Synthetic polymer fluids are increasingly being applied to support excavations in deep foundations. As these fluids are molecularly engineered, their underlying microstructure interaction with in situ soils significantly affect excavation stability and soil dispersion. However, little molecular‐scale research has been done on the rheological behavior of partially hydrolyzed polyacrylamides (PHPA) polymer fluids on the clay surface. Molecular models of the clay–polymer systems are constructed using PHPA on montmorillonite (MMT) clay surface. Initial rheological properties and soil‐binding ability at different shear rates, temperatures, and polymer concentrations are first studied using molecular dynamics (MD) simulations. It is found that the functional groups of PHPA can interact with the MMT surface and form a viscous film under the atomic interaction of hydrogen bonds, water bridges, and electrostatic attraction. The shear stress, σ increases with the shear rate and follows the power‐law model. And the viscosity, η decreases as the shear rate increases, which is consistent with the experimental trend. However, the σ and η decrease with the increase of temperature. And the action mode of PHPA concentration has been identified from the MD perspective. This work provides insight into the molecular mechanism for PHPA's rheology on the clay surface and their interaction.

中文翻译：

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分子模拟发现蒙脱石表面PHPA聚合物的流变性质和结合土壤的能力

合成聚合物流体越来越多地用于支撑深层基础中的开挖。由于这些流体是分子工程的，它们与原位土壤的潜在微观结构相互作用显着影响了开挖稳定性和土壤分散性。但是，关于在粘土表面上部分水解的聚丙烯酰胺（PHPA）聚合物流体的流变行为的分子规模研究很少。在蒙脱土（MMT）粘土表面上使用PHPA构建了粘土-聚合物系统的分子模型。首先使用分子动力学（MD）模拟研究在不同剪切速率，温度和聚合物浓度下的初始流变特性和土壤结合能力。发现在氢键，水桥和静电吸引的原子相互作用下，PHPA的官能团可与MMT表面相互作用并形成粘性膜。剪应力σ随着剪切速率的增加而增加，并遵循幂律模型。粘度η随着剪切速率的增加而减小，这与实验趋势一致。但是，σ和η随着温度的升高而降低。从MD的角度确定了PHPA浓度的作用方式。这项工作深入了解了PHPA在粘土表面上的流变性及其相互作用的分子机理。