Search Results (73)

Freezing rain poses a substantial hazard to the operation and safety of unmanned aerial vehicles (UAVs) in cold-weather environments. In the present study, a comprehensive experimental campaign was conducted to investigate the effect of surface icephobicity on ice accretion and shedding from rotating UAV propellers under freezing-rain conditions. A novel, durable, slippery liquid-like surface (SLLS) coating, characterized by low contact-angle hysteresis and low ice adhesion, is utilized as a passive strategy for UAV icing mitigation. The coating was assessed through wettability and ice-adhesion measurements, phase-locked high-speed imaging of supercooled large-droplet impingements, rotating-propeller ice accretion experiments, accelerated rain erosion testing, and surface-topography characterization. The measurement results revealed distinct normal and oblique droplet impingement regimes and demonstrated that the evolving leading-edge ice geometry substantially altered droplet deformation, liquid redistribution, and subsequent ice growth. Compared with the uncoated, baseline propeller, the SLLS-coated propeller was found to promote earlier ice shedding and reduce the ice-induced power consumption by approximately 36%. These findings highlight the potential of SLLS coatings as a promising strategy for UAV propeller icing protection to ensure safer and more efficient UAV operations under adverse weather conditions. Full article

Ice accumulation on aircraft surfaces severely affects aerodynamic performance by increasing drag and reducing lift, leading to stall conditions. Conventional thermal and pneumatic anti-/de-icing systems, although widely used, have some disadvantages, including high cost, inefficiency, and environmental unsustainability. Hydrophobic and icephobic coatings have emerged as a promising alternative to reduce ice adhesion and delay ice formation. This paper reviews the use of silane agents in epoxy-based coatings, incorporating functional additives such as natural fibers, quantum dots, and nanoparticles, to enhance hydrophobicity. Results demonstrated that the combination of silanes and functional additives affects surface features and wettability, improving hydrophobicity. These case studies show the potential of this approach in the development of coatings for advanced aircraft ice-protection applications. Full article

This study presents the development and experimental evaluation of an impregnation composition for cement concrete pavements aimed at improving ice-phobic performance while preserving tire–pavement adhesion characteristics. The formulation is based on a combination of keratin-containing raw materials and water-soluble polymer components. Optimization showed that a polymer concentration of 2.5% reduces concrete water absorption by 49–53% compared with untreated specimens. Freezing tests conducted at temperatures of 0 to −5 °C demonstrated an additional reduction in water absorption of treated specimens by 33–40% relative to uncoated concrete and improved resistance to ice formation. The influence of the impregnation on tire–pavement interaction was assessed using a direct shear method, revealing minor changes in friction coefficients of up to ~6% for polished and less than 1% for rough surfaces, remaining within acceptable safety limits. Wear resistance was evaluated through rolling tests with model vehicle wheels, where laboratory abrasion occurred after several thousand loading cycles, while probabilistic correction accounting for trajectory variability indicated an extension of service life to the order of tens of thousands of vehicle passes. The results confirm the potential of the keratin–polymer impregnation as an effective approach for enhancing the durability and operational safety of concrete pavements in cold climates. Full article

Ice accretion on aircraft, wind-turbine blades, power networks, civil infrastructure, and exposed sensors poses severe safety risks and economic costs. Passive icephobic surfaces mitigate icing by delaying heterogeneous nucleation, altering droplet impact/solidification and wetting transitions, and/or weakening the ice–substrate bond so that accreted ice sheds under modest aerodynamic, gravitational, or vibrational loads. This review synthesizes recent progress using a unified mechanism framework linking (i) nucleation and early freezing, (ii) droplet dynamics during impact or condensation/frosting, and (iii) ice accretion and removal governed by interfacial fracture. Smooth low-surface-energy coatings, textured (superhydrophobic) surfaces, slippery liquid-infused porous surfaces (SLIPS), and low-interfacial-toughness strategies are critically compared in terms of achievable performance ranges, failure modes, durability limits, fabrication scalability, and test-method dependence. Ice-adhesion measurement approaches (push-off, pull-off/tensile, centrifugal) are assessed and a minimum reporting checklist is provided to improve comparability. Case studies across aviation, wind energy, power infrastructure, sensors, and emerging civil-engineering coatings highlight that durability and scale-dependent failure modes remain the dominant barriers to durable, energy-free icing mitigation. The review concludes with priorities for eco-friendly chemistries, self-healing or renewable layers, standardized testing/reporting, and data-driven (machine learning-assisted) optimization to accelerate translation into durable passive ice-mitigation technologies. Full article

Icing on surfaces presents a significant challenge across various technological fields, with added weight and operational interference impacting aircraft wings, wind turbine blades, and electrical equipment. While electrothermal methods effectively accelerate ice melting through the Joule effect, their substantial cost and energy consumption necessitate careful consideration. In the past two decades, anti-icing and icephobic coatings have garnered significant interest due to advancements in nanomaterials and a deeper understanding of ice nucleation and adhesion. These coatings are designed to prevent water droplet adhesion, delay freezing, and/or reduce ice adhesion, without the need for additional energy. Moreover, the combination of active Ice Protection Systems with passive coatings could prevent ice formation with an improved energy efficiency and reduced CO₂ emissions. Aligned with this aim, this study focuses on the development of anti-icing coatings, detailing the selection and characterization of the materials used in the coating formulations, including their chemical and physical properties. Subsequently, the experimental results are presented and analyzed, focusing on the characterization and anti-icing performance of the fabricated coatings through a series of tests. Finally, it concludes with a discussion of the key findings, useful for the formulation of advanced anti-icing coatings mainly for aeronautical applications. Full article

Several hydrophobic and superhydrophobic aluminum surfaces were prepared with a three-step process that includes chemical etching, a treatment in hot water and a further coating with fluoroalkysiloxane (FAS). By varying the concentration of the etchant, the immersion time in the etchant and the boiling time, surfaces characterized by different roughness were obtained, with a wettability ranging from hydrophobic to superhydrophobic values. The icephobic properties were tested and the results reveal important differences among the samples, related to the roughness of the surface and the etching and boiling treatment processes. Full article

Ice accumulation on exposed surfaces presents substantial economic and safety challenges across various industries. To overcome limitations associated with traditional anti-icing methods, such as the use of nanoparticles, this study introduces a novel and facile approach for fabricating superhydrophobic and anti-icing microstructures using cost-effective LCD 3D printing technology. The influence of diverse pillar geometries, including square, cylindrical, hexagonal, and truncated conical forms, was analyzed to assess their effects on the hydrophobic and anti-icing/icephobic performance in terms of wettability, ice adhesion strength, and icing delay time. The role of microstructure topography was further investigated through cylindrical patterns with varying geometric parameters to identify optimal designs for enhancing hydrophobic and icephobic characteristics. Furthermore, the effectiveness of surface functionalization using a low surface energy material was evaluated. Our findings demonstrate that the synergistic combination of tailored microscale geometries and surface functionalization significantly enhances anti-icing performance with reliable repeatability, achieving ice adhesion of 13.9 and 17.9 kPa for square and cylindrical pillars, respectively. Critically, this nanoparticle-free 3D printing and low surface energy treatment method offers a scalable and efficient route for producing high-performance hydrophobic/icephobic surfaces, opening promising avenues for applications in sectors where robust anti-icing capabilities are crucial, such as renewable energy and transportation. Full article

Guardrail concrete in cold regions frequently suffers from corrosion due to icing and solutions, significantly shortening the service life of the guardrail. This paper proposed a cement-based composite coating for concrete protection. The hydrophobic agent was synthesized using nano-silica, tetraethyl orthosilicate and perfluorodecyltrimethoxysilane and used for coating modification as an additive or by impregnation. Also, a commercial hydrophobic agent was used for comparison. The modified coating was characterized by wettability, mechanical properties, chemical stability and icephobicity tests. The results showed that the coating prepared with the synthetic hydrophobic agent presented a higher contact angle than that prepared with the commercial one during the above tests. Moreover, it featured excellent icephobicity by effectively delaying the time of icing on concrete and reducing the icing mass and ice adhesion strength. In addition, the hydrophobic agent used by impregnation was a better choice for concrete surface protection. Chemical composition and morphology analysis of the coating showed that hydrophobicity and icephobicity were mainly attributed to F-containing functional groups and rough structure with low surface energy. This study provided an application potential of modified cement-based composite coating for anti-/de-icing of guardrail concrete. Full article

The accumulation of ice on equipment exposed to low temperatures raises major efficiency and safety concerns. To overcome this challenge, various strategies have been developed to create icephobic surfaces. Their characterization typically relies on the measurements of icing delay time (IDT) or ice adhesion strength. However, the absence of standardized testing equipment leads to significant variability, as each research group employs different setups and conditions. This lack of standardization complicates the comparison of results and the evaluation of surface performance. Herein, we describe the development of a new reproducible test bench that allows for simultaneous measurement of ice adhesion strength and IDT under controlled humidity conditions. Results reveal that increasing humidity leads to higher adhesion and lower IDT values. This study highlights the critical influence of humidity and suggests that tests should be performed at low humidity levels in order to accurately assess the intrinsic icephobic properties of surfaces. Full article

Ice accumulation poses a significant hazard to aviation safety, particularly in cold weather conditions, as it can compromise aerodynamic performance, increase structural weight, and diminish lift, occasionally resulting in severe stall incidents. At present, such risks are managed through the use of energy-demanding active ice protection systems (IPSs), which operate either by inhibiting ice formation (anti-icing) or by removing existing ice (de-icing). Nonetheless, in the context of future sustainable aviation, there is a pressing need to develop IPSs with lower energy requirements. A promising approach involves hybrid IPSs that integrate conventional active systems with passive superhydrophobic or icephobic surface treatments, which are capable of preventing, delaying, or minimizing ice buildup. These systems offer the potential to substantially decrease the energy consumption and consequently the CO₂ emissions. Furthermore, in accordance with FAA regulations, active IPSs are not permitted to operate during takeoff and initial flight stages to prevent any reduction in engine thrust. These two reasons emphasize the critical importance of developing efficient coatings that, on the one hand, promote the mobility of water droplets, hereby preventing ice formation, as achieved by superhydrophobic surfaces, and on the other hand, facilitate ice detachment, as required for icephobic performance. In this context, the primary objective of the present work is to emphasize the icephobic properties of two superhydrophobic coatings. To achieve this, an extensive characterization is first conducted, including wettability, Surface Free Energy (SFE), and surface roughness, to confirm their superhydrophobic nature. This is followed by an assessment of their icephobic performance, specifically in terms of ice adhesion strength, with comparisons made against a commercial aeronautical coating. The results revealed a significant reduction in both the wettability and SFE of the developed coatings compared to the reference, along with a marked decrease in ice adhesion strength, thereby demonstrating their icephobic properties. Future activities will focus on the combination of coatings with active IPS in order to assess the energy efficiency under extensive icing conditions where both superhydrophobic and icephobic properties are required. Full article

Photothermal superhydrophobic surfaces with micro/nano-structured morphologies have emerged as promising candidates for anti-icing and deicing applications due to their exceptional water repellency and efficient solar-to-thermal conversion. These surfaces synergistically integrate the passive icephobicity of superhydrophobic coatings with the active heating capability of photothermal materials, offering energy-efficient and environmentally friendly solutions for sectors such as aviation, wind energy, and transportation. Hence, they have received widespread attention in recent years. This review provides a comprehensive overview of recent advances in photothermal superhydrophobic coatings, focusing on their anti-icing/deicing mechanisms, surface wettability, and photothermal conversion performance for anti-icing/deicing applications. Special emphasis is placed on material categories, including metals and their compounds, carbon-based materials, and polymers, analyzing their structural features and application effectiveness. Furthermore, the application of anti-icing/deicing in various fields is described. Finally, perspectives on future development are presented, including pursuing fluorine-free, cost-effective, and multifunctional coatings to meet the growing demand for innovative, sustainable anti-icing/deicing technologies. Full article

Within this study, a methodology for the numerical simulation of droplet freezing, including a micrometer texturized pattern, was developed. The finite volume method was then applied to simulate the behavior of water droplets. The procedure was divided into two processes: stabilization and freezing. In the stabilization step, the droplet was dropped onto the material surface and took an equilibrium shape. In the second step, additional energy equation and temperature boundary conditions were applied to perform freezing simulation. Based on the laser-texturized samples of polyurethane-coated metal substrates studied with freezing delay experiments, numerical models were generated, and droplet freezing simulations were performed. Three cases were studied—non-texturized and texturized with respectively linear and triangular patterns. The obtained simulation results of freezing time were compared with experimental measurements to evaluate the proposed methodology. The study revealed that despite the inability to predict accurate freezing delay time, the proposed methodology can be used to compare the freezing delay capabilities for different texturized patterns. Additionally, the proposed model renders it possible to analyze additional aspects of wetting and freezing of the droplet on rough surfaces, which may be helpful in understanding these processes. Full article

The development of superhydrophobic, waterproof, and breathable membranes, as well as icephobic surfaces, has attracted growing interest. Fluorinated polymers like PTFE or PVDF are highly effective, and previous research by the authors has shown that combining these polymers with electrospinning-induced roughness enhances their hydro- and ice-phobicity. The infusion of these electrospun mats with lubricant oil further improves their icephobic properties, achieving a slippery liquid-infused porous surface (SLIPS). However, their environmental impact has motivated the search for fluorine-free alternatives. This study explores polydimethylsiloxane (PDMS) as an ideal candidate because of its intrinsic properties, such as low surface energy and high flexibility, even at very low temperatures. While some published results have considered this polymer for icephobic applications, in this work, the electrospinning technique has been used for the first time for the fabrication of 95% pure PDMS fibers to obtain hydrophobic porous coatings as well as breathable and waterproof membranes. Moreover, the properties of PDMS made it difficult to process, but these limitations were overcome by adding a very small amount of polyethylene oxide (PEO) followed by a heat treatment process that provides a mat of uniform fibers. The experimental results for the PDMS porous coating confirm a hydrophobic behavior with a water contact angle (WCA) ≈ 118° and roll-off angle (αroll-off) ≈ 55°. In addition, the permeability properties of the fibrous PDMS membrane show a high transmission rate (WVD) ≈ 51.58 g∙m⁻²∙d⁻¹, providing breathability and waterproofing. Finally, an ice adhesion centrifuge test showed a low ice adhesion value of 46 kPa. These results highlight the potential of PDMS for effective icephobic and waterproof applications. Full article

This study examines the efficacy of icephobic polyurethane nanocomposite coatings in mitigating corrosion on an aluminum substrate. A titanium-based conversion coating is applied to modify the substrate, and the research focuses on optimizing the dual functionalities of icephobicity and anticorrosion within the polyurethane coatings while ensuring strong substrate adhesion. The coatings are formulated using fluoropolyol, isocyanate, and silica nanoparticles treated with polydimethylsiloxane. Surface properties are analyzed using contact angles, contact angle hysteresis measurements, and atomic force microscopy, and the coatings’ icephobicity is evaluated through differential scanning calorimetry, freezing time delay, ice adhesion under impact and non-impact conditions, and ice accretion tests. The corrosion resistance and adhesive strength of the coatings are assessed using electrochemical impedance spectroscopy and cross-cut tests, respectively. Increasing the concentration of silica nanoparticles to 10 wt.% increases contact angles to 167°, although the 4 wt.% coating produces the lowest contact angle hysteresis (3° ± 0.5°) and ice nucleation temperature (−23 °C). The latter coating is then applied to a substrate pretreated with a titanium/cerium-based conversion coating. This prepared surface maintains an ice adhesion of about 15 kPa after 15 icing/de-icing cycles and provides approximately 90 days of surface protection (|Z|_lf = 1.6 × 10⁹ Ω·cm²). Notably, the impedance value exceeds that of untreated substrates, underscoring the effectiveness of the titanium/cerium-based conversion coating in enhancing both corrosion resistance and coating adhesion to the substrate. Full article

Femtosecond laser processing significantly alters the surface structure and chemical composition, impacting its wetting properties. Post-treatments such as immersion in a hydrocarbon liquid (petrol) or storage in a vacuum can significantly reduce ice adhesion, making the surfaces interesting for anti-ice applications. This study investigates their durability against acetone, ethylene glycol, and UV radiation. The laser-structured surfaces were immersed in the respective liquids for up to 48 h. The results indicate limited durability of the superhydrophobic and icephobic layers when submerged in acetone and ethylene glycol, with more favorable results for petrol treatment than vacuum treatment. Similar results were obtained after 100 h of UV exposure, showing a decrease in superhydrophobic properties and an increase in ice adhesion. However, repeated vacuum treatments conducted after the chemical durability tests revealed the potential for partial recovery of the hydrophobic and icephobic properties. XPS analysis was performed throughout the experiments to evaluate changes in surface chemistry resulting from the post-laser treatments and the durability tests. Full article