Three-dimensional solvation structure of ethanol on carbonate minerals
Three-dimensional solvation structure of ethanol on carbonate minerals
复制标题
DOI：
10.3762/bjnano.11.74
复制
发表时间：
2020-06-10
影响因子：
3.1
通讯作者：
Kuehnle, Angelika
中科院分区：
文献类型：
--
作者：
Soengen, Hagen;Jaques, Ygor Morais;Kuehnle, Angelika
方解石和菱镁矿是地壳的重要矿物成分。在含水环境中，这些碳酸盐通常暴露出它们最稳定的解理面，即（10.4）面。众所周知，这些表面与各种各样的有机分子相互作用，这可能导致表面重组。这一过程对生物矿物的形成起着决定性的作用。随着3D原子力显微镜（AFM）的发展，现在可以以前所未有的分子分辨率对固液界面进行成像。然而，大多数的三维原子力显微镜的研究都集中在碳酸盐表面的水的安排。在这里，我们提出了一个分析的组装乙醇-一个有机分子与一个单一的羟基-在方解石和菱镁矿（10.4）的表面，通过使用高分辨率的三维原子力显微镜和分子动力学（MD）模拟。在一个单一的AFM数据集，我们能够解决的第一个横向有序的溶剂化层的方解石表面上的乙醇，以及以下的溶剂化层，显示没有横向顺序。我们的实验结果是在良好的协议与MD模拟。横向顺序的质的差异可以通过不同的化学环境来理解：虽然第一层在离子碳酸盐表面上采用特定的结合位置，但第二层位于有机乙基层的顶部。方解石和菱镁矿的比较揭示了一个定性相似的乙醇安排的碳酸盐，这表明这一发现的一般性质。
Calcite and magnesite are important mineral constituents of the earth's crust. In aqueous environments, these carbonates typically expose their most stable cleavage plane, the (10.4) surface. It is known that these surfaces interact with a large variety of organic molecules, which can result in surface restructuring. This process is decisive for the formation of biominerals. With the development of 3D atomic force microscopy (AFM) it is now possible to image solid-liquid interfaces with unprecedented molecular resolution. However, the majority of 3D AFM studies have been focused on the arrangement of water at carbonate surfaces. Here, we present an analysis of the assembly of ethanol - an organic molecule with a single hydroxy group - at the calcite and magnesite (10.4) surfaces by using high-resolution 3D AFM and molecular dynamics (MD) simulations. Within a single AFM data set we are able to resolve both the first laterally ordered solvation layer of ethanol on the calcite surface as well as the following solvation layers that show no lateral order. Our experimental results are in excellent agreement with MD simulations. The qualitative difference in the lateral order can be understood by the differing chemical environment: While the first layer adopts specific binding positions on the ionic carbonate surface, the second layer resides on top of the organic ethyl layer. A comparison of calcite and magnesite reveals a qualitatively similar ethanol arrangement on both carbonates, indicating the general nature of this finding.