Abstract We have measured the translational and rotational diffusion coefficients of graphene oxide (GO) sheets in water by using dynamic light scattering (DLS) and depolarized DLS. We show that the GO sheets in dilute regime translate laterally in such a way that rigid-rods move perpendicularly to their axis direction. This discovery renders a facile method for the determination of the average lateral size of GO sheets by using DLS with the simple rod-model. The lateral size ( L ) determined by DLS is 20.15, 3.65, 1.79, and 1.09 μ m for samples with ultra-sonication exposure times of 0, 3, 12, and 60 min, respectively. The L is correlated with the critical LC concentration and the electrical percolation threshold. The size dependency of the critical LC concentration follows the scaling of the Onsager model if and only if L ≤ 3.65 μm. In the reduced GO (rGO) coated films, the electrically conductive networks are two dimension in percolation scaling law when L ≥ 3.65 μm, but the higher fractal dimension when L ≤ 1.79 μm. In the films having 85% light transmittance, the surface resistivity is 6.2 kΩ/sq when L ≥ 3.65 μm, and 60 kΩ/sq when L ≤ 1.79 μm.

中文翻译：

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氧化石墨烯在水中的横向扩散以及尺寸对分散体取向和电导率的影响

摘要 我们使用动态光散射 (DLS) 和去极化 DLS 测量了水中氧化石墨烯 (GO) 片的平移和旋转扩散系数。我们展示了稀释状态下的 GO 片以这样的方式横向平移，即刚性杆垂直于其轴方向移动。这一发现为通过使用带有简单棒模型的 DLS 确定 GO 片的平均横向尺寸提供了一种简便的方法。对于超声暴露时间为 0、3、12 和 60 分钟的样品，由 DLS 确定的横向尺寸 (L) 分别为 20.15、3.65、1.79 和 1.09 μ m。L 与临界 LC 浓度和电渗透阈值相关。当且仅当 L ≤ 3.65 μm 时，临界 LC 浓度的大小依赖性遵循 Onsager 模型的缩放比例。在还原的 GO (rGO) 涂层薄膜中，当 L ≥ 3.65 μm 时，导电网络在渗透缩放定律中是二维的，但当 L ≤ 1.79 μm 时，分形维数更高。在透光率为85%的薄膜中，当L≥3.65μm时表面电阻率为6.2kΩ/sq，当L≤1.79μm时为60kΩ/sq。