Toward Sustainable Ice Protection: Photothermal and Icephobic Polyurethane Nanocomposite Coatings

Abstract

Ice accumulation on engineering surfaces operating in cold environments presents persistent safety, performance, and economic challenges across sectors such as aerospace, wind energy, transportation, and power infrastructure. Conventional de-icing strategies, including mechanical removal, chemical agents, and resistive heating, are often energy-intensive, costly, and environmentally harmful. In this context, polyurethane (PU)-based photothermal coatings offer a promising alternative by combining mechanical durability, environmental compatibility, and multifunctional ice-mitigation capability.

This study presents a simple and scalable strategy to develop multifunctional PU coatings with enhanced anti-icing and de-icing performance through the incorporation of iron oxide (Fe₃O₄) nanoparticles with tailored surface chemistry. Three nanoparticle systems were investigated: unmodified Fe₃O₄ (FPU), silicone oil–coated Fe₃O₄ (SiFPU), and hydroxyl-functionalized Fe₃O₄ (FOHPU), with loadings ranging from 0.5 to 10 wt%. The influence of nanoparticle functionalization on mechanical integrity, photothermal conversion efficiency, and icephobic behavior was systematically evaluated.

The coatings were fabricated and characterized using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), UV–Vis spectroscopy, and tensile testing. Photothermal performance was quantified via infrared thermography under 1-sun xenon illumination. Icephobic behavior was assessed using ice push-off tests conducted in a controlled cold-room environment, both with and without simulated solar irradiation. Coating durability was evaluated through repeated icing/de-icing cycles to assess long-term performance stability.

UV–Vis spectroscopy revealed significantly enhanced light absorption in nanoparticle-modified coatings, with silicone oil coating and hydroxyl functionalization reducing the Fe₃O₄ band gap by 2.3 and 2.55 eV, respectively. Surface-functionalized nanoparticles markedly improved icephobic performance. The 10FOHPU coating exhibited superior mechanical properties, achieving a Young’s modulus of 140 ± 6.2 MPa and a tensile strength of 6.3 ± 0.2 MPa, compared to 106.1 ± 4.1 MPa and 6.1 ± 0.4 MPa for pristine PU. ATR-FTIR analysis at sub-zero temperatures confirmed the formation of a quasi-liquid interfacial layer on FOHPU coatings. Notably, the 10SiFPU coating demonstrated the lowest ice adhesion strength (40 ± 8 kPa) after 20 minutes of light exposure. These results demonstrate that tailoring nanoparticle surface chemistry within PU matrices enables a synergistic enhancement of mechanical robustness, photothermal efficiency, and icephobic performance, offering a sustainable and energy-efficient solution for advanced ice-mitigation applications.