Versatile Melanin-Like Coatings with Hierarchical Structure toward Personal Thermal Management, Anti-Icing/Deicing, and UV Protection

Recent Advances of Sustainable UV Shielding Materials: Mechanisms and Applications

The escalating global threat of ultraviolet (UV) radiation is manifested through multifaceted damage pathways including cutaneous carcinogenesis, photodegradation of organic substrates, marine ecosystem destabilization, and infrastructure weathering. These urgent challenges have catalyzed sustained interdisciplinary efforts toward advanced UV-shielding technologies spanning biomedical, environmental, and industrial domains. Current material arsenals include melanin, lignin, tannin, polydopamine, zinc oxide and titanium dioxide, etc. These materials can be applied to diverse fields such as food packaging, sunscreen fabrics, sunscreen creams, eyeglasses, and sunscreen films through tailored processing techniques and employing distinct photoprotective mechanisms. Notwithstanding significant progress, the development of an integrated selection framework that reconciles efficiency, durability, and environmental compatibility persists as a critical knowledge gap. In this context, the main mechanisms of various types of UV shielding materials and their applications in different fields are described systematically. Subsequently, a comparative analysis of the advantages and shortcomings of different materials is presented, focusing on their UV shielding efficiency and stability impact. Moreover, the review delves into their unique value in specific scenarios. Finally, building on these analyses, current challenges and future development prospects of UV shielding materials are further discussed, with emphasis on scalability, eco-friendly alternatives, and multifunctional integration, providing valuable insights and guidance for advancing research and promoting sustainable and functional innovations in this field.

Triple Biomimetic Surfaces with Patterned Anisotropic Wettability for Multiscale Droplets Manipulation

Droplets manipulation has attracted increasing attention for its increasingly widespread applications. However, current droplet manipulation usually needs complex preparation methods. Here, inspired by lotus leaves, rive leaves, and desert beetles, triple biomimetic surfaces are prepared through laser and heating. The mastoid structures contribute to the construction of superwettability. Within effective cycles, patterned scanning laser processing helps to achieve various interlaced wettability. The groove structure compensates for the decrease in droplet manipulation ability caused by the attenuation of superwettability. Meanwhile, the groove structure endows the scanning regions with good durability. The groove structure and interlaced wettability together constitute the anisotropic suface patterns. Macroscopic and microscopic droplet manipulation has been successfully achieved, demonstrating widespread applications. This work not only provides a titanium surface with triple biomimetic properties but also provides new insights for various droplet manipulations on metal surfaces.

A Photoelectric Synergistic Flexible Solid Slippery Surface for All-Day Anti-Icing/Frosting

The accumulation of ice on surface has caused great harm to lots of fields such as transportation or aerospace. Nowadays, various equipment or tools used in low-temperature environments, which face the risk of interface icing, usually have irregular shapes. Traditional rigid anti-icing materials are difficult to meet practical application requirements. Thus, it is crucial to develop flexible anti-icing materials that can be applied to various shape surfaces (curved surfaces, flat surfaces). In this paper, a photoelectric synergistic flexible solid slippery surface (FSSS) is prepared by using flexible basalt fiberglass cloth, flexible copper foil, flexible polyurethane/carbon nanotubes mixture, and flexible solid lubricant (the mixture of coconut wax and coconut oil). Even under harsh conditions of the temperature as low as -80 °C, the FSSS exhibits excellent all-day anti/de-icing performance whether on flat or curved surface. Moreover, the FSSS shows long-term stability both on flat and curved surface: situated in air for 60 days, submerged in water for 60 days, kept in acid environment (pH 1) and base environment (pH 13) for 30 days. Besides, the FSSS can also achieve self-healing function under -80 °C. This flexible surface provides a novel approach for de-icing/frosting of multi-shaped objects in the future.

Ex Situ pH-Induced Reversible Wettability Switching for an Environmentally Robust and High-Efficiency Stain-Proof Coating

Developing superwetting coatings with environmental adaptability is critical for sustainable industrial applications. However, traditional anti-wetting coatings often fall short due to their susceptibility to environmental factors (UV light, temperature, mold growth, and abrasion) and inadequate stain resistance in complex media. Herein, a durable ex situ pH-responsive coating with reversible wettability switching, engineered by integrating hydrophobic polydimethylsiloxane and tertiary amine structures is presented. The resulting hierarchical micro-nano surface structure, combined with a trapped air cushion, ensures low water adhesion and stable superhydrophobicity. Notably, after ex situ pH treatment, the modulation of surface N+ content synergistically interacts with polydimethylsiloxane chains, enabling a controlled transition in surface wettability from 150° to 68.5°, which can spontaneously revert to a hydrophobic state upon heating and drying. This transition enhances stain resistance in both air and underwater environments, resulting in a 17.2% increase in detergency compared to superhydrophobic controls. Moreover, the coating demonstrates remarkable durability, with no staining, peeling, or mildew growth (grade 0) even after 1500 h of UV radiation and 28 days of mildew resistance testing. This work offers a highly adaptable and stain-resistant coating for applications in building and infrastructure protection, as well as in smart textiles designed for multi-media decontamination.

Durable Photothermal Superhydrophobic Coating Comprising Micro- and Nanoscale Morphologies and Water-Soluble Siloxane for Efficient Anti-Icing and Deicing

Photothermal superhydrophobic coatings offer immense promise for anti-icing and deicing applications. However, achieving long-term passive anti-icing and active deicing in photothermal superhydrophobic coating remains a significant challenge. We introduce a durable photothermal superhydrophobic coating, coprepared from water-soluble polytrimethylsiloxane (PMATF) in synergy with cactus-inspired composite nanoparticles (MPCS), which is composed of MoS2, polydopamine (PDA), Cu nanoparticles, and octadecanethiol (18-SH). The PM-MPCS coating exhibits a maximum water contact angle (WCA) of 171.8° and retains a high WCA after 330 cycles of sandpaper abrasion and 210 cycles of tape peeling. Additionally, the PM-MPCS coating exhibits exceptional photothermal conversion ability. The PM-MPCS films attain a surface temperature of 86.9 °C, displaying a photothermal conversion efficiency of 77.4%. In anti-icing tests conducted at -15 °C, PM-MPCS significantly prolonged the freezing time; the freezing time of a 5 μL water droplet was extended to 43 min. The active deicing performance is similarly effective, with PM-MPCS melting a 5 μL ice sphere in 5.5 min. Furthermore, PM-MPCS exhibits a low ice adhesion strength of 6.0 kPa, enabling effective ice removal even after numerous freeze-thaw cycles. The exceptional anti-icing and deicing performance can be attributed to the synergistic effects of the composite nanoparticles, which minimize ice penetration and enhance the photothermal conversion capabilities of the particles. These findings underscore the potential of PM-MPCS as a viable candidate for advanced anti-icing and deicing applications across various industries.

Flexible, breathable, and durable superhydrophobic cotton fabric modified by behenic acid, tung oil, and ZIF-8 with anti-icing and self-cleaning properties

Textiles with self-cleaning and anti-icing capabilities in cold climates are essential for outdoor workers and enthusiasts. Superhydrophobic modification of textile surfaces is effective in imparting these characteristics. Although there are numerous methods available for manufacturing superhydrophobic textiles, careful consideration is warranted for environmental concerns over fluorochemicals, stability of superhydrophobic coatings, and fabric breathability. In this work, we utilized biomass resources such as tung oil and behenic acid, along with zeolitic imidazolate framework (ZIF-8), to modify cotton fabrics, thereby creating an innovative behenic acid/tung oil/ZIF-8 modified cotton (BTZC) fabric with anti-icing and self-cleaning features. This material manifests a unique nanoflower-shaped surface morphology, demonstrating exceptional superhydrophobicity with a static water contact angle (CA) of 162° and a sliding angle (SA) of 2°. Moreover, BTZC excels in its thermal stability, breathability, and resistance to icing. Equally impressive is its robust stability, as evidenced through rigorous testing under continuous washing and abrasion, sustained high and low temperatures, extreme pH environments, and immersion in various chemical solvents. BTZC presents as a fluorine-free, durable, economically viable alternative for outdoor textile applications, marking substantial progress in the utilization of biomass and metal-organic framework materials in the textile industry and promising implications for value enhancement.

Composite Superhydrophobic Coating with Transparency and Thermal Insulation for Glass Curtain Walls

In this paper, the preparation of a transparent superhydrophobic composite coating with a thermal insulation function using antimony-doped tin oxide (ATO) nanoparticles is proposed, which has advantages of being mass-producible and low-cost. In short, nanosilica and ATO are used as raw materials for constructing rough structures, and superhydrophobic coatings are obtained by mixing and adding binders after modification of each, which are then applied to the surface of various substrates by spraying to obtain a transparent superhydrophobic coating with a heat-insulating function. The specific role of each nanoparticle is discussed through comparative experiments that illustrate the mechanism by which the two particles construct rough structures. The coating achieves unique thermal insulation properties while possessing excellent superhydrophobicity (WCA of ∼163° and WSA of ∼3°) and high light transmission (∼70%). Heat-shielding experiments have demonstrated that the composite coating effectively reduces the room temperature by approximately 19% for the same irradiation time. The coating achieves a balanced improvement in visible transmittance, thermal insulation, and superhydrophobicity. In addition, the coating's self-cleaning properties, mechanical properties, chemical weathering resistance, high-temperature resistance, and anti-icing properties were verified through various experiments.

Superhydrophobic Solar-to-Thermal Materials Toward Cutting-Edge Applications

Solar-to-thermal conversion is a direct and effective way to absorb sunlight for heat via the rational design and control of photothermal materials. However, when exposed to water-existed conditions, the conventional solar-to-thermal performance may experience severe degradation owing to the high specific heat capacity of water. To tackle with the challenge, the water-repellent function is introduced to construct superhydrophobic solar-to-thermal materials (SSTMs) for achieving stable heating, and even, for creating new application possibilities under water droplets, sweat, seawater, and ice environments. An in-depth review of cutting-edge research of SSTMs is given, focusing on synergetic functions, typical construction methods, and cutting-edge potentials based on water medium. Moreover, the current challenges and future prospects based on SSTMs are also carefully discussed.

Tannic acid crosslinked chitosan/gelatin/SiO2 biopolymer film with superhydrophobic, antioxidant and UV resistance properties for prematuring fruit packaging

The environmental pollution caused by plastic films urgently requires the development of non-toxic, biodegradable, and renewable biopolymer films. However, the poor waterproof and UV resistance properties of biopolymer films have limited their application in fruit packaging. In this work, a novel tannic acid cross-linked chitosan/gelatin film with hydrophobic silica coating (CGTS) was prepared. Relying on the adhesion of tannic acid and gelatin to silica, the coating endows CGTS film with excellent superhydrophobic properties. Especially, the contact angle reaches a maximum value 152.6°. Meanwhile, tannic acid enhanced the mechanical strength (about 36.1 %) through the forming of hydrogen bonding and the network structure. The prepared CGTS films showed almost zero transmittance to ultraviolet light and exhibited excellent radical scavenging ability (∼76.5 %, DPPH). Hence, CGTS film is suitable as a novel multifunctional packaging material for the agriculture to protect premature fruits, or the food industry used in environments exposed to ultraviolet radiation and rainwater.

Smart and Sustainable Crop Protection: Design and Evaluation of a Novel α-Amylase-Responsive Nanopesticide for Effective Pest Control

In this study, an α-amylase-responsive controlled-release formulation was developed by capping polydopamine onto β-cyclodextrin-modified abamectin-loaded hollow mesoporous silica nanoparticles. The prepared Aba@HMS@CD@PDA were subjected to characterization using various analytical techniques. The findings revealed that Aba@HMS@CD@PDA, featuring a loading rate of 18.8 wt %, displayed noteworthy release behavior of abamectin in the presence of α-amylase. In comparison to abamectin EC, Aba@HMS@CD@PDA displayed a significantly foliar affinity and improved rainfastness on lotus leaves. The results of field trail demonstrated a significantly higher control efficacy against Spodoptera litura Fabricius compared to abamectin EC at all concentrations after 7, 14, and 21 days of spaying, showcasing the remarkable persistence of Aba@HMS@CD@PDA. These results underscore the potential of Aba@HMS@CD@PDA as a novel and persistently effective strategy for sustainable on-demand crop protection. The application of nanopesticides can enhance the effectiveness and efficiency of pesticide utilization, contributing to more sustainable agricultural practices.

Biomineralization-Inspired Copper Sulfide Decorated Aramid Textiles via In Situ Anchoring toward Versatile Wearable Thermal Management

Designing smart textiles for personal thermal management (PTM) is an effective strategy for thermoregulation and energy saving. However, the manufacture of versatile high-performance thermal management textiles for complex real-world environments remains a challenge due to the limitations of functional integration, material properties, and preparation procedures. In this study, an aramid fabric based on in situ anchored copper sulfide nanostructure is developed. The textile with excellent solar and Joule heating properties can effectively keep the body warm even at low energy inputs. Meanwhile, the reduced infrared emissivity of the textile decreases the thermal radiation losses and helps to maintain a constant body temperature. Impressively, the textile integrates superb electromagnetic shielding, near-complete UV protection properties, and ideal resistance to fire and bacteria. This work provides a simple strategy for fabricating multi-functional integrated wearable devices with flexibility and breathability, which is highly promising in versatile PTM applications.

An energy-free strategy to elevate anti-icing performance of superhydrophobic materials through interfacial airflow manipulation

Superhydrophobic surfaces demonstrate excellent anti-icing performance under static conditions. However, they show a marked decrease in icing time under real flight conditions. Here we develop an anti-icing strategy using ubiquitous wind field to improve the anti-icing efficiency of superhydrophobic surfaces during flight. We find that the icing mass on hierarchical superhydrophobic surface with a microstructure angle of 30° is at least 40% lower than that on the conventional superhydrophobic plate, which is attributed to the combined effects of microdroplet flow upwelling induced by interfacial airflow and microdroplet ejection driven by superhydrophobic characteristic. Meanwhile, the disordered arrangement of water molecules induced by the specific 30° angle also raises the energy barriers required for nucleation, resulting in an inhibition of the nucleation process. This strategy of microdroplet movement manipulation induced by interfacial airflow is expected to break through the anti-icing limitation of conventional superhydrophobic materials in service conditions and can further reduce the risk of icing on the aircraft surface.

Adaptive cooling strategy via human hair: High optothermal conversion efficiency of solar radiation into thermal dissipation

Natural species have developed complex nanostructures in a hierarchical pattern to control the absorption, reflection, or transmission of desired solar and infrared wavelengths. This bio-inspired structure is a promising method to manipulating solar energy and thermal management. In particular, human hair is used in this article to highlight the optothermal properties of bio-inspired structures. This study investigated how melanin, an effective solar absorber, and the structural morphology of aligned domains of keratin polymer chains, leading to a significant increase in solar path length, which effectively scatter and absorb solar radiation across the hair structure, as well as enhance thermal ramifications from solar absorption by fitting its radiative wavelength to atmospheric transmittance for high-yield radiative cooling with realistic human body thermal emission.

Ag Nanoparticles-Coated Shish-Kebab Superstructure Film for Wearable Heater

Passive and active wearable heaters have received widespread attention due to their efficient utilization of solar energy and all-weather heating capabilities, but the current challenges are their preparation processes being time-consuming and equipment expensive. Herein, a simple and facilitated preparation method for the multifunctional wearable heater was developed, which springs Ag nanoparticles on the shish-kebab superstructure film via deposited melanin-like polydopamine as the adhesive. The light absorption ability of the resultant wearable heater in the visible region can be significantly enhanced by the addition of polydopamine, realizing a highly efficient photothermal conversion ability. Accordingly, it can achieve rapid warming ability whether passive heating (up to 45 °C about 60 s at 100 mW/cm2) or active heating (up to 72 °C about 40 s at 0.6 V), compared to ordinary cotton fabric. In addition, it can realize a 6.3 °C temperature difference with Cotton, showing excellent heat preservation ability. This study demonstrates a simple and low-cost approach for the prepared shish-kebab superstructure-based wearable heaters.

Highly Efficient Photothermal Icephobic/de-Icing MOF-Based Micro and Nanostructured Surface

Photothermal materials have gained considerable attention in the field of anti-/de-icing due to its environmental friendliness and energy saving. However, it is always significantly challenging to obtain solar thermal materials with hierarchical structure and simultaneously demonstrate both the ultra-long icing delay ability and the superior photothermal de-icing ability. Here, a photothermal icephobic MOF-based micro and nanostructure surface (MOF-MNS) is presented, which consists of micron groove structure and fluorinated MOF nanowhiskers. The optimal MOF-M250 NS can achieve solar absorption of over 98% and produce a high temperature increment of 65.5 °C under 1-sun illumination. Such superior photothermal-conversion mechanism of MOF-M250 NS is elucidated in depth. In addition, the MOF-M250 NS generates an ultra-long icing delay time of ≈3960 s at -18 °C without solar illumination, achieving the longest delay time, which isn't reported before. Due to its excellent solar-to-heat conversation ability, accumulated ice and frost on MOF-M250 NS can be rapidly melted within 720 s under 1-sun illumination and it also holds a high de-icing rate of 5.8 kg m-2 h-1 . MOF-M250 NS possesses the versatility of mechanical robustness, chemical stability, and low temperature self-cleaning, which can synergistically reinforce the usage of icephobic surfaces in harsh conditions.

A Hierarchically Nanofibrous Self-Cleaning Textile for Efficient Personal Thermal Management in Severe Hot and Cold Environments

Climate change has recently caused more and more severe temperatures, inducing a growing demand for personal thermal management at outdoors. However, designing textiles that can achieve personal thermoregulation without energy consumption in severely hot and cold environments remains a huge challenge. Herein, a hierarchically nanofibrous (HNF) textile with improved thermal insulation and radiative thermal management functions is fabricated for efficient personal thermal management in severe temperatures. The textile consists of a radiative cooling layer, an intermediate thermal insulation layer, and a radiative heating layer, wherein the porous lignocellulose aerogel membrane (LCAM) as intermediate layer has low thermal conductivity (0.0366 W·m-1·K-1), ensuring less heat loss in cold weather and blocking external heat in hot weather. The introduction of polydimethylsiloxane (PDMS) increases the thermal emissivity (90.4%) of the radiative cooling layer in the atmospheric window and also endows it with a perfect self-cleaning performance. Solar absorptivity (80.1%) of the radiative heating layer is dramatically increased by adding only 0.05 wt% of carbon nanotubes (CNTs) into polyacrylonitrile. An outdoor test demonstrates that the HNF textile can achieve a temperature drop of 7.2 °C compared with white cotton in a hot environment and can be as high as 12.2 °C warmer than black cotton in a cold environment. In addition, the HNF textile possesses excellent moisture permeability, breathability, and directional perspiration performances, making it promising for personal thermal management in severely hot and cold environments.

Robust All-Waterborne Superhydrophobic Coating with Photothermal Deicing and Passive Anti-icing Properties

The compelling integration of superhydrophobic coatings with light-to-heat conversion capabilities has garnered substantial interest due to their dual functionality encompassing passive anti-icing and deicing attributes. However, the insufficient mechanical stability and the environmental and human health concerns stemming from the extensive use of organic solvents limit their practical application. In this study, an all-waterborne superhydrophobic photothermal coating (PCPAS) was prepared through the synergy of composite micro-nanoparticles derived from carbon nanotubes (CNT), polydopamine (PDA), and Ag particles with fluorine-containing polyacrylic emulsion (PFA). The PDA provided active sites for Ag+ reduction reaction and enhanced the interfacial interaction between CNT and Ag particles. The interfacial enhancement enabled the coating to maintain stable superhydrophobicity after 260 times sandpaper abrasion and 240 times tape peeling. Simultaneously, the composite micro-nanoparticle's light-to-heat conversion ability gave the coating excellent anti-icing/deicing capabilities. Under the condition of -20 °C, the freezing time of 30 μL of water droplets was extended to 392 s, and 2 × 2 × 2 cm ice cubes placed on the surface of the coating could completely melt after only 1142 s under simulated sunlight irradiation with a 1 kW/m2 intensity. In addition, the coating also had suitable self-cleaning properties and substrate applicability. The comprehensive attributes of this all-waterborne photothermal superhydrophobic coating render it a promising contender for anti-icing and deicing applications in challenging outdoor environments.

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.