Cho Han-Hee, Yang Hyunseung, Kang Dong Jin, Kim Bumjoon J
Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea.
ACS Appl Mater Interfaces. 2015 Apr 29;7(16):8615-21. doi: 10.1021/acsami.5b00729. Epub 2015 Apr 15.
The surface properties of graphene quantum dots (GQDs) control their dispersion and location within the matrices of organic molecules and polymers, thereby determining various properties of the hybrid materials. Herein, we developed a facile, one-step method for achieving systematic control of the surface properties of highly fluorescent GQDs. The surfaces of the as-synthesized hydrophilic GQDs were modified precisely depending on the number of grafted hydrophobic hexylamine. The geometry of the modified GQDs was envisioned by conducting simulations using density functional theory. In stark contrast to the pristine GQDs, the surface-modified GQDs can effectively stabilize oil-in-water Pickering emulsions and submicron-sized colloidal particles in mini-emulsion polymerization. These versatile GQD surfactants were also employed in liquid-solid systems; we demonstrated their use for tailoring the dispersion of graphite in methanol. Finally, the particles produced by the GQD surfactants were fluorescent due to luminescence of the GQDs, which offers great potential for various applications, including fluorescent sensors and imaging.
石墨烯量子点（GQDs）的表面性质控制着它们在有机分子和聚合物基质中的分散和位置，从而决定了杂化材料的各种性质。在此，我们开发了一种简便的一步法，用于实现对高荧光GQDs表面性质的系统控制。合成后的亲水性GQDs的表面根据接枝的疏水性己胺的数量进行精确修饰。通过使用密度泛函理论进行模拟，设想了修饰后GQDs的几何形状。与原始GQDs形成鲜明对比的是，表面修饰的GQDs可以在微乳液聚合中有效地稳定水包油型Pickering乳液和亚微米级胶体颗粒。这些多功能的GQD表面活性剂也被用于液-固体系；我们展示了它们用于调整石墨在甲醇中的分散性。最后，由GQD表面活性剂产生的颗粒由于GQDs的发光而具有荧光性，这为包括荧光传感器和成像在内的各种应用提供了巨大潜力。
