Kaczmarek Łukasz, Warga Tomasz, Makowicz Magdalena, Kyzioł Karol, Bucholc Bartosz, Majchrzycki Łukasz
Institute of Materials Science and Engineering, Lodz University of Technology, 90-924 Łódź, Poland.
Department of Physical Chemistry and Modelling, AGH University of Science and Technology, 30-059 Kraków, Poland.
Materials (Basel). 2020 Feb 3;13(3):681. doi: 10.3390/ma13030681.
This article presents the results of the cross-linking of oxidized flake graphene (GO) using hydrazine at room temperature. Conducting the process at temperatures up to 30 °C allowed to eliminate the phenomenon of thermal GO reduction to its non-oxidized form. In addition, based on the Infrared and Raman spectroscopy as well as X-ray photoelectron spectroscopy (XPS) analysis, the cross-linking ability of GO was observed depending on its size and degree of oxidation. These parameters were associated with selected physicochemical and electrical properties of obtained 3D structures. Three GO flakes sizes were tested in three different oxidation degrees. It was shown that, regardless of the size of GO, it is crucial to achieve a specific oxidation degree threshold which for the conducted tests was a >20% share of oxygen atoms in the whole structure. This value determines the ability to cross-link with hydrazine thanks to which it is possible to synthesize the spatial structure in which the π-π interactions among individual flakes are significantly reduced. This directly translates into the fact that the 3D structure shows an electrical resistance value in the range of 4-103 Ω, depending on the size and oxidation degree of the used material. The explanation of this phenomenon related to the electrical conductivity of 3D structures was confirmed based on the molecular modeling of the chemical structures.
本文介绍了室温下使用肼对氧化片状石墨烯（GO）进行交联的结果。在高达30°C的温度下进行该过程可消除GO热还原为非氧化形式的现象。此外，基于红外光谱、拉曼光谱以及X射线光电子能谱（XPS）分析，观察到GO的交联能力取决于其尺寸和氧化程度。这些参数与所得三维结构的选定物理化学和电学性质相关。在三种不同氧化程度下测试了三种GO薄片尺寸。结果表明，无论GO的尺寸如何，达到特定的氧化程度阈值至关重要，对于所进行的测试，该阈值是整个结构中氧原子的比例>20%。该值决定了与肼交联的能力，借此可以合成单个薄片之间π-π相互作用显著降低的空间结构。这直接导致三维结构的电阻值在4 - 103Ω范围内，具体取决于所用材料的尺寸和氧化程度。基于化学结构的分子建模证实了与三维结构电导率相关的这一现象的解释。
