Charge transfer and thermal conduction mechanisms in superhydrophobic Gr-TiO₂ photothermal coatings for high-efficiency deicing

In response to the surface icing issues of infrastructure and industrial equipment in extreme low-temperature environments, this study overcomes the energy consumption and durability limitations of traditional anti-icing/de-icing technologies by developing a scalable photothermal-superhydrophobic dual-functional composite coating. The coating is constructed through a “surface-anchored assembly” strategy: graphene (Gr) with few layers is used as the photothermal conversion core, which is modified by polydopamine (PDA) and covalently bonded with octyltriethoxysilane (OTES)-modified titanium dioxide (TiO₂). This is then anchored onto a semi-cured epoxy resin matrix, achieving efficient enrichment and firm binding of functional particles on the surface. The resulting coating exhibits both broad-spectrum photothermal response and mechanically stable superhydrophobic properties (static contact angle >155°, − <5°), significantly enhancing anti-icing/de-icing performance. Density functional theory (DFT) calculations reveal the charge transfer mechanism driven by the work function difference (ΔΦ = 0.64 eV) at the Gr-TiO₂ interface, explaining the enhanced photothermal performance at the microscopic level. Moreover, the heat transfer mechanism during the anti-icing/de-icing process is analyzed through a thermal conduction model. This work provides an efficient, stable, and scalable solution for anti-icing/de-icing in extreme environments through a three-dimensional synergy of material design, process innovation, and mechanism analysis. • Scalable epoxy-based coating with superhydrophobic and photothermal functions • Graphene-TiO₂ hybrids provide hierarchical roughness and solar absorption. • E-GT5 shows WCA ≈ 159°, SA < 5°, stable after abrasion and tape tests. • Photothermal surface fully de-ices at −15 °C within 257 s under 1-sun light. • DFT reveals charge-transfer mechanism for photothermal enhancement.