the coatings were investigated by tensile test and optical profilometer, respectively. [ABSTRACT FROM AUTHOR]

Ice buildup can significantly and negatively impact system performance in various industrial sectors, and has remained a persistent challenge for decades. Many compliant materials exhibit excellent de‐icing performance but are easily eroded by impacts from supercooled water droplets, sand, dust, and debris. A composite panel inspired by animal skin, consisting of a facesheet protecting a nanofluid layer beneath, which exhibits durable anti‐icing and tunable photothermal properties is proposed. The viscous liquid layer beneath the facesheet increases flexural rigidity, preventing large deflections and increasing deformation resistance, which alters ice's adhesion to the surface. The non‐uniform fluid pressure exerted by the viscous nanofluid‐filled composite panels facilitates ice detachment, resulting in ice adhesion strengths as low as τice ≈ 10 kPa. Further, by altering the fluid properties, different additional functionalities can be endowed to the system. Incorporating fumed silica in a fluid‐filled composite panel results in rheopectic behavior, and this doubles their impact resistance when the shear thickening properties are properly tuned. Additionally, the combination of a transparent facesheet and a solar light absorbent nanofluid allows for tunable photothermal properties, further enhancing the anti‐icing performance of the system. This durable and tunable nanofluid‐filled composite panel shows great promise as a multifunctional de‐icing material. [ABSTRACT FROM AUTHOR]

[Display omitted] When ice accumulates on a surface, it can adversely impact functionality and safety of a platform in infrastructure, transportation, and energy sectors. Despite several attempts to model the ice adhesion strength on ice-shedding materials, none have been able to justify variation in the ice adhesion strength measured by various laboratories on a simple bare substrate. This is primarily due to the fact that the effect of underlying substrate of an ice-shedding material has been entirely neglected. Here, we establish a comprehensive predictive model for ice adhesion using the shear force method on a multi-layered material. The model considers both shear resistance of the material and shear stress transfer to the underlying substrate. We conducted experiments to validate the model predictions on the effect of coating and substrate properties on the ice adhesion. The model reveals the importance of the underlying substrate of a coating on ice adhesion. Most importantly, the correlation between the ice adhesion and the coating thickness are entirely different for elastomeric and non-elastomeric materials. This model justifies different measured ice adhesion across various laboratories on the same material and elucidates how one could achieve both low ice adhesion and high mechanical durability. Such predictive model and understanding provides a rich platform to guide the future material innovation with minimal adhesion to the ice. [ABSTRACT FROM AUTHOR]

Ice protection techniques have attracted significant interest, notably in aerospace and wind energy applications. However, the current solutions are mostly costly and inconvenient due to energy-intensive and environmental concerns. One of the appealing strategies is the use of passive icephobicity, in the form of coatings, which is induced by means of several material strategies, such as hydrophobicity, surface texturing, surface elasticity, and the physical infusion of ice-depressing liquids, etc. In this review, surface-roughness-related icephobicity is critically discussed to understand the challenges and the role of roughness, especially on superhydrophobic surfaces. Surface roughness as an intrinsic, independent surface property for anti-icing and de-icing performance is also debated, and their interdependence is explained using the related physical mechanisms and thermodynamics of ice nucleation. Furthermore, the role of surface roughness in the case of elastomeric or low-modulus polymeric coatings, which typically instigate an easy release of ice, is examined. In addition to material-centric approaches, the influence of surface roughness in de-icing evaluation is also explored, and a comparative assessment is conducted to understand the testing sensitivity to various surface characteristics. This review exemplifies that surface roughness plays a crucial role in incorporating and maintaining icephobic performance and is intrinsically interlinked with other surface-induced icephobicity strategies, including superhydrophobicity and elastomeric surfaces. Furthermore, the de-icing evaluation methods also appear to be roughness sensitive in a certain range, indicating a dominant role of mechanically interlocked ice. [ABSTRACT FROM AUTHOR]

Recently, the photovoltaic technology has become very popular as a means to produce renewable energy. One of the problems that are still unsolved in this area of the industry is that photovoltaic panels are subject to a significant loss of efficiency due to the accumulation of dust and dirt. In addition, during the winter season, the accumulation of snow and ice also reduces or stops the energy production. The current methods of dealing with this problem are inefficient and pollute the environment. One way with high potential to prevent the build-up of dirt and ice is to use transparent coatings with self-cleaning and icephobic properties. In this work, the chemical modification of an epoxy–silicone hybrid resin using dually functionalized polysiloxanes was carried out. The icephobic properties (ice adhesion and freezing delay time of water droplets), hydrophobic properties (water contact angle, contact angle hysteresis, and roll-off angle), average surface roughness, and optical properties were characterized. It can be concluded that the performed chemical modification resulted in a significant improvement of the icephobic properties of the investigated coatings: ice adhesion decreased by 69%, and the freezing delay time increased by 17 times compared to those of the unmodified sample. The polysiloxanes also caused a significant reduction in the contact angle hysteresis and roll-off angle. The chemical modifications did not negatively affect the optical properties of the coatings, which is a key requirement for photovoltaic applications. [ABSTRACT FROM AUTHOR]

Ice formation affects the performance of many industrial components, including aircraft wings, spacecraft, and power transmission cables. In particular, ice build-up on airplane components increases drag and fuel consumption. A large number of studies have been carried out to reduce ice adhesion by developing passive methods such as icephobic coatings and active ice removal approaches such as mechanical vibrations or chemical-based solutions. Despite remarkable recent breakthroughs in the fabrication of icephobic coatings, passive ice removal solutions require higher durability to resist cyclical mechanical ice detachment treatments. Functionalized TiO2 coatings, applied using the suspension plasma spray (SPS) technique, have been shown to be robust and to have dual-scale characteristics in an ice accretion analysis. In this study, the icephobicity and mechanical durability of a novel duplex coating consisting of polytetrafluoroethylene (PTFE) solid lubricant films on TiO2-coated substrates were evaluated. Notably, various amounts of PTFE were applied on top of the TiO2 coating to identify the ideal quantity required to obtain optimal icephobic properties. Ice was generated in an icing wind tunnel, and the amount of accreted ice was evaluated to assess the anti-icing properties. Wettability parameters, including static water contact angle and contact angle hysteresis, were measured to determine the water mobility and surface energy. Ice shear adhesion to the PTFE-TiO2 duplex coating was measured using a custom-built test rig. The mechanical durability was assessed by measuring the ice shear strength for almost twenty icing–deicing cycles, and after five cycles, the roughness parameters and images taken from the surface of the samples were compared. The combination of PTFE solid lubricant film and TiO2 coating reduced ice adhesion by 70%–90% compared to that of a bare aluminum substrate (reference material). Additionally, the results showed that the application of a uniform layer of PTFE solid lubricant film on dual-scale TiO2 coating significantly reduced ice adhesion and maintained mechanical durability for 25 deicing cycles, making this combination a promising candidate for deicing approaches. [ABSTRACT FROM AUTHOR]

Accurate measurement of the interfacial shear strength between ice and solid surface has important reference significance for the design of anti-icing and de-icing functional surfaces. In this paper, a new method is proposed based on the shear lag model of a single fiber pulled out from matrix, in order to accurately determine the interfacial shear strength (ISS) between ice and metals. The maximum pull-out force at the initiation of interface debonding is well measured in the pull-out test of a metal fiber embedded in an ice matrix. A shear lag model similar to the pull-out test is established and a closed-form relation between the non-uniform interfacial shear stress and the pull-out force is achieved. When the pull-out force reaches its peak value, the ice/metal ISS can be consequently determined as the maximum interfacial shear stress. Such a method takes into account the stress concentration at the interface, which overcomes underestimation of ice/solid ISS based on the apparent strength in previous studies. The achieved ISS is proven to not only have good convergence, but also be independent of the size and embedded depth of metal fibers. Based on the present method, the enhancing effects of freezing temperature and surface roughness on the ice adhesion are further disclosed. The present research provides a simple and reliable approach to accurately calibrate the ice/solid ISS, which should be of important reference significance for the design and assessment of anti-icing functional surfaces. [ABSTRACT FROM AUTHOR]

The development of a durable and green icephobic coating plays a vital role in the aviation industry due to the adverse impact of ice formation on aircraft performance. The lack of study into how temperature and surface roughness impact icephobicity is the main problem with present icephobic coatings. This study aims to qualitatively evaluate the icephobicity performance of a polytetrafluoroethylene (PTFE) solid lubricant film, as an environmentally friendly solution, with a custom-built push-off test device in different icing conditions utilizing a wind tunnel. The ice-adhesion reduction factor (ARF) of the film has been assessed in comparison to a bare aluminium substrate (Al 6061). The impact of surface energy was investigated by comparing the water contact angle (WCA), the contact angle hysteresis (CAH), and the pull-off force of the PTFE solid lubricant and Al with an atomic force microscope (AFM). The results of ice shear adhesion on the PTFE solid lubricant film showed a significant reduction in the ice adhesion force at various substrate temperatures and surface roughness compared to the bare aluminium substrate. The difference in the ice adhesion between the solid lubricant and aluminium alloy was attributed to the differences in the detachment mechanism. For the PTFE-based solid lubricant, the interfacial detachment mechanism was based on the formation of interfacial blisters towards the centre of the ice. Consequently, upon continued application of the shear force, most of the energy injected would be distributed throughout the blisters, ultimately causing detachment. In the comparison of ice adhesion on PTFE solid lubricant and bare aluminium, the film showed minimal ice adhesion at −6 °C with an adhesion force of 40 N (ARF 3.41). For temperature ranges between −2 °C and −10 °C, the ice adhesion for bare aluminium was measured at roughly 150 N. [ABSTRACT FROM AUTHOR]

Since ice formation on surfaces at subzero temperatures leads to accidents, increased equipment maintenance costs, and reduced performance, multiple strategies, including superhydrophobic surfaces and coatings, have been explored as means to reduce ice adhesion to solid surfaces. Previous work has correlated the effect of topography of regularly patterned superhydrophobic surfaces with ice adhesion. This work, however, investigated the effect of filtered topography on ice adhesion for random superhydrophobic surfaces. The ice adhesion behavior of superhydrophobic composite coatings, prepared from a mixture of silica nanoparticles and polymer binder and sprayed on glass slides, was determined using a shear strength measurement. The ice adhesion significantly decreased with an increase in particle content up to 40 wt.%, after which the ice adhesion became nearly constant. The present study focuses on the use of a novel filtering method for coating topography evaluation which isolated the asperities contributing to the interface from the roughness profile in the superhydrophobic coating. It showed that the ice adhesion correlated with the filtered asperity height and spacing for these random hydrophobic surfaces. Higher particle contents led to larger asperity distances, smaller solid fractions, and lower ice adhesion. The results and conclusions are based on a static ice adhesion test using still water. In this work, it is demonstrated that ice adhesion can be predicted based on the solid–water–air interface, a correlation that could guide future superhydrophobic coating fabrication to create surfaces with greater reduction in ice adhesion. [ABSTRACT FROM AUTHOR]

Ice nucleation and accretion on structural surfaces are sources of major safety and operational concerns in many industries including aviation and renewable energy. Common methods for tackling these are active ones such as heating, ultrasound, and chemicals or passive ones such as surface coatings. In this study, we explored the ice adhesion properties of slippery coated substrates by measuring the shear forces required to remove a glaze ice block on the coated substrates. Among the studied nanostructured and nanoscale surfaces [i.e., a superhydrophobic coating, a fluoropolymer coating, and a polydimethylsiloxane (PDMS) chain coating], the slippery omniphobic covalently attached liquid (SOCAL) surface with its flexible polymer brushes and liquid-like structure significantly reduced the ice adhesion on both glass and silicon surfaces. Further studies of the SOCAL coating on roughened substrates also demonstrated its low ice adhesion. The reduction in ice adhesion is attributed to the flexible nature of the brush-like structures of PDMS chains, allowing ice to detach easily. HIGHLIGHTS: • Introduces several simple and reproducible techniques to reduce ice adhesion significantly on surfaces with one surface coating and identifies the coating with the lowest adhesion. • Explores the lowest-adhesion coating on surfaces with microscale and macroscale structures and finds a continued reduction in ice adhesion. • Explores qualitatively and quantitatively through surface morphology and an analytical model the results of the ice adhesion values obtained, giving justification for all such results. [ABSTRACT FROM AUTHOR]

Ice adhesion tests are widely used to assess the performance of potential icephobic surfaces and coatings. A great variety of test designs have been developed and used over the past decades due to the lack of formal standards for these types of tests. In many cases, the aim of the research was not only to determine ice adhesion values, but also to understand the key surface properties correlated to low ice adhesion surfaces. Data from different measurement techniques had low correspondence between the results: Values varied by orders of magnitude and showed different relative relationships to one another. This study sought to provide a broad comparison of ice adhesion testing approaches by conducting different ice adhesion tests with identical test surfaces. A total of 15 test facilities participated in this round-robin study, and the results of 13 partners are summarized in this paper. For the test series, ice types (impact and static) as well as test parameters were harmonized to minimize the deviations between the test setups. Our findings are presented in this paper, and the ice- and test-specific results are discussed. This study can improve our understanding of test results and support the standardization process for ice adhesion strength measurements.

Superhydrophobic surfaces fabricated by grafting 1H,1H,2H,2H-heptadecafluorodecyl trimethoxysilane (FD-TMS) and polydimethylsiloxane triethoxysilane (PDMS-TES) onto a nano-micro hierarchical aluminum (Al) surface are considered to possess substantial anti-icing functionality, with delayed freezing and low ice-adhesion strength (IAS). Verifying the impacts of PDMS and the synergism of PDMS and FD on the anti-icing performance is the goal of this study. Roughness, one of the prerequisites for superhydrophobicity, was obtained by etching Al substrates in aqueous HCl, followed by immersion in boiling water. FD-TMS and PDMS-TES were then coated on the rough Al substrates layer by layer; a congener coated with a single layer was also prepared for comparison. The FD-PDMS1.92 (1.92 wt.%) coating, in which FD-TMS and PDMS-TES were used as primary and secondary coating materials, respectively, exhibited superior icephobicity, with the lowest IAS of 28 kPa under extremely condensing weather conditions (−20 °C and 70% relative humidity, RH) and the longest freezing delay time of 230 min (at −18 °C). These features are attributed to the incorporation of a dense coating layer with a low-surface-tension FD and the high mobility of PDMS, which lowered the contact area and interaction between the ice and substrate. The substrate coated with FD-PDMS1.92 exhibited improved durability with an IAS of 63 kPa after 40 icing/melting cycles, which is far less than that achieved with the FD single-layer coating. [ABSTRACT FROM AUTHOR]

Ice accumulation on atmospheric structures will result not only in inconvenience to human activities, but also various catastrophic events. Many anti-icing coatings have been developed for anti-ice accretion on various atmospheric structures. However, such mitigating icing performances and developments in practical applications are restricted by various factors. Therefore, current mitigating icing coatings are far from practical implementation. Rough and smooth hydrophobic coatings have demonstrated their potential for mitigating ice formation. To advance the development of mitigating icing coatings, a perspective of hydrophobic coatings for mitigating icing is in need. Herein, this paper categorizes the mitigating icing coatings by their wettability firstly. Then, we recap the state-of-the-art hydrophobic coatings for mitigating icing. Afterwards, we point out the deficiency and limitations of current coatings for anti-icing. At last, we provide a perspective of future trends and development directions. This perspective review can guide the design of mitigating icing coatings towards practical implementation. [ABSTRACT FROM AUTHOR]

Synthetic surfaces engineered to regulate phase transitions of matter and exercise control over its undesired accrual (liquid or solid) play a pivotal role in diverse industrial applications. Over the years, the design of repellant surfaces has transitioned from solely modifying the surface texture and chemistry to identifying novel material systems. In this study, selection criteria are established to identify bio‐friendly phase change materials (PCMs) from an extensive library of vegetable‐based/organic/essential oils that can thermally respond by harnessing the latent heat released during condensation and thereby delaying ice/frost formation in the very frigid ambient that is detrimental to its functionality. Concurrently, a comprehensive investigation is conducted to elucidate the relation between microscale heat transport phenomena during condensation and the resulting macroscopic effects (e.g., delayed droplet freezing) on various solidified PCMs as a function of their inherent thermo‐mechanical properties. In addition, to freeze protection, many properties that are responsive to the thermal reflex of the surface, such as the ability to dynamically tune optical transparency, moisture harvesting, ice shedding, and quick in‐field repairability, are achievable, resulting in the development of protective coatings capable of spanning a wide range of functionalities and thereby having a distinctive edge over conventional solutions. [ABSTRACT FROM AUTHOR]

Anti-icing coatings have provided a very good alternative to current, uneconomic, active deicing methods, and their use would bring a number of significant benefits to many industries, such as aviation and energy. Some of the most promising icephobic surfaces are those with hydrophobic properties. However, the relationship between hydrophobicity and low ice adhesion is not yet clearly defined. In this work, chemical modification of an epoxy gelcoat with chemical modifiers from the group of double organofunctionalized polysiloxanes (generally called multifunctionalized organosilicon compounds (MFSCs)) was applied. The anti-icing properties of manufactured coatings were determined by means of measurements of shear strength between the ice layer and the modified surface, conducted using a tensile machine. In the work, tests were also performed on the roughness, wettability, and durability of the properties in an aging chamber. It was found that the performed modifications of the coating's chemical composition by the addition of polysiloxanes enabled us to reduce ice adhesion by 51% and to increase the water contact angle by 14% in comparison to the neat gelcoat. A reduction in ice adhesion was also observed with the increasing water contact angle and with decreasing surface roughness. In addition, only one modification recorded an increase in ice adhesion after exposure in the aging chamber. [ABSTRACT FROM AUTHOR]

Understanding the ice adhesion mechanism is vital for efficient anti-icing. However, previous studies focused on the adhesion of already sintered ice-solid contacts. Here, we study the adhesion mechanism between preformed ice and solid surfaces. In particular, we investigate the initial stages of ice adhesion. We find that capillary bridges formed by the quasi-liquid layer on the ice surface enhance ice adhesion. The adhesion force showed a maximum around −2 °C. Our model indicates that the nano-scaled curvature of the capillary bridge gives rise to strong adhesion forces in the temperatures between −5 and 0 °C. The capillary bridge expands and consolidates over time, causing an increase of adhesion force. These findings provide new physical insights into the ice adhesion mechanism with strong implications to the development of water-repellent superhydrophobic coatings for efficient anti-icing of solid surfaces. [ABSTRACT FROM AUTHOR]

We provide a conceptual framework to correctly measure both ice adhesion strength and interfacial toughness, using a simple push test method, for a complete and comprehensive assessment of ice adhesion on surfaces. [Display omitted] • The ice-substrate fracture mechanism can be stress- or toughness-dominated. • A novel conceptual framework for ice adhesion measurements is provided. • Interfacial toughness measurement procedure based on simple push test is proposed. The interest in the development of icephobic surfaces has pushed towards the definition of standardized processes and parameters to assess ice adhesion, with the ambition of identifying an equivalent method to contact angle measurements used to assess wetting properties. Although most studies focus on the average ice adhesion strength, measured as the force per unit area required to detach ice, much less attention is paid to interfacial toughness, perhaps as its measurement is challenging. In this article, we provide a conceptual framework to correctly measure both ice adhesion strength and interfacial toughness, even using a simple push test method, laying the ground for a complete and comprehensive assessment of surface icephobicity. [ABSTRACT FROM AUTHOR]

[Display omitted] • A strategy to solve the challenge of liquid loss in SLIPS coatings was proposed. • POG-PDMS-EM-12 %@MXene coating had an ultra-low ice adhesion strength (∼4.66 kPa) and consistently maintained ice adhesion strength below 10 kPa for 70 days. • The coating exhibited excellent photothermal properties, with icing time delayed by a factor of 33.2 under 1 sun illumination at − 15 °C. • The ice adhered to the coating could slide off easily at an inclination angle of 11° without applying external force under "1 sun" at − 10 °C. The accumulation of ice on the surfaces of equipment/facilities can result in energy wastage, substantial economic losses, and even pose a threat to personal safety. In this work, a three-dimensional (3D) liquid-based porous resin coating doped with oleophilic molybdenum carbide (Mo 2 C) MXene nanoflakes was fabricated on a pre-coated oleogel sealer layer of aluminum plate. The results showed a reduction of approximately 99.1 % in ice adhesion strength (∼4.66 kPa) compared to the sandblasted aluminum plate and consistently maintained ice adhesion strength below 10 kPa for 70 days. Moreover, the coating exhibited excellent photothermal properties, with icing time delayed by a factor of 33.2 under simulated solar radiation power of 96 mW/cm2 (1 sun) at an ambient temperature of − 15 °C. The ice adhered to the coating could easily slide off without the external force under "1 sun" at − 10 °C. The superior anti/de-icing performance of the coating can be primarily attributed to the low interfacial modulus of the porous structure, the exceptional retention of silicone-oil, and the excellent photothermal effect of embedded MXene nanoflakes. The 3D liquid-based porous coating, possessing extremely low ice adhesion and remarkable de-icing stability, demonstrates the substantial potential for practical applications that require sustained anti/de-icing performance. [ABSTRACT FROM AUTHOR]

The combined effect of parameters like surface stiffness, topography, and interface size on ice adhesion and its interfacial fracture behavior was studied. Ice adhesion on aluminum and polyurethane with three different surface roughness and two different surface sizes was evaluated experimentally through mode II interfacial fracture tests on a previously formed block of ice. Results showed that, for stiff surfaces the surface roughness increases the adhesion significantly, due to the transition from adhesive to cohesive fracture. Compliant surfaces do not show this transition, in the same roughness scale due to its susceptibility to deformation. The force required to fracture an ice block from stiff surfaces stabilize after a certain length, while compliant surfaces do not show this transition at the length scales studied. The article elucidates the relevance of different parameters and the consideration of size scales for designing low ice adhesion surfaces. • The ice adhesion behavior on stiff and compliant surfaces is unlike. • The influence and interplay between surface topography, size and stiffness on ice adhesion is presented. • The microstructure of fractured ice surfaces that elucidate cohesive adhesive fracture is captured. [ABSTRACT FROM AUTHOR]

Ice accretion on a bare surface causes a serious problem in industries and daily life such as communication, electricity, and transportation. At present, the main de-icing method is active de-icing, which includes mechanical de-icing or electric-thermal de-icing and spraying glycol anti-icing agents. These methods have a high cost of manpower, energy, and environment. In addition, active de-icing is not applicable in many scenarios. To solve this problem, icephobic surfaces are expected to be widely used. Icephobic surfaces can be divided into surfaces that prolong the freezing time and surfaces with low ice adhesion. Anti-icing surfaces, represented by superhydrophobic surfaces, can inhibit a stable formation of ice nucleation from delaying ice formation, which enables the supercooled droplets to rebound from the surface to prevent ice formation. However, under high humidity and high atmospheric pressure, the superhydrophobic surface may lose efficiency due to frosting and other reasons. Compared with anti-icing surfaces, de-icing surfaces are more achievable. Thus, this article mainly explores surfaces with low ice adhesion. Passive de-icing mainly refers to the construction of the ice sparing surface on a bare substrate to reduce the adhesion strength of icing. Compared with active de-icing methods, the passive method has advantages of low energy consumption, low cost, and environmental friendliness. The realization of low ice adhesion is mainly related to low surface energy, interface slippage, and crack initiation. According to the realization mechanism, low ice adhesion surfaces can be divided into low surface energy surfaces, lubricated surfaces, interfacial slippage and low shear modulus surfaces, and crack initiators surfaces. The design principles and mechanism of the de-icing surface are explored and summarized in this article. In addition, to eliminate the doubts about the large variations in the reported ice adhesion strength caused by different measurement methods, the measurement standards of ice adhesion are also analyzed and discussed.

Recently, the photovoltaic technology has become very popular as a means to produce renewable energy. One of the problems that are still unsolved in this area of the industry is that photovoltaic panels are subject to a significant loss of efficiency due to the accumulation of dust and dirt. In addition, during the winter season, the accumulation of snow and ice also reduces or stops the energy production. The current methods of dealing with this problem are inefficient and pollute the environment. One way with high potential to prevent the build-up of dirt and ice is to use transparent coatings with self-cleaning and icephobic properties. In this work, the chemical modification of an epoxy–silicone hybrid resin using dually functionalized polysiloxanes was carried out. The icephobic properties (ice adhesion and freezing delay time of water droplets), hydrophobic properties (water contact angle, contact angle hysteresis, and roll-off angle), average surface roughness, and optical properties were characterized. It can be concluded that the performed chemical modification resulted in a significant improvement of the icephobic properties of the investigated coatings: ice adhesion decreased by 69%, and the freezing delay time increased by 17 times compared to those of the unmodified sample. The polysiloxanes also caused a significant reduction in the contact angle hysteresis and roll-off angle. The chemical modifications did not negatively affect the optical properties of the coatings, which is a key requirement for photovoltaic applications.

Icing and ice accretion cause severe problems in different industrial sectors, e.g., in aircrafts, aviation traffic, ships, solar panels, and wind turbines. This can lead to enormous economic losses and serious safety issues. Surface engineering can tackle these problems by designing surface structures to work as icephobic coatings and, this way, act as passive anti-icing solutions. In this research, slippery liquid-infused porous structures were fabricated using flame- and cold-spraying to produce polymer (LDPE and PEEK) coatings, and impregnated with a silicone lubricant. Microstructural details, surface properties, wetting behavior, and cyclic icing–deicing behavior were evaluated via ice adhesion measurements, which show the potential performance of SLIPS designs. All these SLIPS showed low or medium-low ice adhesion after the first icing-deicing cycle and the best candidate showed stable performance even after several icing-deicing cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] • Choline-based IL harbouring hydrophobic anion in coating exhibited superior hydrogen-bond donor ability to water. • Switching from EG to GL in DESs increased hydrogen-bonding sites, boosting anti-icing properties. • Coating containing GL-based DES reduced ice formation temperature to −36 °C and adhesion strength to 10 kPa. • Solid-state NMR validated the presence of QLL, contributing to ultra-low ice adhesion. • DESs in coatings altered frost patterns, enhancing durability against frost formation. The development of anti-icing coatings for extremely low temperatures is still emerging. Deep eutectic solvents (DESs), as subset of ionic liquid (IL) analogues, have recently gained increasing attention for their unique and versatile applications. Given no investigation regarding anti-icing capabilities of DESs, our study focused on the exciting potential of choline-based DESs. The intriguing potential of hydrogen bonding through the synergistic combination of DESs and ILs offers significant promise for innovative solutions to ice-related challenges that remain largely unexplored. We conducted a comprehensive study on the anti-freezing properties of DESs by synthesizing choline-based ILs featuring both hydrophilic and hydrophobic anions. We aimed to explore how the diverse hydrogen-bond donors in DESs combined with the synthesized ILs to enhance the system's ability to prevent ice formation. Substituting ethylene glycol (EG) with glycerol (GL) resulted in achieving an ice formation temperature of − 36 °C and an exceptionally low ice adhesion strength of 10 kPa, due to a thicker quasi-liquid layer on the coating surface, confirmed by solid-state NMR spectroscopy. The altered frost formation patterns of the DES-containing coatings demonstrated an enhance resistance against frost formation. This comprehensive study underscored the promising synergy between DESs and ILs for highly effective ice mitigation. [ABSTRACT FROM AUTHOR]

The impact of winter on exposed structures and transportation poses significant dangers and costs to various industries, particularly the transportation sector. Icephobic surfaces are currently being developed to reduce winter-related impacts. Creating such surfaces requires considering various factors, including reducing and preventing ice accumulation, significantly decreasing ice adhesion, and/or delaying water solidification. Although established methods such as centrifugal force and push-off tests exist for measuring ice adhesion, the results may not always correlate or offer the needed information for specific applications. To better assess icephobic properties, we have developed a novel device called the human motion–inspired automated apparatus (HMA) that mimics manual de-icing performed by humans in a scraping mode. The primary objective of the HMA is to emulate human removal of ice-covered surfaces, providing a more realistic evaluation of icephobic properties according to the ease of ice removal. This apparatus aims to revolutionize icephobic material assessment by offering improved accuracy, repeatability, and versatility in testing. We developed a unique procedure using low icing conditions, which are challenging to evaluate using conventional methods, and assessed four surfaces: aluminum as a reference, an epoxy-based hydrophilic coating, a hydrophobic silicone elastomer coating, and a hydrophobic epoxy–silicone coating. Our HMA characterizes surfaces according to several crucial parameters, including the normal force required to initiate ice scraping removal, the maximum force achieved, the angle of attack, and the equivalent force, all consistent with validation tests conducted by humans. Among the evaluated surfaces, the silicone coating required the lowest normal force, and the epoxy–silicone coating had the lowest maximum and equivalent forces. Our HMA results align well with validation tests conducted by humans. The HMA enables evaluating various critical icing conditions and promises a broad range of applications in research and development. • Introduction of a novel Human Motion-Inspired Automated Apparatus (HMA) to assess icephobic properties. • HMA mimics real-world human scraping actions to provide accurate and repeatable measurements. • HMA testing shows silicone and epoxy–silicone surfaces require significantly less force for de-icing compared to aluminum. • The study demonstrates improved methodologies for evaluating icephobic coatings under realistic icing conditions. [ABSTRACT FROM AUTHOR]

Here, we present liquid-infused surfaces (LISs) fabricated on an aluminum substrate using the anodizing method to introduce specific nanofeatures infiltrated by silicone oil to reduce the friction between ice and surface. To achieve various nanostructures on the aluminum substrate, the anodizing conditions are varied. The ice adhesion stress could be significantly plummeted to 21.7 kPa on an LIS with optimized dimensions for nanofeatures. Frost formation tests in environments with a relative humidity of 75 % on the fabricated surfaces with a temperature of −17 ℃ reveal that the fabricated samples can considerably extend the frost formation time. The frosting time for the fabricated sample can reach 47 min, whereas the bare aluminum is completely covered by frost only after 1.5 min [Display omitted] • Durable liquid-infused surfaces (LIS) were designed on anodized aluminum. • The anodizing states' effect on the anti-ice and anti-frost abilities was studied. • Anti-frost performance of LISs was better than the superhydrophobic surfaces. • For the optimized conditions, the frost time was raised by 3066 % on LIS. • After repeating the anti-ice tests, the ice adhesion force remained below 70 kPa. [ABSTRACT FROM AUTHOR]

Slippery liquid-infused porous surfaces (SLIPSs) are used in anti-fouling, anti-icing and anti-corrosion, but lack of long-term durability is a challenge due to lubricant depletion. SLIPS with self-lubricating properties can achieve extended durability without reapplying the lubricant. Generally, lubricant is stored close to surface, thus lubricant reservoir is limited. Here bulk of porous material acts as lubricant reservoir in 316 L stainless-steel SLIPS with self-lubricating properties for lowering ice adhesion. The reservoir was fabricated by using a space holder technique in metal injection molding (MIM) with lubricant reservoir volume up to 17.3 %. Surface was activated with vinyltrimethoxysilane (VTMS) to attract lubricant. Ice adhesion strength was increased up to three times against non-porous reference in ice adhesion testing using porous surface without lubrication. The best performing SLIPS showed 6.7 times lower ice adhesion against counterpart porous surface without lubricant and 1.7 times lower than non-porous reference. This self-lubrication was achieved on mechanically durable structure having an adjustable lubricant storage capacity by temperature-driven phenomenon during de-icing. [Display omitted] • Bulk porosity enabled lubricant storage in reservoirs. • Low ice adhesion was achieved on lubricant covered surface. • Lubricant reservoir was utilized for extended durability against depletion. • Surface porosity increased ice adhesion without lubricant. • Lubricant replenishment was achieved by temperature-driven phenomenon. [ABSTRACT FROM AUTHOR]

In recent years, to progress towards carbon emissions reduction, photovoltaic technology has become one of the most significant methods of generating electricity using renewable sources. However, the accumulation of ice and snow during the winter season affects the decrease in the power generation efficiency of photovoltaic modules. As a promising solution, coatings that exhibit anti-icing properties can be used. To date, no efficient ice-phobic coating has been developed for use on photovoltaic panels. In this paper development of transparent silicone-epoxy coatings modified with bi- and tri-functionalized octaspherosilicates was presented. The used organosilicone-based modifiers reveal both types of functional groups: one increases the surface properties and the second compatibility with the polymer matrix. The icephobic properties were discussed by determining an ice adhesion (IA) and a freezing delay time of water droplets (FDT). The coating exhibiting the highest anti-icing performance achieved the IA of 102 kPa and the FDT of 210 min, a 43 % reduction and a 70 times increase in value compared to the unmodified coating, respectively. The performed study included also the characterization of hydrophobic properties: water contact angle (WCA) at room temperature and below 0°C, contact angle hysteresis(CAH), and roll-off angle (RoA) as well as surface roughness and coatings thickness. In addition, the correlations between them and ice adhesion/freezing delay time were determined. It was found that roughness as well as dynamic parameters of the wettability of CAH and RoA have a significant effect on the obtained IA values. Moreover, the developed coatings can be potentially applied to photovoltaic panels, since the conducted modification did not affect the optical properties of the investigated coatings. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] Loss of anti-icing properties of slippery liquid-infused porous surfaces (SLIPS) in conditions of repetitive shear stresses is the intrinsic process related to peculiarities of SLIPS structure. The study of the evolution of the ice adhesion strength to superhydrophobic surfaces (SHS) and SLIPS during repetitive icing/de-icing cycles measured by a centrifugal method was supplemented with the estimation of change in capillary pressure inside the pores, and SEM analysis of the effect of multiple ice detachments on surface morphology. Obtained data indicated that although for freshly prepared SLIPS, the ice shear adhesion strength at −25 °C was several times lower than for SHS, repetitive icing-deicing cycles resulted in dramatic SLIPS degradation. In contrast, SHS showed weak degradation at least during 50 cycles. Additional to the depletion of an impregnating oil layer, other mechanisms of SLIPS degradation were hypothesized and tested. It was shown that lower capillary pressure required to displace air by water from the surface texture for SLIPSs compared to SHSs resulted in deeper water/ice penetration inside the grooves. The accelerated destruction of the mechanical texture caused by the Rehbinder effect constitutes another mechanism of SLIPSs degradation. [ABSTRACT FROM AUTHOR]

In this study, we assessed the effects of ice types, test parameters, and surface properties on measurement data of the ice adhesion centrifuge test. This method is often used for the evaluation of low ice adhesion surfaces, although no test standard has been defined yet. The aim of this paper is to improve the understanding of the relevant test parameter and identify crucial criteria to be considered in harmonization and standardization efforts. Results clearly indicate that the ice type (static vs. impact ice) has the greatest impact on the test results, with static ice delivering higher values in a broader data span. This is beneficial for material developers as it eases the evaluation process, but it contradicts the technical efforts to design tests that are as close as possible to realistic technical environments. Additionally, the selected ice type has a significant impact on the relevance of the surface properties (roughness, wettability). Despite the complexity of interactions, a trend was observed that the roughness is the determining surface parameter for high impact velocity ice (95 m/s). In contrast, for tests with static ice, the wettability of the test surface is of higher relevance, leading to the risk of overestimating the icephobic performance of structured surfaces. The results of this paper contribute to the demanding future tasks of defining well-founded test standards and support the development of icephobic surfaces. [ABSTRACT FROM AUTHOR]

[Display omitted] Ice adhesion to solids, being affected by the ice/solid intermolecular interactions and structure of ice surface layer is dependent on temperature, and ice surface layer equilibration time. A new centrifugal method of shear ice adhesion strength measurement with accurate temperature control on each stage from ice formation on test surfaces to the adhesion measurement is applied to study ice adhesion to superhydrophobic and slippery surfaces. The determinative advantage of the developed method is related to monitoring in one experiment the ice detachment from numerous samples and accurate measuring the rotation frequency for each ice detachment. The following findings will be discussed. 1. Strong temperature dependence of an ice adhesion strength to superhydrophobic and slippery surfaces. 2. A decrease in the ice adhesion strength to a rough surface during prolonged ice exposure at a given temperature. 3. The delayed spontaneous detachment of ice from the superhydrophobic surface under prolonged action of shear stresses notably lower than those leading to instantaneous detachment. 4. Fast degradation of a slippery surface with an increase in ice adhesion strength if the infusing liquid is not replenished before each measurement. [ABSTRACT FROM AUTHOR]

[Display omitted] In this work, we study the effect and evolution of frost condensation on the ice adhered micro-nano structured Ni metal surface. By measuring the ice adhesion strength to the porous-structured surface under different frosting coverage, it is found that the ice adhesion on the surface changes not only with the morphology but also with the different evolution stages of the frosting coverage. Combining the changes in surface morphology and low-temperature wettability, the reasons for the changes in the ice adhesion strength are attributed to the change of wettability of the porous-structured surface under different frosting coverage, which affects the infiltration state of the surface and results in different mechanical interlocking, air-pockets and cracks states at the ice-solid interface. Moreover, it is found that the ice adhesion strength of the hydrophobic and hydrophilic porous-structured surface tends to be the same when the surface is heavily frosted. In addition, we demonstrate that both the hydrophobic and hydrophilic columnar-structured surfaces have smaller ice adhesion strength than the original surface without any micro-nano structures regardless of whether the surface is frosted or not, and the measured lowest ice adhesion strength of the hydrophobic columnar-structured surface can be down to 30 kPa in all frosted evolution stages, which is less than one tenth of the original surface. The findings in this work suggest that the influence of frosting should be fully considered when designing the icephobic micro-nano structured metal structure, and it can further serve as an important guidance for the design of passive icephobic surfaces expected to be free from the frosting effect. [ABSTRACT FROM AUTHOR]