Graphitic nanoparticles, specifically, graphene oxide (GO) nanoflakes, are of major interest in the field of nanotechnology, with potential applications ranging from drug delivery systems to energy storage devices. These applications are possible largely because of the properties imparted by various functional groups attached to the GO surface by relatively simple production methods compared to pristine graphene. We investigated how varying the size and oxidation of GO flakes can affect their structural and dynamic properties in an aqueous solution. The all-atom modeling of the GO nanoflakes of different sizes suggested that the curvature and roughness of relatively small (3 × 3 nm) GO flakes are not affected by their degree of oxidation. However, the larger (7 × 7 nm) flakes exhibited an increase in surface roughness as their oxidation increased. The analysis of water structure around the graphitic nanoparticles revealed that the degree of oxidation does not affect the water dipole orientations past the first hydration layer. Nevertheless, oxygen functionalization induced a well-structured first hydration layer, which manifested in identifiable hydrophobic and hydrophilic patches on GO. The detailed all-atom models of GO nanoflakes will guide a rational design of functional graphitic nanoparticles for biomedical and industrial applications.

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尺寸和功能化对氧化石墨烯纳米片结构和性能的影响：计算机研究

石墨纳米粒子，特别是氧化石墨烯（GO）纳米片，是纳米技术领域的主要关注点，其潜在应用范围从药物输送系统到能量存储设备。这些应用之所以成为可能，很大程度上是因为与原始石墨烯相比，通过相对简单的生产方法附着在GO表面的各种官能团所赋予的特性。我们研究了改变 GO 薄片的尺寸和氧化如何影响其在水溶液中的结构和动态特性。不同尺寸的 GO 纳米薄片的全原子建模表明，相对较小（3 × 3 nm）的 GO 薄片的曲率和粗糙度不受其氧化程度的影响。然而，较大的（7 × 7 nm）薄片随着氧化程度的增加而表现出表面粗糙度的增加。对石墨纳米粒子周围的水结构的分析表明，氧化程度不会影响经过第一水化层的水偶极子方向。然而，氧功能化诱导了结构良好的第一水化层，这表现为 GO 上可识别的疏水性和亲水性斑块。GO 纳米片的详细全原子模型将指导生物医学和工业应用的功能性石墨纳米颗粒的合理设计。