Ice Adhesion Force Research Articles

Development of polyurethane urea（PUU）– Waste rubber particles (WRP) composite materials for active ice-breaking of groove-filled asphalt pavement

The grooved-filled asphalt pavement has certain advantages in terms of pavement ice-breaking and anti-skid. However, the performances of the filling material limit its development. In this study, a polyurethane urea (PUU) - waste rubber particles (WRP) composite filling material was prepared by using a polyurethane (PU) and adding polyurea (PUa) with a similar microstructure as the cementing material, and adding WRP as the elastic reinforcing phase. The proportions of nine PUU-WRP composite materials were designed by changing the particle size and content of WRP, and then the filled composite materials were evaluated in terms of physical and mechanical properties, ice adhesion properties, interface bonding properties and aging resistance. The test results showed that the shore hardness, tensile strength, compression permanent deformation, and contact angle of PUU-WRP composite decreased as content of the WRP increased. Except the ice adhesion force results were the opposite. On the other hand, increased the WRP size resulted in increase in PUU-WRP composite’s shore hardness, compression permanent deformation, and ice adhesion force, while the tensile strength and contact angle were the opposite. The surface of the PUU-WRP composite material was hydrophobic, and the maximum contact angle was 102.3°. The reduction of WRP particle size and dosage was beneficial for reducing the ice adhesion force on the surface of PUU-WRP composite materials. The maximum interfacial shear and tensile strength of PUU-WRP composite material were 1.082 MPa and 0.244 MPa, respectively. After 42 days of UV aging, the maximum attenuation rate did not exceed 30 %. After the immersion test, the tensile strength attenuation of PUU-WRP composite material was basically controlled within 10 %. Finally, based on the fuzzy comprehensive evaluation (FCE) method, it was recommended to use WRP with a particle size of 0.6 mm and a dosage of 30 wt%-40 wt%.

Robust and Superhydrophobic Polydimethylsiloxane/Ni@Ti3C2Tx Nanocomposite Coatings with Assembled Eyelash-Like Microstructure Array: A New Approach for Effective Passive Anti-Icing and Active Photothermal Deicing.

To solve the problem of ice condensation and adhesion, it is urgent to develop new anti-icing and deicing technologies. This study presented the development of a highly efficient photothermal-enhanced superhydrophobic PDMS/Ni@Ti3C2Tx composite film (m-NMPA) fabricated cost-effectively and straightforwardly. This film was fabricated utilizing PDMS as a hydrophobic agent, adhesive, and surface protector, while Ni@Ti3C2Tx as a magnetic photothermal filler innovatively. Through a simple spraying method, the filler is guided by a strong magnetic field to self-assemble into an eyelash-like microstructure array. The unique structure not only imparts superhydrophobic properties to the surface but also constructs an efficient "light-capturing" architecture. Remarkably, the m-NMPA film demonstrates outstanding superhydrophobic passive anti-icing and efficient photothermal active deicing performance without the use of fluorinated chemicals. The micro-/nanostructure of the film forms a gas layer, significantly delaying the freezing time of water. Particularly under extreme cold conditions (-30 °C), the freezing time is extended by a factor of 7.3 compared to the bare substrate. Furthermore, under sunlight exposure, surface droplets do not freeze. The excellent photothermal performance is attributed to the firm anchoring of nickel particles on the MXene surface, facilitating effective "point-to-face" photothermal synergy. The eyelash-like microarray structure enhances light-capturing capability, resulting in a high light absorption rate of 98%. Furthermore, the microstructure aids in maintaining heat at the uppermost layer of the surface, maximizing the utilization of thermal energy for ice melting and frost thawing. Under solar irradiation, the m-NMPA film can rapidly melt approximately a 4 mm thick ice layer within 558 s and expel the melted water promptly, reducing the risk of secondary icing. Additionally, the ice adhesion force on the surface of the m-NMPA film is remarkably low, with an adhesion strength of approximately 4.7 kPa for a 1 × 1 cm2 ice column. After undergoing rigorous durability tests, including xenon lamp weathering test, pressure resistance test, repeated adhesive tape testing, xenon lamp irradiation, water drop impact testing, and repeated brushing with hydrochloric acid and particles, the film's surface structure and superhydrophobic performance have remained exceptional. The photothermal superhydrophobic passive anti-icing and active deicing technology in this work rely on sustainable solar energy for efficient heat generation. It presents broad prospects for practical applications with advantages such as simple processing method, environmental friendliness, outstanding anti-icing effects, and exceptional durability.

Study of the active anti-icing properties of modified biological antifreeze protein micro-surfacing

The accumulation of snow and ice on the surface of roadways can threaten driving safety, which is a major pain point in winter. To address the issue of pavement icing, this paper researched the biological antifreeze protein (AFP) filler, which was then mixed with a portion of mineral powder to create a blend. This blend was further combined with emulsified asphalt modified by a combination of styrene-butadiene rubber (SBR) and waterborne epoxy resin (WER) to produce a micro-surfacing mixture with active anti-icing capabilities. The road performance tests were conducted to assess whether the anti-icing micro-surfacing mixture’s road performance was affected. Subsequently, improved and innovative anti-icing tests were conducted to evaluate the anti-icing performance of the anti-icing micro-surfacing. The anti-icing tests encompassed freezing tests, ice-melting and snow-melting tests, active de-icing simulation tests, and ice adhesion force tests. The road performance tests indicate that the incorporation of antifreeze filler enhances the resistance of the micro-surfacing mixture against water erosion during freeze-thaw cycles, with a minimal impact on rutting resistance and abrasion resistance. The freezing test demonstrates the excellent active antifreeze function of the anti-icing micro-surfacing. Furthermore, the ice-melting and snow-melting test reveals that the anti-icing micro-surfacing effectively speeds up the melting process of snow and ice on the surface of roadways. The active de-icing simulation test and adhesion test confirm that the anti-icing micro-surfacing significantly accelerates the rate of active de-icing. Overall, the anti-icing micro-surfacing demonstrates a significant active anti-icing effect while maintaining its road performance capabilities.

Comparative Evaluation of the Shear Adhesion Strength of Ice on PTFE Solid Lubricant

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.

Facile Preparation of Robust Superamphiphobic Coatings on Complex Substrates via Nonsolvent-Induced Phase Separation.

Superamphiphobic surfaces have great potential in many fields but often suffer from complicated, expensive, and time-consuming preparation methods, difficulty in applying them on complex substrates, and low stability. Herein, we show a facile fabrication of robust superamphiphobic coatings on complex substrates. A stock suspension was prepared by nonsolvent-induced phase separation of a silicone-modified polyurethane (Si-PU) adhesive containing fluorinated silica (FD-silica) nanoparticles. Then, superamphiphobic surfaces could be easily fabricated via dip coating in the suspension. The influences of phase separation and Si-PU/FD-silica ratio on the wettability and morphology of the coatings were studied. The coatings feature a microscale dense and nanoscale rough texture due to phase separation and rapid solvent evaporation, which enhances the stability by forming strong linkages among the nanoparticles while achieving high superamphiphobicity by trapping air stably in the nanopores. Consequently, the coatings show excellent static/dynamic superamphiphobicity, superior impalement resistance, and good mechanical, chemical, thermal, and UV aging stability. Additionally, the coatings have good anti-icing performance as demonstrated by the greatly extended water freezing time and weakened ice adhesion force in both simulated and real conditions.

TiO2-based slippery liquid-infused porous surfaces with excellent ice-phobic performance

Ice formation and accretion on surfaces of instruments such as infrastructures, power lines and aircrafts can trigger serious social danger, economic loss and threaten the safety of lives. It is of practical significance to develop functionalized passive anti-icing surfaces. Herein, we synthesized titanium dioxide nanotube arrays on titanium substrate through anodic oxidation method. The TiO2 nanotube arrays were further modified and infused with perfluoropolyether (PFPE) lubricant to form slippery liquid-infused porous surfaces (SLIPS). The relationship of the nanostructures and the slippery performance, the liquid holding property and anti-icing property of TiO2 based SLIPS was investigated in details. The contact angle hysteresis (CAH) and sliding angles of water droplets on the TiO2 SLIPS are as low as 1° and 4°, respectively, indicating the excellent slippery property of the SLIPS. The CAH of water droplets on TiO2 SLIPS could be still as low as 5° after being treated with 100 mL of flowing water, which show the long term stability and superior liquid holding property of the TiO2 SLIPS. We propose that the excellent slippery property and long term stability for holding liquid of TiO2 SLIPS attribute to the uniform nanostructures, the small diameter of the nanotubes, the smooth surface and high capillary force of TiO2 nanotube arrays. Both the icing delay tests and the ice adhesion force tests conducted on TiO2 SLIPS indicate that the long-term ice-phobic stability is strongly correlated with the surface smoothness and uniformity of nanostructures. The results show that large water droplets with size about 15 μL on TiO2 NT based SLIPS can keep as liquid phase at very low temperature (–15 ℃) for up to 24 h, which exhibits much longer icing delay time at –15 ℃ than most of the reported superhydrophobic surfaces and SLIPS. And the TiO2 SLIPS exhibit very good icing delay effect even after being reused for 17 times at –15 ℃, indicating the superior long-term stability and anti-icing effect of TiO2 SLIPS as passive ice-phobic surfaces. The ice adhesion force of icicles on TiO2 SLIPS was as low as ∼50 kPa after the tenth test, further indicating their long-term stability as anti-icing surfaces. In summary, the TiO2 nanotube arrays based SLIPS obtained in this work exhibit superior slippery property, anti-biofouling, excellent anti-icing property and long term stability after being treated with a large amount of flowing water or reused for many times under very low temperature. This work shows that SLIPS can be applied as ice-phobic surfaces with long term stability at low temperature, potentially useful for their practical applications as anti-icing and ice-phobic surfaces.

All-organic superhydrophobic coating with anti-corrosion, anti-icing capabilities and prospective marine atmospheric salt-deliquesce self-coalesce protective mechanism

Water-repellent and interfacial non-wetting superhydrophobicity has great potential to address corrosion/icing-induced material-deterioration problems. Herein, an all-organic superhydrophobic coating was constructed using facile and substrate-independent spray-coating method based on PTFE and PDMS. FE-SEM, EDS, and XPS techniques were used to analyze the surface topographies and chemical compositions. The coating exhibits superior anti-fouling and self-cleaning properties against various liquid and solid contaminants due to the synergic effect of low surface energy and hierarchical structures. The EIS and potentiodynamic polarization results show improved charge transfer resistance (Rct), positive shifted corrosion potential (Ecorr), and decreased corrosion current density (Icorr), implying significantly enhanced anti-corrosion performance with 99.83 % inhibition efficiency. Besides, the delay rate of ice-freezing time of the coating is 232 % at −5°C, 137 % at −10 °C and 204 % at −15 °C compared with uncoated Q235 substrate respectively. The ice adhesion strength of the coating accounts for only 6.55 % at −5°C, 7.03 % at −10 °C and 9.35 % at −15 °C than that of the bare Q235 carbon steel, demonstrating ultra-low ice adhesion force and anti-icing capabilities. The hygroscopic and deliquesce behaviors of NaCl salt particles reveal an intriguing salt-deliquescence self-coalescence phenomenon and prospective anti-corrosion mechanism for superhydrophobic materials in high-humidity marine atmospheric environments.

Durable superhydrophobic EVA cellular material spin-coated by SiO2/SEBS-g-MAH toward self-cleaning roofs

Ethylene-vinyl acetate copolymer (EVA) cellular material as one of important porous materials has been employed in the fields of outdoors cushioning. However, studies toward the construction of superhydrophobic structures on its surface for outdoor hygiene remains inadequate. In this work, a series of durable superhydrophobic SiO2/maleic anhydride grafted styrene-ethylene-butylene-styrene (SEBS-g-MAH) coatings with different weight contents of SiO2 were spin-coated on EVA cellular material's surface. 5Si-5S (50 wt% SiO2 and 50 wt% SEBS-g-MAH) coating showed water contact angle (WCA) of 162° and sliding angle of 6.3°. Meanwhile, 5Si-5S surface exhibited significant self-cleaning, anti-fouling and long-term water impact resistance abilities. Compared with Control sample, a freezing delay time of ~120 s and the 0.86 N reduction of ice adhesion force can also be realized. Contact angle values of 5Si-5S surface fluctuated around 160° as the pH of droplet changed in the range of pH 2–13. Moreover, the adhesive rate can reach 4B according to the ASTM D3359 and WCA can remain 150° after sandpaper abrasion, indicating its durability of hydrophobicity. The as-prepared EVA cellular material with durable superhydrophobic coating was expected as an outdoor building roof material toward self-cleaning and anti-icing application.

Novel Intrinsic Self-Healing Poly-Silicone-Urea with Super-Low Ice Adhesion Strength.

Accumulation of snow and ice often causes problems and even dangerous situations for both industry and the general population. Passive de-icing technologies, e.g., hydrophobic, liquid-infused bionic surfaces, have attracted more and more attention compared with active de-icing technologies, e.g., electric heating, hot air heating, due to the passive de-icing technology's lower energy consumption and sustainability footprint. Using passive de-icing coatings seems to be one of the most promising solutions. However, the previously reported de-icing coatings suffer from high ice adhesion strength or short service life caused by wear. An intrinsic self-healing material based on poly-silicone-urea is developed in this work to address these problems. The material is prepared by introducing dynamic disulfide bonds into the hard phase of the polymer. Experimental results indicate that this poly-silicone-urea has a self-healing efficiency of close to 99%. More interestingly, it is found that the coating prepared from this poly-silicone-urea has a super low ice adhesion force, only 7 ± 1 kPa, which is almost the lowest value compared with previous intrinsic self-healing de-/anti-icing reports. This material can maintain low ice adhesion strength after healing. This intrinsic self-healing poly-silicone-urea can meet several practical applications, opening the door for future sustainable anti-/de-icing technologies.

Anti‐icing polyimide thin film with microcolumns fabricated by RIE with cooling and PCVD

Anti-icing polyimide (PI) thin films are a promising anti-icing technology for aircraft. A processing method combining reactive ion etching with cooling and plasma chemical vapour deposition is proposed to fabricate anti-icing PI thin films with microcolumns (PI-M). The anti-icing performance of PI-M was examined. The apparent contact angle (APCA) was 153° ± 1.4°, and the APCA hysteresis was 8.5° ± 0.5°. The calculated Weber number was high, and a droplet on PI-M rebounded within 2.56 s, whereas rebounding occurred more slowly on a smooth PI surface (PI-S). The freezing time of droplets on PI-M was 70% longer than that on PI-S. The average ice adhesion force on PI-M was 42% smaller than that on PI-S. Repeated measurements of the ice adhesion force on PI-M demonstrated that it was stable (deviation: ±1 N). The APCA showed that PI-M is superhydrophobic, which indicates that droplets on PI-M were in the Cassie state. The droplet bouncing behaviour was explained in terms of horizontal force equilibrium at the interface. The anti-icing mechanism of PI-M was modelled using heterogeneous nucleation theory and a contact area model. The results explained the good anti-icing performance and suggested that PI-M may have excellent potential for anti-icing applications.

Preparation and anti-icing performance of cross-linked polysiloxane coatings containing silicone oil

In this work, a cross-linked polysiloxane coating containing silicone oil was prepared via a simple two-component mixing method and the anti-icing performance of the coating was investigated by detecting the ice adhesion force (τice) on the coating. The results of infrared spectroscopy and solvent swelling show that the polysiloxane coating with a certain cross-link density can be prepared by the reaction of methylhydrosiloxane and dimethylsiloxane copolymer and divinyl-terminated polysiloxane, and the cross-link density of the coating can be adjusted by the proportion of polymethylhydrosiloxane (PMHS) and vinyltrimethylsilane (VTMS). The results of ice adhesion force test show that the ice adhesion force on the coating is related to the cross-link density of the coating. With the increase of the cross-link density from 234 ± 43 mol/m3 to 1358 ± 31 mol/m3, the ice adhesion force decreases from 51.15 ± 4.7 kPa to 27.8 ± 3.9 kPa. The lower ice adhesion force corresponds to a higher anti-icing performance. With the addition of silicone oil, the ice adhesion force on the coating can be further reduced to 9.2 ± 1.2 kPa, indicating a further enhancement in the anti-icing performance. The results of icing/deicing cycle test show that, after icing/deicing for 30 cycles, the coating still exhibits efficient anti-icing performance.

Reduction of Ice Adhesion Using Surface Acoustic Waves: Nanoscale Vibration and Interface Heating Effects.

Ice accumulation causes great risks to aircraft, electric power lines, and wind-turbine blades. For the ice accumulation on structural surfaces, ice adhesion force is a crucial factor, which generally has two main sources, for exampple, electrostatic force and mechanical interlocking. Herein, we present that surface acoustic waves (SAWs) can be applied to minimize ice adhesion by simultaneously reducing electrostatic force and mechanical interlocking, and generating interface heating effect. A theoretical model of ice adhesion considering the effect of SAWs is first established. Experimental studies proved that the combination of nanoscale vibration and interface heating effects lead to the reduction of ice adhesion on the substrate. With the increase of SAW power, the electrostatic force decreases due to the increase of dipole spacings, which is mainly attributed to the SAW induced nanoscale surface vibration. The interface heating effect leads to the transition of the locally interfacial contact phase from solid-solid to solid-liquid, hence reducing the mechanical interlocking of ice. This study presents a strategy of using SAWs device for ice adhesion reduction, and results show a considerable potential for application in deicing.

Non-fluorinated and durable photothermal superhydrophobic coatings based on attapulgite nanorods for efficient anti-icing and deicing

Superhydrophobic coatings are promising for anti-icing, however, preparation of those with both excellent passive anti-icing and active deicing functions is very challenging, especially via eco-friendly approaches. Here, we report non-fluorinated and durable photothermal superhydrophobic coatings based on natural attapulgite nanorods for efficient anti-icing and deicing. The attapulgite nanorods were coated with polypyrrole by oxidation polymerization of pyrrole, and then coated with hexadecyl polysiloxane by hydrolytic condensation. The photothermal superhydrophobic coatings were prepared by spray-coating the mixture of the modified attapulgite suspension and a silicone resin onto aluminum plates. The coatings show (i) excellent superhydrophobicity (water contact angle = 162.7°, sliding angle = 2.7°) due to the three-tier hierarchical micro-/nanostructure and low surface energy, (ii) excellent photothermal effect (increase in surface temperature to 70 °C in 3 min under 1 sun) due to the enlarged surface area of polypyrrole exposed to sunlight by the hierarchical micro-/nanostructure, and (iii) good mechanical, chemical and thermal stability. Consequently, in both simulated and outdoor environments, the coatings show excellent anti-icing and deicing performances, e.g., significantly prolonged water freezing time, greatly reduced ice adhesion force, fast photothermal deicing and efficient long-term (4 weeks) outdoor anti-icing/deicing. The coatings are very promising for practical applications due to the excellent performances and eco-friendly method.

Novel superhydrophobic carbon fiber/epoxy composites with anti-icing properties

In this study, novel carbon fiber/epoxy (CF/EP) composites with anti-icing properties were made using a combination of octadecylamine modification and hard templating. First, the octadecylamine-modified epoxy resin was sprayed on the surface of CF/EP prepreg. Hierarchical micro/nanostructures were formed on the surfaces of the composites through hot pressing with aluminum templates that had been modified by sandblasting and anodizing. The resulting composites were superhydrophobic, with static contact angles of up to 155° and sliding angles as low as 8°. Superhydrophobicity was maintained after abrading with 400 grit SiC sandpaper. The anti-icing properties of the composites were quantified by measuring droplet freezing time and ice adhesion force. Compared to untreated CF/EP, the surface treatments used here increased the time to freeze a 5 μL surface droplet from 76 to 640 s at − 20 °C, and reduced ice adhesion strength from roughly 74 kPa to 50 kPa.

Studying the Bulk and Contour Ice Nucleation of Water Droplets via Quartz Crystal Microbalances.

Due to the stochastic and time-dependent character of the ice embryo formation and growth (i.e., a process that can be analyzed statistically, but cannot be predicted precisely), the heterogeneous ice nucleation on atmospheric aerosols or macroscopic solid surfaces is still shrouded in mystery, regardless of the extremely active research and exponential progress within this scientific field. For instance, whether the icing appears from outside-in or inside-out is a subject of intense controversy, with practicability in designing passive icephobic coatings or improving the effectiveness of the cryopreservation technologies. Here, we propose an artful technique for quantitative analysis of the different modes of water freezing using super-nonwettable soot-coated quartz crystal microbalances (QCMs). To achieve this goal, a set of 5 MHz QCMs are loaded one at a time with a 50 μL droplet, whose bulk or contour solidification is detected in real-time. The obtained experimental results show that our sensor devices recognize explicitly if the ice nuclei form predominantly at the liquid–solid interface or spread along the droplet’s entire outer shell by triggering individual reproducible responses in terms of the direction of signal evolution in time. Our results may serve as a foundation for the future incorporation of QCM devices in different freezing assays, where gaining information about the ice adhesion forces and ice layer’s thickness is mandatory.

Hybrid Modification of Unsaturated Polyester Resins to Obtain Hydro- and Icephobic Properties

Ice accumulation is a key and unsolved problem for many composite structures with polymer matrices, e.g., wind turbines and airplanes. One of the solutions to avoid icing is to use anti-icing coatings. In recent years, the influence of hydrophobicity of a surface on its icephobic properties has been studied. This solution is based on the idea that a material with poor wettability maximally reduces the contact time between a cooled drop of water and the surface, consequently prevents the formation of ice, and decreases its adhesion to the surface. In this work, a hybrid modification of a gelcoat based on unsaturated polyester resin with nanosilica and chemical modifiers from the group of triple functionalized polyhedral oligomeric silsesquioxanes (POSS) and double organofunctionalized polysiloxanes (generally called multi-functionalized organosilicon compounds (MFSC)) was applied. The work describes how the change of modifier concentration and its structural structure finally influences the ice phobic properties. The modifiers used in their structure groups lowered the free surface energy and crosslinking groups with the applied resin, lowering the phenomena of migration and removing the modifier from the surface layer of gelcoat. The main studies from the icephobicity point of view were the measurements of ice adhesion forces between modified materials and ice. The tests were based on the measurements of the shear strength between the ice layer and the modified surface and were conducted using a tensile machine. Hydrophobic properties of the obtained nanocomposites were determined by measurement of the contact angle and contact angle hysteresis. As the results of the work, it was found that the modification of gelcoat with nanosilica and multi-functionalized silicone compounds results in the improvement of icephobic properties when compared to unmodified gelcoat while no direct influence of wettability properties was found. Ice adhesion decreased by more than 30%.

Experimental study on ice adhesion forces of the copper plates with specific contact angle and roughness

Experimental ice adhesion force measurements were conducted on the surfaces of the copper plates with specific contact angle and roughness. The ice adhesion forces formed by cooling the surfaces of the copper plates to different temperatures were compared and analyzed. The effect of frosting on the surfaces of the copper plates was eliminated, and the same cooling rate was adopted to strictly control the number of bubbles trapped in the ice and the formation conditions of fine cracks at the ice-copper interface. The duration of freezing was defined, and the changing law of the recalescence point and the duration of freezing was explored. The results show that the ice adhesion forces measured on the surfaces of the copper plates are larger when the target temperatures of the copper plates are −25 °C and −20 °C, while the ice adhesion forces measured at the target temperature of −10 °C are minimal. The experimental results with the target temperature of −25 °C are the most dispersed and covered the most extensive range. The maximum and minimum values of ice adhesion forces in this case are 11.28 N and 7.58 N, respectively, and the difference between them is 3.7 N.

Anti-frosting and defrosting performance of chemically modified super-nonwettable carbon soot coatings

The inherent hydrophilicity of a variety of heat exchanging industrial appliances, including air-conditioners, refrigerators or heat pumps, is a highly-beneficial platform for the accumulation of frost at negative surface temperatures, dramatically aggravating the efficient device operation in terms of heat transfer and energy consumption. Here, we introduce experimental data from pioneering research on the frosting/defrosting behavior of chemically modified super-nonwettable soot—one of the very few materials providing scalability, satisfactory mechanical durability, icephobic and anti-bioadhesion properties simultaneously. The analysis of the anti-frosting/defrosting performance of three groups of soot coatings, obtained by treating the pristine samples with alcohol, fluorocarbon or silver hydrogen fluoride, reveals that the frost incipiency on the soot can be efficiently controlled by tailoring its chemistry and porosity. In turn, the super-nonwettable material is capable of delaying the onset of vapor condensation and frosting to supercooling degrees of 8.4 °C and 15.8 °C, accordingly, and maintaining relatively large frost-free halos up to −20 °C. Moreover, the onset of soot defrosting is accelerated by a factor of 35 compared to a bare Cu substrate, demonstrating extremely low ice adhesion forces and strong potential of the soot coatings for passive icing protection of many cryogenic facilities.

Toward Passive Defrosting with Heterogeneous Coatings

A large amount of energy is lost in industrial active deicing. One problem is that water retention on the surface after ice melting decreases the overall heat-transfer coefficient by up to 20%. The Miljkovic group utilizes heterogeneous biphilic surfaces to enhance defrosting performance. They avoid water retention as the slush is rapidly drawn toward the hydrophilic regions before it completely melts.

Superhydrophobic surfaces with flake-like structures and lubricant-infused composite surfaces to enhance anti-icing ability

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.