Synthesis and Characterization. We proposed a single-step exfoliation and functionalization of BNNS using the amino acids-assisted ultrasonication method. A variety of amino acids with different side chain structures (Arg: positively charged; Trp: hydrophobic; Cys: S-containing; Asp: negative charged; Ser: polar uncharged) were tested. Different from previously reported work, 14 instead of Trp, Arg showed higher BNNS dispersion, yield, and stable solubility in water (Figure ). The more efficient exfoliation could be both the more favorable adsorption energy between Arg analog and boron nitride nanomaterials through π-stacking interactions, based on the theoretical calculation, and a much higher solubility of Arg than Trp at the same concentration. Therefore, after the optimization of Arg: bulk hBN ratio and ultrasonication time (see Table ), we proceeded with Arg for the following BNNS synthesis to form BNNS-Arg.