Reactive Molecular Dynamics Simulations of Thermal and Shear-Driven Oligomerization
Reactive Molecular Dynamics Simulations of Thermal and Shear-Driven Oligomerization
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DOI：
10.1016/j.apsusc.2022.153209
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发表时间：
2022-03
影响因子：
6.7
通讯作者：
Fakhrul H Bhuiyan;Seong H. Kim;A. Martini
中科院分区：
文献类型：
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作者：
Fakhrul H Bhuiyan;Seong H. Kim;A. Martini
机械化学反应在许多制造、摩擦学和合成过程中起着关键作用。通常，这些反应发生在滑动界面上，这使得它们难以通过实验进行研究。由于反应物种类同时受到摩擦加热和机械应力的影响，因此这种反应还没有完全理解。在这里，由热，正应力和剪切应力驱动的反应途径进行了研究，使用反应分子动力学模拟的α-蒎烯分子在二氧化硅上的机械化学齐聚。结果表明，剪切应力是摩擦条件下低聚反应的关键驱动因素。单独的正常应激对于诱导任何反应都是无效的，并且只有在非常高的温度下才能热驱动低聚反应。反应途径的分析表明，剪切可以激活多种机制，是无法访问的热。键长和二面角的计算表明，这种激活是伴随着反应物种的物理变形。反应分子动力学模拟的结果为机械化学反应的活化机制提供了重要的见解，这些机制可以指导材料和工艺的设计，并具有优化和潜在的可调剪切诱导反应。
Mechanochemical reactions play a critical role in many manufacturing, tribological, and synthesis processes. Often, these reactions happen at a sliding interface which makes them difficult to study experimentally. Such reactions are not fully understood since the reactant species are subject to frictional heating and mechanical stress simultaneously. Here, reaction pathways driven by heat, normal stress, and shear stress were investigated using reactive molecular dynamics simulations of mechanochemical oligomerization of α-pinene molecules on silica. Results identified shear stress as the key driver of oligomerization reactions under tribological conditions. Normal stress alone was ineffective in inducing any reactions and oligomerization could be driven thermally only at very high temperatures. Analysis of the reaction pathways showed that shear can activate multiple mechanisms that are not accessible thermally. Calculations of bond lengths and dihedral angles revealed that such activation is accompanied by physical deformation of reacting species. The findings from reactive molecular dynamics simulations provide critical insights into the activation mechanisms underlying mechanochemical reactions that can guide design of materials and processes with optimized and potentially tunable shear-induced reactions.