Chemical Engineering Journal, Vol.369, 1040-1048, 2019
Constructing hierarchically hydrophilic/superhydrophobic ZIF-8 pattern on soy protein towards a biomimetic efficient water harvesting material
Inspired by the Stenocara beetle that can collect water from moist air in the Namib desert, here, we propose a simple dynamic control of crystal growth of ZIF on a natural polymer, soy protein. By adjusting the precursor concentration as well as the crystal growth time, hierarchical micro-/nano-crystals are constructed on the protein film surface. Taking advantage of the size difference of such crystals, selectively hydrophobic modification with a low surface-energy agent, stearic acid, can be performed on the surface, creating controllably hydrophilic/superhydrophobic patterns in favor of efficient water harvesting from fog. The effects of the as-prepared patterns on the water condensation behavior and collection efficiency are investigated; the maximum water collection efficiency, notably, can reach as high as 917.6 mg.cm(-2).h(-1). The results suggest that the biomimetic films hold a potential application in atmospheric water collection and the simple pattern-constructing approach is helpful to develop functional surface-patterned materials.