Molecularly Engineered 2D Amphiphilic Evaporator for Efficient Solar Evaporation via Hydrogen Bonding Disruption

Interfacial solar-driven evaporation offers a sustainable solution to freshwater scarcity. Although two-dimensional (2D) evaporators feature a simple architecture and facile fabrication, their efficiency is limited by high evaporation enthalpy. Here, we report a scalable, one-step solution-blending approach to fabricate a 2D ethylene–vinyl alcohol copolymer (EVOH)–cellulose nanofiber (CNF) substrate functionalized with polydopamine-coated Ti3C2Tx MXene (PDA-M/CE). EVOH’s low thermal conductivity and ambient-drying film formation with tunable thickness (150 μm – 2 mm), combined with CNF reinforcement and catechol-modified MXene’s photothermal efficiency, yield pronounced interfacial heat localization and a molecular-level hydrophilic–hydrophobic balance. Density functional theory (DFT) and Raman analysis confirm hydrogen-bond disruption and intermediate water formation, reducing the evaporation enthalpy to 788 kJ·kg–1. Under one sun illumination, PDA-M/CE achieves an evaporation rate of 3.39 kg·m–2·h–1 in 3.5 wt % NaCl brine, with an outdoor freshwater yield of 10.47 kg·m–2 in 8 h. This work provides a robust and cost-effective platform for solar desalination and wastewater treatment.