In this study, molecular dynamics simulations are performed to estimate the equilibrium pressure of liquid confined in nanopores. The simulations show that pressure is highly sensitive to the pore size and can significantly change from absolute positive to absolute negative values for a very small (0.1 nm) change in the pore size. The contribution from the solid–liquid interaction always dominates the pressure in the first liquid layer adjacent to the surface and the sensitiveness of pressure on the pore size is dependent on the atom distribution in the liquid layers. A surface influence number $S$ is introduced to quantitatively characterize the degree of the confinement. At constant system temperature, the $S$ number decreases with increasing pore size based on a power-law function. In nanopores with large S number, the pore liquid pressure is found to be independent of bulk liquid pressure, whereas in nanopores with small S number, the pore pressure is dependent and increases with bulk pressure.

中文翻译：

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纳米限制对液体压力的影响

在这项研究中，进行分子动力学模拟以估计限制在纳米孔中的液体的平衡压力。模拟表明，压力对孔径高度敏感，并且对于很小的孔径变化（0.1 nm），压力可以从绝对正值显着变化为绝对负值。固液相互作用的贡献始终控制着与表面相邻的第一液体层中的压力，并且压力对孔径的敏感性取决于液体层中的原子分布。表面影响数$\mathrm{小号}$引入以定量表征限制程度。在恒定的系统温度下，$\mathrm{小号}$基于幂律函数，孔数会随着孔径的增加而减少。在具有大S值的纳米孔中，发现孔液压力与整体液体压力无关，而在具有S数小的纳米孔中，孔压是相关的，并且随整体压力的增加而增加。