AI 中文总结
本文开发了考虑三维构象涨落的统计力学框架，揭示张力下聚合物链断裂的构象介导动力学，为聚合物损伤与断裂的网络尺度模型提供物理输入。
AI 中文摘要
链断裂是聚合物网络损伤与断裂的关键分子过程。本文中，我们开发了一种统计力学框架，用于预测链断裂动力学，同时考虑三维（3D）构象涨落。基于过渡态理论，断裂被表述为多通道首次断裂问题，键特异性速率主要由自洽平均力势决定。在自由连接极限下，额外的三维构象自由度相较于共线一维参考体系增强了断裂概率；有限弯曲刚度会引入取向关联，这种关联可逆转该增强效应，且在高刚度下能将断裂速率降低数个数量级。这些关联还使断裂速率与键位置相关，链端附近速率更高，而链内部速率一致；对于足够长的链，内部贡献占主导，使链断裂速率与链长呈线性标度关系。这些分子层面解析的速率为未来聚合物损伤与断裂的网络尺度模型提供了物理上合理的输入。
英文摘要
Chain scission is a key molecular process underlying damage and fracture in polymer networks. In this Letter, we develop a statistical-mechanical framework for predicting chain-scission kinetics while accounting for three-dimensional (3D) conformational fluctuations. Within transition-state theory, scission is formulated as a multichannel first-rupture problem, with bond-specific rates governed primarily by self-consistent potentials of mean force. In the freely jointed limit, the additional 3D configurational freedom enhances rupture relative to the collinear 1D reference. Finite bending stiffness introduces orientational correlations that can reverse this enhancement and, at high stiffness, reduce rupture rates by orders of magnitude. These correlations also make rupture bond-position dependent, with higher rates near the chain ends and a common interior rate. For sufficiently long chains, the interior contribution dominates, yielding linear scaling of the chain-scission rate with chain length. These molecularly resolved rates provide physically grounded inputs for future network-scale models of polymer damage and fracture.
Comments46 pages, 12 figures
