These images show the coral-like aluminum oxide nanostructure, composed of hierarchical small units with sizes of ∼1.5 μm, as well as the curled nanoplates that form on the surface of the units. The pore sizes are in the range of 2–140 nm in diameter. Beginning with aluminum and hydroxide, the researchers induced a series of reactions to produce aluminum oxide, or y-AlOOH. Al3++3OH–→AlOH3→AlOOH+H2O The scientists then created a solution of water, aluminum oxide, and ethylene glycol (EG). When the concentration of γ-AlOOH reached supersaturation, crystal nuclei would be formed in the solution and subsequently grow. The volume ratio of EG to water in the mixed solvent was very important; the results could only be obtained at VEG:VH2O=4:1. EG is a general capping organic solvent which adsorbed on the surface of γ-AlOOH crystal by hydrogen bonding, leading to preferential, nanoplate-like growth.The surface-adsorbed EG molecules would then inhibit the adsorption of other ions in solution and shield the surface charges (kown as the charge shielding effect). Finally, the charge differences between the nanoplates’ surfaces and edges induced by charge shielding effect drove the structure to form self-curled nanoplates and a coral-like structure. To read the full scientific abstract, visit Science Direct.