Linking Molecular Behavior to Macroscopic Properties in Ideal Dynamic Covalent Networks,Journal of the American Chemical Society

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Linking Molecular Behavior to Macroscopic Properties in Ideal Dynamic Covalent Networks
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2020-08-18 , DOI: 10.1021/jacs.0c06192
Bruno Marco-Dufort ₁ , Ramon Iten ₁ , Mark W Tibbitt ₁

Affiliation

Dynamic covalent networks (DCvNs) are increasingly used in advanced materials design with applications ranging from recyclable thermosets to self-healing hydrogels. However, the relationship between the underlying chemistry at the junctions of DCvNs and their macroscopic properties is still not fully understood. In this work we constructed a robust framework to predict how complex network behavior in DCvNs emerges from the chemical landscape of the dynamic chemistry at the junction. Ideal dynamic covalent boronic ester-based hydrogels were used as model DCvNs. We developed physical models that describe how viscoelastic properties, as measured by shear rheometry, are linked to the molecular behavior of the dynamic junction, quantified via fluorescence and NMR spectroscopy and DFT calculations. Additionally, shear rheometry was combined with Transition State Theory to quantify the kinetics and thermodynamics of network rearrangements, enabling a mechanistic understanding including preferred reaction pathways for dynamic covalent chemistries. We applied this approach to corroborate the 'loose-bolt' postulate for the reaction mechanism in Wulff-type boronic acids. These findings, grounded in molecular principles, advance our understanding and rational design of dynamic polymer networks, improving our ability to predict, design, and leverage their unique properties for future applications.

中文翻译：

将分子行为与理想动态共价网络中的宏观特性联系起来

动态共价网络 (DCvN) 越来越多地用于高级材料设计，其应用范围从可回收热固性材料到自修复水凝胶。然而，DCvNs 连接处的潜在化学与其宏观特性之间的关系仍未完全了解。在这项工作中，我们构建了一个强大的框架来预测 DCvN 中复杂的网络行为如何从连接处动态化学的化学景观中出现。理想的动态共价硼酸酯基水凝胶用作模型 DCvN。我们开发的物理模型描述了通过剪切流变测量法测量的粘弹性如何与动态结的分子行为相关联，通过荧光和核磁共振光谱以及 DFT 计算进行量化。此外，剪切流变测量与过渡态理论相结合，以量化网络重排的动力学和热力学，从而实现包括动态共价化学的首选反应途径在内的机理理解。我们应用这种方法来证实 Wulff 型硼酸反应机制的“松动螺栓”假设。这些以分子原理为基础的发现促进了我们对动态聚合物网络的理解和合理设计，提高了我们预测、设计和利用其独特性能用于未来应用的能力。Wulff 型硼酸的反应机理假设。这些以分子原理为基础的发现促进了我们对动态聚合物网络的理解和合理设计，提高了我们预测、设计和利用其独特性能用于未来应用的能力。Wulff 型硼酸的反应机理假设。这些以分子原理为基础的发现促进了我们对动态聚合物网络的理解和合理设计，提高了我们预测、设计和利用其独特性能用于未来应用的能力。

更新日期：2020-08-18

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