Observation of extreme phase transition temperatures of water confined inside isolated carbon nanotubes
Observation of extreme phase transition temperatures of water confined inside isolated carbon nanotubes
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DOI：
10.1038/nnano.2016.254
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发表时间：
2017-03-01
影响因子：
38.3
通讯作者：
Strano, Michael S.
中科院分区：
文献类型：
--
作者：
Agrawal, Kumar Varoon;Shimizu, Steven;Strano, Michael S.
单个，孤立的碳纳米管内的流体相变会大大偏离经典热力学。这种行为可以研究冰纳米管及其潜在应用的探索。在这里，我们报告使用拉曼光谱法（Raman Spectroscopicy）报告了限制在不同直径（1.05、1.06、1.15、1.24、1.44和1.52 nm）的六个孤立碳纳米管内的水的相边界的测量。结果揭示了对直径的敏感性和冻结过渡的温度升高（比理论上预测的比较大100摄氏度）。动态的水填充和可逆的冰点过渡在径向呼吸模式频率下以2-5 cm（-1）的变化标记，揭示了可逆的融化到105-151摄氏度和87-117摄氏度和87-117摄氏度。碳纳米管分别。在1.44和1.52 nm纳米管中观察到了近型相位变化，分别在15-49摄氏度和3-30摄氏度之间进行了括号，而观察到-35摄氏度之间的1.15 nm纳米管的冰点抑郁症。 C.我们还发现，内部水相可逆地将纳米管的轴向导热性降低多达500％，从而使热通量的数字控制。
Fluid phase transitions inside single, isolated carbon nanotubes are predicted to deviate substantially from classical thermodynamics. This behaviour enables the study of ice nanotubes and the exploration of their potential applications. Here we report measurements of the phase boundaries of water confined within six isolated carbon nanotubes of different diameters (1.05, 1.06, 1.15, 1.24, 1.44 and 1.52 nm) using Raman spectroscopy. The results reveal an exquisite sensitivity to diameter and substantially larger temperature elevations of the freezing transition (by as much as 100 degrees C) than have been theoretically predicted. Dynamic water filling and reversible freezing transitions were marked by 2-5 cm(-1) shifts in the radial breathing mode frequency, revealing reversible melting bracketed to 105-151 degrees C and 87-117 degrees C for 1.05 and 1.06 nm single-walled carbon nanotubes, respectively. Near-ambient phase changes were observed for 1.44 and 1.52 nm nanotubes, bracketed between 15-49 degrees C and 3-30 degrees C, respectively, whereas the depression of the freezing point was observed for the 1.15 nm nanotube between -35 and 10 degrees C. We also find that the interior aqueous phase reversibly decreases the axial thermal conductivity of the nanotube by as much as 500%, allowing digital control of the heat flux.