A multifunctional superhydrophobic phase‐change photothermal coating for concrete anti‐icing

Abstract Superhydrophobic coatings meet the urgent need for anti‐icing infrastructure in low‐temperature environments but suffer limited functionality and easy failure. Carbon nanotubes (CNTs) with highly efficient photothermal conversion properties can address these issues when endowed with superhydrophobicity. However, CNTs face challenges in modification and functional failure without light. This study proposes a simple strategy to endow CNTs with superhydrophobic and phase‐change properties, affording CNTs with superhydrophobic photothermal phase‐change functions. The phase‐change superhydrophobic photothermal CNT (PSC) particle size distribution was optimized to 4–6 μm, effectively reducing CNT agglomeration tendency. The PSC exhibited good phase‐change enthalpy, with a 53% phase‐change material adsorption rate. Superhydrophobic coatings based on PSC were prepared via a two‐step method. The primer performed best with a 10% silicon carbide to epoxy resin mass ratio. Considering performance and economy, optimal coating performance occurred with 100 mg of PSC in the topcoat. The PSC coating achieved a 156.7° contact angle and a rolling angle of only 3.4°. It can rapidly warm from −10 to 50 °C under one solar intensity. The coating exhibits excellent robustness across extreme environments, extending droplet freezing time by 10‐fold at −10 °C and quickly melting under one sun intensity. This research will further advance the development of CNT‐based superhydrophobic photothermal coatings and promote their application in infrastructure sectors, particularly for cement concrete. © 2024 Society of Chemical Industry.