Efficient and economical approach for flexible photothermal icephobic copper mesh with robust superhydrophobicity and active deicing property

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.

"Honeycomb" Photothermal Lubricated Porous Foam with Low-Temperature, Weak-Light, Anti-Icing/Deicing, and Long-Lasting Lubrication Properties

The prevalence of icing in nature has become a significant threat to human work and life, prompting the development of more energy-efficient active/passive combination anti-icing/deicing technologies. In order to overcome the disadvantage of the poor durability of superhydrophobic surfaces, lubricated surfaces inspired by nepenthes have been preferred. In this study, a paraffin and silicone oil-infused photothermal foam (PSIPF) with excellent overall performance was prepared using polypyrrole (PPy) as a photothermal conversion material, a mixture of silicone oil and paraffin as a lubricating fluid, and melamine foam (MF) as a carrier. The surface adhesive strength is less than 20 kPa at -20 °C, the melting time is only 1018 s at an irradiance of 200 W/m2 and -20 °C (0.2 sun), and surface droplets do not freeze within 1 h at -10 °C. Furthermore, the surface exhibits excellent mechanical durability and stability, maintaining optimal lubrication properties following repeated cycles of icing/deicing, water rinsing, and immersion for 2 days in acid and alkaline conditions. This photothermal lubricated surface with excellent anti-icing/deicing properties at low temperatures and in weak-light environments provides a wider range of applications for equipment at high latitudes and high altitudes.

Photothermal Solid Slippery Surfaces with Rapid Self-Healing, Improved Anti/De-Icing and Excellent Stability

Icing phenomenon that occurs universally in nature and industry gets a great impact on human life. Over the past decades, extensive efforts have been made for a wide range of anti-icing/deicing surfaces, but the preparation of anti-icing/deicing interfaces that combine stability, rapid self-healing and excellent anti-icing/deicing performance remains a challenge. In this study, a photothermal solid slippery surface with excellent comprehensive performance is prepared by integrating cellulose acetate film, carbon nanotubes with paraffin wax (CCP). Apart from the excellent anti-icing and deicing properties at -17 ± 1.0 °C under 1 sun illumination, the surface can further achieve deicing at temperatures as low as -22 ± 1.0 °C under infrared light. The fabricated surface also exhibits great stability when placed in harsh conditions such as underwater or ultra-low temperature environments for over 30 days. Even when suffering from physical damage, the prepared surface can rapidly self-repair under 1 sun illumination or near-infrared (NIR) illumination within 16.0 ± 1.5 s. Due to the rapid and repeatable self-healing performance, the lubricating properties of the interface material do not deteriorate even after 50 repeated abrasing-repairing cycles. The photothermal solid slippery surface possesses wide-ranging applications and commercial value at high latitude and altitude regions.

Icephobic/anti-icing properties of superhydrophobic surfaces

In the winter, icing on solid surfaces is a typical occurrence that may create a slew of hassles and even tragedies. Anti-icing surfaces are one of the effective solutions for this kind of problem. The roughness of a superhydrophobic surface traps air and weakens the contact between the solid surface and liquid water, allowing water droplets to be removed before freezing. At present, the conventional anti-icing methods including mechanical or thermal technology are not only surface structure unfriendly but also have the obsessions of low efficiency, high energy consumption and high manufacturing costs. Hence, developing a way to remove ice by just modifying the surface shape or chemical composition with a low surface energy is extremely desirable. Numerous attempts have been made to investigate the evolution of ice nucleation and icing on superhydrophobic surfaces under the direction of the ice nucleation hypothesis. In this paper, the research progress of ice nucleation in recent years is reviewed from theoretical and application. The icephobic surfaces are described using the wettability and classical nucleation theories. The benefits and drawbacks of anti-icing superhydrophobic surface are summarized, as well as deicing methods. Finally, several applications of ice phobic materials are illustrated, and some problems and challenges in the research field are discussed. We believed that this review will be useful in guiding future water freezing initiatives.

Textured and Hierarchically Constructed Polymer Micro- and Nanoparticles

Microfluidic techniques allow for the tailored construction of specific microparticles, which are becoming increasingly interesting and relevant. Here, using a microfluidic hole-plate-device and thermal-initiated free radical polymerization, submicrometer polymer particles with a highly textured surface were synthesized. Two types of monomers were applied: (1) methylmethacrylate (MMA) combined with crosslinkers and (2) divinylbenzene (DVB). Surface texture and morphology can be influenced by a series of parameters such as the monomer–crosslinker–solvent composition, surfactants, and additives. Generally, the most structured surfaces with the simultaneously most uniform particles were obtained in the DVB–toluene–nonionic-tensides system. In a second approach, poly-MMA (PMMA) particles were used to build aggregates with bigger polymer particles. For this purpose, tripropyleneglycolediacrylate (TPGDA) particles were synthesized in a microfluidic co-flow arrangement and polymerized by light- irradiation. Then, PMMA particles were assembled at their surface. In a third step, these composites were dispersed in an aqueous acrylamide–methylenebisacrylamide solution, which again was run through a co-flow-device and photopolymerized. As such, entities consisting of particles of three different size ranges—typically 0.7/30/600 µm—were obtained. The particles synthesized by both approaches are potentially suitable for loading with or incorporation of analytic probes or catalysts such as dyes or metals.

Carbon-Based Photothermal Superhydrophobic Materials with Hierarchical Structure Enhances the Anti-Icing and Photothermal Deicing Properties

Ice formation on the surface of outdoor equipment brings significant inconvenience to human life and production. Superhydrophobic materials with the micro-nanostructure are considered to be effective anti-icing materials. However, repeated icing and deicing processes will destroy the structure and lose anti-icing properties. Herein, low-cost, durable, high-efficiency photothermal superhydrophobic materials were prepared by electrochemical deposition and silanization treatment methods. Combined with the black-body property of carbon materials and the micro-nano hierarchical structure, the as-prepared material has excellent photothermal and superhydrophobic properties. The surface temperature can rise to 90 °C, and the freezing droplets can melt in 100 s under 100 mW/cm² of sunlight illumination. The superhydrophobic property endows the material with excellent anti-icing performance, and the icing delay time is as long as 3600 s. The melted water droplet can quickly roll off due to the low adhesion of the superhydrophobic surface, which avoids the refreezing of the melted droplet and enhances the photothermal conversion performance. We innovatively use the elemental tracer method to understand the melted water droplet roll off mechanism on inclined surfaces. In addition, the heat transfer model of anti-icing and photothermal deicing processes are established to confirm that the heat required for melting ice during the deicing process is mainly generated by photothermal materials. Finally, the feasibility of practical application of the material was verified by the anti-icing/deicing experiment of a wind turbine blade and ice/frost layer melting experiment. It concludes that the superior anti-icing and deicing properties are realized using the high photothermal conversion and excellent superhydrophobic properties of the prepared photothermal superhydrophobic materials. This study provides a perspective for constructing micro-nano hierarchical structures on the surface and combining them with the abundant solar energy in nature to develop photothermal anti-icing materials for practical application.