Mosquito's Compound Eyes as Inspiration for Fabrication of Conductive Superhydrophobic Nanocarbon Materials from Waste Wheat Straw

Converting waste wheat straw to conductive superhydrophobic nanocarbon materials is inspired by mosquitos compound eyes, and a one step pyrolysis process is used for controllable construction of micro/nanohierarchical structures. Their structures and hydrophobicity can be tuned efficiently by the annealing temperature. Scanning electron microscopy, elemental analysis, X-ray diffraction, laser Raman, Fourier transform infrared, and photoelectron spectroscopy analyses were used to reveal the structure of electrical conductive carbon materials (ECMs) and a possible mechanism of the nanostructures formation. These results indicate that there are big differences between the surface and the inner structure for the nanocarbon materials, and the releasing rates of a multicomponent gas at different annealing temperatures by further decomposition of waste wheat straw should be pivotal to the formation of nanostructures. There is also cause for superhydrophobicity and electroconductivity for the ECM-800. Considering the potential use of the novel ECM-800, a low-cost, green, sustainable, conductive, and superhydrophobic coating strategy was developed by dip-coating of the different substrates with a ECM-800/PDMS mixture, followed by thermal curing. The water contact angle of the prepared ECM-800/PDMS coating is greater than 160 degrees, while the sliding angle is less than 5 degrees, showing excellent superhydrophobicity as well as good mechanical robustness and water-repellency in the artificial rain tests simultaneously. In addition, a robust ECM-800 enables resistance to a variety of harsh environments, such as an ability to resist heat and UV aging as well as sustaining exposure to strong acid/alkaline corrosion. Moreover, this work should be conducive to the controllable construction of conductive superhydrophobic nanocarbon materials with well-defined structure, and open up a convenient sustainable way for disposal of waste biomass for production of value-added materials.