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

Abstract

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°, a rolling angle of 5 ± 1° and reflectance of ≈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.

Integrating Dual-Interfacial Liquid Metal Based Nanodroplet Architectures and Micro-Nanostructured Engineering for High Efficiency Solar Energy Harvesting

“…In terms of light management, the coupled light (in-and out-coupling) in the microstructure will form a cavity resonance as a standing wave inside the array type of trench, which is favorable to synergistically enhancing photothermal conversion. 9,56 To support this claim, Figure 4j displays the antireflection and absorption processes of incident sunlight. The formation of the template-induced micron-scale grating front surface with sufficiently rough texture contributes to reducing light losses by rays impinging multiple times upon the interface for all angles of incidence.…”

“…This strong broadband light absorptivity can be ascribed to the three main reasons: (1) the embedded LMP-rGOs characterized by wide size distribution; (2) orderly introduction of rGO shell and core–shell structure induced by PDA; and (3) construction of stepped micropyramid grating arrays for PVA-based absorber surface. In terms of light management, the coupled light (in- and out-coupling) in the microstructure will form a cavity resonance as a standing wave inside the array type of trench, which is favorable to synergistically enhancing photothermal conversion. , To support this claim, Figure j displays the antireflection and absorption processes of incident sunlight. The formation of the template-induced micron-scale grating front surface with sufficiently rough texture contributes to reducing light losses by rays impinging multiple times upon the interface for all angles of incidence.…”

Aqueous construction of raspberry-like ZIF-8 hierarchical structures with enhanced superhydrophobic performance

“…Because water droplets tend to be trapped in soft substrates, higher nonadherence is required. [48][49][50] As shown in Movie S4, † the water drop bouncing test was performed on untreated glass, aluminum foil, cotton, and paper, which were easily wetted by the water droplets (the contact moment of the water droplets with the solid surface was defined as 0 ms). Fig.…”

Recent advances in structural regulation and optimization of high-performance solar-driven interfacial evaporation systems

“…For example, the polyethylene/graphene foam with a micro-nanostructured surface reflected only ∼1.6% of sunlight and had a high water contact angle of 155 ± 2°. 217 The nickel template with micro-pyramid arrays was first used to construct a primary microstructure on the surface of the polyethylene/graphene nanosheets/NaCl composite by compression molding. After extracting NaCl, irregular pores appeared, and a secondary nanostructure was formed by spraying SiO 2 nanoparticles (Fig.…”