Polymethyl Methacrylate/Polypyrrole Porous Membranes Prepared by Breath Figure Method with Superior Salt Resistance for High‐Efficiency Interfacial Solar Evaporation

A simple method for the fabrication of the double‐layer and salt‐resistant evaporator consists of a porous structure polymethyl methacrylate/polypyrrole (PMMA/PPy) photothermal membrane as the top layer and plant fiber‐wrapped expanded polyethylene (EPE) foam as the insulating bottom layer is demonstrated for the first time for efficient solar‐driven interfacial evaporation. For the fabrication of the porous PMMA/PPy membranes, a straightforward and affordable breath figure approach is used. Owing to its porous structure with low tortuosity and large pore size, excellent insulation of the EPE sponge, and the strong light absorption of PPy coating, the as‐prepared PMMA/PPy evaporator exhibits a stable photothermal conversion efficiency of 95.3%, corresponding to a high evaporation rate of 1.65 kg m −2 h −1 , and outstanding salt resistance performance in 15%wt NaCl solution (evaporation rate of 1.54 kg m −2 h −1 ), under 1 sun irradiation, thus showing great potential for practical desalination application by combination with its simple, cost‐efficient, and easily scale‐up fabrication process. More importantly, the findings herein may also provide a versatile method for the design of novel photothermal materials with large pores using various polymers as substrates without limitation by shape or size only via a simple and “green” breath figure approach.