Centre For Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore, 560 012, India.
J Chem Phys. 2011 Mar 28;134(12):124105. doi: 10.1063/1.3571007.
Experiments and computer simulations demonstrate that water spontaneously fills the hydrophobic cavity of a carbon nanotube. To gain a quantitative thermodynamic understanding of this phenomenon, we use the recently developed two phase thermodynamics method to compute translational and rotational entropies of confined water molecules inside single-walled carbon nanotubes and show that the increase in energy of a water molecule inside the nanotube is compensated by the gain in its rotational entropy. The confined water is in equilibrium with the bulk water and the Helmholtz free energy per water molecule of confined water is the same as that in the bulk within the accuracy of the simulation results. A comparison of translational and rotational spectra of water molecules confined in carbon nanotubes with that of bulk water shows significant shifts in the positions of the spectral peaks that are directly related to the tube radius.
实验和计算机模拟表明，水会自发地填充碳纳米管的疏水腔。为了从定量热力学角度理解这一现象，我们使用最近开发的两相热力学方法来计算单壁碳纳米管内受限水分子的平动和转动熵，并表明纳米管内水分子的能量增加被其转动熵的增加所补偿。受限水与体相水处于平衡状态，并且受限水每分子的亥姆霍兹自由能与体相水的自由能在模拟结果的精度范围内相同。受限碳纳米管内水分子的平动和转动光谱与体相水的比较表明，光谱峰的位置发生了显著的移动，这与管半径直接相关。
