Different Approaches to Low-Wettable Materials for Freezing Environments: Design, Performance and Durability

Abstract

Ice nucleation and accretion leads to multiple problems such as freezing of the streets which can cause traffic collisions or people injuries, and collapse of high voltage power lines leading to black-out and icing of aircraft components, causing major aeronautic accidents. The most widespread strategies for the removal of accumulated ice layers result in most cases being expensive, time-consuming and hazardous for the environment. In this work we present the design of hydrophobic hybrid inorganic-organic coatings via Lotus leaf-like and slippery liquid infused porous surfaces (SLIPS) approaches with reduced, lasting wetting performance in cold environments. Static and dynamic wetting behavior was evaluated at room and sub-zero temperatures. The main target was the selection of the most suitable design approaches and formulations of coatings to be applied on metals or alloys when the contact time between the droplet and the material surface has to be minimized. In the temperature range from −10 to 0 °C, we report evidence of a stable hydrophobicity and a low water contact angle hysteresis (below 15°) of all the SLIPS developed. The surfaces’ ability to keep their wetting performance unchanged during the freeze/and frost/thaw durability cycles stood out as a key issue for further development at larger scale.

Durability of Slippery Liquid-Infused Surfaces: Challenges and Advances

“…The authors explained the findings based on the Dzyaloshinskii-Lifshitz-Pitaevskii model. They concluded that stronger Van der Waals forces in the alumina-based SLIPS led to stronger capillarity and better self-recovery in comparison to the silica-based SLIPS [119]. As can be seen, a hierarchical structure helps in both lubricant retention and re-distribution.…”

“…Hierarchical nanostructures produced higher capillary pressure within nanopores, which locked the lubricant more effectively within the nanostructures and led to a significant improvement in the durability of the surface. Boveri et al [119] used the sol-gel method to fabricate SLIPS with alumina and silica nanoparticles, resulting in a hierarchical structure with an organic coating. Fluorinated Krytox oil was chosen as the lubricant for its high repellency and exceptional durability below the freezing point.…”

Special Issue “Anti-Icing Coatings and Surfaces”

“…The problems related to ice adhesion on structures is a global annoyance which has caused and is still causing threat to industry and public safety in many parts of the world, including North American (USA, Canada), Asian (Japan, China) European and Scandinavian countries, as reflected by the research contributions in this Special Issue by authors from these countries who constantly strive to minimize its impacts [1][2][3][4][5][6][7][8][9][10]. World renowned experts have been addressing the ice adhesion issues with their advanced research and development and in the finding of advanced technologies to evaluate the adhesion phenomena, both theoretically and experimentally.…”

“…The ten contributions constituting this Special Issue are composed of the latest developments and the state of the art regarding ice adhesion, which are well elaborated for a wide range of readers, including research scientists, students and industrials, as well as the curious audience. These ten contributions originate from countries worldwide, namely, Canada (Quebec), Italy, Spain, China, Norway, Germany, Bulgaria and USA [1][2][3][4][5][6][7][8][9][10].…”

“…The article titled "Different Approaches to Low-Wettable Materials for Freezing Environments: Design, Performance and Durability" by Giulio Boveri et al presents a highly interesting observation on wettability behavior at sub-zero temperatures ranging from 0 and −10 • C and the stability of wettability in the said range on their lotus-leaf like metal surfaces [2]. The ability of their surfaces in maintaining their low wetting behavior during the freeze and frost/thaw durability cycles shows promise for large-scale developments for industrial uses.…”