Magnetic‐controllableJanus fibrous membranes with wind‐resistantfloatability for airflow‐enhancedsolar evaporation

Interfacial solar evaporation has been widely regarded as a promising pathway to desalinate seawater without secondary pollution and additional carbon emission. However, one of the challenges rarely considered is the floating stability and remote controllability of the evaporator in the face of wind and waves at the seawater surface. Herein, we demonstrate magnetic Janus membranes (MJMs) with remotely magnetic controllability and wind‐resistant floatation for enhanced interfacial solar evaporation in airflow condition. These membranes are fabricated by sequential electrospinning of a hydrophobic Fe3O4‐embedded polyvinylidene fluoride (PVDF) layer and a hydrophilic polyacrylonitrile (PAN) layer. Due to the superparamagnetism of Fe3O4, our MJMs can be remotely manipulated by a magnet and can float in situ with the aid of a magnetic field, even facing the blast of airflow with a speed of 1.75 m/s. Moreover, the MJMs realize an enhanced vapor diffusion under airflow (v= 0.5 m/s) and show a water evaporation rate of 1.39 ± 0.06 kg∙m−2∙h−1under one sun, which is 40.4% higher than that in windless condition. This work provides a promising material solution with magnetic design for the practical offshore application of Janus membranes in interfacial solar evaporation.