All-Day Anti-Icing/Deicing Film Based on Combined Photo-Electro-Thermal Conversion

Mechanism and design strategy of ice-phobic surface: A comprehensive review

Ice accumulation on the surface can significantly impact the normal operation of industrial facilities and even lead to damage, resulting in economic losses. Modifying the physical structure and chemical state of the surface can effectively mitigate ice nucleation, growth, and adhesion processes. Building upon previous definitions of ice-phobic surfaces, this review provides a refined definition of ice-phobicity and reviews recent advancements in ice-phobic surfaces research. Firstly, ice-phobic mechanisms are summarized, which including principles of ice formation, theory of solid-liquid wettability of interface, and theory of solid-solid interface mechanics. Subsequently, strategies for developing near-term ice-phobic surfaces are discussed encompassing superhydrophobic surfaces, interfacial water induced surfaces, low adhesion surfaces, as well as thermal de-icing surfaces. Furthermore, a comparison is made regarding test detail definitions and commonly used test methods in researching ice-phobic surfaces to promote methodological uniformity. Lastly, the latest research findings on four distinct ice-phobic surfaces are highlighted, while also prospecting the challenges to be considered in future ice-phobic surface design.

A Critical Perspective on Photothermal De-Icing

To tackle the formidable challenges posed by extreme cold weather events, significant advancements have been made in developing functional surfaces capable of efficiently removing accreted ice. Nevertheless, many of these surfaces still require external energy input, such as electrical power, which raises concerns regarding their alignment with global sustainability goals. Over the past decade, increasing attention has been directed toward photothermal surface designs that harness solar energy-a resource available on Earth in quantities exceeding the total reserves of coal and oil combined. By converting solar energy into heat, these designs enable the transformation of the interfacial solid-solid contact (ice-substrate) into a liquid-solid contact (water-substrate), significantly reducing interfacial adhesion and facilitating rapid ice removal. This critical perspective begins by emphasizing the advantages of photothermal design over traditional de-icing methods. It then delves into an in-depth analysis of three primary photothermal mechanisms, examining how these principles have expanded the scope of de-icing technologies and contributed to advancements in photothermal surface design. Finally, key fundamental and technical challenges are identified, offering strategic guidelines for future research aimed at enabling practical, real-world applications.

A multi-layer flexible photothermal titanium nitride-based superhydrophobic surface for highly efficient anti-icing and de-icing

Ice accumulation presents a significant challenge for various residential activities and industrial facilities. Most current de-icing methods are time-consuming and costly. Photothermal superhydrophobic surfaces have garnered significant attention in the field of anti-icing and de-icing due to their environmentally friendly and energy-saving characteristics. However, obtaining photothermal superhydrophobic surfaces with both reliable icing delay and effective photothermal de-icing capabilities at ultra-low temperatures (<-30 °C) remains significantly challenging. In this study, we prepared a multilayer flexible photothermal TiN-based superhydrophobic surface (ML-SHS), comprising an FAS@SiO2/TiN superhydrophobic layer and a PDMS/Triton X-100 flexible supporting layer. The optimal ML-SHS exhibits excellent superhydrophobicity (a water contact angle of 162.7° and a sliding angle of 2°) and an average light absorption of 95.6%, and generates a substantial surface temperature increase of 80.2 °C under 1 sun illumination. Droplets easily roll off the ML-SHS at -10 °C without solar illumination and at -35 °C under 1 sun illumination, demonstrating excellent passive anti-icing capability. Due to its excellent photothermal conversion and thermal constraint capabilities, the accumulated ice layer on the ML-SHS rapidly melts within 450 seconds at -20 °C under 1 sun illumination. The ML-SHS also possesses self-cleaning properties, mechanical durability, and chemical stability, ensuring the usability of the superhydrophobic surface under harsh conditions. Our study may offer a novel approach for the design and fabrication of photothermal superhydrophobic surfaces, facilitating efficient passive anti-icing and active de-icing in practical applications.

Photothermal Conversion Porous Organic Polymers: Design, Synthesis, and Applications

Solar energy is a primary form of renewable energy, and photothermal conversion is a direct conversion process with tunable conversion efficiency. Among various kinds of photothermal conversion materials, porous organic polymers (POP) are widely investigated owing to their controllable molecular design, tailored porous structures, good absorption of solar light, and low thermal conductivity. A variety of POP, such as conjugated microporous polymers (CMP), covalent organic frameworks (COF), hyper-crosslinked porous polymers (HCP), polymers of intrinsic microporosity (PIM), porous ionic polymers (PIP), are developed and applied in photothermal conversion applications of seawater desalination, latent energy storage, and biomedical fields. In this review, a comprehensive overview of the recent advances in POP for photothermal conversion is provided. The micro molecular structure characteristics and macro morphology of POP are designed for applications such as seawater desalination, latent heat energy storage, phototherapy and photodynamic therapy, and drug delivery. Besides, a probe into the underlying mechanism of structural design for constructing POP with excellent photothermal conversion performance is methodicalized. Finally, the remaining challenges and prospective opportunities for the future development of POP for solar energy-driven photothermal conversion applications are elucidated.

Robust All-Day Frostphobic Surfaces

The application of solar-thermal surfaces for antifrosting and defrosting has emerged as a passive and environmentally friendly approach to mitigate the negative consequences of frost formation, such as structural damage and reduced heat transfer efficiency. However, achieving robust all-day frostphobicity solely through interfacial modification and solar-thermal effects is challenging in practical applications: The thick frost that accumulates at night strongly scatters solar radiation, rendering the solar-thermal coatings ineffective during the daytime. Additionally, these nanostructured coatings are susceptible to wear and tear when exposed to the outdoors for extended periods of time. To address these challenges, we present an innovative frostphobic surface that incorporates V-grooved structures with superhydrophobic solar-thermal layers (VSSs). The out-of-plane gradient structures facilitate spatially regulated vapor diffusion, an enhanced photothermal effect, and robust water repellency. These features not only prevent frost from covering the entire surface overnight, enabling effective solar-thermal defrosting during the daytime, but also protect the surface from deterioration. The combined merits ensure robust all-day frostphobicity and exceptional durability, making the VSS surface promising for practical applications and extending the lifespan in extreme environments.

A Flexible and High-Efficient Anti-Icing/Deicing Coating Based on Carbon Nanomaterials

Anti-icing/deicing coatings with low energy consumption and superior flexibility could better fit application requirements in practical engineering. In this paper, an active-passive-integrated anti-icing/deicing coating based on carbon nanomaterials is prepared, which not only possesses various functions of electrothermal conversion, photothermal conversion, and superhydrophobicity but also shows a large deformability to accommodate curved surfaces. The coating consists of a sandwich-structured bottom part and top layer, the former of which includes a core conductive layer made of densely mixed carbon nanotubes (CNTs) and graphene and two polydimethylsiloxane (PDMS) wrapping layers, while the latter is a polymeric composite filled with TiN and SiO2 nanoparticles. Experimental studies show that, when the present coating works under an electric field alone, a 90% conversion of electric energy to thermal energy can be realized, only a 2 V voltage is enough to unfreeze the surface at minus 20 degrees within 400 s, and a slightly larger voltage of 2.5 V leads to a significant temperature increase of more than 100 °C within 200 s. Such required voltages are significantly smaller than their counterparts in existing electrothermal-based methods to achieve the same heating effects, which could be further diminished with the auxiliary action of sunlight illumination. A fast and complete deicing/defrosting can be consequently achieved with a small energy input. Furthermore, the water repellency function, electric property, and electrothermal conversion performance of the coating remain almost unchanged after either a large bending deformation or many bending cycles, thus ensuring an outstanding anti-icing/deicing effect on both flat and curved surfaces. All of the results demonstrate apparent advantages of the present coating including high efficiency, low energy consumption, all-weather adaptability, and excellent flexibility, which should be of great practical value for the freeze protection of differently shaped industrial equipment.

Dynamical Janus-Like Behavior Excited by Passive Cold-Heat Modulation in the Earth-Sun/Universe System: Opportunities and Challenges

The utilization of solar-thermal energy and universal cold energy has led to many innovative designs that achieve effective temperature regulation in different application scenarios. Numerous studies on passive solar heating and radiation cooling often operate independently (or actively control the conversion) and lack a cohesive framework for deep connections. This work provides a concise overview of the recent breakthroughs in solar heating and radiation cooling by employing a mechanism material in the application model. Furthermore, the utilization of dynamic Janus-like behavior serves as a novel nexus to elucidate the relationship between solar heating and radiation cooling, allowing for the analysis of dynamic conversion strategies across various applications. Additionally, special discussions are provided to address specific requirements in diverse applications, such as optimizing light transmission for clothing or window glass. Finally, the challenges and opportunities associated with the development of solar heating and radiation cooling applications are underscored, which hold immense potential for substantial carbon emission reduction and environmental preservation. This work aims to ignite interest and lay a solid foundation for researchers to conduct in-depth studies on effective and self-adaptive regulation of cooling and heating.

A New Composite Material with Energy Storage, Electro/Photo-Thermal and Robust Super-Hydrophobic Properties for High-Efficiency Anti-Icing/De-Icing

All weather, high-efficiency, energy-saving anti-icing/de-icing materials are of great importance for solving the problem of ice accumulation on outdoor equipment surfaces. In this study, a composite material with energy storage, active electro-/photo-thermal de-icing and passive super-hydrophobic anti-icing properties is proposed. Fluorinated epoxy resin and MWCNTs/PTFE particles are used to prepare the top multifunctional anti-icing/de-icing layer, which exhibited super-hydrophobicity with water contact angle greater than 155° and conductivity higher than 69 S m-1. The super-hydrophobic durability of the top layer is verified through tape peeling and sandpaper abrasion tests. The surface can be heated by applying on voltage or light illumination, showing efficient electro-/photo-thermal and all-day anti-icing/de-icing performance. The oleogel material at the bottom layer is capable to absorb energy during heating process and release it during cooling process by phase transition, which greatly delayed the freezing time and saved energy. The icing test of single ice droplet, electro-/photo-thermal de-icing and defrosting tests also proved the high efficiency and energy saving of the anti-icing/de-icing strategy. This study provided a new way to manufacture multi-functional materials for practical anti-icing/de-icing applications.

Multi-Functional and Flexible Nano-Silver@MXene Heterostructure-Decorated Graphite Felt for Wearable Thermal Therapy

Wearable heaters with multifunctional performances are urgently required for the future personal health management. However, it is still challengeable to fabricate multifunctional wearable heaters simultaneously with flexibility, air-permeability, Joule heating performance, electromagnetic shielding property, and anti-bacterial ability. Herein, silver nanoparticles (AgNPs)@MXene heterostructure-decorated graphite felts are fabricated by introducing MXene nanosheets onto the graphite felts via a simple dip-coating method and followed by a facile in situ growth approach to grow AgNPs on MXene layers. The obtained AgNPs@MXene heterostructure decorated graphite felts not only maintain the intrinsic flexibility, air-permeability and comfort characteristics of the matrixes, but also present excellent Joule heating performance including wide temperature range (30-128 °C), safe operating conditions (0.9-2.7 V), and rapid thermal response (reaching 128 °C within 100 s at 2.7 V). Besides, the multifunctional graphite felts exhibit excellent electromagnetic shielding effectiveness (53 dB) and outstanding anti-bacterial performances (>95% anti-bacterial rate toward Bacillus subtilis, Escherichia coli and Staphy-lococcus aureus). This work sheds light on a novel avenue to fabricate multifunctional wearable heaters for personal healthcare and personal thermal management.

A Transparent Photo/Electrothermal Composite Coating with Liquid-like Slippery Property for All-Day Anti-/De-Icing

A photo/electrothermal surface can convert sunlight and electricity into heat to solve icing problems. The combination of active photo/electrothermal surfaces with passive slippery surfaces provides a highly efficient strategy for all-day anti/deicing. However, the lack of transparency remains a primary impediment to the widespread application of these anti-icing measures in photovoltaics, windshields, and other fields. Herein, we report a bilayer transparent photo/electrothermal coating with a liquid-like slippery property for all-day anti/deicing. The prepared coating exhibits ultraslippery, low ice adhesion, and enhanced stability properties through covalent grafting of polydimethylsiloxane (PDMS) brushes in a cross-linked skeleton of epoxy. Moreover, the coating demonstrates a visible transmittance of up to 77% and effectively absorbs ultraviolet and near-infrared light due to the addition of ultraviolet and infrared absorbers, resulting in a temperature increase under sun illumination. The bottom indium tin oxide layer is fabricated to provide the composite coating with electrothermal capability, so that it can achieve all-weather deicing. The coupling of photo/electrothermal and slippery properties can promote the rapid removal of grown ice in a short time. The slippery properties and their exceptional durability under mechanical, optical, and thermal conditions render the composite coatings highly promising for engineering applications.

Photothermal, Magnetic, and Superhydrophobic PU Sponge Decorated with a Fe3O4/MXene/Lignin Composite for Efficient Oil/Water Separation

Frequent oil spills and the discharge of industrial oily wastewaters have become a serious threat to the environment, ecosystem, and human beings. Herein, a photothermal, magnetic, and superhydrophobic PU sponge decorated with a Fe3O4/MXene/lignin composite (labeled as S-Fe3O4/MXene/lignin@PU sponge) has been designed and prepared. The obtained superhydrophobic/superoleophilic PU sponge possesses excellent chemical stability, thermal stability, and mechanical durability in terms of being immersed in corrosive solutions and organic solvents and boiling water and being abrased by sandpapers, respectively. The oil adsorption capacities of the S-Fe3O4/MXene/lignin@PU sponge for various organic liquids range from 29.1 to 70.3 g/g, and the oil adsorption capacity for CCl4 can remain 69.6 g/g even after 15 cyclic adsorption tests. The separation efficiencies of the S-Fe3O4/MXene/lignin@PU sponge for n-hexane and CCl4 are higher than 98% in different environments (i.e., water, hot water, 1 mol/L NaOH, 1 mol/L NaCl, and 1 mol/L HCl). More importantly, the introduction of three light absorbers (i.e., Fe3O4, MXene, and lignin) into the S-Fe3O4/MXene/lignin@PU sponge shows a synergistic effect in the photothermal heat conversion performance, and the maximum surface temperature reaches 64.4 °C under sunlight irradiation (1.0 kW/m2). The separation flux of the S-Fe3O4/MXene/lignin@PU sponge for viscous LT147 vacuum pump oil reaches 35,469 L m-2 h-1 under sunlight irradiation, showing an increase of 27.3% compared to that of oil adsorption processes without the photothermal effect. Thus, the rational design of superhydrophobic sponges by introducing proper photothermal heat absorbers provides new insights into facile and cost-effective preparation of sponges for efficient oil/water separation.

A Highly Transparent Photo-Electro-Thermal Film with Broadband Selectivity for All-Day Anti-/De-Icing

A photo- and electro-thermal film can convert sunlight and electricity into heat to solve icing problems. Combination of them provides an efficient strategy for all-day anti-/de-icing. However, only opaque surfaces have been reported, due to the mutual exclusiveness between photon absorption and transmission. Herein, a highly transparent and scalable solution-processed photo-electro-thermal film is reported, which exhibits an ultra-broadband selective spectrum to separate the visible light from sunlight and a countertrend suppress of emission in longer wavelength. It absorbs ≈ 85% of invisible sunlight (ultraviolet and near-infrared) for light-heat conversion, meanwhile maintains luminous transmittance > 70%. The reflection of mid-infrared leads to low emissivity (0.41), which further preserves heat on the surface for anti-/de-icing purpose. This ultra-broadband selectivity enables temperature elevation > 40 °C under 1-sun illumination and the mutual support between photo-thermal and electro-thermal effects contributes to > 50% saving of electrical consumption under weak solar exposure (0.4-sun) for maintaining unfrozen surfaces at -35 °C environment. The reverberation from photo-electro-thermal and super-hydrophobic effects illustrates a lubricating removal of grown ice in short time (< 120 s). The self-cleaning ability and the durability under mechanical, electrical, optical, and thermal stresses render the film stable for long-term usage in all-day anti-/de-icing applications.

High-Efficient Anti-Icing/Deicing Method Based on Graphene Foams

Anti-icing/deicing has always been a focal issue in modern industries. A novel anti-icing/deicing material based on graphene foams (GF) is prepared in this paper, which integrates multiple functions, including electrothermal conversion, photothermal conversion, and superhydrophobicity. The GF sheet is used as a bottom layer bonded on the protected substrate, which is covered by a polymeric composite coating filled with TiN and SiO2 nanoparticles. Electric heating and light heating experiments are performed to study the anti-icing/deicing performances of such a GF-based material. It is found that, under the unique action of electric fields, a voltage of only 1 V is needed to increase the surface temperature from minus tens of degrees to the one above zero within 400 s, which is much lower than their previous counterparts of more than 10 V to achieve the same unfreezing effect. A slight increase of the applied voltage to 1.5 V can even result in a remarkable increase of the surface temperature from room temperature to more than 150 °C within 200 s, in contrast to existing electric heating techniques to attain peak temperatures of about 100 °C at the expense of tens of volts. Such performances enable the GF-based material to achieve an outstanding electrothermal energy conversion rate of more than 90%. Furthermore, with the help of sunlight illumination in addition to the electric power, not only can the critical voltage to prevent icing be reduced but also a much more rapid and adequate removal of ice or frost from the surface can be realized compared with the deicing/defrosting performance under either electric or light field alone. All of these results demonstrate the obvious advantages of the present method in superior energy utilization efficiency and universal applicability to dark and sunlight environments, which should be particularly useful for at-all-cost protection of key components in industrial equipment from icing.

Photo-Thermal Superhydrophobic Sponge for Highly Efficient Anti-Icing and De-Icing

Ice accretion always brings much inconvenience in the field of production and life. How to anti-ice or de-ice easily on solid surfaces becomes research focus in the engineering material fields. In this work, a kind of photo-thermal superhydrophobic polyurethane sponge (PSP-SPONGE) was developed by depositing Fe₃O₄ nanoparticles and polydopamine and simple fluorination treatment to realize anti-icing and de-icing fast under faint sunlight irradiation. Utilizing the thermal insulation of porous PSP-SPONGE, the photo-thermal energy was located at the sunlight irradiation area, which heated PSP-SPONGE surface rapidly under sunlight irradiation in cold surroundings. Water droplets on PSP-SPONGE surface would never freeze under faint 0.3 kW/m² ("0.3 sun") sunlight illumination in -30 °C damp surroundings, and the ice melts entirely within 18 min under "1 sun" illumination. Furthermore, PSP-SPONGE has excellent self-cleaning and self-healing properties that can cope with the complex and volatile natural environment to guarantee durable anti-icing and de-icing performances. The simulated outdoor snow removal test also proved that snow on PSP-SPONGE surface could melt under "0.5 sun" sunlight illumination in -30 °C damp surroundings. The PSP-SPONGE fabricated with simple preparation and easy access has wide application prospects in anti-icing and de-icing.

Heat Transfer Characteristics of Carbon-Based Photothermal Superhydrophobic Materials with Thermal Insulation Micropores During Anti-icing/Deicing

Photothermal deicing is a noncontact, economically, efficient, and environmentally friendly melting/preventing ice method. Obtaining a cheap, easily fabricated material with high photothermal conversion and deicing efficiency is a challenge. Here, carbon-based photothermal superhydrophobic materials with thermal insulation micropores were prepared by using the salt-template. We demonstrate that the microholes array structure can enhance light absorption and hydrophobicity of the material, and the micropores structure can inhibit the heat transfer from the surface to the subcooled substrate, which synergistically greatly enhances the photothermal conversion. A heat transfer model was established to clarify the influence mechanisms of air cushion on interfacial heat transfer during the photothermal anti-icing and deicing process. The self-cleaning, flexibility, mechanical, and chemical stability tests show that the material has the potential for outdoor application. The prepared materials with high photothermal deicing efficiency provide a new way for the anti-icing and deicing of outdoor equipment.

Recent advances of bio-inspired anti-icing surfaces

The need for improved anti-icing surfaces is the demand of the time and closely related to many important aspects of our lives as surface icing threatens not only industrial production but also human safety. Freezing on a cold surface is usually a heterogeneous nucleation process induced by the substrate. Creating an anti-icing surface is mainly achieved by changing surface morphology and chemistry to regulate the interaction between the surface and the water/ice to inhibit freezing on the surface. In this paper, recent research progress in the creation of biomimetic anti-icing surfaces is reviewed. Firstly, basic strategies of bionic anti-icing are introduced, and then bionic anti-icing surface strategies are reviewed according to four aspects: the process of ice formation, including condensate self-removing, inhibiting ice nucleation, reducing ice adhesion, and melting accumulated ice on the surface. The remaining challenges and the direction of future development of biomimetic anti-icing surfaces are also discussed.

Bio-Inspired Hollow Carbon Microtubes for Multifunctional Photothermal Protective Coatings

Solar energy-facilitated materials are promising to solve energy problems by converting clean solar energy to thermal energy. However, heat loss of photothermal materials still limits the photothermal conversion phenomenon. Herein, we designed bio-inspired hollow carbon microtubes (HCMTs) by one-step carbonization of renewable cotton fibers, which can avoid the complex preparation procedures of the template method. Similar to polar bears, the hollow construction can efficiently reduce heat loss, which improves the utilization of light and photothermal property. The HCMTs can be applied on a variety of substrates to obtain multifunctional photothermal protective coatings. The temperature of the coating can rapidly warm up to 97.7 °C under 1 kW/m² sun irradiation. In addition, the coatings show excellent superhydrophobic property (CA of 161.5 ± 0.9°), which can prevent the adhesion of the contaminant and maintain the long-time photothermal property of the surface. Also, the coating is able to withstand sandpaper abrasion, repeat tape-peeling, and tribological friction without losing superhydrophobic properties, indicating remarkable mechanical stability. Furthermore, the coating can withstand high-temperature calcination (400 °C), long-time UV radiation, and corrosive liquid erosion, which exhibits prominent chemical stability. More importantly, the combination of active deicing and passive anti-icing of the coating can effectively prevent the formation and accumulation of ice on the surface. The outstanding environmental adaptability can greatly extend its lifespan and meet the long-term service conditions.

Micro-Nano-Nanowire Triple Structure-Held PDMS Superhydrophobic Surfaces for Robust Ultra-Long-Term Icephobic Performance

Anti-icing superhydrophobic surfaces have attracted tremendous interests due to their repellency to water and extremely low ice affinity, whereas the weak durability has been the bottleneck for further applications. Surface durability is especially important in long-term exposure to low-temperature and high-humidity environments. In this study, a robust micro-nano-nanowire triple structure-held PDMS superhydrophobic surface was fabricated via a hybrid process: ultrafast-laser-prepared periodic copper microstructures were chemically oxidized, followed by modification of PDMS. The hedgehog-like surface structure was composed of microcones, densely grown nanowires, and tightly combined PDMS. The capillary force difference in micro-nanostructures drove PDMS solutions to distribute evenly, bonding fragile nanowires to form stronger composite cones. PDMS replaced the commonly used fragile fluorosilanes and protected nanowires from breaking, which endowed the surfaces with higher robustness. The ductile PDMS-nanowire composites possessed higher resiliency than brittle nanowires under a load of 1 mN. The surface kept superhydrophobic and ice-resistant after 15 linear abrasion cycles under 1.2 kPa or 60 icing-deicing cycles under -20 °C or 500 tape peeling cycles. Under a higher pressure of 6.2 kPa, the contact angle (CA) was maintained above 150° until the abrasion distance exceeded 8 m. In addition, the surface exhibited a rare spontaneously optimized performance in the icing-deicing cycles. The ice adhesion strength of the surface reached its lowest value of 12.2 kPa in the 16th cycle. Evolution of surface roughness and morphology were combined to explain its unique U-shaped performance curves, which distinguished its unique degradation process from common surfaces. Thus, this triple-scale superhydrophobic surface showed a long-term anti-icing performance with high deicing robustness and low ice adhesion strength. The proposed nanostructure-facilitated uniform distribution strategy of PDMS is promising in future design of durable superhydrophobic anti-icing surfaces.

Facilely Fabricated Self-Lubricated Photothermal Coating with Long-Term Durability and External-Replenishing Property for Anti-Icing/Deicing

Icing has a severe negative impact on daily life and equipment stability. The slippery liquid-infused porous surface (SLIPS) has been widely studied for icephobicity. However, loss of lubrication leads to the failure of icephobicity. In this work, a self-lubricating photothermal surface (SLPS) based on multiwalled carbon nanotubes (MWNTs) and silicone oil was fabricated by a facile preparation method to realize passive anti-icing/deicing and active deicing simultaneously. SLPS can inhibit frost formation, delay freezing, and reduce ice adhesion strength (τ_ice) under low-light and dark conditions. The τ_ice value of SLPS-5-2 was 5.82 kPa in the absence of light at -20 °C. MWNTs improve the oil locking ability and inhibit oil loss, enhancing durability. The τ_ice value of SLPS-5-2 remained within 20 kPa during 30 icing cycles. Meanwhile, SLPS has the excellent external replenishment capability to recover icephobicity. In addition, SLPS shows excellent photothermal deicing performance to melt frost, droplets, and ice layer quickly. Icing can be removed fast due to the oil layer. Silicone oil enhances the lateral heat transfer, improving the photothermal deicing. This all-in-one integration of the self-lubricating and photothermal effect finally boosts icephobicity compared to the traditional SLIPS or individual photothermal materials toward environmentally compatible and solar-driven icephobicity.

Ice-Shedding Polymer Coatings with High Hardness but Low Ice Adhesion

Ice readily sheds from weak oil-swollen polymer gels but tends to adhere to mechanically robust coatings. This paper reports bilayer coatings that simultaneously possess high bulk hardness but low ice adhesion. These coatings are prepared by cocuring a triisocyanate, P#'-g-PDMS [a methacrylate polyol bearing poly(dimethylsiloxane) (PDMS) side chains with # being 1, 2, or 3 and g denoting graft], and optionally a methacrylate polyol P#. The self-assembly of the system during coating formation yields a PDMS brush layer on the surface of the cross-linked polyurethane matrix. After the surface PDMS layer is lubricated with a silicone oil, this coating exhibits an ice adhesion τ that is 10 000-fold lower than that of a triisocyanate/P# coating. Ice slides under its own weight on such a coating at a tilt angle of 3°. Yet, the coating matrix is harder than poly(ethylene terephthalate), a widely used plastic. Additionally, such a coating maintains its low τ values for more than 10 consecutive icing/deicing cycles. Subsequent increases in τ are reversed by allowing time for the replenishment of the depleted surface lubricant with that released from the coating matrix. This design opens the door for effective yet hard ice-shedding polymer coatings.

Design of Icephobic Surfaces by Lowering Ice Adhesion Strength: A Mini Review

Ice accretion can lead to severe consequences in daily life and sometimes catastrophic events. To mitigate the hazard of icing, passive icephobic surfaces have drawn widespread attentions because of their abilities in repelling incoming water droplets, suppressing ice nucleation and/or lowering ice adhesion strength. As time elapses and temperature lowers sufficiently, ice accretion becomes inevitable, and a realistic roadmap to surface icephobicity for various outdoor anti-icing applications is to live with ice but with the lowest ice adhesion strength. In this review, surfaces with icephobicity are critically categorized into smooth surfaces, textured surfaces, slippery surfaces and sub-surface textured surfaces, and discussed in terms of theoretical limit, current status and perspectives. Particular attention is paid to multiple passive anti-icing strategies combined approaches as proposed on the basis of icephobic surfaces. Correlating the current strategies with one another will promote understanding of the key parameters in lowering ice adhesion strength. Finally, we provide remarks on the rational design of state-of-the-art icephobic surfaces with low ice adhesion strength.