Mechanochemical synthesis and interfacial engineering of photothermal polymer composites for solar-driven water evaporation

Freshwater generation has been extensively studied to address the global freshwater scarcity issue, although designing a simple, inexpensive system with high efficiency and sustainability is complicated. Solar-driven water evaporation is a promising, highly efficient water purification strategy. This paper reports the synthesis of a hydrophilic conductive polymer and its carbon nanotube (CNT) composites for efficient solar-driven water evaporation via a quick mechanochemical process. Doped polydiphenylamine (PD) and its CNT composites were obtained by the simple grinding of an inexpensive eutectic-phase monomer with oxidants, doping agents, and oxidized CNTs. The obtained composites exhibited high photothermal efficiency (89.9%) and water evaporation rate (1.41 kg m⁻² h⁻¹) under 1 sun irradiation. Dual doping and introducing oxidized CNTs into PD enhanced the wettability, photothermal efficiency, and water evaporation performance. This study provides an effective strategy for the fast and facile fabrication of photothermal membranes for solar-driven freshwater generation.