Long‐term‐durable anti‐icing superhydrophobic composite coatings

Fabrication and Experimental Study of Micro/Sub-Micro Porous Copper Coating for Anti-Icing Application

Micro and sub-micro-spherical copper powder slurries were elaborately prepared to fabricate different types of porous coating surfaces. These surfaces were further treated with low surface energy modification to obtain the superhydrophobic and slippery capacity. The surface wettability and chemical component were measured. The results showed that both the micro and sub-micro porous coating layer greatly increased the water-repellence capability of the substrate compared with the bare copper plate. Notably, the PFDTES-fluorinated coating surfaces yielded superhydrophobic ability against water under 0 °C with a contact angle of ~150° and a contact angle of hysteresis of ~7°. The contact angle results showed that the water repellency of the coating surface deteriorated with decreasing temperature from 10 °C to -20 °C, and the reason was probably recognized as the vapor condensation in the sub-cooled porous layer. The anti-icing test showed that the ice adhesion strengths of the micro and sub-micro-coated surfaces were 38.5 kPa and 30.2 kPa, producing a 62.8% and 72.7% decrease compared to the bare plate. The PFDTES-fluorinated and slippery liquid-infused porous coating surfaces both produced ultra-low ice adhesion strengths of 11.5-15.7 kPa compared with the other non-treated surfaces, which showed prominent properties for anti-icing and deicing requirement of the metallic surface.

Review on the recent development of durable superhydrophobic materials for practical applications

Biomimetic superhydrophobic surfaces show great potential in oil-water separation, anti-icing and self-cleaning. However, due to the instability caused by its fragile structure and non-durable superhydrophobicity, it is difficult to apply them in the actual field. Here, by introducing surface wettability and analysing the mechanism of superhydrophobic failure, it is concluded that the reason for the failure of the superhydrophobic surface comes from the transition of the surface energy and the hysteresis of the contact angle (CA). On the basis of this analysis, it is concluded that the principle of designing a durable superhydrophobic surface is to satisfy one of the following three points: improving the binding force between molecules, introducing durable materials and improving chemical durability. On this basis, a variety of preparation methods are proposed, such as assembly method and spray/dip coating method, and the design and preparation of a self-healing surface inspired by nature will also be included in the introduction. Last but not least, the preparation and application of a durable super-hydrophobic surface in oil-water separation, anti-icing and self-cleaning are also introduced in detail. This review reveals the conclusions and prospects of durable superhydrophobic surfaces, and aims to inspire more researchers to invest in this research.

Rapid fabrication of a dual-scale micro-nanostructured superhydrophobic aluminum surface with delayed condensation and ice formation properties

Aluminum (Al) is widely used in all forms of industry, including automobile, aerospace, transmission lines, and exchangers, and in general household appliances. Ice accumulation on Al surfaces may cause serious problems, especially during the winter, leading to critical damage to mechanical systems. In this study, we developed a superhydrophobic coating with anti-icing properties on an Al surface using a simple and cost-effective technique. The superhydrophobic dual-shape micro-/nanostructured (MN-) Al surface was fabricated by a facile chemical etching and an anodization method, followed by surface modification with polydimethylsiloxane (PDMS) via a simple thermal vapor deposition method. The static contact angle of the fabricated surface was more than 160 °C. Compared with the bare surface and the silicone oil-infused PDMS coating (SLIPS) on the MN-structured Al substrate, the fabricated superhydrophobic surface displayed excellent anti-icing. Ice formation on the superhydrophobic surface was delayed by 80 and 45 min at -5 °C and -10 °C, respectively, at a relative humidity of 80% ± 5%. The superhydrophobic surface demonstrated an increase of almost four and two times delay in icing time on the surface over bare and SLIPS surfaces, respectively. The coalescence induced jumping behavior of condensate water droplets was also investigated on the fabricated surfaces. The result indicates that the superhydrophobic surface can effectively delay ice/frost formation by the synergetic effect of surface morphology and the extremely low adhesive property of the surfaces, which allows the self-propelled jumping phenomenon at low temperature and high humidity. This proposed simple, fast, and cost-effective method could be applied to design large-scale anti-icing surfaces.