Charles University in Prague, Faculty of Mathematics and Physics, Prague, Czech Republic.
J Mol Model. 2009 Nov;15(11):1391-6. doi: 10.1007/s00894-009-0507-0. Epub 2009 May 6.
The surface area of various types of montmorillonites (MMT) with different values of layer charge plays a very important role in surface arrangement of methylene blue cations (MB). Photoluminescence measurements can be strongly or partially influenced by this surface arrangement of cations. For these reasons and on the basis of our previous results, molecular simulations were performed for various types of montmorillonites covered with methylene blue cations. Adsorption of methylene blue cations on Na-Wyoming MMT surface is different from Ca-Cheto MMT. In the case of Wyoming with a lower layer charge, MB cations lie parallel to the silicate layer for all investigated samples. On the other hand, Cheto surface is covered with a higher amount of MB cations. The results obtained from molecular modeling indicate that MB lies parallel to low loading case and become tilted with respect to layer for a higher loading. Moreover, a higher amount of MB cations covering the silicate layer are much less energy-stable. A higher loading of MB cations leads to aggregates but at low loading MB cations degrade to monomers.
各种类型的蒙脱土（MMT）的层电荷值不同，其表面面积在亚甲蓝阳离子（MB）的表面排列中起着非常重要的作用。 光致发光测量可能会受到这种阳离子表面排列的强烈或部分影响。 基于这些原因以及我们之前的结果，对各种类型的蒙脱土进行了覆盖有亚甲蓝阳离子的分子模拟。 亚甲蓝阳离子在钠-怀俄明蒙脱土表面上的吸附与钙-切托蒙脱土不同。 在层电荷较低的怀俄明州的情况下，对于所有研究的样品，MB 阳离子都平行于硅酸盐层。 另一方面，切托表面覆盖有更多的 MB 阳离子。 分子建模得到的结果表明，MB 平行于低负载情况，对于更高的负载，MB 相对于层倾斜。 此外，覆盖硅酸盐层的 MB 阳离子数量越多，能量稳定性越低。 较高负载的 MB 阳离子会导致聚集，但在低负载的情况下，MB 阳离子会降解为单体。
