Polydopamine-mediated interfacial engineering of phase-change photothermal composites for synergistically enhanced thermal storage, conversion, and solar-driven anti-/de-icing

Photothermal materials are promising for anti-/de-icing, yet their practical application is limited by the intermittent nature of sunlight. Phase-change materials (PCMs) offer a solution by storing thermal energy, but composite systems often suffer from complex synthesis, high cost, and PCM leakage. Herein, we report a facile and low-cost phase-change photothermal composite (PDC2D) prepared via simple adsorption polymerization, using paraffin (PA) as the PCM, diatomite (DE) as the support, and carbon nanotubes (CNTs) and polydopamine (PDA) as photothermal agents. The introduced PDA significantly strengthens the interfacial interactions among the components, effectively suppressing PA leakage and concurrently enhancing the composite's thermal storage capacity (latent heat ~103 J/g), thermal conductivity, and broad-spectrum light absorption. When integrated PDC2D polydimethylsiloxane (PDMS) to fabricate a functional anti-/de-icing coating, the composite coating exhibits a high water contact angle (137.4°) and a markedly improved photothermal response, achieving a 5.9–11.4 °C higher surface temperature than pure PDMS under 1 sun irradiation. Consequently, water droplets on the coating show a threefold longer freezing time and a 50% shorter melting time. This excellent anti-/de-icing performance stems from the synergy of efficient photothermal conversion, thermal energy storage, and surface hydrophobicity, enabling effective ice management even without continuous light. This work provides a practical, low-cost strategy for developing sustainable, solar-driven ice-control materials.