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To address the increased demand for greater mechanical robustness of superhydrophobic and icephobic surfaces, we fabricated damage-tolerant, abrasion-insensitive, and icephobic superhydrophobic bulk nanocomposites using a facile, cost-effective, industrially applicable, and environmentally benign strategy. We prepared nanocomposites composed of high-temperature vulcanized silicone rubber through the highly controlled incorporation of nanosized fumed silica and microsized aluminum trihydrate particles. The produced nanocomposites did not require additional processing, such as sand abrasion or plasma treatment, to acquire their superhydrophobic properties. The extended roughness throughout the whole bulk of the nanocomposites imparted the volumetric superhydrophobicity and resistance to mechanical damage. The presence of micro-nanoparticles also enhanced the thermal stability and icephobic properties of the silicone rubber. The icephobic behavior of the developed nanocomposites was assessed based on freezing delay and push-off tests both of which denoted improved icephobic properties, i.e., high freezing delay time and low ice adhesion strength. We verified the extended duration of superhydrophobicity within the bulk nanocomposite using sandpaper abrasion, severe cutter scratching, tape peeling, and water-jet impacts. This study represents the first evaluation, to the best of our knowledge, of the icephobic properties of both the surface and bulk of the produced nanocomposite subjected to several cycles of sandpaper abrasion. Interestingly, even after multiple abrasion cycles, the samples demonstrated considerably low ice adhesion strength confirming their bulk icephobicity. In a nutshell, our findings are very promising for the fabrication of mechanically robust icephobic materials.

Low-adhesive surfaces have been highlighted due to the potentials to mitigate fouling issues by preventing unwanted substances from adhering. Realizing superhydrophobicity with 3D surface structures/chemical modifiers or fabricating lubricant-assisted slippery surfaces has been demonstrated to realize low-adhesive surfaces. However, they still need to overcome the transition to Wenzel from Cassie states of droplets on 3D surface structures or the lubricant depletion issues of slippery surfaces for sustainable operations. Herein, we report the fabrication of low-adhesive polymeric surfaces, neither assisted by 3D surface structures/chemical modifiers nor lubricants, which is realized by embedding the interconnected pore networks underneath the top smooth surface using a water steaming method. The fabricated silicone surfaces exhibit low-adhesive properties due to the stress concentration effects generated by the subsurface-structured pores, favorable for easy detachment of the adherent from the surface. Our platform can be exploited to lower adhesion of superhydrophilic surfaces or to achieve ultralow-adhesive properties upon combination with superhydrophobicity. Finally, scale precipitation tests reveal 4.2 times lower scale accumulation of our low-adhesive polymeric surfaces than that in control samples.

Cold-weather penguins continually dive in and out of the water and get splashed by waves during the frigid Antarctic winter. Yet, even under these extreme sub-zero conditions, macroscopic ice crystals are typically not observed on their feathers. In this work, we hypothesize that the origin of the anti-icing properties of a cold-weather penguin’s feathers comes from a unique combination of the feather’s macroscopic structure, the nanoscale topography of its barbules, and the hydrophobicity of its preen oil. We show that, the combination of all three, make cold-weather penguin feathers both highly water repellant and icephobic. In this paper, we present the results from a series of droplet freezing experiments performed on feathers from a number of species of both cold-weather and warm-weather penguins. Compared to a smooth glass substrate, freezing was delayed by a factor of 30-times for drops deposited on warm-weather penguin feathers and 60-times for cold-weather penguins. The difference in freezing time between warm- and cold-weather penguins was statistically significant and can be attributed to the increase in the contact angle measured between the drop and the feather of the cold-weather penguin. This increased contact angle is the result of an increase in the hydrophobicity of the preen oil and the inclusion of nanoscale, air-trapping dimples on the surface of the barbules. The physics of this delay are explained through the development of a simple heat transfer model which demonstrates that increasing contact angle is a primary cause of increased freezing time and icephobicity. The results of this study can be used to motivate the designs of biomimetic surfaces to minimize ice formation in extreme conditions for a number of important engineering applications.

To explore novel coatings with potential for easy release of ice (icephobicity), a series of platinum-cured silicone coatings was prepared incorporating SYL-OFF 7210, designated MQ-R, as a nanoscale reinforcing component. These optically transparent coatings are designated according to cure temperature and MQ-R wt %, for example, Pt-PDMS(25)-20 for 25 °C cure and 20 wt % MQ-R. Surface characterization included dynamic contact angles and morphology by atomic force microscopy. Bulk characterization was accomplished with stress-strain measurements at 25 °C and dynamic mechanical analysis from -110 to 150 °C. Ice adhesion tests at -10 °C showed modulus had a dominant effect in increasing

Superhydrophobic surfaces show attractive anti-icing properties. However, it remains a challenge for them to achieve icephobicity and ultralow ice adhesion in a humid environment, which is fundamen...

The fundamental understanding of the icephobic performance of two model superhydrophobic surfaces (lotus and petal surfaces) is important for many industrial applications. The effect of wettability and surface energy on ice adhesion has recently received attention. However, the verification of icephobicity is typically carried out with a single observation method. For this study, rough modified rod-coated surfaces, structured polymer surfaces and nine smooth surfaces with tunable wettability were fabricated. Combining several observation techniques of icephobicity indicate that petal and lotus surfaces lose their superhydrophobicity, being less useful for ice repellency due to poor humidity tolerance in condensation conditions. The ice adhesion of rough surfaces enhanced with increasing hydrophobicity. The increased interface area leads to a reduction of the icephobic performance. The stress concentrator on the lotus surface was better than on the petal surface. In addition, the role of dynamic wettability on ice adhesion was checked. Smooth hydrophobic surfaces were found to be better icephobic materials compared to rough surfaces. The intrinsic surface energy of smooth surfaces is significantly linear with the ice adhesion. High freezing delay times were found for smooth low-density polyethylene resin and fluorinated surfaces.

Promising progress in the field of icephobicity has been made in the recent years. However, a majority of the reported icephobic surfaces rely on static mechanisms, and they maintain low ice adhesion on surfaces at extreme temperatures (as low as −60 °C), which is highly challenging. Dynamic anti-icing surfaces, which can melt ice or change the ice–substrate interfaces from the solid to liquid phase after the formation of ice, serve as a viable alternative. In this study, liquid layer generators (LLGs), which can release ethanol to the ice–solid interface and convert the ice–substrate contact from the solid–solid mode to the solid–liquid–solid mode, were introduced. Excellent icephobicity on surfaces with an ethanol lubricating layer was found to withstand extremely low temperatures (−60 °C), which was proven by both molecular dynamics simulations and experiments. Two prototypes of LLGs, one by packing ethanol inside and the other by storing replenishable ethanol below the substrate, were fabricated. These LLGs could constantly release ethanol for a maximum of 593 days without source replenishment. Both these prototypes exhibited super-low ice adhesion strengths of 1.0–4.6 kPa and 2.2–2.8 kPa at −18 °C. For select samples, by introducing an interfacial ethanol layer, the ice adhesion strength on the same surfaces decreased in an unprecedented manner from 709.2–760.9 kPa to 22.1–25.2 kPa at a low temperature of −60 °C.

Ice accumulation leads to improper functioning or even damages to ships, offshore platforms, sports facilities and land buildings in cold climate regions. Although fluorochemicals have demonstrated attractive performance for icephobic applications, their use has been restricted due to health and environmental concerns. Here, we present a facile method to fabricate fluorine-free icephobic coatings with potential applications for outdoor facilities and structures. The coating consists of a silicone-epoxy hybrid resin, polydimethylsiloxane (PDMS) and SiO2 nanoparticles with different sizes. Particularly, the use of different sized (10–20 nm and 200 nm) SiO2 nanoparticles results in excellent icephobicity and mechanical properties. The mechanical properties and durability of the coating were analysed according to respective test standards and compared with other reported icephobic coatings. The durable icephobic potency of the coatings is very promising as a sustainable green solution for various practical anti-icing applications. Agency for Science, Technology and Research (A*STAR) Nanyang Technological University Accepted version Financial support is gratefully acknowledged from Nanyang Technological University (NTU) in form of research student scholarship (RSS), NTU-industry collaborative funding in the form of RCA, and the Agency for Science, Technology and Research (A*STAR) of Singapore in the form of research grant (SERC 1528000048).

Anti-icing coatings reduce the freezing onset temperature for water by changing the chemical and physical environment at the water-substrate interface to prevent ice nucleation and growth. Graphene oxide has several attributes that make it attractive as an anti-icing coating and it has been theoretically predicted that graphene oxide has a lower freezing onset temperature than pristine graphene. Here, we test this hypothesis using carefully prepared, well-characterized graphene oxide substrates. We compare the water contact angle for graphene and graphene oxide coatings, both prepared on iridium(111) surfaces. The results show both materials to be transparent to wetting, but indicate a lower freezing onset temperature for graphene oxide than for pristine graphene. The measured water contact angles are dominated by the properties of the underlying Ir(111) substrate while the freezing onset temperature is dictated by the functional groups present on the graphene basal plane. We suggest that the lowering of the freezing onset temperature is caused by the formation of a viscous water layer on the surface. Scanning tunneling microscopy and x-ray photoelectron spectroscopy data are used to evaluate the robustness of the coating material and suggest ways to improve the long-term performance, namely by advancing strategies to avoid water intercalation. publishedVersion

Ice accretion on surfaces exposed to supercooled drops is a major issue in several fields, especially for aircraft. The severity and hazardousness of this phenomenon largely depends on the environmental conditions met by the surface. Currently, active ice protection systems are applied to limit the risks related to ice accretion on aircraft, but intense efforts are devoted to the development of passive ice protection systems to overcome their limitations. Anti-wetting materials have been explored as potential icephobic surfaces, with the Slippery, Liquid-Infused Porous Surfaces approach (SLIPS) being one of the most innovative and intriguing possible solutions. However, the literature lacks a proper characterization of the behavior of SLIPS in icing wind tunnel tests that simulate the different icing conditions. In our work, we report the fabrication of ceramic-based coatings as per the SLIPS approach, utilizing two different ceramic porous matrixes and several infused liquids; we also assess the ability of these coatings to reduce ice accretion in icing wind tunnel tests in both glaze and rime icing regimes, as well as their properties in terms of reduced ice adhesion. Observing the remarkable icephobic behavior displayed by these materials in both types of tests, SLIPS gain significant consideration as candidate passive ice protection systems for aeronautical applications.

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.

There has been increasing interest in recent years in identifying an ice-removal procedure that is low cost and scalable and consumes a negligible amount of energy in order to prevent catastrophic failures in outdoor structures. One of the potential solutions to the structural problems caused by frigid and icy conditions is the use of slippery liquid-infused porous surfaces (SLIPS) to effect passive ice removal using easy, economical, and energy-free means. This work takes advantage of the highly flexible layer-by-layer (LbL) technology to customize and design surfaces that have a high degree of roughness using negatively and positively charged polyelectrolytes and negatively charged silica nanoparticles (NPs). SEM (scanning electron microscopy) images represent the silica nanoparticles deposition on the surface of the thin film. The roughness of these thin films has been demonstrated by AFM (atomic force microscopy) investigation. The main characteristics of these surfaces are their high contact angle and low water contact angle hysteresis, which is achieved by the fluorinated lubricant that is infused in the pores of the films. The ice adhesion strength of the thin films was measured using a home-built normal mode tensile test in an environmental chamber, which confirmed the icephobicity of the surface as having an adhesion strength of less than 5 kPa, implying that this surface is an excellent candidate for passive removal of ice. The thin films were aged for up to 100 days, and the results showed that the thin film could reduce the ice adhesion strength by 65%, even after this period. The ice adhesion strength of the thin film after icing/deicing cycles showed that 80% of the icephobicity of the thin film had been preserved even after 50 cycles.

Ice accretion is the process by which a layer of ice builds up on solid objects that are exposed to freezing precipitation or supercooled cloud of droplets. In fact, the onset of ice accretion can be sudden and hazardous. This has motivated the development and deployment of icephobic coatings as an effective strategy to prevent or suppress ice accumulation on critical and functional surfaces. Previously, we reported a scalable technique to fabricate durable superhydrophobic coatings using siloxane-modified epoxy nanocomposites. Herein, we extend our earlier research by investigating the potential of using these nanocomposites as candidates for icephobicity. Accordingly, nanocomposites with varied silica nanoparticles’ concentrations were considered in our efforts to modify the surface energy and structure to transform the original superhydrophobic surface into an icephobic surface. Our results indicate that a highly superhydrophobic surface (25 wt% nanocomposite) can be ineffective in combating ice accretion at subfreezing temperatures. In contrast, a nanocomposite with a nanoparticles concentration of 35 wt% was found to (i) facilitate the full rebounding of supercooled droplets, while maintained at −10 °C, (ii) reduce the water nucleation temperature to −12 °C, (iii) delay the freezing process by ∼ 94 s at a temperature of −10 °C, and (iv) reduce the ice adhesion strength to ∼ 230 kPa. This comprehensive assessment of the different aspects of icephobicity was considered essential as it ensures the surface’s effectiveness against the variety of conditions that lead to ice accretion. Moreover, the developed nanocomposite coatings demonstrated excellent adhesion strength as well as consistent wettability and icephobicity after being subjected to numerous icing/thaw cycles. The outcome of our effort offers a great potential for the large-scale adoption of siloxane-modified nanocomposites in applications that require protection against ice accretion.

Hypothesis The accretion of ice on component surfaces often causes severe impacts or accidents in modern industries. Applying icephobic surface is considered as an effective solution to minimise the hazards. However, the durability of the current icephobic surface and coatings for long-term service remains a great challenge. Therefore, it is indeed to develop new durable material structures with great icephobic performance. Experiments A new design concept of combining robust porous metallic skeletons and icephobic filling was proposed. Nickel/polydimethylsiloxane (PDMS) two-phase layer was prepared using porous Ni foam skeletons impregnated with PDMS as filling material by a two-step method. Findings Good icephobicity and mechanical durability have been verified. Under external force, micro-cracks could easily initiate at the ice/solid interface due to the small surface cavities and the difference of local elastic modulus between the ice and PDMS, which would promote the ice fracture and thus lead to low ice adhesion strength. The surface morphology and icephobicity almost remain unchanged after water-sand erosion, showing greatly improved mechanical durability. By combining the advantages of the mechanical durability of porous Ni skeleton and the icephobicity of PDMS matrix, the Ni foam/PDMS two-phase layer demonstrates great potentials for ice protection with long-term service time.

Slippery liquid-infused porous surfaces (SLIPSs) have been actively studied to improve the limitations of superhydrophobic (SHP) surfaces, especially the defects of the nonwetting chemical coating layer and the weak mechanical robustness of surface micro/nanostructures. However, the SLIPSs also have several drawbacks including volatilization and leakage of lubricant caused by long-term usage. In this study, we suggest the use of icephobic, highly transparent, and self-healing solid slippery surface to overcome the limitations of both surfaces (SLIPS and SHP) by combining specific biomimetic morphology and intrinsic properties of paraffin wax. A moth-eye mimicking nanopillar structure was prepared instead of a porous structure and was coated with solid paraffin wax for water repellence. Moth-eye structures enable high surface transparency based on antireflective effect, and the paraffin layer can recover from damage due to sunlight exposure. Furthermore, the paraffin coating on the nanopillars provides an air trap, resulting in a low heat transfer rate, increasing freezing time and reducing adhesion strength between the ice droplet and the surface. The heat transfer model was also calculated to elucidate the effects of the nanopillar height and paraffin layer thickness. The antireflection and freezing time of the surfaces are enhanced with increase in nanopillar height. The paraffin layer slightly deteriorates the transmittance but enhances the icephobicity. The solar cell efficiency using a biomimetic solid slippery surface is higher than that of bare glass due to the antireflective effect. This integrated biomimetic solid slippery surface is multifunctional due to its self-cleaning, anti-icing, antireflection, and self-healing properties and may replace SLIPS and SHP surfaces.

Ice accumulation on wind turbine blades due to the impact of supercooled water droplets can be reduced by the application of surfaces with anti-icing properties. Hydrophobic surfaces are considered as a promising solution because of their water repellent behavior. In recent years, short-pulsed laser technologies have been developed as an efficient technique to modify the surface properties of materials. However, the anti-icing properties of such surfaces have not yet been validated. In this work, a hybrid modification of polyester resin-based gelcoats was adopted. Laser patterning (LP) was used to produce periodic surface structures on modified unsaturated polyester resin (UPR) substrates. One of the innovations of this research is the utilization of novel purpose-made chemical modifiers for gelcoats. The implementation of linear polymethylhydrosiloxane (PMHS) as a building block is a key improvement in terms of durability and functionality of the coating, since there is an option of introducing not only groups bonding in the polyester into one molecule, but also groups that increase hydrophobicity. The other novelty is a successfully conducted experiment combining such chemical modification with laser texturization of the surface. The influence of the laser energy, pattern shape, and spatial periods on the topographical characteristics and hydrophobicity as well as the anti-icing properties of the produced surfaces were investigated. To characterize the surface topography of the produced structures, scanning electron microscopy (SEM) and profilometer were utilized. Measurements of the wettability parameters (static contact angle and contact angle hysteresis) on the treated surfaces allowed the identification of the influence of wetting behavior and laser parameters on the investigated materials. Anti-icing properties were characterized by ice adhesion (IA) and freezing delay time (FDT) tests. It was found that hybrid modification of unsaturated polyester resin by chemical modifiers and laser treatment increased the hydrophobic and anti-icing properties of polyester gelcoats., This research was funded by National Centre for Research and Development (NCBiR), grant number LIDER/16/0068/L-9/17/NCBR/2018.

In this paper, hydrophobic nanocomposite coatings based on polyurethane (PUR) modified by nano-silica and silane-based compounds were manufactured by spraying. The main challenge was to assess and improve the hydrophobic as well as anti-icing properties of initially hydrophilic polymer coatings. The prepared nanocomposite coatings were characterized by means of scanning electron microscopy (SEM), optical profilometry and X-ray photoelectron spectroscopy (XPS). The results obtained showed that in order to achieve hydrophobicity, appropriate amounts of nano-silica must be incorporated in the coating, and complete coverage by nano-silica particles is necessary for achieving hydrophobicity. Coating adhesion and the durability of the hydrophobic behaviour were also studied by scratch test and frosting/defrosting cycles, respectively. The results show that use of both nano-silica and silane-based compounds improve the hydrophobic and anti-icing properties of the coating as compared to a non-modified PUR topcoat. A synergistic e ect of both additives was observed. It was also found that the anti-icing behaviour does not necessarily correlate with surface roughness and the materials’ wetting properties.

The roles of surface roughness on icephobicity including ice adhesion strength have been long debated in icephobicity studies. However, the direct/systematic influence of surface roughness on ice adhesion strength while keeping other surface characteristics such as surface wettability and interfacial cavitation unchanged are seldom reported. In this paper, systematic reduction of ice adhesion strength with the decrease in surface roughness regardless of the surface wettability was demonstrated across all the studied material types, i.e. metallic surfaces and polymeric coatings with different surface wettability. In-situ icing observation studies indicated that the ice did not anchor on smooth metallic surfaces and polymeric coatings but anchored on rough surfaces including superhydrophobic coatings. Effect of surface wettability was argued against the ice adhesion strength based on our results and similar ice adhesion strength was found on materials having different wettability (i.e. hydrophilic and hydrophobic coatings, and surfaces having different contact angle hysteresis). On the contrary, the introduction of low surface energy chemicals (via deposition and/or functionalization) on the surface having similar surface roughness showed a direct reduction of ice adhesion strength. These results indicated the surface roughness is vital in achieving icephobic performance, however, the ultra-low ice adhesion strength could be achieved by the synergetic effect of low surface roughness and low interfacial cavitation (in line with the interfacial correlation factor).

Surface icing affects the safety and performance of numerous processes in technology. Previous studies mostly investigated freezing of individual droplets. The interaction among multiple droplets during freezing is investigated less, especially on nanotextured icephobic surfaces, despite its practical importance as water droplets never appear in isolation, but in groups. Here we show that freezing of a supercooled droplet leads to spontaneous self-heating and induces strong vaporization. The resulting, rapidly propagating vapor front causes immediate cascading freezing of neighboring supercooled droplets upon reaching them. We put forth the explanation that, as the vapor approaches cold neighboring droplets, it can lead to local supersaturation and formation of airborne microscopic ice crystals, which act as freezing nucleation sites. The sequential triggering and propagation of this mechanism results in the rapid freezing of an entire droplet ensemble, resulting in ice coverage of the nanotextured surface. Although cascade freezing is observed in a low-pressure environment, it introduces an unexpected pathway of freezing propagation that can be crucial for the performance of rationally designed icephobic surfaces.

Icephobic/anti-icing materials have received growing attentions due to their great potential in reducing energy consumption. The aim of this presented work is to propose a superhydrophobic surface with microblock-nanohair hierarchical structures, and verify its water repellence and icephobic capacity. The hierarchical structures were fabricated by means of a combined method of electrochemical etching and hydrothermal treatment. Following this, the fluoridation modification was performed to obtain the superhydrophobicity with the water contact angle reaching 164° and the sliding angle of 1.5°. The dynamic droplet impacting on the hierarchical structure surface can rapidly rebounce off with the shorter contact time of 9.8 ms, displaying the robust dynamic water repellency. Comparing with the untreated substrate, the resultant superhydrophobic surface exhibited higher anti-icing property with the freezing time of a 4 μL reference droplet increasing from 11.3 s to ∼1700 s at −10 °C, and the ice adhesion force reducing to ∼35 kPa. Furthermore, the comparative studies with the other single-tier structure (i.e., microblock and nanohair structure) surfaces provided the necessary assistance to reveal the underlying action mechanism that the hierarchical micro-nanostructure induced more air pockets underneath droplets to produce the higher hydrophobicity and icephobic capacity.

Despite exceptional recent advances in tailoring the wettability of surfaces, to date, no engineered surface can passively suppress the in-plane growth of frost that invariably occurs in humid, subfreezing environments. Here, we show that up to 90% of a surface can exhibit passive antifrosting by using chemical or physical wettability patterns to template "ice stripes" across the surface. As ice exhibits a depressed vapor pressure relative to liquid water, these sacrificial ice stripes siphon the supersaturated water vapor to keep the intermediate surface areas dry from dew and frost. Further, we show that when these sacrificial ice stripes are elevated atop microfins, they diffusively coarsen in a suspended state above the surface. The suspended state of the coarsening ice results in a diffusive growth rate an order of magnitude slower than frost coarsening directly on a solid substrate and should also minimize its adhesive strength to the surface.

Icephobicity of materials has received intensive attention in recent years due to the increasing requirement of ice protection in aerospace, wind energy and power lines. However, the influencing factors of material icephobicity have not been well identified. In this work, the effect of surface gaseous adsorption on icing behaviour of materials was investigated for the first time. Ni-Cu-P coatings with different surface morphologies were fabricated and used as the objects of the study. Environmental scanning electron microscopy (ESEM) was utilized to observe the water condensation and ice formation on the coatings. X-ray photoelectron spectroscopy (XPS) was employed to analyse the variations of surface adsorption. Droplets icing time and ice adhesion strength of the coatings were also studied. The results showed that the icing time of water droplets on the Ni-Cu-P coatings increased significantly, and the ice adhesion strength decreased sharply with the spontaneous surface adsorption of gaseous species (mainly hydrocarbon groups) in air. The adsorbed hydrocarbon species would promote the formation of air pockets between the ice-coating interface, which could effectively reduce the interfacial contact of the formed ice with the coating. When the adsorbed hydrocarbon species were removed by plasma cleaning, water droplets tended to have more direct contacts with the coatings prior to icing, leading to the formation of interlocked ice and significantly increased the ice adhesion on the surface. The variation of surface icephobicity can also be attributed to the changes of surface energy due to the surface adsorption. The results indicated that the surface gaseous adsorption in air played an important role in determining the surface icing behaviour and the icephobicity of the materials.

Icephobic coating and surfaces are essential for protecting infrastructures such as transmission lines, transportation vehicles, and many others from severe damages of excessive icing. The slippery liquid-infused porous surfaces (SLIPS) are attracting escalating attention due to their low ice adhesion strength. Despite all the encouraging laboratory scale results, the SLIPS are still far from being applicable in real environments owing to the key unsolved problem, namely anti-icing durability. Inspired by the functionality of the amphibians’ skin, lubricant regenerability was introduced to conventional SLIPS and realized by a facile and scalable fabrication route. A series of polydimethylsiloxane (PDMS) based skin-like SLIPS were designed and fabricated by using one-step method, the solvent evaporation-induced phase separation technique. The obtained skin-like SLIPS were able to regenerate surface lubricant constantly by internal residual stress due to phase separation, and survived more than 15 cycles of wiping/regenerating tests. Thanks to the regenerability of the surface lubricant, the new SLIPS demonstrated durable icephobicity, showing a long-term low ice adhesion strength below 70 kPa, which was only 43% of 160 kPa that for the pristine PDMS (Sylgard 184), even after 15 icing/deicing cycles. This work paves a new and facile way for achieving icephobic durability of SLIPS. © 2018 American Chemical Society. This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes.

The present work investigates the effect of different process parameters on the production of low-density polyethylene (LDPE) coatings by flame spray technology. Previously, flame spraying of polymers has been successfully performed to obtain durable icephobic coatings, providing an interesting solution for applications facing icing problems, e.g. in marine, aviation, energy, and transportation industry. However, the fine tailoring of the process parameters represents a necessary strategy for optimising the coating production due to the unique thermal properties of each polymer. For this purpose, we vary the heat input of the process during flame spraying of the coating, by changing the transverse speed and the spraying distance. The results show that the variation in the process parameters strongly influenced the quality of the polymer coating, including its areal roughness, thickness, chemical composition, thermal stability, and degree of crystallinity. Furthermore, we demonstrate that these properties significantly affect the icephobic behaviour of the surface within the spray window of the chosen parameters. In conclusion, the relationship between the thermal degradation of the polymer and the icephobicity of the surface was defined. This highlights the importance of process parameter optimisation in order to achieve the desired icephobic performance of the LPDE coatings.

Coatings with anti-icing performance possess hydrophobicity and low ice adhesion strength, which delay ice formation and make ice removal easier. In this paper, the anti-icing performance of nano/microsilica particle-filled amino-terminated PDMS (A-PDMS)-modified epoxy coatings was investigated. In the process, the influence of the addition of A-PDMS on the hydrophobicity and ice adhesion strength was investigated. Furthermore, the influences of various weight ratios of nanosilica/microsilica (Rn/m) on the hydrophobicity and ice adhesion strength of the coating were investigated. Hydrophobicity was evaluated by contact angle (CA) and contact angle hysteresis (CAH) tests. Ice adhesion strength was measured by a centrifugal adhesion test. The addition of A-PDMS markedly increased hydrophobicity and decreased ice adhesion. The size combination of particles obviously affects hydrophobicity but has little effect on ice adhesion. Finally, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were used to reveal the anti-icing mechanism of the coatings.

Ice nucleation from vapor presents a variety of challenges across a wide range of industries and applications including refrigeration, transportation, and energy generation. However, a rational comprehensive approach to fabricating intrinsically icephobic surfaces for frost formation-both from water condensation (followed by freezing) and in particular from desublimation (direct growth of ice crystals from vapor)-remains elusive. Here, guided by nucleation physics, we investigate the effect of material composition and surface texturing (atomically smooth to nanorough) on the nucleation and growth mechanism of frost for a range of conditions within the sublimation domain (0 C to -55C; partial water vapor pressures 6 to 0.02 mbar). Surprisingly, we observe that on silicon at very cold temperatures-below the homogeneous ice solidification nucleation limit (< -46 C)-desublimation does not become the favorable pathway to frosting. Furthermore we show that surface nanoroughness makes frost formation on silicon more probable. We experimentally demonstrate at temperatures between -48 C and -55 C that nanotexture with radii of curvature within one order of magnitude of the critical radius of nucleation favors frost growth, facilitated by capillary condensation, consistent with Kelvin's Equation. Our findings show that such nanoscale surface morphology imposed by design to impart desired functionalities-such as superhydrophobicity-or from defects, can be highly detrimental for frost icephobicity at low temperatures and water vapor partial pressures (< 0.05 mbar). Our work contributes to the fundamental understanding of heterogeneous phase transitions well within the equilibrium sublimation domain and has implications for applications such as travel, power generation, and refrigeration.

Facile preparation of mechanically durable superhydrophobic materials is indispensable, however, there is an extensive list of requirements that are needed before the materials can have a broad range of applications in water environments. Limited durability, tedious chemical treatments, and complicated multi-step processing procedures have further constrained the practical applications of superhydrophobic materials. Herein, robust superhydrophobic stainless steel and copper meshes were fabricated through a one-step solution immersion method and endowed with remarkable multi-functions. The surface morphology, chemical composition and wettability of the as-fabricated superhydrophobic meshes were characterized. The as-prepared superhydrophobic meshes exhibited outstanding performances pertaining to water proofing, mechanical durability, self-cleaning and anti-fouling properties. More significantly, the superhydrophobic meshes possessed good oil–water separation, ice delay and icephobicity performances, and excellent anti-corrosion protective abilities. The experimental results indicated that the separation efficiencies of both the as-prepared superhydrophobic meshes for the oil–water mixtures were above 98%, and the water freezing times on the superhydrophobic meshes were delayed by more than twice those of the untreated meshes. In addition, the increase in the corrosion potential (Ecorr) and decrease in the corrosion current (Icorr) implied that the as-prepared superhydrophobic meshes have better corrosion resistance than the bare meshes. All of the attained functions above may promise potential application of these materials in practical water environments.

The development of techniques and methods to acquire icephobic surfaces is increasingly important, especially for polymers that are being employed in many fields of common life every day. In this work, we propose an alternative method for the preparation of easily applicable coating that can be used on a variety of polymers that enter in a wide range of applications. This approach is based on incorporating graphite spheres, vapor annealed with the polymer using the corresponding polymer's solvent, and subsequent grafting it with diazonium salt and grafting to the hydrophobic fluoro-containing chemical moieties. The morphology and surface chemistry of samples was characterized by different techniques. Mechanical tests on coating showed good adhesion on the polymer. The main advantage of this approach is that it is easy to apply, reliable, inexpensive, durable, and showed a significant change in wettability behavior and its icephobicity. The coating showed very low wettability with a water contact angle of 167°, with self-cleaning properties and a low sliding angle. The coating also results in significantly prolonging the time of the freezing of water drop, and considerably less ice adhesion on the surface compared to non-coated samples, which was shown by the results from different icephobicity tests.

Fluorinated polysiloxanes with different grafting densities of fluorinated groups were synthesized via hydrosilylation reaction between polymethylhydrosiloxane and tridecafluorooctyl methacrylate (13FMA). By further introduction of vinyltriethoxysilane (VTES), the produced polymers underwent self-crosslinking to generate icephobic coatings. Characterizations of surface chemical composition and morphology of the fluorinated polysiloxanes coatings suggested that the fluorine content and the surface roughness of the coating surface increased with the amount of 13FMA. When the fluorinated polysiloxanes grafted a suitable amount of 13FMA and VTES, supercooled water droplets could easily slip away from the tilted coating surface at − 15 °C, ascribing to its high receding contact angle, and the ice shear strength could reduce to 83 ± 2 kPa. Results of this study further demonstrated the importance of the synergistic effect of silicon and fluorine for contribution to the enhanced icephobicity, and the self-crosslinking fluorinated polysiloxane coatings could find more feasible applications for anti-icing.

Spontaneous removal of liquid, solidifying liquid and solid forms of matter from surfaces, is of significant importance in nature and technology, where it finds applications ranging from self-cleaning to icephobicity and to condensation systems. However, it is a great challenge to understand fundamentally the complex interaction of rapidly solidifying, typically supercooled, droplets with surfaces, and to harvest benefit from it for the design of intrinsically icephobic materials. Here we report and explain an ice removal mechanism that manifests itself simultaneously with freezing, driving gradual self-dislodging of droplets cooled via evaporation and sublimation (low environmental pressure) or convection (atmospheric pressure) from substrates. The key to successful self-dislodging is that the freezing at the droplet free surface and the droplet contact area with the substrate do not occur simultaneously: The frozen phase boundary moves inward from the droplet free surface toward the droplet-substrate interface, which remains liquid throughout most of the process and freezes last. We observe experimentally, and validate theoretically, that the inward motion of the phase boundary near the substrate drives a gradual reduction in droplet-substrate contact. Concurrently, the droplet lifts from the substrate due to its incompressibility, density differences, and the asymmetric freezing dynamics with inward solidification causing not fully frozen mass to be displaced toward the unsolidified droplet-substrate interface. Depending on surface topography and wetting conditions, we find that this can lead to full dislodging of the ice droplet from a variety of engineered substrates, rendering the latter ice-free.

Ice adhesion and accumulation are well known to cause serious problems for different structures such as wind turbines, power transmission and distribution systems, and aircraft. Development of coatings that can resist icing can solve many challenges in various areas of industry. This work was inspired by nature and ice resistivity and superhydrophobicity of plants leaves. Kale is a winter plant with superhydrophobic behaviors, which is normally known as an advantage for cleaning the leaves; however, this article reveals that kale leaves have special surface microstructures delaying the ice formation initiation making them good candidates for designing ice-repellent coatings. In-depth experimental analyses, IR thermography, contact angle measurements, and scanning electron microscopy of the leaves were performed to discover how different plants can prevent icing and further find an optimal design for an artificial ice-repellent coating.

Robust superhydrophobic coatings with anti-icing properties were obtained by a simple approach, i.e., immersing and spraying of adhesive/hydrophobic silica dispersion on fiberglass cloth. Scanning electron microscopy, water contact angles, abrasion tests and dynamic icing tests were performed to characterize the morphology, hydrophobicity, mechanical durability and icephobicity of the coatings. The experimental results demonstrated that the coatings have good abrasion resistance. The water contact angle and the water sliding angle remain greater than 150° and lower than 10°, respectively, after 60 cycles of abrasion. Furthermore, the anti-icing properties of superhydrophobic surfaces were investigated under dynamic flow conditions. It was found that the coatings had the ability to delay ice nucleation without electrical heating, and avoid ice adhesion partly or even completely, under a given mass of heat, which was much less than that of uncoated surfaces. The fiberglass cloth based coatings could reduce by up to 51% of the heating power required to avoid ice accumulation, compared to uncoated surfaces.

The poor mechanical strength of superhydrophobic surface limits its use in civil aviation. In this work, superhydrophobic surfaces with open and closed microstructure design were prepared, and their hydrophobicity and icephobicity over icing/de-icing cycles were thoroughly studied. For all samples, contact angle decreased and contact angle hysteresis increased over time. However, surface with interconnected hollow honeycomb microstructure design kept its Cassie–Baxter state even after 20 times icing/de-icing cycles, while surface with repeated individual post microscopic unit lost its superhydrophobicity only after six times icing/de-icing cycles. The interconnected hollow honeycomb microstructure design strengthened surface mechanical strength by lowering the damage to microscopic unit. The freezing time for water droplet on surface with interconnected hollow honeycomb microstructure design was only slightly shortened over time. The difference in water/ice-solid contact area for surfaces with different nano-microscale design also led to the difference in wetting and ice-retarding ability. Surface with interconnected hollow honeycomb microstructure design showed the strongest ice-retarding ability followed by surface with interconnected hollow brick, ladder type, and triangle shape microstructure design. © 2017 Curtin University of Technology and John Wiley & Sons, Ltd.

Recent emerging strategies to prepare icephobic coatings have focused on slippery surfaces containing a liquid lubricant with low surface energy, which significantly reduces ice adhesion. In this work, a facile technique was developed for preparation of polysiloxane coatings with efficient and durable icephobicity. Fluorinated polyhedral oligomeric silsesquioxanes (F-POSS-SiH) with different fluorinated groups and Si-H active sites were synthesized via hydrosilylation between fluorinated methacrylates and octakis(dimethylsiloxy) octasilsequioxane. The F-POSS-SiH hybrid compound was subsequently applied as a co-crosslinker in the system of polymethylhydrosiloxane (PMHS) and polymethylvinylsiloxane to create silicone coatings. The low surface energy of fluorinated groups could drive F-POSS-SiH towards the coating surface, leading to a gradient distribution in which F-POSS-SiH was self-assembled on the top surface, while silicone was rich in the bottom layer. Meanwhile, wavy surfaces were generated spontaneously by compressive stress during the coating formation. The wavy microstructure of coatings provided space for the unreacted silicone oil, i.e., low molecular weight PMHS, that could be considered as a liquid lubricant and controlled by the dosage. Therefore, the slippery wavy coatings showed highly icephobic properties with extraordinarily low ice shear strengths at a lowest value of 3.8 ± 1.8 kPa, only 5 percentage of Sylgard 184. Moreover, the coatings remained icephobicity after 15 icing/deicing cycles, demonstrating excellent durability.

Preventing icing on exposed surfaces is important for life and technology. While suppressing ice nucleation by surface structuring and local confinement is highly desirable and yet to be achieved, a realistic roadmap of icephobicity is to live with ice, but with lowest possible ice adhesion. According to fracture mechanics, the key to lower ice adhesion is to maximize crack driving forces at the ice-substrate interface. Herein, we present a novel integrated macro-crack initiator mechanism combining nano-crack and micro-crack initiators, and demonstrate a new approach to designing super-low ice adhesion surfaces by introducing sub-structures into smooth polydimethylsiloxane coatings. Our design promotes the initiation of macro-cracks and enables the reduction of ice adhesion by at least ∼50% regardless of the curing temperature, weight ratio and size of internal holes, reaching a lowest ice adhesion of 5.7 kPa. The multiscale crack initiator mechanisms provide an unprecedented and versatile strategy towards designing super-low ice adhesion surfaces.

Although the superhydrophobic surfaces are preferable for passive anti-icing systems, as they provide water shedding before initiation of ice nucleation, their practical usage is still under debate. This is so, as the superhydrophobic materials are not necessarily icephobic and most of the synthesis techniques are characterized with low fabrication scalability. Here, we describe a rational strategy for the atmospheric icing prevention, based on chemically functionalized carbon soot, suitable for large-scale fabrication of superhydrophobic coatings that exhibit and retain icephobicity in harsh operational conditions. This is achieved through a secondary treatment with ethanol and aqueous fluorocarbon solution, which improves the coating’s mechanical strength without altering its water repellency. Subsequent experimental analyses on the impact dynamics of icy water droplets on soot coated aluminum and steel sheets show that these surfaces remain icephobic in condensate environments and substrate temperatures down to −35 °C. Furthermore, the soot’s icephobicity and non-wettability are retained in multiple icing/de-icing cycles and upon compressed air scavenging, spinning and water jetting with impact velocity of ∼25 m/s. Finally, on frosted soot surfaces, the droplets freeze in a spherical shape and are entirely detached by adding small amount of thermal energy, indicating lower ice adhesion compared to the uncoated metal substrates.

The accretion of ice and frost on various infrastructure is ubiquitous in cold and humid environments, causing economic losses amounting to billions of dollars every year worldwide. The past couple of decades have seen unprecedented advances in the fields of surface chemistry and micro/nanofabrication, enabling the development of hydrophobic and superhydrophobic surfaces that promote facile deicing and/or passive anti-icing. However, in the light of new discoveries regarding the incipient stages of frost formation, it is becoming increasingly clear that the problems of icing and frosting are not one and the same. Thus, passive anti-icing strategies do not exhibit anti-frosting behavior, and the development of passive anti-frosting surfaces remains an unsolved problem. In this review, we provide a critical discussion of condensation frosting and show how the emerging new phenomena of frost halos, interdroplet ice bridges, and dry zones that comprise the incipient stages of frosting set it apart fro...

Four polydimethylsiloxane (PDMS) coatings with different surface free energies have been prepared and applied to smooth and roughened aluminum plates to form hydrophobic and superhydrophobic surfaces. Their surface wettability in terms of water contact angle (CA), sliding angle (SA) and water droplet impact dynamics was studied under an ambient (50% relative humidity, RH at 25 °C) and three different condensing environments (low, highly and extremely condensing, i.e. 30%, 60% and 90% RH at −10 °C). In addition, the surface ice adhesion was investigated under the extremely condensing condition. Different PDMS coatings on either smooth or roughened surfaces displayed a very similar impact to static and dynamic wettability under the ambient environment. However, the water impact behavior and ice adhesion under the extremely condensing condition between the hydrophobic and superhydrophobic surfaces are significantly different. One of the superhydrophobic surfaces (R2180) demonstrated an excellent water repelling capability to retard ice accumulation, and reduced ice adhesion strength even under the extremely condensing condition, and thus will be a good candidate for ice-phobic applications. This excellent ice-phobic property is attributed to the low surface free energy of the coating, which effectively prevents the water condensation inside the cavities of the hierarchical superhydrophobic structures and thus maintains “air cushion” on the solid/water interface, indicated by a very low solid-liquid contact area increase after surface is exposed to this condensing weather condition. This result demonstrates that the “air cushion” in a superhydrophobic surface could be maintained even under an extremely condensing condition by carefully selection of coating composition with a very low surface free energy.

State-of-the-art passive icephobicity relies mainly on static parameters such as surface energy, coating elastic modulus, crack sizes and so on. Low ice adhesion resulting from the dynamic de-icing process, for instance ice detaching modes from substrates, has not yet been explored. In the current study, atomistic modeling and molecular dynamics simulations were employed to identify ice rupture modes as crucial dynamic factors for surface icephobicity. A fish-scale-like icephobic surface prototype enabling low-adhesion sequential rupture of the atomistic interactions at the ice-solid interface was proposed. The novel surface has an intrinsic extended interface rupture pathway, which can lead to a ∼60% reduction in atomistic ice adhesion compared with concurrent ice rupture. This study sheds light on interface mechanical design for surface icephobicity, and could provide solutions for anti-icing, nanoscale tribology and many others. The concept of implementing interfacial rupture modes proposed in this study can also apply to interface design for tailored adhesion mechanics.

Until recently, superhydrophobicity was considered as a hint to predict surface icephobicity, an association of concepts that is by no means universal and that has been proven to depend on different experimental factors and material properties, including the actual morphology and chemical state of surfaces. This work presents a systematic study of the wetting and freezing properties of aluminum Al6061, a common material widely used in aviation, after being subjected to nanosecond pulsed IR laser treatments to modify its surface roughness and morphology. All treated samples, independent of their surface finishing state, presented initially an unstable hydrophilic wetting behavior that naturally evolved with time to reach hydrophobicity or even superhydrophobicity. To stabilize the surface state and to bestow the samples with a permanent and stable hydrophobic character, laser-treated surfaces were covered with a thin layer of CFx prepared by plasma-enhanced chemical vapor deposition. A systematic comparison between freezing delay (FD) and wetting properties of water droplets onto these plasma-/polymer-modified laser-treated surfaces that, under conditions where a heterogeneous nucleation mechanism prevails, surface morphology rather than the actual value of the surface roughness parameter the key feature for long FD times. In particular, it is found that surface morphologies rendering a Cassie–Baxter wetting regime longer FDs than those characterized by a Wenzel-like wetting state. It is that laser treatment, with or without additional coverage with thin CFx coatings, affects wetting and ice formation behaviors and might be an efficient procedure to mitigate icing problems on metal surfaces., This work has been carried out with the support of the EU project PHOBIC2ICE (ref 690819). The authors also thank the European Regional Development Funds program (EU-FEDER) and the MINECO-AEI (201560E055 and MAT2016-79866-R and network MAT2015-69035-REDC) for financial support.

Anti-icing/icephobic coatings, typically applied in the form of surface functional materials, are considered to be an ideal selection to solve the icing issues faced by daily life and industrial production. However, the applications of anti-icing coatings are greatly limited by the two main challenges: bonding strength with substrates and stability of the high anti-icing performance. Here, we designed and fabricated a kind of high-performance superhydrophobic fluorinated silica (F-SiO2)@polydimethylsiloxane coatings and further emphasized the improvement of the bonding strength with substrates and the maintenance of high anti-icing performance. The resultant coatings exhibited excellent water repellency with a contact angle up to 155.3° and a very short contact time (∼10.2 ms) of impact droplets. At low temperatures, the coming droplets still rapidly rebounded off the coating surface, and the superhydrophobic coatings displayed a more than 50-fold increase of freezing time comparing with bare aluminum. The ice adhesion strength on the coatings was only 26.3 kPa, which was far less than that (821.9 kPa) of bare aluminum. Furthermore, the nanoporous structures constructed by anodic oxidation could tremendously enhance the bonding strength of the coatings with the substrate, which was evaluated through a standard method (ASTM D3359). The anti-icing properties still retained high stability under the conditions of 30 icing/deicing cycles, soaking, and scouring of acid solution (pH = 5.6). This work can effectively push the anti-icing coatings toward a real-world application.

Macro-textured superhydrophobic surfaces can reduce droplet-substrate contact times of impacting water droplets, however, surface designs with similar performance for significantly more viscous liquids are missing, despite their importance in nature and technology such as for chemical shielding, food staining repellency, and supercooled (viscous) water droplet removal in anti-icing applications. Here, we introduce a deterministic, controllable and up-scalable method to fabricate superhydrophobic surfaces with a 3D-printed architecture, combining arrays of alternating surface protrusions and indentations. We show a more than threefold contact time reduction of impacting viscous droplets up to a fluid viscosity of 3.7mPa s, which equals 3.7 times the viscosity of water at room temperature, covering the viscosity of many chemicals and supercooled water. Based on the combined consideration of the fluid flow within and the simultaneous droplet dynamics above the texture, we recommend future pathways to rationally architecture such surfaces, all realizable with the methodology presented here., ACS Appl. Mater. Interfaces, Article ASAP, Publication Date (Web): November 19, 2018

Inhibiting ice accumulation on surfaces is an energy-intensive task and is of significant importance in nature and technology where it has found applications in windshields, automobiles, aviation, renewable energy generation, and infrastructure. Existing methods rely on on-site electrical heat generation, chemicals, or mechanical removal, with drawbacks ranging from financial costs to disruptive technical interventions and environmental incompatibility. Here we focus on applications where surface transparency is desirable and propose metasurfaces with embedded plasmonically enhanced light absorption heating, using ultra-thin hybrid metal-dielectric coatings, as a passive, viable approach for de-icing and anti-icing, in which the sole heat source is renewable solar energy. The balancing of transparency and absorption is achieved with rationally nano-engineered coatings consisting of gold nanoparticle inclusions in a dielectric (titanium dioxide), concentrating broadband absorbed solar energy into a small volume. This causes a > 10 {\deg}C temperature increase with respect to ambient at the air-solid interface, where ice is most likely to form, delaying freezing, reducing ice adhesion, when it occurs, to negligible levels (de-icing) and inhibiting frost formation (anti-icing). Our results illustrate an effective unexplored pathway towards environmentally compatible, solar-energy-driven icephobicity, enabled by respectively tailored plasmonic metasurfaces, with the ability to design the balance of transparency and light absorption.

Icephobic surfaces have a critical footprint on human daily lives ranging from aviation systems and infrastructures to energy systems, but creation of these surfaces for low-temperature applications remains elusive. Non-wetting, liquid-infused and hydrated surfaces have inspired routes for development of icephobic surfaces. However, high freezing temperature, high ice adhesion strength and subsequent ice accretion, low mechanical durability, and high production cost have restricted their practical applications. In this review, we provide a comprehensive definition for icephobicity through thermodynamics, heat transfer and mechanics of ice/water-material interface and elucidate physic-based routes through which nano-scale could help to achieve exceptional icephobic surfaces. Based on conservation laws, mathematical models are developed that accurately predict ice growth rate on various substrates and wind conditions. Through physics of fracture at ice-icephobic material interface, we cast a standard method for ice adhesion measurement that has the potential to eliminate discrepancies between reported ice adhesion from different laboratories. To assure long-time performance of icephobic surfaces, durability metrics need to be defined. We provide standard methods to examine mechanical, chemical, and environmental durability of icephobic surfaces. In the developed comprehensive framework on icephobicity in this review, performance of state-of-the-art icephobic surfaces are compared and main deficiencies in this field are highlighted.

A finite difference time domain (FDTD) simulation was adopted to initially illuminate a neglected phenomenon that SiO2 nanospheres in superhydrophobic layer could enhance the light absorption capacity of the layer itself, and of the contiguous photothermal semiconductor simultaneously. Guided by this simulation, a solar thermal coating (STC) composed of superhydrophobic SiO2 nanospheres and CuFeMnO4/PDMS was assembled to achieve highly efficient icephobicity. The accurate tests illustrated the temperature rise originated from the semiconductor layer by photothermal effect and superhydrophobic layer by self-heating effect, which was consistent with the simulation results. Depending on the high photothermal conversion efficiency, the freezing temperature of droplets on STC dropped to −35 °C, the ice adhesion strength decreased from 78.5 kPa to 12.1 kPa and an ice layer was removed within 99 s under the light illumination. Furthermore, STC could be further adopted in a cold natural environment, and deicing in 12 min. The simulation-guided construction of STC provides a new design strategy for icephobic coatings and new insights on energy management analysis in superhydrophobic photothermal composite coating.

Polysiloxane is one of the most favorite polymeric materials used in the emerging field of passive surface icephobicity; This is due to its tailorable softness, hydrophobicity, and relatively high durability. Given the state-of-the-art ice adhesion strength of polysiloxane surfaces has reached a threshold below 1 kPa, a timely survey on the published polysiloxane icephobic surfaces can serve as a valuable reference concerning how far the research field has already progressed and how much potential remains to be exploited for the future development of polymeric icephobic materials. This review categorizes the use of polysiloxane materials for icephobic strategies into three classes according to their surface stiffness. The advantages and shortcomings of each polysiloxane material group are assessed. By scrutinizing the current ice adhesion strength theory, a reference coating thickness is identified, which can be used for optimizing icephobic coating design. A surface icephobicity diagram is also presented, where a lower bound of ice adhesion on a smooth surface is derived, depicting the needs of incorporating different mechanisms to break the theoretical low ice adhesion limit. Finally, the challenges in applying the polysiloxane icephobic materials are discussed, and the possible key research directions are highlighted. 2020 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Ice accumulation on outdoor structures can cause costly damage to this exposed infrastructure. Research has therefore focused on means of protecting these surfaces from ice coverage. A promising approach is the design of anti-icing surfaces and, in particular, the development of slippery liquid-infused porous surfaces (SLIPS) for icephobic applications. SLIPS involve a lubricant being infused into the porous structures of the surface, thereby eliminating water condensation in pores and reducing ice adhesion. Liquid-infused surfaces also exhibit an extreme liquid repellency, showing a low contact angle hysteresis of

We prepared superhydrophobic surfaces (SHS) with various morphologies on 7075 aluminum, demonstrating that the SHS with small nanoscale asperities of ~80 nm yielded the lowest ice adhesion forces of ~80 kPa, due to the lubricating effect of the overcooled water, and the ice menisci caused by the high surface roughness deteriorated the surface’s icephobicity. To overcome this, slippery lubricant-infused porous surfaces (SLIPS) were prepared, only to find that the removal ability of water on SLIPS was not sufficient to represent its anti-icing ability, and the ice-adhesion force on SLIPS exhibited a negative correlation with the surface roughness.

This work concentrated on the fabrication of effective slippery liquid-infused porous surfaces (SLIPSs) to robustly resist ice adhesion by using facile method and smart composition. Firstly, poly(methyl methacrylate) (PMMA), polyhedral oligomeric silsesquioxane end-functionalized PMMA (POSS-ef-PMMA) and polydimethylsiloxane-blocked PMMA (PDMS-b-PMMA) were synthesized. Secondly, micro-sized pores arranged in a three-layer honeycomb-like array at a thickness of ca. 10 μm were elicited on each surface of these three cast polymer films by breath-figure (BF) method. After a separate infiltration of polydimethylsiloxane (PDMS), poly (hydrogenmethylsiloxane) (PHMS) and hexadecane (HD) into the porous matrixes, typical SLIPSs were formed. PDMS-b-PMMA matrix with preferential lipophilicity towards PDMS endowed the obtained SLIPS with better icephobicity. However, HD-induced SLIPSs performed the lowest sliding angles at 6° for 3 μL of water droplet, the lowest ice adhesional strength ranging from 40.8–46.3 kPa and the most robust anti-icing properties of resisting more than 30 icing/de-icing cycles without changing the ice adhesional strength. Such effective anti-icing performance was ascribed to the better liquid nature of HD in contact with water and the solid nature of HD under freezing condition, which could decrease the interfacial friction and abrasion of HD against water or ice.