TY - EJOU AU - Li, Zheng AU - Li, Xiaohan AU - Yin, Qiang AU - Xu, Jingkun TI - Polydopamine-Coated Waste Cardboard Roll Evaporator for High-Performance Solar Desalination T2 - Journal of Polymer Materials PY - VL - IS - SN - 0976-3449 AB - Global freshwater scarcity has stimulated increasing interest in solar-driven interfacial evaporation for decentralized water purification. However, the development of low-cost evaporators that simultaneously achieve efficient photothermal conversion, continuous water supply, and functional separation of light harvesting and water transport remains a major challenge. Herein, we report a waste-cardboard-derived Janus cylindrical evaporator that integrates spatially separated photothermal conversion and water transport functions through a simple edge-immersion polydopamine (PDA) coating strategy followed by a rolling process. The PDA-coated upper region serves as a broad-band light absorber with a solar absorption exceeding 95% across 250–2500 nm and exhibits hydrophilicity, while the uncoated lower region retains the natural capillary network of cellulose fibers for continuous water supply. Under one-sun illumination, the evaporator delivers an evaporation rate of 2.07 kg m−2 h−1 with a photothermal conversion efficiency of 88.1%. In practical tests, it achieves over 99.9% rejection of primary ions (Na+, Mg2+, K+, Ca2+) and removes organic dyes with efficiencies exceeding 99%. This work presents a sustainable “waste-to-clean-water” strategy that valorizes discarded cardboard, offering a promising pathway toward decentralized and low-cost solar water purification. KW - Solar interfacial evaporation; waste cardboard; polydopamine; Janus evaporator; sea-water desalination DO - 10.32604/jpm.2026.087145