Chen Junlang, Dai Fangfang, Zhang Lingling, Xu Jing, Liu Wei, Zeng Songwei, Xu Can, Chen Liang, Dai Chaoqing
Department of Optical Engineering, Zhejiang A&F University, Lin'an 311300, China.
School of Information and Industry, Zhejiang A&F University, Lin'an 311300, China.
J Colloid Interface Sci. 2020 Jul 1;571:109-117. doi: 10.1016/j.jcis.2020.03.036. Epub 2020 Mar 10.
Improving the dispersion stability of graphene oxide (GO) suspensions is of great importance in many potential applications of GO, such as GO-based laminated membranes used for separation, printable electronics, and aqueous liquid crystals.
Molecular dynamics (MD) simulations and quantum chemistry (QC) calculations along with complementary experiments were performed to study the dispersion stability of GO in the mixtures of water and polar organic solvents (dimethyl sulfoxide (DMSO), ethanol, and acetone).
GO exhibits better dispersion stability in a solvent mixture than in pure water. The MD simulations uncover the underlying mechanism that mixed solvent layers are formed steadily on the surface of GO sheets and screen the interactions between them. QC calculations reveal that both DMSO and water form hydrogen bonds with the oxidized regions of GO. X-ray diffraction experiments confirm that the GO sheets are intercalated by DMSO and water molecules. Furthermore, the optimal ratio of the organic solvent to water is determined to achieve the best dispersion stability of GO through MD simulations. And such ratio is also verified by ultraviolet absorption spectral experiments. Thus, our findings provide a facile method to prepare GO suspensions with high dispersion stability.
提高氧化石墨烯（GO）悬浮液的分散稳定性在GO的许多潜在应用中至关重要，例如用于分离的基于GO的层压膜、可印刷电子产品和水性液晶。
进行了分子动力学（MD）模拟和量子化学（QC）计算以及补充实验，以研究GO在水和极性有机溶剂（二甲基亚砜（DMSO）、乙醇和丙酮）混合物中的分散稳定性。
GO在溶剂混合物中比在纯水中表现出更好的分散稳定性。MD模拟揭示了在GO片材表面稳定形成混合溶剂层并屏蔽它们之间相互作用的潜在机制。QC计算表明，DMSO和水都与GO的氧化区域形成氢键。X射线衍射实验证实，GO片层被DMSO和水分子插层。此外，通过MD模拟确定了有机溶剂与水的最佳比例，以实现GO的最佳分散稳定性。并且该比例也通过紫外吸收光谱实验得到验证。因此，我们的发现提供了一种制备具有高分散稳定性的GO悬浮液的简便方法。
