Abstract The aluminosilicate layers of the swelling clay mineral montmorillonite, and the saturated pores they delineate, control the mechanical properties and the transport of solutes in many natural and engineered environments. However, the structural basis of montmorillonite porosity remains poorly characterized due to the difficulty in visualizing hydrated samples in their native state. Here, we used cryogenic transmission electron microscopy (cryo-TEM) and cryo electron tomography (cryo-ET) to show that stacking defects within minimally altered, fully hydrated montmorillonite particles define multiscale porosity networks. Variations in layer lateral dimensions over tens to thousands of nanometers cause a range of topological and dynamic defects that generate pervasive curvature and introduce previously uncharacterized solute transport pathways. Observations of long-range rotational order between neighboring layers indicate that the layer-layer interactions that govern clay swelling involve three dimensional orienting forces that operate across nanoscale pores. These direct observations of the hierarchical structure of hydrated montmorillonite pore networks with nanoscale resolution reveal potentially general aspects of colloidal interactions in fluid-saturated clay minerals.

中文翻译：

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水合蒙脱石层大小的多分散性产生多尺度孔隙网络

摘要 膨胀粘土矿物蒙脱石的铝硅酸盐层及其描绘的饱和孔隙控制着许多自然和工程环境中的力学性能和溶质的传输。然而，由于难以在天然状态下可视化水合样品，蒙脱石孔隙度的结构基础仍未得到很好的表征。在这里，我们使用低温透射电子显微镜 (cryo-TEM) 和低温电子断层扫描 (cryo-ET) 来表明在最小改变的、完全水合的蒙脱石颗粒内的堆叠缺陷定义了多尺度孔隙率网络。数万至数千纳米的层横向尺寸变化会导致一系列拓扑和动态缺陷，这些缺陷会产生普遍的曲率并引入以前未表征的溶质传输途径。对相邻层之间的长程旋转顺序的观察表明，控制粘土膨胀的层间相互作用涉及跨越纳米级孔隙的三维定向力。这些对具有纳米级分辨率的水合蒙脱石孔隙网络层次结构的直接观察揭示了流体饱和粘土矿物中胶体相互作用的潜在一般方面。对相邻层之间的长程旋转顺序的观察表明，控制粘土膨胀的层间相互作用涉及跨越纳米级孔隙的三维定向力。这些对具有纳米级分辨率的水合蒙脱石孔隙网络层次结构的直接观察揭示了流体饱和粘土矿物中胶体相互作用的潜在一般方面。对相邻层之间的长程旋转顺序的观察表明，控制粘土膨胀的层间相互作用涉及跨越纳米级孔隙的三维定向力。这些对具有纳米级分辨率的水合蒙脱石孔隙网络层次结构的直接观察揭示了流体饱和粘土矿物中胶体相互作用的潜在一般方面。