We demonstrate an experimental comparison of the bond lifetime, estimated using surface plasmon resonance (SPR), and the viscoelastic relaxation time of transient networks with well-controlled structures (dynamically cross-linked Tetra-PEG gel). SPR and viscoelastic measurements revealed that the temperature dependences of the two characteristic times are in agreement, while the viscoelastic response is delayed with respect to the lifetime by a factor of 2–3, dependent on the network strand length. Polymers cross-linked by temporary interactions form transient networks, which show fascinating viscoelasticity with a single relaxation mode. However, the molecular understanding of such simple viscoelasticity has remained incomplete because of the difficulty of experimentally evaluating bond lifetimes and heterogeneous structures in conventional transient networks. Our results suggest that bond dissociation and recombination both contribute to the macromechanical response. This report on direct bond-lifetime–viscoelastic-relaxation time comparison provides important information for the molecular design of transient network materials.

中文翻译：

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具有良好控制结构的瞬态网络中键寿命和粘弹性松弛的实验比较

我们展示了键寿命的实验比较，使用表面等离子体共振 (SPR) 估计，以及具有良好控制结构的瞬态网络的粘弹性弛豫时间（动态交联的 Tetra-PEG 凝胶）。SPR 和粘弹性测量表明，两个特征时间的温度依赖性是一致的，而粘弹性响应相对于寿命延迟了 2-3 倍，这取决于网络链长度。通过临时相互作用交联的聚合物形成瞬态网络，该网络显示出具有单一松弛模式的迷人粘弹性。然而，由于难以通过实验评估常规瞬态网络中的键寿命和异质结构，因此对这种简单粘弹性的分子理解仍然不完整。我们的结果表明，键解离和重组都有助于宏观机械响应。这份关于直接键寿命-粘弹性松弛时间比较的报告为瞬态网络材料的分子设计提供了重要信息。