Ice-responsive Coatings: Evaluating the effect of Hydrogen bond donors on Deep eutectic solvents/Ionic liquids Anti-icing efficiency

Abstract

Although there has been pioneering research on the anti-icing properties of Ionic liquids (ILs) and Deep Eutectic Solvents (DESs), coatings based on these materials are still in the early stages of development. Given the limited understanding of DESs in anti-icing applications, we investigated the role of hydrogen bond donors (HBDs) within DESs, focusing on their hydrophilicity and hydrophobicity. After conducting a comprehensive study using advanced characterization techniques, including ATR-FTIR, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) analysis, and wettability measurements, our findings demonstrate that DESs can be effectively introduced as ice-responsive components on a surface, significantly improving their anti-icing performance. Our comparative analysis showed that the introduction of hydrophobic HBDs into DES-based coatings reduced ice adhesion strength to 13 kPa, while maintaining an ice formation temperature of −35 °C. Despite plasticising characteristic of DESs, notably, the mechanical properties, including tensile strength, remained consistent with the neat coating, though with enhanced elongation at break. Solid-state NMR spectroscopy revealed the formation of a thicker quasi-liquid layer (QLL) on the surface of coatings containing hydrophobic HBDs, which was further confirmed by low-temperature ATR-FTIR analysis. Moreover, these coatings exhibited modified frost formation patterns, leading to increased resistance to frost buildup over multiple cycles. Ice adhesion strength of coatings was examined against accelerated weathering, icing/de-icing cycles, as well. This study presents a novel approach for designing sustainable, high-performance icephobic coatings, emphasizing the potential of DESs as effective ice-responsive components in achieving superior anti-icing and anti-frosting capabilities.