Anti-icing Coatings Research Articles

SiO2/polydopamine photothermal superhydrophobic coating with good anti-icing performance

The icing phenomenon has become a safety hazard for the normal operation of equipment. In this work, we report a strategy for simply obtaining photothermal anti-icing coatings by spraying acrylic resin, polydimethylsiloxane and polydopamine modified SiO2 particles on a steel plate substrate. The prepared icephobic AR/PDMS/SiO2@PDA composite coating not only has excellent superhydrophobicity (WCA = 162°). It also shows good anti- and de-icing performances. The superhydrophobic surface was able to delay freezing for 614 s at −20°C, and the ice adhesion of its surface was 54 kPa. In addition, PDA-modified SiO2 particles endow the coating with photothermal properties. Under the irradiation of simulated sunlight, the photothermal coating rapidly reached 61°C within 3 min, and the ice droplets completely melted in 155 s. Besides, it's able to withstand a wide range of chemical attacks and mechanical impacts. After 15 icing-de-icing cycles and 40 sandpaper abrasions cycles test, the prepared coatings can still maintain remarkable ice-removal performance, demonstrating excellent mechanical robustness and stability in harsh environments.

Fabrication of a water repellent comb-like WPU with excellent and sustainable anti-icing performance

Surface functional materials have aroused extensive attention due to tremendous application foreground in the anti-icing technology. However, durability and longevity are still critical problems that restrict their practical applications. In this work, a sustainable water-repellent surface was facilely constructed through comb-like WPU of crystalline octadecyl pendant groups. Because of octadecyl crystals tilting on the surface, the comb-like WPU exhibit dynamic water-repellent properties, which are mainly related to laying-down phase of crystals. Meanwhile, the surface wetting behavior is reversible switching between the sliding state and the pinning state due to phase transition, and the surface self-replenishing occurs in this process. Besides, on the basis of excellent adhesion to several substrates, these comb-like WPU make the crystallization temperature of water decreased by 9 °C approximately, and the ice adhesion strength (τice) before and after 150 abrasion cycles maintain only 3 kPa at −20 °C, exhibiting remarkable and regenerable anti-icing and deicing properties. Importantly, the transformation from laying-down phase to standing-up phase of crystals generates the successive deicing effect of interfacial slippage and micro-cracks, resulting in low τice below 20 kPa after continuous 100 icing/deicing cycles. These findings provide a facile way to design a promising surface material for enhancing endurance of anti-icing coatings.

Efficiently all-weather anti-icing and de-icing coatings enabled by polyaniline microcapsules encapsulated phase change materials

Photothermal superhydrophobic coatings are one of the most promising anti-icing/de-icing materials. However, the intermittence of light energy limits the application of photothermal energy conversion technologies when continuous de-icing is required. Herein, an innovative solution for the integration of photothermal effect and phase change thermal storage was proposed. In this work, an efficient anti-icing/de-icing coating was successfully fabricated based on multifunctional polyaniline microcapsule encapsulating butyl stearate (BS). Benefiting from the heat storage capacity of BS in the microcapsule, the coating could achieve all-weather anti-icing capability. Under the condition of −20 °C, the freezing time of water droplets on the coating with only 10 wt% microcapsules was delayed by about 12.6 times compared to the blank coating. At the same time, under simulated dark conditions, the freezing time of water droplets could be delayed by about 14.1 times. Moreover, owing to the thermal conductivity and high solar energy exploitation, polyaniline endowed the coating with outstanding photothermal de-icing performance, presenting the superiority of outdoor applications. Under NIR (200 mW/cm2) illumination, the melting time of water droplets was reduced to 18 s, which was nearly 10 times faster than that on the blank coating. Moreover, the polyaniline microcapsules also possessed outstanding anticorrosion property, which was particularly attractive for mental coating applications. The combined properties of this all-weather anti-icing and de-icing coating could render it a promising contender for challenging outdoor applications.

TiN/acetylene black composite coatings: Enhanced durability and superhydrophobicity for all-day anti-Icing applications

Current advancements in anti-icing coatings emphasize the integration of photothermal, electrothermal, and superhydrophobic features to significantly enhance de-icing efficiency. However, these multifaceted coatings often involve intricate preparation methods and costly materials, making them susceptible to damage and reduced durability. This research aims to overcome these challenges by combining active and passive anti-icing principles to achieve full-time efficient anti-icing. A novel strategy is devised to modify the wettability of epoxy resins by grafting a fluorinated oligomer using a curing agent bridging technique. By utilizing micron-sized Titanium Nitride (TiN) and nanosized Acetylene Black fillers within a fluorine-modified epoxy resin, applied through a simple spray technique, the resulting coating exhibits excellent photothermal, electrothermal, and superhydrophobic properties. Evaluations confirm the coating’s robust mechanical durability for extended operational use and its stabilized effectiveness in photothermal and electrothermal de-icing. Notably, this approach maintains electrical conductivity by eliminating the filler hydrophobic modification, also enhancing the mechanical performance of nanocarbon-based multifunctional anti-icing coatings. Moreover, it simplifies the manufacturing process, reduces cost of coating materials, and enables broad application across various substrate surfaces.

Innovative ice mitigation: Exploring the potential of choline-based deep eutectic solvents and ionic liquids synergies

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

Anti-icing transparent coatings modified with bi- and tri-functional octaspherosilicates for photovoltaic panels

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

Robust anti-icing double-layer superamphiphobic composite coatings for heat exchangers

The formation and accumulation of ice on the heat exchangers of air conditioners significantly reduce the performance issues, as well as the stability and heating efficiency. Superhydrophobic anti-icing coatings passively achieve multifunctional anti-icing properties by minimizing water droplet contact and promoting Cassie ice formation. However, long-term performance in frigid environments remains challenge for these coatings due to limitations in anti-icing durability and mechanical properties. Herein, a double-layer polymer-SiC/F-SiO2 superamphiphobic composite coating is developed. The bottom layer comprises a polymer PAI and SiC composite, and the top layer consists of F-SiO2. The composite coating demonstrates superior performance in simultaneous frost prevention, low ice adhesion, easy frost removal, exceptional mechanical strength, and long-lasting anti-icing durability. Our developed double-layer coating exhibits low ice adhesion strength down to 9.2 kPa, remarkable mechanical resilience against scratching and flushing, and delayed frost properties. These superior anti-icing properties, manifested by both lower adhesion strength and improved frost repellency, lead to a doubling of frosting time and the easier removal of ice on coated heat exchangers compared to traditional units. The development of this novel superamphiphobic composite coating provides a practical approach to creating durable anti-icing materials, leading to significant improvements in air conditioner performance.

Fabrication of SiO2/PDMS/EP superhydrophobic coating for anti-icing

In low-temperature environments, the condensation and icing phenomena of water molecules on material surfaces may adversely affect the functionality and durability of various products, so it is critical to improve the anti-icing properties of material surfaces. In this study, the anti-icing mechanism of superhydrophobic coatings was analyzed based on the surface wettability theory, and SiO2/PDMS/EP superhydrophobic coating was fabricated by the spraying method. The surface wettability, surface micro-morphology, and surface chemical composition of the coating was characterized, and the stability of the coating as well as the anti-icing properties were investigated. The results show that the SiO2/PDMS/EP superhydrophobic coating sprayed on the Al-based surface has a contact angle of 163.3° and a sliding angle of 4°, and the coating maintains excellent superhydrophobicity at a low temperature of -15°. This coating can significantly delay the freezing time and temperature of droplets on its surface, reduce the shear force and natural deicing time required to remove surface ice, and exhibit excellent anti-icing performance. The excellent anti-icing durability of the coating was demonstrated by the icing-deicing cycle experiment. Subsequently, the anti-frosting performance was further investigated, and the results showed that it effectively slowed down the speed of frost formation. Therefore, the superhydrophobic coating fabricated in this study is suitable for a wide range of working conditions and has potential practicality. It also provides experimental guidance for the application of anti-icing coatings on Al surfaces.

Exploring hydrophobic surface modifications in silica and alumina nanomaterials✰

Superhydrophobic materials have attracted significant attention in various applications including leather manufacturing, water-resistant textiles, self-cleaning surfaces, anti-icing coatings, etc... In the present work, we elucidated the functionalization of silica nanoparticles using isostearic acid, a cheap, non-toxic and highly branched molecule, substituting the conventional toxic fluorinated molecules, in comparison with the alumina counterpart and commercial hydrophobic materials. In this respect, the performance of isostearic acid is compared to the commercially used hexamethyldisilazane, a rigid and bulky moiety of high toxicity and environmental persistence. The functionalized surfaces were characterized by infrared spectroscopy, nuclear magnetic resonance spectroscopy, N2 physisorption, field emission scanning electron microscopy, and thermogravimetric analysis. Microgravimetric and microcalorimetric measurements were also used to describe the surface interaction with water, while the water-repellency at the macroscopic level was monitored through contact angle measurements. Both silica surfaces functionalized with isostearic acid and hexamethyldisilazane show a collective superhydrophobic behavior, but the flexibility of the isostearic acid chains, bonded in low surface density (0.7 units per nm2) through alkyl chains, allow for diffusion of water vapor at the molecular level, while this is not observed in the hexamethyldisilazane case due to the smaller molecular size of the rigid moiety, coupled to a higher surface density (3.5 units per nm2). The results revealed that a material does not necessarily expose micro-nano hierarchical structures to reach an ultimate waterproof capability with a contact angle higher than 150°.

Early-Stage Ice Detection Utilizing High-Order Ultrasonic Guided Waves.

Ice detection poses significant challenges in sectors such as renewable energy and aviation due to its adverse effects on aircraft performance and wind energy production. Ice buildup alters the surface characteristics of aircraft wings or wind turbine blades, inducing airflow separation and diminishing the aerodynamic properties of these structures. While various approaches have been proposed to address icing effects, including chemical solutions, pneumatic systems, and heating systems, these solutions are often costly and limited in scope. To enhance the cost-effectiveness of ice protection systems, reliable information about current icing conditions, particularly in the early stages, is crucial. Ultrasonic guided waves offer a promising solution for ice detection, enabling integration into critical structures and providing coverage over larger areas. However, existing techniques primarily focus on detecting thick ice layers, leaving a gap in early-stage detection. This paper proposes an approach based on high-order symmetric modes to detect thin ice formation with thicknesses up to a few hundred microns. The method involves measuring the group velocity of the S1 mode at different temperatures and correlating velocity changes with ice layer formation. Experimental verification of the proposed approach was conducted using a novel group velocity dispersion curve reconstruction method, allowing for the tracking of propagating modes in the structure. Copper samples without and with special superhydrophobic multiscale coatings designed to prevent ice formation were employed for the experiments. The results demonstrated successful detection of ice formation and enabled differentiation between the coated and uncoated cases. Therefore, the proposed approach can be effectively used for early-stage monitoring of ice growth and evaluating the performance of anti-icing coatings, offering promising advancements in ice detection and prevention for critical applications.

Reducing Ice Adhesion to Polyelectrolyte Surfaces by Counterion-Mediated Nonfrozen Hydration Water.

Hydrophilic anti-icing coatings can be energy-effective passive solutions for combating ice accretion and reducing ice adhesion. However, their underlying mechanisms of action remain inferential and are ill-defined from a molecular perspective. Here, we systematically investigate the influence of the counterion identity on the shear ice adhesion strength to cationic polymer coatings having quaternary alkyl ammonium moieties as chargeable groups. Temperature-dependent molecular information on the hydrated polymer films is obtained using total internal reflection (TIR) Raman spectroscopy, complemented with differential scanning calorimetry (DSC) and ellipsometry. Ice adhesion measurements show a pronounced counterion-specific behavior with a sharp increase in adhesion at temperatures that depend on the anion identity, following the order Cl- < F- < SCN- < Br- < I-. Linked to the freezing of hydration water, the specific ordering results from differences in ion pairing and the amount of water present within the polymer film. Moreover, similar effects can be promoted by varying the cross-linking density in the coating while keeping the anion identity fixed. These findings shed new light on low ice adhesion mechanisms and may inspire novel approaches for improved anti-icing coatings.

Facile Preparation of Impalement Resistant, Mechanically Robust and Weather Resistant Photothermal Superhydrophobic Coatings for Anti-/De-icing.

Photothermal superhydrophobic coatings hold great promise in addressing the limitations of conventional superhydrophobic anti-icing coatings. However, developing such coatings with excellent impalement resistance, mechanical robustness and weather resistance remains a significant challenge. Here, we report facile preparation of robust photothermal superhydrophobic coatings with all the above advantages. The coatings were prepared by spraying a dispersion consisting of fluorinated silica nanoparticles, a silicone-modified polyester adhesive and photothermal carbon black nanoparticles onto Al alloy plates followed by thermal curing. Thermal curing caused migration of perfluorodecyl polysiloxane from within the coatings to the surface, effectively maintaining a low surface energy despite the presence of the adhesive. Therefore, combined with the hierarchical micro-/nanostructure, dense yet rough nanostructure, adhesion of the adhesive and chemically inert components, the coatings exhibited remarkable superhydrophobicity, impalement resistance, mechanical robustness and weather resistance. Furthermore, the coatings demonstrated excellent photothermal effect even in the -10 °C, 80 % relative humidity and weak sunlight (0.2 sun) environment. Consequently, the coatings showed excellent passive anti-icing and active de-icing performance. Moreover, the coatings have good generalizability and scalability. We are confident that this study will accelerate the practical implementation of photothermal superhydrophobic coatings.

Anti-icing application of superhydrophobic coating on glass insulator

Insulators, as important components in transmission lines, are prone to disturb the safe running of the power system by the ice accumulation on surfaces. Traditional anti-icing coatings are difficult to practically apply to insulators. Here, superhydrophobic (SHP) coatings were fabricated on the glass insulator surface by spraying. We studied microstructure, wettability, water droplet bouncing behavior, and anti-glaze icing properties of SHP coating. The results demonstrated that SHP coatings had micro-nano rough structures. The excellent superhydrophobicity (contact angle of 165.2° and sliding angle of 3.7°) was achieved. The water droplet was easily adhered to the surface of the glass insulators. At the same time, individual water droplets could bounce away from the surface after impacting the SHP coating. In the glaze environment, water droplets sprayed onto the SHP coating merged with each other and slid off the surface. These significantly reduce the likelihood of freezing. Furthermore, the SHP coating could dramatically delay the glaze icing and decrease the icing area. The icing weight and icicle length were smaller than glass insulators. The SHP coatings prepared in this work display great potential for the anti-icing of glass insulators.

A simple fabrication of liquid-like polydimethylsiloxane coating for resisting ice adhesion.

The rapid realization of efficient anti-icing coatings on diverse substrates is of vital value for practical applications. However, current approaches for rapid preparations of anti-icing coatings are still deficient regarding their surface universality and accessibility. Here, we report a simple processing approach to rapidly form icephobic liquid-like polydimethylsiloxane (PDMS) brushes on various substrates, including metals, ceramics, glass, and plastics. A poly(dimethylsiloxane), trimethoxysilane is applied as a reactant under the catalysis of a minimal amount of acid formed by hydrolysis of dichlorodimethylsilane. With such an advantage, this approach is approved to be applicable of coating metal surfaces with less corrosion. The distinctive flexibility of the PDMS chains provides a liquid-like property to the coating showing low contact angle hysteresis and ice adhesion strength. Notably, the ice adhesion strength remains similar across a wide temperature window, from -70 to -10 °C, with a value of 18.4kPa. The PDMS brushes demonstrate perfect capability for resisting acid and alkali corrosions, ultra-violet degradation, and even tens of icing/deicing cycles. Moreover, the liquid-like coating can also form at supercooling conditions, such as -20 °C, and shows an outstanding anti-icing/deicing performance, which meets the in situ coating reformation requirement under extreme conditions when it is damaged. This instantly forming anti-icing material will benefit from resisting instantaneous ice accretion on surfaces under extremely cold conditions.

To be or not to be a hydrophobic matrix? the role of coating hydrophobicity on anti-icing behavior and ions mobility of ionic liquids

The demand for anti-icing coatings to endure extremely low temperatures is substantial. Despite the innovative pioneering research on the anti-icing potential of ionic liquids (ILs), the development of such coatings is still in its infancy. Our study investigates how matrix hydrophobicity influences mobility of ILs at subzero temperatures and, consequently, their anti-icing behavior. Wettability results highlight the key role of IL anion hydrophobicity. Dielectric spectroscopy distinguishes ion mobility in the coatings at low temperatures. We also investigate how varying crosslink density affects ion mobility by measuring the water absorbency. Higher mobility of released ILs from the coatings at subzero was confirmed by their presence in water solutions, validated with UV–vis spectroscopy, and resulted in increased ionic conductivity. Differential scanning calorimetry and experimental setups were employed to assess ice formation temperature, time, and ice adhesion strength. Notably, surfaces containing IL exhibited a remarkable reduction in ice formation temperature to –23.5 ℃ and achieved an exceptionally low ice adhesion strength (∼15 kPa), attributed to the formation of a quasi-liquid layer (QLL). Solid-state NMR spectroscopy provided confirmation of the existence of QLL at the interface. Ice adhesion strength of coatings was examined against accelerated weathering, icing/de-icing cycles, as well as endurance against frost formation under freeze–thaw. Our findings underscore the significance of selecting the right matrix with regards to hydrophobicity and ILs when designing coatings for subfreezing applications.

Durable anti-icing coating with stability based on self-regulating oil storage layer

In recent years, slippery liquid-infused porous surfaces (SLIPSs) have emerged as a potential alternative to superhydrophobic surfaces (SHSs) due to their exceptional anti-icing properties. However, the current challenge lies in the significant lubricant consumption of SLIPSs, which poses a major obstacle to coating durability. In this study, we developed a durable anti-icing coating with stability (DASS), which combines SHSs and SLIPSs. By incorporating high adsorption particles and low cross-linking density rubber into the oil storage layer, the coating achieves an increased oil storage capacity while effectively inhibiting lubricant loss. Additionally, a superhydrophobic layer is introduced on the surface to ensure surface lubrication and prevent lubricant depletion. The three-layer structure enables the coating to maintain a low τice (<20kPa) during 30 icing/deicing cycles, showcasing superior de-icing durability compared to conventional anti-icing coatings. Interestingly, the original anti-icing properties of the coating can be restored through external oil replenishment. Furthermore, this coating exhibits excellent resistance against fouling, mechanical stress, chemical exposure, temperature variations, and weathering effects, making it highly suitable for practical applications in anti-icing coatings.

Bioinspired durable interpenetrating network anti-icing coatings enabled by binders and hydrophobic-ion specific synergies

Designing a coating with a comprehensive range of anti-icing properties is a difficult challenge in the current complex and variable icing environment. Bionic anti-icing coatings have received widespread attention in recent years, but their exposure to mechanical damage conditions tends to result in insufficient durability. This work proposes a novel approach inspired by the antifreeze proteins (AFPs) found in fish, wherein a durable interpenetrating coating with excellent anti-icing and deicing performance is designed by combining a fluorinated amphiphilic ionic polymer with a biomimetic binder. The incorporation of hydrophobic fluorinated chain segments and amphiphilic ionic chain segments effectively inhibits ice nucleation (DT = 2010 s, TIN = − 22.1 °C), slows down ice propagation, and reduces ice adhesion (τ = 22.2 kPa) through the synergistic effect of hydrophobicity and ionic specificity. Furthermore, the addition of a bionic binder to create an interpenetrating network enhances the mechanical properties and anti-icing durability of the coating. Moreover, it can further function as anti-fogging, self-cleaning, and antibacterial for glass surfaces, demonstrating significant potential in the new generation of optical and medical devices.

Silicone elastomers and the Persson-Brener adhesion model.

Many modern anti-icing and anti-fouling coatings rely on soft, low surface energy elastomeric materials such as polydimethylsiloxane for their functionality. While the low surface energy is desirable for reducing adhesion, very little work considers the larger contribution to adhesive failure caused by the viscoelastic nature of elastomers. Here we examine several different siloxane elastomers using a JKR adhesion test, which was operated over a range of different speeds and temperatures. Additionally, we characterize the dynamic mechanical modulus over a large range of frequencies for each material. We note that surface energies of the materials are all similar, but variation in adhesion strength is clear in the data. The variation at low speeds is related to elastomer architecture but the speed dependence itself is independent of architecture. Qualitative correlations are noted between the JKR adhesion measurements and the dynamic moduli. Finally, an attempt is made to directly compare moduli and adhesion through the recent Persson-Brener model. Approximations of the model are shown to be inaccurate. The full model is found to be accurate at low speeds, although it fails to precisely capture higher speed behaviour.

Fabrication of Superhydrophobic Coatings by Using Spraying and Analysis of Their Anti-Icing Properties

Ice accumulation on glass insulators is likely to cause faults such as flashover, tripping and power failure, which interfere with the normal operation of the power grid. Accordingly, superhydrophobic coatings with great anti-icing potential have received much attention. In this study, three superhydrophobic coatings (PTFE, Al2O3 and SiO2) were successfully prepared on glass surfaces by using one-step spraying. The microscopic morphology, wettability, anti-icing and anti-glaze icing properties of the superhydrophobic coatings were comparatively analyzed. The results indicated that the PTFE coating had a densely distributed rough structure, showing a contact angle of 165.5° and a sliding angle of 3.1°. The water droplets on the surface could rebound five times. Compared with the Al2O3 and SiO2 coatings, the anti-icing performance of the PTFE coating was significantly improved. The freezing time was far more than 16 times that of glass (4898.7 s), and the ice adhesion strength was 9 times lower than that of glass (27.5 kPa). The glaze icing test in the artificial climate chamber showed that the icing weight of the PTFE coating was 1.38 g, which was about 32% lower than that of the glass. In addition, the icing/melting and abrasion cycles destroyed the low-surface-energy substances and nanostructures on the surface, leading to the degradation of the anti-icing durability of the PTFE coatings. However, the PTFE coating still maintained excellent hydrophobicity and anti-icing properties after UV irradiation for up to 624 h. The superhydrophobic coatings prepared in this work have promising development prospects and offer experimental guidance for the application of anti-icing coatings on glass insulators.

Graphite flakes based anti-icing coatings

Graphite flakes based anti-icing coatings