It is important to understand the phase behavior of carbon dioxide in nanoporous structure, which could determine the pore shape and size distribution during a foaming process. In this work, we study the density fluctuations of carbon dioxide in a cylindrical nanopore by using classical density functional theory. It is found that the density fluctuations in solvophobic nanopore could exceed its bulk value by two orders of magnitude. The thickness of the layer with large density fluctuation is more than 3 nm to the wall. With decreasing the solvophobicity, the density fluctuation in nanopore could still be large with a decreased thickness of large fluctuation layer. The large density fluctuations happen only at the liquid side nearby the predrying line. These results are useful for the foaming process to manufacture porous material with a uniform pore shape and narrow size distribution.

中文翻译：

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圆柱形纳米孔中二氧化碳的密度波动

重要的是要了解二氧化碳在纳米孔结构中的相行为，这可以确定发泡过程中的孔形状和尺寸分布。在这项工作中，我们使用经典的密度泛函理论研究圆柱纳米孔中二氧化碳的密度波动。发现疏溶剂性纳米孔的密度波动可能超过其体积值两个数量级。具有大的密度波动的层的厚度相对于壁大于3nm。随着疏溶剂性的降低，纳米孔中的密度波动仍可能较大，而较大的波动层的厚度则减小。较大的密度波动仅发生在预干燥线附近的液体侧。