Interdependence of Surface Roughness on Icephobic Performance: A Review

Multifunctional Anti-Icing Gel Surface with Enhanced Durability

Materials with low ice adhesion and long-lasting anti-icing properties remain an ongoing challenge in ultralow temperature environments (≤-30 °C). This study presents a gel material consisting of a polymer matrix (copolymer of polyurethane and acrylamide) and an anti-icing agent, ethylene glycol (EG), designed for anti-icing applications at ultralow temperatures. The surface shows a prolonged droplet freezing delay of ca. 322 s at -30 °C and frost resistance properties. It also exhibits an ice adhesion strength of 1.1 kPa at -10 °C and 39.8 kPa at -50 °C, resulting from the interaction between EG and water molecules that hinders the crystallization of ice as well as the significant mismatch between elastic gel and ice. In addition, the gel surface exhibits favorable anti-icing durability, with an ice adhesion strength below 20.0 kPa after 25 icing/deicing cycles and mechanical scratch tests. The gel demonstrates remarkable thermal durability, achieved through the H-bonds between the EG and polymer matrix. The H-bonds further enhance the anti-icing performance, thereby remarkably decreasing EG depletion and improving anti-icing durability. Overall, these properties suggest the potential application of this gel material in harsh environments including polar regions.

Asymmetrically Nanostructured 2D Janus Films Obtained from Pickering Emulsions Polymerized in a Langmuir-Blodgett Trough

Low-dimensional structures, such as two-dimensional (2D) Janus films, can be useful in studying fundamental interactions or in applications at the nanoscale. In this work, we report the fabrication of 2D polymer Janus films consisting of one smooth and another nanostructured facet on which silica nanoparticles (NPs) are self-assembled in a compact monolayer shield. The 2D films are made from Pickering emulsions of monomers in water, stabilized by NPs, which are spread over the surface of the water in a Langmuir-Blodgett trough. Following the spreading of the colloidosomes, oil droplets stabilized by NPs collapse, and the interfaces reorganize such that the NP monolayer is found exclusively at the oil/water interface. Upon compression followed by UV polymerization, a 2D solid film is formed, with one smooth and another nanostructured face. The film can be removed from the surface of the water and handled with tweezers. The 2D films exhibit different surface properties on the two sides, such as differences in water wettability. On the nanostructured side, water wettability can be tuned by tuning the surface energy of the nanoparticles, namely by changing their surface functional groups. Upon removal of NPs, the surface can be patterned with an array of circular traces.