Tang Xiao-Ping, Wang Jing-Chen, Cary Lewis W, Kleinhammes Alfred, Wu Yue
Department of Physics, University of Nevada, Reno, Nevada 89557, USA.
J Am Chem Soc. 2005 Jun 29;127(25):9255-9. doi: 10.1021/ja051628i.
This work investigated the nanoconfinement effect on the molecular dynamics and phase transition of confined benzene inside titanate nanotubes with a uniform inner diameter of approximately 5.3 nm. For 13C-enriched organics, the 13C nuclear spin-spin relaxation was demonstrated as a sensitive tool to differentiate molecular translational motion and reorientation and, thus, was shown to be advantageous over the commonly employed 1H and 2H NMR for studying complex phase diagram, specifically, for separating the phase behavior of translational motion and the phase behavior of molecular reorientation. In such an approach, the melting of translational motion of confined benzene was explicitly observed to take place in a broad temperature range below the bulk melting temperature. The abrupt change of the 13C nuclear spin-spin relaxation time of the confined liquid benzene at about 260 K suggested that nanoconfinement induced two topologically distinct liquid phases.
这项工作研究了内径约为5.3纳米的钛酸盐纳米管内受限苯的分子动力学和相变的纳米限域效应。对于富含13C的有机物，13C核自旋-自旋弛豫被证明是区分分子平移运动和重取向的灵敏工具，因此，在研究复杂相图时，特别是在分离平移运动的相行为和分子重取向的相行为方面，它比常用的1H和2H NMR更具优势。在这种方法中，明确观察到受限苯的平移运动在低于本体熔点的较宽温度范围内发生熔化。受限液态苯在约260 K时13C核自旋-自旋弛豫时间的突然变化表明，纳米限域诱导了两种拓扑结构不同的液相。
