Hydrogel composite membranes with Marangoni-effect-induced surface patterning for salt-resistant solar-driven membrane distillation

Photothermal membrane distillation offers high desalination and strong environmental adaptability but suffers from pore-blocking salt crystallization that typically initiates at the pore edges. This work introduces a patterned membrane design that uses the Marangoni effect to restrict salt crystallization near the pore edges, sacrificing local flux to maintain overall vapor flux and ensure long-term operational stability. Under 1 kW/m 2 light and 0.6 mol/L NaCl, water production remains above 80% of the initial rate after 3 h, and the retention rate increases by 30%. The PTFE/PEGDA/graphene composite membrane effectively extends service life and boosts freshwater yield. Graphical abstract