Liquefied-chitin polyurethane foam construction of high-efficiency solar evaporator for seawater purification

As key platforms for efficient photothermal conversion and water evaporation in solar water desalination processes, the design of photothermal interface materials have become an important topic. In this study, we designed an interfacial solar evaporator with liquefied-chitin PU foams as the base material. In this structure, polyaniline and polypyrrole convert solar energy in thermal energy. After the in-situ generation of hydrogel in the polyurethane foam to reduce the evaporation enthalpy of water and rapid evaporation of water. Liquefied-chitin make a PU foam with low thermal conductivity, reduce the heat loss of the water. Notably, the excellent antibacterial property of liquefied-chitin PU foam can make the photothermal material less likely to grow bacteria in the water and affect the photothermal evaporation efficiency. The water evaporation rates of PANi/PAM and PPy/PAM reached 2.18 and 2.38 kg m(-2) h(-1) under 1 solar irradiation, with photothermal conversion efficiencies of 136.9% and 149.4%, respectively. This study provides a simple method for converting polymers-based foam into efficient solar thermal materials for solar-driven desalination-related applications.