Janus membranes derived from multi-shelled hollow spheres coated electrospun PVA membranes as phase change composites for photothermal conversion.

The development and preparation of multifunctional photothermal conversion materials has far-reaching significance for the utilization of solar energy resources in response to the energy crisis. Herein, we propose a Janus membrane for interfacial solar evaporation and phase change energy storage. The membranes were fabricated via combining the PVA film with multi-shelled hollow spheres (MHS). The membranes have asymmetric wettability, that is, one side is hydrophilic and the other side is hydrophobic. The as-resulted membranes obtain outstanding light absorption without further processing. According to these two advantages, the membranes were applied to solar evaporation. The evaporation rate of the membrane is 1.41 kg*mh and the evaporation efficiency is 92.4 % under 1sun irradiation. Moreover, the membrane prepared by impregnating 1-Hexadecanamine (HDA) into MHS possesses excellent tensile strength (2.21 MPa) and photothermal conversion ability. The light-to-thermal conversion efficiency can reach 81.9 % under 1sun irradiation. Therefore, the membranes have broad application prospects in the field of photothermal conversion.