Cost-Effective Fabrication of Micro-Nanostructured Superhydrophobic Polyethylene/Graphene Foam with Self-Floating, Optical Trapping, Acid-/Alkali Resistance for Efficient Photothermal Deicing and Interfacial Evaporation

Solar evaporation is one of the most attractive and sustainable approaches to address worldwide freshwater scarcity. Unfortunately, it is still a crucial challenge that needs to be confronted when the solar evaporator faces harsh application environments. Herein, a promising polymer molding method that combines melt blending and compression molding, namely micro extrusion compression molding, is proposed for the cost-effective fabrication of lightweight polyethylene/graphene nanosheets (PE/GNs) foam with interconnected vapor escape channels and surface micro-nanostructures. A contact angle of 155 +/- 2 degrees, a rolling angle of 5 +/- 1 degrees and reflectance of approximate to 1.6% in the wavelength range of 300-2500 nm appears on the micro-nanostructured PE/GNs foam surface. More interestingly, the micro-nanostructured PE/GNs foam surface can maintain a robust superhydrophobic state under dynamic impacting, high temperature and acid-/alkali solutions. These results mean that the micro-nanostructured PE/GNs foam surface possesses self-cleaning, anti-icing and photothermal deicing properties at the same time. Importantly, the foam exhibits an evaporation rate of 1.83 kg m(-2) h(-1) under 1 Sun illumination and excellent salt rejecting performance when it is used as a self-floating solar evaporator. The proposed method provides an ideal and industrialized approach for the mass production of solar evaporators suitable for practical application environments.

Automated summary

A new method using polymer molding is proposed to fabricate lightweight polyethylene/graphene nanosheets foam with a micro-nanostructured surface, providing self-cleaning, anti-icing, and photothermal deicing properties. As a self-floating solar evaporator, the foam exhibits excellent evaporation rate and salt rejecting performance.