A Holistic Solution to Icing by Acoustic Waves: De‐Icing, Active Anti‐Icing, Sensing with Piezoelectric Crystals, and Synergy with Thin Film Passive Anti‐Icing Solutions

Jin P., Yan X., Hoque M.J., Rabbi K.F., Sett S., Ma J., Li J., Fang X., Carpenter J., Cai S., Tao W., Miljkovic N.

A water droplet impacting onto a supercooled surface is typically considered to freeze and adhere to the substrate. This ice accretion poses safety and economic threats to transportation infrastructure, power generation/transmission systems, and telecommunication facilities. Here we report the observation of ultra-low ice-substrate adhesion (0–50 kPa) and remarkable self-deicing during droplet-impact freezing on copper surfaces having medium to high supercooling (30°C–80°C). Mechano-thermo-hydraulic coupling during droplet-impact freezing governs the ice-substrate adhesion by gapping the droplet-substrate contact, enabling self-peeling facilitated by thermal-mechanical stress relaxation. We observe a strong adhesion region in the center of the frozen droplet, which determines the adhesion strength, and develop a regime map to delineate the dependence of adhesion/peeling on droplet inertia, substrate supercooling, and surface wettability. Our work demonstrates key mechanisms governing ice-substrate adhesion during impact icing and presents an approach to passive self-deicing. • Clarification of the relationship among frost growth, peeling, cracking, and adhesion • Characterization of heterogeneous adhesion of droplet impact icing to substrates • Development of a regime map for self-peeling and ultra-low adhesion (0–50 kPa) • Demonstration of passive self-deicing for single and multiple impacting droplets A droplet impacting on a cold surface usually strongly sticks to the substrate during solidification. Jin et al. quantify the ultra-low ice-substrate adhesion and achieve spontaneous deicing on droplet impact freezing at high-surface supercoolings (>30°C).

Li L., Khodakarami S., Yan X., Fazle Rabbi K., Gunay A.A., Stillwell A., Miljkovic N.

The rapid anthropomorphic emission of greenhouse gases is contributing to global climate change, resulting in the increased frequency of extreme weather events, including unexpected snow, frost, and ice accretion in warmer regions that typically do not encounter these conditions. Adverse weather events create challenges for energy systems such as wind turbines and photovoltaics. To maintain energy efficiently and operational fidelity, snow, frost, and ice need to be removed efficiently and rapidly. State-of-the-art removal methods are energy-intensive (energy density > 30 J cm−2) and slow (>1 min). Here, pulsed Joule heating is developed on transparent self-cleaning interfaces, demonstrating interfacial desnowing, defrosting, and deicing with energy efficiency (energy density < 10 J cm−2) and rapidity (≈1 s) beyond what is currently available. The transparency and self-cleaning are tailored to remove both snow and dust while ensuring minimal interference with optical light absorption. It is experimentally demonstrated a multi-functional coating material on a commercial photovoltaic cell, demonstrating efficient energy generation recovery and rapid ice/snow removal with minimal energy consumption. Through the elimination of accretion, this technology can potentially widen the applicability of photovoltaics and wind technologies to globally promising locations, potentially further reducing greenhouse gas emissions and global climate change.

Zhang H., Xu X., Wu M., Zhao Y., Sun F., Xin Q., Zhou Y., Qin M., Zhou Y., Ding C., Li J.

Magnetic iron oxides, as the typical photothermal materials, possess the advantages of low cost, easy preparation, and biocompatibility, which impart great expectations in broad application prospects. However, the limited photothermal efficiency of iron oxides restricts their further use. Inspired by magnetotactic bacteria, a liquid film-confined strategy has been developed assisted by a magnetic field for mineralization and assembly of iron oxides on the surface at room temperature. Virus-like hierarchically micro/nanostructured iron oxides can be obtained on universal substrates which exhibit excellent photothermal performance, the highest among all iron oxide coatings and even comparable with carbon-based materials. Theoretical simulation demonstrates the promotion of light capture by these particular structures. Moreover, by virtue of this, the surface is endowed with superhydrophobicity by a simple modification to construct a photothermal superhydrophobic platform, which is demonstrated by two challenging scenarios: high-efficient antibacterial activity and defrosting/deicing ability controlled remotely. There is no need for harsh experimental conditions and templates, the strategy reported here is mild, environmental-friendly and adopts trace amount of liquid (55 µL cm−2), which can provide a reference for the fabrication and application of other photothermal materials.

Li Y., Ma W., Kwon Y.S., Li W., Yao S., Huang B.

In frigid winter, the ice and snow built-up on high-voltage overhead power lines may seriously risk the reliability of electric power transmission and telecommunication systems. Green technologies for power line deicing that can effectively remove the accumulated ice or snow on the cables in a gentle way are highly desired but technically challenging due to the complex cable surfaces. Herein, this work reports a scalable solar-thermal icephobic nanocoating compatible with both flat and complex curved surfaces. The spray-coated nanocoating comprises a titanium nitride nanoparticle layer as a low-emissivity photo-thermal medium and dual-scale silica particles as a water-repellent layer even at low temperatures. Enabled by the collective effects of high-efficiency solar-thermal conversion and temperature-insensitive superhydrophobicity, the nanocoating realizes effective deicing/defrosting on power lines at frigid temperatures down to −15 °C. The versatility of this coating and its compatibility with mass-production processes render passive solar-driven deicing technologies promising for practical applications on most outdoor exposed surfaces.

Ibáñez-Ibáñez P.F., Montes Ruiz-Cabello F.J., Cabrerizo-Vílchez M.A., Rodríguez-Valverde M.A.

Ice adhesion to rigid materials is reduced with low energy surfaces of high receding contact angles. However, their adhesion strength values are above the threshold value to be considered as icephobic materials. Surface deformability is a promising route to further reduce ice adhesion.In this work, we prepared elastomer surfaces with a wide range of elastic moduli and hydrophobicity degree and we measured their ice adhesion strength. Moreover, we also explored the deicing performance of oil-infused elastomeric surfaces. The ice adhesion was characterized by two detachment modes: tensile and shear.The variety of elastomeric surfaces allowed us to simultaneously analyze the ice adhesion dependence with deformability and contact angle hysteresis. We found that the impact of these properties depends on the detachment mode, being deformability more important in shear mode and hydrophobicity more relevant in tensile mode. In addition, oil infusion further reduces ice adhesion due to the interfacial slippage. From an optimal balance between deformability and hydrophobicity, we were able to identify surfaces with super-low ice adhesion.

Li N., Zhang Y., Zhi H., Tang J., Shao Y., Yang L., Sun T., Liu H., Xue G.

• The cactus-like Al micro/nanoparticles were formed on Al surface by LSDW treatment. • The Al nanoparticles exhibited strong plasmon effect and > 94.5% solar absorption. • FDTS chemically bonded with Al substrate and imparted CA of 161.2°. • The deicing surface endowed good thermal/cold stability and weak ice adhesion. • Multifunctional Al showed excellent photothermal anti-icing/deicing and defrosting ability. Photothermal anti-icing/deicing is an efficient way to circumvent the problems caused by the formation and accumulation of frost and ice to the people living in cold regions. However, achieving this process on robust materials with high efficiency and long-term stability is always challenging. Herein, we facilely constructed a black and superhydrophobic Al using Laser surface direct writing (LSDW) and thermal evaporation of 1H,1H,2H,2H-perfluorodecyltrichlorosilane for efficient anti-icing/deicing applications. The prepared multifunctional Al surface showed excellent superhydrophobicity with a contact angle of 161.2° and light-harvesting capacity with over 94.5% absorption (>96% in the visible spectral range) mainly based on the surface plasmonic resonance of cactus-like Al micro/nanoparticles. The multifunctional Al exhibited excellent light-induced heating and thermal/cold stability, reduced ice adhesion strength, and self-cleaning through its small sliding angle (approximately 0°). With good photothermal behaviors and superhydrophobicity, the multifunctional Al showed strong anti-icing capacity by inhibiting the nucleation and growth of ice crystals, and rapidly deicing and melting the frost and ice layers at − 30 °C. Fabricating such multifunctional Al provides a feasible method for high-efficient anti-icing/deicing applications relied on the green and renewable solar energy.

Budagosky J., García‐Casas X., Sánchez‐Valencia J.R., Barranco Á., Borrás A.

The growth of TiO2 and ZnO thin films is studied by means of coarse-grained kinetic Monte Carlo simulations under conditions typically encountered in plasma-enhanced chemical vapor deposition experiments. The basis of our approach is known to work well to simulate the growth of amorphous materials using cubic grids and is extended here to reproduce not only the morphological characteristics and scaling properties of amorphous TiO2 but also the growth of polycrystalline ZnO with a good approximation, including the evolution of the film texture during growth and its dependence on experimental conditions. The results of the simulations have been compared with available experimental data obtained by X-ray diffraction, analysis of the texture coefficients, atomic force microscopy, and scanning electron microscopy.

Zhao C., Geng W., Qiao X., Xue F., He J., Xue G., Liu Y., Wei H., Bi K., Li Y., Xun M., Chou X.

The ferroelectric materials own the natural anti-irradiation property, paving great potentials and applications regarding the aerospace fields. Benefiting from this property, LiNbO 3 -based surface acoustic wave (SAW) devices can be used for high accuracy sensing signal test under extreme circumstances. In this work, the 128° YX cut LiNbO 3 substrate was adopted for SAW resonator temperature sensor application, and the response frequency varied from 180.44 MHz to 177.628 MHz with temperature from 21.9 ℃ to 199.9 ℃. Subsequently, the device irradiated by 100 Krad Gamma ray was tested with vector network analyzer (VNA). A maximum frequency shift of ~ 0.38% was found under γ-ray irradiation with a dose of 100 Krad on account of slight irradiation effect. The results verify the radiation resistance ability of SAW for development of highly reliable temperature sensor in the irradiation environment. A novel SAW temperature sensor was analyzed, designed and fabricated with 128°YX LiNbO3 process platform, which can be used for testing temperature under irradiation experiment. • A SAW temperature sensor was fabricated by 128° YX cut LiNbO3 which could work under the irradiation experiment. • The sensor has good anti-irradiation property, that a maximum frequency shift of 0.38% was found under γ-ray irradiation. • The SAW temperature sensor was standardized and tested, and the device showed good stability.

García-Casas X., Ghaffarinejad A., Aparicio F.J., Castillo-Seoane J., López-Santos C., Espinós J.P., Cotrino J., Sánchez-Valencia J.R., Barranco Á., Borrás A.

We introduce herein the advanced application of low-pressure plasma procedures for the development of piezo and triboelectric mode I hybrid nanogenerators. Thus, plasma assisted deposition and functionalization methods are presented as key enabling technologies for the nanoscale design of ZnO polycrystalline shells, the formation of conducting metallic cores in core@shell nanowires, and for the solventless surface modification of polymeric coatings and matrixes. We show how the perfluorinated chains grafting of polydimethylsiloxane (PDMS) provides a reliable approach to increase the hydrophobicity and surface charges at the same time that keeping the PDMS mechanical properties. In this way, we produce efficient Ag/ZnO convoluted piezoelectric nanogenerators supported on flexible substrates and embedded in PDMS compatible with a contact–separation triboelectric architecture. Factors like crystalline texture, ZnO thickness, nanowires aspect ratio, and surface chemical modification of the PDMS are explored to optimize the power output of the nanogenerators aimed for harvesting from low-frequency vibrations. Just by manual triggering, the hybrid device can charge a capacitor to switch on an array of color LEDs. Outstandingly, this simple three-layer architecture allows for harvesting vibration energy in a wide bandwidth, thus, we show the performance characteristics for frequencies between 1 Hz and 50 Hz and demonstrate the successful activation of the system up to ca. 800 Hz. • Development of Mode I PTHNGs containing core@shell nanowires embedded in a perfluorinated PDMS triboelectric layer. • Conversiton from low to high frequencies in the low-frequency range, i.e. from 1 Hz to ca. 800 Hz. • Advantages of industrial-spread techniques: PECVD, sputtering, thermal evaporation, and oxygen plasma etching. • Room temperature, low power, and solventless plasma treatment of PDMS for efficient anchoring of perfluorinated molecules. • Demonstration of the perfluorinated grafting of the PDMS for enhanced power output, durable and reproducible devices.

Grishaev V.G., Borodulin I.S., Usachev I.A., Amirfazli A., Drachev V.P., Rudenko N.I., Gattarov R.K., Bakulin I.K., Makarov M.V., Akhatov I.S.

Some aircraft anti-icing fluids can dangerously weaken on hydrophobic surfaces. However, information about such fluids and surfaces was not full. Therefore, we considered the interaction of commercially available Newtonian and pseudo-plastic anti-icing fluids with super-hydrophilic and hydrophobic aluminum surfaces. In freezing rain simulations, no noticeable surface effect was observed on fluid endurance times at 10% ice coverage of the surfaces. The difference with previous works can be caused by fluid surface tensions, the contact angle hysteresis of test plates, and fluid viscosity (the last is irrelevant for Newtonian fluids). In further comparative studies, the roughness must also be considered because on rough hydrophobic surfaces the Newtonian fluid took longer to freeze once ice coverage surpassed 20% compared to smooth super-hydrophilic surfaces. Furthermore, the fluid physical adsorption in the surface texture leads to the drifting of receding contact angles of water on hydrophobic surfaces, thereby worsening their water-repelling. Thus, smooth hydrophobic surfaces are probably the preferred solution for ice mitigation systems contacting aircraft anti-icing fluids.

Yin Y., Cheng L., Wang W., Zhang Y., Liang Y.

We propose a new theoretical method and experimental investigation to characterize the growth process of rime ice through surface acoustic waves (SAWs). The Biot theory of dual-phase porous media was employed to construct a theoretical model to describe the acoustic wave propagation in porous rime ice; the transient changes in acoustic propagation attenuation and velocity were simulated; and the icing sensing mechanism of the acoustic wave propagation attenuation (∼18 dB) and the transient change in velocity (0.8 m/s) during the icing process was obtained. A 177.5 MHz waveguide type SAW micro–nano-device with an SU8/ST-90°X quartz multilayer composite film structure and a microfluidic cavity on the top of the acoustic device were designed and fabricated, and the transient attenuation in the growth of rime ice was evaluated experimentally. The experimental results indicated that the appearance of rime ice can be monitored accurately by utilizing the transient changes in acoustic wave velocity and attenuation. Therefore, the acoustic method can aid in the early warning of the development status of rime ice.

Zeng X., Yan Z., Lu Y., Fu Y., Lv X., Yuan W., He Y.

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.

Anisimkin V.I., Voronova N.V.

• Lamb waves with elliptic polarization oriented parallel to the plate faces exist in crystal plates. • Particular polarization is maintained at any depth from free faces, for wide range of plate thickness. • The new waves are promissing for sensing liquid viscosity and liquid-to-ice phase transitions. Using quartz plates as an example existance of the new modification of the Lamb waves is demonstrated. The waves have small vertical displacement, large shear-horizontal and longitudinal components, and elliptic polarization which is oriented parallel to the plate faces. Numerical calculations of the surface displacements and depth profiles show the particular polarization is maintained at any depth from free faces and for all plate thickness in the range h/λ = 0–1.7 (h - thickness, λ - wave length). Results of the measurements accomplished for four new modes and three plate thickness h/λ confirm that radiation of the waves into adjucent liquid (which is proportional to vertical displacement) is small, while viscoelestic loss of the same the waves (which is proportional to in-plane components) is large. This property makes the modified waves suitable for sensing liquids and ices. In particular, responses of the waves towards liquid viscosity and water-to-ice transformation are larger than those are for common Lamb waves approaching 27 and 50 dB, respectively, at about 30 MHz, 1500 cP, and 10 mm propagation path.

Li W., Zhan Y., Yu S.

Because undesired surface icing can cause tremendous losses to human life and property, innovative methods of anti-icing must be exploited urgently. Recent increasing studies suggest that superhydrophobic coatings originating from nature possess active anti-icing performances and great application prospects, but such anti-icing performances and developments in practical applications are restricted by various factors. In this review, the wide applications, general theories and mechanisms of anti-icing of superhydrophobic coatings were introduced. Subsequently, the main impact factors, including the internal factors such as the morphology of surface rough structure and mechanical strength of superhydrophobic coatings, and the external factors such as environmental atmosphere and/or weather conditions on anti-icing performances were discussed and analyzed. Furthermore, aiming at the factors currently difficult to eliminate, the functional superhydrophobic coatings with unique properties such as self-migration, easy-repairable, and self-healing as countermeasures were proposed, and their current research status was given a full overview, and especially the problems and challenges were indicated. Finally, conclusions, future trends, and development directions of such anti-icing superhydrophobic coatings were presented.

Zhuo Y., Xiao S., Amirfazli A., He J., Zhang Z.

• A first review on polysiloxane as icephobic materials. • Icephobic surfaces were categorized by their low-ice-adhesion mechanisms. • The advantages and shortcomings of each polysiloxane material group were assessed. • A reference coating thickness and a lower bound of ice adhesion were identified. • The challenges in applying the polysiloxane materials were discussed. 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.

zhu J., Li W., Wang T., Feng H., Cheng J., Lin C., Wang X., Wang W., Chen S.

Qin X., Cong Q., Xu J., Chen T., Jin J., Liu C., Wang M.

Do Park G., Soo Lee Y., Joon Lee S.

Ong H.L., Ji Z., Haworth L., Guo Y., del Moral J., Jacob S., Borras A., Gonzalez‐Elipe A.R., Zhang J., Zhou J., McHale G., Fu Y.

Fogging, icing, or frosting on optical lenses, optics/photonics, windshields, vehicle/airplane windows, and solar panel surfaces have often shown serious safety concerns with hazardous conditions and impaired sight. Various active techniques, such as resistive heating, and passive techniques, such as icephobic treatments, are widely employed for their prevention and elimination. However, these methods are not always suitable, effective, or efficient. This review provides a comprehensive overview of the fundamentals and recent advances of transparent thin‐film surface acoustic wave (SAW) technologies on glass substrates for monitoring and prevention/elimination of fogging, frosting, and icing. Key challenges related to fogging and icing on glass substrates are discussed, along with fundamental mechanisms that establish thin‐film SAWs as optimal solution for these issues. Various types of thin‐film acoustic wave technologies are discussed, including recent wearable and flexible SAW devices integrated onto glass substrates for expanding future applications. The focus of this review is on the principles and strategies for hybrid or integrated de‐fogging/de‐icing and sensing/monitoring functions. Finally, critical issues and future outlooks for thin‐film‐based SAW technology on glass substrates in industry applications are presented.

Pandey S., del Moral J., Jacob S., Montes L., Gil‐Rostra J., Frechilla A., Karimzadeh A., Rico V.J., Kantar R., Kandelin N., López‐Santos C., Koivuluoto H., Angurel L., Winkler A., Borrás A., et. al.

Acoustic waves (AW) have recently emerged as an energy‐efficient ice‐removal procedure compatible with functional and industrial‐relevant substrates. However, critical aspects at fundamental and experimental levels have yet to be disclosed to optimize their operational conditions. Identifying the processes and mechanisms by which different types of AWs induce de‐icing are some of these issues. Herein, using model LiNbO3 systems and two types of interdigitated transducers, the e‐icing and anti‐icing efficiencies and mechanisms driven by Rayleigh surface acoustic waves (R‐SAW) and Lamb waves with 120 and 510 μm wavelengths, respectively, are analyzed. Through the experimental analysis of de‐icing and active anti‐icing processes and the finite element simulation of the AW generation, propagation, and interaction with small ice aggregates, it is disclosed that Lamb waves are more favorable than R‐SAWs to induce de‐icing and/or prevent the freezing of small ice droplets. Prospects for applications of this study are supported by proof of concept experiments, including de‐icing in an icing wind tunnel, demonstrating that Lamb waves can efficiently remove ice layers covering large LN substrates. Results indicate that the de‐icing mechanism may differ for Lamb waves or R‐SAWs and that the wavelength must be considered as an important parameter for controlling the efficiency.

Zhao L., Shen Y., Tao J., Liu W., Wang T., Liu S.

AbstractIn response to the hazards of icing in the energy, transportation, and aerospace sectors, extensive research has been conducted on anti‐icing materials based on the solid‐liquid/ice interface theory, as well as reliable chemical and electro‐thermal de‐icing systems. However, there is an urgent need for modernizing anti‐icing systems to address diverse application scenarios. Gaining insights into the influence of interface action forces on water droplet behavior can proactively prevent detrimental icing occurrences. Nevertheless, under severe conditions where ice formation is inevitable, leveraging interface action forces to induce cracking and expansion of ice facilitates its rapid detachment despite potential challenges associated with complete removal. A comprehensive review elucidating the mechanisms through which interface action forces impact water/ice formations encompasses various approaches toward designing mechanically‐driven de‐icing systems.

Wang R., Ouyang D., Zhou D., Li Z., Deng Y., Xue M., Chen Y., Hong Z., Luo Y., Yin Z.

Xia G., Fang J., Shou D., Wang X.

Mao M., Wei J., Li B., Li L., Huang X., Zhang J.

Photothermal superhydrophobic coatings are supposed promising to prevent ice accumulation on infrastructures but often experience significant performance degradation in real icing conditions and lack mechanical robustness. Here, we report design of robust photothermal superhydrophobic coatings with three-tier hierarchical micro-/nano-/nanostructures by deposition of nanosized MOFs on natural attapulgite nanorods, fluorination, controlled phase separation of a hydrophobic adhesive and spraying assembly. Phase separation degree and adhesive content significantly influence the coatings’ properties by regulating the structural parameters and morphology. In simulated/real icing environments, the coatings simultaneously show (i) high superhydrophobicity and stable Cassie-Baxter states due to their low-surface-energy, three-tier micro-/nano-/nanostructure, (ii) excellent photothermal effect primarily due to nanosized MOFs, and (iii) good mechanical robustness by the phase-separated adhesive, reinforcement with attapulgite and the coatings’ self-similar structure. Accordingly, combined with low thermal conductivity, the coatings exhibit remarkable anti-icing/frosting (e.g., no freezing in at least 150 min and almost free of frost in 25 min) and de-icing/frosting performances (e.g., fast de-icing in 12.7 min and fast de-frosting in 16.7 min) in such environments. Furthermore, we realize large-scale preparation of the coatings at reasonable costs. The coatings have great application potential for anti-icing and de-icing in the real world by efficiently using natural sunlight. Photothermal superhydrophobic coatings show poor anti-icing performance and mechanical stability in real conditions. Here, authors report on robust photothermal superhydrophobic coatings with self-similar low-surface-energy three-tier micro-/nano- /nanostructures.

Gowda C.C., Kartsev A., Tiwari N., Safronov A.A., Pandey P., Roy A., Ajayan P.M., Galvao D.S., Tiwary C.S.

Two-dimensional (2D) chromium telluride, Cr2Te3 exhibits strong ferromagnetic ordering with high coercivity at low temperatures and paramagnetic behaviour when approaching room temperature. The spin states of monolayer Cr2Te3 shows ferromagnetic...

Reichel H., García-Valenzuela A., Andrés Espino-Román J., Gil-Rostra J., Fernando Regodón G., Rico-Gavira V., Borrás A., Gómez-Ramírez A., Palmero A., González-Elipe A.R., Oliva-Ramírez M.

Early results on the plasma deposition of dielectric thin films on acoustic wave (AW) activated substrates revealed a densification pattern arisen from the focusing of plasma ions and their impact on specific areas of the piezoelectric substrate. Herein, we extend this methodology to tailor the plasma deposition of metals onto AW-activated LiNbO3 piezoelectric substrates. Our investigation reveals the tracking of the initial stages of nanoparticle (NP) formation and growth during the submonolayer deposition of silver. We elucidate the specific role of AW activation in reducing particle size, enhancing particle circularity, and retarding NP agglomeration and account for the physical phenomena making these processes differ from those occurring on non-activated substrates. We provide a comparative analysis of the results obtained under two representative plasma conditions: diode DC sputtering and magnetron sputtering. In the latter case, the AW activation gives rise to a 2D pattern of domains with different amounts of silver and a distinct size and circularity for the silver NPs. This difference was attributed to the specific characteristics of the plasma sheath formed onto the substrate in each case. The possibilities of tuning the plasmon resonance absorption of silver NPs by AW activation of the sputtering deposition process are discussed.

Zhou X., Shen Y., Wang Z., Liu S., Fu X.

This chapter explores various active and passive anti-icing and de-icing technologies, focusing on their integration for enhanced efficiency. Active methods such as mechanical vibration, electrical pulse, and hot liquid/air techniques are detailed for their effectiveness in ice removal. Mechanical vibration uses high-frequency oscillations to weaken ice adhesion, while electrical pulse de-icing employs capacitors to generate magnetic fields that break the ice. Hot liquid/air de-icing utilizes high-temperature fluids or gases to melt ice. The chapter also discusses the coupling deicing behavior of these active methods with passive approaches, such as coatings with low solid-ice interface fracture toughness and superhydrophobic materials combined with piezoelectric and magnetic field technologies. This integrated strategy aims to improve energy efficiency and reliability, ensuring effective ice prevention and removal in various environmental conditions.

Gonzalez del Val M., Frövel M.

Icing has been an aeronautical industry problem for safety and for energy consumption save from the beginning of aviation. It affects the safety reducing the lift, decreasing the stall angle of attack, affecting the aircraft stability and reducing the control efficiency. The European project SENS4ICE (2019–2023) introduces a new technology based on hybridization of different detection techniques, combining indirect ice sensing with direct, using atmospheric and ice accretion sensors. In the present work a study about a Fiber Optic Detector based on latent heat that uses a Fiber Bragg Grating for measuring the surface temperature. The Fiber Optic Detector (FOD) was tested in a SAFIRE Flight Testing Platform ATR42 during 40 h of Flight testing, having Liquid Water encounters in all flights. The sensor performance and its ability for measuring the icing severity is evaluated in the paper, showing results in a representative Flight test. During Flight Test, different icing conditions were seen, adapting the detection and severity evaluations to the data seen with other reference atmospheric sensors. For ice detection Discrete Wavelet Transform (DWT) was used using different levels in order to detect all the possible events during the Flight test. The DWT ice severity assessment results were compared with a Messinger Model and with the DLR Nevzorov data in order to evaluate the precision and the sensor performance.

Xiong Y., Zhang Z., Liu Y., Ye M., Hu C., Chen J., Yan H., Huang Y.

Li X., Liu Y., Zhang Z., Liu Y., Leng J.

AbstractUnwanted ice formations may cause severe functional degradations of facilities and also have a negative impact on their lifespans. Avoiding and removing ice accumulation is always a hot topic in the industrial and technological field. Bionic functional surfaces have been greatly studied for several decades and have proved to be excellent candidates for passive anti‐/deicing applications. However, the drawbacks limit their potential industrial uses under harsh conditions, like low temperatures and high humidity. Most researches on bionic surfaces are focused on a certain function of natural creatures and their underlined fundamental theories are revealed by taking the interface as the static. Actually, living organisms, either plants or animals, are often sensitive and responsive to their surroundings, avoiding risks and even self‐repairing upon damage. From this prospect, a novel view of the bionic icephobic materials has been proposed in the present review, which is expected to be studied and designed by taking the biological species as a system. As two representative icephobic materials, the anti‐/deicing theories of superhydrophobic and slippery surfaces are first discussed. Further, the recent progress of smart icephobic strategies is summarized from interfaces to substrates. We aim to provide new bionic insights on designing future icephobic strategies.