Bioinspired “Spindle Knot Effect” Integrated into Mixed-Matrix Nanofibrous Membranes for Highly Efficient Solar-to-Vapor Conversion

Abstract

The microstructure of photothermal interface materials for solar steam generation is crucial to simultaneously optimize the water transfer path and solar-to-vapor conversion efficiency; however, it remains a formidable challenge. Herein, bioinspired by the spindle knot structure of spider silk, spindleknotted nanofibrous mixed-matrix membranes are facilely prepared and exhibit highly efficient solar-to-vapor conversion due to the "spindle knot effect" that results from the localized solar-to-thermal conversion at the spindle knots and water's directional movement on the spindle knots' surface. The asprepared membrane achieves an evaporation rate of 2.41 kg m −2 h −1 with a conversion efficiency of 95.9% under 1 Sun and a maximum water production of 4.81 kg m −2 in 1 day. Besides, it can output a high electric power of 0.89 W m −2 to power small devices due to the Seebeck effect and exhibit strong ice removal performance. This work reports the bioinspired strategy for constructing multifunctional photothermal interface materials.