Chitosan electrolyte hydrogel with low ice adhesion properties

Icephobic materials can prevent or reduce ice formation, e.g. by ensuring easy detachment, a desirable property for those applications where ice accumulation is critical to human safety. Herein, we develop a chitosan electrolyte hydrogel to create a bio-based surface with low ice adhesion. The chitosan electrolyte hydrogel is physically crosslinked and infused with salted water at concentrations from 4.5 to 30 g/L, including that of seawater (23 g/L). Depending on salt content in the hydrogel, we could obtain very low ice adhesion down to 140 kPa (at – 10°C). We hypothesize that the chitosan electrolyte hydrogel exploits the colligative properties of water avoiding the ice nucleation at the ice-hydrogel interface. To confirm the hypothesis, we investigate the chitosan electrolyte hydrogel structure by contact angles analysis, DSC, TGA, FTIR, XRD, and by rheometry for mechanical properties. We quantify the presence of non-freezing water, which creates a lubricating liquid water layer at the ice-hydrogel interface, affecting the ice detachment mechanism and lowering ice adhesion. In conclusion, the proposed chitosan electrolyte hydrogel presents a bio-based and cost-efficient strategy for ice detachment across various icing scenarios for systems operating in humid marine environments, such as offshore platforms and ships.