Graphene oxide (GO) is widely used as a graphene conversion material for transparent electrodes and conductive films via reduction treatment. However, GOs are typically provided as mixtures that include various chemical structures and oxidation degrees, including strongly damaged ones. Since the contamination of these defective GOs decreases the conductivity of the resulting reduced GOs (rGOs), purification methods to concentrate low-defect GOs are required. In this study, we successfully separated GOs via aqueous two-phase extraction using a combination of polyethylene glycol (PEG) and octylphenol ethoxylate (OPE). Based on the difference in hydrophobicity caused by the number of carboxy groups, low-defect GOs and defective GOs were extracted into the hydrophobic PEG-rich phase and the hydrophilic OPE-rich phase, respectively. The low-defect GOs were then converted into rGOs, which exhibited higher conductivity than the non-extracted pristine GOs.

中文翻译：

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石墨烯氧化物的水两相萃取

氧化石墨烯（GO）通过还原处理被广泛用作透明电极和导电膜的石墨烯转化材料。但是，GO通常以包含各种化学结构和氧化度（包括严重损坏的化学结构）的混合物形式提供。由于这些缺陷GO的污染降低了所得还原GO（rGOs）的电导率，因此需要用于浓缩低缺陷GO的纯化方法。在这项研究中，我们成功地使用聚乙二醇（PEG）和辛基酚乙氧基化物（OPE）进行水相两相萃取成功分离了GO。基于由羧基数引起的疏水性的差异，将低缺陷的GO和有缺陷的GO分别提取到疏水的富含PEG的相和亲水的富含OPE的相中。