UMR ENS-CNRS-UPMC 8640, Department of Chemistry, Ecole Normale Supérieure rue Lhomond, 75005 Paris (France).
Chemphyschem. 2014 Feb 24;15(3):521-9. doi: 10.1002/cphc.201300928. Epub 2014 Jan 21.
We present a detailed molecular-dynamics study of water reorientation and hydrogen-bond dynamics in a strong confinement situation, within the narrow pores of an all-silica Linde type A (LTA) zeolite. Two water loadings of the zeolite are compared with the bulk case. Water dynamics are retarded in this extreme hydrophobic confinement and the slowdown is more pronounced at higher water loading. We show that water reorientation proceeds mainly by large-amplitude angular jumps, whose mechanism is similar to that determined in the bulk. The slowdown upon hydrophobic confinement arises predominantly from an excluded-volume effect on the large fraction of water molecules lying at the interface with the zeolite matrix, with an additional minor contribution coming from a structuring effect induced by the confinement.
我们呈现了一项详细的分子动力学研究，探讨了在强约束情况下，全硅 Linde 型 A（LTA）沸石狭窄孔隙内水的重新取向和氢键动力学。我们比较了沸石的两种水负载情况与本体情况。在这种极端疏水性约束下，水动力学受到阻碍，并且在更高的水负载下，减速更为明显。我们表明，水的重新取向主要通过大振幅角跳跃来进行，其机制与在本体中确定的机制相似。在疏水性约束下的减速主要源于对与沸石基质界面处的大量水分子的排除体积效应，另外还有一小部分来自约束引起的结构效应。
