Regional Centre of Advanced Technologies and Materials (RCPTM), Department of Physical Chemistry, Palacký University Olomouc, Olomouc 78371, Czech Republic.
Nanoscale. 2017 Jan 7;9(1):119-127. doi: 10.1039/c6nr05799c. Epub 2016 Oct 13.
Graphene oxide is one of the most studied nanomaterials owing to its huge application potential in many fields, including biomedicine, sensing, drug delivery, optical and optoelectronic technologies. However, a detailed description of the chemical composition and the extent of oxidation in graphene oxide remains a key challenge affecting its applicability and further development of new applications. Here, we report direct monitoring of the chemical oxidation of an individual graphene flake during ultraviolet/ozone treatment through in situ atomic force microscopy based on dynamic force mapping. The results showed that graphene oxidation expanded from the graphene edges to the entire graphene surface. The interaction force mapping results correlated well with X-ray photoelectron spectroscopy data quantifying the degree of chemical oxidation. Density functional theory calculations confirmed the specific interaction forces measured between a silicon tip and graphene oxide. The developed methodology can be used as a simple protocol for evaluating the chemical functionalization of other two-dimensional materials with covalently attached functional groups.
氧化石墨烯由于其在生物医学、传感、药物输送、光学和光电技术等众多领域的巨大应用潜力，成为研究最多的纳米材料之一。然而，详细描述氧化石墨烯的化学组成和氧化程度仍然是影响其适用性和进一步开发新应用的关键挑战。在这里，我们通过基于动态力映射的原位原子力显微镜报告了在紫外/臭氧处理过程中单个石墨烯薄片的化学氧化的直接监测。结果表明，石墨烯的氧化从石墨烯边缘扩展到整个石墨烯表面。相互作用力映射结果与 X 射线光电子能谱数据很好地相关，该数据量化了化学氧化的程度。密度泛函理论计算证实了在硅尖端和氧化石墨烯之间测量的特定相互作用力。所开发的方法可以用作评估具有共价键合官能团的其他二维材料的化学功能化的简单方案。
