Development of novel icephobic surfaces using siloxane-modified epoxy nanocomposites

Abstract

• Superhydrophobic surfaces can be ineffective in combating ice accretion at subfreezing temperatures. • We developed a new durable icephobic coatings using epoxy-silica nanocomposite. • Surface chemistry and structure were modified by varying the nanoparticles’ concentration to attain durable icephobicity. • The coating can rebound supercooled droplets, reduce nucleation temperatures, delay freezing, and reduce ice adhesion. • The coating demonstrated excellent adhesion strength and consistent performance after repeated icing/thaw cycles. Ice accretion is the process by which a layer of ice builds up on solid objects that are exposed to freezing precipitation or supercooled cloud of droplets. In fact, the onset of ice accretion can be sudden and hazardous. This has motivated the development and deployment of icephobic coatings as an effective strategy to prevent or suppress ice accumulation on critical and functional surfaces. Previously, we reported a scalable technique to fabricate durable superhydrophobic coatings using siloxane-modified epoxy nanocomposites. Herein, we extend our earlier research by investigating the potential of using these nanocomposites as candidates for icephobicity. Accordingly, nanocomposites with varied silica nanoparticles’ concentrations were considered in our efforts to modify the surface energy and structure to transform the original superhydrophobic surface into an icephobic surface. Our results indicate that a highly superhydrophobic surface (25 wt% nanocomposite) can be ineffective in combating ice accretion at subfreezing temperatures. In contrast, a nanocomposite with a nanoparticles concentration of 35 wt% was found to (i) facilitate the full rebounding of supercooled droplets, while maintained at −10 °C, (ii) reduce the water nucleation temperature to −12 °C, (iii) delay the freezing process by ∼ 94 s at a temperature of −10 °C, and (iv) reduce the ice adhesion strength to ∼ 230 kPa. This comprehensive assessment of the different aspects of icephobicity was considered essential as it ensures the surface’s effectiveness against the variety of conditions that lead to ice accretion. Moreover, the developed nanocomposite coatings demonstrated excellent adhesion strength as well as consistent wettability and icephobicity after being subjected to numerous icing/thaw cycles. The outcome of our effort offers a great potential for the large-scale adoption of siloxane-modified nanocomposites in applications that require protection against ice accretion.