Sainz-Urruela Carlos, Vera-López Soledad, San Andrés María Paz, Díez-Pascual Ana M
Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, Faculty of Sciences, University of Alcalá, Alcalá de Henares, 28805 Madrid, Spain.
Institute of Chemistry Research, "Andrés M. del Río" (IQAR), University of Alcalá, Ctra. Madrid-Barcelona Km. 33.6, Alcalá de Henares, 28805 Madrid, Spain.
Nanomaterials (Basel). 2020 Dec 17;10(12):2532. doi: 10.3390/nano10122532.
Graphene oxide (GO) can be defined as a single monolayer of graphite with oxygen-containing functionalities such as epoxides, alcohols, and carboxylic acids. It is an interesting alternative to graphene for many applications due to its exceptional properties and feasibility of functionalization. In this study, electrochemically exfoliated graphene oxides (EGOs) with different amounts of surface groups, hence level of oxidation, were prepared by an electrochemical two-stage approach using graphite as raw material. A complete characterization of the EGOs was carried out in order to correlate their surface topography, interlayer spacing, defect content, and specific surface area (SSA) with their electrical, thermal, and mechanical properties. It has been found that the SSA has a direct relationship with the d-spacing. The EGOs electrical resistance decreases with increasing SSA while rises with increasing the D/G band intensity ratio in the Raman spectra, hence the defect content. Their thermal stability under both nitrogen and dry air atmospheres depends on both their oxidation level and defect content. Their macroscopic mechanical properties, namely the Young's modulus and tensile strength, are influenced by the defect content, while no correlation was found with their SSA or interlayer spacing. Young moduli values as high as 54 GPa have been measured, which corroborates that the developed method preserves the integrity of the graphene flakes. Understanding the structure-property relationships in these materials is useful for the design of modified GOs with controllable morphologies and properties for a wide range of applications in electrical/electronic devices.
氧化石墨烯（GO）可定义为具有诸如环氧化物、醇类和羧酸等含氧官能团的单层石墨。由于其优异的性能和功能化的可行性，它在许多应用中是石墨烯的一个有趣替代品。在本研究中，以石墨为原料，采用电化学两步法制备了具有不同表面基团数量（即氧化程度）的电化学剥离氧化石墨烯（EGO）。对EGO进行了全面表征，以便将其表面形貌、层间距、缺陷含量和比表面积（SSA）与其电学、热学和力学性能相关联。已发现SSA与d间距有直接关系。EGO的电阻随SSA增加而降低，而随拉曼光谱中D/G带强度比增加而升高，即随缺陷含量增加而升高。它们在氮气和干燥空气气氛下的热稳定性取决于其氧化程度和缺陷含量。它们的宏观力学性能，即杨氏模量和拉伸强度，受缺陷含量影响，而未发现与SSA或层间距相关。已测量到高达54 GPa的杨氏模量值，这证实了所开发的方法保留了石墨烯薄片的完整性。了解这些材料中的结构 - 性能关系对于设计具有可控形态和性能的改性GO以用于电气/电子设备中的广泛应用是有用的。
